Significant slope reduction in ACL deficiency can be achieved both by anterior closing-wedge and medial open-wedge high tibial osteotomies: early experiences in 76 cases

Malrotation Strongly Influences Posterior Tibial Slope Measurement on Lateral Radiographs of the Knee

Background

Posterior tibial slope (PTS) is commonly measured on lateral radiographs, but there is an ongoing discussion on which criteria are essential as quality standards.

Purpose/Hypothesis

The purpose of this study was to evaluate the effect of malrotation of the tibia on lateral radiographs for PTS measurement. It was hypothesized that malrotation alters the measured PTS.

Study Design

Descriptive laboratory study.

Methods

An infratuberositary osteotomy was performed on a tibial saw bone model, and 3 conditions-2 with increased PTS-were tested with the same experimental setup (series 1, closed osteotomy; series 2, 5-mm anterior opening; series 3, 10-mm anterior opening). Long lateral radiographs were taken from +12.5° of external tibial rotation (ETR) to -20° of internal tibial rotation (ITR), in steps of 2.5°. PTS was measured with the mechanical axis (MA) and the proximal anatomic axis (PAA). In addition, the distance between the medial and lateral posterior tibial condyles was measured (in mm).

Results

In test series 1, between +12.5° to 0° of ETR and 0° to-20° of ITR, a change in PTS of 2.8°± 1.0 (ETR) and 3.7°±1.3 (ITR) for the MA and 3.7°± 1.4 (ETR) and 4.1°±1.5 (ITR) for the PAA was detected. In test series 2, changes of 1.5°± 0.5 (ETR) and 3.7±1.3 (ITR) for the MA and 1.6°± 0.6 (ETR) and 4.3°±1.4 (ITR) for the PAA were observed; likewise, in test series 3, changes of 1.8°± 0.7 (ETR) and 3.7°±1.3 (ITR) for the MA and 2.2°± 0.9 (ETR) and 4.2°±1.3 (ITR) for the PAA were observed. ETR of +12.5° resulted in a distance of 5 mm, and ITR of -20° resulted in a distance of 10 mm between the posterior tibial condyles in all testing conditions. There was no significant difference among the 3 testing conditions (P > .05). A change of 1 mm in distance was equivalent to 2° (ITR) or 2.5° (ETR) of change in rotational alignment and 0.4° of change in PTS measurement, irrespective of whether MA or PAA was used.

Conclusion

Tibial malrotation strongly influences PTS measurement on lateral radiographs. ETR leads to an underestimation, and ITR to an overestimation, of PTS. Every 1° of change in rotational alignment was equivalent to 0.2° of change in PTS measurement. For a reliable PTS measurement on lateral radiographs, the posterior tibial condyles should be superimposed exactly.

Clinical Relevance

Dependent on PTS values, surgical correction of the PTS can be indicated. For a correct indication, it is of utmost importance to be able to determine the posterior slope exactly. This investigation demonstrates the effect of tibial rotation on PTS measurement and defines quality criteria, as well as a simple grading system for lateral radiographs for the measurement of the PTS. This helps surgeons to interpret radiographs correctly, allowing a better decision-making process, if and when a corrective osteotomy for PTS correction is indicated.

Combined All-Inside Anterior Cruciate Ligament Reconstruction and Tibial Anterior Closing Wedge Tibial Osteotomy Using Staple Fixation: Surgical Technique

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.

Infratuberositary slope-decreasing anterior closed wedge proximal tibial osteotomy is safe and shows rapid bone healing

PURPOSE

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

STUDY DESIGN

Case series with pooled data of two centres.

LEVEL OF EVIDENCE

Level 4.

Increased posterior tibial slope leads to altered pressure distribution in the lateral tibial plateau-A biomechanical in-vitro study

PURPOSE

The aim of this study is to investigate the impact of increased posterior tibial slope (PTS) on pressure distribution in the medial and lateral tibial plateau. The focus is on compartment-specific effects and potential correlations with cartilage damage, due to altered anterior tibial translation caused by increased PTS.

