Most studies examining the time to return to sport (RTS) after anterior cruciate ligament reconstruction (ACLR) do not account for the athlete's physical readiness. This study aimed to investigate the status of male athletes at 2 years after ACLR, the factors affecting a return to pivoting sports, and the association between time to RTS and subsequent knee injury risk for those athletes who met discharge criteria.

We prospectively followed 530 male athletes (mean age 26.7±7.7 years) participating in pivoting sports throughout rehabilitation and at 2 years after ACLR. Pair-wise analyses were conducted to compare athletes who returned to pivoting sports and those who did not. We performed a Cox regression analysis to assess the association between subsequent non-contact or indirect contact knee injuries and time to RTS. Pearson's χ2 test was used to compare athletes who RTS in ≤9 months to those who RTS in >9 months after ACLR.

In total, 379 (72%) athletes returned to pivoting sports at 2 years after ACLR. Athletes who completed rehabilitation and met discharge criteria (n=190) were almost 6 times more likely to return to their preinjury sport (OR 5.71; 95% CI 3.39 to 9.62). Of those who did not complete their rehabilitation (n=340), 132 (39%) did not return to pivoting sports. For athletes who met discharge criteria, time to RTS was not associated with the risk of new knee or ACL injury. There was no increased risk for new knee (HR 0.892, 95% CI 0.39 to 2.07, p=0.79) or ACL (HR 0.718, 95% CI 0.24 to 2.17, p=0.56) injury whether athletes returned before or after the 9-month mark following ACLR.

Completing rehabilitation and meeting objective criteria significantly increased the odds for male athletes to return to pivoting sports. Time to RTS did not impact the risk for a new knee or ACL injury if athletes met objective criteria.

An anterior cruciate ligament (ACL) injury is a severe condition that may affect the career of young athletes. There is limited evidence on the rate and level of return to sport (RTS) after pediatric and adolescent ACL reconstruction.

To evaluate clinical outcomes, the level and rate of RTS, and predictive factors for RTS after pediatric and adolescent ACL reconstruction.

Cohort study; Level of evidence, 3.

Patients aged between 10 and 18 years at the time of primary ACL reconstruction were screened for eligibility. Based on age at the time of ACL reconstruction, patients were divided into the pediatric (female: 11-13 years; male: 11-15 years) and adolescent (female: 14-18 years; male: 16-18 years) groups. Patient-specific, injury-related, and treatment-specific data, as well as subscores of the Knee injury and Osteoarthritis Outcome Score (KOOS) at baseline and 1-, 2-, 5-, and 10-year follow-up, were obtained. A survey consisting of 3 patient-specific and 30 knee-related questions was developed by experts in the management of ACL injuries and was sent to all patients to determine sport-specific variables and RTS rates.

Overall, 1392 patients (total response rate: 24%) were included in this study. There were 81 pediatric patients (mean age at ACL reconstruction, 13.7 ± 1.4 years) and 1311 adolescent patients (mean age at ACL reconstruction, 16.5 ± 1.2 years). Significant improvements in KOOS subscores were observed after both pediatric and adolescent ACL reconstruction at each follow-up time point. After ACL reconstruction, 74% of pediatric patients and 68% of adolescent patients returned to their previous type of sport (P = .23). Moreover, 31% of pediatric patients and 23% of adolescent patients became elite athletes (highest national level of junior sport or higher) after ACL reconstruction (P = .13). A cartilage injury at the time of ACL reconstruction was found to lower the odds of pediatric and adolescent patients returning to their previous type of sport (odds ratio, 0.60; P = .001). A second ACL injury occurred in 25% and 31% of pediatric and adolescent patients, respectively (P = .29).

Long-lasting clinical improvements and high RTS rates can be expected after pediatric and adolescent ACL reconstruction. Moreover, young athletes still have the chance to compete at an elite level of sport after ACL reconstruction.

This study aimed to determine the trends and indications for anterolateral complex augmentation during anterior cruciate ligament reconstruction (ACL-R) among international orthopedic sports surgeons.

An electronically distributed survey was sent out to international surgeons with high-volume experience in complex ligament reconstructions and revision surgery attending the 2024 Freddie Fu Panther Sports Medicine Symposium. The survey was sent prior to the meeting with questions related to the use of lateral extra-articular tenodesis (LET) or anterolateral ligament reconstruction (ALL-R) during ACL-R. Sessions pertaining to anterolateral complex augmentation were held during the symposium to inform about current clinical practices among attendees.

A total of 49 surgeons were identified from 5 different geographic regions prior to the meeting date and were sent an electronic survey, of which 48 responded (98% response rate). Among the surgeons who reported performing anterolateral complex augmentation procedures (n = 45), a total of 39 (87%) respondents reported using only the LET technique, 2 (4%) reported using only the ALL-R technique, and 4 (9%) reported using both techniques during ACL-R. The most common indication for anterolateral complex augmentation was a high-grade pivot shift, which 39 of 43 (91%) respondents ranked in their top 3 indications. In the setting of primary ACL-R, respondents added LET when using hamstring tendon autograft in 38% of cases on average compared with 34% of cases when using either bone-patellar tendon-bone autograft or quadriceps tendon autograft. In the setting of revision ACL-R, LET was added in an average of 68% of cases for a first-time revision ACL-R and in 84% of cases for a multiple-revision ACL-R.

The most common indication for ACL-R with anterolateral complex augmentation was a high-grade pivot shift and most respondents preferred LET over ALL-R. Respondents performed LET in a comparable percentage of cases of primary ACL-R using hamstring tendon, bone-patellar tendon-bone, and quadriceps tendon autografts, and this number increased with the number of revision ACL-Rs. Based on the results of this survey, surgeons may consider adding LET in cases of revision ACL-R or in patients with a high-grade pivot shift.

Level V.

While both iliotibial band graft augmented by gracilis tendon (ITB + G) and hamstring autograft with modified Lemaire lateral extra-articular tenodesis (STG + LET) are established techniques for addressing rotatory instability in anterior cruciate ligament reconstruction, no direct comparison exists between these approaches. The purpose of this study was to provide the first direct comparison between these two surgical techniques regarding graft survival, functional outcomes and return to sport.

This single-centre, single-surgeon retrospective study analyzed 56 patients (28 per group) after 1:1 propensity score matching based on age, gender and Tegner activity scale. Primary end point was failure (graft retear or secondary meniscal lesion). Secondary outcomes included the International Knee Documentation Committee (IKDC), anterior cruciate ligament-return to sport after surgery (ACL-RSI) scores, and return to sport rate. Kaplan-Meier survival analysis and between-group comparisons were performed using appropriate statistical tests.

At mean follow-up of 53.3 ± 6.4 months, failure-free survival rates at 24 months were 85.7% (95% confidence interval [CI]: 66.3-94.4) for STG + LET and 89.3% (95% CI: 70.4-96.4) for ITB + G (p = 0.664). Graft retear rate was 7.1% (STG + LET: 3.6%, ITB + G: 10.7%). Secondary meniscal injuries occurred equally (14.3%) in both groups. Return-to-sport rate was 89.3% at mean of 9.6 ± 3.9 months. Mean IKDC scores were 87.5 ± 11.4 for STG + LET and 83.6 ± 16.3 for ITB + G, with 73.7% achieving Patient Acceptable Symptom State criteria. ACL-RSI scores were similar between groups (STG + LET: 74.2 ± 24.3 and ITB + G: 73.5 ± 26.8).

No significant differences were found between ITB + G and STG + LET techniques regarding failure rates, return to sport and functional outcomes. Both techniques achieved satisfactory results in this cohort, with similar complication profiles. This comparison provides valuable clinical guidance, supporting surgical decision-making based on surgeon experience.

Level III, retrospective cohort study.

Favorable outcomes after anterior cruciate ligament (ACL) reconstruction (ACLR) are often gauged by successful return to play (RTP), a low incidence of subsequent ACL injury, and positive patient-reported outcomes. Level 1 sports place the highest demands on the knee by requiring frequent pivoting, changes in direction, and jumping.

To analyze the outcomes of primary ACLR in level 1 athletes and identify pre- and intraoperative factors associated with RTP, ipsilateral ACL reinjury, contralateral ACL injury, and International Knee Documentation Committee (IKDC) score at 5 years postoperatively.

Cohort study; Level of evidence, 2.

A consecutive cohort of 1432 patients who underwent primary ACLR by 2 orthopaedic surgeons were prospectively evaluated. The RTP rate, incidence of ipsilateral/contralateral ACL injury, and IKDC score were analyzed at 5 years. Comparative analysis of clinical variables was performed between those who achieved favorable outcomes and those who did not. Outcomes at 5 and 2 years were also compared.

