Knee muscle strength recovery after anterior cruciate ligament reconstruction (ACLR) is crucial for a safe return to sport (RTS) but it is poorly described in the adolescent population. Therefore, we compared the knee muscle strength at 6 months post-surgery in adults and adolescents. We hypothesized a greater muscular strength in adolescents 6 months after ACLR.

This was a retrospective analysis of 55 adolescents (13-18 years old) and 76 adults (19-39 years old) who underwent ACLR with autograft bone-patellar-tendon-bone (BPTB), subjected to isokinetic tests 6 months after surgery. The following outcomes were analyzed: (1) the maximum torque of hamstrings (H) and quadriceps (Q) during flexion and extension at 30°/s normalized by body weight; (2) hamstrings to quadriceps strength ratio (HQ ratio); (3) injured to uninjured leg muscle strength ratio (limb-symmetry index, LSI).

Both adults and adolescents produced lower Q torque with the injured leg compared with uninjured, but similar H torque. In adolescents, the injured Q torque and the Q-LSI were higher compared with adults. In both populations, the Q-LSI was lower than the H-LSI and the HQ ratio in the injured leg was higher compared with uninjured. Adolescents showed a lower HQ ratio in injured legs.

At 6 months after ACLR both adolescents and adults did not recover Q strength in the injured leg. However, adolescents showed larger Q strength compared with adults. The HQ ratio analysis showed that 6 months after surgery both groups are not ready for a safe RTS.

Knee muscle strength recovery after anterior cruciate ligament reconstruction is usually evaluated using isokinetic Limb Symmetry Index to help take the decision to allow return to the previous sport. However, the role of age on knee strength recovery is not well known. So, we aimed to compare the isokinetic knee muscle strength recovery according to age at 4 and 7 months after anterior cruciate ligament reconstruction using hamstring graft.

From a historical cohort (2018-2023) of patients who completed isokinetic monitoring at 4 and 7 months after anterior cruciate ligament reconstruction using hamstring graft, two groups were compared according to age: ≤19 and >20 years old. The Quadriceps and Hamstring Limb Symmetry Indexes were studied as the main parameters. A multivariate analysis was realized to assess the weight of potential inter-subject explanatory parameters on knee strength evolution.

253 adolescents were compared to 247 adults. The adolescent Quadriceps Symmetry Index at 60°/s was significantly higher than that of adults (79% vs 72%, and 88% vs 82% at 4 and 7 months of follow-up, respectively). The Hamstring Symmetry Index was not statistically significantly different. No inter-subject explanatory parameters were found after the multivariate analysis.

Knee strength recovers faster in adolescents than in adults after anterior cruciate ligament reconstruction using hamstring graft. This result should be carefully considered because adolescents could be exposed to return to sport too early, while the risk of graft rupture is still high, if strength cutoff is only considered.

III.

In Australia, few people with acute anterior cruciate ligament (ACL) rupture are managed with rehabilitation alone despite clinical trials demonstrating similar outcomes to ACL reconstruction (ACLR). The reasons for the low uptake of rehabilitation alone for the treatment of acute ACL rupture in Australia are unclear.

The objectives of this study were to evaluate physical therapists' beliefs and the information they provide to patients about treatment options for ACL rupture, and to explore ACL rupture treatment decision-making from the perspective of physical therapists.

The design was a mixed-methods convergent parallel design comprising an Australia-wide survey (n = 246) and semi-structured interviews (n = 10).

Participants included physical therapists who manage people with ACL rupture in Australia.

The survey contained 41 items that assessed demographics, treatment of ACL rupture, referral pathways, treatment beliefs, and the information provided to patients with ACL rupture.

Physical therapists' beliefs about treatment options varied and did not always reflect the information they provided to patients. Although 60% agreed that ACLR and rehabilitation-alone result in similar outcomes on average, only 37% reported regularly informing patients about this. To return to pivoting/contact sport, 23% believed that ACLR was required and 79% informed patients that ACLR was the best treatment to do so. Physical therapists felt that rehabilitation-alone is underutilized as a treatment for ACL rupture. Physical therapists encountered barriers to offering and providing rehabilitation-alone for ACL rupture, reflected in 7 qualitative themes: preference for surgery reflecting societal beliefs; more weight given to surgeon's opinion; unbalanced information from surgeon; referral pathways; uncertain recovery timeline; beliefs about treatment suitability; and knowledge and experience.

Physical therapists had mixed beliefs about treatment options and the information provided to patients was not always evidence based. Physical therapists felt that nonsurgical management was underutilized, and experienced barriers to offering and providing non-surgical management of ACL rupture in clinical practice.

Informed decision-making can only occur if accurate, evidence-based information about ACL rupture treatment options is provided to patients. These findings may be used to guide professional development for physical therapists and inform strategies to improve evidence uptake by physical therapists.

The aim of this study was to evaluate the influence of age on early to mid-term clinical outcomes after anterior cruciate ligament (ACL) reconstruction.

Longitudinal observational study.

Anterior cruciate ligament rupture is often a debilitating condition requiring surgery to restore joint stability. Patient-reported outcome measures (PROMs) can be used to assess knee function after ACL reconstruction. Outcomes from this type of surgery are thought to be influenced by demographic factors such as age.

Subjects undergoing ACL reconstruction were allocated to either the Younger Group (<40 years) or the Older Group (≥40 years).

Arthroscopic primary, anatomic single bundle ACL reconstruction using either middle third bone-patella tendon-bone autograft or quadrupled hamstring tendon (gracillis and semitendinosus) autograft.

Six PROMs were collected before and after ACL reconstruction that included the Knee Injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee (IKDC), Lysholm, Tegner, EuroQol-5 Dimension-5 Level, and Short Form 12-item Health Survey.

A total of 87 patients were included in the study with a mean postoperative follow-up of 2.3 years (range 1-7 years). Preoperatively, the Younger Group had significantly better KOOS pain (P = 0.007), KOOS activities of daily living (P < 0.001), KOOS overall (P = 0.017), IKDC (P = 0.005), Lysholm (P = 0.015), Tegner (P < 0.001), and 12-item Short Form survey physical component summary (P = 0.001) than the Older Group. However, postoperatively only the Tegner (P < 0.001) was significantly better in the Younger Group, while all other scores were comparable. Overall, PROMs had very little correlation with age after surgery.

Older patients with ACL instability have just as much to gain as younger patients from surgical intervention. Therefore, age should not be a contraindication to ACL reconstruction.

To identify independent risk factors for preoperative lower limb venous thrombosis (LLVT) in knee ligament injuries and to develop a diagnostic prediction model based on these factors.

Patients with knee ligament injuries who presented to our hospital between July 2021 and December 2023 were included in this study. Logistic regression analysis was utilized to determine independent risk factors for preoperative LLVT in knee ligament injuries and to construct a diagnostic prediction model. The diagnostic performance of the model was evaluated using receiver operating characteristic curves (ROC) and calibration curves.

Compared with the None-LLVT group, the LLVT group showed statistically significant differences in age, gender, damaged ligament site, injury-examination time, low density lipoprotein (LDL), glucose (G), D-dimer, and fibrinogen degradation products (FDP) (P < 0.05). Multivariate logistic regression analysis showed that gender (P = 0.006, 95% CI [1.647-19.450]), damaged ligament site (P = 0.016, 95% CI [1.385-23.060]), and D-dimer > 0.55 mg/L (P < 0.001, 95% CI [3.029-37.845]) were independent risk factors for preoperative LLVT in patients with knee ligament invasion. The ROC showed good diagnostic efficacy, with an area under the curve (AUC) of 0.888, and the calibration curves showed good agreement (mean absolute error = 0.013).

