Mobile-bearing prosthesis and intraoperative gap balancing are not predictors of superior knee flexion: a prospective randomized study

94 knees to be treated with total knee arthroplasty were randomized to receive either a posterior-stabilized mobile-bearing or fixed-bearing prosthesis. The purpose of the study was to determine how a gap balancing technique and the novel posterior-stabilized mobile-bearing prosthesis affected factors predictive of postoperative knee flexion 2 years post-operation. Results indicated that only larger pre- and intra-operative flexion angles and lower BMI values were predictive of superior knee flexion angles. As well, no superiority was noted in the novel mobile-bearing prosthesis over the conventional fixed-bearing design, as of 2 years post-operative.