A predictive score of high tibial osteotomy survivorship to help in surgical decision-making: the SKOOP score

Comparison of clinical outcomes among patients treated with high tibial osteotomy and meniscal repair of degenerative medial meniscal tear with mild varus deformity

INTRODUCTION

The clinical benefits of high tibial osteotomy (HTO) in patients with mild varus deformity with degenerative medial meniscal tear (DMMT) remain unclear. This study aimed to compare clinical outcomes among middle-aged patients with mild varus deformity who underwent arthroscopic meniscal repair and HTO for DMMT.

MATERIALS AND METHODS

In this retrospective study, patients who underwent isolated arthroscopic meniscal repair via the inside-out technique and those who underwent medial opening-wedge HTO were assigned to group M and H, respectively. The inclusion criteria were: an age of 40-65 years; percentage of mechanical axis of 30-50% measured using full-length weight-bearing anteroposterior radiographs; Kellgren-Lawrence grade ≤ 2; minimum postoperative two-year follow-up; and HTO correction angle < 10°. Clinical outcomes were assessed using the Knee Injury and Osteoarthritis Outcome Score (KOOS) and minimal clinically important difference achievement rate for the KOOS subscales preoperatively and at the final follow-up.

RESULTS

Group M and H included 21 and 41 patients, respectively. The median ages were 53 and 58 years in groups M and H, respectively. In group H, 24 cases underwent meniscal repair. No significant differences in all KOOS subscales were found preoperatively. However, the median KOOS symptoms subscale in group H (89.3) was significantly better than that in group M (80.4) at the final follow-up (p = 0.04).

CONCLUSION

The main finding of the study indicated that KOOS symptoms after HTO were superior to those after isolated arthroscopic meniscal repair for DMMT. HTO might be a potentially useful treatment for DMMT in middle-aged patients with mild varus deformity, even with a small correction angle.

LEVEL OF EVIDENCE

Retrospective comparative study, Level III.

An increased medial proximal tibial angle of greater than 95 degrees after opening wedge high tibial osteotomy is not associated with deterioration of minimum 10-year clinical outcomes

PURPOSE

The purpose of this study was to assess whether an excessively increased medial proximal tibial angle (MPTA) resulted in the deterioration of long-term clinical outcomes after opening wedge high tibial osteotomy (OWHTO) for patients with knee osteoarthritis (OA).

METHODS

A total of 69 OA knees that underwent OWHTO, with follow-up for a minimum of 10 years, were retrospectively reviewed. The knee and function scores of the Knee Society Score were assessed separately, and cases with a score decline greater than or equal to the minimal clinically important difference from postoperative 1 to 10 years were defined as showing clinical deterioration. Cartilage status was assessed with arthroscopy at the time of osteotomy (first-look) and plate removal (second-look) according to the International Cartilage Repair Society grading system. The outcomes were compared between knees with MPTA ≤ 95° (n = 27) and MPTA > 95° (n = 42).

RESULTS

The mean knee and function scores at postoperative 10 years in MPTA ≤ 95° knees (86.8 ± 9.6 and 90.4 ± 13.1) were not significantly different from those in MPTA > 95° knees (85.8 ± 11.5 and 86.9 ± 14.2). The rate of clinical deterioration in knee and function scores was not significantly different between MPTA ≤ 95° knees (26% and 26%) and MPTA > 95° knees (21% and 36%). No significant differences were found between the MPTA ≤ 95° and MPTA > 95° groups in the cartilage status of all compartments at both first-look and second-look (postoperative 21 months) arthroscopies.

CONCLUSIONS

Increased MPTA > 95° after OWHTO is not associated with deterioration of minimum 10-year clinical outcomes.

Higher conversion rate to knee arthroplasty in female patients following medial open-wedge high tibial osteotomy

PURPOSE

Most studies about medial open-wedge high tibial osteotomy (HTO) reported outcomes without focusing on gender differences. Therefore, the study compared the long-term survival rate and postoperative subjective knee function after HTO in female versus male patients with symptomatic medial compartment knee osteoarthritis.

