Avoiding Overcorrection to Increase Patient Satisfaction After Open Wedge High Tibial Osteotomy

Clinical and Radiological Outcomes of Medial Meniscal Allograft Transplantation Combined With Realignment Surgery

BACKGROUND

The outcomes of medial meniscal allograft transplantation (MMAT) combined with high tibial osteotomy (HTO) compared with isolated MMAT remain unclear.

PURPOSE

To compare the clinical and radiological results of MMAT combined with HTO and isolated MMAT.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

This retrospective study included 42 consecutive patients, who were divided into group M (isolated MMAT; n = 22) and group H (MMAT combined with HTO with a varus angle >3°; n = 20). Group differences in subjective knee scores, isokinetic muscle strength test, and radiological outcomes (Kellgren-Lawrence grade, mechanical axis, graft extrusion, graft status, and articular cartilage loss) were compared.

RESULTS

The mean follow-up period was 29.2 ± 4.9 months and 27.4 ± 5.3 months for groups M and H, respectively. The Lysholm score improved from 55.4 ± 9.5 to 81.3 ± 9.7 and from 52.6 ± 8.9 to 84.2 ± 10.2 in groups M and H, respectively (both P < .001). The International Knee Documentation Committee subjective score improved from 51.4 ± 10.3 to 79.6 ± 9.4 and from 49.3 ± 11.4 to 81.4 ± 8.3 in groups M and H, respectively (both P < .001). Both groups showed no significant differences in subjective knee scores and isokinetic extensor strength at the final follow-up. The rate of preoperative and postoperative high International Cartilage Regeneration & Joint Preservation Society grade (≥3) did not differ between the 2 groups. Group M showed greater coronal graft extrusion than did group H (3.3 ± 0.7 mm vs 2.7 ± 0.8 mm; P = .014); the rate of pathologic graft extrusion (≥3 mm) was not higher in group M (40.9%) than in group H (20%) with the number of patients available (P = .143). Both groups showed no significant difference in the graft status. Graft tears were observed in 2 patients (9%) in group M and 1 patient (5%) in group H (P = .607).

CONCLUSION

Clinical scores significantly improved after isolated MMAT and MMAT combined with HTO compared with preoperative values, and their short-term outcomes were similar. Postoperative graft extrusion was greater in patients who underwent isolated MMAT, implying that active correction of varus alignment during MMAT may help in intra-articular biomechanics.

Knee Joint Line Obliquity With Adaptational Hip and Ankle Joint Orientation After Medial Open Wedge High Tibial Osteotomy

BACKGROUND

Time-dependent postoperative changes in knee joint line obliquity (KJLO) and subsequent adaptational changes in the hip and ankle joints have not been fully proven after medial open wedge high tibial osteotomy (MOWHTO).

PURPOSE

To investigate the serial postoperative changes in KJLO and subsequent adaptational changes in the hip and ankle joints over time after MOWHTO.

STUDY DESIGN

Case series, Level of evidence, 4.

METHODS

A total of 92 patients who underwent MOWHTO between April 2015 and December 2020 were evaluated. Radiographic parameters, including KJLO, ankle joint line obliquity (ALO), hip abduction angle (HAA), joint line convergence angle, weightbearing line ratio, and hip-knee-ankle angle, were analyzed in time sequence (preoperatively and 3, 6, 12, and 24 months postoperatively). Repeated-measures analysis of variance and post hoc analysis were used to demonstrate alterations and the statistical significance of KJLO and other related radiographic parameters over time.

RESULTS

The mean KJLO values were -1.9°, -2.1°, -2.7°, and -3.2° at 3, 6, 12, and 24 months postoperatively, respectively, indicating that there was consistent increase in valgus tilting of KJLO from 6 to 24 months (P < .001 for both 6-12 months and 12-24 months). ALO and HAA showed significant changes from 6 to 12 months (ALO, P < .001; HAA, P = .002), but not between 12 and 24 months (ALO: -3.0°, -2.7°, -1.9°, and -1.6°; HAA: -0.8°, -0.9°, -1.5°, and -1.8° at 3, 6, 12, and 24 months, respectively). The mean joint line convergence angle, weightbearing line ratio, and hip-knee-ankle angle did not change significantly from 3 months to 24 months postoperatively.

