gms | German Medical Science

Objectives: Degenerative conditions often cause reduced quality of life due to mobility loss and musculoskeletal pain. Therapeutic decision-making can be challenging when spinal conditions and hip or knee osteoarthritis occur simultaneously. Although studies have examined the impact of preexisting spinal conditions and previous spinal surgery on arthroplasty outcomes, there is a lack of research on the effects of prior arthroplasty on outcomes of lumbar spinal surgery. Our study evaluates the influence of prior hip arthroplasty (THA) or prior knee arthroplasty (TKA), as well as a combination of THA and TKA, on the Oswestry Disability Index (ODI) two years after elective lumbar surgery.

Methods: This retrospective study analyzed lumbar surgery patients from 2014 to 2023. The study assessed pre- and 2-year postoperative ODI, excluding patients with incomplete ODI assessment. Differences between pre- and postoperative ODI were evaluated and patients with and without ODI improvement were investigated. Patients were stratified based on their history of THA or TKA. The study examined group score differences using the Mann-Whitney-U test and univariable logistic regression. Furthermore, multivariable logistic regression was utilized to investigate the correlation between ODI improvement and prior arthroplasty, adjusted for age, sex, and BMI. The statistical significance level was set at p<0.05.

Results and conclusion: 385 patients with an average age of 65 ± 10 years (57% female) were included. Prior to lumbar surgery, 46 patients (12%) had a history of isolated THA, 34 (9%) patients had isolated TKA and 11 (3%) patients had a history of TKA and THA. An ODI improvement was achieved in 91% of the patients. 36 patients (9%) showed no ODI improvement after two years. Patients without ODI improvement were predominantly male (64%, p=<0.008). After adjusting for age, sex and BMI, a history of combined TKA and THA was significantly associated with ODI non-improvement (OR 9.96, 95% CI 2.53–38.3, p=0.001) compared to patients without prior arthroplasty. Prior isolated TKA also tended to be a risk factor for ODI non-improvement, although not statistically significant (OR 2.77, 95% CI 0.9–7.4, p=0.052) after adjusting for covariates. When not accounting for covariates, isolated TKA exhibited a significant association with ODI non-improvement (OR 2.96, 95% CI 1.0–7.6, p=0.032). A history of isolated THA was not associated with ODI non-improvement (OR 1.67, CI 0.5–4.5, p=0.339).

Patients with a prior history of concomitant TKA and THA have higher odds for ODI non-improvement two years after elective spinal surgery. These findings imply that coexisting, musculoskeletal degeneration of the spine and lower extremity might have a negative effect on a patient’s potential for improvement following lumbar surgery. The results of this study underscore also the connection not only between the hip, but also the knee and the spine, also referred to as the knee-spine syndrome.