A steep posterior tibial slope (PTS) and excessive anterior tibial subluxation of the lateral compartment (ASLC) have been considered to be associated with inferior graft outcomes in primary anterior cruciate ligament (ACL) reconstruction (ACLR). Case series studies have demonstrated that combined slope-reducing tibial osteotomy can greatly improve knee functional scores and stability in revision ACLR. However, there is currently no comparative study evaluating the clinical benefits of osteotomy procedures in primary ACLR.

To assess the feasibility of combined slope-reducing tibial osteotomy and primary ACLR in patients with a steep PTS and excessive ASLC and to explore the suitable threshold for osteotomy.

Case series; Level of evidence, 4.

Between 2016 and 2022, of the 108 patients with ACL injuries who had a steep PTS (≥15°) and a follow-up ≥2 years, 30 patients with excessive ASLC (≥6 mm) underwent concomitant slope-reducing tibial osteotomy and ACLR (osteotomy group), and 78 patients underwent isolated ACLR (control group). Propensity score matching at a 1:2 ratio was used to match preoperative variables between the 2 groups. After matching preoperative variables, 25 and 48 patients underwent combined surgery and isolated ACLR, respectively. The primary outcome was ACL graft status (failure and laxity rates). The secondary outcomes were ASLC and anterior tibial subluxation of the medial compartment (ASMC), KT-1000 arthrometer side-to-side difference (SSD), pivot-shift grade, and second-look arthroscopic findings. Stratified analysis was performed with 1° PTS increments to explore the osteotomy threshold.

Both groups were comparable in terms of age, sex, side, body mass index, PTS, graft diameter, time from injury to surgery, ASLC, ASMC, KT-1000 arthrometer SSD, pivot-shift grade, and meniscal injuries (all P > .05). The mean PTS significantly decreased from 18.2° to 6.7° (P < .001) in the osteotomy group. The 2-year rate of ACL graft laxity was 12.0% in the osteotomy group and 35.4% in the control group, with a statistically significant difference (P = .033). There was no significant difference in the 2-year rate of ACL graft failure between the 2 groups (8.0% vs 12.5%, respectively; P = .559). The final follow-up data showed that improvements in ASLC (4.5 vs 6.4 mm, respectively; P = .012) and ASMC (2.8 vs 4.5 mm, respectively; P = .014) were more significant in the osteotomy group compared with the control group. On the second-look arthroscopic examination, the incidence of graft roof impingement in the control group was significantly higher than that in the osteotomy group (22.9% vs 4.0%, respectively; P = .039). No significant differences were observed between the 2 groups in terms of KT-1000 arthrometer SSD and high-grade pivot shift (P > .05). Furthermore, stratified analysis revealed that the combined procedure significantly reduced the ACL graft failure rate and improved the KT-1000 arthrometer SSD in patients with a preoperative PTS ≥16°.

Slope-reducing tibial osteotomy combined with primary ACLR significantly decreased the amount of anterior tibial subluxation, the incidence of graft roof impingement, and the graft laxity rate for patients with a steep PTS (≥15°) and excessive ASLC (≥6 mm). Furthermore, in patients with a PTS ≥16°, the combined procedure improved anterior knee stability and reduced the graft failure rate. Therefore, a PTS ≥16° plus ASLC ≥6 mm may be considered an appropriate indication for combining slope-reducing tibial osteotomy with primary ACLR.

Multiple techniques have been utilized to measure posterior tibial slope (PTS) without consensus on which imaging modality, view, and axis combination is most consistent for risk assessment and preoperative planning in primary and revision anterior cruciate ligament (ACL) surgery. An exclusively proximal-based measurement of PTS has yet to be defined.

The purpose of this study was to establish normal values for novel measurements of sagittal proximal tibial morphology, the lateral supratubercle angle (LSTA) and the lateral supratubercle distance (LSTD), in normative and primary ACL tear cohorts. The secondary aim was to establish cutoff values and determine if these tibial measurement values are predictive of the presence of an ACL tear. It was hypothesized that LSTA will be significantly different between cohorts.

Case-control study; Level of evidence, 3.

The medical records of patients with a knee complaint between August 2016 and June 2024 were retrospectively reviewed, and the patients were placed into either the normative or primary ACL tear cohort. Three independent observers measured LSTA, LSTD, and PTS along both the lateral (L) and medial (M) tibial plateaus on standard lateral knee radiographs. Means were calculated for each measurement and compared between groups. The receiver operating characteristic curve was used to determine the sensitivity and specificity of significant measurements.

Significant differences were found between normative (n = 150) and primary ACL tear (n = 150) groups in LSTA-L (normative: 9.9°± 4.4° vs primary ACL tear: 11.1°± 4.4°; P = .02), LSTA-M (normative: 10.3°± 4.4° vs ACL tear: 11.4°± 4.6°; P = .03), and PTS-M (normative: 9.2°± 3.2° vs primary ACL tear: 10.0°± 3.1°; P = .03).

Mean values and ranges for LSTA and LSTD have been established in normative and primary ACL tear cohorts. LSTA-L, LSTA-M, and PTS-M significantly differed between the cohorts. Future studies with LSTA will evaluate the utilization of these proximal tibial deformity-based measurements in ACL surgery, retear risk assessment, and slope-reducing osteotomy planning.

Sagittal-plane slope-reducing high tibial osteotomy (HTO) can reduce the risk of anterior cruciate ligament (ACL) injury in knees with a high posterior tibial slope. The biomechanical effect of slope-reducing HTO on tibiofemoral kinematics and force carried by the ACL remains less well understood.

Decreased tibial slope will be associated with decreased ACL force, coupled internal tibial rotation (ITR), and anterior tibial translation (ATT) under both compressive and combined compressive and valgus loads.

Descriptive laboratory study.

Computational models of 10 cadaveric knees were created using magnetic resonance imaging- and computed tomography-based 3-dimensional renderings of the bones, articular cartilage, and menisci. Virtual slope-reducing HTO was performed on each tibial geometry in 1° increments, creating tibial slopes spanning -5° to 15°. All knees were flexed to 15°, and loads consisting of (1) axial compression (100 N) and (2) combined axial compression (100 N) and valgus torque (8 N·m) were then applied to each knee at each tibial slope. The outcome measures were ACL force, coupled ITR, and ATT. Relationships between tibial slope and each outcome measure were assessed via linear regression (α = .05), and the effects of 10° slope-reducing HTO, from 15° to 5°, on each outcome measure were reported.

A 10° slope-reducing HTO decreased ACL force by 53% under compression (1.7 N of ACL force per degree decrease in tibial slope; P < .001) and 47% under combined compression and valgus (4.7 N of ACL force per degree decrease in tibial slope; P < .001). Regarding kinematics, a 10° slope-reducing HTO decreased coupled ITR by 64% under combined compression and valgus (0.99° of coupled ITR per degree decrease in tibial slope; P < .001). Finally, a 10° slope-reducing HTO decreased ATT by 54% under compression (0.14 mm of ATT per degree decrease in tibial slope; P < .001).

Slope-reducing HTO decreased ACL force linearly by reducing ATT with compression and also by decreasing coupled ITR with combined compression and valgus.

Slope-reducing HTO decreased ATT and coupled ITR, dampening movements known to load the ACL. These findings may provide a further biomechanical basis for the ability of slope-reducing HTO to decrease the risk of ACL injury.

To (1) summarize indications/inclusion criteria and contraindications/exclusion criteria, operative techniques and details, and rehabilitation timelines for slope-reducing osteotomies with concomitant primary or revision anterior cruciate ligament (ACLR) and (2) summarize the radiographic and clinical outcomes that follow these types of surgeries.

Three databases (MEDLINE, PubMed, and EMBASE) were searched on December 22, 2024, for studies with patients undergoing ACLR with concomitant slope-reducing osteotomy. The authors adhered to Preferred Reporting Items for Systematic Reviews and Meta-Analyses and Revised Assessment of Multiple Systematic Reviews guidelines and the Cochrane Handbook for Systematic Reviews of Interventions.

Six case series (Level IV) comprising 193 patients (27.5% female) with a mean age of 28.5 (range of means, 26.9-29.6) years were included. Four of 6 studies (66.7%) reported an indication for slope-reducing osteotomy, being a posterior tibial slope of 12° in revision or re-revision cases. Typical exclusion criteria for osteotomy reported by 5 studies included hyperextension of 5° to 10° or hypermobility (4 studies) and concomitant osteoarthritis (3 studies). Lysholm, Tegner, and visual analog scale scores all statistically increased postoperatively. Rates of return to sport at any level ranged from 81.3% to 100% and 25% to 100%, respectively. Graft failure rates in all studies ranged from 0% to 13%. Rates of recurvatum postoperatively ranged from 15% to 44%. Rates of hardware irritation/removal ranged from 0% to 46.2%.