The mean age was 24.3 ± 7.3 years (males: 75%, females: 25%). Gaelic football was the predominant sport (40%), followed by soccer (19%). The RTP rate was 87.4%, with 59.8% of athletes still playing at an equivalent or higher level at 5 years. The incidence of ipsilateral reinjury for athletes who resumed level 1 sport was 4.3% for bone-patellar tendon-bone (BPTB) autografts with screw fixation and 19.7% for hamstring tendon (HT) autografts with EndoButton and screw fixation. The incidence of contralateral ACL injury was 13.7%. The mean IKDC score at 5 years (86.6 ± 10.9) was comparable to that at 2 years (86.8 ± 10.1). Patients were more likely to RTP with each year of decreasing age (OR, 1.06; P < .001), with a higher preoperative Marx score (OR, 1.08; P < .001) or a higher 5-year IKDC score (OR, 1.06; P < .001). The risk of ipsilateral ACL reinjury increased each year of decreasing age (OR, 1.11; P < .001) or when an HT autograft was used (OR, 5.56; P < .001). Younger age was also associated with contralateral ACL injury (OR, 1.1; P < .001). Female sex, older age, concomitant meniscal/chondral injuries, and lower preoperative Anterior Cruciate Ligament Return to Sport after Injury scores were associated with lower IKDC scores at 5 years.

Most patients could return to level 1 sports, although their performance level was impacted. Those who returned to sport maintained their performance level over the 5 years. The ipsilateral reinjury rate for BPTB autografts with screws was significantly lower than that for HT autografts with EndoButton and screw fixation. Most ACL reinjuries occurred between 2 and 5 years of follow-up. Younger patients had an increased risk of a subsequent ACL injury to either knee, regardless of graft type. IKDC scores were lower in female patients, older patients, and those with concomitant meniscal/cartilage injuries.

NCT02771548 (ClinicalTrials.gov identifier).

Failed anterior cruciate ligament reconstruction (ACLR) leads to reduced quality of life and sometimes the need for repeat surgery. The reason for failure can be multifactorial and difficult to determine. Reports on failure leading to revision are few with limited generalizability. Also, no studies have investigated the reasons for early (<2 years) versus late (≥2 years) revision.

To describe patients undergoing revision surgery, the surgeon's reported cause of failure, and the risk of undergoing early versus late revision surgery.

Cohort study; Level of evidence, 3.

Primary ACLR cases without concomitant ligament injuries or surgery, registered in the Norwegian Knee Ligament Register from 2004 throughout 2023, were eligible. Descriptive analyses were conducted on intraoperative findings and procedures, time from injury to surgery, activity at the time of injury, revision surgery, surgeon-reported cause of revision, and reporting method. The Kaplan-Meier method was used to calculate revision rates. A multivariable Cox regression model, adjusted for confounders, was used to calculate the hazard ratio of early and late revision surgery.

A total of 30,035 primary ACLR cases were analyzed, of which 1599 resulted in revision surgery. The overall revision rate was 7.1% at 15 years. Female patients were younger at the time of both primary and revision surgery (23.8 and 22.5 years, respectively) compared with male patients (28.2 and 22.2 years, respectively). Age at the time of primary surgery was significantly lower for patients who underwent revision (20.4 years) compared with those who did not undergo revision (26.5 years). Male sex, lower age, hamstring tendon graft, and no cartilage injury at the time of primary reconstruction were all associated with a higher risk of early revision. Lower age, hamstring tendon graft, and no meniscal injury were associated with a higher risk of late revision. New trauma (38.1%) was found to be the most common cause of failure leading to revision.

In the current study, representing one of the largest cohorts to date investigating failed primary ACLR leading to revision, the overall 15-year revision rate was estimated as 7.1%. Patients receiving hamstring tendon grafts were at a particular risk for early revision during the first 2 years after primary reconstruction. New trauma was the most common reported cause of failure leading to revision ACLR.

Anterior cruciate ligament (ACL) injuries are common in pediatric and adolescent patients. Understanding this population's injury characteristics and treatment strategies is vital for managing this high-risk group.

To report the descriptive epidemiology and treatment strategies of a large cohort of skeletally immature patients with complete ACL tears.

Cross-sectional study; Level of evidence, 2.

Consecutive skeletally immature patients diagnosed with complete ACL tears were enrolled at 10 institutions across the United States. Treatment was provided by 1 of 23 participating orthopaedic surgeons. Patient characteristics (chronological and skeletal age, sex, race, and ethnicity) as well as anthropometric measures, mechanism of injury, and ACL treatment type were collected.

A total of 749 skeletally immature participants were included in the final cohort; the mean chronological age was 12.9 years, and 62% were male. The mean skeletal age (13.2 years) was a mean of 0.34 years (4 months) higher than the mean chronological age (P < .001). Tanner staging revealed that 18% of participants were Tanner stage 1, 20% were Tanner stage 2, 28% were Tanner stage 3, 30% were Tanner stage 4, and 4% were Tanner stage 5. Five percent of participants reported a previous ipsilateral knee injury, and 30% had a family history of ACL injuries. Sport was the predominant mechanism of injury (89%), with noncontact injuries the most common (64%). The most common sport resulting in an ACL tear among boys was American football (41%) and among girls was soccer (44%). Overall, 99.9% of skeletally immature patients were treated surgically by 1 of 4 reconstruction techniques: transphyseal (53%), partial transphyseal (7%), physeal-sparing all-epiphyseal (13%), and physeal-sparing iliotibial band (ITB) (27%). The most common surgical techniques for patients with a skeletal age <13 years were physeal sparing with ITB (56%) and all-epiphyseal (22%), while in patients with a skeletal age ≥13 years, transphyseal (71%) and physeal sparing with ITB (12%) were the most common. Overall, 57% of patients who underwent ACL reconstruction had arthroscopically documented meniscal tears, with high rates of meniscal repair (90% medial tears and 66% lateral tears).

Almost all skeletally immature patients with ACL tears were injured during sports, surgical treatment was overwhelmingly the treatment of choice, and preferred surgical techniques varied based on skeletal ages.

Epidemiological studies have shown an increased risk of musculoskeletal injury after concussion. The purpose of this study was to determine whether the reverse relationship exists, specifically whether there is an increased risk of concussion after an anterior cruciate ligament (ACL) injury in a population-based cohort.

Retrospective cohort.

The Rochester Epidemiology Project was searched between 2000 and 2017 for International Classification of Diseases, 9th and 10th Revision codes relevant to the diagnosis and treatment of concussion and ACL tear. A total of 1294 unique patients with acute, isolated ACL tears and no previous history of concussion were identified. Medical records for cases were reviewed to confirm ACL tear diagnosis and to determine history of concussion after the ACL injury. Cases were matched by age, sex, and Rochester Epidemiology Project availability to patients without an ACL tear (1:3 match), resulting in 3882 controls. Medical records of matched control patients were reviewed to rule out history of ACL injury. The hazard ratio of concussion injury following an ACL injury was determined.

Nine patients with an ACL injury suffered concussion up to 3 years after the ACL injury. The rate of concussion was no different between ACL-injured cases (0.7%) compared with matched controls with no ACL injury (1.2%), which corresponded to a hazard ratio of 0.55 (95% confidence interval, 0.3-1.1; P = .10).

Based on the current evidence, there does not appear to be a significant association between ACL injury and subsequent concussion, which suggests that a concussion uniquely affects the risk of future subsequent musculoskeletal injury.

Anterior cruciate ligament (ACL) reconstruction (ACLR) aims to restore knee stability and function; however, recovery outcomes vary widely, highlighting the need for predictive tools to guide rehabilitation and patient readiness.

To identify the most effective machine learning models for predicting the successful recovery of Patient Acceptable Symptom State (PASS) in terms of subjective function, symptoms, and psychological readiness 12 months after ACLR using physical performance measures obtained 3 months after ACLR.

Cohort study; Level of evidence, 3.

The authors retrospectively analyzed the data of 113 patients who underwent single-bundle anatomic ACLR. Physical performance measures at 3 months after ACLR included the Y-balance and isokinetic muscle strength tests. The successful recovery of PASS outcomes at 12 months were assessed using the International Knee Documentation Committee (IKDC) and the ACL-Return to Sport after Injury (ACL-RSI) scale. Five machine learning algorithms were assessed: logistic regression, decision tree, random forest, gradient boosting, and support vector machines.

The gradient boosting model demonstrated the highest area under the curve (AUC) scores for predicting SRPAS of the IKDC (AUC, 0.844; F1, 0.889), and the random forest model demonstrated the highest AUC scores for predicting the successful recovery of PASS of the ACL-RSI (AUC, 0.835; F1, 0.732) during test models. Key predictors of the successful recovery of PASS outcomes included young age and low deficits in the 60 deg/s flexor and extensor peak torque for the IKDC, low 180 deg/s extensor and flexor mean power deficit, and low 60 deg/s flexor peak torque deficits for the ACL-RSI.

Machine learning showed that younger age and greater 3-month isokinetic strength at 60 deg/s predicted attainment of the successful recovery of PASS of the IKDC at 1 year after ACL. Greater 3-month isokinetic strength at 180 deg/s was most predictive of attaining the successful recovery of PASS of the ACL-RSI at 12 months.

It remains unknown whether anterior cruciate ligament (ACL) reconstruction (ACLR) alters the natural history of degenerative changes or prevents further injury compared with nonoperative treatment.

The purpose of this study was to evaluate the midterm risk of knee surgery in patients who sustained an ACL tear treated with initial nonoperative management. It was hypothesized that the majority of patients who pursue initial nonoperative treatment after ACL rupture will not undergo further surgery within 5 years.

Case series; Level of evidence, 4.

