Use of Femoral Head Allograft for Severe Bone Defect in Primary Total Knee Arthroplasty and Revision Total Knee Arthroplasty

PURPOSE: To investigate the clinical and radiological results after primary or revision total knee arthroplasty using fresh frozen femoral head strut allograft for severe bone defect. SUBJECTS AND METHODS: Seventeen patients (18 cases) with severe bone defect were taken primary or revision TKA from 1997 to 2001 using fresh frozen femoral head allograft. 12 cases of revision TKA and 6 of primary TKA were conducted. The average age was 66 years old(55~74) and the follow up period was 29 months(12~63 months). Bone defects were found at proximal tibia in 10 cases, distal femur in 2 and both sites in 6 cases. PCL substituting TKA with extension rod were 15, and PCL retaining TKA were 3. The clinical result was assessed with the knee score of Hospital for Special Surgery(HSS) and for assessment of allograft, simple X-ray film was employed. RESULTS: Average range of motion was increased from 71 degrees to 103 degrees and HSS score was increased from 46(18 ~68) to 83(68 ~91). With 17 of 18 femoral head strut allograft, union was seen and no clinical collapse was present. In one, partial allograft absorption was occured. The preoperative alignment was an average of 7 degrees varus(range 5 degrees~15 degrees) and postoperative alignment was averaged 6.1 degrees valgus(range 3 degrees ~7 degrees). No radiolucent lines were 2 mm or more in width, and there was no case of infection or fracture of allograft. CONCLUSIONS: Femoral head strut allograft was a satisfactory method of managing severe bone defect in primary or revision TKA.

Acetabular Revision with Hemispherical Porous Coated Prosthesis / 대한정형외과학회잡지

PURPOSE: To report the results of acetabular revisions performed with the cementless, hemi-spherical porous coated component supported by viable host bone and minimal allobone graft for acetabular deficiencies. MATERIALS AND METHODS: A retrospective study was completed for 22-revision acetabular components, using the cementless hemispherical porous coated prosthesis and minimal femoral head allograft. There was an average follow up of 48 months, with a range of 24 to 84 months. Radiographic measurements were performed in several aspects; cup-allograft contact, inclination, vertical and horizontal migration of acetabular cup, and acetabular zone by modified zone of DeLee and Charnley, in which location, size and progression or non-progression of radiolucent zone were recorded. The acetabular deficiencies were classified by the American Academy of Orthopaedic Surgeons Committee and were type I in 2 hips (9%), type II in 12 hips (55%), and type III in 8 hips (36%). Twenty acetabular cup cases of Harris-Galante II were used in this study, 1 case of Harris- Galante I, and 1 case of Duraloc. The average size of the cup was 57(44-66) mm. RESULTS: The average cup-allograft contact was 72.5% in 19 cases and we could not differentiate the margin between the host bone and the allograft in 3 cases. There was no significant vertical or horizontal migration of acetabular cup. Radiolucent zones in follow-up radiographs were 8 cases in zone IA, 4 cases in zone IB, 4 cases in zone IIB, 9 cases in zone IIC, 8 cases in zone IIIA, and 7 cases in zone IIIB. One case showed 2 mm radiolucent area in zone IIC and another case showed 3 mm radiolucent area in zone IIB, but the radiolucencies were not progressive. The remaining cases showed less than 0.5 mm radiolucent area or no radiolucent zone. The average period of bony incorporation was 13.1 months. CONCLUSIONS: We suppose that acetabular revision with the cementless hemispherical porous coated cup supported by viable host bone and minimal bone graft produces good results.

Acetabular Revision by Using Femoral Head Allograft and Uncemented Cup / 대한정형외과학회잡지

Acetabular bone deficiencies encountered during the revision hip arthroplasties should be recon- structed to provide the implant stability and to restore the normal center of rotation of hip and the leg length. We revised the loosened acetabular cup by grafting fresh-frozen bulk femoral head and inserting uncemented cup in 17 hips of 15 patients. The average follow-up period was 2 years and 3 months. The acetabular bone deficiencies were type 2A in 6 hips, type 2B in 8, type 3A in 1 and type 3B in 2 by Paprosky's classification. Three blocks of femoral head were grafted in 3 type 3 deficiencies, but only one in type 2 deficiencies. The cup-host bone contact was 41% on the average. However, the cup-host bone contact in the zone I was present only in 12 out of 17 hips and its average was 14%. Incorporation of the allograft into the host bone occurred between 5 months and 1 year and 7 months (average, 8,6 months) after revision surgery. Significant radiographic loosening sign was noted only in 2 hips which had not only type 3B bone deficiencies reconstructed with 3 blocks of femoral head allograft but also no cup-host bone contact in zone I . The bulk allograft of fresh-frozen femoral head demonstrated acceptable results in type 2 acetabular bone deficiencies, although the follow-up period was relatively short. Reconstruction of type 3B acetabular bone deficiencies by using multiple blocks of femoral head allograft had been failed. We presumed that the lack of the graft stability and the intimate contact between the grafts and host bone was the cause of failure.