The anatomical properties of the indirect head of the rectus femoris tendon: a cadaveric study with clinical significance for labral reconstruction surgery.

BACKGROUND: Acetabular labral tear is a common pathology. In some clinical situations, primary labral repair may not be possible and labral reconstruction is indicated. PURPOSE AND CLINICAL RELEVANCE: Describe the anatomy of the indirect head of the rectus femoris (IHRF) tendon with clinical application in arthroscopic labral reconstruction surgery. METHODS: Twenty-six cadaver hips were dissected. Thirteen measurements, each with clinical relevance to arthroscopic labral reconstruction using an IHRF tendon graft were taken on each hip. All measurements were taken in triplicate. Mean values, standard deviations and intra-observer reliability were calculated. RESULTS: The mean footprint of the direct head of the rectus femoris tendon was 10.6 mm × 19.6 mm. The width and thickness at the confluence of both heads were 10.9 mm and 6.9 mm, respectively. The mean total length of the footprint and "free portion" of the IHRF was 55.3 mm, the mean cranial to caudal footprint measured at the 12 o'clock, 1 o'clock, and 2 o'clock positions were 22.3 mm. The mean length of the Indirect Head footprint alone was 38.1 mm. The mean length of IHRF tendon suitable for grafting was 46.1 mm and the mean number of clock face sectors covered by this graft was 3.3 clock face sectors. Intra-observer reliability was ≥ 0.90 for all recorded measurements. The origin of the IHRF on the acetabulum fans out posteriorly, becoming thinner and wider as the origin travels posteriorly. The tendon footprint is firmly attached on the lateral wall of the ilium and becomes a free tendon overlying the acetabular bone as it travels anteriorly and distally towards its muscular attachment. CONCLUSION: The IHRF tendon is in an ideal location for harvesting and contains the appropriate thickness, length and triangular architecture to serve as a safe and local graft source for acetabular labral reconstruction surgery.