Introduction:
The progression of osteoarthritis in the knee and hip, along with degeneration in the lumbar spine, can impact patients' quality of life. A history of hip or knee replacement may indicate an ongoing cascade of degeneration affecting daily activities in both the extremities and axial skeleton. The simultaneous presence of these conditions poses challenges in therapeutic decision-making and may lead to persistent complaints following operative treatments of the lumbar spine. Our study evaluates the influence of prior hip or knee arthroplasty on patient-reported outcome measures (PROMs) two years after elective lumbar surgery.
Methods:
This retrospective study focuses on patients who underwent lumbar surgery between 2014 and 2021, with a 2-year follow-up. The Oswestry Disability Index (ODI) was prospectively assessed pre- and 2 years postoperatively as well as patient satisfaction 2 years postoperatively. Patients without complete PROMs assessment were excluded from the study. The difference between pre- and postoperative ODI was evaluated. Patients with ODI improvement versus no ODI improvement were investigated. Additionally, patients were stratified based on a history of hip or knee arthroplasty. Differences in scores between groups were examined using Mann-Whitney-U test and logistic regression. Statistical significance was set at p<0.05.
Results:
A total of 385 patients (57% female) were included. Prior to lumbar surgery, there were 57 patients with a history of hip- and 45 patients with a history of knee arthroplasty. 22.9% of the patients received a single decompression, and 77.1% underwent fusion surgery. Overall, an ODI improvement was achieved in 91% of patients. 36 patients (9%) showed no ODI improvement 2 years after lumbar surgery. Of these patients, 31% with a prior knee arthroplasty had greater odds of experiencing no ODI improvement 2 years after lumbar surgery than those with no history (odds ratio (OR) 3.79, 95% confidence Interval (CI) 1.64-8.31, p=0.001). Patients who underwent hip arthroplasty were also more likely to show ODI non-improvement, although this was not significant (OR 2.19, 95% CI 0.93-4.82, p=0.059). Patients with ODI non-improvement postoperatively were predominantly male (64%, p=<0.01) and had a higher BMI (p=0.06). Patient satisfaction 2 years after lumbar surgery was not affected by prior knee- (OR 1.58, 95% CI 0.77-2.09, p=0.19) or hip (OR 1.5, 95% CI 0.78-2.79, p=0.21) arthroplasty. No differences in ODI improvement were observed between the procedures.
Discussion:
After undergoing lumbar surgery, patients with a prior history of knee replacement surgery had higher odds for ODI non-improvement 2 years after spinal surgery compared to those without arthroplasty, while patient satisfaction was not significantly affected. These findings imply that coexisting, musculoskeletal degeneration of the spine and lower extremity necessitating surgery might have a negative effect on patients' disability following lumbar surgery. Patients with a history of knee arthroplasty were prone to ODI non-improvement after lumbar surgery, which underscores the connection not only between the hip, but also the knee and the spine, also referred to as the knee-spine syndrome. Moreover, it highlights a disparity between the testing of subjective disability scores like the ODI and the satisfaction reported by patients.