Serial Improvement of Medial Meniscus Extrusion Following Medial Open-Wedge High Tibial Osteotomy Does Not Correlate With Clinical Outcomes and Arthroscopic Articular Cartilage Improvement

High tibial osteotomy alone does not decrease medial meniscus extrusion in the setting of medial meniscus posterior root tear: A cadaveric study

PURPOSE

This study investigated whether inducing valgus alignment and shifting the load laterally through high tibial osteotomy (HTO) alone decreases the extent of medial meniscus extrusion (MME) in the setting of medial meniscus posterior root tear(MMPRT) using ultrasound evaluation.

METHODS

Eight fresh-frozen human cadaveric knee specimens were tested using a six-degree-of-freedom robotic testing system and ultrasound. Each specimen was tested in five conditions: (1) intact, (2) MMPRT, (3) medial meniscus repair (MMR), (4) combined medial open-wedge HTO + MMR, and (5) HTO + MMPRT. Measurements were obtained over the medial collateral ligament (MCL, central image) and posterior to the MCL (posterior image) with a 250 N axial load at 0°, 30°, and 90° of knee flexion. Statistical analysis was performed using a two-factor repeated-measures ANOVA.

RESULTS

MME was significantly greater in HTO + MMPRT(0°: 2.44 ± 0.41mm, 30°: 2.47 ± 0.37mm, 90°: 2.41 ± 0.28mm) than HTO + MMR in central images (mean difference +0.83 mm, p < .001). No significant difference was found between HTO + MMPRT and MMPRT in MME . MMR had significantly less MME than MMPRT (mean difference -0.58mm, p < .001, posterior image at 0°and central image at 90°, p=.002). HTO + MMR showed significantly less MME than MMR alone at 30° and 90° knee flexion in central image (30°: -0.38 ± 0.05mm, 90°: -0.45 ± 0.06mm, p < .001) and 90° knee flexion in posterior image (-0.38 ± 0.08mm, p = .004).

CONCLUSION

HTO alone did not decrease MME in the setting of MMPRT, while MMR alone decrease MME after MMPRT. Additionally, HTO + MMR decreases MME aftrer MMPRT compared to MMR alone, although the clinical significance was uncertain.

CLINICAL RELEVANCE

The findings of this study provide clinicians with valuable insights for improving MME. HTO alone does not decrease MME in cases of MMPRT.

Implant Removal After Medial Opening Wedge High Tibial Osteotomy Provides Implant-Related Pain Relief and Functional Improvement

PURPOSE

To investigate the incidence of implant-related pain after medial opening wedge high tibial osteotomy (MOWHTO) using a locking plate, to determine whether implant removal provides pain relief and functional improvement, and to evaluate bone healing and loss of correction after implant removal.

METHODS

Between March 2014 and September 2017, MOWHTO was performed without bone graft. The inclusion criteria were patients who underwent implant removal after MOWHTO and were followed up for a minimum of 2 years. Patients were evaluated for implant removal 1 and 2 years after surgery. Clinical and functional evaluations were conducted to investigate implant-related pain using the visual analog scale, Lysholm score, and Tegner score. The radiographic indices measured were the gap-filling rate, weightbearing line (WBL) ratio, hip-knee-ankle angle (HKAA), medial proximal tibial angle (MPTA), and posterior tibial slope angle (PTSA).

RESULTS

A total of 55 patients were enrolled. Fifty-one (92.7%) patients experienced implant-related pain prior to implant removal, with 43 and 8 patients reporting mild pain and moderate pain, respectively. At 1 and 2 years after implant removal, mild pain occurred in 6 (10.9%) and 5 (9.1%) patients, respectively. The remaining patients reported no implant-related pain. Prior to implant removal and 1 year after implant removal, the Lysholm score improved from 77.0 ± 5.6 to 86.8 ± 5.7 (P < .001), and the Tegner score improved from 3.3 ± 1.2 to 3.9 ± 1.3 (P < .001). The mean gap-filling rate was 84.4% ± 9.6% at implant removal, and it significantly increased to 93.7% ± 5.4% and 97.4% ± 2.6% at 1 and 2 years after implant removal, respectively (P < .001). For the WBL ratio, HKAA, MPTA, and PTSA, no statistically significant differences were found after implant removal.

