Long-standing symptoms and high femoral antetorsion predicted a less satisfying periacetabular osteotomy

Design

Retrospective single-surgeon cohort (level III)

Population

133 patients (mean age 24, 94% women) after Bernese periacetabular osteotomy

Primary outcome

Achievement of MCID, PASS and SCB on HOOS and iHOT-12 at ≥1 year

Effect

PASS 77%, SCB 70%; symptoms >2 years OR 0.3 (0.1–0.9) for PASS; antetorsion >25° OR 0.2 (0.1–0.9)

Raw outcome scores do not tell a surgeon whether a patient's improvement is worth having. This single-surgeon series of 133 Bernese periacetabular osteotomies (mean age 24, 94% women; two-thirds with staged hip arthroscopy) set procedure-specific thresholds for three benchmarks: the minimal clinically important difference (MCID), the patient acceptable symptom state (PASS) and substantial clinical benefit (SCB).

Thresholds for HOOS and iHOT-12 were defined — for iHOT-12, 16, 75 and 77 points respectively. Overall, 83% reached the MCID on at least one measure, 77% a PASS and 70% SCB, so roughly one in four did not reach an acceptable symptom state. Symptoms for more than two years were associated with lower odds of PASS (OR 0.3, 95% CI 0.1 to 0.9) and SCB (OR 0.4, 0.2 to 0.9), and femoral antetorsion above 25° with lower odds of PASS (OR 0.2, 0.1 to 0.9).

The practical message is about timing and anatomy. Hip dysplasia in young adults is often labelled as mechanical back or groin pain for years; this suggests delay may cost outcome. And a high femoral version may need its own attention.

• Measure femoral version (CT or MRI) before periacetabular osteotomy; antetorsion above 25° was linked to worse results.
• Tell patients with symptoms longer than two years that the chance of a satisfying result is lower.
• Refer young adults with groin pain and a dysplastic acetabulum on plain film early rather than after years of conservative care.
• Use PASS and SCB thresholds, not raw score change, when auditing your own hip-preservation outcomes.
• Counsel that roughly one in four patients did not reach an acceptable symptom state.

Why it matters

Years of symptoms before referral may be part of why a quarter of patients are not satisfied with a technically successful osteotomy.

Don't overread it

One surgeon's series with wide confidence intervals; the thresholds need validation before being used as standards.

The statistics, in plain English

MCID is the smallest change a patient notices; PASS is the score at which they consider their state acceptable; SCB is a change they consider substantial. The odds ratios have wide intervals because the numbers are small, so the direction is more reliable than the size.

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