The hip-shelf procedure is less often indicated since the introduction of peri-acetabular osteotomy (PAO). Although this procedure does not modify pelvic shape, its influence on subsequent total hip arthroplasty (THA) is not known. We performed a case-control study comparing THA after hip-shelf surgery and THA in dysplastic hips to determine: 1) its influence on THA survival, 2) technical issues and complications related to the former procedure.

We performed a retrospective case-control study comparing 61 THA cases done after hip-shelf versus 63 THA in case-matched dysplastic hips (control group). The control group was matched according to sex, age, BMI, ASA and Charnley score, and bearing type. We compared survival and function (Harris, Oxford-12), complications at surgery, rate of bone graft at cup insertion, and post-operative complications.

The 13-year survival rates for any reason did not differ: 89% ± 3.2% in THA after hip shelf versus 83% ± 4.5% in the controls (p = 0.56). Functional scores were better in the control group (Harris 90 ± 10, Oxford 41/48) than in the hip-shelf group (Harris 84.7 ± 14.7, Oxford 39/48) (p = 0.01 and p = 0.04). Operative time, bleeding and rate of acetabular bone grafting (1.6 hip-shelf versus 9.5 control) were not different (p > 0.05). Postoperative complication rates did not differ: one transient fibular nerve palsy and two dislocations (3.2%) in the hip-shelf group versus four dislocations in the control group (6.3%).

The hip-shelf procedure does not compromise the results of a subsequent THA in dysplastic hips. This procedure is simple and may keep its indications versus PAO in severely subluxed hips or in case of severe femoral head deformity.