Survival and Risk Factor Analysis of Medial Open Wedge High Tibial Osteotomy for Unicompartment Knee Osteoarthritis.

PURPOSE: The purpose of this retrospective study was to evaluate the survival rates and analyze the factors that affect survival rate after primary treatment with medial open wedge high tibial osteotomy (MOWHTO) for medial unicompartmental knee osteoarthritis. METHODS: Clinical evaluation using Knee Society Score (KSS) and Western Ontario and McMaster Universities Osteoarthritis Index score and radiographic evaluation, including mechanical axis, were done before and after surgery. The main failure criteria for survival included the conversion to total knee arthroplasty or KSS of <60 points. Furthermore, risk factors that affected the survival after MOWHTO were analyzed. RESULTS: Three hundred thirty-nine knees were included after a minimum of 5 years' follow-up. Their mean age was 56 years, and mean follow-up duration was 9.6 years. The mean KSS and Western Ontario and McMaster Universities Osteoarthritis Index scores were significantly improved after surgery (87.3 and 18.5 points at 5 years and 81.7 and 23.6 points at 10 years). The mean hip-knee-ankle (HKA) angle was corrected from 7.2° varus to 3.4° valgus 1 year after surgery, which was maintained until 10 years after surgery (2.9° valgus at 5 years and 2.3° valgus at 10 years, P > .05). Using Kaplan-Meier survival estimates, the probability of survival for MOWHTO was 96.8% at 5 years, 87.1% at 10 years, and 85.3% at 13 years. The multivariate regression analysis revealed that age ≥65 years (hazard ratio [HR] = 2.34, P = .046), medial compartment cartilage damage International Cartilage Repair Society grade ≥4 (HR = 2.46, I = .045), lateral compartment cartilage damage International Cartilage Repair Society grade≥2 (HR = 3.38, P = .006), postoperative HKA angle <0° (HR = 4.69, P < .001) were associated with failure. CONCLUSION: MOWHTO seems to be a good treatment option for young and active patients with medial knee osteoarthrosis and varus alignment, with acceptable survival rates and satisfactory outcomes. Age ≥65 years, grade 4 cartilage damage in medial compartment, grade ≥2 cartilage damage in lateral compartment, and undercorrection of HKA angle appear to be significant risk factors associated with failure. LEVEL OF EVIDENCE: Level IV: retrospective case series.

Treatment outcome of dome osteotomy of the pelvis combined with trochanteric advancement for sequelae of Perthes' disease.

OBJECTIVE: Disparity in size between femoral head and acetabulum could promote premature degeneration of the hip joint. The purpose of this study was to report the results of Kawamura's dome osteotomy for acetabular dysplasia due to sequelae of Perthes' disease. PATIENTS AND METHODS: Fourteen patients (14 hips) operated between 1999 and 2012 were retrospectively reviewed. There were 9 males and 5 females with a mean age of 29 years (range, 15-54 years). Functional and radiological results were reviewed at mean follow-up of 9 years (range, 4-12 years). RESULTS: Pain relief was obtained in 13 of 14 (92.8%) patients postoperatively. Good to excellent functional outcome was obtained in 10 of 14 (71.4%) patients. Mean Harris hip score was improved from 63 to 84 (p < 0.05) at the final follow-up. Improvement of limping gait was observed in 10 of 14 (71.4%) patients. Center edge angle improved from mean 24° (11-36°) preoperatively to mean 35° (27-46°) postoperatively (p < 0.05), acetabular angle improved from mean 43° (36-49°) preoperatively to mean 37° (32-44°) postoperatively (p < 0.05), acetabular head index improved from mean 69% (50-83%) preoperatively to mean 85% (73-100%) postoperatively (p < 0.05). Progression of arthrosis stage occurred in 3 of 14 (21%) patients. None of the hip with preoperative Stulberg III, 2 of 9 hips with Stulberg IV and 2 of 2 hips with Stulberg V needed conversion to total hip arthroplasty during the follow-up. CONCLUSION: Dome osteotomy of the pelvis combined with trochanteric advancement could give a reasonable treatment outcome for acetabular dysplasia due to Perthes' disease at mid to long-term follow-up. Advanced stage of arthrosis, preoperative Stulberg V and no improvement of limping gait after the surgery possibly associated with poor outcome. LEVEL OF EVIDENCE: Level IV, therapeutic study.