Summary

This study presents the results of our algorithm for diagnosis and management of patients with FAI and concomitant Os Acetabuli Lesions treated with hip arthroscopy.

Abstract

Purpose

An Os Acetabuli is a lesion of the acetabular rim often encounter in patients with hip dysplasia and Femoral Acetabular Impingement (FAI). While such lesions have been identified as a potential cause of intra-articular hip pain, the optimal management of an Os in the setting of symptomatic FAI remains unclear. We present our approach to management of such concomitant pathology in a series of 20 patients treated with hip arthroscopy.

Methods

As part of an initial workup, plain films of the hip along with a Three-Dimensional CT and MRI were obtained. In addition to calculation of pre-intervention alpha and center edge angles, individual Os lesions were identified arthroscopically and managed via an algorithm based on four distinct anatomic locations. All patients underwent a predetermined treatment algorithm for FAI and the identified Os lesions. Pre and post-surgery outcomes were collected in the form of a Harris Hip Scoring along with ADL and Sports Hip Outcome Score subsets.

Results

Outcome data was successfully collected in 20 patients with a mean age of 35.04 (range 20-51) years. When compared to plain films (68.7%) and MRI (31.3%), three-dimensional CT represented by far the most sensitive method of pre-intervention screening, detecting 100% of Os lesions eventually confirmed during arthroscopy (p<0.001). Following treatment at a mean follow-up of 40.33 (range 22-62) months, average Harris Hip Scores improved by 22.66 points (p=.037) from baseline. Hip Outcome Scores increased by an average 15.98 points for ADL and 24.99 points for sports (p=0.023) subsets, respectively.

Conclusions

Symptomatic FAI with concomitant a Os acetabuli lesion can be successfully managed arthroscopically via a treatment algorithm based on anatomic location. Due to its increased sensitivity in detecting Os lesions compared to other imaging modalities, a three-Dimensional CT scan should be considered prior to surgical intervention.