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

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

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This study investigates the impact of proximal over-resection during femoral osteochondroplasty on the stability of the hip joint, specifically focusing on its effect on the suction seal mechanism and distractive stability. The hip’s suction seal, formed by the contact between the acetabular labrum and the femoral head cartilage, is crucial for maintaining intra-articular fluid pressurization and femoral head stability. Over-resection during surgery, particularly proximal extension into the femoral head, may compromise this seal.<br /><br />Using six cadaveric hemi-pelvic specimens, the researchers performed controlled osteochondroplasty resections with varying degrees of proximal extension. They measured hip joint distractive stability (axial distraction forces of 0-150N at flexion angles 0° to 90°) and rotational stability (internal/external torque of 5Nm). Displacement and rotation were tracked with 3D motion analysis, and statistical comparisons were made to intact and capsulotomy states.<br /><br />Results indicated that proximal over-resection, especially at 5 mm and 10 mm extensions, significantly increased femoral head distraction compared to intact hips, demonstrating reduced distractive stability. This effect was evident across multiple flexion angles and distraction forces. Rotational stability showed minimal changes except for increased external rotation at extreme over-resection (10 mm) with high hip flexion (90°). The findings suggest that proximal over-resection diminishes the articular surface available for the suction seal, leading to compromised hip distractive stability.<br /><br />Limitations include the cadaveric model without dynamic stabilizers, non-physiologic conditions, and open surgical approach. Despite these, the study emphasizes the critical need for precise femoral osteochondroplasty to avoid proximal over-resection that risks iatrogenic hip instability and poorer clinical outcomes. Accurate resection preserves hip joint stability by maintaining the suction seal integrity vital for postoperative success.

Keywords

proximal over-resection

femoral osteochondroplasty

hip joint stability

suction seal

acetabular labrum

femoral head cartilage

distractive stability

rotational stability

cadaveric study

iatrogenic hip instability