An electronic health record search was performed for all patients aged 12 to 65 years from 2011 to 2012 with magnetic resonance imaging-confirmed ACL tear. Patients who did not undergo ACLR within 6 months after diagnosis comprised our initial cohort. Patients were longitudinally followed until August 31, 2017. The primary outcome was an occurrence of ipsilateral knee surgery, including ACLR and non-ACLR procedures.

A total of 932 patients with a mean age of 36.2 ± 13.6 years were included. The mean follow-up time was 57.9 ± 7.4 months. During the follow-up period, 365 patients (39.2%) had ipsilateral knee surgery, with a mean time from ACL tear diagnosis to the first procedure of 11.9 ± 13.0 months. Overall, 67% of surgeries occurred within 12 months of diagnosis. ACLR was performed in 211 patients (22.6%); 284 patients had non-ACLR knee procedures, with 130 undergoing ACLR and non-ACLR surgery and 154 patients undergoing non-ACLR procedures alone. After adjusting for demographic and clinical factors, younger age remained a significant risk factor for undergoing ACLR: patients aged 12 to 18 years and those aged 19 to 30 years had similar adjusted hazard ratios compared with patients aged 51 to 65 years (5.49 [95% CI, 2.78-10.88] and 5.48 [95% CI, 2.85-10.53], respectively; P < .001 for both).

In this universally insured, contained patient cohort, 39.2% of the patients underwent a subsequent surgical procedure on the ipsilateral knee within 5 years of ACL injury, with 22.6% of patients opting to undergo delayed ACLR. Younger age was an independent risk factor for undergoing ACLR.

Although high rates of graft and contralateral anterior cruciate ligament (ACL) ruptures have been reported in younger patients after ACL reconstruction (ACLR), recent evidence suggests that previously reported crude event rates underestimate the actual event risk.

To report rates of graft and contralateral ACL rupture after ACLR in a large series of younger patients using survival analysis.

Cohort study; Level of evidence, 3.

Patients aged <18 years at the time of primary ACLR were identified from a single-surgeon database over 12 years ending January 2018. Patients with a previous contralateral ACL rupture or bilateral ACL ruptures were excluded. Overall, 388 patients (204 males, 184 females) were included in the final dataset. Bespoke survey data and clinic follow-up data were used to record graft rupture and contralateral ACL rupture events. Rates of graft and contralateral ACL rupture were calculated using Kaplan-Meier survival analysis. Log-rank tests were used to compare survival functions between several subgroups.

According to Kaplan-Meier survival analysis, the cumulative rates at 2, 5, and 10 years for graft rupture were 11%, 17%, and 22%, and the cumulative rates for contralateral ACL injury were 7%, 19%, and 33%. Males had significantly greater rates of graft rupture than females throughout a 10-year follow-up period (P < .001). Contralateral ACL rupture survival functions were not significantly different between the sexes, although rates were higher in females until 5 years postoperatively, after which contralateral ACL ruptures increased in males, with a cumulative rate of 39% at 10 years compared with 29% for females. Survival rates did not vary between different age groups (<16 vs ≥16 years), but females with a graft diameter of <7 mm on the femoral side had significantly greater graft rupture rates than females with grafts ≥7 mm (P = .04).

The present study is one of the largest consecutive series of younger patients, with one of the longest follow-up periods, reporting a high risk for a second ACL injury. Over time, the cumulative risk for contralateral ACL rupture was higher than for graft rupture. In males, the risk for contralateral ACL rupture continued to increase after 5 years.

To investigate the rate and timing for return to football league games after anterior cruciate ligament reconstruction (ACLR) in Swedish players, examining associations with sex, age, level, graft and additional ACL surgery.

Data from the Swedish National Knee Registry (SNKLR) and the Swedish Football Association's IT System (FOGIS) were used. The study cohort comprised 971 football players, 64% males, who underwent primary ACLR. Demographics, graft type and surgical information were extracted from the SNKLR and game participation from FOGIS. Follow-up for return to competition (RTC) was conducted for 36 months, while additional ACLR follow-up was 3-7 years. Statistical analyses, including Kaplan-Meier survival curves and relative risk calculations, were employed to assess factors influencing RTC rates and timing.

Out of 971 players analyzed, 53% RTC within 3 years with no difference between males and females, at a mean of 15 months (median 14 months) from surgery to the first game. Eleven (2%) players RTC < 6 months from ACLR, 62 (12%) 6-9 months, 125 (24%) 9-12 months and 331 (63%) >12 months. Patellar tendon (PT) grafts demonstrated superior performance, showing quicker returns and higher RTC rates (p = 0.005) compared to hamstring (hazard ratio [HR]: 0.63 [0.48-0.84]) and quadriceps tendon grafts (HR: 0.53 [0.30-0.93]). Players competing in higher divisions pre-injury experienced significantly swifter and higher RTC rates (p < 0.001). Ninety-five (10%) had a registered additional ACLR. Players who RTC did not exhibit a significantly higher rate of revision (35 [7%] vs. 25 [5%]). However, those who returned faced a heightened risk of contralateral ACLRs compared to those who did not RTC (32 [6%] vs. 4 [1%] RR 1.72 [1.59-1.96], p < 0.001).

The study reveals that 53% of football players RTC after ACLR, predominantly after more than 12 months. The RTC was higher and faster in high-level players and those receiving a PT graft. The slow RTC may contribute to the relatively low rate of additional ACLRs.

Level III.

To evaluate the impact of age as a risk factor on the revision rates of anterior cruciate ligament (ACL) primary repair (ACLPR), dynamic intraligamentary stabilization (DIS) and bridge-enhanced ACL restoration (BEAR) compared to ACL reconstruction (ACLR).

A systematic literature search was performed for comparative studies comparing outcomes for ACLPR, DIS or BEAR to ACLR. A random-effects meta-analysis was performed to assess nondifferentiated and age-differentiated (skeletally mature patients ≤21 and >21 years) ACL revision and reoperation risk, as well as results for subjective outcomes. Methodological study quality was assessed using the Risk of Bias Tool 2.0c and Methodological Index for Nonrandomized Studies tools.

A total of 12 studies (n = 1277) were included. ACLR demonstrated a lower nonage-stratified revision risk at 2 years versus ACLPR, DIS and BEAR, but a similar revision risk at 5 years when compared to DIS. However, an age-stratified analysis demonstrated a significantly increased ACLPR revision risk as compared to ACLR in skeletally mature patients ≤21 years of age (risk ratios [RR], 6.33; 95% confidence interval [CI], 1.18-33.87, p = 0.03), while adults (>21 years) showed no significant difference between groups (RR, 1.48; 95% CI, 0.25-8.91, n.s.). Furthermore, DIS reoperation rates were significantly higher than respective ACLR rates (RR, 2.22; 95% CI, 1.35-3.65, p = 0.002), whereas BEAR (RR, 1.07; 95% CI, 0.41-2.75, n.s.) and ACLPR (RR, 0.81; 95% CI, 0.21-3.09, n.s.) showed no differences. IKDC scores were equivalent for all techniques. However, ACLPR exhibited significantly better FJS (mean difference, 11.93; 95% CI, 6.36-17.51, p < 0.0001) and Knee injury and Osteoarthritis Outcome Score Symptoms (mean difference, 3.01; 95% CI, 0.42-5.60, p = 0.02), along with a lower Tegner activity reduction.

ACLPR in skeletally mature patients ≤21 years of age is associated with up to a six-fold risk increase for ACL revision surgery compared to ACLR; however, adults (>21 years) present no significant difference. Based on the current data, age emerges as a crucial risk factor and should be considered when deciding on the appropriate treatment option in proximal ACL tears.

Level III.

Primary anterior cruciate ligament (ACL) reconstruction graft failure remains a significant health concern in young patients. Despite the high incidence of poor graft integration in these patients and the resulting high failure rate, little consideration has been given to the quality of the bone into which the graft is anchored at reconstruction. Therefore, we investigated post ACL injury mineralized tissue changes in the ACL femoral entheses of young males and compared them to changes previously reported for young females.

ACL femoral entheses and adjacent bone specimens were harvested from the injured knees of 51 young males during primary ACL reconstructive surgery and from 10 non-injured male cadaveric donors. The specimens were imaged via nano-computed tomography and analyzed for volumetric bone mineral density (vBMD) and architectural changes.

Male femoral ACL explant specimens had significantly lower cortical vBMD (p < 0.001), lower relative bone volume (BV/TV, p = 0.027) and greater cortical bone porosity (Ct.Po, p = 0.027) but similar trabecular bone parameters (p's > 0.05) to those of control specimens from male cadaveric donors. Cortical and trabecular bone loss increased significantly with time from ACL injury to reconstructive surgery (p's < 0.05). While cortical loss occurred in both males and females, significant trabecular loss occurred only in females (p = 0.009).

Femoral entheseal bone loss occurs in males following ACL injury. This bone loss increases with time following ACL injury, with cortical bone loss occurring sooner after injury than trabecular bone loss. The effects of ACL injury and time from injury to surgery on trabecular bone microarchitecture differed between male and female patients.

N/A.

