[Autologous bone grafting plus screw fixation for medial tibial defects in total knee arthroplasty]

To investigate the efficacy of autologous bone grafting plus screw fixation to reconstruct the medial tibial defects in total knee arthroplasty (TKA).

From November 2001 to November 2004, 46 patients (50 knees) with medial tibial bone defects underwent TKA at our hospital. There were 16 males (16 knees) and 30 females (34 knees). They included osteoarthritis (OA) (n = 35, 38 knees) and rheumatoid arthritis (RA) (n = 11, 12 knees). A total of 46 patients underwent three-dimensional CT (computed tomography) reconstruction to evaluate the tibial plateau defects after osteotomy. Single or double distal femoral osteotomic bone was used to reconstruct the bone defects with the hollow nail internal fixation. Another 80 TKA patients (86 knees) were randomly selected as the control group. The surgical outcome, lateral migration of tibial component and joint line elevation, etc. were analyzed and the follow-up knee society scores recorded.

The patients were followed up for 6 to 9 years. Two patients were lost to follow-up and 1 died of myocardial infarction at 5 years post-TKA in the test group. In the last follow-up, 1 case suffered deep infections and all others had no prosthetic loosening. One case (1 knee) had resorption of wedge-shaped bone graft after 8 years. The remaining graft healed and there was no screw displacement. Medial platform split fracture occurred in 3 patients (3 knees) in the OA group. The quantity of distal femoral osteotomy, thickness of polyethylene insert, tibial implant size, joint line elevation and lateral migration of tibial base were greater than the other two groups (q test, P < 0.05). The pre- and post-operative KSS scores had significant differences in each group (F test, P < 0.05). But the same group showed no significant difference at 6, 9 years (q test, P > 0.05).

As an easy and effective way of reconstructing the medial tibial bone defects, autologous bone grafting plus screw fixation can restore knee mechanical axis and stability. But in OA patients with tibial sclerosis, the complications of tibial component lateral migration, joint line elevation and splitting tibia fractures should be avoided during the reconstruction.