Gender, damaged ligament site, and D-dimer level can be used as independent risk factors for the preoperative prediction of LLVT, and the nomogram model proposed in this study can better assist clinicians in making clinical decisions.

Background and objectivesTo explore the physical therapists' (PTs) perspectives and clinical practice on assessment, rehabilitation, and return to sports (RTS) criteria and to investigate their associations with gender, level of educational qualification, years of clinical experience, and the number of individuals treated after ACL injury and reconstruction (ACLR) in Saudi Arabia (SA).MethodsThis descriptive cross-sectional study surveyed 206 participants through an online survey covering demographics, ACLR rehabilitation importance, clinical measurements, practice, progression criteria, return to running, and RTS.ResultsMost PTs (84.9%) see an individual post-ACLR for the first time within the first week. About 24.8% of PTs preferred starting open kinetic chain (OKC) exercises one to seven days immediately post-ACLR. The timing of returning to running post-ACLR is variable among participants. Between six to nine months, 39.8% of PTs allowed an individual post-ACLR to RTS. Over 40% of participants did not use patient-reported outcome measures (PROMs) to clear an individual post-ACLR to RTS or evaluate psychological readiness. About 76.2% recommended an ACL injury prevention program at discharge.ConclusionMost PTs in SA inconsistently follow evidence-based ACLR rehabilitation practices. Education and training programs are needed to bridge the evidence-to-practice gap in post-ACLR care.

Anterior cruciate ligament (ACL) rupture is increasingly common in paediatric and adolescent populations, typically requiring surgical ACL reconstruction (ACLR) to restore knee stability. However, ACLR substantially alters knee biomechanics (e.g., motion and tissue mechanics) placing the patient at elevated risk of early-onset knee osteoarthritis.

This study employed a linked neuromusculoskeletal (NMSK)-finite element (FE) model to determine effects of four critical ACLR surgical parameters (graft type, size, location and pre-tension) on tibial articular cartilage stresses in three paediatric knees of different sizes during walking. Optimal surgical combinations were defined by minimal kinematic and tibial cartilage stress deviations in comparison to a corresponding intact healthy knee, with substantial deviations defined by normalized root mean square error (nRMSE) > 10%.

Results showed unique trends of principal stress deviations across knee sizes with small knee showing least deviation from intact knee, followed by large- and medium-sized knees. The nRMSE values for cartilage stresses displayed notable variability across different knees. Surgical combination yielding the highest nRMSE in comparison to the one with lowest nRMSE resulted in an increase of maximum principal stress on the medial tibial cartilage by 18.0%, 6.0% and 1.2% for small, medium and large knees, respectively. Similarly, there was an increase of maximum principal stress on lateral tibial cartilage by 11.2%, 4.1% and 12.7% for small, medium and large knees, respectively. Knee phenotype and NMSK factors contributed to deviations in knee kinematics and tibial cartilage stresses. Although optimal surgical configurations were found for each knee size, no generalizable trends emerged emphasizing the subject-specific nature of the knee and neuromuscular system.

Study findings underscore subject-specific complexities in ACLR biomechanics, necessitating personalized surgical planning for effective restoration of native motion and tissue mechanics. Future research should expand investigations to include a broader spectrum of subject-specific factors to advance personalized surgical planning.

Level III.

A growing body of evidence surrounds secondary meniscal and cartilage pathology after delay to anterior cruciate ligament (ACL) reconstruction (ACLR). Many of these studies focus on or include an adult population.

To elucidate the prevalence of secondary meniscal and chondral pathology with delay to ACLR in the adolescent population as well as examine the influence of sex, skeletal maturity, and trends over the years.

Cohort study; Level of evidence, 3.

A prospective database was used to identify all patients younger than 19 years who underwent ACLR at the authors' center between January 1993 and April 2023. Operative data including meniscal and chondral injury and treatment were prospectively recorded at the time of ACLR. A retrospective analysis was performed assessing the relationship between meniscal treatment and chondral injury at ACLR and the time from injury to ACLR, controlling for age, sex, and decade of surgery with multiple regression analysis. Prevalence of meniscal and chondral surgery at ACLR was examined over time and compared between sexes and age groups.

A total of 2740 patients were identified with a median age of 17 years (range, 7-19 years). Surgical delay of 5 to 12 months increased the risk of medial meniscal tear requiring surgery by 1.6 (95% CI, 1.1-2.2; P = .007). Surgical delay >12 months increased the risk of medial meniscal tear requiring surgery by 4.2 (95% CI, 3.1-5.8; P = .001) and medial chondral injury by 3.4 (95% CI, 2.2-5.1; P = .001). The repairability of medial meniscal tears decreased with greater delay to reconstruction (57% before 5 months vs 19% after 12 months; P = .001). Lateral meniscal tear repairability followed a similar trend. More male than female participants had secondary pathology (46% vs 39%; P = .001). Patients aged 14-19 years had more meniscal surgery and chondral pathology compared with those younger than 14 years (45% vs 30%, P = .001).

Surgical delay >4 months from injury is associated with a steady increase in the prevalence of medial meniscal and chondral pathology in adolescents with ACL rupture. If ACL surgery is delayed >12 months, the odds of requiring medial meniscal surgery is increased by a factor of 4 and the odds of having a chondral lesion is increased by a factor of 3. Timely diagnosis of ACL injury and early surgical referral are important for reducing the odds of meniscal and chondral pathology in adolescents.

Anterior cruciate ligament (ACL) injuries are a major problem in the pediatric and adolescent populations. Some of these injuries are only partial; yet, there is limited data to inform clinical treatment of such partial tears. It is unknown how injury partial injury impacts long-term degenerative changes in the joint relative to complete injury. In this study, we hypothesized that partial (anteromedial (AM) or posterolateral (PL) bundle) tears would result in small levels of instability and degeneration relative to complete ACL tears and that the degree of degeneration would associate with joint instability.

Partial (isolated AM or PL bundle) or complete ACL injury was arthroscopically created in 3-month-old juvenile pigs. The contralateral limb served as a sham-operated control. Six months after injury, joint biomechanics was assessed along with cartilage and meniscus degeneration (via magnetic resonance imaging [MRI], gross imaging, and histology).

Joint laxity increases were minimal after PL bundle injury (difference relative to controls (confidence interval): 0.5 (-1.2-2.2) mm), minor after AM bundle injury (3.7 (2.0-5.4) mm), and major after ACL injury (15.8 (13.7-17.8) mm). Cartilage MRI T1ρ relaxation times increased minimally after PL bundle injury (-0.9 (-5.1-3.3) ms for lateral tibia), moderately after AM bundle injury (6.6 (1.7-11.4) ms), and substantially after ACL injury (10.8 (2.1-19.5) ms). Changes in meniscus volume followed a similar rank order. Degeneration was associated with the extent of joint destabilization.

These findings suggest that cartilage and meniscus degeneration in the skeletally immature joint are associated with joint laxity after partial and complete ACL injuries.

This study focuses on the development of the Cambridge Knee Injury Tool (CamKIT), a clinical prediction tool developed as a 12-point scoring tool based on a modified e-Delphi study.

