Introduction: Several studies have demonstrated that degenerative lumbar spine pathology has a negative impact on outcomes following total knee arthroplasty, but very few have investigated the reverse concept, the effect of knee arthritis on outcomes following spine surgery. This study evaluates patient-reported outcomes (PROs) following surgery for lumbar degenerative disease, comparing patients with concurrent knee arthritis and those without.

Methods: Patients undergoing laminectomy or laminectomy with fusion for degenerative lumbar spine disease were enrolled into a prospective registry over a two-year period. Baseline and 12-month PRO values were prospectively recorded: ODI, SF-12 PCS and MCS, VAS-Back and Leg Pain (BP, LP), and EQ-5D. Diagnosis of concurrent knee arthritis, as well as clinical (“mild”, “moderate”, “severe”) and imaging (Kellgren-Lawrence grading) were retrospectively obtained from the electronic medical record and imaging analysis. Mean absolute scores and change-scores between groups were compared using Student’s t-test. Multivariable linear regression was used to determine the effect of knee arthritis on 12-month ODI% change score.

Results: 102 patients (51 with concurrent knee arthritis at time of surgery, 51 matched controls) were evaluated. Mean 12-month absolute scores were statistically similar in knee arthritis patients for all PROs except VAS-LP: ODI% (P = 0.981), EQ-5D (P=0.679), SF-12 PCS (P=0.156), SF-12 MCS (P=0.542), VAS-BP (P=0.730), VAS-LP (P=0.009). Mean 12-month change scores were statistically similar for all PROs. Comparison of clinically graded “severe” knee arthritis patients to their matched controls yielded similar results. Multivariable linear regression demonstrated concurrent knee arthritis was not a significant predictor for ODI% 12-month change score.

Conclusions: Outside of leg pain, patients with concurrent knee arthritis do not have significantly worse pain, disability, or quality of life following lumbar spine surgery. Knee arthritis should not be a limiting factor when selecting patients for operative management. Future studies should investigate the relationship between hip arthritis and spine surgery outcomes.

Patient Care: This study helps to affirm that knee arthritis does not in fact result in worse outcomes following lumbar spine surgery. Spine surgeons can use this information in selection of patients for operative management and can treat the knee arthritis as a separate problem that is not heavily associated with spine outcomes.

Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe the relationship between concurrent knee arthritis and patient-reported outcomes following lumbar spine surgery, 2) Discuss the implications of this relationship in selection of patients for spine surgery, 3) Identify future studies evaluating the relationship between hip arthritis and outcomes following lumbar spine surgery.

References: 1. Grimm et al. Mimickers of Lumbar Radiculopathy. J Am Acad Orthop Surg. 2015 Jan;23(1):7-17. 2. Ayers et al. Patient-reported outcomes after total knee replacement vary on the basis of preoperative coexisting disease in the lumbar spine and other nonoperatively treated joints: the need for a musculoskeletal comorbidity index. J Bone Joint Surg Am. 2013 Oct 16;95(20):1833-7. 3. Prather et al. Impact of coexistent lumbar spine disorders on clinical outcomes and physician charges associated with total hip arthroplasty. Spine J. 2012 May;12(5):363-9.