Lateral center-edge angle in femoroacetabular impingement: from the sourcil or the rim of the acetabulum?

The correlation between clinical outcomes and preoperative/postoperative measures of the lateral center-edge angle (LCEA) will help establish the cutoff values for this measurement and determine whether to obtain it from the lateral acetabular rim (LCEAR) or the lateral end of the sourcil (LCEAS). The hypothesis was that the LCEAS would be more sensitive than the LCEAR. An upper cutoff value of LCEA could predict better functional outcomes in FAI patients. 106 patients (103 unilateral, 3 bilateral) who underwent hip arthroscopy surgery due to FAI and had a minimum 2-year follow-up were included. Patient-reported outcomes included the mHHS and visual analogue scale for pain (Pain VAS). Radiological parameters (alpha angle, LCEAS, LCEAR) were evaluated at the pelvis, 45° Dunn X-rays. A receiver operating characteristic analysis was used to evaluate the correlation between significant variables and achievement of patient-acceptable symptomatic state (PASS) and calculate area under the curve (AUC) and critical values for LCEA. The mean age of the patients was 34 ±10 years with a mean follow-up of 5 years. There were 75 male and 31 female patients. The mHHS improved from 57 ± 11 before surgery to 93 ± 8 after surgery (P < .001). The Pain VAS decreased from 6 before surgery to 1 after surgery (P < .001). A higher frequency of reaching the PASS threshold for mHHS was associated with lower preoperative and postoperative dunn LCEAS and postoperative dunn LCEAR. Preoperative dunn LCEAS ≤ 24.8° had an AUC of 0.67, predicting PASS (+) with 0.38 sensitivity and 0.93 specificity. Combining LCEAS with other parameters further improved predictability. LCEAS seems more predictive of clinical significance than LCEAR. However, predictivity exceeds the acceptable limit when they are measured together. The upper values for LCEAS and LCEAR seem to be 24° and 35°, respectively.