Evaluation of the Sclerotic Subchondral Bone Boundary as a Surgical Resection Guide in the Treatment of Cam-type Femoroacetabular Impingement

INTRODUCTION: Improper resection depth in the surgical correction of cam-type femoroacetabular impingement (FAI) has been identified as the most common reason for revision hip arthroscopy [1]. Under-resection fails to address patient symptoms and results in the need for revision arthroscopy [1], while over-resection may lead to iatrogenic femoral neck fracture, loss of the normal joint suction seal, or loss of congruency [2-4]. In our experience, removal of the sclerotic subchondral bone within the region of the cam lesion provides a simple method to guide the depth of resection (Figure 1), but quantitative data to demonstrate the suitability of this boundary does not exist. Using threedimensional (3D) computed tomography (CT) reconstructions and statistical shape modeling (SSM), we determined whether removal of subchondral bone alone in the region of the cam lesion in FAI patients could produce femoral anatomy that was not significantly different than normal controls.