METHOD

Ten freshly frozen knee specimens were prepared and subjected to biomechanical testing. PTS was modified by inserting 5°, 10°, 15° and 20° polylactic acid wedges into osteotomy gaps. Pressure distribution was measured using Tekscan's Pressure Mapping Sensor 5040™ beneath the menisci at varying PTS angles. The kinetic data were tracked using the Optotrak Certus® system. Statistical analyses were employed to evaluate the pressure shifts and their significance.

RESULTS

The study revealed that increased PTS significantly shifted the pressure point anteriorly on the lateral tibial plateau, while no significant changes were observed on the medial plateau. The analysis of tibial translation showed a corresponding rise in anterior translation with increasing PTS, especially at higher angles.

CONCLUSION

Increased PTS, particularly above 10°, induces significant anterior translation and altered pressure distribution, primarily affecting the lateral tibial plateau. These findings support the hypothesis that elevated PTS contributes to biomechanical stresses in the knee, potentially increasing the risk of lateral compartment cartilage degeneration. These results highlight the importance of considering PTS in clinical assessments and interventions aimed at optimizing knee joint health.

LEVEL OF EVIDENCE

Level IV.

In proximal tibial anterior closing wedge (slope changing) osteotomy lower starting points imply larger bone resection

BACKGROUND

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.

HYPOTHESIS

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

PATIENTS AND METHODS

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.

RESULTS

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).

CONCLUSION

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.

LEVEL OF EVIDENCE

IV; retrospective case-control study.

Clinical outcomes and long-term efficacy of high tibial osteotomy in treating knee instability: An updated systematic review

INTRODUCTION

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

A morphometric study of posterior tibial slope differences by sex and ethnicity in a South African population

PURPOSE

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.

METHOD

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.

RESULTS

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).

CONCLUSION

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 use of four K-wires does not lead to a reduction of the MPTA in the context of a one-dimensional tibial deflection correction of patients with ACL re-rupture and pathologically increased tibial slope

Purpose

Anterior tibial closing wedge osteotomy (ATCWO) has been shown to significantly reduce failure rates of revision anterior cruciate ligament (ACL) reconstructions in patients with a posterior tibial slope (PTS) ≥12°. Recent findings suggest a slight but significant reduction of the medial proximal tibial angle (MPTA) resulting in a varus knee where the sagittal osteotomy plane is based on a total of two guide wires defining the osteotomy wedge without respecting the frontal plane. We hypothesize that the placement of a total of four guide wires intraoperatively can reduce the influence on the MPTA.

Methods

This study retrospectively reports on a two-centre series of 42 ATCWOs for PTS correction between January 2022 and December 2023 at two clinical centres. A total of four guide wires were placed based on a true lateral intraoperative view of the tibia, with two positioned each at the cranial and at the caudal pole of the osteotomy wedge, serving as guides for the saw to create the osteotomy, with careful attention to ensuring that the proximal and distal K-Wires were placed parallel to each other. A retrospective analysis was conducted by examining true lateral and anteroposterior radiographs to identify changes in sagittal and coronal plane alignment.

Results

The study included 19 women and 23 men, with a mean age of 29.7 ± 8.6 years with first-time ACL revision surgery and a minimum PTS of ≥12°. PTS decreased significantly from 14.5 ± 2.8° preoperatively to 8.2 ± 1.9° post-operatively (p < 0.001). The aMPTA demonstrated no significant difference between preoperative (mean aMPTA: 86.9 ± 2.1°) and post-operative (mean aMPTA: 86.6 ± 1.9°) measurements (p > 0.05).

Conclusion

With our technique of placing four guide wires to achieve precise guidance during the insertion of the osteotomy wedge, there is no substantial impact on the aMPTA during slope correction.

Level of Evidence

Level IV.

