Dysplastic Hips That Are Too Late For Periacetabular Osteotomy Are Not Too Early For Total Hip Arthroplasty.

INTRODUCTION: Total hip arthroplasty (THA) is often performed in symptomatic patients who have hip dysplasia and do not qualify for periacetabular osteotomy (PAO). The impact of osteoarthritis (OA) severity on postoperative outcomes in dysplasia patients who undergo THA is not well described. We hypothesized that dysplasia patients who have mild OA have slower initial recovery postoperatively, but similar one-year patient-reported outcome measures (PROMs) compared to dysplasia patients who have severe OA.

METHODS: We performed a retrospective review at a single academic institution over a six-year period of patients who have dysplasia who underwent THA compared to patients who have primary OA who underwent THA. There were 263 patients who had dysplasia were compared to 1,225 THA patients who did not have dysplasia. Within the dysplasia cohort, we compared PROMs stratified by dysplasia and OA severity. The diagnosis of dysplasia was verified using the radiographic lateral center edge angle (LCEA). A minimum one-year follow-up was required. The PROMs were collected through one year postoperatively. Logistic and linear regression models were used, adjusting for age, sex, body mass index, and Charlson comorbidity index.

RESULTS: No significant differences were found in postoperative PROMs or revision rates (P = 0.58). When stratified by dysplasia severity, patients who had lower LCEA had more improvement in physical function scores from pre-operative to 2-weeks (P < 0.01) and higher physical function scores at 2-weeks (P = 0.03). When stratified by OA severity, patients who had a worse Tönnis score had more improvement in physical function scores from pre-operative to 2 weeks (P < 0.01). Recovery curves in dysplasia patients based on dysplasia and OA severity were not significantly different at 6-weeks, 1-year, and 2-years post-operative.

CONCLUSION: Patients who had hip dysplasia and mild OA had similar recovery curves compared to those who had severe OA or who did not have dysplasia. We believe that THA is a reasonable surgical intervention for symptomatic dysplasia patients who have mild arthritis and do not qualify for PAO.