The most common indication for slope-reducing osteotomies with concurrent ACLR is in the revision setting in patients with a posterior tibial slope above 12°. Slope-reducing osteotomies with ACLR improve patient-reported outcome measures postoperatively and have low rates of instability and retear rates. Complications with osteotomy include postoperative recurvatum, postoperative hyperextension, and hardware removal.

Level IV, systematic review of Level IV studies.

Rupture of the anterior cruciate ligament (ACL) is a common sports injury. Despite continuous improvements over the years, not all patients return to their preoperative activities after treatment of the ACL. Therefore, individualized treatment approaches based on transplant selection, reconstruction technique and biomechanical factors, such as the tibial slope and rotational instability are crucial. Autogenous transplants have different properties in terms of donor site morbidity, healing behavior and risk of rerupture. The individual needs of the patient should therefore be taken into consideration. In terms of the surgical technique, correct tunnel placement based on anatomical landmarks is essential. In addition, concomitant instabilities and meniscus injuries must be addressed. In the event of a rerupture, an exact analysis of the causes is necessary. Ultimately, the success of the treatment depends to a large extent on precise diagnostics and the treatment of both the ACL rupture and any injured accompanying structures.

An excessive posterior tibial slope (PTS) is a risk factor for anterior cruciate ligament (ACL) rupture or rerupture, and it can be managed by an anterior closing wedge high tibial osteotomy (ACW-HTO). The effect of slope-changing osteotomies on patellar height is poorly described after infratuberosity ACW-HTO.

To assess the effect of ACW-HTO on patellar height using an infratuberosity approach.

Case series; Level of evidence, 4.

Patients who underwent ACW-HTO between January 2019 and March 2024 were assessed for eligibility. Among 98 cases, 94 knees were analyzed with a complete radiographic assessment for the patellar height evaluation. Patellar height was measured on lateral radiographs according to the Caton-Deschamps index (CDI), Insall-Salvati index (ISI), and Blackburne-Peel index (BPI). The change in patellar height was assessed postoperatively, as were the rates of cases with a postoperative difference <0.3, <0.5, or >0.5 points of the respective index. The change in patellar height category (baja, normal, or alta) after correction of the PTS was also evaluated.

In univariate analysis, no significant difference was found between pre- and postoperative radiographs for the patellar height indices (differences for ISI: +0.1 ± 0.1, P = .18; CDI: +0.1 ± 0.1, P = .41; BPI: +0.1 ± 0.2, P = .52). The patellar height variation was +0.5 points in only 1 case for CDI, and it was <0.5 points in all other cases (98.9%). Five cases (5.3%) exhibited a postoperative change in patellar height category when measured by the ISI (3 moved up a category, 2 moved down a category; P = .65). Eight cases (8.5%) changed category according to the CDI (6 moved up a category, 2 moved down a category; P = .14). Twelve cases (12.7%) changed category according to the BPI (7 moved up a category, 5 moved down a category; P = .55).

Infratuberosity ACW-HTO for tibial slope correction did not lead to significant changes in patellar height. However, slight variations in both directions were possible in a small portion of patients.

Failure of anterior cruciate ligament (ACL) reconstruction may be associated with a number of technical, anatomic, and patient-related factors. In particular, increased posterior tibial slope is associated with a greater risk of failure after both primary and revision ACL reconstruction, likely a result of increased load across the ACL graft. Surgical treatment of increased posterior tibial slope most commonly involves an anterior closing-wedge osteotomy of the proximal tibia, which may be performed in a simultaneous or staged fashion with ACL reconstruction. The authors describe a technique for combined, single-stage, all-inside ACL reconstruction and anterior closing-wedge osteotomy using staple fixation. The proposed technique provides adequate fixation of the osteotomy while minimizing hardware interference with the ACL tunnel placement and maximizing proximal femoral bone stock.

Different techniques of slope-decreasing anterior closed-wedge proximal tibial osteotomy (ACW-PTO) have been described. To determine the peri- and post-operative complication rate and obtain data on bone healing in ACW-PTO with an infratuberositary approach.

A total of 170 consecutive ACW-PTO of two sports-orthopaedic centres were retrospectively evaluated (97 and 73, respectively). Routine follow-up was performed after 6 weeks and was available in 166 cases (97.7%). Medical charts and x-rays of these cases were reviewed with regard to technique-specific complications. Lateral x-rays (n = 155) at 6 weeks post-operatively were evaluated with regard to bone healing (completely healed, partially healed or with no or delayed signs of bone healing). A multivariate binary logistic regression was performed to detect factors that influence bone healing.

There was one case with haematoma and superficial wound-healing problems after 5 weeks with progression to a deep wound infection and revision surgery (plate exchange) at 11 weeks after the index surgery. One case with delayed bone healing was treated with plate exchange combined with revision anterior cruciate ligament reconstruction after 4 months. The further course of both cases was uneventful. No other complications were observed. Therefore, the overall complication rate was 1.2% (2 out of 166). Radiologic evaluation at 6 weeks showed complete healing in 104 cases (67.1%), partial healing in 50 cases (32.3%) and delayed healing only in the aforementioned case (0.6%), respectively. All cases of partial healing showed complete healing at 12 weeks. In regression analysis, a completely closed osteotomy (odds ratio [OR] = 3.5, p = 0.003) and compression of the osteotomy (OR = 2.5, p = 0.026) were significantly associated with complete bone healing at 6 weeks.

ACW-PTO using an infratuberositary approach is very safe with regard to complication rate and shows rapid bone healing. The osteotomy should be completely closed and compression should be applied for optimal bone healing.

Case series with pooled data of two centres.

Level 4.

Anterior closing wedge osteotomy (ACWO) for tibial slope correction is a validated procedure in revision anterior cruciate ligament reconstruction (ACLR). This study aims to determine how different starting points of the osteotomy affect the amount of bone resection in ACWO.

We hypothesized that the lower osteotomy starting points in ACWO imply larger bone resection.

A total 52 patients who underwent ACWO using infra-tuberosity technique in our institution were included in this study. Each of patients was simulated using additional two separate methods (based on osteotomy level: supra- and trans-tuberosity) based on lateral calibrated pre-operative X-rays of the whole tibia according to the post-operative correction angle. The resection height of the closing wedge, which corresponded to the base of the osteotomy, was measured and compared among the three groups.

The mean actual pre-operative proximal posterior tibial angle (PPTA) was 75.8 ± 2.0°. Post-operatively, PPTA was 84.0 ± 0.6°, and correction angle was 8.2 ± 2.2°. The mean resection height in the supra-tuberosity group was 7.5 ± 0.2 mm, 8.0 ± 2.1 mm in the trans-tuberosity group, and 9.2 ± 2.1 mm in the infra-tuberosity group. There were significant differences between each approach (p ≦ 0.0001). Resection height was moderate positively correlated with the starting point of osteotomy (r = 0.33, 95%CI: 0.18-0.46, p < 0.0001).

This study suggests that selecting a distal starting point for the osteotomy in ACWO is directly proportional to the observed increase in bone resection, providing valuable insights for pre-operative planning. These findings are clinically relevant and will aid in preoperatively deciding approach in ACWO.

IV; retrospective case-control study.

Knee joint stability is influenced by force distribution and ligament structures. High Tibial Osteotomy (HTO) treats knee deformities and redistributes load, reducing further invasive procedures. High Tibial Osteotomy (HTO) is a well-established procedure for addressing knee instability, particularly in cases involving ligament deficiencies such as ACL and PCL insufficiencies. This systematic review aims to evaluate the clinical outcomes and long-term efficacy of HTO in improving knee stability and function.

A systematic literature search was conducted using Cochrane Central, PubMed, MEDLINE, and ProQuest databases for studies published between 2000 and June 2024. Eligible studies included human subjects with at least six months of follow-up and focused on HTO for knee instability. Exclusion criteria included animal studies, non-knee joint studies, and reviews. Data on patient demographics, follow-up duration, subjective and objective outcomes, and complications were extracted.

