This study reports the 20-year outcomes of the first 75 hips treated with Bernese periacetabular osteotomy (PAO) for symptomatic developmental dysplasia of the hip (DDH). It asks whether the procedure maintains hip preservation at two decades, what clinical and radiographic factors predict failure, and how outcomes compare to natural history.
When you are deciding whether to offer a young patient PAO for DDH, the Tönnis OA grade at presentation is your most important prognostic variable. A grade 0 or 1 hip has a 75% chance of remaining preserved at 20 years. A grade 2 or 3 hip has only a 13% chance — odds that should prompt serious discussion about whether joint preservation is the right goal.
The anterior impingement test deserves attention beyond its routine use. In this cohort it carried a hazard ratio of 6.17 for failure, the highest of any single predictor. A positive test likely reflects labral pathology that mechanical acetabular reorientation alone cannot fully address.
The surgically controllable variable is the postoperative extrusion index. Leaving it above 20% replicates the eccentric loading of dysplasia. But overcorrecting into retroversion substitutes impingement for instability. The technical goal — adequate coverage without retroversion — explains why PAO has a meaningful learning curve.
This series also sets realistic long-term expectations. Even in selected patients operated on early in the procedure's development, 60% of hips were preserved at 20 years. Patients should understand that PAO delays, but does not necessarily prevent, eventual arthroplasty.
This study reports the 20-year outcomes of the first 75 hips treated with Bernese periacetabular osteotomy (PAO) for symptomatic developmental dysplasia of the hip (DDH). It asks whether the procedure maintains hip preservation at two decades, what clinical and radiographic factors predict failure, and how outcomes compare to natural history.
When you are deciding whether to offer a young patient PAO for DDH, the Tönnis OA grade at presentation is your most important prognostic variable. A grade 0 or 1 hip has a 75% chance of remaining preserved at 20 years. A grade 2 or 3 hip has only a 13% chance — odds that should prompt serious discussion about whether joint preservation is the right goal.
The anterior impingement test deserves attention beyond its routine use. In this cohort it carried a hazard ratio of 6.17 for failure, the highest of any single predictor. A positive test likely reflects labral pathology that mechanical acetabular reorientation alone cannot fully address.
The surgically controllable variable is the postoperative extrusion index. Leaving it above 20% replicates the eccentric loading of dysplasia. But overcorrecting into retroversion substitutes impingement for instability. The technical goal — adequate coverage without retroversion — explains why PAO has a meaningful learning curve.
This series also sets realistic long-term expectations. Even in selected patients operated on early in the procedure's development, 60% of hips were preserved at 20 years. Patients should understand that PAO delays, but does not necessarily prevent, eventual arthroplasty.