Abstract
Total knee arthroplasty (TKA) is a very successful procedure. The alignment in TKA
has been identified as being of importance to prevent early implant failure and patient
dissatisfaction. Our hypothesis was that patients with a preoperative varus deformation
remaining in a slight varus alignment as their natural alignment after TKA will have
superior clinical results compared with patients who are restored in neutral alignment.
A total of 115 patients were corrected from varus to neutral (varus–neutral) and in
33 patients a preoperative varus alignment was kept in varus (varus). Standardized
preoperative and postoperative full-length hip–knee–ankle radiographs under full weight-bearing
conditions were performed in all patients. The patients' knees were categorized preoperatively
and postoperatively based on the angle between mechanical femoral axis and mechanical
tibial axis. Knees with alignment between ± 3 degrees were categorized as neutrally
aligned, whereas alignment within ≤ –3 degrees was categorized as varus. The Knee
Injury Osteoarthritis Outcome Score (KOOS) and Oxford Knee Score were determined retrospectively.
The varus group scored significantly better in total KOOS (p < 0.05) compared with the varus–neutral group. Also, a trend was visible in the Oxford
Knee Score but this was not significant (p > 0.05). This trend was even more evident in varus knees which were slightly undercorrected.
The results support the assumption that leaving a residual varus alignment after TKA
leads to better functional outcomes in TKA for patients with preoperative varus osteoarthritis.
Keywords
total knee arthroplasty - neutral alignment - varus alignment - total knee replacement
