Joint Space Width Increases Medially and Decreases Laterally at Different Time Points After Medial Open-Wedge High Tibial Osteotomy

Association Between Joint Line Convergence Angle and Patient-Reported Outcomes of Opening-Wedge High Tibial Osteotomy

BACKGROUND

A larger joint line convergence angle (JLCA) increases the stress load on the medial compartment. Few reports, however, have discussed the effect of the JLCA on the cartilage status and clinical outcomes after opening-wedge high tibial osteotomy (OWHTO).

PURPOSE/HYPOTHESIS

To reveal the effect of the JLCA on clinical results after OWHTO. We hypothesized that a smaller JLCA improves cartilage status and clinical outcomes by reducing mechanical stress in the medial compartment.

STUDY DESIGN

Cohort study: Level of evidence, 3.

METHODS

This retrospective study included 106 knees that underwent OWHTO and second-look arthroscopy during implant removal 1 year after OWHTO. The mean follow-up period was 5.5 (SD, 2.9) years. The pre- and postoperative JLCAs were measured radiographically. The International Cartilage Repair Society (ICRS) grades of the medial femoral condyle (MFC) and the medial tibial plateau (MTP) were evaluated during the initial and second-look arthroscopy. The relationship between the JLCA and cartilage status, and the Knee injury and Osteoarthritis Outcome Score (KOOS) at the final follow-up were evaluated.

RESULTS

Preoperative JLCA was related to improvements in the ICRS grade of the MFC and the MTP, with cutoff values of 2.6° (sensitivity, 0.700; specificity, 0.561; P = .016) and 2.4° (sensitivity, 0.704; specificity, 0.595; P = .028), respectively. In addition, the preoperative JLCA was related to KOOS Pain (P = .037), Symptoms (P < .001), Activities of Daily Living (P = .005), Sports Activities (P = .005), and Quality of Life (P = .006) subscales using multivariable linear regression analysis. The postoperative JLCA was not related to the improvement in the ICRS grade of the MFC but was related to the improvement in the ICRS grade of the MTP, with a cutoff value of 1.6° (sensitivity, 0.704; specificity, 0.603; P = .015). Furthermore, postoperative JLCA was related to the KOOS Pain (P = .004), Symptoms (P = .002), Activities of Daily Living (P = .031), Sports Activities (P < .001), and Quality of Life (P = .015) subscales.

CONCLUSION

A smaller pre- and postoperative JLCA was related to improvements in the ICRS grade and favorable clinical outcomes, with a mean 5.5-year follow-up after OWHTO.

Comparative outcomes of proximal fibular osteotomy versus high tibial osteotomy in patients with medial knee osteoarthritis: A retrospective analysis

High tibial osteotomy (HTO) is a widely used procedure for delaying knee arthroplasty, correcting alignment, and relieving symptoms in patients with knee osteoarthritis. Recently, proximal fibular osteotomy (PFO) has emerged as a less invasive and more cost-effective alternative. This study compares the outcomes of HTO and PFO to evaluate whether PFO can deliver results comparable to HTO in similar patient populations. A total of 96 patients treated between 2018 and 2022 were analyzed, with 54 patients undergoing HTO and 42 undergoing PFO. Subgroups were also created based on body mass index (BMI): non-obese HTO, obese HTO, non-obese PFO, and obese PFO. For each patient, we recorded demographic data, preoperative and 1-year postoperative Oxford Knee Scores (OKS), visual analog scale (VAS) scores, medial joint space (MJS) measurements, mechanical axis deviations (MAD), Kellgren- Lawrence grade (KL), medial proximal tibial angle (MPTA), and any complications. Both HTO and PFO led to significant improvements in OKS, VAS, MJS width, and MAD. Age, KL grade distribution, BMI, and MPTA values were comparable across the groups. Overall, HTO showed superior clinical (OKS, VAS) and radiological (MJS, MAD) outcomes, particularly in non-obese patients. Among obese patients, HTO and PFO achieved similar clinical improvements, although HTO maintained a radiological advantage. Importantly, a lower preoperative MPTA was associated with poorer clinical outcomes in the PFO group. In conclusion, while PFO can produce meaningful clinical and radiological improvements, HTO remains the more effective option in terms of both clinical and radiological outcomes in patients with a BMI below 30. For patients with a BMI over 30, HTO preserves its radiological superiority, although its clinical benefits are comparable to those of PFO. Additionally, a low preoperative MPTA is significantly linked to worse OKS scores in patients undergoing PFO.