METHODS

The data of three cohorts with long-term outcomes were analysed (n = 245; 32% females; age: 49 ± 7 years; Kellgren Lawrence Grade I 6.1%, II 32.7%, III 42.4%; IV 18.8%). The minimum follow-up was at least 6 years or an earlier conversion to total knee arthroplasty (TKA). The gender-specific survival rate after HTO was calculated after 5 and 10 years and compared using Kaplan-Meier analysis and the logrank test. Baseline characteristics and subjective knee function (International Knee Documentation Committee [IKDC]/Lysholm) were analysed between both genders.

RESULTS

Forty of 78 (51.3%) women and 41 of 167 men (24.5%) underwent TKA. HTO survival in females was significantly lower (p = 0.0010). The 5- and 10-year survival rates were 85.9% and 62.6% for females and 93.4% and 77.7% for males. In females and males, from preoperative to the last follow-up, the IKDC (43 ± 15 to 58 ± 17; 47 ± 14 to 67 ± 18) and the Lysholm (42 ± 18 to 72 ± 18; 55 ± 22 to 77 ± 23) improved significantly (all p < 0.0001). Females had significantly lower preoperative and postoperative IKDC (p = 0.0438; p = 0.0035) and Lysholm scores (p = 0.0002; p = 0.0323). But the absolute improvements of the IKDC and Lysholm were not significantly different between genders.

CONCLUSIONS

Females had higher conversion rates to TKA and lower knee function at the last follow-up. However, preoperative knee function was lower in females and the absolute improvement following HTO was similar for both genders. In general, females benefit from HTO to treat medial knee arthritis, and TKA could be postponed for half of female patients for more than 10 years. However, surgeons must be aware of the described inferior outcomes in females for realistic patient expectation management.

LEVEL OF EVIDENCE

Level II.

High survivorship rate and good clinical outcomes after high tibial osteotomy in patients with radiological advanced medial knee osteoarthritis: a systematic review

INTRODUCTION

The role of valgus producing high tibial osteotomy (HTO) for the treatment of advanced knee osteoarthritis (OA) is still controversial. The aim of the current systematic review was to assess survivorship and patient-reported outcomes (PROMs) of high tibial osteotomy in patients with radiological advanced medial knee OA.

METHODS

A systematic search of PubMed, Cochrane and EMBASE database was performed in July 2023 in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) guidelines. Inclusion and exclusion criteria were applied to identify studies investigating the survivorship rate and PROMs of valgus-producing high tibial osteotomy in patients with advanced knee OA at x-ray assessment in the medial compartment at minimum-two-years follow up. Advanced radiological OA was defined as Kellgren Lawrence (K-L) ≥ 3 or Ahlbäch ≥ 2. Survivorship was defined as percentage of patients free of total knee arthroplasty (TKA) at follow-up. Clinical interpretation of provided PROMs were performed according to minimal clinically important difference (MCID) and patient acceptable symptom state (PASS) target values reported in literature. Survivorship data and PROMs scores were extracted, and studies were stratified based on selected study features. The quality of included studies was assessed with modified Coleman score.

RESULTS

A total of 18 studies, totalling 1296 knees with a mean age between 46.9 and 67 years old, were included. Average survivorship was of 74.6% (range 60 - 98.1%) at 10-years follow up. The subjective scoring systems showed good results according to MCID and PASS, and postoperative improvements were partially maintained until final follow-up.

CONCLUSION

HTO is worth considering as treatment choice even in patients affected by radiological advanced medial knee osteoarthritis. Long term survivorship and good patient reported clinical outcomes could be expected in this population.

LEVEL OF EVIDENCE

IV; systematic review of level III-IV studies.

