Patients with Lateral and Anterolateral Cam Morphology Have Greater Deformities Versus Typical Anterolateral Deformity Alone, but No Differences in Postoperative Outcomes: A Propensity-Matched Analysis at Minimum 5-Year Follow-Up.

PURPOSE: To compare pre- and post-operative findings between patients undergoing hip arthroscopy for femoroacetabular impingement syndrome (FAIS) with lateral impingement versus those without lateral impingement METHODS: Patients who underwent primary hip arthroscopy for FAIS between 2012-2017 with minimum 5-year follow-up were included. Alpha angle (AA) was measured on preoperative AP and 90° Dunn radiographs. Patients with AA > 60° on Dunn view but not AP view (no lateral impingement) were propensity matched by sex, age, and BMI in a 1:3 ratio to patients with AA > 60° on both views (lateral impingement). Demographic characteristics, radiographic and intraoperative findings, reoperation rates, and patient-reported outcomes (PROs) were compared between groups. Categorical variables were compared us Fisher's exact testing and continuous variable using two-tailed student's t tests.

RESULTS: Sixty patients with lateral impingement (65.0% female, age: 35.3 ± 13.0 years) were matched to 180 patients without lateral impingement (65.0% female, age: 34.7 ± 12.5 years, p ≥ 0.279). Lateral impingement patients had larger preoperative AAs on both Dunn (71.0° ± 8.8° vs. 67.6° ± 6.1°, p = 0.001) and AP radiographs (79.0° ± 12.1° vs. 48.2° ± 6.5°, p < 0.001). However, there were no differences in postoperative AAs on either view (Dunn: 39.0° ± 6.1° vs. 40.5° ± 5.3°, AP: 45.8° ± 9.0° vs. 44.9° ± 7.0°, p ≥ 0.074). Labral tears began more superiorly in patients with lateral impingement (12:00 ± 0:49 vs. 12:17 ± 0:41, p = 0.030), and theydemonstrated higher rates of acetabular and femoral cartilage damage (p = 0.030 for both); however, there were no differences in PROs or reoperation rates between the groups at 5-year follow-up.

CONCLUSIONS: Although cam deformities located laterally and anterolaterally are larger than those located anterolaterally alone, both can be resected adequately, resulting in similar postoperative radiographic measurements, PROs, and survivorship.