Out of 536 studies identified, 11 met the inclusion criteria, encompassing 303 patients. Combining HTO with ACL or PCL reconstruction significantly improved both subjective instability and objective measures, including Lachman and Pivot Shift test grades. Patient satisfaction was high, and functional scores such as Lysholm and Tegner improved markedly. The incidence of complications was low, with minor issues such as infections and delayed union, and no reported graft failures.

HTO, particularly when combined with ligament reconstruction, effectively treats knee instability due to ACL or PCL deficiency. The procedure demonstrates strong mid- to long-term outcomes, high patient satisfaction, and a low rate of complications. It remains a viable option for patients with knee instability.

To quantify the effect of increasing the posterior tibial slope (PTS) on knee kinematics and the resultant medial and lateral meniscal forces.

In this controlled laboratory study, a 6 degrees of freedom (DOF) robotic testing system was used to apply external loading conditions to seven fresh-frozen human cadaveric knees: (1) 200-N axial compressive load, (2) 5-N m internal tibial +10-N m valgus torque and (3) 5-N m external tibial + 10-N m varus torque. Knee kinematics and the resultant medial and lateral meniscal forces were acquired for two PTS states: (1) native PTS and (2) increased PTS. Resultant forces in the medial and lateral meniscus were calculated using the principle of superposition.

In response to 5-N m external tibial + 10-N m varus torque, significantly more internal tibial rotation was observed after increasing PTS at 60° (p = 0.0156) and 90° (p = 0.0156) flexion. Increasing PTS caused significantly more medial tibial translation from 30° to 90° flexion in response to 5-N m internal tibial + 10-N m valgus torque. In response to 5-N m external tibial + 10-N m varus torque, the resultant force in the medial meniscus at 60° flexion decreased significantly after increasing PTS (32.8%, p = 0.016). Resultant forces in the lateral meniscus decreased significantly after increasing PTS at 30° (34.5%; p = 0.016) and 90° (29.7%; p = 0.031) flexion in response to 5-N m internal tibial + 10-N m valgus torque.

Increasing PTS in a native knee with intact cruciate ligaments affected 6 DOF knee kinematics and decreased resultant forces in the medial and lateral meniscus by up to 35% in response to combined rotatory loads. Therefore, increasing PTS during high tibial osteotomy in a knee with intact cruciate ligaments does not increase the force carried by the entire meniscus at time zero.

N/A.

Posterior tibial slope (PTS) influences knee kinetics and kinematics. The purpose of this study was to investigate morphology and variation within a sample of the black and white male and female population.

480 randomly selected lateral knee radiographs were included. The anterior tibial cortex angle (ATC), proximal anatomical tibial axis angle (PTAA) and the posterior tibial cortex angle (PTC) were measured using ImageJ 1.53e software. Between group differences (black male and females, white males and females) were analysed using one-way ANOVA.

Significant differences between the three different angles (p = 0.0001, F = 50.68) but no between group differences for the individual angle measurements (ATC, PTAA, PTC) between ethnicity and sex. For ATC, the angles between groups ranged from 14.20 + 2.81 degrees (Females Black), 14.62 + 3.6 degrees (Male Black), 15.18 + 3.68 degrees (Male White) to 15.54 + 3.21 degrees (Females White). For PTAA, the angles between groups ranged from 10.37 + 2.59 degrees (Females Black), 10.61 + 3.27 degrees (Male Black), 10.68 + 3.27 degrees (Male White) to 10.83 + 3.27 degrees (Females White). For PTC, the angles between groups ranged from 6.07 + 3.13 degrees (Females White), 6.13 + 3.7 degrees (Male White), 6.35 + 2.67 degrees (Females Black) to 6.62 + 3.16 degrees (Male Black).

This study could not establish differences in posterior tibial slope angles between males and females and ethnicity. Significant differences between ATC, PTAA and PTC angles were observed and PTC angles were smaller when compared to PTAA and ATC angles. The ATC angles ranged between 13.18 and 16.57 degrees, the PTAA angles ranged 9.38-11.87 degrees and the PTC angles ranged between 5.03 and 7.62 degrees for all groups.

The significance of the posterior tibial slope (PTS) has increasingly come into focus in anterior cruciate ligament (ACL) reconstruction being a risk factor for ACL graft failure. Nevertheless, inconsistent data on the critical value of the PTS exist. The purpose of this study was to define a cut-off value for the PTS in ACL surgery.

In a retrospective cohort study, 350 revision ACL reconstructions (ACL-RR) with a failed ACL hamstring graft and 350 primary ACL reconstructions (ACL-R) were matched according to age, gender, concomitant injuries and graft characteristics and compared to a healthy control group. Using the proximal anatomic axis, lateral knee radiographs were evaluated for the PTS, interrater reliability was defined, ROC curves, Fischer's exact test and Baptista-Pike method were applied to define specificity and the odds ratio for a critical PTS value.

Radiographic evaluation proved excellent interrater reliability (intraclass correlation coefficient 0.969). Evaluation of the PTS revealed 10.0 ± 2.2 (5-15) degrees in the ACL-RR group, 7.8 ± 1.8 (4.2-13) degrees in the ACL-R group and 6.6 ± 1.9 (3.6-12) degrees in the control group with significant differences between the groups (p < 0.001). A PTS value of 10.1 degrees proved a specificity of 98% for the prediction of an ACL graft failure and indicated an 11-fold risk for a retear of the ACL.

A PTS exceeding 10.1 degrees carries an 11-fold risk for ACL graft failure and, therefore, should be considered in ACL reconstruction. These findings might serve as a cut-off value for the indication of a slope-reducing high tibial osteotomy in ACL surgery.

Level III.

If an increased posterior tibial slope (PTS) and concomitant unicompartmental osteoarthritis are present, a simultaneous sagittal (slope) and coronal correcting high tibial osteotomy has been recommended. However, no study has investigated the accuracy of such combined high tibial slope correction osteotomies.

(1) To report the accuracy of navigated high tibial slope correction osteotomies using patient-specific instruments (PSI) and (2) to analyze the influence of an open wedge osteotomy (OWO) versus a closed wedge osteotomy (CWO) and the hinge axis angle (HAA) on the accuracy of the PTS correction.

Cohort study; Level of evidence, 3.

All PSI PTS-reducing osteotomies performed at 1 institution between 2019 and 2022 were reviewed. Three-dimensional (3D) accuracy was defined as the mean absolute 3D angular difference between the planned and achieved surgical correction (in degrees) in 3D models of computed tomography data. The influence of OWO versus CWO and the HAA on the reported accuracy was analyzed and a cutoff defined using receiver operating characteristic curve analysis.

Eighteen patients who underwent a slope-reducing CWO (n = 9) or OWO (n = 9) were included. The 3D accuracy for PTS was 2.3°± 1.1° (mean ± SD), with CWO being more accurate than OWO (1.4°± 0.9° vs 3.1°± 0.6°; P < .01). Accuracy strongly correlated with the HAA (r = 0.788; P < .01). An HAA >38.9° predicted a PTS error >2° (odds ratio, 1.12 [95% CI, 1.04-1.20; P = .004]; area under the curve, 0.95 [95% CI, 0.89-1.00; P < .001]) corresponding to a coronal/sagittal correction of 0.8:1.

Slope-reducing osteotomy can accurately be achieved using PSI. CWO demonstrated an increased accuracy when compared with OWO, which strongly depended on the HAA. With an aim of combined PTS and coronal correction, CWO should be considered the primary choice for accurate slope reduction with a coronal/sagittal correction cutoff of 0.8:1 (HAA, 38.9°).

To explore the indications, outcomes, and complications related to slope-reducing osteotomies in the setting of anterior cruciate ligament (ACL) tears or graft failure. A secondary aim was to create an algorithm on the basis of the current literature and authors' opinions.

This study was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Studies were included if they reported on outcomes related to slope-reducing osteotomies both for primary ACL tears and revision ACL graft tears. The studies were analyzed to determine the radiographic outcomes, patient-reported outcomes (PROs), physical examination findings, and complications. Statistical analysis could not be performed because of the heterogeneity between studies.

A total of 148 studies were screened for inclusion in this systematic review and after full-text review, a total of 16 studies were included in this systematic review. Fourteen of the studies reported on pre- versus postoperative posterior tibial slope (PTS) and all but one reported significant decrease in PTS. Seven studies reported on pre- versus postoperative PROs, and all studies reported significant improvements in postoperative scores. Anterior tibial translation was measured in 8 studies, and all reported a significant decrease in anterior tibial translation postoperatively. The most common complication was postoperative hyperextension and irritation from hardware. Irritation from hardware was only reported in studies that used plates to fixate the osteotomy.