Objectives: There remains considerable debate regarding the optimal management of anterior cruciate ligament (ACL) injuries in skeletally immature patients. This study aims to evaluate the clinical outcomes of transphyseal ACL reconstruction in patients with open growth plates. Methods: This retrospective study included skeletally immature patients with full-thickness ACL tears and confirmed open physis. ACL reconstructions were performed using a four-strand semitendinosus autograft, with an additional gracilis tendon graft if needed. The surgical technique emphasized tibial and femoral physeal-sparing tunnel placement to minimize disruption of the growth plates. Clinical assessment included measurements for limb length discrepancy, knee stability, and growth disturbances. Functional outcomes were evaluated using IKDC 2000, Lysholm, and KOOS scores, while ligament stability was assessed with KT-1000 arthrometer measurements at routine follow-up. Results: A total of 31 consecutive patients (15 females, 16 males; mean age 13.6 ± 1.8 years, range 9-16 years) were included. Mean follow-up was 49 ± 26 months (range 18-93 months). The mean time to return to sports was 8.8 ± 4.4 months. Eight patients (26%) experienced ACL graft rupture and underwent revision ACL reconstruction. One additional patient required partial meniscectomy. The overall revision rate was 29%. The mean subjective IKDC score was 91.8 ± 7.2, with Lysholm and KOOS scores of 96.6 ± 7.9 and 94.2 ± 5.3, respectively. No significant growth disturbances were noted. The mean side-to-side difference in KT-1000 testing was 2.2 ± 1.5 mm. Patients who underwent revision ACL reconstruction showed significantly greater length growth compared with those with intact ACL reconstruction (p = 0.02). Spearman correlation revealed a significant association between length growth and anterior tibial translation (p = 0.02, r = 0.46). Conclusions: Transphyseal ACL reconstruction in skeletally immature patients provides favorable clinical and radiological outcomes, with minimal risk of growth disturbance. Most patients returned to pre-injury levels of athletic activity. However, the high revision rate emphasizes the complexity of managing ACL injuries in this population.

Increased tibial slope has been shown to lead to higher rates of anterior cruciate ligament graft failure. A slope-decreasing osteotomy can reduce in situ anterior cruciate ligament force and may mitigate this risk. However, how this procedure may affect the length change behavior of the medial ligamentous structures is unknown.

The purpose of this study was to examine the effect of anterior slope-modifying osteotomies on the medial ligamentous structures. It was hypothesized that (1) decreasing the tibial slope would lead to shortening of the superficial medial collateral ligament (sMCL), (2) while the fibers of the posterior oblique ligament (POL) would be unaffected.

Descriptive laboratory study.

Eight fresh-frozen cadaveric knee specimens underwent anatomic dissection to precisely identify the medial ligamentous structures. The knees were mounted in a custom-made kinematics rig with the quadriceps muscle and iliotibial tract loaded. An anterior slope-modifying osteotomy was performed and fixed using an external fixator, which allowed modification of the wedge height between -15 and +10 mm in 5-mm increments. Threads were mounted between pins positioned at the anterior, middle, and posterior parts of the tibial and femoral attachments of the sMCL and POL. For different tibial slope modifications, length changes between the tibiofemoral pin combinations were recorded using a rotary encoder as the knee was flexed between 0° and 120°.

All sMCL fiber regions shortened with slope reduction (P < .001) and lengthened with slope increase (P < .001), with the anterior sMCL fibers more affected than the posterior sMCL fibers. A 15-mm anterior closing-wedge high tibial osteotomy (ACWHTO) resulted in a 6.9% ± 3.0% decrease in the length of the anterior sMCL fibers compared with a 3.6% ± 2.3% decrease for the posterior sMCL fibers. A 10-mm anterior opening-wedge high tibial osteotomy (AOWHTO) increased anterior sMCL fiber length by 5.9% ± 2.3% and posterior sMCL fiber length by 1.6% ± 1.0%. The POL fibers were not significantly affected by a slope-modifying osteotomy.

Tibial slope-modifying osteotomies changed the length change pattern of the sMCL such that an AOWHTO increased whereas an ACWHTO decreased the sMCL strain. This effect was most pronounced for the anterior fibers of the sMCL. The length change pattern of the POL remained unaffected by slope-modifying osteotomy.

Surgeons should be aware that anterior tibial slope-modifying osteotomies affect the biomechanics of the sMCL. After an extensive ACWHTO, patients may develop a medial or anteromedial instability, while an AOWHTO may overconstrain the medial compartment.

Anterior cruciate ligament (ACL) reconstruction (ACLR) can be successful in restoring knee stability. However, secondary ACL injury, either through graft failure or contralateral injury, is a known complication and can significantly impact the ability of a patient to return successfully to previous activities.

To develop and internally validate an interpretable machine learning model to quantify the risk of graft failure and contralateral ACL injury in a longitudinal cohort treated with ACLR.

Case-control study; Level of evidence, 3.

An established geographic database of >600,000 patients was used to identify patients with a diagnosis of ACL rupture between 1990 and 2016 with a minimum 2-year follow-up. Medical records were reviewed for relevant patient information and 4 candidate machine learning algorithms were evaluated for prediction of graft failure and contralateral ACL injury in patients after ACLR as identified either on magnetic resonance imaging or via arthroscopy. Performance of the algorithms was assessed through discrimination, calibration, and decision curve analysis. Model interpretability was enhanced utilizing global variable importance plots and partial dependence curves.

A total of 1497 patients met inclusion criteria. Among them, 140 (9.4%) had graft failure and 128 (8.6%) had a contralateral ACL injury after index surgery at a median follow-up of 140.7 months (interquartile range, 77.2-219.2 months). The best performing models achieved an area under the receiver operating characteristics curve of 0.70 for prediction of graft failure and 0.67 for prediction of contralateral ACL injury, outperforming a logistic regression fitted on the identical feature set. Notable predictors for increased risk of graft failure included younger age at injury, body mass index (BMI) <30, return to sports <13 months, initial time to surgery >75 days, utilization of allograft, femoral/tibial fixation with suspension/expansion devices, concomitant collateral ligament injury, and active or former smoking history. Predictors of contralateral ACL injury included greater preoperative pain, younger age at initial injury, BMI <30, active smoking history, initial time to surgery >75 days, history of contralateral knee arthroscopies, and involvement in contact sports.

Less than 18% of all patients who undergo ACLR should be expected to sustain either a graft failure or contralateral ACL injury. Machine learning models outperformed logistic regression and identified greater preoperative pain, younger age, BMI <30, earlier return to higher activity, and time to surgical intervention >75 days as common risk factors for both graft failure as well as contralateral ACL injury after ACLR. Surgeon-modifiable risk factors for graft failure included allograft and femoral/tibial fixation with a suspension/expansion combination.

Low return to competitive sport, high reinjury rates and long-term functional impairment of anterior cruciate ligament reconstruction (ACLR) present significant challenges for patients. A program that facilitates a safe return to sport (RTS) following ACLR could potentially improve outcomes.

Case Series.

Sixty participants (median 20-years-old (13-36), 43 males, 18 females, median 7.5 months (4-25) post-ACLR) completed an eight-week exercise program. A battery of physical tests and patient-reported outcome measures were assessed pre and post-program. The number of participants passing RTS criteria was evaluated, and RTS rates were determined. The correlation between the ACL-RSI and measures of physical function was explored.

Improvements in all isometric strength, hop tests, running T-test, and patient reported outcome measures were seen post-program. Five (8%) participants successfully passed all RTS criteria and eighty-five percent of participants returned to their previous level of sport. The ACL-RSI and the IKDC showed correlation across all time points (pre rs = 0.49; post rs = 0.40; change r = 0.40).

Our study demonstrated improvements in all RTS criteria tests upon completing the 8-week rehabilitation program; however, few participants (8%) passed all RTS criteria. Psychological readiness is more closely related to patient-reported function than functional tests.

To report the rate of anterior cruciate ligament (ACL) graft failure by physis status (open, closing, closed) and to analyze which factors were associated with higher risk of ACL graft failure.

Patients younger than 18 years who underwent transphyseal ACL reconstruction (ACLR) between 2000 and 2018 at a single institution were reviewed at minimum 2 years after ACLR. Patient records were reviewed for anthropometrics, surgical techniques, and ACL graft failure. Patients were subsequently stratified based on physis status (open, closing, closed) and analyzed.

A total of 272 patients (mean age of 15.4 ± 1.3 years) were assessed. The transtibial technique was used in 63.6% of cases. A hamstring autograft was used exclusively in the open physis group. A patellar tendon autograft was used in 65.9% of patients with a closing physis and 80.9% of patients with a closed physis. The overall graft failure rate was 13.2%, with a contralateral ACL injury rate of 11.0%. Kaplan-Maier analysis by physis status showed different injury free from ACL reinjury (P < .001). An open physis was associated with increased risk of ACL reinjury (hazard ratio, 5.2; P < .001) when compared to a closed physis. A closing physis presented a higher hazard ratio but was not statistically significant (hazard ratio, 2.6; P = .08). Hamstring graft type (P = .03) and lower graft diameter (P = .04) were significantly related to higher ACL reinjury after adjusting for physis status.

Transphyseal ACLR is a safe procedure in pediatric patients. The rate of reinjury was 13.2%. This rate decreases with skeletal maturity, use of patellar tendon autograft, and a larger graft diameter.

Level III, retrospective cohort study.