CONCLUSION

There was a consistent increase in valgus tilting of the postoperative KJLO from 6 to 24 months after MOWHTO. The adaptive ALO and HAA significantly changed between 6 and 12 months and were maintained until 24 months after MOWHTO. It is necessary to consider the adaptive change when hip or ankle surgery is planned within this period.

No clinical outcome difference between varus phenotypes after medial opening-wedge high tibial osteotomy at 2 years follow-up

PURPOSE

Clinical studies regarding medial open-wedge high tibial osteotomy (MOWHTO) often analyse a large group of mechanical varus knees rather than differentiating for its primary varus-inducing component. This study aims to compare the radiological and clinical outcomes of the most prevalent varus malalignment phenotypes using the coronal plane alignment of the knee (CPAK) classification.

METHODS

MOWHTO cases with minimal 2-year clinical follow-up were retrospectively selected from a knee osteotomy database (2016-2020). Based on the medial proximal tibial angle (MPTA) and lateral distal femoral angle (LDFA), subjects were allocated to the correct CPAK phenotype pre- and postoperatively. Clinical outcomes were the numeric rating scale (NRS), the knee injury and osteoarthritis outcome score (KOOS) and the therapeutic response rate (TRR) at 2-year follow-up. Inter-observer correlation coefficient (ICC) and unpaired student t test were performed for cross-phenotype comparison.

RESULTS

One hundred thirty-five (135) subjects were found eligible (53.0 years old ±9.6 [19-77], 72% male, 53% left-sided). The most prevalent preoperative phenotype was CPAK 1 (n = 70 (52%)) and the postoperative phenotype was CPAK 6 (n = 66 (49%)). All CPAK phenotypes improved significantly relative to baseline but cross-phenotype comparison yielded no significant differences in clinical outcome. The TRR at 2 years was 67% for CPAK 1, 69% for CPAK 2 and 87% for CPAK 4. The TRR for CPAK 6 was 64% compared with 80% for CPAK 9, which was not significantly different.

CONCLUSION

At 2-year follow-up, no clinically significant differences are observed between different CPAK phenotypes. Accurate MOWHTO corrections provide significant clinical improvement even in the femoral-driven varus knee and the constitutional varus knee dominated by intra-articular wear. The clinical indication for MOWHTO performance should not be reduced to the medial arthritic varus knee with underlying tibial varus alone.

LEVEL OF EVIDENCE

Level IV, retrospective comparative study.

Relationship between increased knee joint line obliquity after medial open-wedge high tibial osteotomy and patient-reported outcome measures

INTRODUCTION

This study evaluated the correlation between postoperative knee joint line obliquity after medial open-wedge high tibial osteotomy and patient-reported outcome measures excluding excessively overcorrected knees. This study further identified preoperative radiological factors related to the increased postoperative knee joint line obliquity.

MATERIALS AND METHODS

We retrospectively evaluated patients who underwent medial open-wedge high tibial osteotomy between March 2013 and March 2021. Postoperative excessively overcorrected knees with hip-knee-ankle angle > 7° were excluded. We investigated radiological parameters and patient-reported outcome measures preoperatively and at the last follow-up. The following radiologic parameters were measured: hip-knee-ankle angle, weight-bearing line ratio, mechanical medial proximal tibial angle, mechanical lateral distal femoral angle, lateral distal tibial angle, joint line convergent angle, knee joint line obliquity, ankle joint line obliquity, hip abduction angle, tibial posterior slope, Carton-Deschamps index, and patella tilting angle. Clinical outcomes were evaluated using Japanese knee outcome measures. This assessment criterion is based on the Western Ontario McMaster Universities Arthritis Index and MOS Short Form 36. Multiple regression analysis was performed to evaluate the association between postoperative knee joint line obliquity and patient-reported outcome measures or preoperative radiological factors (P < .05).

RESULTS

A total of 52 knees were included. The mean age at the time of the surgery was 61.6 ± 9.0 years and the mean follow-up period was 30.6 ± 10.1 months. Increased postoperative knee joint line obliquity was associated with lower Japanese knee outcome measures. The preoperative hip-knee-ankle angle was significantly associated with postoperative knee joint line obliquity.

CONCLUSIONS

Increased knee joint line obliquity after medial open-wedge high tibial osteotomy is associated with inferior clinical outcomes. Care should be given to the center of the rotational angulation in around-knee osteotomy to avoid postoperative increased knee joint line obliquity.

LEVEL OF EVIDENCE

Retrospective comparative study, Level III.

