Predictive radiological parameters of failure following surgical management of femoroacetabular impingement associated with borderline acetabular dysplasia.

INTRODUCTION: The role of arthroscopic treatment of femoroacetabular impingement (FAI) in mild or borderline hip dysplasia (lateral center edge angle=18-25) is controversial. It is recommended to combine capsular plication with femoral neck osteoplasty and suture repair of the labrum. Few studies have investigated which radiological parameters are associated with failure of this procedure. HYPOTHESIS: A larger number of radiological signs of mild or borderline hip dysplasia than radiological signs of FAI negatively influence the outcomes of arthroscopic treatment. METHODS: This was a retrospective study done with data collected prospectively after a minimum of 2 years' follow-up in patients who underwent arthroscopic treatment of FAI due to cam impingement combined with mild to moderate hip dysplasia. Patients with hip osteoarthritis graded as ≥ Tönnis 2 were excluded. Functional outcome scores (mHHS and NAHS) were determined along with the need for reoperation. Three groups were defined based on the outcomes: success (mHHS ≥ Patient Acceptable Symptomatic State [PASS]); moderate improvement (improvement in mHHS + mHHS