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.