In conclusion, slope-reducing proximal tibial osteotomies performed concurrently or as a second-stage surgery with an anterior cruciate ligament reconstruction (ACLR) resulted in improved PROs and decreased ACLR failure rates. Slope-reducing proximal tibial osteotomies are an important treatment consideration for those patients with an increased PTS, especially for patients with a failed ACLR and a PTS ≥12°, to reduce the risk of ACLR failure.

Level IV, systematic review of Level IV studies.

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.

➤ Posterior tibial slope (PTS) of ≥12° represents an important risk factor for both anterior cruciate ligament (ACL) injury and ACL reconstruction failure.➤ PTS measurements can significantly differ on the basis of the imaging modality and the measurement technique used. PTS should be measured on strictly lateral radiographs, with a recommended proximal tibial length of 15 cm in the image. The PTS measurement can be made by placing 2 circles to define the proximal tibial axis, 1 just below the tibial tubercle and another 10 cm below it. PTS measurements are underestimated when made on magnetic resonance imaging and computed tomography.➤ Slope-reducing osteotomies can be performed using a (1) supratuberosity, (2) tubercle-reflecting transtuberosity, or (3) infratuberosity method. The correction target remains a topic of debate. Although it is controversial, some authors recommend overcorrecting the tibial slope slightly to a range of 4° to 6°. For instance, if the initial slope is 12°, a correction of 6° to 8° should be performed, given the target tibial slope of 4° to 6°.➤ Clinical outcomes following slope-reducing osteotomies have been favorable. However, potential complications, limited data with regard to the impact of slope-reducing osteotomies on osteoarthritis, and uncertainty with regard to the effects on the patellofemoral joint are notable concerns.➤ Patients with complex deformities may need biplanar osteotomies to comprehensively address the condition.

Background: Excessive posterior tibial slope (PTS) has been associated with a higher risk of graft failure after anterior cruciate ligament reconstruction (ACLR). Although anterior closing wedge osteotomy (ACWO) can reduce the PTS, it may also change the coronal alignment and patellar height. Purpose: To elucidate the radiological outcomes after infratubercle ACWO, specifically to evaluate its influence on perioperative changes in patellar height. Methods: Patients who underwent infratubercle ACWO with combined ACLR with a minimum follow-up of 3 months were included. Surgery was indicated when the PTS was greater than 12°. Radiological evaluation included measurements of the hip-knee-ankle angle (HKA), PTS, femoral patellar height index (FPHI), and Caton-Deschamps index (CDI) preoperatively and 3 months postoperatively. Patellar height was classified as patella baja, normal, or alta based on CDI values. Knee recurvatum was measured preoperatively and at final follow-up. Results: A total of 21 patients with a mean age of 21.6 ± 3.0 years were included. Although HKA did not significantly change, significant corrections were achieved in the PTS from 14.5° ± 1.6° to 5.7° ± 1.0° (p < 0.001). No significant change in FPHI was found (preoperative: 1.33 ± 0.11 vs postoperative: 1.30 ± 0.09). Patellar height categories showed no significant differences pre- and postoperatively, while three patients (14.3%) changed their patellar height category (all moved up one category). Knee recurvatum increased significantly from 4.9° ± 2.9° preoperatively to 7.8° ± 3.1° at the final follow-up (p < 0.001). Conclusions: Precise sagittal correction was achieved after infratubercle ACWO without altering the coronal alignment and patella height. Level of Evidence: IV, Case series.

Knee osteotomies are essential orthopedic procedures with the ability to preserve the joint and correct ligament instabilities. Literature supports the correlation between lower limb malalignment and outcomes after knee ligament reconstruction and cartilage procedures. Concepts such as joint line obliquity, posterior tibial slope angle, and intra-articular deformity correction are integral components of both preoperative planning and postoperative evaluations. The concept of preserving and/or restoring joint line congruence during simultaneous correction of varus or valgus deformity can be achieved through several different approaches. With advancements in osteotomy research and surgical planning technology, the surgical decision-making has increased in complexity. Based upon a patient's specific deformity, decisions need to be made whether to perform a single-level (proximal tibia or distal femur) versus double-level (both proximal tibia and distal femur) osteotomy, and whether to correct deformity in a single plane (coronal or sagittal) or perform a biplanar osteotomy, correcting two of the malalignments in either coronal, sagittal, or axial planes. Osteotomy procedures prioritize safety, reproducibility, precision, and meticulous planning. Equally important is the proactive management of possible complications and the implementation of preventive strategies for complications such as hinge fractures and unintentional changes to alignment in other planes. This review navigates the intricate landscape of lower limb alignment, commencing with foundational definitions and rationale for performing osteotomies, progressing through the planning phase, and addressing the critical aspect of complication prevention, all while looking ahead to anticipate future advancements in this field. However, rotational osteotomies and tibial tubercle osteotomies in isolation or as an adjunct procedure are beyond the scope of this review.

Recent advances in surgical techniques and planning for knee-based osteotomies have led to improvements in addressing lower extremity malalignment. Part 1 of this review presented the biomechanical and clinical rationale of osteotomies, emphasizing the importance of osteotomies for restoring normal knee kinematics. In Part 2 of this review, indications, surgical technique and outcomes of osteotomies to correct coronal, sagittal and axial plane deformities will be examined. Traditional high tibial and distal femoral osteotomies will be discussed in addition to more recent advanced techniques including biplanar corrections and double-level osteotomies, as well as slope-correcting osteotomies. Patient-specific instrumentation and its use in more complex corrections will also be addressed.

Patients with excessive posterior tibial slope (PTS) may have higher risks of anterior cruciate ligament (ACL) reconstruction (ACL-R) failure, and clinical outcomes after revision of ACL-R procedures are typically poor.

This study aimed to perform a systematic review of the literature summarizing the clinical and radiological outcomes of the surgical treatment of ACL insufficiency in the setting of excessive PTS using a tibial deflexion osteotomy combined with ACL-R.

A systematic review of the literature was performed using PubMed, Cochrane Library, and OVID Medline databases from 1990 to present. Inclusion criteria were studies of outcomes of isolated tibial deflexion osteotomies performed with primary or revision ACL-R in the English language. Data extracted included study demographic information, type of tibial deflexion osteotomy and concomitant procedures, radiological outcomes, patient-reported outcome scores, and postoperative complications.

Six studies, with 133 knees were identified. All included studies were retrospective case series, with a weighted mean follow-up of 3.39 years. In 106 of 133 (79.7%) knees, tibial deflexion osteotomy was performed concomitantly with an ACL-R, whereas in 27 of 133 (20.3%) knees, the procedures were staged. 22, 45, and 66 of 133 knees (16.5%, 33.8%, and 49.6%) underwent primary, first revision, and second or greater revision ACL-R, respectively. Three of 133 (2.25%) knees demonstrated recurrent ACL graft failure at the final follow-up. On average, PTS decreased from 15.2° preoperatively to 7.1° postoperatively. The mean International Knee Documentation Committee, Lysholm, and Tegner scores increased from 42.5, 46.4, and 4.2 preoperatively to 71.8, 89.0, and 6.7 postoperatively.

The results of this review suggest that combined ACL-R and tibial deflexion osteotomy may be effective in decreasing PTS and improving knee function and stability.

Systematic Review; Level of evidence 4.

Failure of anterior cruciate ligament reconstruction (ACLR) is a common yet devastating complication due to inferior clinical outcomes associated with revision ACLR. Identifying the cause and associated risk factors for failure is the most important consideration during preoperative planning. Special attention to tunnel quality, concomitant injuries, and modifiable risk factors will help determine the optimal approach and staging for revision ACLR. Additional procedures including lateral extra-articular tenodesis and osteotomy may be considered for at-risk populations. The purpose of this review is to explore causes of ACLR failure, clinical indications and appropriate patient evaluation, and technical considerations when performing revision ACLR.

Because of the increased prevalence of revision anterior cruciate ligament (ACL) reconstruction, there has been a desire to understand the role of posterior tibial slope on increased anterior tibial translation and increased ACL graft forces. One potential concern in supratubercle anterior closing wedge proximal tibial osteotomy (ACW-PTO) for decreasing the posterior tibial slope is the risk of altering the patellar height.

To radiographically assess changes in (1) patellar height, (2) anterior tibial translation, and (3) posterior tibial slope after supratubercle ACW-PTO.

Case series; Level of evidence, 4.

