Editorial Commentary: Spine Pathology May Improve or Worsen Outcomes After Hip Arthroscopy: Patient Evaluation and Indications Are Critical.

Compared with total hip arthroplasty, hip arthroscopy is a relatively new procedure, and as such, hip-spine syndrome in young adults is an emerging topic of research. In the past decade, our understanding of spinopelvic alignment has improved the stability and survivorship of hip replacements in patients with prior lumbar fusions. Obviously, the hip affects the spine and the spine affects the hip. In terms of hip arthroscopy, just as older patients and patients with cartilage damage have inferior outcomes, patients with spine pathology are at risk for postoperative worsening spinal symptoms, including sciatica. In addition, back and radicular pain may limit postoperative hip rehabilitation. Yet other patients show resolution of back symptoms after hip arthroscopy. Today, surgeons indicating hip arthroscopy must first investigate patient sagittal balance, which includes pelvis tilt, pelvic incidence, and sacral slope. When properly indicated, hip-spine pain patients show greater percentage improvement with no increased failure risk compared with patients with isolated FAIS. Exceptions include patients with concomitant lumbar stenosis or lumbar fusion. Rate of revision hip arthroscopy and conversion to total hip replacement is 2-fold compared with controls if patients had prior 1-2 level fusion and 3-fold if 3 or more levels are fused. Our understanding of hip-spine patients with regard to arthroscopy outcomes continues to develop. In addition to a comprehensive spine exam, the patient's spine surgical history and current spine symptoms must be investigated to predict the efficacy of hip arthroscopy. If patients have both hip and spine symptoms, a diagnostic hip injection to determine the prime pain generator is essential. If the hip is the source of pain, patients should be counseled that back symptoms will likely improve after hip arthroscopy but not in all cases. EOS imaging to measure sagittal balance may allow the surgeon to predict if impingement measurements on hip radiographs may be underestimated in the setting of a stiff spine. If the patient has multiple risk factors for poor outcomes such as advancing age, articular cartilage damage, borderline dysplasia, or hypermobility, on top of a history of multilevel lumbar fusion or spinal deformity, hip arthroscopy may not be ideal, and hip arthroplasty should be considered. Clearly, the spine may not be ignored in patients with femoroacetabular impingement.