Cut-off value for the posterior tibial slope indicating the risk for retear of the anterior cruciate ligament

PURPOSE

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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 OF EVIDENCE

Level III.

Slope-Reducing Proximal Tibial Osteotomy Improves Outcomes in Anterior Cruciate Ligament Reconstruction Patients With Elevated Posterior Tibial Slope, Especially Revisions and Posterior Tibial Slope ≥12

PURPOSE

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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 OF EVIDENCE

Level IV, systematic review of Level IV studies.

Proximal tibial anatomical axis and anterior tibial cortex-based measurements of posterior tibial slope on lateral radiographs differ least from actual posterior tibial slope-A biomechanical study

Purpose

To compare different measurement techniques of the posterior tibial slope (PTS) on lateral radiographs with the actual in situ PTS and evaluate the effect of tibial malrotation and image section length.

Methods

Actual PTS was measured on eight fresh-frozen tibiae using a portable 6-axis measuring arm with an accuracy of ±0.01°. True lateral radiographs were taken in the neutral position and after applying 10/20/30° internal/external rotation (IR/ER) and 5/10/15° varus/valgus rotation. The PTS was measured radiographically using five different reference axes: anterior tibial cortex (ATC), anatomical tibial axis, proximal tibial anatomical axis (PTAA), posterior tibial cortex (PTC) and fibular shaft axis (FSA).

Results

The ATC and PTAA methods showed the lowest deviation from the actual PTS, while the PTC method showed the highest difference of 5.5 ± 1.5° (medial) and 7.1 ± 1.8° (lateral) among all tested methods (p < .001). The PTAA technique showed a 1.9 ± 1.4° (medial) and 2.9 ± 1.8° (lateral) difference from the actual slope (n.s.). ER caused the PTS to increase 0.7 ± 2.0° (10° ER, n.s.) to 3.4 ± 2.1° (30° ER, p < .05), whereas IR caused the PTS to decrease 1.6 ± 1.3° (n.s) to 4.1 ± 1.7° (p < .05) when comparing to the PTAA method for the neutral position. Varus and valgus rotation showed the highest deviation from the neutral rotation at 15° valgus (3.1 ± 2.1°, n.s.).

Conclusion

Tibial slope measurements have a high degree of variability between different measurement methods, while the ATC and PTAA methods showed the least deviation from the actual PTS measured in this in vitro model. Malrotation resulted in a severe distortion of the PTS values, which may alter preoperative planning and intraoperative results. Therefore, radiographic PTS measurements may be contrasted with more objective, reproducible and reliable measuring methods.

Level of Evidence

There is no level of evidence as this study was an experimental laboratory study.

[Anterior open wedge osteotomy of the distal femur]

OBJECTIVE

To treat instability caused by a genu recurvatum using ventral open wedge osteotomy of the distal femur.

INDICATIONS

Knee instability caused by Genu recurvatum with femoral extension deformity.

CONTRAINDICATIONS

Inadequate blood flow to the lower extremity, soft tissue issues, obesity, osteoporosis.

SURGICAL TECHNIQUE

Through a primary medial approach to the distal femur, a ventral open wedge osteotomy is performed using chisel bunch formation and arthrodesis spreader. For symmetrical expansion, another lateral approach at the distal femur and insertion of another arthrodesis spreader is performed. Osteosynthesis was performed with an angle stable plate from the medial side and with additional stabilization using a 4-hole angle stable plate from the lateral side. The osteotomy gap was filled with a bone graft wedge.

POSTOPERATIVE MANAGEMENT

Partial weight-bearing of 20 kg was allowed for 6 weeks with passive exercise and lymphatic drainage. A hard frame orthosis for immobilization at 0-10-90° was fitted for 6 weeks. Radiographic controls were performed at 6 weeks, 3 months, and 1 year. After the last radiographic control, hardware was removed.

