Clinical Results and Prognostic Factors for Outcomes of Valgus Femoral Osteotomy Combined with Chiari Pelvic Osteotomy for Osteoarthritis of the Hip

Abstract

Background: Surgeons have long debated whether advanced or end-stage osteoarthritis of the hip in young patients should be treated with total hip arthroplasty or osteotomy. We reviewed the intermediate-term clinical results of valgus femoral osteotomy combined with Chiari pelvic osteotomy (VCO) for advanced or end-stage osteoarthritis associated with severe acetabular dysplasia of the hip in young patients and analyzed prognostic factors related to conversion to total hip arthroplasty.

Methods: The study group included 54 hips in 50 patients (5 men and 45 women; average age at the time of surgery, 45.6 years). The minimum and average durations of follow-up were 10 and 17.6 years, respectively. The Japanese Orthopaedic Association hip score (JOA score) was used for clinical evaluation. The probability of survival of the VCO from the time of the operation until the end point of conversion to total hip arthroplasty was calculated with use of the Kaplan-Meier method. We defined prognostic factors of outcome (conversion to total hip arthroplasty) with the Cox proportional hazards model.

Results: The mean total JOA score increased from 53.0 points preoperatively to 77.1 points at 1 year postoperatively, 81.6 points at 5 years, and 76.8 points at 10 years. The survival rates were 83.3%, 59.7%, and 46.9% at 10, 15, and 20 years, respectively. On univariate and multivariate analyses, patients with a low degree of acetabular roof obliquity had better postoperative results.

Conclusions: VCO is a surgical approach that preserves joint function in young patients with advanced or end-stage osteoarthritis associated with severe acetabular dysplasia of the hip. The postoperative prognosis of VCO was improved in patients with a low degree of acetabular roof obliquity.

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

Fig. 1

Figs. 1-A through 1-D Radiographs of the pelvis and hips of a woman who underwent bilateral VCO. Fig. 1-A Radiograph of the pelvis and hips, made at the age of 40 years, showing advanced-stage osteoarthritis with severe acetabular dysplasia in both hips. Fig. 1-B VCO was performed on the left hip at the age of 40 years. Fig. 1-C VCO was performed on the right hip 1 year later. Fig. 1-D Radiograph showing preserved joint space 24 and 23 years after the operations on the left and right hips, respectively.

Fig. 2

Figs. 2-A, 2-B, and 2-C Radiographs of the right hip of a woman who underwent VCO with autogenous bone-grafting at the age of 30 years. Fig. 2-A Radiograph of the right hip, showing advanced-stage osteoarthritis with severe acetabular dysplasia. Fig. 2-B Radiograph made after VCO, followed by insertion of an autologous iliac-crest bone graft at the acetabular rim. Fig. 2-C Radiograph, made 2 years postoperatively, showing good joint remodeling.

Fig. 3

Figs. 3-A through 3-D Radiographs of the right hip of a woman who underwent VCO for the treatment of an unstable femoral head at the age of 38 years. Fig. 3-A Radiograph showing advanced-stage osteoarthritis with severe acetabular dysplasia. Fig. 3-B Dynamic radiograph showing the femoral head with hinge adduction, which causes the lateral joint space to open wide and the weight-bearing area of the elliptical head to become horizontal. Fig. 3-C Radiograph made after VCO, showing a high pelvic osteotomy angle. Fig. 3-D Radiograph, made 2 years postoperatively, showing good joint remodeling.

Fig. 4

Left image Diagram illustrating the methods used to evaluate preoperative and postoperative radiographic parameters, including the acetabular head index (b/a × 100%) (A), the Sharp angle (in degrees) (B), and the acetabular roof obliquity (in degrees) (C). Right image Diagram illustrating the methods used to evaluate intraoperative radiographic parameters, including the height of pelvic osteotomy (in millimeters) (D), the osteotomy angle (in degrees) (E), and the pelvic displacement ratio (the ratio of displacement distance of the pelvic osteotomy on the anteroposterior view) (d/c × 100%) (F).

Fig. 5

Bar graph showing mean JOA hip scores before and after VCO. The p values pertain to the differences between the postoperative scores and the preoperative score as determined with the Student t test. ADL = activities of daily living, and ROM = range of motion.

Fig. 6

Kaplan-Meier survivorship curves indicating the probability of survival from the time of the operation until the end point of conversion to total hip arthroplasty.