Postoperative Decrease in Bone Marrow Lesion Associated With Better Clinical Outcomes Following Medial Open-Wedge High Tibial Osteotomy

PURPOSE

To assess serial changes of preoperative bone marrow lesion (BML) following medial open-wedge high tibial osteotomy (MOWHTO) up to 2 years and evaluate whether postoperative change of BML affected patient-reported outcome measures (PROMs) at 2 years' follow-up. Factors related to the postoperative changes in BML also were evaluated.

METHODS

The current study retrospectively assessed prospectively collected data of consecutive patients between December 2016 and March 2018 who underwent MOWHTO for symptomatic knee osteoarthritis with varus malalignment (≥5°) and a minimum 2-year follow-up. Serial magnetic resonance imaging scans at preoperative and postoperative 3, 6, 18, and 24 months were performed, and the extent of BML was evaluated consecutively using 2 validated methods. Clinically, preoperative and postoperative PROMs and their achievement of minimal clinically important difference values were evaluated. The associations of the extent of BMLs with PROMs at each follow-up period over time were analyzed using a linear mixed model. Furthermore, factors related to the postoperative changes of BML were assessed.

RESULTS

Of 26 patients, 21 (80.8%) had preoperative BML at medial femoral and tibial condyles. The postoperative decrease in BML was noted in 17 (81.0%) and 18 (85.7%) at medial femoral and tibial condyles. The BML decreased at postoperative 3 months and, thereafter, the extent of BML gradually reduced until postoperative 24 months. The proportion of patients achieved minimal clinically important difference was 84.6% for total Western Ontario and McMaster Universities Osteoarthritis Index scores and 80.8%, 76.9%, and 84.6% for KOOS symptom, pain, and activity of daily living subscales. Postoperative decrease in BML was significantly associated with better PROMs over postoperative 24 months. Furthermore, normo-correction (2°-5° valgus) was a significant factor for decreased BML following MOWHTO.

CONCLUSIONS

Preoperative BML gradually decreased with time following MOWHTO, and the postoperative decrease in BML related with better PROMs over postoperative 24 months. Moreover, postoperative valgus alignment was a significant factor relating the postoperative decrease of BML.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Preoperative joint line obliquity, a newly identified factor for overcorrection, can be incorporated into a novel preoperative planning method to optimise alignment in high tibial osteotomy

PURPOSE

The aim of this study was to analyse the factors associated with additional postoperative alignment changes after accurate bony correction by selecting only patients with well-performed bony correction as planned and develop a method of incorporating significant factors into preoperative planning.

METHODS

Among 104 consecutive patients who underwent medial open wedge high tibial osteotomy (MOWHTO) between October 2019 and July 2022, 61 with well-performed bony corrections were retrospectively reviewed. The major criterion for well-performed bony correction was a difference of <1° between the simulated medial proximal tibial angle (MPTA) and the actual postoperative MPTA as measured in three dimensions. Radiographic parameters, such as the joint line convergence angle (JLCA) and joint line obliquity (JLO), were measured preoperatively and postoperatively, utilising standing and supine whole lower extremity anteroposterior, valgus and varus stress radiographs. Multiple linear regression analysis identified the factors affecting alignment changes, and a prediction model was developed. A method for applying this prediction model to preoperative planning was proposed.

RESULTS

Preoperative JLCA on standing (preJLCAstd ), preoperative JLCA on 0° valgus stress radiograph (vgJLCA0 ), and preoperative JLO (preJLO) were significantly correlated with JLCA change (∆JLCA) (p < 0.001, p < 0.001, p = 0.006). The prediction model was estimated as ∆JLCA = 0.493 × (vgJLCA0 ) - 0.727 × (preJLCAstd ) + 0.189 × (preJLO) - 1.587 in. (R = 0.815, modified R2  = 0.646, p < 0.001). The proposed method resulted in a reduced overcorrection rate (p = 0.003) and an improved proportion of acceptable alignments (p = 0.013).

