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 (LCEA R ) or the lateral end of the sourcil (LCEA S ). The hypothesis was that the LCEA S would be more sensitive than the LCEA R . 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, LCEA S , LCEA R ) 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 LCEA S and postoperative dunn LCEA R. Preoperative dunn LCEA S ≤ 24.8° had an AUC of 0.67, predicting PASS (+) with 0.38 sensitivity and 0.93 specificity. Combining LCEA S with other parameters further improved predictability. LCEA S seems more predictive of clinical significance than LCEA R . However, predictivity exceeds the acceptable limit when they are measured together. The upper values for LCEA S and LCEA R seem to be 24° and 35°, respectively.