The current study aimed to determine the influence of acetabular coverage and intraarticular pathology on post-operative functional outcomes of arthroscopy for cam type FAI.

Based on 762 hip scopes performed by a single surgeon between 2013 and 2016, we excluded patients with previous surgery on the hip, mixed FAI, surgical hip dislocation, and missing outcome scores. From this, 97 hips between the ages 17 and 48 that underwent arthroscopy for cam deformity were identified for analysis. Every patient received a partial capsulotomy, cam resection and either labral repair or resection. Measurements for acetabular coverage consisted of pre-operative lateral edge angle (LCEA) (mean 30°, range: 15.4°–40°) and three-dimensional anterior and posterior acetabular coverages. Intraoperative Beck scores were acquired from operative reports, and Hip Disability and Osteoarthritis Outcome Score (HOOS) was collected pre- and post-operatively.

Significant post-operative improvement was found in scores of all categories of the HOOS (p < 0.05). However, improvement in HOOS was not correlated with the LCEA, anterior coverage, or posterior coverage. There was a trend toward lower Beck grades (1–3) resulting in better HOOS outcomes than higher Beck grades (4–5). Also, lower Beck grades showed significantly lower alpha angle (mean = 55.86) than higher grades (mean = 73.48).

We showed that cam FAI arthroscopic resection improved patient outcome, and confirmed the relationship between the Beck score and functional outcome. However, functional improvement was not related to acetabular coverage suggesting that the so-called “borderline” dysplasia is not a useful radiographic indicator for surgical management.