Preliminary results of the Sheehan total knee prosthesis.

A review of 50 knees in 42 patients operated upon between August, 1973 and November, 1976 is presented. Following initial good results, problems have been encountered with the passage of time. Complications due to design faults, selection, and technical pitfalls are analysed. Patients who have grossly unstable and deformed knees are not suitable for this type of prosthesis. The high density polyethylene central flange in the tibial component is not strong enough to withstand valgus or varus forces. Full correction of valgus, varus, or flexion deformities is essential if late complications are to be avoided. Associated external rotation deformities in grossly valgus knees have to be fully corrected to prevent late dislocation of the patella. Our conclusion is that at present there is a place for both the hinged and hingeless type of prosthesis in total knee replacement.