Spondylolisthesis and Mismatch Deformity Affect Outcomes after Total Knee Arthroplasty

Abstract

Background Little published data currently exist regarding the potential relationships between spondylolisthesis, mismatch deformity and clinical outcomes following total knee arthroplasty (TKA). We hypothesize that pre-existing spondylolisthesis will result in decreased functional outcomes after TKA. Methods This retrospective cohort comparison of 933 TKAs was performed between January 2017–2020. TKAs were excluded if they were not performed for primary osteoarthritis (OA) or if preoperative lumbar radiographs were unavailable/inadequate to measure the degree of spondylolisthesis. 95 TKAs were subsequently available for inclusion and divided into two groups: those with spondylolisthesis and those without. Within the spondylolisthesis cohort, pelvic incidence (PI) and lumbar lordosis (LL) were calculated on lateral radiographs to determine the difference (PI-LL). Radiographs with PI-LL > 10° were then categorized as having mismatch deformity (MD). The following clinical outcomes were compared between the groups: need for manipulation under anesthesia (MUA), total postoperative arc of motion (AOM) both pre-MUA or post-MUA/revision, incidence of flexion contracture, and a need for later revision. Results 49 TKAs met the spondylolisthesis criteria, while 44 did not have spondylolisthesis. There were no significant differences in gender, body-mass-index (BMI), preoperative knee range of motion (ROM), preoperative AOM, or opiate use between the groups. TKAs with spondylolisthesis and concomitant MD were more likely to have MUA (p = 0.016), ROM < 0-120 (p < 0.014), and a decreased AOM (p < 0.02) without interventions. Conclusion Pre-existing spondylolisthesis by itself may not have adverse effect clinical results following TKA. However, spondylolisthesis increases the likelihood of developing MD. In those with both spondylolisthesis and concomitant mismatch deformities, patients had statistically and clinically significantly decreased in post-operative ROM/AOM and increased need for MUA. Surgeons should consider clinical/radiographic assessments of patients with chronic back pain who present for total joint arthroplasty.