A retrospective cohort evaluation was conducted involving 229 patients presenting to a Major Trauma Centre with acute knee pain over 3 months. The evaluation extracted data on the 12 scoring tool variables as well as diagnostic and management pathway outcomes. CamKIT scores for the injured and non-injured cohorts were then calculated and evaluated.

The CamKIT yielded a median score of 7.5 (IQR: 6-9) in the injured cohort, compared with a median score of 2 (IQR: 1-4) in the non-injured cohort, with a statistically significant difference (p<0.0001). When constructed as a three-tier risk stratification tool, the CamKIT produces a sensitivity of 100%, a specificity of 94.3%, a positive predictive value of 89% and a negative predictive value of 100% for diagnosing clinically significant soft tissue knee injuries.

The CamKIT provides a non-invasive tool that has the potential to streamline the diagnostic process and empower healthcare workers in resource-stretched settings by instilling confidence and promoting accuracy in clinical decision-making. The CamKIT also has the potential to support efficiency in the secondary healthcare setting by enabling more targeted and timely use of specialist resources. This research contributes to the ongoing efforts to enhance patient outcomes and the overall quality of care in managing acute knee injuries.

To investigate kneeling tolerance in patients undergoing hamstring (HT) versus quadriceps (QT) anterior cruciate ligament reconstruction (ACLR) and investigate correlation with patient-reported outcome measures (PROMs).

After recruitment and randomisation, 112 patients (HT = 55; QT = 57) underwent ACLR. Patients were assessed at 6, 12 and 24 months using the Kneeling Tolerance Test, which evaluates patient-reported pain in a position of both 90 (KT90) and 110 (KT110) degrees of knee flexion. PROMs collected included the International Knee Documentation Committee (IKDC) questionnaire and the ACL Return to Sport after Injury (ACL-RSI) questionnaire.

Kneeling tolerance at KT90 and KT110 improved (p < 0.05) for both graft types across all time points. There was no difference in KT90 scores between groups at 6 or 12 months. At 24 months, kneeling tolerance was superior in the QT group (mean HT 93 ± 9 vs. QT 98 ± 5; p = 0.003). For KT110 scores, a statistically significant difference was noted at 6 (mean HT 80 ± 25 vs. QT 89 ± 12; p = 0.027), 12 (mean HT 90 ± 13 vs. QT 95 ± 10; p = 0.040) and 24 months (mean HT 92 ± 10 vs. QT 97 ± 5; p = 0.003). The ACL-RSI was significantly correlated with KT90 and KT110 at 24 months (r = 0.40, p < 0.001; r = 0.40, p < 0.001). Other PROMs demonstrated significant weak-to-moderate correlations with kneeling tolerance.

Patients undergoing ACLR with a QT versus HT autograft report superior kneeling tolerance up to 2 years postsurgery, more prominent in deeper (110°) knee flexion. A strong correlation with ACL-RSI was demonstrated at 2 years.

ACTRN12618001520224p (Australian New Zealand Clinical Trials Registry).

Level 1.

The increased rate of anterior cruciate ligament (ACL) tears has led to a greater number of revisions. Revision surgery can be performed in one or two stages. Single-stage revision ACL reconstruction (ssRACLR) may be performed when prior tunnels can be re-used or bypassed whereas a two-stage procedure is indicated when bone grafting of dilated tunnels prior to revision is necessary. While both approaches have shown similar functional outcomes and failure risk, ssRACLR is preferred, when possible, to avoid the increased morbidity, inconvenience and cost associated with two-stage RACLR. In adequately planning for RACLR, a surgeon should investigate the mechanism and timing of injury as well as the previous graft selection, associated pathology and the tunnel placement and size. It is especially important to obtain radiographs and three-dimensional imaging including magnetic resonance imaging (MRI) and computed tomography (CT), which allow the surgeon to accurately evaluate the entire tunnel architecture to determine surgical staging. Following a detailed assessment of the pathoanatomy, the surgeon may determine graft and hardware type, tunnel placement and utilization of lateral extra-articular tenodesis (LET) and other procedures. In our experience, ssRACLR can be carried out for over 90% of revision cases with creative pre-operative planning using autograft with bone plug(s), divergent tunnel creation on the femur (when necessary) and convergent tunnel creation on the tibia (when appropriate) and suspensory or interference fixation as needed. In revision scenarios, we believe that autografts with bone plugs provide the best opportunity for graft healing and incorporation and that LET can be a useful adjunct to reduce re-tear rates. The purpose of this review is to report on the preoperative considerations and surgical techniques for performing ssRACLR, as well as the outcomes.

Level V expert opinion.

The assessment of performance during functional tasks and the quality of movement execution are crucial metrics in the rehabilitation of patients with anterior cruciate ligament (ACL) injuries. While measuring performance is feasible in clinical practice, quantifying joint kinematics poses greater challenges. The aim of this study was to investigate whether smartphone video, using deep neural networks for human pose detection, can enable the clinicians not only to measure performance in functional tasks but also to assess joint kinematics.

Twelve healthy participants performed the forward reach of the Star Excursion Balance Test 10 times, along with 10 repetitions of forward jumps and vertical jumps, with simultaneous motion capture via a marker-based reference system and a smartphone. OpenPifPaf was utilized for markerless detection of anatomical landmarks in video recordings. The OpenPifPaf coordinates were scaled using anthropometric data of the thigh, and task performance and joint kinematics were computed for both the marker-based and markerless systems.

Comparing results for marker-based and markerless systems revealed similar joint angles, with mean root mean square errors of 2.8° for the knee, 3.1° for the hip, and 3.9° for the ankle. Excellent agreement was observed for clinically pertinent parameters, i.e., the performance, the peak knee flexion, and the knee range of motion (intraclass correlation coefficient > 0.97).

The results underscore the feasibility of using markerless methods based on OpenPifPaf for assessing performance and joint kinematics in functional tasks crucial for ACL patients' rehabilitation. The simplicity of this approach makes it suitable for integration into clinical practice.

This systematic review and meta-analysis aimed to identify the association between genetic polymorphisms and tendon and ligament injuries in adolescent and adult athletes of multiple competition sports. The PubMed, Web of Science, EBSCO, Cochrane Library, and MEDLINE databases were searched until July 7, 2023. Eligible articles included genetic studies on tendon and ligament injuries and comparisons between injured and non-injured athletes. This review included 31 articles, comprising 1,687 injury cases and 2,227 controls, from a meta-analysis of 12 articles. We identified 144 candidate gene polymorphisms (only single nucleotide polymorphisms were identified). The meta-analyses included vascular endothelial growth factor A (VEGFA) rs699947, collagen type I alpha 1 rs1800012, collagen type V alpha 1 rs12722, and matrix metalloproteinase 3 rs679620. The VEGFA rs699947 polymorphism showed a lower risk of injuries in athletes with the C allele ([C vs. A]: OR=0.80, 95% CI: 0.65-0.98, I 2 =3.82%, p=0.03). The risk of these injuries were not affected by other polymorphisms. In conclusion, the VEGFA rs699947 polymorphism is associated with the risk of tendon and ligament injuries in athletes. This study provides insights into genetic variations that contribute to our understanding of the risk factors for such injuries in athletes.

A robust comparison of the recovery pathway between sexes after anterior cruciate ligament reconstruction (ACLR) is lacking. This study investigated sex-based differences in physical and psychological recovery, and return to sport (RTS), after ACLR.