To investigate the patient-reported outcomes (PROs), knee stability, and complications in prospective comparative studies of patients undergoing augmented anterior cruciate ligament (ACL) repair compared with anterior cruciate ligament reconstruction (ACLR).

A literature search was performed according to the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Human clinical studies of Level I-II evidence comparing PROs, knee stability, and complications after ACL repair and reconstruction were included, and a qualitative analysis was performed. Excluded studies included those lacking reporting outcomes, studies that performed open ACLR or repair, studies published before the year 2000, and studies with evidence Levels III-IV. Study quality was assessed using the Cochrane Collaboration's risk of bias tool.

Seven Level I-II studies were retained, comprising 190 ACLR and 221 repairs (75 bridge-enhanced ACL repair [BEAR], 49 suture augmentation [SA], and 97 dynamic intraligamentary stabilization [DIS]). At final follow-up, re-rupture rates varied between 0 and 14% (BEAR) versus 0 and 6% (ACLR) and mean side-to-side differences measured using KT-1000 testing ranged from 1.6 to 1.9 mm (BEAR) versus 1.7 to 3.14 mm (ACLR). For DIS versus ACLR, mean anterior tibial translation values at final follow-up were 1.7 mm (DIS) versus 1.4 mm (ACLR), and re-rupture rates ranged from 20.8% to 29% (DIS) versus 17% to 27.2% (ACLR). For SA versus ACLR, the mean side-to-side difference ranged from 0.2 to 0.39 mm (SA) versus 0.33 to 0.4 mm (ALCR), whereas the re-rupture rates were 10% (SA) versus 0% (ACLR). International Knee Documentation Committee, Tegner, Lysholm, and Knee Injury and Osteoarthritis Outcome scores across both cohorts exhibited statistically significant, and comparable improvement, from baseline to final follow-up ranging from 1 to 5 years.

Augmented ACL repair results in similar patient-reported outcome measures in comparison with ACLR. However, augmented ACL repair may be associated with greater rates of failure, given re-rupture rates of up to 14%, 29%, and 10% for BEAR, DIS, and SA, respectively.

Level II, systematic review of Level I-II studies.

Adolescent athletes who sustain a musculoskeletal sports injury are at high re-injury risk. This prospective study evaluated athletic identity perception and fear avoidance perception relationships during the return to sport preparation phase of musculoskeletal injury rehabilitation.

From 140 consecutive physical therapy outpatients, 50 (26 females, 24 males) adolescent athletes (mean age 16.8, range 14 to 22 y) completed the 7-item Athletic Identity Measurement Scale (AIMS), the 10-item Athletic Fear Avoidance Questionnaire (AFAQ), and the AFAQ with 2 additional movement-related fear and pain questions (AFAQ+). Correlational analysis was performed of overall AIMS and AIMS subscale scores (social identity, exclusivity, negative affectivity), with AFAQ and AFAQ+ scores ( P ≤0.05).

Adolescent athletes were receiving treatment for musculoskeletal injuries sustained during soccer (n=10), lacrosse (n=7), baseball (n=6), basketball (n=5), volleyball (n=5), track or cross country (n=4), American football (n=4), field hockey or ice hockey (n=3), softball (n=2), tennis (n=2), and gymnastics (n=2). Lower extremity conditions included anterior cruciate ligament reconstruction (n=23) or other lower extremity conditions (n=17). Upper extremity conditions included shoulder dislocation or labral repair (n=6), elbow sprain or fracture (n=3), and clavicle fracture (n=1). The AIMS score displayed moderate inverse relationships with AFAQ ( r =-0.40, P =0.008) and AFAQ+ ( r =-0.41, P <0.004) scores. The "social identity" AIMS subscale score displayed a moderate inverse relationship with AFAQ ( r =- 0.48, P <0.001) and AFAQ+ ( r =-0.46, P =0.001) scores. The "exclusivity" AIMS subscale score displayed moderate inverse relationships with AFAQ ( r =-0.40, P =0.005) and AFAQ+ ( r =-0.46, P =0.001) scores. The "negative affectivity" subscale did not display significant relationships with AFAQ or AFAQ+ scores. Subject age displayed moderate inverse relationships with the AIMS "social identity" ( r =-0.56, P <0.001) and "exclusivity" ( r =-0.42, P =0.004) subscale scores and weak direct relationships with AFAQ (r=0.30, P =0.04) and AFAQ+ (r=0.32, P =0.02) scores.

Adolescent athletes with stronger athletic identity perceptions during the return to the sports preparation phase of musculoskeletal injury rehabilitation had weaker fear avoidance perceptions. As age increased from early to late adolescence, athletic identity perceptions became weaker, and fear avoidance perceptions became stronger. To decrease re-injury rates, early identification and surveillance of injured adolescent athletes with stronger, more exclusive athletic identity perceptions and weaker fear avoidance perceptions may influence rehabilitation progression and return to play decisions.

Level-II, prospective cohort, correlational study.

Readiness for return to sports involves both physical and psychological aspects of recovery; however, the relationship between psychological and physical variables after anterior cruciate ligament (ACL) reconstruction (ACLR) is poorly understood.

ACLR patients with a higher psychological readiness would demonstrate better functional testing results at 6 months.

Cross-sectional study; Level of evidence, 3.

Participants were evaluated at 6 months after ACLR with various patient-reported outcome metrics: Hospital for Special Surgery Pediatric Functional Activity Brief Scale, pediatric or adult International Knee Documentation Committee Questionnaire (IKDC), Patient-Reported Outcomes Measurement Information System (PROMIS) - Psychological Stress Experience and ACL - Return to Sport After Injury (ACL-RSI) scale. Functional testing included quadriceps, hamstrings, and gluteal strength testing; Y-balance test; single-leg single hop, crossover hop, and triple hop tests; and timed 6-m hop test. Pearson correlation coefficient and multivariable regression were used to determine associations between the limb symmetry index (LSI) on functional testing and patient-reported outcomes. Those with LSI deficits <20% (better performance) were compared with those with deficits >20% (worse performance).

A total of 229 participants (89 male, 140 female) with a median age of 17 years (range, 10.3-30.6 years) were enrolled. IKDC had a moderate negative correlation with PROMIS - Psychological Stress Experience (r = -0.39; 95% CI = -0.49, -0.27; P < .001) and a moderate positive correlation with ACL-RSI (r = 0.55; 95% CI = 0.46, 0.64; P < .001). A total of 151 patients completed functional testing. ACL-RSI demonstrated a positive correlation with single-hop LSI (r = 0.21; 95% CI = 0.05, 0.35; P = .01) and timed 6-m hop (r = 0.28; 95% CI, 0.42; P = .001). When adjusting for sex, age, and graft type, patients who had <20% deficit on the single-hop test scored 16.6 points higher on ACL-RSI (P = .001), and those with <20% deficit on crossover hop testing scored a mean 13.9 points higher on ACL-RSI (P = .04).

Higher psychological readiness for return to sport was associated with better performance and greater symmetry on hop testing 6 months after ACLR, suggesting a potential link between physical and psychological recovery.

We aimed to report the trajectory of self-reported outcomes up to 11 years post-ACLR. We also explored the relationship between hop performance at 1 year and: (i) future self-reported knee outcomes; and (ii) risk of subsequent knee events. 124 participants (43 women, mean age 31 ± 8 years) were recruited at 1 year following hamstring-autograft ACLR. Hop performance was assessed with single-forward and side-hop tests. Follow-up was completed at 3 (n = 114), 5 (n = 89) and 11 years (n = 72) post-ACLR. Self-reported outcomes were assessed at each follow-up with the Knee injury Osteoarthritis Outcome Score (KOOS) pain and quality of life (QOL) subscales. Generalized linear mixed models estimated the relationship between hop performance and self-reported outcomes. Subsequent knee events (new injury/surgery) to either knee were recorded, with the relationship between hop performance and risk of subsequent knee events analyzed with Cox proportional hazards. Self-reported knee outcomes were stable (mean change < 10 points) across all timepoints but with major within-sample variability. There was a modest relationship between greater hop performance at 1 year and better future KOOS-pain (average marginal effect [AME] % improvement with + 1 cm single forward hop = 0.06% [95% CI 0.02-0.10]). A nonlinear spline relationship showed better single-forward hop performance was associated with better KOOS-QOL for scores < 108 cm, not present for higher hop scores > 108 cm. There were 21 index and 11 contralateral subsequent knee events. Hop performance was not related to risk of a subsequent knee event (hazard ratio index knee 0.99 [95% CI 0.98-1.02]). In conclusion, self-reported knee pain and quality of life were generally stable across the 11-year follow-up period. Greater hop performance at 1-year post-ACLR was related to better self-reported knee outcomes up to 11-year follow-up (of questionable clinical importance), but not associated with the risk of subsequent knee injury/surgery.

Reaching the Patient-Acceptable Symptom State (PASS) threshold for the Knee injury and Osteoarthritis Outcome Score (KOOS) has previously been reported to successfully identify individuals experiencing clinical success after anterior cruciate ligament reconstruction (ACLR). Thus, the objectives of this study were to examine and compare the percentages of patients meeting PASS thresholds for the different KOOS subscales 1 year postoperatively after primary ACLR compared with revision ACLR (rACLR) and multiply revised ACLR (mrACLR), and second, to examine the predictors for reaching PASS for KOOS Quality of Life (QoL) and Function in Sport and Recreation (Sport/Rec) after mrACLR.

