Patients Requiring both Lumbar Spinal Fusion and Total Hip Arthroplasty Have Delayed Clinically Relevant Global Improvement Timelines. Findings from a Propensity Score-Matched Analysis of Time to MCID.

INTRODUCTION

Lumbar spinal fusion (LSF) influences outcomes following total hip arthroplasty (THA). However, no prior investigation has utilized a time to minimal clinically important difference (MCID) analysis. This study compared time to MCID after THA in patients who also underwent LSF versus patients who did not, and secondarily evaluated the effect of surgical sequence (LSF before versus after THA).

METHODS

We identified 183 patients from a multi-institutional registry who underwent THA and LSF within three years. A one-to-four propensity-score match generated 732 patients who did not undergo LSF. We compared rates of achievement and time to MCID in the following measures: Patient Reported Outcomes Measurement Information System (PROMIS) Physical Function Short Form-10a (PF-10a), PROMIS Global Physical, and the Hip Disability and Osteoarthritis Outcome Score-Physical Function Short Form (HOOS-PS). We also compared groups by order of procedure (LSF prior to THA: n = 117; THA prior to LSF: n = 66).

RESULTS

Patients who required both LSF and THA had delayed time to MCID in the PROMIS Global Physical (5.91 versus 5.15 months; P = 0.031) and PROMIS PF-10a (7.03 versus 6.25 months; P = 0.044). Patients who underwent LSF prior to THA had a similar time to MCID as control patients. However, patients who underwent THA prior to LSF had delayed time to MCID in the PROMIS Global Physical (7.35 months; P = 0.002) and PROMIS PF-10a (7.61 months; P = 0.028), whereas there was no difference in HOOS-PS scores (4.83 versus 5.05 months; P = 0.80).

CONCLUSION

Patients requiring both THA and LSF demonstrated delayed global recovery compared to THA alone. When stratified by surgical sequence, patients who underwent THA prior to LSF had delayed improvement timelines. Thus, performing LSF first in appropriate candidates may help ensure improvement timelines are more similar to controls.