104 community-level patients underwent ACLR. Patients were evaluated at 6-, 12- and 24-months with the Anterior Cruciate Ligament Return to Sport after Injury Scale (ACL-RSI), International Knee Documentation Committee (IKDC) form and Tegner Activity Scale (TAS), a 4-hop test battery including the 6-meter timed hop (6MTH) and the single (SHD), triple (THD) and triple crossover (TCHD) hop tests for distance, and peak isokinetic knee extensor and flexor torque. Sex-based differences were assessed, while regression analysis modelled the relationship between patient characteristics and outcomes, with 24-month psychological readiness to RTS.

All PROMS improved (p < 0.05), with males reporting higher 24-month ACL-RSI (p = 0.002), IKDC (p = 0.007) and TAS (p = 0.005) scores. A greater percentage of males returned to pivoting sports at 24 months (p = 0.030, males 60.0%, females 40.8%). Males demonstrated higher knee extensor strength LSIs at 6 (p = 0.037) and 24 (p = 0.047) months, and higher knee flexor strength LSIs at 6 (p = 0.007) and 12 (p = 0.002) months. IKDC knee scores (β = 24.9; 95% CI, 10.8 to 35.0), male sex (β = 12.2; 95% CI, 3.9 to 20.4) and the 6MTH LSI (β = 1.31; 95% CI, 0.6 to 2.1) were associated with the ACL-RSI.

In community-level ACLR patients, females demonstrated lower physical performance recovery, subjective function and psychological readiness, as well as a lower rate of RTS.

This study aimed to investigate the current beliefs and practices among Australian physiotherapists regarding the management of anterior cruciate ligament (ACL) injuries.

Cross-sectional survey.

Online survey.

Australian physiotherapists.

The survey assessed beliefs and practices regarding non-operative management, ACL reconstruction, pre- and post-operative rehabilitation, and return to sport (RTS) criteria. Frequencies and percentages summarized survey responses, and chi-square or Fisher's exact tests assessed whether beliefs and practices were influenced by experience (≤6 years or >6 years) and annual caseload (<6 or ≥6 patients).

In total, 419 physiotherapists were included, with 367 completing the survey in its entirety. Most physiotherapists (86.8%) consider non-surgical management alternatives for patients. Two-thirds (59.8%) recommend a minimum of 9-12 months before RTS, emphasizing recovery of knee strength (93.9%) and psychological readiness (93.9%). Of those who assessed strength, 32.5% use manual muscle testing, and 37.4% assess strength from hop testing. The 63.5% of respondents who reported barriers to implementing best practice ACL management, cited lack of resources (69.1%) and patient non-compliance (67.8%) as the most common reasons.

This survey of Australian physiotherapists showed alignment with evidence-based ACL guidelines but highlighted differences from international practices and variations by experience and caseload.

Historically, anterior cruciate ligament (ACL) ruptures in the paediatric age group were managed conservatively with bracing, casting, activity modification, and physical therapy. However, most of these patients had to reduce their sports activities, and secondary damages to the affected knee were prevalent.

Published scientific literature in Embase, Web of Science, PubMed, and Google Scholar databases.

ACL reconstruction in children with open physes patients is debated. Any damage to the physes around the knee could lead to growth abnormalities and axial deviation of the knee.

Different grafts are available and suitable for ACL reconstruction in skeletally immature patients; however, which graft performs better remains unclear.

This systematic review compared bone-patellar tendon-bone (BPTB), hamstring tendon (HT), and quadriceps tendon (QT) autografts for ACL reconstruction in skeletally immature patients. The joint laxity, Patient-reported outcome measures (PROMs), return to sport, and complications were compared.

In skeletally immature patients, HT, BPTB, and QT autografts for ACL reconstruction yielded good outcomes. Comparative studies are strongly required to establish the most suitable autograft.

Patients with anterior cruciate ligament reconstruction frequently present asymmetries in the sagittal plane dynamics when performing single leg jumps but their assessment is inaccessible to health-care professionals as it requires a complex and expensive system. With the development of deep learning methods for human pose detection, kinematics can be quantified based on a video and this study aimed to investigate whether a relatively simple 2D multibody model could predict relevant dynamic biomarkers based on the kinematics using inverse dynamics. Six participants performed ten vertical and forward single leg hops while the kinematics and the ground reaction force "GRF" were captured using an optoelectronic system coupled with a force platform. The participants are modelled by a seven rigid bodies system and the sagittal plane kinematics was used as model input. Model outputs were compared to values measured by the force platform using intraclass correlation coefficients for seven outcomes: the peak vertical and antero-posterior GRFs and the impulses during the propulsion and landing phases and the loading ratio. The model reliability is either good or excellent for all outcomes (0,845 ≤ ICC ≤ 0.987). The study results are promising for deploying the developed model following a kinematics analysis based on a video. This could enable clinicians to assess their patients' jumps more effectively using video recordings made with widely available smartphones, even outside the laboratory.

Anterior cruciate ligament (ACL) injury is a significant orthopedic issue globally with varying success rates among different populations. Better understanding of functional outcome can help design suitable protocols for ACL reconstruction and recovery. This review aims to evaluate the epidemiological trends and functional outcomes of ACLR procedures in India.

The review was conducted following PRISMA guidelines, by searching in Google Scholar, Pubmed, Web of Science and Science Direct databases in February 2024. The study encompassed patient demographics, and postoperative outcomes in Indian populations upon ACLR using hamstring tendon autografts. Meta-analysis was conducted with RevMan 5.4 using random-effects models. Funnel plots were used to explore publication bias. Subgroup analyses of follow-up terms and age were also performed.

A total of 26 studies were pooled for overall qualitative and quantitative analysis. Sports injuries (52 %) were found to be more common, followed by road traffic accidents (31 %). Injuries were mostly on the right knees (56 %). Functional outcome analysis using Lysholm Knee Scoring Scale (MD 34.74, 95 % CI 31.58 to 37.89), International Knee Documentation Committee (MD 36.74, 95 % CI 32.36 to 41.13), Tegner Activity Scale (MD 0.90, 95 % CI -0.01 to 1.80) revealed statistically significant overall outcome effect. Statistically non-significant differences were found between follow-up to 6 months and follow-up above 6 months as well as with age. However, meta-analysis showed high level of heterogeneity.

ACLR in Indian population is largely successful in restoring functional activity. However, the outcome of this review is limited by the heterogeneity factor. Further, the Indian studies have not focused on factors affecting the outcome. Therefore, future studies in this direction are needed for understanding the clinical success.

This study aimed to investigate the microstructural and mechanical properties of semitendinosus tendon graft tissues during anterior cruciate ligament reconstruction and the clinical outcomes in skeletally immature and mature patients.

Twenty-two patients who underwent primary anterior cruciate ligament reconstruction using a hamstring tendon graft were analyzed and divided into skeletally immature (n = 7) and mature groups (n = 15) based on magnetic resonance imaging findings of the epiphyseal plate of the distal femur. Tissue samples were collected from the mid-portion of the semitendinosus tendon. The collagen fibril diameter, maximum stress, and strain at maximum stress point in the semitendinosus tendon tissues were calculated for comparison of the microstructural and mechanical properties between the two groups. Postoperative outcomes were also assessed between the two groups.

