The purpose of this study was to determine the complications after Bernese periacetabular osteomy (PAO) performed by one experienced surgeon using a minimally invasive modified Smith-Petersen approach.

Between May 2012 and December 2015, 224 periacetabular osteotomies (PAO) in 201 patients were performed. The perioperative complications were retrospectively reviewed after reviewing clinical notes and radiographs. The mean age was 28.8 years with 179 females and 22 males. The most common diagnosis was acetabular dysplasia with some cases of retroversion. The average lateral centre edge (LCE) angle was 16.5°(−18–45) and mean acetabular index (AI) 16.79° (−3–50).

Postoperatively the mean LCE angle was 33.1°(20–51.3) and mean AI 3.0°

(−13.5–16.6). There were no deep infections, no major nerve or vascular injuries and only one allogenic blood transfusion.

Nine superficial wound infections required oral antibiotics and two wounds needed a surgical debridement. There was one pulmonary embolus and one deep vein thrombosis. Nine (4%) cases underwent a subsequent hip arthroscopy and three (1.3%) PAO's were converted to a total hip arthroplasty after a mean follow-up of 22 months (3–50).

Lateral femoral cutaneous nerve dysaesthesia was noted in 64 (28.6%) PAO's. In 55 (24.5%) an iliopsoas injection of local anaesthetic and steroid for persistent iliopsoas irritation during the recovery phase was given.

The minimally invasive modified Smith-Petersen approach is suitable to perform a Bernese periacetabular osteotomy with a low perioperative complication rate. Persistent pain related to iliopsoas is a not uncommon finding and perhaps under-reported in the literature.