No impact of severe varus deformity on clinical outcome after posterior stabilized total knee arthroplasty.

PURPOSE: Severe varus deformity may lead to premature failure of total knee arthroplasties (TKAs) because of technical difficulties associated with satisfactory alignment and good ligament balance. The aim of the study was to assess whether preoperative varus severity would affect the longevity, clinical outcomes, and complication rates of TKAs.
METHODS: From a prospectively collected database, we assessed outcomes in 168 knees that underwent primary TKAs using a single posterior stabilized design. These included 86 knees with mild preoperative deformity (varus mechanical tibiofemoral angle≤5°) and 82 knees with severe preoperative deformity (varus angle≥15°). Survivorship was analyzed by a life-table method. Clinical outcomes were also compared, including Knee Society knee and functional scores and complication rates.
RESULTS: The postoperative tibiofemoral angle of the mild varus group was 7.1°±2.5°, whereas that of the severe varus group was 6.4°±2.5° (n.s.). There were no significant differences in terms of perioperative complications. Both groups showed the same cumulative survival rate, with absence of mechanical failure, of 98% at 7 years without difference (n.s.). There were no significant between-group differences of clinical parameters throughout the each follow-up period.
CONCLUSION: The knees with preoperative severe varus deformity were achieved the results comparable to those in knees with mild varus deformity, as determined by survival rate and clinical results. These data suggest that preoperative severe varus deformities can be successfully managed and do not have any detrimental effect on the longevity and clinical outcomes after a modern posterior stabilized TKA.