CONCLUSIONS

The incidence of implant-related pain after MOWHTO using the medial proximal tibial locking plate was high. Implant removal provides pain relief and functional improvement (met minimal clinically important differences). Even after implant removal, bone healing progressed gradually without a loss of correction in all patients.

LEVEL OF EVIDENCE

Level IV, case series.

Cartilage Degeneration of the Lateral Compartment of the Knee at Second-Look Arthroscopy Is Associated With Deterioration of 10-Year Clinical Outcomes After Opening-Wedge High Tibial Osteotomy

PURPOSE

To identify the arthroscopic findings associated with deterioration of 10-year clinical outcomes after opening-wedge high tibial osteotomy (OWHTO) in patients with knee osteoarthritis.

METHODS

A total of 114 consecutive knees of 91 patients with knee osteoarthritis who underwent OWHTO between 2007 and 2011 were retrospectively reviewed. Of these patients, those who underwent second-look arthroscopy and were followed up for a minimum of 10 years were enrolled. The Knee Society Score (KSS) and hip-knee-ankle angle were assessed. Cartilage status was graded at the time of osteotomy (first look) and plate removal (second look) according to the International Cartilage Repair Society (ICRS) grading system. The KSS knee subscale score and function subscale score were assessed separately, and on the basis of the changes in each of these scores from 1 to 10 years postoperatively and the minimal clinically important difference (MCID), the patients were divided into 2 groups: deteriorated (deterioration of score ≥ MCID) and non-deteriorated (deterioration of score < MCID).

RESULTS

Sixty-nine knees were included in this study. The mean knee score improved continuously from 48.7 ± 11.3 preoperatively to 86.8 ± 10.3 at 1 year (P < .001), 87.5 ± 9.9 at 5 years (P < .001), and 86.5 ± 10.5 at 10 years (P < .001) postoperatively. The mean function score also improved continuously from 62.5 ± 12.1 preoperatively to 90.7 ± 12.9 at 1 year (P < .001), 91.6 ± 12.1 at 5 years (P < .001), and 88.5 ± 13.1 at 10 years (P < .001) postoperatively. Three knees underwent conversion to total knee arthroplasty within 10 years postoperatively. The deteriorated KSS group showed significantly progressed ICRS grades in the lateral compartment compared with the non-deteriorated KSS group. The ICRS grade in the lateral compartment at second-look arthroscopy was identified as the only significant factor associated with both knee score deterioration (odds ratio, 4.89; P = .03) and function score deterioration (odds ratio, 3.91; P = .03) on multivariable logistic regression analysis.

CONCLUSIONS

The presence of cartilage degeneration of the lateral compartment of the knee at second-look arthroscopy is associated with deterioration of long-term clinical outcomes after OWHTO.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Effect of limb alignment correction on medial meniscus extrusion under loading condition in high tibial osteotomy

Background

This study aimed to investigate the effect of high tibial osteotomy (HTO) on medial meniscus extrusion (MME) and the association between the changes in limb alignment and MME under weight-bearing (WB) conditions after HTO.

Methods

We included 17 patients with knee osteoarthritis (OA) who underwent HTO. MME was evaluated using ultrasonography in supine and unipedal standing positions. Knee alignment was evaluated radiographically using WB, whole-leg radiographs with the hip-knee-ankle angle (HKAA), percentage of the mechanical axis (%MA), medial proximal tibial angle (MPTA), and joint line convergence angle (JLCA). All measurements were performed serially at four time points: preoperative and 3, 6, and 12 months postoperative. Clinical outcomes were assessed by knee injury and osteoarthrosis outcome score (KOOS) and visual analogue scale (VAS) value for pain.

Results

Mean MME in the WB position was significantly greater than that in the supine position in the preoperative condition; however, MME in both supine and WB positions was significantly lowered postoperatively. The ΔMME, difference of MME between supine and WB positions, was significantly lowered postoperatively and maintained for up to 1 year. MME change in the WB position between preop and postoperative conditions was significantly correlated with change in HKAA and %MA at 1 year postoperative. KOOS and VAS score were significantly improved after HTO.

Conclusions

HTO correcting varus alignment can decrease MME in WB position and minimise the change in MME between supine and WB positions. The changes in MME after HTO were correlated with changes in the mechanical alignments.