Factors to improve odds of success following medial opening-wedge high tibial osteotomy: a machine learning analysis

BACKGROUND

Although high tibial osteotomy (HTO) is an established treatment option for medial compartment osteoarthritis, predictive factors for HTO treatment success remain unclear. This study aimed to identify informative variables associated with HTO treatment success and to develop and internally validate machine learning algorithms to predict which patients will achieve HTO treatment success for medial compartmental osteoarthritis.

METHODS

This study retrospectively reviewed patients who underwent medial opening-wedge HTO (MOWHTO) at our center between March 2010 and December 2015. The primary outcomes were a lack of conversion to total knee arthroplasty (TKA) and achievement of a minimal clinically important difference of improvement in the Knee Injury and Osteoarthritis Outcome Score (KOOS) at a minimum of five years postoperatively. Recursive feature selection was used to identify the combination of variables from an initial pool of 25 features that optimized model performance. Five machine learning algorithms (XGBoost, multilayer perception, support vector machine, elastic-net penalized logistic regression, and random forest) were trained using five-fold cross-validation three times and applied to an independent test set of patients. The performance of the model was evaluated by the area under the receiver operating characteristic curve (AUC).

RESULTS

A total of 231 patients were included, and 200 patients (86.6%) achieved treatment success at the mean of 9 years of follow-up. A combination of seven variables optimized algorithm performance, and the following specific cutoffs increased the likelihood of MOWHTO treatment success: body mass index (BMI) ≤ 26.8 kg/m2, preoperative KOOS for pain ≤ 46.0, preoperative KOOS for quality of life ≤ 33.0, preoperative International Knee Documentation Committee score ≤ 42.0, preoperative Short-Form 36 questionnaire (SF-36) score > 42.25, three-month postoperative hip-knee-ankle angle > 1.0°, and three-month postoperative medial proximal tibial angle (MPTA) > 91.5° and ≤ 94.7°. The random forest model demonstrated the best performance (F1 score: 0.93; AUC: 0.81) and was transformed into an online application as an educational tool to demonstrate the capabilities of machine learning.

CONCLUSIONS

The random forest machine learning algorithm best predicted MOWHTO treatment success. Patients with a lower BMI, poor clinical status, slight valgus overcorrection, and postoperative MPTA < 94.7 more frequently achieved a greater likelihood of treatment success.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

20-Year Outcomes of High Tibial Osteotomy: Determinants of Survival and Functional Outcome

BACKGROUND

High tibial osteotomy (HTO) is a successful joint-preserving procedure for the treatment of medial compartment osteoarthritis. Long-term survivorship of HTO ranges from 40% to 85%. There are consistent factors that predict failure.

PURPOSE

To determine the 20-year survival of HTO and identify predictors of failure.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A total of 100 consecutive patients with medial bone-on-bone arthritis were prospectively studied to provide long-term patient-reported outcome measures after lateral closing-wedge HTO and determine the time to failure. Failure was defined as conversion to arthroplasty (total knee arthroplasty or unicompartmental knee arthroplasty) or revision HTO.

RESULTS

At 20 years, HTO survival was determined in 95 patients, and 5 were lost to follow-up. The overall survivorship of HTO at 20 years was 44%. The significant factors that were associated with better survivorship were age <55 years, body mass index <30, and Western Ontario and McMaster Universities Osteoarthritis Index pain score >45. These factors were used to define the favorable candidates. In the favorable candidates, survivorship was 100% at 5 years, after which there was a gradual decline to 62% survival at 20 years. Of those with HTO survival, 32 of 33 (97%) reported satisfaction with surgery, with a mean Knee injury and Osteoarthritis Outcome Score Pain score of 91 and Activities of Daily Living score of 97.

CONCLUSION

HTO is a successful surgical option to treat medial compartment osteoarthritis and prevent the need for arthroplasty in young patients. The most suitable candidates for HTO are aged <55 years, are not obese, and have not progressed to severe symptomatic disability.