Subsequent Knee Arthroplasty Does Not Influence Patient-Reported Outcomes Following Lumbar Fusion

Study Design Retrospective Cohort Study. Objectives The impact of knee arthritis and early total knee arthroplasty (TKA) on lumbar fusion recovery remains underexplored. This study aimed to identify demographic differences between lumbar fusion patients that had subsequent TKA and patients with OA without TKA, assess perioperative differences; and compare patient-reported outcomes (PROMs). Methods Retrospective review was performed at one tertiary care center (2016–2025). Patients undergoing lumbar fusion with concurrent knee osteoarthritis and had 1-year Oswestry Disability Index (ODI) scores were included. Patients with prior joint arthroplasty or concomitant hip arthritis were excluded. Kellgren-Lawrence grading (KL) was collected via chart review and radiographs. Cohorts were stratified by future arthroplasty status and compared using bivariate analysis, with P set at <0.05. Results 148 patients were included (OA-104; TKA-44). Overall, there were no significant demographic differences between groups (Age: 64.9 years; 54.1% female). Perioperatively, patients who eventually underwent TKA had higher KL grading at the time of surgery (Grade 4: 56.8% vs 20.2%; P < 0.001). The average time to TKA from lumbar fusion was 679 days. Preoperative ODI was not significantly different between groups (42.9 vs 46.8; P = 0.174). Likewise, at 12 months, postoperative ODI (21.9 vs 27.2; P = 0.137) and improvement from baseline (−20.96 vs −19.61; P = 0.730) were similar between groups. Conclusion These findings suggest knee osteoarthritis and future TKA should not be considered a contraindication for lumbar fusion and may aid in counseling and expectation management following lumbar fusion in the presence of knee osteoarthritis.