Increased medial meniscus extrusion led to worse clinical outcomes after medial opening-wedge high tibial osteotomy

PURPOSE

Given that no studies have assessed the correlation between improvements in medial meniscus extrusion (MME) and clinical outcomes after medial opening-wedge high tibial osteotomy (MOWHTO), the present study aimed to measure the improvement in MME after MOWHTO and to investigate the correlation between the remaining postoperative MME and MOWHTO clinical outcomes by subgroup analysis.

METHODS

This study included 79 patients (80 knees) who underwent MOWHTO with a minimum follow-up of 2 years. MME was measured pre- and postoperatively through magnetic resonance imaging after an average of 19.8 months following MOWHTO surgery. Clinical outcomes were evaluated according to the Knee Injury and Osteoarthritis Outcome Score (KOOS), the Tegner Activity Scale, and the Short-Form 36 questionnaire. In subgroup analysis, postoperative MME was classified into non-pathologic (≤ 3 mm) and pathologic (> 3 mm) groups. The clinical outcomes of the two groups were compared using Mann-Whitney U tests. A regression analysis was performed to determine the preoperative and postoperative characteristics associated with the improvement of MME.

RESULTS

The mean (± standard deviation) values for pre- and postoperative MME were 3.6 (± 1.8) mm and 2.8 (± 1.5) mm, respectively (p < 0.001). In the subgroup analysis of postoperative MME, the non-pathologic group showed better improvement of KOOS than the pathologic group. Preoperative hip-knee-ankle angle was correlated with the improvement of medial meniscal extrusion in both univariate (p = 0.049) and multivariate (p = 0.015) analyses.

CONCLUSION

The MME improved after MOWHTO, and the clinical outcomes were better for patients with a postoperative MME of less than 3 mm than for those with more than 3 mm. MME improvement after MOWHTO was correlated with preoperative varus alignment of the lower extremities.

LEVEL OF EVIDENCE

III (Retrospective cohort study).

Does Degeneration of the Patellofemoral Joint After Medial Open-Wedge High Tibial Osteotomy Affect Clinical Outcomes?

BACKGROUND

Although biomechanical and clinical studies have reported adverse effects on the patellofemoral joint after medial open-wedge high tibial osteotomy (MOWHTO), there is a paucity of literature that describes outcomes longer than midterm follow-up.

PURPOSE

We aimed to evaluate the mid- to long-term radiologic and clinical outcomes of the patellofemoral joint after MOWHTO and to assess whether radiologic deterioration of the patellofemoral joint affected clinical outcomes or survivorship after MOWHTO.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

We retrospectively reviewed 170 knees that underwent MOWHTO and had a minimum 5-year follow-up. In radiologic evaluation, serial postoperative changes in the patellofemoral joint compared with the preoperative status were evaluated on the Merchant view according to the Kellgren-Lawrence grade. The American Knee Society (AKS) score, Knee injury and Osteoarthritis Outcome Score (KOOS), Kujala score, incidence of anterior knee pain, and survivorship were used to assess clinical outcomes. Using radiologic assessment of the patellofemoral joint, we divided the patients into a radiologic progression group and a radiologic nonprogression group to evaluate whether radiologic progression of patellofemoral arthritis affected long-term clinical outcomes and survivorship after MOWHTO.

RESULTS

The mean follow-up period was 96.3 months (range, 60-163 months). Arthritic progression of the patellofemoral joint on the Merchant view was observed in 44.9%, 56.3%, 66.0%, and 84.0% of the cases at 5, 7, 9, and 11 years, respectively. Clinical outcomes such as AKS scores and KOOS significantly improved after MOWHTO (P < .001) at the latest follow-up. The incidence of anterior knee pain was 5.3% (9/170 knees). One knee (0.6%) underwent conversion to TKA due to progressive medial osteoarthritis, so the survival rate was 99.4% at a mean follow-up of 96.3 months. Despite patellofemoral degeneration over time, there were no significant differences in clinical outcomes or survivorship between patients with and without radiologic progression at the latest follow-up.

CONCLUSION

Although degeneration of the patellofemoral joint was observed with time after MOWHTO, the related symptoms were minimal and arthritic changes in the patellofemoral joint did not affect the clinical outcomes or survivorship after MOWHTO over a mid- to long-term follow-up.