Abstract
Objective: To discover experimentally whether the Bisurface knee prosthesis has achieved its design objectives.
Methods: In vivo component positions of the Insall/Burnstein 2 (IB2) and the Bisurface knee under weight-bearing conditions were determined using lateral fluoroscopic views. Based on these data, contact areas in the two knees were measured using pressure-sensitive films. Stability of the posterior stabilizing cam was evaluated by means of vertical and horizontal dislocation distances.
Results: No significant adverse anterior translation in mid-flexion was observed in the Bisurface knee, because the cam worked at over 60° flexion. At flexion of 60° or more, total contact areas of the Bisurf ace knee were larger, because the cam worked as a weight-bearing surface. The dislocation distances of the Bisurface knee did not decrease with flexion.
Discussion: The current study demonstrated that the ball-and-socket joint could provide sufficient posterior stability, earlier commencement of flexion, and larger contact areas in the tibial polyethylene insert in flexion.
Conclusion: The Bisurface knee prosthesis achieved its design objectives.