RESULTS

There are no reports in the current literature regarding the effect of a change in the sagittal plane at the distal femur on alignment, stability, and biomechanics of the knee. This case report shows that genu recurvatum with physiological posterior tibial slope can be successfully treated with anterior femoral flexion osteotomy. Hyperextension was completely eliminated at the follow-up examination after hardware removal after 12 months.

Slope Osteotomies in the Setting of Anterior Cruciate Ligament Deficiency

➤ 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.

Infratubercle Anterior Closing Wedge Osteotomy Corrects Sagittal Alignment without Affecting Coronal Alignment or Patellar Height

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.

Around-the-knee osteotomies part 1: definitions, rationale and planning-state of the art

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.

Combined tibial deflexion osteotomy and anterior cruciate ligament reconstruction improves knee function and stability: A systematic review

IMPORTANCE

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.

OBJECTIVE

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.

EVIDENCE REVIEW

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.

FINDINGS

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.

CONCLUSIONS

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.

STUDY DESIGN

Systematic Review; Level of evidence 4.

Influence of variable hinge positioning on coronal and sagittal alignment in uniplanar medial open-wedge high tibial osteotomy

Purpose

There is a high risk of increasing the posterior tibial slope (PTS) during medially opening-wedge high tibial osteotomy (mowHTO). Most recently, the idea of intentional simultaneous coronal and sagittal correction, using uniplanar cutting techniques has emerged. This study aims to examine the influences of variable hinge positioning and osteotomy gap height on the sagittal and coronal plane.

Methods

Twenty uniplanar mowHTOs were performed in standardised (left) solid-foam proximal tibia models. In the different models, hinge position was rotated stepwise by 10°, between 90° (cutting straight medial to lateral) and 0° (cutting straight anterior to posterior) (n = 10). Additionally, gap heights of 5 and 10 mm were produced and analysed. Logistic regression analysis was performed to calculate a predictive regression formula for the relation between gap height, hinge rotation and the changes of medial proximal tibia angle (MPTA), medial and lateral PTS.

Results

Between cutting angles of 90 and 20°, the MPTA was mainly influenced by the gap height (0.95° MPTA per 1 mm gap height), but not by the cutting angle. Between 20 and 0°, the MPTA was decreased by 3.6° per 10° of rotation, but not by the gap height. Between cutting angles of 90 and 10°, the PTS was increased linearly by 0.97° per 10° of rotation and by 0.61° per 1 mm gap height.

Conclusion

In mowHTO with lateral hinge positions, the MPTA is mainly influenced by gap height. Changes of PTS can be avoided by a straight lateral hinge position. In posterior hinge locations (0-20°), changes of MPTA are mainly caused by hinge rotation, but not by gap height.

Level of Evidence

Level III, Case-control study.

The Role of Osteotomy in Anterior Cruciate Ligament Reconstruction

Coronal and sagittal plane knee malalignments have been shown to increase the forces on anterior cruciate ligament (ACL) grafts after ACL reconstruction (ACLR). Studies have shown the benefit of high tibial osteotomy to address coronal and sagittal imbalance in revision ACLR. The purpose of this article is to further describe the use of osteotomy by reviewing preoperative planning, indications, techniques, and outcomes of high tibial opening and closing wedge as well as anterior tibial closing wedge osteotomies in the setting of ACLR.

Supratubercle Anterior Closing Wedge Osteotomy: No Changes in Patellar Height and Significant Decreases in Anterior Tibial Translation at 6 Months Postoperatively

BACKGROUND

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.

PURPOSE

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

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

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.

RESULTS

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).

CONCLUSION

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.

A Supratuberosity Anterior Closing-Wedge Proximal Tibial Osteotomy Increases Patellar Height: A Simulated Time Zero Uniplanar Radiographic Study

PURPOSE

To simulate the effect of supratuberosity tibial anterior closing-wedge osteotomy (ACWO) in knees with posterior tibial slope (PTS) ≥12° on patellar height when aiming for a target PTS of 5°.

