Effect of osteoarthritic knee flexion deformity correction by total knee arthroplasty on sagittal spinopelvic alignment in Indian population

BACKGROUND: Sagittal alignment of the spine, pelvis, and lower extremities is essential for maintaining a stable and efficient posture and ambulation. Imbalance in any element can result in compensatory changes in the other elements. Knee flexion is a compensatory mechanism for spinopelvic sagittal alignment and is markedly affected in severe knee osteoarthritis (OA). The correction of knee flexion deformity (KFD) by total knee arthroplasty (TKA) can lead to complementary changes in the sagittal spinopelvic parameters (SSPs). AIM: To determine the SSP changes in patients with knee OA, with or without KFD undergoing TKA. METHODS: The study was conducted in 32 patients who underwent TKA. A neutral standing whole-spine lateral radiograph was performed before surgery and 3 mo after surgery in these patients. Subjects were divided into two groups (Group 1 obtained > 10° corrections in KFD; group B obtained < 10° correction). The pelvic tilt (PT), pelvic incidence (PI), sacral slope (SS), lumbar lordosis (LL), and sagittal vertical axis (SVA) were measured. RESULTS: The median of change in PT, PI, SS, LL, and SVA was 0.20 mm, 1.00 mm, 2.20 mm, −0.40 mm, and 6.8 mm, respectively. The difference in the change in SSPs between the two groups was statistically non-significant. CONCLUSION: SSPs, such as PI, PT, SS, LL, and SVA, do not change significantly following TKA in end-stage knee OA despite a significant correction (> 10°) in KFD.