The mean and 60th and 80th percentiles of fibril diameters in the skeletally immature group were significantly smaller than those in the mature group (65.9 ± 13.0, 73.5 ± 19.3, and 91.3 ± 27.4 nm in the skeletally immature group; and 90.3 ± 14.7, 94.0 ± 18.4, and 125.3 ± 19.9 nm in the skeletally immature group; p = 0.001, 0.024, and 0.004, respectively). Additionally, the strain at maximum stress was higher in the skeletally immature group (237.2 ± 102.4% vs. 121.5 ± 51.9%, p = 0.024). However, there was no difference in maximum stress between the skeletally immature and mature groups (19.9 ± 14.3 MPa vs. 24.5 ± 23.4 MPa, p = 0.578). Strain was negatively correlated with the mean fibril diameter and the 60th and 80th percentiles of fibril diameters, whereas stress was positively correlated with the mean fibril diameter. The skeletally immature group had a higher pivot shift test-positive rate than the mature group at the last follow-up (p = 0.023).

Semitendinosus tendon graft tissues differed microstructurally and mechanically between skeletally immature and mature patients.

Level Ⅳ.

To evaluate and compare the subjective knee function in patients undergoing revision and bilateral anterior cruciate ligament (ACL) reconstruction (ACLR) with those undergoing primary ACLR in a large cohort.

Patients without concomitant ligament injuries who underwent primary, revision or bilateral ACLR at the Capio Artro Clinic, Stockholm, Sweden, between 2005 and 2018 were identified. The Knee injury and Osteoarthritis Outcome Score (KOOS) was collected preoperatively and at 1, 2 and 5 years postoperatively from the Swedish National Knee Ligament Registry. Patients who underwent revision and bilateral ACLR were compared with those who underwent primary ACLR (control group) using Student's t test.

A total of 6831 patients (6102 with primary ACLRs, 343 with revision ACLRs and 386 with bilateral ACLRs) were included. Preoperatively, there were significant but nonclinically relevant differences in favour of the revision ACLR group for KOOS Symptoms, Pain, Activities of Daily Living (ADL) and Sport/Rec subscale scores compared with the primary ACLR group. Postoperatively, except for the 1-year Symptoms and ADL subscales, the revision ACLR group reported significantly lower scores on all KOOS subscales than the primary ACLR group, with clinically relevant differences (>8-10 points) for the 1-, 2- and 5-year Sport/Rec and Quality of Life (QOL) subscales. The bilateral ACLR group reported significantly, but not clinically relevant, inferior scores on the 1-year Symptoms and QOL subscales and the 5-year Sport/Rec and QOL subscales compared with the primary ACLR group.

Revision ACLR, but not bilateral ACLR, was associated with clinically relevant inferior subjective knee function compared with primary ACLR. It is important to counsel patients regarding their future subjective knee function after repeated ACLR. Compared to primary ACLR, inferior subjective results should be expected after revision ACLR, but not after bilateral ACLR.

Level III.

Posterior tibial slope (PTS) has been identified as a possible modifiable risk factor for anterior cruciate ligament (ACL) injury and ACL reconstruction (ACLR) failure. However, the findings in the literature are inconsistent. This may be explained by several different reasons, including different measurement methods, differing definitions of ACLR failure, and possible inclusion of suboptimal films.

To compare PTS values obtained using plain radiographs (XR-PTS) in a young (≤21 years of age), skeletally mature patient population with those obtained using magnetic resonance imaging (MRI), as well as to quantify the number of suboptimal lateral knee radiographs obtained across an integrated health care system and determine the potential effect of including these radiographs on summary statistics of XR-PTS.

Case-control study; Level of evidence, 3.

Skeletally mature adolescent and young adult patients ≤21 years of age were identified from the ACLR registry of Kaiser Permanente. The cases of concern were patients requiring revision ACLR. The controls were patients who had an ACLR and did not require a revision procedure. The XR-PTS measurements were made on plain radiographs by a single blinded reviewer. These results were compared with measurements obtained using MRI. The quality of each plain radiograph was evaluated by measuring posterior/distal femoral condylar overlap and length of tibial diaphysis captured on the radiograph. Summary statistics with and without inclusion of measurements made on suboptimal radiographs were calculated.

Of the initial 634 patients with ACLR (317 case-control pairs), 561 (88.5%) had radiographs available and were included for the analysis comparing radiograph to MRI slope measurements. For the evaluation of slope between case and control pairs with radiograph information available, there were 257 case-control pairs; there were 124 pairs when those with suboptimal radiographs were excluded. There was no difference in MRI-measured lateral tibial posterior slope or medial tibial posterior slope for the 257 case-control pairs with XR-PTS information and for the 124 pairs with optimal radiographs. XR-PTS in the revision cohort was significantly steeper than in the control group when suboptimal radiographs were included in the analysis. There was no difference when patients with suboptimal radiographs were excluded. PTS measurements made on plain radiographs were larger than those made on MRI. There was a poor correlation between measurements made using these 2 modalities (r = 0.22 for radiograph and medial PTS).

This study did not find a significantly steeper XR-PTS in patients who had to undergo revision ACLR when suboptimal radiographs were not included in the analysis. The present study's results confirmed the findings from a previous study of the same patient population that used MRI. However, there was poor correlation between PTS measurements made using plain radiograph and MRI.

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.

Anterior cruciate ligament (ACL) injury is a concerning problem in the paediatric population, impacting joint health and longevity. Moreover, ACL injury hampers physical activity, which is important for children's social network and general well-being. Recent data demonstrates a rise in paediatric ACL reconstructions, affecting both girls and boys. However, it is unclear whether this rise reflects a higher injury rate or a more proactive approach towards surgery, as information on nonoperated patients is lacking. Regarding gender differences, increasing evidence implies that girls engaged in pivoting sports experience a higher incidence of ACL injuries and reinjuries compared to boys. Furthermore, data suggest that girls have inferior outcomes and lower return-to-sport rates than boys. The social context in which girls compete in sports is likely a significant contributing factor to the risk of serious knee injuries. Lack of attention and insufficient data on gender-based differences in ACL injuries, outcomes and evidence-based treatment guidelines highlight the need for further research on this topic. LEVEL OF EVIDENCE: Level IV.

Anterior cruciate ligament (ACL) injuries are complex and influenced by numerous internal and external risk factors that should be considered to effectively mitigate injury and facilitate informed return to sport decision-making. Among these risk factors, movement quality exhibited during sport-specific tasks has been identified as a significant predictor of injury occurrence. Particularly, change of direction (COD) movements, when performed with sub-optimal movement quality, such as knee valgus and lateral trunk flexion, are prominent mechanisms of ACL injury in multidirectional sports. Unfortunately, the formal and objective assessment of COD movement quality is underutilized in clinical and sports practice, with existing methods often confined to expensive, sophisticated laboratory settings impractical for everyday clinicians. The purpose of this clinical commentary is to demonstrate the necessity of integrating COD movement assessments to screen for potential ACL injury risk, particularly among higher-risk populations. The authors will review cost-effective and clinic-friendly objective tests used to qualitatively screen COD movements, such as the Cutting Movement Assessment Score and The Expanded Cutting Alignment Tool. Additionally, this commentary will discuss key considerations when assessing COD movement.

5.

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.

To estimate the long term cost savings, return on investment, and gain in quality-adjusted life years (QALYs) that could be achieved by a national anterior cruciate ligament (ACL) injury prevention program for amateur football (soccer) players in Australia.

Markov model decision analysis.

Two hypothetical scenarios including all amateur football players in Australia (340 253 players): no intervention, and a national ACL injury prevention program. Transitions between health states, including ACL rupture, meniscal injury, knee osteoarthritis, and total knee replacement were made in one-year cycles over 35 years from a societal perspective.