METHODS

The authors retrospectively reviewed true lateral radiographs of the knees of skeletally mature patients scheduled for primary anterior cruciate ligament reconstruction and included all knees with excessive PTS (≥12°). Coordinates of 11 landmarks were digitized to calculate patellar height (Caton-Deschamps index, CDI) and mid-shaft posterior tibial slope (mPTS). The change in patellar height following a simulated supratuberosity ACWO was calculated and compared for knees with patella norma versus alta. A linear univariable regression model predicted the effect of change in mPTS on CDI.

RESULTS

In the final cohort of 83 patients, a simulated supratuberosity ACWO increased CDI from 1.13 (range, 0.73-1.74) to 1.29 (range, 0.84-1.91; P < .001). In 56 patients with patella norma, a simulated supratuberosity ACWO increased CDI from 1.02 (range, 0.73-1.19) to 1.18 (range, 0.84-1.41; P < .001), whereas in patients with patella alta, a simulated supratuberosity ACWO increased CDI from 1.33 (range, 1.20-1.74) to 1.52 (range, 1.36-1.91; P < .001). The linear regression model revealed that a 1° decrease in mPTS increased CDI by 0.02.

CONCLUSIONS

Simulation of a supratuberosity ACWO revealed that the procedure increases patellar height in all knees but did not induce significant differences in patellar height characteristics between knees with patella norma versus alta. A linear regression model revealed that a 1° decrease in mPTS could theoretically increase CDI by 0.02.

CLINICAL RELEVANCE

If preoperative planning indicates that supratuberosity ACWO would increase patellar height from norma (CDI <1.2) to alta (CDI ≥1.2), the surgeon could consider a trans- or infra-tuberosity ACWO, which is less likely to increase patellar height.

Decreased posterior tibial slope is a risk factor for primary posterior cruciate ligament rupture and posterior cruciate ligament reconstruction failure: A systematic review

PURPOSE

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

METHODS

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.

RESULTS

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.

CONCLUSION

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 OF EVIDENCE

Level III.

Menta S, Ranawat AS. Systematic Review of Clinical Outcomes After Proximal Tibia Anterior Closing-Wedge Osteotomy With ACL Reconstruction

Background

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.

Purpose

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

Study Design

Systematic review; Level of evidence, 4.

Methods

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.

Results

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.

Conclusion

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.

Do age, gender, and region affect tibial slope? A multi-center study

INTRODUCTION

Tibial slope is a parameter that is important to recognize in knee kinematics and knee surgery. A very wide range of values governing posterior tibial slope exist in the literature. This study is based on the hypothesis that age, gender and region may have an effect on the tibial slope.

MATERIALS AND METHODS

A total of 1800 lateral knee radiographies from five different countries [Turkey, Germany, Italy, Spain, and the United Kingdom (UK)] were utilized to measure the native posterior tibial slope. Participants were categorized in deciles with each decade of age after 40 years determined as a separate age group. Accordingly, four different age categories were formed in total, namely, the 40- to 49-, 50- to 59-, 60-69, and 70- to 79-year-old groups. Patients with severe knee osteoarthritis, those with a history of arthroscopic and open surgery around the knee, and those with severe morbid obesity and those outside the specified age group were excluded from the study. The angle between the line tangential to the medial tibial plateau and the proximal anatomical axis of the tibia was measured.

RESULTS

The tibial slope values of both males and females in the Turkish population were found to be higher than those in other populations. It was observed that tibial slope values increased with age in females in all populations, except for those in the Spanish and UK populations. In the male population, it was found that tibial slope values increased with age in all populations except in the Spanish population.

CONCLUSIONS

Region, age, and gender affect tibial slope in different populations in various ways. Our study shows that the region an individual lives in and living conditions affect the tibial slope.

