The Bernese periacetabular osteotomy (PAO) is controversial as a treatment for symptomatic acetabular dysplasia in patients ≥40 years of age.  We conducted a retrospective study to evaluate the outcomes, measure the survival rate, and identify factors associated with PAO failure in patients ≥40 years of age.


 We performed a retrospective study of patients ≥40 years of age undergoing PAO.  Study eligibility criteria were met by 166 patients (149 women; mean age, 44 ± 3 years), and 145 (87%) were followed for ≥4 years after PAO.  We used simple logistic regression models to determine whether any preoperative characteristics were significantly associated with PAO failure.


 Sixty-one of 145 hips (42%, 95% confidence interval [CI] = 34% to 51%) experienced PAO failure during follow-up.  PAO is usually effective at improving function and is effective at preserving the hip in patients ≥40 years of age provided that they have good preoperative function and no or mild preoperative osteoarthritis (Tönnis grade 0 or 1).  2) and those with poor preoperative dysfunction have a high risk of therapeutic failure after PAO.



PAO
We used a Kaplan-Meier curve with right-censoring to calculate survivorship, with "failure" defined as either conversion to or recommendation for total hip arthroplasty or a Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain score of ≥10 at the most recent follow-up. 
Kaplan-Meier curve
We used simple logistic regression models to determine whether any preoperative characteristics were significantly associated with PAO failure.



logistic regression models
We used a Kaplan-Meier curve with right-censoring to calculate survivorship, with "failure" defined as either conversion to or recommendation for total hip arthroplasty or a Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain score of ≥10 at the most recent follow-up.  Higher preoperative Tönnis arthritis grades (p = 0.03) and worse WOMAC function scores (p < 0.001) were associated with an increased likelihood of failure.



WOMAC
The median survival time was longer for hips with no or mild preoperative osteoarthritis: 17.0 years for Tönnis grade 0, 14.6 years for grade 1, and 12.9 years for grade 2.  PAO is usually effective at improving function and is effective at preserving the hip in patients ≥40 years of age provided that they have good preoperative function and no or mild preoperative osteoarthritis (Tönnis grade 0 or 1).  Patients who are ≥40 years old with advanced preoperative osteoarthritis (Tönnis grade 
Tönnis grade