Patients who underwent supratubercle ACW-PTO by a single surgeon between July 2019 and June 2023 were included. Standardized lateral knee weightbearing radiographs to assess patellar height (via the Caton-Deschamps index), anterior tibial translation of the lateral tibial plateau relative to the lateral femoral condyle, and posterior tibial slope were obtained at 4 time points (preoperatively and 1 day, 3 months, and 6 months postoperatively). Paired t test was used to compare differences between preoperative, 1-day, and 3- and 6-month values for patellar height as measured using the Caton-Deschamps index and for posterior tibial slope. Paired t test was also used to compare differences in the preoperative and 6-month postoperative values for anterior tibial translation.

In 20 patients after ACW-PTO, the Caton-Deschamps index demonstrated a significant increase in patellar height on postoperative day 1 (P < .001) but no significant differences at 3 (P = .057) and 6 (P = .176) months postoperatively. Anterior tibial translation on standing lateral knee radiographs was significantly decreased by a mean of 8.9 mm from preoperatively to 6 months postoperatively (P < .001). Posterior tibial slope was significantly decreased by a mean of 11.2° from preoperatively to 6 months postoperatively (P < .001).

Supratubercle ACW-PTO performed for ACL reconstruction failure in the setting of an increased posterior tibial slope did not induce significant changes in patellar height postoperatively. Furthermore, after ACW-PTO, there was a significant decrease in anterior tibial translation and posterior tibial slope.

It has become increasingly recognized that a steep posterior tibial slope is a modifiable risk factor for the failure of an anterior cruciate ligament reconstruction. An anterior closing wedge osteotomy (ACWO) may be performed to flatten the slope, and this osteotomy may be performed above, through, or below the tibial tuberosity. A supra-tuberosity technique may increase the patellar height. However, this increase may be modest, may not affect the clinical outcomes, and is only one risk that I would consider when deciding whether to perform an ACWO above, through, or below the tibial tuberosity. The short proximal fragment of supra-tuberosity ACWO mandates a short anterior cruciate ligament reconstruction tibial tunnel and may compromise fixation of the osteotomy. A trans-tuberosity ACWO usually requires a tibial tuberosity osteotomy, which requires slower postoperative mobilization and risks nonunion or fracture of the tibial tubercle. And, an infra-tuberosity ACWO has lesser healing potential than a more proximal osteotomy.

Patients with isolated anterior cruciate ligament (ACL) reconstruction have demonstrated an increased risk of ACL graft failure and lower patient-reported outcome (PRO) scores when increased posterior tibial slope (PTS) is present. However, there is a paucity of literature evaluating the effect of PTS on outcomes after combined bicruciate multiligamentous knee reconstruction.

To determine whether differences exist for graft failure rates or PRO scores based on PTS after combined bicruciate multiligamentous knee reconstruction.

Cohort study; Level of evidence, 3.

All patients who underwent combined ACL and posterior cruciate ligament (PCL) reconstruction between 2000 and 2020 at our institution were identified. Exclusion criteria were age <18 years, knee dislocation grade 5 injuries, concomitant osteotomy procedures, and <2 years of clinical follow-up. Demographic and outcomes data were collected from our prospectively gathered multiligamentous knee injury database. Lysholm and International Knee Documentation Committee (IKDC) scores were analyzed in relation to PTS. Outcomes were compared for patients with a PTS above and below the mean for the total cohort, PTS >12° versus <12°, positive versus negative Lachman test at follow-up, and positive versus negative posterior drawer test at follow-up.

A total of 98 knees in 98 patients were included in the study, with a mean clinical follow-up of 5.1 years (median, 4.6 years; range, 2-16 years). The mean PTS was 8.7° (range, 0.4°-16.9°). Linear regression analysis showed no significant correlation between PTS and IKDC or Lysholm scores. Patients with a PTS above the mean of 8.7° trended toward lower IKDC (P = .08) and Lysholm (P = .06) scores. Four patients experienced ACL graft failure and 5 patients experienced PCL graft failure. There were no differences in graft failure rates or PRO scores for patients with a PTS >12°. Patients with a positive Lachman test trended toward higher PTS (9.6° vs 8.5°, P = .15).

In this series of bicruciate multiligamentous knee reconstructions at midterm follow-up, no differences in graft failures, complications, reoperations, revisions, or PRO scores based on PTS were identified. Patients with a positive Lachman test were found to have a slightly higher PTS, although this did not reach statistical significance.

Failure rates among primary Anterior Cruciate Ligament Reconstruction (ACLR) range from 3.2% to 11.1%. Recently, there has been increased focus on surgical and anatomic considerations which predispose patients to failure, including excessive posterior tibial slope (PTS), unaddressed high-grade pivot shift, and improper tunnel placement. The purpose of this review was to provide a current summary and analysis of the literature regarding patient-related and technical factors surrounding revision ACLR, rehabilitation considerations, overall outcomes and return to sport (RTS) for patients who undergo revision ACLR. There is a convincingly higher re-tear and revision rate in patients who undergo ACLR with allograft than autograft, especially amongst the young, athletic population. Unrecognized Posterior Cruciate Ligament (PLC) injury is a common cause of ACLR failure and current literature suggests concurrent operative management of high-grade PLC injuries. Given the high rates of revision surgery in young active patients who return to pivoting sports, the authors recommend strong consideration of a combined ACLR + Anterolateral Ligament (ALL) or Lateral extra-articular tenodesis (LET) procedure in this population. Excessive PTS has been identified as an independent risk factor for ACL graft failure. Careful consideration of patient-specific factors such as age and activity level may influence the success of ACL reconstruction. Additional technical considerations including graft choice and fixation method, tunnel position, evaluation of concomitant posterolateral corner and high-grade pivot shift injuries, and the role of excessive posterior tibial slope may play a significant role in preventing failure.

Reduction of increased reclination of the tibial plateau (posterior slope) to improve the anterior stability of the knee joint.

Increased posterior reclination of the tibial plateau greater than 12° in combination with recurrent instability after anterior cruciate ligament (ACL) reconstruction.

Hyperextension of more than 15° (relative).

Anterior skin incision approximately 8-10 cm above the tibial tuberosity. Insertion of two converging guidewires directly below the patellar tendon ending obliquely in the area of the posterior cruciate ligament (PCL) insertion. Control of the wire position with the image intensifier core. Oscillating saw osteotomy. Removal of the wedge and closure of the osteotomy. Osteosynthesis with interfragmentary screw and medial angle-stable plate.

Partial load with 10-20 kg for 2 weeks, then step by step increase in load. Mobility: free.

To date we have operated on 36 patients with recurrent instability after ACL reconstruction (20 men, 16 women, average age 34.4 years) in the manner described in this article. In 25 cases, enlarged bone tunnels were filled with allogeneic bone at the same time. The posterior slope of the tibial plateau could be reduced from an average of 14.5° to 8.8°. In 28 cases another ACL reconstruction was performed after an interval of 4-12 months. The Lysholm score significantly increased from 76.3 points to 89.2 points.

A 13-year-old adolescent boy with hemiplegic cerebral palsy suffering from fixed knee flexion deformity of 10° despite extensive conservative treatment. Owing to a posterior tibial slope (PTS) of 16°, anterior hemiepiphysiodesis was applied to the proximal tibia. The 2 screws were removed after 9 months. Final follow-up at 16 months showed complete knee extension and a PTS of 4°.

The presented technique is a good alternative in knee flexion deformity with an increased PTS and has surprisingly not been described in the literature. This might be worth considering for other pathologies such as pediatric anterior cruciate ligament injury with an increased PTS.

A tibial deflexion osteotomy (TDO) is performed to decrease the sagittal tibial slope to reduce the relative risk of anterior cruciate ligament (ACL) reconstruction (ACLR) graft failure. Given that coronal plane osteotomies can cause consequential changes in the sagittal plane to patellar height and tibial slope, potential changes to coronal plane alignment and patellar height can result after a sagittal plane osteotomy.

To compare preoperative and postoperative coronal plane alignment after TDO, as well as to analyze the effect of the osteotomy on patellar height.

Case series; Level of evidence, 4.

This study was conducted on a consecutive series of patients with primary and revision ACLR with concomitant TDO between 2011 and 2022. Inclusion criteria were 1-stage autograft ACLR combined with supratubercular TDO with pre- and 3 months postoperative radiographs of sufficient quality. Indications for TDO were anterior instability requiring ACL revision surgery and a posterior tibial slope (PTS) >9° or a PTS >14° in the primary ACL surgery patients. Anteroposterior and lateral knee radiographs were reviewed, and the medial proximal tibial angle (MPTA), PTS, Caton-Deschamps index (CDI), and modified Insall-Salvati ratio were measured directly from the radiographs by 2 independent reviewers.