Cost savings, return on investment, and QALY gain achieved in the prevention program scenario relative to control scenario, by age group (10-17, 18-34, 35 years or older) and gender.

incidence of ACL rupture, knee osteoarthritis, total knee replacement, and total knee replacement revision.

The total mean cost of an ACL injury was estimated to be $30 665. The national injury prevention program was projected to save $52 539 751 in medical and societal costs caused by ACL ruptures in amateur footballers over 35 years; the estimated return on each dollar invested in the program was $3.51. Over this period, the number of players with ruptured ACLs could be reduced by 4385 (9%), the number of knee osteoarthritis cases by 780 (8.1%), and the number of total knee replacements by 121 (8.1%); 445 QALYs were gained.

Our findings support investing in a national, evidence-based program for the primary prevention of ACL injuries in amateur football players.

Allograft tendons are perceived to have a high ACL graft failure rate in primary anterior cruciate ligament (ACL) reconstruction (ACLR). Historical series may be biased by graft processing methods that degrade the biomechanical properties of donor tendons such as irradiation. Supercritical carbon dioxide (SCCO2) is a validated method of terminally sterilizing biomaterials at physiological temperatures without irradiation, but in vivo use of SCCO2-processed tendon allografts for primary ACLR has not been reported to date.

ACLR with SCCO2 allografts would result in acceptable failure rates, subjective knee scores, and clinical evaluation at 2 years postoperatively.

Case series; Level of evidence, 4.

Patients underwent primary ACLR with terminally sterilized SCCO2-processed human gracilis, peroneus longus, semitendinosus, tibialis anterior, and tibialis posterior tendon allografts. Patient demographics were collected, along with tendon donor age and sex. At 1 year postoperatively, subjective International Knee Documentation Committee (IKDC) and ACL-Return to Sport After Injury (ACL-RSI) scores were collected, as well as clinical evaluation. At 2 years postoperatively, the IKDC and ACL-RSI scores were repeated, and return to sports and further knee injuries were recorded.

A total of 144 patients with a medianage of 26 (IQR 14) years formed the study group. Patients were predominately male (58%). The loss to follow-up rate was 8% (n = 12). The mean age of allograft tendon donors was 37 (range 17-58) years, and the majority were male (83%). The mean allograft diameter was 8.9 ± 1.0 mm. At 2 years, ACL graft failureoccurred in 5% (n = 7). All graft failureswere in patients aged ≤25 years (P = .007). Neither donor age (≤40 or >40 years) nor donor sex was associated with graft failure (P > .05). The median IKDC subjective score was 95 and ACL-RSI score was 75. There were no revisions for sepsis within the first 2 years postoperatively.

SCCO2 processing of allograft tendons demonstrated satisfactory clinical and patient-reported outcomes at 24 months postoperatively in a consecutive series of patients with primary ACLR, with similar ACL graft failure rates and subjective knee scores compared with those reported in published series of hamstring tendon autograft and fresh frozen nonirradiated allograft.

This article aims to assess for clinically important differences in patient-reported outcome measures (PROMs) at one and two years post anterior cruciate ligament reconstruction (ACLR).

A retrospective comparison of prospectively collected PROMs for a single cohort who underwent a primary ACLR with or without associated meniscal surgery from 2016 to 2020 was assessed. Six externally validated PROMs were collected preoperatively and at standardized times postoperatively. Descriptive statistics and paired equivalence testing of PROMs at one and two years after surgery was completed using previously published or calculated minimal clinically important differences as upper and lower equivalence limits. A repeated measures analysis of PROMs that were not clinically equivalent at one and two years after surgery was completed to assess for a clinically significant difference. Subgroup analyses based on sex, age and associated meniscal injury were completed.

One-hundred and forty-five participants with a mean age of 28.7 years (standard deviation: 9.9 years) were included in the final analysis. All PROMs were clinically equivalent at two years compared to one year after ACLR except the quality of life and sport and recreation domains of the Knee Injury and Osteoarthritis Outcome Score (KOOS). The quality of life (mean difference (MD):12.3, P ​< ​0.01, effect size (η2): 0.65) and sport and recreation (MD: 8.78, P ​< ​0.01, η2: 0.50) domains of the KOOS were clinically different at two years compared to one year postoperatively. No major differences were found in the subgroup analyses compared to the entire included sample.

While most PROMs were equivalent at two years compared to one year after ACLR, the quality of life and sport and recreation domains of the KOOS, which reflect knee performance during higher demand activities, exhibited a clinically significant difference.

IV.

To establish the potential link between sex-specific maturation and biomechanical factors associated with ACL injury during dynamic tasks.

Systematic review.

Five databases (CINHAL®, Cochrane Library, PubMed®, Scopus®, and SPORTDiscus) were searched and monitored until 27 May 2024.

Cross-sectional, cohort, case-control, or interventional studies reporting one or more biomechanical variable linked with ACL injury and which assessed participants across two or more maturation phases were considered eligible.

Studies were assessed for risk of bias using a modified version of the Newcastle Ottawa Scale and overall quality of evidence was rated using GRADE. Metrics and effect sizes were presented where available.

Eighteen included studies examined 400 males, 1377 females, and 315 participants of undefined sex across various maturation phases. The methodological quality of most studies (n = 16) was considered good, and satisfactory for two. Knee abduction angle, knee abduction moment, knee flexion angle, and ground reaction forces were most commonly reported. Knee abduction angles and moments and knee flexion angles were greater in late and post-pubertal females than males and pre-pubertal females during both landing and cutting tasks. When normalised for body mass, ground reaction forces were generally greater in males compared to females overall and for less mature participants for both sexes. Overall quality of evidence was low or medium across the four biomechanical measures.

Sex-specific maturation considerations are important in the targeted development and implementation of ACL injury risk identification and prevention strategies.

Graft site morbidities after bone-patellar tendon-bone (BPTB) autograft harvest for anterior cruciate ligament reconstruction (ACLR) negatively impacts rehabilitation. The purpose of this study was to establish tendon structural properties 1-month after BPTB autograft harvest compared to the uninvolved patellar tendon, and subsequently to quantify the healing trajectory of the patellar tendon over the course of rehabilitation. Patellar tendon morphology (ultrasound) and mechanical properties (continuous shear wave elastography) from 3 regions of the tendon (medial, lateral, central) were measured in 34 participants at 1 month, 3-4 months, and 6-9 months after ACLR. Mixed models were used to compare tendon structure between limbs at 1 month, and quantify healing over 3 timepoints. The involved patellar tendon had increased cross-sectional area and thickness in all regions 1-month after ACLR. Thickness reduced uniformly over time. Possible tendon elongation was observed and remained stable over time. Tendon viscosity was uniform across the three regions in the involved limb while the medial region had higher viscosity in the uninvolved limb, and shear modulus was elevated in all three regions at 1 month. Viscosity and shear modulus in only the central region reduced over time. Statement of Clinical Significance: The entire patellar tendon, and not just the central third, is altered after graft harvest. Tendon structure starts to normalize over time, but alterations remain especially in the central third at the time athletes are returning to sport. Early rehabilitation consisting of tendon loading protocols may be necessary to optimize biologic healing at the graft site tendon.

Methodological heterogeneity hinders data comparisons across isolated studies of tendon and ligament properties, limiting clinical understanding and affecting the development and evaluation of replacement materials.

To create an open-access data set on the morphological, biomechanical, and biochemical properties of clinically important tendons and ligaments of the lower limb, using consistent methodologies, to enable direct tendon/ligament comparisons.

Descriptive laboratory study.