Effect of Meniscal Tear Patterns and Preoperative Cartilage Status on Joint Space Width After Medial Opening-Wedge High Tibial Osteotomy

BACKGROUND

Medial opening-wedge high tibial osteotomy (MOWHTO) is performed to treat young adults with medial compartment knee osteoarthritis associated with varus deformity. However, factors influencing joint space width (JSW) vary according to the type of medial meniscal tear and have not yet been completely elucidated.

PURPOSE

To examine changes in JSW according to the type of medial meniscal tear after MOWHTO and analyze the influencing factors.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

This study was conducted on 134 patients who underwent MOWHTO for medial osteoarthritis and were followed up for >2 years. The patients were classified into 3 groups based on medial meniscal status: intact, nonroot tear, and root tear. The authors then measured the JSW preoperatively and at 3 months, 6 months, 1 year, and >2 years postoperatively; analyzed whether the change in JSW varied according to meniscal status; and determined the association of these changes with the preoperative cartilage grade of the medial femoral condyle (MFC) and medial tibial plateau (MTP). International Knee Documentation Committee (IKDC) scores were used to evaluate clinical function.

RESULTS

Of the 134 patients, the medial meniscus was intact in 29 patients, a nonroot tear was observed in 58 patients, and a root tear was observed in 47 patients. Postoperatively, JSW increased for all groups, but the timing of the increase varied between the groups (P < .001). JSW increased the most 6 months postoperatively in the intact group and 3 months postoperatively in the nonroot tear and root tear groups (P < .001). Additionally, the increase in JSW was the greatest in the root tear group. Preoperatively, MFC and MTP cartilage status differed among the groups; MTP status did not affect the JSW, but MFC status did (P < .001). The IKDC score increased from the preoperative to postoperative time point in all groups, but there was no significant difference between groups.

CONCLUSION

The authors observed that the amount and timing of increase in JSW were dependent on the pattern of medial meniscal tear observed when MOWHTO was performed. In addition, the cartilage grade of MFC before surgery was associated with changes in JSW. The IKDC score was not significantly different between groups. However, a longer follow-up period is needed to analyze the correlation with the meniscal tear pattern and JSW.

Adipose-Derived Stromal Vascular Fractions Are Comparable With Allogenic Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells as a Supplementary Strategy of High Tibial Osteotomy for Varus Knee Osteoarthritis

Purpose

To compare the clinical, radiologic, and second-look arthroscopic outcomes of high tibial osteotomy (HTO) with stromal vascular fraction (SVF) implantation versus human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSC) transplantation and identify the association between cartilage regeneration and HTO outcomes.

Methods

Patients treated with HTO for varus knee osteoarthritis between March 2018 and September 2020 were retrospectively identified. In this retrospective study, among 183 patients treated with HTO for varus knee osteoarthritis between March 2018 and September 2020, patients treated with HTO with SVF implantation (SVF group; n = 25) were pair-matched based on sex, age, and lesion size with those who underwent HTO with hUCB-MSC transplantation (hUCB-MSC group; n = 25). Clinical outcomes were evaluated using the International Knee Documentation Committee score and Knee Injury and Osteoarthritis Outcome Score. Radiological outcomes evaluated were the femorotibial angle and posterior tibial slope. All patients were evaluated clinically and radiologically before surgery and during follow-up. The mean final follow-up periods were 27.8 ± 3.6 (range 24-36) in the SVF group and 28.2 ± 4.1 (range, 24-36) in the hUCB-MSC group (P = 0.690). At second-look arthroscopic surgery, cartilage regeneration was evaluated using the International Cartilage Repair Society (ICRS) grade.