A total of 68 patients were included in this study. Pre- and postoperative radiographs were performed 1 month before and 3 months after surgery, respectively. There was a significant increase in the mean MPTA of 0.95° varus (SD, 2.1°; range, increase of 4.23° valgus to increase of 7.74° varus; P < .01), a decreased PTS of 8.86° (SD, 3.03°; P < .01), and an increased CDI of 0.08 (range, decrease of 0.27 to increase of 0.64) (P < .01; SD, 0.17) in patients undergoing TDO. Insall-Salvati ratio measurements showed no difference. There was good intra- and interobserver reliability, with intraclass correlation coefficients of 0.97 and 0.91 for MPTA, 0.97 and 0.87 for PTS, 0.87 and 0.93 for CDI, and 0.88 and 0.76 the Insall-Salvati ratio.

This study, the largest series on TDO for ACLR, demonstrates that the TDO can be performed safely without large changes to coronal alignment or patellar height. The tibial slope was reduced by a mean of 8.86° (range, 2.3°-11.5°; P < .01). The TDO produces a small statistically significant change to coronal alignment, inducing a mean increased varus of <1° and an increased patellar height of 0.1 CDI. Therefore, TDO can be performed safely without dramatic changes to coronal alignment or patellar height, this study highlights technical aspects to minimize iatrogenic varus.

A posterior tibial slope (PTS) >12° is an independent risk factor for anterior cruciate ligament (ACL) graft rupture, and a high tibial osteotomy (HTO) for slope correction can help avoid it. Management of patellar height is of major concern when performing HTO.

To evaluate the effect of tibial tubercle-sparing anterior closing-wedge osteotomy on patellar height in revision ACL reconstruction (ACLR).

Case series; Level of evidence, 4.

Patients who underwent arthroscopic revision ACLR combined with retro-tibial tubercle anterior closing-wedge HTO (ACW-HTO) between January 1, 2016, and March 31, 2021, were assessed for eligibility. Patellar height was measured on full weightbearing lateral radiographs according to the Insall-Salvati index (ISI) and Caton-Deschamps index (CDI) or frontal radiographs using the femoral patellar height index. The PTS was evaluated using the proximal anatomic axis of the tibia on standard short lateral radiographs. The delta (postoperative - preoperative) and the ratio (preoperative/postoperative) of the 3 patellar height indices and PTS were calculated. Preoperative and postoperative patellar heights were compared using independent t tests for each index. Also investigated was whether patients changed patellar height category (baja, normal, or alta) after slope osteotomy.

Among 475 revision ACLRs, 47 tibial tubercle-sparing ACW-HTOs were retained for analysis. No significant difference in patellar height was found between pre- and postoperative radiographs regardless of the index (preoperative - postoperative) (ISI: 1.0 ± 0.2 - 0.9 ± 0.2, P = .1729; CDI: 1.0 ± 0.2 - 1.0 ± 0.2, P = .4034; femoral patellar height index: 1.5 ± 0.2 - 1.5 ± 0.2; P = .5130). Fifteen patients (31.9%) exhibited a postoperative change in their patellar height category when measured by the ISI (6 moved up a category, 9 moved down one), and 18 patients (38.3%) changed category according to the CDI (10 moved up a category, 8 moved down one). No significant difference was found between pre- and postoperative patellar height among these patients (ISI: P = .2418; CDI: P = .3005).

Changes in patellar height ratio are common after tibial tubercle-sparing ACW-HTO in patients undergoing revision ACLR. The clinical effect of these changes is unknown, and further study is needed to investigate whether they may result in patellofemoral symptoms.

To correlate changes in posterior tibial slope (PTS) with changes to static anterior tibial translation (SATT) with tibial deflexion osteotomy (TDO), in order to define a target postoperative tibial slope based on postoperative SATT.

We reviewed a consecutive series of primary and revision anterior cruciate ligament reconstruction with TDO between 2011 and 2022. PTS and SATT were measured pre- and postoperatively directly from the radiographs by 2 independent reviewers. Regression analysis was performed to investigate the relationship of postoperative SATT with PTS, gender, graft type, and meniscal injury.

A total of 48 patients were included in this study. The mean (SD) decrease in PTS and SATT was 8.85° (3.03°; 12.5° to 3.59°, P < .01), and 7.93 mm (3.68; 5.37 to -2.55 mm, P < .01), respectively. Upon univariate analysis, the only factor influencing ΔSATT was ΔPTS. For each 1° of decreased slope, SATT was reduced by 0.46 mm. The mean (SD) PTS for a negative SATT was 2.81° (2.78°) compared to 5.09° (3.25°) for a SATT of 0 to 5mm (P < .01).

This study reports weightbearing SATT in association with PTS after TDO. The TDO successfully reduced the SATT, with the change in PTS the only significant predictor of postoperative SATT. Based on our results, our previously held target of 2° to 5° PTS overcorrected the SATT. Therefore, considering as a goal 0 to 5 mm of SATT, we suggest a new target of 4° to 6° PTS.

Level IV, retrospective cohort study.

Patient factors (notably high tibial slope and narrow femoral intercondylar notch width) and surgical factors (including meniscus treatment and anterior cruciate ligament [ACL] tunnel position) contribute to ACL reconstruction failure. The number one cause of failure is a misplaced ACL femoral tunnel. Tunnel malposition leads to a higher incidence of postoperative meniscal lesions, inferior clinical outcomes, and higher revision rates.

Static anterior tibial translation (SATT) is radiographically measured to show the amount of tibial translation during the single-leg stance, and thus it is representative of the physiological axial load subjected to the anterior cruciate ligament (ACL) during the stance. Increased SATT has been associated with increased posterior tibial slope (PTS) and is also associated with increased graft failure.

To compare the SATT value in a control population with that in a population with an isolated ACL injury, as well as to compare the effect of tibial slope on SATT between the 2 groups.

Cohort study; Level of evidence, 3.

A consecutive series of patients without ligamentous or meniscal injuries between 2019 and 2022 was reviewed. A matched consecutive cohort of patients with nonacute ACL injuries (surgery between 6 and 12 weeks after injury) without concomitant pathology was reviewed. Preoperative SATT and PTS were measured with a previously validated technique on lateral weightbearing knee radiographs. The SATT value was determined, and regression analysis was performed to investigate the relationship between SATT and PTS.

In total, 101 controls and 115 patients with an ACL injury were included in this study. The mean SATT was 1.31 mm (SD, 2.44 mm) and the mean PTS was 10.61° (SD, 3.28°) in the control cohort. The SATT was larger (mean, 2.27 mm; SD, 3.36 mm) in the ACL-injured cohort despite the tibial slope measurement being less in the ACL-injured cohort (mean, 9.46°; SD, 2.85°; P = .016). Linear regression analysis showed that for every 1° of increase in PTS, there was a 0.34-mm increase in SATT in the control cohort; however, there was a greater increase of 0.5 mm for every 1° of increase in PTS in the ACL-injured cohort. We found no significant differences in SATT when the cohorts were compared by age (P = .26) or sex (P = .10).

The present study reports a reference SATT value of 1.31 mm (SD, 2.44 mm) in a non-ACL-injured cohort, which was lower than in the ACL-injured cohort (mean, 2.27 mm; SD, 3.36 mm). The effect of slope on weightbearing anterior tibial translation was greater in the ACL-injured population than in the control cohort.

In recent years biomechanical and clinical studies have shown that the three-dimensional bony alignment of the lower extremities has a relevant influence on the ligamentous structures of the knee and consequently on the stability of the knee joint. Therefore, in the case of pathological ligamentous damage of the knee joint, a possible malalignment must always be thoroughly evaluated and if necessary, included in the treatment planning. Varus malalignment plays an important role especially with respect to the cruciate ligaments as well as the posterolateral ligamentous structures and has been identified as a significant risk factor for failure after surgical reconstruction of these ligamentous structures. Similar data have also been published for valgus malalignment particularly with respect to its negative influence on the anterior cruciate ligament and the medial capsuloligamentous complex. Alignment deviations in the sagittal plane, especially the inclination of the tibial articular surface (slope), have been extensively investigated in several recent studies. It has been demonstrated that the tibial slope has a relevant influence on the anteroposterior stability of the knee joint and hence on the cruciate ligaments. First clinical studies on the surgical correction of the axis in selected patients showed very promising results with the potential of protecting ligament reconstructions against repeated failure; however, further data especially regarding the importance and the exact indications for an additional alignment correction are necessary.