Prospective observational registry study.

The data used in this study was obtained from the Swedish National Ligament Registry and collected between 2005 and 2020.

The study sample was divided into three different groups: (1) primary ACLR, (2) rACLR and (3) mrACLR. Data on patient demographic, injury and surgical characteristics were obtained as well as mean 1-year postoperative scores for KOOS subscales and the per cent of patients meeting PASS for each subscale. Additionally, the predictors of reaching PASS for KOOS Sport/Rec, and QoL subscales were evaluated in patients undergoing mrACLR.

Of the 22 928 patients included in the study, 1144 underwent rACLR and 36 underwent mrACLR. Across all KOOS subscales, the percentage of patients meeting PASS thresholds was statistically lower for rACLR compared with primary ACLR (KOOS Symptoms 22.5% vs 32.9%, KOOS Pain 84.9% vs 92.9%, KOOS Activities of Daily Living 23.5% vs 31.4%, KOOS Sport/Rec 26.3% vs 45.6%, KOOS QoL 26.9% vs 51.4%). Percentages of patients reaching PASS thresholds for all KOOS subscales were comparable between patients undergoing rACLR versus mrACLR. No predictive factors were found to be associated with reaching PASS for KOOS QoL and KOOS Sport/Rec 1 year postoperatively after mrACLR.

Patients undergoing ACLR in the revision setting had lower rates of reaching acceptable symptom states for functional knee outcomes than those undergoing primary ACLR.

Prospective observational registry study, level of evidence II.

To determine risk factors for second anterior cruciate ligament (ACL) injury following primary ACL reconstruction (ACLR) using return-to-sport (RTS) tests consisting of qualitative and quantitative measures in young athletes.

A case-control study design was used, and a retrospective review of adolescent athletes after primary ACLR was performed. All athletes completed an RTS test consisting of qualitative and quantitative assessments and psychological assessments with the Tampa Scale of Kinesiophobia. Athlete demographics, surgical characteristics and sports participation were also examined. A binary logistic regression was performed to verify an independent association between risk factors and second ACL injury using adjusted OR (aORs), 95% CI and p<0.05.

In 72 eligible athletes, 12 (16.7%) suffered a second ACL injury. The mean Tegner activity level was 8.4+1.1, and the mean time from ACLR to RTS test completion was 10.4+2.9 months. One variable that showed the lowest p-value in the preliminary analysis was entered into the binary logistic regression model, which resulted in that qualitative assessment of knee valgus during the sidestep cut was associated with second ACL injury (aOR=4.64, 95% CI: 1.18 to 18.23, p=0.03).

Athletes who demonstrated excessive dynamic knee valgus on the involved limb during the sidestep cut were approximately 4.6 times more likely to suffer a second ACL injury.

Bone-patellar tendon-bone (BPTB) autograft size may be one modifiable predictor of anterior cruciate ligament (ACL) reconstruction postoperative success, as smaller graft diameter has been associated with higher rates of rupture requiring revision. However, measuring the true intra-articular tendinous graft diameter of the soft tissue portion of a BPTB graft with standard intraoperative methods is difficult while keeping the graft intact.

The purpose of the study was to use 3-dimensional magnetic resonance imaging (MRI) measurements to determine the cross-sectional area of the soft tissue, tendinous portion of a standard BPTB autograft with 10-mm diameter bone plugs, and, by calculation, the collagen graft size (ie, graft diameter), as would typically be reported in ACL reconstruction studies that consider soft tissue graft size. It was hypothesized that the calculated collagen graft diameter of 10-mm BPTB autografts would be significantly smaller than 10 mm.

Cross-sectional study; Level of evidence, 3.

A total of 100 patients (10 girls and 10 boys at each age from 13 to 17 years) who underwent a knee MRI at a single academic orthopaedic center without documented extensor mechanism pathology were identified. The central 10-mm width of the patellar tendon that would be harvested for BPTB autograft was measured. The region of interest area tool was then used to measure the cross-sectional area of a 10-mm BPTB graft with subsequent soft tissue autograft diameter calculation.

The mean calculated tendinous graft diameter of a 10 mm-wide BPTB graft was 6.3 ± 0.5 mm and was significantly smaller than a 10-mm reference (P≤ .001). There was no significant association between age and cross-sectional area or graft diameter.

Modern 3-dimensional imaging-based measurement techniques demonstrated that the true intra-articular tendinous soft tissue portion of 10-mm BPTB autografts shows substantial variation and is significantly smaller in diameter than the tunnels typically reamed to accommodate the bone plug portions of these grafts. Moreover, as graft size is a predictor of rupture rate, preoperative MRI-based evaluation may be an important tool when considering BPTB autograft for ACL reconstruction. Future comparative clinical research utilizing graft size as a study variable should consider quantifying and utilizing the diameter of the soft tissue component of BPTB autografts.

The anterior cruciate ligament (ACL) is a common knee injury in high-intensity sports, which can cause early career loss in young athletes. Concomitant damage to other knee stabilizers may occur, such as the medial collateral ligament (MCL). Recent studies have shown that knee stability can increase without surgical intervention in patients with ACL and MCL injuries. Regarding the importance of functional tests in return to exercise prediction, this study aims to measure nonsurgical approach's long-term outcome for concomitant ACL and MCL injuries with a focus on functional tests. This is a case-control study with a 2-year follow-up. The case group consisted of patients who had provided written consent and completed their 2-year follow-up, and the control group was made up of healthy people who did not have any knee medical conditions and were matched by age, gender, and activity level. Physical examinations, Tegner and International Knee Documentation Committee questionnaires, and knee magnetic resonance imaging were conducted, and functional performance tests were performed after a 10-minute warm-up. Lody's index (the ratio of injured-to-uninjured knee results) was calculated. The data were analyzed using independent t-test, one-way analysis of variance, chi-squared test, and Fisher's exact test. The study involved 11 patients in each concomitant ACL and MCL injury cases and healthy control groups with a mean age of 32.4 and 28 years, respectively. None of the patients reported knee instability symptoms in the 2-year follow-up. More than half of the patients continued their sports field without reinjury, with no significant difference in activity levels between case and control groups. The 6-meter hop test and single-leg hop test showed no significant difference between case and control groups (p-value: 0.326, 0.859), and no significant difference was observed in the three Carioca, cocontraction, and Shuttle tests in the 2-year follow-up. Functional tests in ACL and MCL injuries revealed normal outcomes, implying a nonsurgical approach for patients with proximal ACL tears, better knee stability, and no significant differences between the injured and control groups.

Bridge-enhanced anterior cruciate ligament restoration (BEAR) combines suture repair of the anterior cruciate ligament (ACL) with an extracellular matrix implant plus autologous blood to facilitate native ACL healing.

The purpose of this study was to compare the 6-year follow-up outcomes of patients who underwent the BEAR procedure with those of a nonrandomized concurrent control group receiving autograft ACL reconstruction (ACLR) in the first-in-human safety study of the BEAR implant (BEAR I trial). Based on the 2-year results, it was hypothesized that isometric hamstring strength after the BEAR procedure would be greater than that after ACLR and that there would be no other differences in outcomes at 6 years.

Cohort study, Level of evidence, 2.

Ten patients underwent BEAR and 10 received ACLR with a 4-stranded hamstring autograft. Outcomes assessed included the record of subsequent surgeries, the International Knee Documentation Committee (IKDC) Subjective Knee Score, IKDC physical examination grade, the Knee injury and Osteoarthritis Outcome Score, instrumented knee laxity, functional outcomes (ie, muscle strength assessments and hop testing), and qualitative magnetic resonance imaging assessment. Comparisons between treatments were based on computations of the mean differences and the associated 95% CIs.

One patient in the BEAR group and 3 patients in the ACLR group were lost to follow-up. In the period between 2 and 6 years, 1 patient in each group underwent revision surgery. There were no differences between groups at the 6-year follow-up in any of the outcome measures except for isometric hamstring strength, which was approximately equal to that of the contralateral knee in the BEAR group and <44% of that in the contralateral knee in the ACLR group (P < .01).

This preliminary study suggests that the outcomes of BEAR and ACLR with a hamstring tendon graft may be similar at the 6-year follow-up and warrants investigation of the BEAR procedure in a larger cohort of patients.

The incidence of anterior cruciate ligament (ACL) injuries in children is on the rise. Despite this trend, the optimal management of these injuries remains a matter of ongoing debate. In this light, our study seeks to assess the clinical, radiological, and functional outcomes of transphyseal ACL reconstruction in preadolescent patients in the medium-term.

This prospective study included preadolescent patients aged up to 12 years who underwent ACL transphyseal reconstruction between 2010 and 2020 and had a minimum follow-up of 2 years. Clinical assessments encompassed joint stability and range of motion. Furthermore, leg length discrepancy (LLD) and femorotibial alignment were evaluated both clinically and radiologically using full-length lower limb standing radiographs. Pre- and postoperative functional outcomes were assessed using the International Knee Documentation Committee (IKDC) and Lysholm scales, and the return to normal sports activity was evaluated using the ACL-Return to Sport after Injury (ACL-RSI) scale. Complications and relevant follow-up data were also recorded. Statistical analyses were conducted to evaluate these outcomes.