Results

A total of 17 male and 33 female patients with a mean age of 56.2 years (range, 49-67 years) were included. At the time of second-look arthroscopic surgery (mean, 12.6 months; range, 11-15 months in the SVF group and 12.7 months; range, 11-14 months in the hUCB-MSC group, P = .625), the mean International Knee Documentation Committee score and Knee Injury and Osteoarthritis Outcome Score in each group significantly improved (P < .001 for all), and clinical outcomes at final follow-up further improved in both groups when compared with the values at second-look arthroscopic surgery (P < .05 for all). Overall ICRS grades, which significantly correlated with clinical outcomes, were similar between groups with no significant differences (P = .170 for femoral condyle and P = .442 for tibial plateau). Radiologic outcomes at final follow-up showed improved knee joint alignment relative to preoperative conditions but showed no significant correlation with clinical outcomes or ICRS grade in either group (P > .05 for all).

Conclusions

Improved clinical and radiological outcomes and favorable cartilage regeneration were seen after surgery for varus Knee OA in both SVF and hUCB-MSC groups.

Level of Evidence

Level III, retrospective comparative study.

Analysis of the determinant factor of the medial joint space width after medial opening wedge high tibial osteotomy

INTRODUCTION

The decrease in the medial joint space width (MJSW) in patients with osteoarthritis (OA) is proportional to the degree of arthritis. The purpose of this study was to evaluate the affecting factors of the MJSW by serial radiologic assessment after medial open wedge high tibial osteotomy (MOW-HTO).

MATERIALS AND METHODS

Between March 2014 and March 2019, 162 MOW-HTO knees that underwent serial radiologic assessment and follow-up MRI were enrolled. Changes in the MJSW were analyzed by dividing into three groups: group I, low quartile (< 25%); II, middle quartile (25-75%); and III, high quartile (> 75%), according to the magnitude of the MJSW. The correlation between the MJSW and weight-bearing line ratio (WBLR), hip knee ankle angle (HKA), joint line convergence angle (JLCA), medial proximal tibial angle (MPTA), mechanical lateral distal femoral angle (m-LDFA), joint line orientation angle (JLOA), and MRI cartilage status was analyzed. Multiple linear regression analysis was used to analyze factors affecting the amount of change in the MJSW. The clinical outcome was also correlated with the MJSW.

RESULTS

The amount of change in the JLCA, which has the largest beta value (weight-bearing standing anteroposterior (AP) view and 45° flexion posteroanterior view (Rosenberg view) β =  - 0.699 and β = -5.221, both p < 0.001, respectively), had the greatest contribution to the change in the MJSW. The WBLR was also related (standing AP and Rosenberg β = 0.177 and β = 0.264, p = 0.015 and p = 0.004, respectively). There was no statistical difference between the amount of change in the MJSW and the change in cartilage. The clinical outcomes did not differ between the groups.

CONCLUSION

The JLCA was the most important contributing factor for the MJSW, followed by WBLR. This contribution was more pronounced in Rosenberg view than standing AP view. Changes in cartilage status were not related to the MJSW and JLCA. The clinical outcome was not related to the MJSW, either. Level of evidence Cohort study; level III.

Editorial Commentary: Early Postoperative Knee Joint Space Width Change Is Attributable to Change in the Joint Line Convergence Angle After High Tibial Osteotomy and May Not Reflect Cartilage Regeneration

Realignment of the weightbearing axis by high tibial osteotomy (HTO) can alter the forces acting on the articular cartilage within the knee, reducing the load on the medial compartment. This unloading effect is thought to allow the repair of the articular cartilage of the affected compartment. It is important to evaluate the serial changes of joint space width (JSW) after HTO for assessing the state of the cartilage and the unloading effect by HTO. However, early postoperative knee JSW change is attributable to change in the joint line convergence angle after HTO and may not reflect cartilage regeneration. In addition, the soft tissue laxity of the knee and changes in joint line convergence angle after HTO should be considered for assessing these early postoperative JSW changes.