Prevalence of Lumbosacral Transitional Vertebrae in Patients With Symptomatic Femoroacetabular Impingement Requiring Hip Arthroscopy

Purpose: The primary aim of this study was to determine the prevalence of lumbosacral transitional vertebrae (LSTVs) in patients with symptomatic femoroacetabular impingement (FAI) requiring hip arthroscopy. The secondary aim was to determine whether there is an association between LSTV anatomy and patient-reported outcomes. Methods: This retrospective study included patients aged 18 to 45 years with symptomatic FAI who underwent arthroscopy between March 2010 and March 2016 and had anteroposterior pelvic radiographs. The exclusion criteria included lack of an FAI diagnosis, hip osteoarthritis (Tonnis grade >= 2), prior spinal fusion surgery, prior total hip arthroplasty, indications for total hip arthroplasty, and revision surgery on the affected hip. All radiographs were assessed by an interventional spine and sports fellow. The primary outcome was the prevalence of LSTVs, classified using the criteria of Castellvi et al. Secondary outcomes included the modified Harris Hip Score, Hip Outcome Score, and International Hip Outcome Tool 33 score. Results: A total of 1,880 patients were included. Review of the patients' radiographs yielded 262 LSTVs, for an overall prevalence of 13.9% (type IA in 104 [5.5%], type IB in 53 [2.8%], type IIA in 60 [3.2%], type IIB in 25 [1.3%], type IIIA in 8 [0.4%], type IIIB in 0 [0%], and type IV in 12 [0.64%]). The prevalence of type II, III, and IV LSTVs was 5.6% (n = 105). Unilateral LSTV sidedness did not correlate with symptom laterality (kappa = 0.07). There were no differences in patient-reported outcomes between patients with LSTV anatomy and those without it. Conclusions: In this large cohort of 1,880 patients with symptomatic FAI, the prevalence of LSTVs was 13.9%. There was no correlation between sidedness of unilateral LSTVs and the symptomatic hip. Furthermore, there was no association between LSTV anatomy and patient-reported outcomes. The prevalence of LSTVs in this cohort was similar to the prevalence rates previously reported in patients with low-back pain.