To determine bony knee morphological factors associated with primary posterior cruciate ligament (PCL) rupture or PCL graft failure after PCL reconstruction.

Three databases, namely MEDLINE, PubMed and EMBASE, were searched on 30th May 2023. The authors adhered to the PRISMA and R-AMSTAR guidelines as well as the Cochrane Handbook for Systematic Reviews of Interventions. Data such as receiver operating characteristic curve parameters, as well as p-values for comparisons of values between patients with PCL pathology and control patients, were recorded.

Nine studies comprising 1054 patients were included. Four studies reported that patients with PCL injury had flatter medial posterior tibial slopes (MTS) than controls, with mean values of 4.3 (range: 3.0-7.0) and 6.5 (range: 5.0-9.2) degrees, respectively. Two studies reported an MTS cutoff value ranging below 3.90-3.93° being a significant risk factor for primary PCL rupture or PCL graft failure. Two studies reported that shallow medial tibial depths were associated with primary PCL rupture, with mean values of 2.1 (range: 2.0-2.2) and 2.6 (range: 2.4-2.7) mm in PCL injury and control groups, respectively. Stenotic intercondylar notches and femoral condylar width were not consistently associated with PCL injuries.

Decreased MTS is associated with primary PCL rupture and graft failure after PCL reconstruction with values below 3.93° being considered as a significant risk factor. Less common risk factors include shallow medial tibial depth, while femoral condylar width and parameters with regards to the intercondylar notch, such as notch width, notch width index and intercondylar notch volume, demonstrated conflicting associations with primary or secondary PCL injuries.

Level III.

Biomechanical studies have shown that an increased medial posterior tibial slope (MPTS) may affect anteroposterior knee laxity and tibial shear forces, ultimately increasing the risk for graft failure after anterior cruciate ligament (ACL) reconstruction. Previous clinical studies have, however, reported inconclusive results.

The purpose of this study was to evaluate the relationship between the MPTS and graft failure as well as functional outcomes after anatomic primary isolated ACL reconstruction using a hamstring tendon autograft. It was hypothesized that an increased MPTS would be associated with a higher ACL graft failure rate. Furthermore, a higher MPTS would negatively correlate with functional outcomes in patients without ACL graft failure.

Case-control study; Level of evidence, 3.

Consecutive patients who underwent isolated primary ACL reconstruction with an anteromedial portal drilling technique between January 2011 and December 2019 were retrospectively reviewed. The MPTS was measured on preoperative lateral knee radiographs. At a minimum of 24 months postoperatively, the ACL graft failure rate and patient-reported outcome measures (PROM; International Knee Documentation Committee subjective knee form, Lysholm score, Tegner Activity Scale, visual analog scale for pain and subjective instability) were evaluated. Differences in the MPTS between patients with and without ACL graft failure as well as the frequency of graft failure between those with an MPTS <12° and those with an MPTS ≥12° were assessed for statistical significance. Binary logistic regression analysis was performed to stratify the risk of graft failure with the following variables: MPTS, age at surgery, and sex. Correlation analysis was performed to evaluate the relationship between the MPTS and PROM in patients without ACL graft failure.

In total, 326 patients were included (median follow-up, 71.0 months [IQR, 49.0-104.0 months]). There was no significant difference in the MPTS between patients with and without graft failure (10.6°± 3.2° vs 11.2°± 2.8°, respectively; P = .264). Additionally, there was no significant difference in the frequency of graft failure between patients with an MPTS <12° and those with an MPTS ≥12° (15.6% vs 16.5%, respectively; P = .835). Binary logistic regression showed that younger age at the time of surgery (odds ratio, 1.069 [95% CI, 1.031-1.109]) was associated with graft failure; sex and MPTS were not associated with graft failure. In patients without ACL graft failure, there was no significant correlation between the MPTS and PROM.

In patients who underwent anatomic primary isolated ACL reconstruction, an increased MPTS was not associated with a higher rate of graft failure or inferior functional outcomes. Younger age was a significant nonmodifiable risk factor for ACL graft failure.

While increased posterior tibial slope (PTS) is an important risk factor for failure after anterior cruciate ligament (ACL) reconstruction, controversy exists regarding indications and outcomes of proximal tibia anterior closing-wedge osteotomy (ACWO) with concomitant ACL reconstruction in patients with ACL tears.

To assess clinical outcomes after combined ACL reconstruction and proximal tibia ACWO.

Systematic review; Level of evidence, 4.

In accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines, we performed a systematic review of the existing literature on ACWO and ACL reconstruction using PubMed (MEDLINE), Cochrane Library, Scopus, and Embase. The search phrases included "anterior closing wedge osteotomy,""anterior closing wedge tibial osteotomy,""anterior closing wedge proximal tibial osteotomy,""anterior cruciate ligament," and "revision anterior cruciate ligament." Non-English publications and single-patient case reports were excluded. Extracted data included study details, patient demographics, patient-reported outcomes (PROs), clinical outcomes, radiographic outcomes, complications, and return-to-sport (RTS) rates.

A total of 6 studies with 110 patients (110 knees) were included. Two-stage ACWO and ACL reconstruction was reported in 2 studies of 78 patients (71%), while a single-stage technique was reported in 4 studies of 32 patients (29%). ACWO was performed in the setting of primary ACL tear in 23 patients (21%) and in recurrent ACL tear in 87 patients (79%). Patients demonstrated postoperative improvements in Lysholm, pivot-shift test, and side-to-side difference in anterior tibial translation. After ACWO, all studies reported mean postoperative PTS of <10° (range, 4.4°-9.2°). Of patients with available RTS data (n = 43), the same-level RTS rate ranged from 65% to 100%. A two-stage procedure reported in 1 study had a lower RTS rate (n = 13 of 20 [65%]) than that of 2 studies with single-stage procedure (n = 4 of 5 [80%] and n = 18 of 18 [100%]). The overall complication rate was 0.9% to 1.3%, and there were no reported ACL retears.

The current evidence, which is constrained by the quantity and quality of studies, showed that ACWO with single- or two-stage ACL reconstruction in patients with ACL insufficiency and increased PTS was associated with significant improvements in PROs and high RTS rates.

An increased posterior tibial slope (PTS) is a proven risk factor for both native anterior cruciate ligament (ACL) and ACL graft insufficiency. Anterior closing wedge high tibial osteotomy (ACW-HTO) for PTS correction is a validated procedure in revision ACL reconstruction (ACLR).

The aim of this study was to evaluate the effect of combined ACW-HTO and at least a second revision ACLR procedure on knee stability, function, and sports performance in a large series of patients. The hypothesis was that patients would return to impact sports after ACW-HTO combined with a second or third revision ACLR procedure.

Case series; Level of evidence, 4.

A total of 64 patients who underwent a second (or more) revision ACLR procedure and ACW-HTO between June 1, 2015, and June 1, 2019, and had a PTS >12° were included. The mean age was 29.60 ± 6.31 years, and the mean preoperative PTS was 13.79°± 1.50°. The cases were analyzed at a mean follow-up of 2.96 ± 0.83 years (range, 2-5 years). At the last follow-up, the rate of patients returning to impact sports (based on the University of California, Los Angeles [UCLA], activity scale), ACL graft status (per magnetic resonance imaging), International Knee Documentation Committee (IKDC) scores, Lysholm scores, and laxity measurements using a knee arthrometer were recorded.

The total number of patients participating in impact sports and high-impact sports was as follows: 43 and 30, respectively, before the injury; 0 and 0, respectively, preoperatively; and 31 and 12, respectively, postoperatively. At the last follow-up, the UCLA score was ≥8 in 48.44% of the patients, and only 16 patients returned to their preinjury level of activity. At a minimum of 2 years of follow-up, there was clinical improvement in the IKDC score from 37.98 ± 12.48 preoperatively to 69.06 ± 12.30 postoperatively (P < .0001), in the Lysholm score from 51.94 ± 14.03 preoperatively to 74.45 ± 11.44 postoperatively (P < .001), and in the UCLA score. However, this clinical improvement did not equate to preinjury values for all outcome scores (P < .001). The preinjury IKDC and Lysholm scores were 76.98 ± 11.71 and 89.26 ± 8.91, respectively. The mean change in anterior knee laxity using a knee arthrometer at 134 and 250 N was -4.03 ± 0.18 mm and -3.63 ± 0.16, respectively. There were 3 cases of a rerupture with a severe pivot shift on the clinical examination. None of these patients underwent revision per the patient's preference. Increased knee recurvatum was observed in one-third of the patients, but all were asymptomatic.

