The goal of periacetabular osteotomy (PAO) is to delay or prevent osteoarthritic development in dysplastic hips. However, it is unclear whether the surgical goals are achieved and if so in which patients. This information is essential to select appropriate patients for a durable PAO that achieves its goals.

We therefore (1) determined hip survival rates; (2) determined how many preserved hips were functionally successful after PAO; and (3) identified demographic, clinical, and radiographic factors predicting failure after PAO.

We reviewed 316 patients (401 hips) who had PAO. We evaluated radiographic parameters and obtained WOMAC scores. Through inquiry to the National Registry of Patients, we identified conversions to THA. Risk factors for conversion to THA were assessed. Mean followup was 8 years (range, 4–12 years).

We conclude that PAO can be performed with a good outcome at medium to long term follow-up, suggesting that it may be applied by experienced surgeons with satisfactory results. To further improve the outcome, focus should be on the potential negative influence of parameters that are easily assessed, such as the patients age (>45) preoperative grade of osteoarthritis, incongruency, and severe acetabular dysplasia. Perioperatively, the surgeon should attempt to achieve hip congruence and a CE angle between 30° to 40° to improve the durability of PAO.

Level II, prognostic study.

Objectives

The accuracy and precision of two new methods of model-based radiostereometric analysis (RSA) were hypothesised to be superior to a plain radiograph method in the assessment of polyethylene (PE) wear.