Management of anterior cruciate ligament revision in adults: the 2022 ESSKA consensus: part II-surgical strategy

PURPOSE

The aim of this ESSKA consensus is to give recommendations based on scientific evidence and expert opinion to improve the diagnosis, preoperative planning, indication and surgical strategy in Anterior Cruciate Ligament revision.

METHODS

Part 2, presented herein, followed exactly the same methodology as Part 1: the so-called ESSKA formal consensus derived from the Delphi method. Eighteen questions were ultimately asked. The quality of the answers received the following grades of recommendation: Grade A (high level scientific support), Grade B (scientific presumption), Grade C (low level scientific support) or Grade D (expert opinion). All answers were scored from 1 to 9 by the raters. Once a general consensus had been reached between the steering and rating groups, the question-answer sets were submitted to the peer-review group. A final combined meeting of all the members of the consensus was then held to ratify the document.

RESULTS

The review of the literature revealed a rather low scientific quality of studies examining the surgical strategy in cases of ACL reconstruction failure. Of the 18 questions, only 1 received a Grade A rating; 5, a Grade B rating; and 9, grades of C or D. The three remaining complex questions received further evaluations for each portion of the question and were looked at in more detail for the following grades: B and D; A, C and D; or A, B, C and D. The mean rating of all questions by the rating group was 8.0 + - 1.1. The questions and recommendations are listed in the article.

CONCLUSION

ACL revision surgery, especially the surgical strategy, is a widely debated subject with many different opinions and techniques. The literature reveals a poor level of standardization. Therefore, this international European consensus project is of great importance and clinical relevance for guiding the management of ACL revision in adults.

LEVEL OF EVIDENCE

Level II.

Outcomes of Slope-Reducing Proximal Tibial Osteotomy Combined With a Third Anterior Cruciate Ligament Reconstruction Procedure With a Focus on Return to Impact Sports

BACKGROUND

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).

PURPOSE/HYPOTHESIS

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.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Return to Sport Following ACL Reconstruction With Slope-Correcting High Tibial Osteotomy in the Elite Athlete

Background

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.

Indications

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).

Technique

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.

Results

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.

Discussion/Conclusion

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

Patient Consent Disclosure Statement

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.

Effect of Anterior Tibial Closing Wedge Osteotomy on Coronal Tibial Alignment in Relation to Preoperative Medial Proximal Tibial Angle and Wedge Height

BACKGROUND

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.

PURPOSE

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).

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Sufficient Metaphyseal Bone for Wedge Removal and Fixation Hardware During Supratuberosity Tibial Deflexion Osteotomy in Knees With Excessive Posterior Tibial Slope

BACKGROUND

Tibial deflexion osteotomy (TDO) is sometimes indicated for revision anterior cruciate ligament (ACL) reconstruction in knees with posterior tibial slope (PTS) ≥12° and aims to decrease PTS to around 5°. When planning TDO, measuring the anterior tibial metaphyseal height (aHt) could help ascertain whether the available metaphyseal bone would be sufficient to create the wedge and leave adequate residual bone.

PURPOSE

To (1) determine whether, compared with knees with normal native PTS (<12°), aHt is greater in knees with excessive native PTS (≥12°), and (2) verify if, aiming to decrease PTS to 5°, supratuberosity TDO in knees with excessive native PTS could be performed without tibial tuberosity osteotomy, leaving a minimum of 15 mm of residual bone for fixation staples or plates.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

True lateral radiographs of 350 consecutive patients scheduled for ACL reconstruction were digitized to measure PTS, tibial medial plateau length, tibial anterior and posterior metaphyseal heights and inclinations, and patellar height. Measurements were compared between knees with PTS <12° and those with ≥12°. The wedge height required for supratuberosity TDO was estimated for knees with excessive PTS, aiming for a target PTS of 5°, to determine the proportion of knees that would have residual aHt <15 mm.