A total of 35 preadolescent patients, consisting of 24 males and 11 females, with a mean age at surgery of 11.2 ± 0.7 years (8.7-12), were included in the study. The mean follow-up was 52.3 ± 20.7 months (24.1-95.9). No significant growth disturbances or clinically relevant LLD were evidenced. All patients demonstrated clinically stable knees with full range of motion at the 2-year follow-up. There were statistically significant improvements in pre- and postoperative IKDC (39.3 ± 13.5 vs. 99.7 ± 0.8, p < 0.005) and Lysholm scores (48.2 ± 15.1 vs. 99.6 ± 1.4, p < 0.005). All but two patients were able to return to their pre-injury level of sports activity, with a mean ACL-RSI score of 93.5 ± 1.3. The analysis revealed an 8.6% rerupture rate and an 11.4% rate of contralateral ACL injuries, with 5-year survival rates of 92.3% and 88.8%, respectively. Subgroup analyses based on age, gender, surgical delay, or associated meniscal lesions did not reveal any significant differences in functional outcomes. Additionally, there was no discernible relationship between age or timing of ACL reconstruction and the risk of meniscal injuries.

Our study reinforces the value of ACL reconstruction in skeletally immature preadolescent patients, with transphyseal technique proven to be a safe, effective, and technically simpler option, even for children under the age of 12. The findings indicate excellent functional outcomes, a high rate of successful return to sporting activities, and minimal to no incidence of growth-related complications in the medium-term.

Level II, prospective comparative cohort study, before and after intervention.

Patient-specific risk profiles of clinical failure after anterior cruciate ligament reconstruction (ACLR) are meaningful for preoperative surgical planning and postoperative rehabilitation guidance.

To create an ensemble algorithm machine learning (ML) model and ML-based web-based tool that can predict the patient-specific risk of clinical failure after ACLR.

Cohort study; Level of evidence, 3.

Included were 432 patients (mean age, 26.8 ± 8.4 years; 74.1% male) who underwent anatomic double-bundle ACLR with hamstring tendon autograft between January 2010 and February 2019. The primary outcome was the probability of clinical failure at a minimum 2-year follow-up. The authors included 24 independent variables for feature selection and model development. The data set was split randomly into training sets (75%) and test sets (25%). Models were built using 4 ML algorithms: extreme gradient boosting, random forest, light gradient boosting machine, and adaptive boosting. In addition, a weighted-average voting (WAV) ensemble model was constructed using the ensemble-voting technique to predict clinical failure after ACLR. Concordance (area under the receiver operating characteristic curve [AUC]), calibration, and decision curve analysis were used to evaluate predictive performances of the 5 models.

Clinical failure occurred in 73 of the 432 patients (16.9%). The 8 most important predictors for clinical failure were follow-up period, high-grade preoperative knee laxity, time from injury to ACLR, participation in competitive sports, posterior tibial slope, graft diameter, age at surgery, and medial meniscus resection. The WAV ensemble algorithm achieved the best predictive performance based on concordance (AUC, 0.9139), calibration (calibration intercept, -0.1806; calibration slope, 1.2794; Brier score, 0.0888), and decision curve analysis (greatest net benefits) and was used to develop an web-based application to predict a patient's clinical failure risk of ACLR.

The WAV ensemble algorithm was able to accurately predict patient-specific risk of clinical failure after ACLR. Clinicians and patients can use the web-based application during preoperative consultation to understand individual prediction outcomes.

Nijmeijer, EM, Kempe, M, Elferink-Gemser, MT, and Benjaminse A. Observe, practice and improve? Enhancing sidestep cutting (SSC) execution in talented female soccer players: A four-week intervention program with video instruction. J Strength Cond Res 38(8): e430-e439, 2024-Implicit learning has the potential to improve movement execution and reduce injury risk. Previous research showed beneficial effects of short-term interventions with implicit learning in male athletes. However, research on long-term interventions in female athletes is lacking. The aim of this study was to examine the effects of a 4-week intervention with video instruction on movement execution of SSC, a task that is highly related with anterior cruciate ligament (ACL) injury risk, in female athletes. Twenty talented adolescent female soccer players were part of the control (CTRL, n = 10) or video instruction (VIDEO, n = 10) group. All subjects practiced 4 weeks and received general task instructions. In addition, the VIDEO group received expert video instruction during practice. Lower extremity kinematics and kinetics and vertical ground reaction force of SSC were examined during baseline, immediate post, and 1-week retention tests. After nonlinear registration, differences between each subject and the expert she had seen were determined. These differences were analyzed with SPM1D 2-way ANOVA. No interaction effects between time and group were found ( p > 0.05). Main effects of time were found in the frontal plane. In particular, smaller deviations of subjects compared with the seen expert of the knee adduction ( p = 0.005, 97.9-100% stance phase [SP]) and hip abduction ( p = 0.005, 11.5-13.8% SP) and adduction ( p < 0.001, 33.4-87.7% SP) moments were found in immediate post compared with baseline. These frontal plane short-term improvements, replicating earlier findings in both sexes, may lower ACL injury risk. The large observed interindividual differences over time may have concealed the long-term effects of video instruction at the group level.

During vertebrate embryogenesis, axial tendons develop from the paraxial mesoderm and differentiate through specific developmental stages to reach the syndetome stage. While the main roles of signaling pathways in the earlier stages of the differentiation have been well established, pathway nuances in syndetome specification from the sclerotome stage have yet to be explored. Here, we show stepwise differentiation of human iPSCs to the syndetome stage using chemically defined media and small molecules that were modified based on single cell RNA-sequencing and pathway analysis. We identified a significant population of branching off-target cells differentiating towards a neural phenotype overexpressing Wnt. Further transcriptomics post-addition of a WNT inhibitor at the somite stage and onwards revealed not only total removal of the neural off-target cells, but also increased syndetome induction efficiency. Fine-tuning tendon differentiation in vitro is essential to address the current challenges in developing a successful cell-based tendon therapy.

Anterior cruciate ligament (ALC) tears are increasingly common in skeletally immature patients, as more children and adolescents participate in intensive sports training and specialization at increasingly younger ages. These injuries were historically treated nonoperatively, given concerns for physeal damage and subsequent growth disturbances after traditional ACL reconstruction techniques. However, there is now sufficient data to suggest superior outcomes with operative treatment, specifically with physeal-sparing and physeal-respecting techniques. This article reviews considerations of skeletal maturity in patients with ACL tears, then discusses surgical techniques, with a focus on their unique indications and outcomes. Additional surgical adjuncts and components of postoperative rehabilitation, which may reduce retear rates, are also considered.

Current research shows favorable patient-reported outcomes and high return-to-sport rates after ACL reconstruction in skeletally immature patients. Graft rupture (ACL retear) rates are low, but notably higher than in most adult populations. Historically, there has been insufficient research to comprehensively compare reconstruction techniques used in this patient population. However, thoughtful systematic reviews and multicenter prospective studies are emerging to address this deficit. Also, more recent data suggests the addition of lateral extra-articular procedures and stringent return-to-sports testing may lower retear rates. Physeal-sparing and physeal-respecting ACL reconstructions result in stabilization of the knee, while respecting the growth remaining in children or skeletally immature adolescents. Future research will be essential to compare these techniques, given that more than one may be appropriate for patients of a specific age and skeletal maturity.

Despite increasing use of quadriceps tendon (QT) autograft in anterior cruciate ligament (ACL) reconstruction (ACLR), limited data exist regarding its outcomes in high-risk adolescent athletes.

To (1) report the outcomes after QT ACLR in adolescent athletes and (2) identify patient-related and surgery-related factors that may influence failure rates after QT ACLR.

Case series; Level of evidence, 4.

All patients aged 14 to 17 years who underwent primary anatomic, transphyseal, single-bundle QT ACLR between 2010 and 2021 with a minimum 2-year follow-up were included for analysis. Demographic and surgical data as well as preoperative International Knee Documentation Committee (IKDC) and Marx activity scores were collected retrospectively. All patients were also contacted to assess postoperative patient-reported outcomes (PROs), including IKDC and Marx activity scores, and return-to-sports (RTS) data. Outcomes of interest included rates of revision ACLR and ipsilateral complications, contralateral ACL tears, difference in pre- and postoperative PROs, and rates of RTS. Patient and surgical characteristics were compared between groups who required revision ACLR versus those who did not.

A total of 162 patients met inclusion criteria, of which 89 adolescent athletes (mean age 16.2 ± 1.1 years, 64% female) were included for analysis at mean follow-up of 4.0 years. Postoperative IKDC scores were significantly higher than preoperative scores (88.5 vs 37.5; P < .001), whereas Marx activity scores decreased postoperatively (14.3 vs 12.2; P = .011). Successful RTS occurred in 80% of patients at a mean time of 9.7 ± 6.9 months, and 85% of these patients returned to the same or higher level of sports. The most common reasons for failure to RTS included lack of time (n = 7, 70%) and fearing reinjury in the operative knee (n = 5, 50%). The overall revision ACLR rate was 10% (n = 9), and contralateral ACL tears occurred in 14% (n = 12) of patients. The overall ipsilateral knee reoperation rate was 22.5% (n = 20). No statistically significant differences in patient or surgical characteristics were observed between patients who underwent revision ACLR and those who did not.

