Recurvatum may be the rarest deformity complicating the performance of total knee arthroplasty. The cases of four patients--two who had a primary total knee arthroplasty and two, a revision--are described, as well as the measures that are needed to correct the malalignment while avoiding the use of a highly constrained prosthesis. The principal measure that is necessary is the positioning of one of the attachments of one or both collateral ligaments on the femur in order to recreate the normal tightening action as full extension of the knee is achieved.