[Impacted cancellous autograft for reconstructing bone defects of tibial plateau in total knee arthroplasty]

To observe the effects of a newly developed technique to transform the dish-like bone defect into contained bone defect and adopt the cancellous bone obtained from bone cut to make parvula impacted bone graft to repair the bone defect of tibial plateau in total knee arthroplasty (TKA) for osteoarthritis (OA) patients with severe varus or valgus.

54 OA patients (74 knees) with severe varus or valgus (> 25 degrees ) received TKA. The average depth of the bone defect at the tibial plateau measured in the operation was 18.23 mm and the average thickness of the bone cut was 9.97 mm. The average depth of the dish-like bone defect left after bone cutting was 8.78 mm and the defect occupied averagely 31.5% of the total section area. The sclerotic bone layer was removed to the depth of the cancellous bone by saw blade or reamer, which made the defect to be contained. Small holes were drilled in the contained bone defect. Fragments 5-8 mm in diameter were made from the cancellous bone osteotomized from the femur and tibia were impacted into the bone defect. The defect was finally covered by a bone slice to make a flat tibial section allowing the tibia prosthesis to be firmly seated on it by routine technique. Follow-up was conducted for 32.2 months on average.

The tibial deformity was repaired effectively and reliable support for the prosthesis at the tibia side was provided. Subsequent X ray films showed that no bone defect was seen under the prosthesis and the position of the prosthesis was fine. No autograft resorption and complete radiolucency between the graft and the tibial host bone appeared during the follow-up. The average KSS score raised from 45.6 preoperatively up to 94.5 postoperatively.

In comparison with other techniques, the impacted autografting technique more effectively reconstructs the bone defects of tibial plateau in TKA. The cancellous bone obtained from the bony end can be used fully, thus over-cutting can be avoided and the mechanical characteristics of the knee joint would not be disturbed.