Mid-term outcomes of modified colonna capsular arthroplasty in adolescent and young adult patient with unilateral hip dysplasia dislocation.

BACKGROUND: Hip preservation remains a significant surgical challenge in adolescent and young adult patient with unilateral developmental dysplasia of hip (DDH). We compared the clinical and radiographic results of modified Colonna capsular arthroplasty in unilateral DDH patients. METHODS: The records of 19 consecutive patients (19 hips) who underwent modified Colonna capsular arthroplasty between 2017 and 2019 were retrospectively reviewed. There were 3 males and 16 females, with a mean age of 19.1 years at the time of surgery. We used the modified Harris Hip Score (mHHS), Visual analogue scale (VAS) scores and limb-length discrepancy (LLD) to evaluate the clinical outcomes. X-ray was used to measure the femoral anteversion angle, lateral center-edge angle and acetabular coverage. RESULTS: The median follow-up time was 70.7 months. The average operative time and intraoperative blood loss were 80.5 ± 5.0 (range 75 to 95) minutes and 189.7 ± 15.3 (range 165 to 210) mL, respectively. The average mHHS improved from 58.6 ± 3.6 (range 50.5 to 62.5) preoperatively to 86.9 ± 2.1 (range 82.5 to 90.5) at the final follow-up (p < 0.05). The mean femoral anteversion angle had decreased from 40.8° ± 2.4° (range 36.5° to 44.6°) preoperatively to 15.2° ± 1.8° (range 12.2° to 18.8°) at the final follow-up with a statistically significant difference (p < 0.05). The average LLD decreased significantly from 28.3 ± 4.6 mm preoperatively to 10.8 ± 2.4 mm at the final follow-up, respectively. One patient was converted to total hip arthroplasty at 6 years postoperatively. However, there was no significant difference in VAS between preoperative and the final follow-up. According to the curative effect evaluation standard score of DDH, the excellent and good rate was 73.7%. Furthermore, the lateral center-edge angle and the acetabular coverage showed significant improvement in all hips after operation. CONCLUSIONS: The modified Colonna capsular arthroplasty demonstrates favorable mid-term outcomes for adolescent and young adult patients with unilateral DDH. This procedure effectively improves hip function and radiographic parameters. Nevertheless, further studies with longer follow-up are need to determine the long-term efficacy.