Lumbosacral Transitional Vertebrae Predict Inferior Patient-Reported Outcomes After Hip Arthroscopy.

ABSTRACT

BACKGROUND: While the association between spinal disease and hip arthroplasty outcomes has been well studied, there is less known about the effect of spinal pathology in hip arthroscopy (HA) outcomes. Lumbosacral transitional vertebrae (LSTV) are anatomic variations where caudal vertebrae articulate or fuse with the sacrum or ilium. HYPOTHESIS: LSTV can lead to inferior outcomes after HA for treatment of femoroacetabular impingement. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: We retrospectively reviewed the prospectively collected Hip Arthroscopy Database at our institution for patients with LSTV who underwent HA between 2010 and 2017. A total of 62 patients with LSTV were identified and then matched to controls. Patient-reported outcome measures (PROMs) were collected, including the modified Harris Hip Score, Hip Outcome Score-Activities of Daily Living, Hip Outcome Score-Sports, and the 33-item International Hip Outcome Tool. They were collected at 4 time points preoperatively and 5 to 11 months, 12 to 23 months, and 24 to 35 months postoperatively. Longitudinal analysis of the PROMs was done using generalized estimating equation modeling. Additionally, alpha angles were measured from preoperative radiographic data. RESULTS: Preoperatively, there was no significant difference between patients with and without LSTV on 3 of the 4 PROMs; however, patients with LSTV did have significantly lower preoperative scores than controls for the Hip Outcome Score-Activities of Daily Living (P = .029). Patients with LSTV reported significantly lower scores on all 4 PROMs at each postoperative time point. Radiographic data showed no significant difference in alpha angles across cohorts. When LSTV were compared by Castellvi type, types 3 and 4 tended to have lower scores than types 1 and 2; however, these comparisons were not significant. CONCLUSION: The data support our hypothesis that HA has less benefit in patients with LSTV as compared with patients without LSTV. In patients with LSTV, careful evaluation of the anomaly is recommended to help guide surgical counseling and manage expectations.