Results of bone grafting of tibial defects in uncemented total knee replacements

Bony defects of the articular surface are frequently encountered in total knee replacement. As an alternative to excising more tibia and using a thicker tibial component, autogenous bone grafts have been used to fill these defects. The authors have analysed 43 cases in which bone grafts were used in conjunction with an uncemented tibial component. The follow-up was 2 to 7 years. The results in these cases were compared with those in a similar group using uncemented components in which bone grafting was not required. There were 15 central grafts and 28 edge grafts. All the edge grafts and seven large central grafts were fixed with screws. If the graft size was more than 1 cm2, patients were not permitted to bear weight for 4 to 6 weeks. In the others, weight bearing was allowed immediately. All grafts united, most within 6 months, and substantial collapse was not observed. Notable sinking of the tibial component occurred in one late case, in which a rotatory subluxation developed due to patellar dislocation. Collapse of the graft in a recent case, however, suggests that when large grafts are used, a heavy central stem should be used on the tibial component.