Nineteen distinct lower limb tendons and ligaments were retrieved from 8 fresh-frozen human cadavers (5 male, 3 female; aged 49-65 years) including Achilles, tibialis posterior, tibialis anterior, fibularis (peroneus) longus, fibularis (peroneus) brevis, flexor hallucis longus, extensor hallucis longus, plantaris, flexor digitorum longus, quadriceps, patellar, semitendinosus, and gracilis tendons; anterior cruciate, posterior cruciate, medial collateral, and lateral collateral ligaments; and 10 mm-wide grafts from the contralateral quadriceps and patellar tendons. Outcomes included morphology (tissue length, ultrasound-quantified cross-sectional area [CSAUS], and major and minor axes), biomechanics (failure load, ultimate tensile strength [UTS], failure strain, and elastic modulus), and biochemistry (sulfated glycosaminoglycan [sGAG] and hydroxyproline contents). Tissue differences were analyzed using mixed-model regression.

There was a range of similarities and differences between tendons and ligaments across outcomes. A key finding relating to potential graft tissue suitability was the comparable failure loads, UTS, CSAUS, sGAG, and hydroxyproline present between hamstring tendons (a standard graft source) and 5 tendons not typically used for grafting: fibularis (peroneus) longus and brevis, flexor and extensor hallucis longus, and flexor digitorum longus tendons.

This study of lower limb tendons and ligaments has enabled direct comparison of morphological, biomechanical, and biochemical human tissue properties-key factors in the selection of suitable graft tissues. This analysis has identified 6 potential new donor tissues with properties comparable to currently used grafts.

This extensive data set reduces the need to utilize data from incompatible sources, which may aid surgical decisions (eg, evidence to expand the range of tendons considered suitable for use as grafts) and may provide congruent design inputs for new biomaterials and computational models. The complete data set has been provided to facilitate further investigations, with the capacity to expand the resource to include additional outcomes and tissues.

Rehabilitation after an anterior cruciate ligament (ACL) reconstruction requires patience, devotion, and discipline. Rehabilitation should be individualized to each patient's specific need and sport. Return to sport is a continuum throughout the rehabilitation, and patients should not return to performance before passing a battery of muscle function tests and patient-reported outcomes, as well as change of direction-specific tests. Return to full participation should be an agreement between the patient, physical therapist, surgeon, and coach. For minimal risk for second ACL injury, patients should continue with maintenance and prevention training even after returning to sport.

Anterior cruciate ligament reconstruction (ACLR) is a common orthopedic surgery procedure whose incidence has increased over the past few decades. Nevertheless, it is believed that neuromuscular control remains altered from the early stages after ACLR to later years. Therefore, the aim of this study was to systematically evaluate the magnitude of co-contraction during functional tasks in subjects with unilateral ACLR.

A systematic review design was followed. The search strategy was conducted in PubMed, Scopus, EBSCO, PEDro, Cochrane Library, and Web of Science databases from inception to March 2024. The inclusion criteria involved studies using electromyography (EMG) data to calculate muscle pair activation via the co-contraction index (CCI) in ACLR individuals during functional tasks. The Preferred Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed, and study quality was evaluated using National Institutes of Health (NIH) Study Quality Assessment Tools.

The search strategy found a total of 792 studies, of which 15 were included in this systematic review after reviewing the eligibility criteria. The magnitude of co-contraction was assessed in a total of 433 ACLR individuals and 206 controls during functional tasks such as hop, drop-land, step-up/step-down, and gait. Overall, approximately 79.6% of individuals who had undergone ACLR exhibited increased levels of co-contraction magnitude in the ACLR limb, while 8.5% showed low co-contraction levels.

The findings of the review suggest that, during functional tasks, most individuals who have undergone ACLR exhibit changes of co-contraction magnitude in the involved limb.

Paediatric patients demonstrate high re-rupture rates after anterior cruciate ligament reconstruction (ACLR), with numerous surgical techniques proposed to deal with this challenging cohort. This study investigated the early clinical outcomes, complications, return to sport (RTS) and re-rupture rates up until 2-years post-surgery in paediatric patients presenting with open growth plates undergoing transphyseal ACLR that was combined with an extra-articular tenodesis (LET).

Between October 2017 and September 2020, 20 skeletally immature patients were consecutively recruited and underwent transphyseal ACLR and LET. Patient reported outcome measures (PROMs), KT-1000 laxity, knee range of motion (ROM), maximal isokinetic knee torque and a 3-hop battery were assessed at 6-, 12- and 24-months. Limb Symmetry Indices (LSIs), RTS rates, complications, re-ruptures and re-operations were reviewed.

All PROMs improved (p < 0.05). No change (p = 0.903) in laxity between limbs was seen, while 18 patients (90%) demonstrated normal (<3 mm) or near normal (3-5 mm) laxity differences. Peak knee flexion ROM improved over time (p = 0.028), while LSIs for knee extensor strength (p < 0.001), the single (p = 0.002) and triple crossover (p = 0.038) hop tests improved. At 24 months, 18 patients (90%) were participating in their pre-injury pivoting sport activities. No complications, growth disturbances, re-injuries or subsequent surgeries were observed.

Transphyseal ACLR combined with LET, undertaken in skeletally immature paediatric patients, demonstrated high scoring PROMs, physical performance and RTS overall, without evidence of growth disturbance or excessive graft laxity. No re-injuries have been observed at this time with ongoing review required in this high-risk cohort.

Return to sport (RTS) is considered an indicator of successful recovery after anterior cruciate ligament reconstruction (ACLR). In recent years, there has been major interest in documenting RTS following anterior cruciate ligament (ACL) injury. Despite women being at increased risk for ACL injuries and a global increase in women's participation in sports, research has not adequately focused on female athletes.

The purpose of this study is to conduct a systematic review and meta-analysis evaluating the RTS rate in female athletes after ACLR. We hypothesize that most of the female athletes can RTS.

A systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Electronic databases (PubMed, Embase, and Epistemonikos) were searched for articles reporting RTS rates and contextual data in female athletes. The following search terms were used: "anterior cruciate ligament reconstruction" OR "ACL reconstruction" AND "female" OR "women" AND "return to sports" OR "return to play" to retrieve all relevant articles published between 2003 and 2023. A quality assessment of the included studies was conducted.

Fifteen articles were included, reporting on 1456 female athletes participating in pivoting sports. The included studies comprised 9 cohorts, 1 case-control study, 2 case series, 2 descriptive epidemiology studies, and 1 observational study. Eight out of fifteen studies focused solely on elite-level athletes. The participants had a mean age of 23.13 years. Soccer was the most prevalent sport among the participants, accounting for 49.7% of all athletes included. All 15 studies reported an RTS rate, yielding a meta-proportion of 69% [95% CI, 58-80%] for RTS. Nine articles reported the average time to RTS, which was 10.8 months [95% CI, 8.7-12.8 months].

This systematic review demonstrates that a majority of female athletes (69 ​%) can RTS participation at an average of 10.8 months, however, the available information is insufficient, and quantitative data and reasons for not returning to play are lacking. Future studies should establish return-to-play criteria in this population and determine reasons for not returning to play.

III.

