Risk of Conversion to Total Hip Arthroplasty Following Periacetabular Osteotomy (PAO) for Hip Dysplasia
Logistic regression–based risk estimation at 5 and 10 years (research tool; not a validated clinical decision aid).

Inputs

Continuous predictor in both models.
Used to calculate BMI.
Used to calculate BMI.
BMI is computed automatically from height and weight, or can be entered directly.
Obesity (BMI ≥ 30): —
Used only in the 5-year model.

Results

Risk of THA ≤ 5 years

—

Not calculated
Model (5y): logit(p) = β0 + βAge·Age + βTönnis·Tönnis + βAI13·(AI≥13)

Risk of THA ≤ 10 years

—

Not calculated
Model (10y): logit(p) = β0 + βAge·Age + βTönnis·Tönnis + βObesity·(BMI≥30)
Obesity is defined as BMI ≥ 30 kg/m². This risk calculation is based on research data from the Department of Orthopaedic Surgery at Inselspital, Bern, Switzerland, including long-term follow-up of patients treated with periacetabular osteotomy (PAO) for hip dysplasia. PAO was originally developed at this institution in 1984. Consequently, the underlying dataset includes heterogeneous cases spanning the early learning curve as well as contemporary surgical techniques, and represents one of the longest available follow-up periods worldwide. This model is only applicable to patients with developmental hip dysplasia treated with PAO. Risk estimation is not valid for other hip pathologies such as acetabular retroversion. No warranty is given regarding the accuracy, completeness, or applicability of the calculated results. The authors and the hosting institution accept no liability for clinical decisions, treatments, or outcomes based on the use of this tool. This page does not store or transmit data (runs locally in your browser).