The authors retrospectively evaluated the rate of contralateral total knee arthroplasty (TKA) in 93 patients who had bilateral varus gonarthrosis and underwent unilateral TKA. Patients were divided into 3 groups according to degree of anatomical varus of the contralateral knee and/or contralateral knee pain at the time of first TKA. Group A, 25 patients, had no pain and within 10-degree deformity. Group B, 48 patients, had pain and within l0-degree deformity. Group C, 20 patients, had pain and more than 10-degree deformity. At a minimum of 2-years follow up after the first TKA, the mean function scores among the groups were significantly different (p, < 0.0001). Seventy-five percent of group C, 34% of group B and 0% of group A
underwent sequential contralateral TKA, respectively at average 6.7-month interval. Rate of contralateral TKA was high if patients had contralateral knee pain and more than 10 degrees of anatomical varus.

Keywords: Unilateral, Total knee arthroplasty, Varus knee, Gonarthrosis, Contralateral knee