Fracture of the central polyethylene tibial spine in posterior stabilized total knee arthroplasty.

Between 1993 and 1998, 332 I-BII (Insall Burstein II) prostheses were implanted in our department. We studied 5 cases of tibial polyethylene spine fractures. The fractures occurred 3 to 5 years following the surgery. All cases with fractures had mild medial laxity that was noted on follow-up of 2 to 3 years following arthroplasty. One also developed mild hyperextension. All the patients had a revision surgery. In 2 cases, the polyethylene was changed to a thicker one, together with medial reinforcement. Three cases were revised to a rotating hinge prosthesis.