At a minimum 2-year follow-up after QT ACLR, adolescent athletes experienced significantly improved postoperative IKDC scores, high rates of RTS, and low rates of graft failure, despite a relatively high ipsilateral reoperation rate. Surgeons may utilize this information when identifying the optimal graft choice for adolescent athletes who have sustained an ACL injury and wish to return to high level of sporting activities.

The treatment of rotational instability has been an intriguing challenge since the era of modern anterior cruciate ligament (ACL) surgery. Lateral extra-articular procedures (LEAPs) have emerged as a solution to this problem, particularly in high-risk populations. Several studies have shown significant benefits of combining LEAPs with ACL reconstruction, including reduced graft failure rates, improved knee stability, improved rotational stability, and higher return-to-play rates. These findings have led to an in-depth evaluation of LEAPs as lateral extra-articular tenodesis and anterolateral ligament reconstruction and their potential role in improving outcomes after ACL reconstruction.

Objective  To evaluate if there is a significant difference in the outcomes of isolated anterior cruciate ligament (ACL) reconstruction in patients with or without associated anterolateral ligament (ALL) injury. Methods  We conducted a retrospective cross-sectional study through the analysis of medical records and the application of the questionnaires of the Lysholm Knee Scoring Scale and the International Knee Documentation Committee (IKDC) Subjective Knee Form to patients undergoing isolated ACL reconstruction. Results  The 52 participants included were divided into two groups: 19 with associated ALL injury and 33 with no associated ALL injury. None of the patients with associated ALL injury suffered an ACL rerupture, and 21.1% presented injuries to other knee structures after surgery. Among the patients with no associated injury, 6.1% suffered ACL rerupture, and 18.2% presented injuries to other structures after surgery ( p  = 0.544). Return to activities at the same level as that of the preoperative period occurred in 60% of the patients with associated ALL injury and in 72% of those with no associated injury ( p  = 0.309). The mean score on the Lysholm Knee Scoring Scale was of 81.6 points in patients with associated ALL injury, and of 90.1 in those with no associated injury ( p  = 0.032). The mean score on the IKDC Subjective Knee Form was of 70.3 points in patients with associated ALL injury and of 76.7 in those with no associated injury ( p  = 0.112). Conclusion  There was no statistically significant difference regarding graft injuries or new injuries to other structures, satisfaction with the operated knee, or the score on the IKDC Subjective Knee Form. Return to activity was similar in the groups with and without associated ALL injuries. The scores on the Lysholm Knee Scoring Scale were better, with a statistically significant difference in the group with no associated ALL injuries.

The objective of this study was to assess the mid-term effectiveness of a return to sport (RTS) test in relation to preventing anterior cruciate ligament (ACL) re-rupture and contralateral ACL injury following ACL reconstruction (ACLR). Furthermore, this study aimed to assess the timing of passing a, RTS-test after surgery, and the effect age has on RTS outcomes.

Patients undergoing ACLR between August 2014 and December 2018 took an RTS-test following rehabilitation. The RTS-test consisted of the Anterior Cruciate Ligament Return to Sport After Injury Scale, a single-leg hop, a single-leg triple hop, a single-leg triple cross-over hop, a box-drop vertical jump down, a single-leg 4-rep max-incline leg press, and a modified agility T test. RTS-passing criteria were ≥90% limb symmetry index in addition to defined takeoff and landing parameters. Mid-term review assessed sporting level, ACL re-injury, and contralateral ACL injury.

A total of 352 patients underwent RTS-testing, following ACLR with 313 (89%) contactable at follow-up, a mean of 50 months (standard deviation: 11.41, range: 28-76) after surgery. The re-rupture rate was 6.6% after passing the RTS-test and 10.3% following failure (p ​= ​0.24), representing a 36% reduction. Contralateral ACL injury rate after surgery was 6% and was 19% lower in those passing the RTS test. The mean age of patients passing their first RTS-test was significantly higher than that of those who failed (p ​= ​0.0027). Re-ruptures in those who passed the RTS test first time occurred late (>34 months), compared to those who failed first time, which all occurred early (<33 months) (p ​= ​0.0015). The mean age of re-rupture was significantly less than those who did not sustain a re-rupture (p ​= ​0.025).

Passing a RTS-test following ACLR reduces ACL re-rupture by 36.21% and contralateral ACL injury by 19.15% at mid-term follow-up. Younger patients are more likely to fail a RTS-test and are at higher risk of contralateral ACL rupture.

To compare physical therapy (PT) utilization, timing of return-to-sport (RTS) test and hop test performance by age and between sexes in youth after anterior cruciate ligament reconstruction (ACLR).

Multicenter retrospective cohort.

A retrospective review of adolescents after primary ACLR was conducted. Participants completed return-to-sport (RTS) tests including single-legged hop testing. PT frequency, average weekly visits, and timing of RTS test were calculated. T-tests assessed the effect of age and sex on average weekly PT visits and multivariable logistic regressions assessed odds of passing hop tests.

289 participants were included (15.7 ± 1.9 years). There was no difference in average weekly PT visits (p = 0.321) or time to RTS test (p = 0.162) by age. There were significant differences in average weekly PT visits (p = 0.047) and mean time from surgery to RTS test (p = 0.048) between sexes with small effect sizes (d = 0.24 and d = 0.21, respectively). Age and sex had no effect on odds of passing hop tests (OR, 1.29; 95% CI, 0.71-2.35 and OR, 0.79; 95%CI, 0.43-1.45, respectively).

In a youth cohort, age and sex may have no clinically important effect on PT visit utilization, timing of RTS test or hop test performance.

Netball is a popular sport worldwide, particularly for women. However, its nature puts players at high risk for anterior cruciate ligament (ACL) injury.

To determine (1) the prevalence of ACL graft rupture and contralateral ACL (CACL) rupture in Australian female netballers after ACL reconstruction (ACLR) and (2) the rate of return to sports (RTS) and psychological readiness.

Cohort study; Level of evidence, 3.

A patient database identified 332 consecutive female netball players who underwent ACLR with hamstring tendon autografts performed by 2 surgeons between 2007 and 2015. Patients were retrospectively surveyed at a minimum of 7 years postoperatively-including details of a second ACL injury to either knee, RTS, and psychological readiness per the ACL-Return to Sport After Injury (ACL-RSI) score. Multivariate regression assessed the association between selected variables and repeat ACL injury.

A total of 267 patients (80%) were included with a mean follow-up of 8.4 years (range, 7-15 years). ACL graft rupture and CACL rupture occurred in 11 (4%) and 27 (10%) patients, respectively, at 7 years postoperatively. The ACL graft had a survival rate of 99%, 97%, 97%, and 96% at 1, 2, 5, and 7 years after surgery, respectively. The native CACL had a survival rate of 100%, 99%, 94%, and 90% at 1, 2, 5, and 7 years, respectively. Adolescents had a 4.5 times greater hazard for ACL graft rupture (95% CI, 1.4-14.6; P = .014) and a 2.5 times greater hazard for CACL rupture (95% CI, 1.2-5.5; P = .021) compared with adults. CACL injury was also associated with a return to level 1-including jumping, hard pivoting, and cutting-sports (hazard ratio, 10.3 [95% CI, 1.4-77.1]; P = .023). Most (62%) participants returned to netball, with those with higher ACL-RSI scores more likely to RTS.

The prevalence of repeat ACL injury was higher in the contralateral knee (10%) than the ACL-reconstructed knee (4%) at 7 years postoperatively. ACLR was a suitable option for female netballers who sustained an ACL rupture with low long-term rates of graft rupture. Repeat ACL injuries to either knee were more common in adolescents and those who returned to cutting and pivoting sports.

The objective of this study is to investigate the risk of revision surgery when delaying anterior cruciate ligament reconstruction (ACLR) past 3 months or 6 months after injury.

A total of 30,280 patients with isolated ACLR were identified in the Danish Knee Ligament Reconstruction Registry and divided into four groups; ACLR < 3 months, > 3 months, < 6 months, or > 6 months after injury. Primary outcome was revision surgery and secondary outcome were objective and subjective clinical outcome. The 2 year relative risk, crude, and adjusted hazard ratio (HR) were calculated.

Comparing ACLR < 3 months to ACLR > 3 months of injury the 2 year relative risk of revision surgery was found to be 1.81 (95% CI 1.46-2.23; P < 0.001) with an adjusted hazard ratio (HR) of 1.27 (95% CI 1.12-1.44; P < 0.001). Comparing ACLR < 6 months to ACLR > 6 months of injury the 2 year relative risk of revision surgery was found to be 1.61 (95% CI 1.34-1.92; P < 0.001) with an adjusted HR of 1.27 (95% CI 1.15-1.40; P < 0.001).

The risk of revision ACLR surgery was found to be increased when ACLR was performed within 3 months or 6 months of injury compared with later surgery. The 1 year postoperative objective knee laxity and the subjective patient-related outcome was found to be without a clinically significant difference; however, those with early ACLR (< 3 months or < 6 months) were found to have a higher activity level 1 year postoperatively. The information about increased risk of revision when having early surgery should be informed to patients when deciding timing of ACLR treatment.

II.