Atypical Hip Pain in Femoroacetabular Impingement: A Comparison of Outcomes Based on Primary Hip Pain Location

Abstract

Background: Patients with symptomatic femoroacetabular impingement (FAI) typically have anterior groin pain. However, a subset of these patients may have pain located laterally, posteriorly, or in a combination of locations around the hip.

Purpose: To report and compare outcomes of hip arthroscopy for patients with FAI and atypical hip pain versus classic anterior groin pain.

Study design: Cohort study; Level of evidence, 2.

Methods: Consecutive patients undergoing hip arthroscopy for FAI between August 2011 and March 2013 were identified. A total of 258 patients were identified as having symptomatic FAI based on clinical, radiographic, and advanced imaging diagnosis of FAI. Exclusion criteria included isolated thigh, knee, or low back pain. We also excluded patients with hip abductor pathology and trochanteric bursitis. Of the 226 patients ultimately included, 159 (70.4%) reported anterior groin pain, while 67 (29.6%) reported isolated lateral or posterior hip pain or a combination of locations. Patients were categorized into 4 groups: isolated anterior groin pain, lateral hip pain, posterior hip pain, and multiple primary hip pain locations (combined). These patients were followed prospectively with a minimum follow-up of 2 years. Patient characteristics, surgical characteristics, modified Harris Hip Score (mHHS), Non-arthritic Hip Score (NAHS), revision hip arthroscopy, and conversions to total hip arthroplasty (THA) were recorded.

Results: All 226 patients were included at final follow-up. Hip arthroscopy was performed by a single sports medicine fellowship-trained orthopaedic surgeon. Preoperative patient characteristics and baseline functional outcome scores did not significantly differ among groups. All 4 groups showed statistically significant improvements in mHHS and NAHS from baseline to final follow-up of a mean 2.63 years (range, 2.01-3.23 years). Functional outcome scores and rates of revision hip arthroscopy or conversion to THA did not significantly differ between groups.

Conclusion: Hip arthroscopy can effectively improve patient outcomes in atypical hip pain. A careful history and physical examination should identify this clinically meaningful subset of patients with FAI who can benefit from surgical intervention while identifying patients with concomitant posterior extra-articular hip or spine pathology that should be addressed appropriately.

Keywords: anterior groin pain; atypical hip pain; femoroacetabular impingement; hip arthroscopy; posterior hip pain.