AOSSM/AANA Specialty Day 2020-Handout - Proximal Over-Resection During Femoral Osteochondroplasty Negatively Affects the Distractive Stability of the Hip Joint

Handout - Proximal Over-Resection During Femoral Osteochondroplasty Negatively Affects the Distractive Stability of the Hip Joint

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This study investigated the impact of proximal over-resection during femoral osteochondroplasty on the rotational and distractive stability of the hip joint. Hip micro-instability, linked to pain and disability, is influenced by the suction seal formed by the acetabular labrum and femoral head cartilage, which maintains joint stability and protects cartilage integrity. Osteochondroplasty aims to reshape the femoral head to relieve impingement but risks over-resection extending proximally into the femoral head, potentially compromising this seal.<br /><br />Six fresh-frozen hemi-pelvis specimens underwent biomechanical testing at various flexion angles (0°, 15°, 30°, 60°, 90°). Conditions tested included intact state, capsulotomy, and osteochondroplasty at the physeal scar, with 5 mm and 10 mm proximal extensions. Using a multi-axial hip jig and 3D motion tracking, researchers measured rotational stability (internal/external rotation under 5Nm torque) and distractive stability (axial distraction forces from 0–150N).<br /><br />Findings showed that capsulotomy increased external rotational instability at low flexion angles, but osteochondroplasty generally did not exacerbate this, except for a 10 mm proximal extension at 90° flexion. Regarding distractive stability, extended proximal resection caused significantly more distraction compared to the intact state at both low (50 N) and higher distraction forces. Notably, all proximal extensions produced marked instability at higher flexion angles and forces.<br /><br />The study concludes that proximal over-resection during femoral osteochondroplasty substantially compromises hip joint distractive stability, potentially leading to iatrogenic instability and poorer postoperative outcomes. These results underscore the critical importance of precise surgical technique and caution to avoid extending resection proximally beyond the femoral head articular surface. Accurate control may preserve the natural suction seal and maintain hip joint stability post-surgery.

Keywords

proximal over-resection

femoral osteochondroplasty

hip joint stability

rotational stability

distractive stability

acetabular labrum suction seal

hip micro-instability

capsulotomy effects

physeal scar resection

postoperative hip outcomes