CONCLUSION

PreJLCAstd , vgJLCA0  and preJLO can be used to estimate ∆JLCA. PreJLO was recently identified as a significant factor associated with additional alignment changes. Utilising the proposed preoperative planning and a prediction model with these factors shows promise in calibrating postoperative alignment after MOWHTO.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

An automated optimization pipeline for clinical-grade computer-assisted planning of high tibial osteotomies under consideration of weight-bearing

3D preoperative planning for high tibial osteotomies (HTO) has increasingly replaced 2D planning but is complex, time-consuming and therefore expensive. Several interdependent clinical objectives and constraints have to be considered, which often requires multiple rounds of revisions between surgeons and biomedical engineers. We therefore developed an automated preoperative planning pipeline, which takes imaging data as an input to generate a ready-to-use, patient-specific planning solution. Deep-learning based segmentation and landmark localization was used to enable the fully automated 3D lower limb deformity assessment. A 2D-3D registration algorithm allowed the transformation of the 3D bone models into the weight-bearing state. Finally, an optimization framework was implemented to generate ready-to use preoperative plannings in a fully automated fashion, using a genetic algorithm to solve the multi-objective optimization (MOO) problem based on several clinical requirements and constraints. The entire pipeline was evaluated on a large clinical dataset of 53 patient cases who previously underwent a medial opening-wedge HTO. The pipeline was used to automatically generate preoperative solutions for these patients. Five experts blindly compared the automatically generated solutions to the previously generated manual plannings. The overall mean rating for the algorithm-generated solutions was better than for the manual solutions. In 90% of all comparisons, they were considered to be equally good or better than the manual solution. The combined use of deep learning approaches, registration methods and MOO can reliably produce ready-to-use preoperative solutions that significantly reduce human workload and related health costs.

Additional anteromedial staple fixation prevents changes in the posterior tibial slope in retrotuberosity bi-planar open-wedge high tibial osteotomy

PURPOSE

To compare the changes in posterior tibial slope (PTS) between retrotuberosity biplane open-wedge high tibial osteotomies (RT-OWHTOs) with and without additional anteromedial staple fixation.

METHODS

Seventy-nine and 77 cases of RT-OWHTOs without (Group N) and with (Group S) additional staple fixation, respectively, were retrospectively reviewed. All procedures were performed using a locking spacer plate. Demographics and preoperative knee condition were similar between the groups. Clinically, the Western Ontario and McMaster Universities Arthritis Index and range of motion were evaluated preoperatively and 2 years postoperatively. Radiographically, the mechanical axis (MA), medial proximal tibial angle (MPTA), and PTS were evaluated preoperatively and within 2 years postoperatively. Hinge fractures were investigated using computed tomography at 2 weeks postoperatively. PTS loss was defined as the difference between the corresponding values at 2 weeks and 2 years postoperatively. The incidence of PTS failure (PTS loss ≥  ± 3°) was also investigated.

RESULTS

The clinical results were not significantly different between groups N and S preoperatively and 2 years postoperatively. There were no significant differences in the MA, MPTA, and PTS between the groups preoperatively and 2 weeks postoperatively; changes in these variables did not differ significantly between the groups. The incidence of hinge fractures, all of which were categorized as Takeuchi type 1, did not differ significantly. PTS loss within 2 years postoperatively was significantly greater in group N than in group S (1.0° vs. 0.1°; p < 0.01). The incidence of the PTS failure was 16.5% (13/79) and 2.6% (2/77) in groups N and S, respectively (p < 0.01).

CONCLUSION

Additional anteromedial staple fixation could prevent changes in the PTS in RT-OWHTO. It is a simple method for preventing an increase in the PTS after RT-OWHTO.

LEVEL OF EVIDENCE

III.

Anatomical Study of the Lateral Tibial Spine as a Landmark for Weight Bearing Line Assessment during High Tibial Osteotomy

