Opening wedge high tibial osteotomy for medial compartment knee osteoarthritis: Planning and improving outcomes: Case series and literature review

Double-level knee valgization osteotomy has high survivorship and a low complication rate in a single-center series of 58 cases with a mean clinical follow-up of 10 years

BACKGROUND

Double-level knee osteotomy (DLO) is becoming more popular in bifocal (femur and tibia deformities) as it addresses the deformity where it belongs and results in a more physiologic joint line obliquity. This study reports on the early to midterm outcomes, both clinical and radiological, of valgization DLO for varus knees and the first study to report the 10-year survivorship of this procedure.

METHODS

A retrospective review of a prospectively maintained single-center database of 1170 knee osteotomies was undertaken. Patients with bifocal (femur and tibia) varus malalignment and isolated medial compartment osteoarthritis who had DLO corrections [high tibial osteotomy (HTO) and distal femoral osteotomy (DFO)] were included. Multiple patient-reported outcome measures (PROMs) were recorded preoperatively and serially postoperatively. This included the Knee Injury and Osteoarthritis Outcome Score, the Oxford Knee Score, the Oxford Knee Score-Activity and Participation Questionnaire, the Western Ontario and McMaster University Score, the visual analog scale for health and pain, and the EQ-5D. EQ-5D stands for EuroQol 5-dimension. It is a standardized instrument for measuring health-related quality of life (HRQoL). All lower limb alignment indices were recorded pre-and postoperatively. The rates of osteotomy revision, conversion to arthroplasty, complications, and both 8- and 10-year survivorship were recorded.

RESULTS

A total of 58 valgization DLO cases were followed up to a mean of 10.8 ± 3 years. This comprised 74.1% males and 25.9% females, with a mean age of 47.9 ± 9.8 years and a mean body mass index (BMI) of 31.5 ± 6.3 kg/m2. The mean planned correction angles for HTO and DFO were 7.7° ± 2.7° and 7.7° ± 3°, respectively. Postoperatively, the mean mechanical tibiofemoral angle improved from -12.7° ± 3.9° (varus) to -0.4° ± 3.4° (i.e., centered around mechanical neutral), the mean medial proximal tibial angle improved from preoperative 84.3 ± 3.2° to postoperative 90° ± 2.5°, the mean mechanical lateral distal femoral angle improved from preoperative 91.6° ± 3.4° to postoperative 86.7° ± 2.5°, and the mean Mikulicz point improved from -5 ± 13.4% to 47.7 ± 14.7% (all p-values < 0.001). All PROMs significantly improved at 24 months follow-up (all p values < 0.001). The rate of osteotomy revision was 3.4%. The overall rate of total knee arthroplasty conversion was 5.2% at an average of 5.9 ± 3.1 years postoperatively. The complication rate was 8.6%. The 8- and 10-year survivorship was 97.1%, and 94.4%, respectively.

CONCLUSIONS

In this single-center series evaluating patients with varus knees and bifocal deformities, valgization double-level knee osteotomy (DLO) demonstrated favorable clinical outcomes, accompanied by a low complication rate of 8.6% and a 10-year survivorship of 94.4%. Radiographic findings from available imaging data were positive, although long-term imaging was not consistently obtained. Level of evidence IV retrospective cohort study.

Extra-articular Osteotomy for the Management of Intra-articular Tibial Plateau Valgus Malunion

OBJECTIVES

To report a case series of extra-articular osteotomies for the management of intra-articular tibial plateau malunions and to assess the ability to correct deformity and improve knee range of motion (ROM).

METHODS

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DESIGN

Retrospective case series.

SETTING

Academic, tertiary, referral center.

PATIENT SELECTION CRITERIA

Adult patients with tibial plateau fracture malunion treated with extra-articular osteotomy of the femur and/or tibia between 2014 and 2023.

OUTCOME MEASURES AND COMPARISON

Mechanical axis deviation (MAD), medial proximal tibia angle (MPTA), lateral distal femoral angle (LDFA), and posterior proximal tibia angle (PPTA) correction; knee ROM; and time to weight bearing.

RESULTS

There were 7 patients included, 6 (85.7%) were female and 1 (14.3%) were male. The median age was 43.5 years (IQR 38.5-51, range 32-62). Four (57.1%) patients were treated with a high tibial osteotomy (HTO), and 3 (42.9%) patients were treated with an HTO and distal femoral osteotomy. One patient had concomitant supramalleolar osteotomy with HTO to address distal tibia procurvatum and valgus. Four were treated with hexapod frames, and 3 were treated with plates and screws. Median follow-up was 22.5 months (IQR 10.5-107 months, range 7-148 months). Surgical intervention corrected median radiographic measures of valgus malalignment preoperatively relative to postoperative values. This included MAD (42.5 mm-0 mm), valgus angle (12.5 degrees-1.5 degrees), MPTA (95 degrees-88.0°), and LDFA (86.0°-87.3 degrees). Surgical intervention increased maximal knee range of motion preoperatively to postoperatively. Median time to full weight bearing was 81.5 days (IQR 46-57 days, range 41-184 days). Two patients were converted to total knee arthroplasty after 5 and 10 years following HTO with hexapod frame.

CONCLUSIONS

Extra-articular osteotomy is an effective treatment for addressing intra-articular malunion after tibia plateau fractures. It is effective in correcting the MAD, valgus deformity, MPTA, LDFA, PPTA, and improving knee ROM (measured through knee extension and flexion).

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Pre-operative Planning of High Tibial Osteotomy With ChatGPT: Are We There Yet?

INTRODUCTION

ChatGPT (Chat Generative Pre-trained Transformer), developed by OpenAI (San Francisco, CA, USA), has gained attention in the medical field. It has the potential to enhance and simplify tasks, such as preoperative planning in orthopedic surgery. We aimed to test ChatGPT's accuracy in measuring the angle of correction for high tibial osteotomy for cases planned and performed at a tertiary teaching hospital in Singapore.

MATERIALS AND METHODS

Peri-operative angular parameters from 114 consecutive patients who underwent medial opening wedge high tibial osteotomy (MOWHTO) were used to query ChatGPT 3.0. First ChatGPT 3.0 was queried on what information it required to plan a MOWHTO. Based on its response, pre-operative medial proximal tibial angle (MPTA) and joint line congruence angle (JLCA) were provided. ChatGPT 3.0 then responded with its recommended angle of correction. This was compared against the manually planned surgical correction by our fellowship-trained surgeon. A root mean square analysis was then performed to compare ChatGPT 3.0 and manual planning.

RESULTS

The root mean square error (RMSE) of ChatGPT 3.0 in predicting correction angle in MWHTO was 2.96, suggesting a very poor model fit.

CONCLUSION

Although ChatGPT 3.0 represents a significant breakthrough in large language models with extensive capabilities, it is not currently optimized to effectively perform complex pre-operative planning in orthopedic surgery, specifically in the context of MOWHTO. Further refinement and consideration of specific factors are necessary to enhance its accuracy and suitability for such applications.