Surgical correction of "cam-type" femoroacetabular impingement: a cadaveric comparison of open versus arthroscopic debridement.

PURPOSE: The goal of this study was to compare open and arthroscopic surgical techniques for "cam-type" femoroacetabular impingement in terms of feasibility and reliability.

METHODS: We used 5 fresh-frozen cadaver specimens (10 hips). Anteroposterior and cross-table radiographs were taken for each. The head-neck union diameter was measured for each. The amount of bone resection at the anterolateral quadrant of the head-neck union was planned for each, with specific references to width, length, depth, and position. One side was randomly assigned to the open group and the other to the arthroscopic group. Surgical time, position of the osteotomy, and variation of the length, width, and depth of the final osteotomy with respect to the proposed dimensions were compared.

RESULTS: In all specimens partial resection of the anterior-lateral femoral head-neck junction with improvement of the femoral head-neck offset was accomplished. A statistically significant difference (P < .05) was observed for surgical time between the open and arthroscopic groups (shorter in open group).

CONCLUSIONS: When comparing surgical precision, no statistically significant differences were found between the open and arthroscopic procedures in any of the measurements. The depth and width of the osteoplasty were reliably obtained by the arthroscopic technique. However, there was a tendency to underestimate the osteoplasty length with the arthroscopic procedure. Positioning the osteoplasty was also less reliable with the arthroscopic procedure than with the open procedure because of the tendency to place the osteoplasty more posterior and distally than intended.

CLINICAL RELEVANCE: Surgical resection of the femoral neck prominence and/or part of the anterolateral neck has been reported to improve femoral head offset and alleviate impingement. This study attempts to document the accuracy of this resection when done arthroscopically compared with an open procedure.