Background: Accurate pre-operative planning is essential for successful high tibial osteotomy (HTO). The lateral tibial spine is a commonly used anatomical landmark for weight-bearing line assessment. However, studies on the mediolateral (M-L) position of the lateral tibial spine on the tibial plateau and its variability are limited. Purpose: This study aimed to (1) analyze the M-L position of the lateral tibial spine on the tibial plateau and its variability, (2) investigate radiologic parameters that affect the position of the lateral tibial spine, and (3) determine whether the lateral tibial spine can be a useful anatomical landmark for weight-bearing line assessment during HTO. Materials and Methods: Radiological evaluation was performed on 200 participants (64% female, mean age 42.3 ± 13.2 years) who had standing anterior-posterior plain knee radiographs with a patellar facing forward orientation. The distances from the medial border of the tibial plateau to the lateral spine peak (dLSP) and lateral spine inflection point (dLSI) were measured using a picture archiving and communication system. The medial-lateral inter-spine distance (dISP) was also measured. All parameters were presented as percentages of the entire tibial plateau width. The relationships between the parameters were also investigated. Results: The mean value of dLSP was 56.9 ± 2.5 (52.4-64.5)%, which was 5% lower than the Fujisawa point (62%). The mean value of dLSI was 67.9 ± 2.2 (63.4-75.8)%, which was approximately 5% higher than the Fujisawa point. The values of the dLSP and dLSI were variable among patients, and the upper and lower 10% groups showed significantly higher and lower dLSP and dLSI, respectively, than the middle 10% group. The mean value of dISP was 16.5 ± 2.4%, and it was positively correlated with dLSP and dLSI. Conclusions: On average, the dLSP and dLSI were located -5% and +5% laterally from the conventional Fujisawa point, and they may be useful landmarks for correction amount adjustment during HTO. However, it should be noted that correction based on the lateral tibial spine can be affected by anatomical variations, especially in patients with small or large inter-spine distances.

Change in Cartilage Status of Medial Compartment after Open-Wedge High Tibial Osteotomy without Cartilage Regeneration Procedure: Second Look Arthroscopic Assessment

This study investigated the rate of cartilage regeneration after an open-wedge high tibial osteotomy (HTO) without cartilage regeneration by second-look arthroscopy. This study included patients who underwent an open-wedge HTO between July 2014 and March 2019. A total of 65 patients were enrolled. Pre- and postoperative (second-look arthroscopy) hip-knee-ankle (HKA) angle and tibial slope were measured. All patients underwent arthroscopic examination prior to osteotomy. Medial femoral condyle (MFC) and medial tibial plateau (MTP) articular cartilage were evaluated according to the International Cartilage Repair Society (ICRS) grading system. After 26.5 months, second-look arthroscopy was performed with plate removal to identify the cartilage status of the MFC and MTP. The preoperative HKA angle (6.4° ± 2.7°) was well corrected postoperatively (-2.7° ± 2.7°, p < 0.001). In terms of MFC on second-look arthroscopy, 29 patients (44.6%) showed an improved ICRS grade, 31 patients (47.7%) were maintained, and 5 patients (7.7%) showed a worse ICRS grade since the prior operation. In the MTP group, 19 patients (29.2%) improved, 44 patients (67.7%) were maintained, and 2 patients (3.1%) worsened. Approximately 44.6% and 29.2% of patients showed improved cartilage statuses on the MFC and MTP after open-wedge HTO without any cartilage regeneration procedures. Cartilage regenerations in both the MFC and MTP did not influence clinical outcomes.

Does the anteromedial plate position affect proximal screw length and worsen the clinical outcomes in medial opening wedge high tibial osteotomy?

BACKGROUND

During medial opening wedge high tibial osteotomy (MOWHTO), sometimes the plate tends to be positioned anteromedially. The plate position can affect the length of the proximal screw, which significantly affects stability after osteotomy. Therefore, research on the correlation among plate position, screw length, and clinical outcomes is needed.

METHODS

This retrospective review examines 196 knees in 175 patients who underwent MOWHTO from May 2012 to December 2018, for symptomatic medial compartment osteoarthritis with a varus alignment of > 5°. We evaluated the anteroposterior plate position, length of proximal screw, and postoperative computed tomography (CT). We reviewed patients' clinical outcome scores, presence of lateral hinge fracture, neurovascular complications, and infection. The correlation among proximal plate position, proximal screw length, and clinical outcomes was evaluated using Pearson's correlation analysis. A subgroup analysis by screw angle (> 48 ° or < 48 °) was also performed using chi-square test and Student t-test.

RESULTS

The mean proximal plate position was 16.28% (range, 5.17-44.74) of the proximal tibia's anterior-to-posterior distance ratio, and the proximal screw length averaged 63.8 mm (range, 44-80 mm). Proximal posteromedial plate position and proximal screw length were significantly correlated (r2 = 0.667, P < .001), as were screw angle and length (r2 = 0.746, P < .001). Medial plating (< 48°) can use a longer proximal screw; nevertheless, no significant difference occurred in clinical outcomes between the two groups. Also, no differences occurred in complication rate, including hinge fracture.

CONCLUSION

With more medially positioned plating during MOWHTO, we can use longer proximal screws. However, there was no significant difference in clinical outcomes and the incidence of lateral hinge fractures regardless of plate position and screw length.