The Impact of Concomitant LOW Back Pain (LBP) on Functional Outcomes in Total Ankle Arthroplasty (TAA)

Although numerous studies have demonstrated that concomitant low back pain (LBP) is associated with worse functional outcomes in patients undergoing total hip and knee arthroplasty, no study has analyzed its impact on patients undergoing total ankle arthroplasty (TAA). The aim of this study was to determine the prevalence of LBP in people undergoing TAA and analyze its impact on patient reported functional outcome measures (PROMs). A retrospective review was performed on data from the Vancouver End Stage Ankle Arthritis Database. In total, 87 patients undergoing TAA were studied, with patient demographics collected preoperatively, including the absence or presence of LBP. Postoperative follow-up was performed at 5 years, primarily analyzing disease-specific PROMs including the Ankle Osteoarthritis Score and Ankle Arthritis Score. The Short Form-36 was used as a secondary outcome measure to assess global function. Multivariable linear mixed-effects regression models were conducted to compare the PROM between patients with LBP with those without LBP. In total, 30 patients (35%) presented with concomitant LBP. There were no significant differences at baseline between the LBP group and no LBP group in terms of demographics or baseline primary disease-specific PROMs. At 5 years, the patients with LBP had significantly worse Ankle Arthritis Score (32 ± 23 vs 22 ± 17, p = .03), Ankle Osteoarthritis Score Total (34 ± 23 vs 22 ± 16, p = .01), and Short Form-36 physical (PCS) components summaries (33 ± 12 vs 44 ± 9, p = .001) compared to the no-LBP group. Both groups improved significantly from baseline across all outcome measures. Our study demonstrated that the prevalence of concomitant LBP in end stage ankle arthritis undergoing TAA is similar to that described in arthritic knees and hips. If present, it can be associated with worse functional outcomes in the intermediate term. However it is not a contraindication to surgery, with patients still experiencing significant improvements from baseline. Further studies are needed to evaluate if LBP influences complications, implant failure rates and survival.