The invisible hip: radiographic "misses" in hip-spine syndrome and the diagnostic disparity between orthopedic surgeons and neurosurgeons.

PURPOSE: Hip-spine syndrome (HSS) presents a diagnostic challenge because hip and lumbar disorders often cause overlapping symptoms. This study aimed to determine the frequency of radiographically evident hip pathology but clinically undiagnosed prior to spine surgery, and to compare diagnostic patterns between orthopedic surgeons (OS) and neurosurgeons (NS). METHODS: This retrospective cohort study used a multi-institutional medical records database from 2003 to 2018. Patients aged 50-85 years who underwent lumbar spine surgery followed by hip arthroplasty within 1 year were included and stratified by spine surgeon specialty (OS vs. NS). Preoperative kidney-ureter-bladder (KUB) or pelvic radiographs were reviewed for hip osteoarthritis (Kellgren-Lawrence grade ≥ 2), or avascular necrosis (Ficat-Arlet stage ≥ 2). Radiographic underdiagnosis was defined as qualifying hip pathology without a corresponding documented hip-related diagnosis prior to spine surgery. RESULTS: Among 189 patients, OS more frequently obtained preoperative KUB or pelvic radiographs than NS (83.5% vs. 57.6%, p < 0.001). Among patients with available imaging (n = 134), documented hip-related diagnoses were more common in the OS group (42.0% vs. 22.6%, p = 0.021), whereas radiographic underdiagnosis was more common in the NS group (71.7% vs. 48.1%, p = 0.009). Surgeon specialty remained significantly associated with radiographic underdiagnosis after adjustment (adjusted OR 0.384, 95% CI 0.181-0.815, p = 0.013). CONCLUSION: In this selected cohort of patients with hip-spine syndrome, orthopedic surgeons more frequently obtained hip-covering radiographs and documented hip-related diagnoses than neurosurgeons. However radiographic underdiagnosis remained common in both groups. These findings support a more structured evaluation of both hip and spinal pathology before spine surgery.