In the setting of chronic ACL-deficient knees, PTS reduction (ACW-HTO) with revision ACLR restored knee stability and improved function with an acceptable rate of specific complications. Increased knee recurvatum was observed in one-third of the patients, but all were asymptomatic. Also, approximately half of the patients were able to return to impact sports.

➤ Joint alignment, meniscal status, and ligament stability are codependent factors involved in knee joint preservation, and any injury or imbalance can impact the knee articular cartilage status and can result in adverse clinical outcomes.➤ Cartilage preservation procedures in the knee will not result in optimal outcomes if there is joint malalignment, meniscal deficiency, or ligamentous instability.➤ Lower-extremity varus or valgus malalignment is a risk factor for the failure of an anterior cruciate ligament (ACL) reconstruction. It represents an indication for a high tibial osteotomy or distal femoral osteotomy in the setting of failed ACL reconstruction, and may even be considered in patients who have an initial ACL injury and severe malalignment.➤ An elevated posterior tibial slope increases the risk of failure of ACL reconstruction, whereas a decreased posterior tibial slope increases the risk of failure of posterior cruciate ligament reconstruction.

Currently, periarticular knee joint osteotomies are an integral part of the treatment of early arthritic deformities in the knee joint.

Analysis of the deformity is performed with a standardized full-leg standing x‑ray of both legs, as well as a lateral x‑ray of the knee joint that includes 2/3 of the proximal tibial shaft. An MRI examination of the knee joint is obtained to assess the articular cartilage, the ligaments and menisci. Torsion angle measurements with the CT/MRT supplement the diagnostics if necessary. Knowledge of normal physiological values and their standard deviations of the mechanical leg axis and the joint angles around the knee is obligatory.

The osteotomy is performed as close as possible to the femoral and/or tibial deformity. Postsurgical deformities including pathological patella position or a significant difference in leg length must be prevented. A description of proximal tibia opening or closing wedge osteotomies based on the nomenclature of the joint angles by Paley is presented. The indications for the various osteotomy techniques in the coronary plane are discussed in detail.

Increased posterior tibial slope is a strong predictor of anterior cruciate ligament (ACL) graft re-injury. A concomitant slope-reducing high tibial osteotomy (HTO) has been suggested to decrease re-tear risk in these cases although little is known regarding outcomes following ACL reconstruction with HTO, especially in elite athletic patients.

A 19-year-old National Collegiate Athletics Association (NCAA) Division 1 running back presented with an ACL tear, lateral meniscus tear, and posterior tibial slope of 19° (case 1). A 19-year-old NCAA Division 1 soccer forward presented with an ACL graft re-tear and posterior tibial slope of 21° (case 2).

Anterior closing wedge HTOs were performed along with a primary ACL reconstruction with quadriceps tendon autograft (case 1) and a revision ACL reconstruction with quadriceps tendon autograft (case 2). Following the arthroscopic procedures, an anterior approach was used to insert the first guide wire distal to the patellar tendon insertion from anterior to posterior aiming toward the posterior curve of the tibia. A second guide wire was placed at the previously templated distance. The osteotomy was then performed utilizing a saw and then osteotome. The reduction was performed by gently lifting the ankle anteriorly and applying axial pressure, and a new posterior tibial slope was calculated. After the osteotomy site was reduced, a preliminary reduction was performed by applying a clamp to both wires followed by placing a wire across the osteotomy site aiming from anterolateral to posteromedial. An anterolateral proximal tibial plate was applied, as well as a lag screw across the osteotomy site.

At 6 months after surgery, case 1 demonstrated >90% Limb Symmetry Indices (LSI) with quadriceps strength, single leg hop tests, and change of direction tests. At 12 months after surgery, case 2 demonstrated >90% LSI with all functional testing and competed in 17 games. Both patients returned to preinjury performance metrics including top speed and vertical jump height. No significant postoperative complications or instability was observed.

Primary or revision ACL reconstruction with HTO shows potential to assist athletes in returning to high-level sport while reducing posterior slope.

The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

The posterior tibial slope has been identified as an anatomic risk factor for anterior cruciate ligament insufficiency and reruptures after anterior cruciate ligament reconstruction. Anterior tibial closing wedge osteotomy for correction of sagittal plane deformities has the potential to cause an unintended change in coronal plane alignment.

To evaluate the effects of anterior tibial closing wedge osteotomies for correction of posterior tibial slope on coronal plane alignment using an infratuberosity surgical approach and to identify predictive factors for a change in medial proximal tibial angle (MPTA).

Case series; Level of evidence, 4.

This study reports on retrospectively obtained data from radiographic measurements of 38 anterior tibial closing wedge osteotomies. All patients underwent revision anterior cruciate ligament reconstruction and had undergone ≥1 previous anterior cruciate ligament reconstruction. In all patients, an infratuberosity approach was used with angular stable plate fixation. Pre- and postoperative radiographs were examined retrospectively to detect changes in the sagittal and coronal plane alignment (posterior tibial slope and MPTA). A multivariate regression analysis was used to identify predictors for a change in MPTA.

The study group consisted of 14 women and 24 men whose mean ± SD age at the index procedure was 31.6 ± 8.7 years (range, 17-51 years). Posterior tibial slope decreased significantly (by 7.2° ± 2.3°; P < .001) from 14.6° ± 2.0° preoperatively to 7.4° ± 2.1° postoperatively. MPTA decreased significantly by 1.3° ± 1.5° (P = .005) from pre- to postoperative measurement. Mean wedge height was 9.3 ± 1.1 mm. A lower preoperative MPTA (coefficient = 0.32; P = .017; 95% CI, 0.06-0.59) and larger wedge height (coefficient = 0.48; P = .029; 95% CI, 0.05-0.9) were significant predictive factors for a decrease in MPTA.

Anterior tibial closing wedge osteotomy for posterior tibial slope reduction resulted in a slight but significant decrease of the MPTA in the coronal plane. These changes were dependent on the preoperative MPTA and the wedge height.

An increased tibial slope (TS) has been identified as a risk factor for anterior cruciate ligament (ACL) injury and graft failure after ACL reconstruction. However, different imaging modalities are used to determine the TS, resulting in divergent values. Consequently, no reference values and no consensus on thresholds can be reached, which in turn is mandatory for indicating correction osteotomies when facing outlier TS.

To determine the mean values of the TS and the incidence of their outliers in large cohorts of patients with ACL-injured and noninjured knees and to determine the feasibility of measuring TS on conventional lateral radiographs (CLRs).

Cross-sectional study; Level of evidence 3.

TS of ACL-injured knees (n = 1000, group A) and ACL-intact knees (n = 1000, group B) was measured by 3 experienced examiners. Medial TS was measured on CLRs using the technique of Dejour and Bonnin. Patients with radiographs with poor image quality, osteoarthritis, previous osteotomies, or nondigital radiographs were excluded. The intra- and interrater reliability was calculated using the intraclass correlation coefficient.

The mean TS was significantly higher in group A than in group B (10.04°± 3° [range, 2°-22°] vs 9.02°± 2.9° [range, 1°-18°], respectively; P < .001). Significantly more participants in group A had TS larger than 12° (≥12°, 32.2% vs 19.8%, P < .001; ≥13°, 20.9% vs 11.1%, P < .001; ≥14°, 13.5% vs 5.7%, P < .001; ≥15°, 8% vs 2.7%, P < .001; ≥16°, 3.7% vs 1.4%, P = .0005), respectively. In contrast, significantly more participatns in group B had TS 8° or less (≤8°, 32.1% vs 42.7%, P < .001; ≤7°, 20% vs 30.9%, P < .001; ≤6°, 12.4% vs 19.8%, P < .001; ≤5°, 6.6% vs 12%, P = .0003; ≤4°, 2.8% vs 5.3%, P = .0045). The intraclass correlation coefficient revealed a good to excellent reliability throughout measurements.

Median values for the TS were 9° for uninjured and 10° for ACL-injured knees on CLRs. Notwithstanding its statistical significance, this finding might be negligible in clinical practice. However, a significantly larger number of outliers were found in the ACL-injured group exceeding a TS of 12° and demonstrating an incremental proportion with increasing TS, serving as a potential threshold for correction osteotomy. Furthermore, CLRs in the largest cohort to date exhibited high reproducibility, proving the feasibility of CLRs as a routine measurement for TS.