RESULTS

A total of 326 knees had adequate true lateral radiographs. The mean PTS was 9.8°± 3.1° (range, 1°-20°) and exceeded 12° in 83 (25%) knees. There were no significant differences between knees with normal versus excessive PTS when comparing aHt (30.7 ± 4.5 mm vs 31.6 ± 4.9 mm; P = .270) and medial tibial plateau length (43.1 ± 5.4 mm vs 43.3 ± 5.6 mm; P = .910). Setting the target mPTS at 5° for supratuberosity TDO, the mean residual aHt was 25.0 ± 4.4 mm, and 7 (8%) knees had a residual aHt <20 mm, of which only 1 (1%) had residual aHt <15 mm. Setting the target mPTS at 0°, the mean residual aHt was 21.3 ± 4.2 mm, and 36 (43%) knees had a residual aHt <20 mm, of which only 4 (5%) had residual aHt <15 mm.

CONCLUSION

aHt was not significantly different between knees with normal versus excessive PTS. Estimation of the wedge height required for supratuberosity TDO to reduce excessive PTS to 5° revealed sufficient metaphyseal bone for wedge removal in all knees. Furthermore, 99% of knees would have sufficient residual bone (aHt, ≥15 mm) to accommodate fixation staples or plates, without the need for tibial tuberosity osteotomy.

Tibial Slope on Conventional Lateral Radiographs in Anterior Cruciate Ligament-Injured and Intact Knees: Mean Value and Outliers

BACKGROUND

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.

PURPOSE

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).

STUDY DESIGN

Cross-sectional study; Level of evidence 3.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

High prevalence of increased posterior tibial slope in ACL revision surgery demands a patient-specific approach

PURPOSE

To determine the prevalence of an "increased posterior tibial slope (PTS)" (PTS ≥ 12°) in a population with one, two or ≥ three anterior cruciate ligament (ACL) graft insufficiencies. Furthermore, to investigate whether the prevalence of an increased PTS and the absolute PTS increases with an increasing number of ACL graft insufficiencies, as well as to determine the survival time of the first ACL graft.

METHODS

Patients diagnosed with an ACL graft insufficiency between January 2021 and March 2022 were included. The PTS was measured using the proximal anatomical tibial axis on long lateral knee radiographs. Patients were divided into 3 groups depending on the number of ACL graft insufficiencies: group A (1 graft insufficiency), group B (2 graft insufficiencies) and group C (≥ 3 graft insufficiencies). The prevalence of increased PTS and absolute PTS between groups was compared alongside the survival of the first ACL graft between patients with or without increased PTS.

RESULTS

Two-hundred and six patients (147 males/59 females) met the inclusion criteria. 73 patients showed an increased PTS [prevalence 35% [95% confidence interval (CI) (29%; 42%)]. 155 patients were found in category A, 42 patients in B and 9 patients in C. The prevalence of increased PTS for group A, B and C was, 32% [95% CI (25%; 40%)], 38% [95% CI (23%; 53%)] and 78% [95% CI (51%; 100%)], respectively. The prevalence of increased PTS and mean PTS did not increase significantly between group A and B. However, both parameters increased significantly between group A and C, and group B and C (p < 0.05). The survival time of the first ACL graft in patients with or without an increased PTS was 3 (interquartile range (IQR) 5) and 6 years (IQR 9), respectively (p < 0.05).

CONCLUSION

There is a 35% prevalence of increased PTS in the studied ACL graft insufficient patient cohort. The survival of the first ACL graft is shorter in patients with an increased PTS. Surgeons should be aware of the high prevalence of increased PTS when consulting patients for revision ACL reconstruction as it is an important risk factor for recurrent instability.

Could anterior closed-wedge high tibial osteotomy be a viable option in patients with high posterior tibial slope who undergo anterior cruciate ligament reconstruction? A systematic review and meta-analysis

PURPOSE

This study aims to examine the clinical and radiological outcomes of patients who underwent ACL reconstruction (ACLR) combined with anterior closed-wedge high tibial osteotomy (ACW-HTO) for posterior tibial slope (PTS) reduction to investigate the efficacy of this procedure in improving anterior knee stability and preventing graft failure in primary and revision ACLR.