Objectives: Although acute anterior cruciate ligament reconstruction (ACLR) is often avoided because of postoperative joint stiffness, delayed ACLR can lead to a longer recovery time and can have a negative impact on physical function due to detraining. This study aimed to determine the effects of acute ACLR on postoperative outcomes, including muscle strength, performance, and return to sports. Methods: A total of 110 patients who underwent anatomical ACLR using hamstring autografts were included in this study and were divided into three groups: acute (ACLR performed within 2 weeks after ACL injury), 2-6 weeks (ACLR performed between 2 and 6 weeks after injury), and 6-12 weeks (ACLR performed between 6 and 12 weeks after injury). Several parameters were evaluated, including range of motion, knee joint stability, isokinetic knee strength, performance, and return to sports. Results: No significant differences were found in the range of motion or knee joint stability between the groups. The acute group exhibited significantly greater quadriceps strength at 3 months postoperatively than the other groups (p < 0.05). The single-leg hop test showed that 66.7%, 38.7%, and 33.3% of the patients in the acute, 2-6 weeks, and 6-12 weeks groups, respectively, recovered to an LSI of 90% or greater (p = 0.09, Cramer's V = 0.27). All patients in the acute group were able to return to sports (p = 0.14; Cramer's V = 0.28). Conclusions: Acute ACLR is advantageous for the early recovery of strength and performance without adverse events. Acute ACLR may shorten the time spent away from sports activities.

Sports participation confers many health benefits yet greatly increases injury risk. Long-term health outcomes in former athletes and transition to life after competitive sports are understudied. Ending a sport may pose physical and psychosocial challenges. The purpose was to determine the lived experiences of former competitive athletes and how their sports participation impacted their long-term health and well-being. Former college varsity athletes participated in semistructured interviews focusing on their experiences, including past and current health, the impact of injuries, activity, exercise, diet and transition to life after competitive sport. Thematic analysis was completed using a collaborative, iterative process. Thirty-one (16 female, 15 male) former college athletes aged 51.3±7.4 years were interviewed. Six themes emerged: (1) lifelong athlete identity; (2) structure, support and challenges of the college athlete experience; (3) a big transition to life beyond competitive sport; (4) impact of competitive sport on long-term health; (5) facilitators and barriers to long-term health after sport and (6) transferable life skills. Continuing sports eased the transition for many but often delayed their postathlete void. Challenges included managing pain and prior injury (eg, If I didn't have my knee injury, I would definitely be more active), reducing energy needs and intake (eg, When I was an athlete, I could eat anything; and unfortunately, that's carried into my regular life), lack of accountability, changed identity and lost resources and social support. Participants suggested a programme, toolkit, mentoring or exit course to facilitate the transition. While former athletes benefit from transferrable life skills and often continue sports and exercise, they face unique challenges such as managing pain and prior injury, staying active, reducing energy intake and changing identity. Future research should develop and evaluate a toolkit, programme and other resources to facilitate life after ending competitive sports under 'normal' conditions (eg, retirement) and after a career-ending injury.

Incidence of paediatric anterior cruciate ligament (ACL) rupture has increased substantially over recent decades. Following ACL rupture, ACL reconstruction (ACLR) surgery is typically performed to restore passive knee stability. This surgery involves replacing the failed ACL with a graft, however, surgeons must select from range of surgical parameters (e.g., type, size, insertion, and pre-tension) with no robust evidence guiding these decisions. This study presents a systemmatic computational approach to study effects of surgical parameter variation on kinematics of paediatric knees.

This study used sequentially-linked neuromusculoskeletal (NMSK) finite element (FE) models of three paediatric knees to estimate the: (i) sensitivity of post-operative knee kinematics to four surgical parameters (type, size, insertion, and pre-tension) through multi-input multi-output sensitivity analysis; (ii) influence of motion and loading conditions throughout stance phase of walking gait on sensitivity indices; and (iii) influence of subject-specific anatomy (i.e., knee size) on sensitivivty indices. A previously validated FE model of the intact knee for each subject served as a reference against which ACLR knee kinematics were compared.

Sensitivity analyses revealed significant influences of surgical parameters on ACLR knee kinematics, albeit without discernible trend favouring any one parameter. Graft size and pre-tension were primary drivers of variation in knee translations and rotations, however, their effects fluctuated across stance indicating motion and loading conditions affect system sensitivity to surgical parameters. Importantly, the sensitivity of knee kinematics to surgical parameter varied across subjects, indicating geometry (i.e., knee size) influenced system sensitivity. Notably, alterations in graft parameters yielded substantial effects on kinematics (normalized root-mean-square-error > 10 %) compared to intact knee models, indicating surgical parameters vary post-operative knee kinematics.

Overall, this initial study highlights the importance of surgical parameter selection on post-operative kinematics in the paediatric ACLR knee, and provides evidence of the need for personalized surgical planning to ultimately enhance patient outcomes.

The distal semitendinosus tendon is commonly harvested for anterior cruciate ligament reconstruction, inducing substantial morbidity at the knee. The aim of this study was to probe how morphological changes of the semitendinosus muscle after harvest of its distal tendon for anterior cruciate ligament reconstruction affects knee flexion strength and whether the knee flexor synergists can compensate for the knee flexion weakness. Ten participants 8-18 months after anterior cruciate ligament reconstruction with an ipsilateral distal semitendinosus tendon autograft performed isometric knee flexion strength testing (15°, 45°, 60°, and 90°; 0° = knee extension) positioned prone on an isokinetic dynamometer. Morphological parameters extracted from magnetic resonance images were used to inform a musculoskeletal model. Knee flexion moments estimated by the model were then compared with those measured experimentally at each knee angle position. A statistically significant between-leg difference in experimentally-measured maximal isometric strength was found at 60° and 90°, but not 15° or 45°, of knee flexion. The musculoskeletal model matched the between-leg differences observed in experimental knee flexion moments at 15° and 45° but did not well estimate between-leg differences with a more flexed knee, particularly at 90°. Further, the knee flexor synergists could not physiologically compensate for weakness in deep knee flexion. These results suggest additional factors other than knee flexor muscle morphology play a role in knee flexion weakness following anterior cruciate ligament reconstruction with a distal semitendinosus tendon graft and thus more work at neural and microscopic levels is required for informing treatment and rehabilitation in this demographic.

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.

To develop and user test an evidence-based patient decision aid for children and adolescents who are considering anterior cruciate ligament (ACL) reconstruction.

Mixed-methods study describing the development of a patient decision aid.

A draft decision aid was developed by a multidisciplinary steering group (including various types of health professionals and researchers, and consumers) informed by the best available evidence and existing patient decision aids.

People who ruptured their ACL when they were under 18 years old (ie, adolescents), their parents, and health professionals who manage these patients. Participants were recruited through social media and the network outreach of the steering group.

Semistructured interviews and questionnaires were used to gather feedback on the decision aid. The feedback was used to refine the decision aid and assess acceptability. An iterative cycle of interviews, refining the aid according to feedback and further interviews, was used. Interviews were analysed using reflexive thematic analysis.

We conducted 32 interviews; 16 health professionals (12 physiotherapists, 4 orthopaedic surgeons) and 16 people who ruptured their ACL when they were under 18 years old (7 were adolescents and 9 were adults at the time of the interview). Parents participated in 8 interviews. Most health professionals, patients and parents rated the aid's acceptability as good-to-excellent. Health professionals and patients agreed on most aspects of the decision aid, but some health professionals had differing views on non-surgical management, risk of harms, treatment protocols and evidence on benefits and harms.

Our patient decision aid is an acceptable tool to help children and adolescents choose an appropriate management option following ACL rupture with their parents and health professionals. A clinical trial evaluating the potential benefit of this tool for children and adolescents considering ACL reconstruction is warranted.