OBJECTIVETo discuss the early clinical results and risk factors of modified Colonna capsular arthroplasty for young patients with unilateral hip dislocation.

METHODSFrom July 2011 to February 2013, 25 cases (25 hips) of modified Colonna capsular arthroplasty for unilateral hip dislocation in the 1st affiliated hospital of People's Liberation Army General hospital was collected, including 7 males, 18 females; aged 9.7-25.8 years, averaging 17.8 years; left 12 cases, right 13 cases; Body mass index ranged 15.6-29.6 kg/m², averaging 20.9 kg/m². Clinical indexes were collected, including: range of motion (ROM) of the hip, the Harris Hip Score (HHS), West Ontario and McMaster University Osteoarthritis Index (WOMAC), visual analogue scale (VAS) score before and after surgery, along with the satisfaction score of the surgery, Severin grades, and Tönnis osteoarthritis grades at last follow-up. Paired t-test was applied for the indexes before and after surgery, variances components analysis was applied for the satisfaction score and the function scores at last follow-up compared in 2 groups, aging at surgery <16 years (15 cases) and ≥ 16 years (10 cases).

RESULTSAll cases were followed up for 12-18 months, mean 13.4 months. The average hip ROM decreased from 380° in average pre-surgery to 200° in average at last follow-up. Indexes decreased comparing 9 months follow-up to pre-surgery, HHS(78 ± 9 vs. 84 ± 15, t = 2.107, P = 0.046), WOMAC function score(14.8 ± 8.4 vs. 8.6 ± 9.6, t = -2.657, P = 0.014) appeared statistically difference. Indexes increased at the last follow-up, showing no statistically difference. VAS and the satisfaction score were much better in patients <16 years group compared with ≥ 16 years group at last follow-up. VAS was 1.1 ± 0.8 compared with 2.8 ± 1.4 (F = 12.810, P = 0.002), whereas the satisfaction score was 89 ± 17 compared with 66 ± 22 (F = 7.535, P = 0.012). The last radiological follow-up resulted that, Severin grade I 21 cases, grade II 1 case, grade III 2 cases, grade IV 2 cases, and the Tönnis osteoarthritis grade 0 with 5 cases, grade 1 with 12 cases, grade 2 with 7 cases, grade 3 with 1 case.

CONCLUSIONSIn this early follow up, the majority of patients who underwent modified Colonna capsular arthroplasty for their unilateral hip dislocation would obtained satisfactory results, but with long term recovery, and the younger group (<16 years) with better clinical results than the elder group ( ≥ 16 years).With strict indications, exacted surgical techniques and optimized rehabilitation, the modified Colonna arthroplasty would have better clinical results.