METHODS

A literature search was conducted in six databases (PubMed, Embase, Medline, Web of Science, Cochrane, and Scopus). The study was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. The initial screening identified 1246 studies. Each eligible clinical article was screened according to the Oxford Centre for Evidence-Based Medicine 2011 levels of evidence (LoE), excluding clinical studies of LoE V. Quality assessment of the articles was performed using the ROBINS-I methodological evaluation. This systematic review and meta-analysis was registered on the International Prospective Register of Systematic Reviews (PROSPERO). For the outcomes that were possible to perform a meta-analysis, a p < 0.05 was considered statistically significant.

RESULTS

Five clinical studies were included in the final analysis. A total of 110 patients were examined. Pre- and post-operative clinical and objective tests that assess anteroposterior knee stability, PTS, clinical scores, and data on surgical characteristics, complications, return to sports activity, and graft failure after ACLR were investigated. A meta-analysis was conducted using R software, version 4.1.3 (2022, R Core Team), for Lysholm score and PTS outcomes. A statistically significant improvement for both these clinical and radiological outcomes (p < 0.05) after the ACW-HTO surgical procedure was found.

CONCLUSION

ACLR combined with ACW-HTO restores knee stability and function with satisfactory clinical and radiological outcomes in patients with an anterior cruciate ligament injury associated with a high PTS and seems to have a protective effect from further ruptures on the reconstructed ACL.

LEVEL OF EVIDENCE

Level IV.

Anterior Closing-Wedge High Tibial Slope-Correcting Osteotomy Using Patient-Specific Preoperative Planning Software for Failed Anterior Cruciate Ligament Reconstruction

Failure of anterior cruciate ligament reconstruction (ACLR) remains a challenging problem. Recently, the effect of increased posterior tibial slope has been identified as a risk factor for ACLR failure. In cases with increased posterior tibial slope, an anterior closing wedge, slope-correcting high tibial osteotomy can be used as a robust adjunct to revision ACLR. In this Technical Note, we demonstrate our preferred method for isolated sagittal plane correction following multiple failed ACLRs with an anterior closing-wedge high tibial osteotomy technique using 3-dimensional patient-specific instrumentation. Through correction of the angular deformity and restoration of the defined sagittal slope via the use of advanced 3-dimensional patient-specific instrumentation, this technique fosters an accurate, favorable mechanical environment to prevent recurrent instability of the knee joint.

Considerations of the Posterior Tibial Slope in Anterior Cruciate Ligament Reconstruction: a Scoping Review

PURPOSE OF REVIEW

The significance of posterior tibial slope (PTS) in the setting of anterior cruciate ligament (ACL) injury and reconstruction has been increasingly recognized in recent years. The purpose of this article is to review the biomechanical and clinical studies of PTS in conjunction with ACL injuries, providing an evidence-based approach for the evaluation and management of this patient population.

RECENT FINDINGS

Several biomechanical and clinical studies suggest that PTS > 12° may be considered with increased strain on the native ACL fibers (or reconstructed graft) and greater anterior tibial translation, predisposing patients to a recurrent ACL injury. The increased rates of ACL injury and graft failure seen in those with increased PTS have garnered attention to diagnose and surgically address increased PTS in the revision ACL setting; however, the role of a slope-reducing high tibial osteotomy (HTO) in primary ACL reconstruction (ACL-R) has yet to be defined. Various HTO techniques to decrease PTS during revision ACL-R have demonstrated promising outcomes, though conclusions are limited by the multifactorial nature of revision surgery and concomitant procedures performed. Recent evidence suggests that increased PTS is a risk factor for failure following ACL-R, which may be mitigated by a slope-reducing HTO. Further investigation is needed to elucidate abnormal PTS values and to determine appropriate indications for a slope-reducing HTO in primary ACL-R.