Closing-Wedge Posterior Tibial Slope-Reducing Osteotomy in Complex Revision ACL Reconstruction

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.

Posterior Tibial Slope Measurements of the Medial and Lateral Plateaus Vary Widely Between Magnetic Resonance Imaging And Computed Tomography

PURPOSE

This study aims to compare posterior tibial slope (PTS) measurements of the medial tibial plateau (MTP) and lateral tibial plateau (LTP) on magnetic resonance imaging (MRI) versus computed tomography (CT) to determine the agreement of measurement between imaging modalities.

METHODS

Patients aged 15-65 years with concurrent MRI and CT imaging were initially included. Knees with significant arthrosis (Kellgren-Lawrence grade >2), proximal tibia fracture, or artifact obscuring visualization were excluded. Two independent raters measured PTS of the MTP and LTP on paired MRI and CT. Interrater and intrarater reliability were assessed using the intraclass correlation coefficient (ICC). Intermethod agreement was assessed using ICC and Bland-Altman analyses. An acceptable Bland-Altman limit of agreement (LOA) was set at ±2°, requiring 95% of measurement differences between imaging modalities to fall between ±2° for an acceptable level of agreement.

RESULTS

46 knees in 45 patients met final inclusion criteria. Interrater reliability was good for MRI (ICC 0.78-0.83) and moderate-to-good for CT (ICC 0.64-0.80) studies. Intrarater reliability was moderate-to-excellent (ICC 0.64-0.94). Intermethod agreement between MRI and CT was poor at the MTP (ICC 0.34-0.42) and moderate at the LTP (ICC 0.59-0.70). Bland-Altman analysis demonstrated high variability of PTS measurements between MRI and CT: 0.16° (95% LOA -6.10-6.41°) for MTP for Rater 1; 0.22° (95% LOA -5.01-5.45°) for LTP for Rater 1; -0.95° (95% LOA -7.22-5.33°) for MTP for Rater 2; -0.99° (95% LOA -6.48-4.85°) for LTP for Rater 2, with only 47.83 to 60.87% of measurement differences falling within the predetermined acceptable LOA of ±2°.

CONCLUSION

Although the interrater and intrarater reliability was moderate-to-excellent, the degree of agreement between PTS measurements on MRI and CT was highly variable at both medial and lateral plateaus. Although some variability may have been due to the study's limitations, PTS measurements at individual plateaus may not be interchangeable between MRI and CT.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

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.

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.

Around-the-knee osteotomies part II: Surgical indications, techniques and outcomes - State of the art

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.

An Update on Emerging Techniques and Considerations in Revision Anterior Cruciate Ligament Reconstruction

» The rate of primary anterior cruciate ligament reconstruction (ACLR) failure in at-risk populations remains unacceptably high and necessitates thorough evaluation of native alignment and concomitant injuries.» Posterior tibial slope of >12° is a substantial risk factor of ACLR failure and should be corrected through anterior closing wedge osteotomy.» Varus malalignment of >5° exacerbates stress on the ACL graft, increases ACLR failure risks, and should be considered for correction through high tibial osteotomy at the time of revision ACLR.» Injuries to the anterolateral ligamentous complex are prevalent in ACL ruptures, and high-risk patients have shown benefit from anterolateral ligament reconstruction or lateral extra-articular tenodesis in the revision setting.» Addressing posterolateral corner, collateral ligament, and meniscal injuries, during revision ACLR, is vital to mitigate increased graft forces and optimize knee stability and functional outcomes.

Revision Anterior Cruciate Ligament Reconstruction and Associated Procedures

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.

Editorial Commentary: Different Levels for Posterior Tibial Slope Reducing Anterior Closing Wedge Osteotomy to Reduce Anterior Cruciate Ligament Reconstruction Failure Present Different Risks

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.

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.

Association of Posterior Tibial Slope With Outcomes After Multiligamentous Knee Reconstruction for Knee Dislocation Grades 2 to 4

Background

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.

Purpose

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

Study Design

Cohort study; Level of evidence, 3.

Methods

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.

Results

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).

Conclusion

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.

Editorial Commentary: Increased Lateral Femoral Condyle Ratio, Increased Posterior Tibial Slope, and Narrow Notch Width Are all Risk Factors for Anterior Cruciate Ligament Tear, and Anterior Cruciate Ligament Graft Tear

Bony risk factors for anterior cruciate ligament (ACL) injuries have been investigated during past 2 decades. Deep posterior femoral condylar depth, measured by the lateral femoral condyle ratio, influences anterolateral instability and the graft survival following ACL reconstructions. Before planning of revision ACL reconstruction, other bony risk factors, including the posterior tibial slope and intercondylar notch width, should be carefully evaluated to protect the ACL graft.

[Subtuberosity anterior closing wedge osteotomy to correct the increased posterior slope of the tibial plateau]

OBJECTIVE

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

INDICATIONS

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

CONTRAINDICATIONS

Hyperextension of more than 15° (relative).

SURGICAL TECHNIQUE

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.

POSTOPERATIVE MANAGEMENT

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

RESULTS

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.

Anterior Proximal Tibial Screw Hemiepiphysiodesis Decreases Posterior Tibial Slope in Knee Flexion Contracture: A Case Report

CASE

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°.

CONCLUSION

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.

[Influence of the bony alignment on the ligaments of the knee joint]

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.

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.

Simultaneous High Tibial Osteotomy and Anterior Cruciate Ligament Reconstruction in knees with Bony Frontal and/or Sagittal Deformities: Review of the Current Literature

Simultaneous anterior cruciate ligament (ACL) reconstruction (ACLR) and valgus high tibial osteotomy (HTO) alleviates pain in 70% of individuals with ACL deficiency and varus femorotibial osteoarthritis, allows for sustainable stabilization of the knee at the 10-year follow-up and a return to sport (RTS) in 33%-80% of cases, but femorotibial osteoarthritis progression occurs in 39% of cases. The complication rate ranges from 0% to 23.5% (6.5% revision valgus HTO, 17.5% ACL graft failure, 7.7% venous thrombosis). Simultaneous ACLR and HTO leads to satisfactory results in patients with ACL deficiency and varus femorotibial osteoarthritis associated with a high posterior tibial slope (PTS) and appears to have a protective effect on further ruptures in the reconstructed ACL. The younger the patient and the more sporting demands he/she poses, the more we should be inclined to perform a combined intervention (ACLR and valgus HTO).