Patients Requiring Both Total Hip Arthroplasty and Lumbar Spinal Fusion Have Lower Hip Functional Outcome Scores: A Matched Case-Control Study

Background: While patients who undergo both lumbar spinal fusion (LSF) and total hip arthroplasty (THA) have increased complication rates compared to patients who have not undergone LSF, there is a paucity of literature evaluating THA functional outcomes in patients with a history of LSF. This study was conducted to determine whether patients undergoing THA with a history of LSF have inferior functional outcomes compared to patients having no history of LSF. Methods: A retrospective matched case -control study was conducted at an academic center. Patients who underwent both THA and LSF (cases) were matched with controls who underwent THA without LSF. Inclusion criteria required a minimum of 1 -year follow-up for the Hip Disability and Osteoarthritis Outcome Score Joint Replacement [HOOS-JR]. Following propensity matching for age, sex, race, body mass index, and comorbidities, 291 cases and 1,164 controls were included, with no demographic differences. Results: Patients who underwent both THA and LSF had a signi ficantly lower preoperative HOOS-JR (47 versus 50; P < .001), postoperative HOOS-JR (77 versus 85; P < .001), a signi ficant lower rate of achieving the patient acceptable symptom state (55 versus 67%; P < .001), with no signi ficant difference in delta HOOS-JR (34 versus 34; P = .834). When comparing patients undergoing THA before LSF or LSF before THA, no differences existed for preoperative HOOS-JR (50 versus 47; P = .304), but patients undergoing THA before LSF had lower postoperative HOOS-JR scores (74 versus 81; P = .034), a lower -delta HOOS-JR (27 versus 35; P = .022), and a lower rate of reaching the HOOS-JR minimal clinically important difference (62 versus 76%; P = .031). Conclusions: Patients who have a history of LSF experience a similar improvement in hip function when undergoing THA compared to patients who do not have a history of LSF. However, due to lower preoperative function, they may have a lower postoperative functional outcome ceiling. Additionally, patients undergoing THA before LSF have worse hip functional outcomes than patients undergoing LSF before THA.