Status of bone banks in Japan

Proximal femoral reconstruction with impaction bone grafting and circumferential metal mesh

INTRODUCTION

Impaction bone grafting (IBG) using a circumferential metal mesh is one of the options that allow restoration of the femoral bone stock and stability of the implant in revision hip arthroplasty. Here we examine the clinical and radiographic outcome of this procedure using a cemented stem, including experimental analysis of the initial stability of mesh-grafted bone-cemented stem complexes.

METHODS

We retrospectively reviewed six hips (six patients) that had undergone femoral revisions with a circumferential metal mesh, impacted bone allografts, and a cemented stem. The mean follow-up period was 3.9 years (range 2.4-4.8 years). Hip joint function was evaluated using the Japanese Orthopaedic Association hip score, and radiographic changes were determined from radiographs. The initial resistance of mesh-grafted bone-cemented stem complexes to axial and rotational force was measured in a composite bone model with various segmental losses of the proximal femur.

RESULTS

The hip score improved from 50 (range 10-84) preoperatively to a mean of 74 (range 67-88) at the final follow-up. The overall implant survival rate was 100 % at five years when radiological loosening or revision for any reason was used as the endpoint. No stem subsided more than 3 mm vertically within one year after implantation. Computed tomography showed reconstitution of the femoral canal in a metal mesh. In mechanical analyses, there was no relationship between IBG reconstruction rates under axial compression and stem subsidence or failure load. In contrast, under rotational load, the rotation angles of the stem to the stainless steel mesh were strongly affected by the IBG reconstruction rate.

CONCLUSIONS

The short-term results show good outcomes for reconstruction of proximal bone loss with IBG and a circumferential mesh. The procedure should be applied in cases where the circumferential proximal bone loss is less than half the length of the implanted stem.

Low-intensity pulsed ultrasound therapy stimulates callus formation between host femur and cortical onlay strut allograft

Cortical onlay strut allografting is a promising surgical option to reconstruct and reinforce the deficient femur in a hip arthroplasty. However, the union of the allograft to the host bone takes a long time. To accelerate the process of cortical onlay strut allograft healing, we studied the effects of low-intensity pulsed ultrasound (LIPUS) on callus formation. From 2 wk after the operation, LIPUS was given for 20 min/d at each end of the strut allograft. The LIPUS treatment group was assigned 14 allograft transplantations, while 21 control patients were treated without LIPUS. The LIPUS treatment group formed calluses and had complete bridging between the host femur and the allograft faster after operation (16.9 and 29.4 wk after operation, respectively) compared with the control group (40.7 and 82.0 wk after operation, respectively). Our findings showed that LIPUS stimulated bone bonding between the host femur and the cortical onlay strut allografts.

Serial evaluation of human anterior cruciate ligament grafts by contrast-enhanced magnetic resonance imaging: comparison of allografts and autografts

PURPOSE

The purpose of this study was to clarify the difference in remodeling between allografts and autografts in anterior cruciate ligament reconstruction.

METHODS

We examined 24 knees with bone-patellar tendon-bone allografts and 20 knees with central-third bone-patellar tendon-bone autografts. Surgical patients from January 1997 to December 2002 were included in the study, and more than 1 year had passed since surgery. The mean postoperative follow-up was 24.0 months in the allograft group and 21.3 months in the autograft group. Patients with a positive Lachman test were excluded. The operative method and postoperative rehabilitation programs were the same. All allografts were provided by Tokai Regional Bone Bank, the only regional bone bank in Japan. Contrast-enhanced magnetic resonance imaging (1.0 T, T1-weighted, sagittal section, infusion of 0.2-mL/kg gadolinium-diethylenetriamine pentaacetic acid [Gd-DTPA]) was performed for all knees at 1, 4, 6, and 12 months after surgery and performed for some knees irregularly thereafter. The signal/noise quotient (SNQ) of grafts was calculated by use of magnetic resonance imaging based on the method of Weiler et al. (2001) as follows: SNQ = (Signal of ACL graft - Signal of quadriceps tendon)/Signal of background.

RESULTS

The SNQ of allografts was significantly lower than for autografts 12 months after surgery. As for the SNQ 1 month after surgery, there was no difference before or after Gd-DTPA infusion in the allografts; however, the SNQ was significantly higher after Gd-DTPA infusion in autografts. The SNQ after Gd-DTPA infusion continued to increase until 12 to 24 months in the allograft group but peaked at 4 or 6 months in the autograft group.

CONCLUSIONS

Compared with autologous tendons, allogeneic tendons have a slower onset and rate of revascularization.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Novel intramedullary plug with sliding mechanism used in revision total knee arthroplasty

A novel intramedullary plug with sliding mechanism has been developed and evaluated clinically in the settings of revision total knee arthroplasty (TKA). The new plug consists of a pair of specially designed components. Each component is shaped like an obliquely cut cylinder. Postoperative plain radiographs of 8 arthroplasties that include 7 stemmed femoral components and 6 stemmed tibial components (total 13 regions) were examined. No radiolucent line between the cement and the cortical bone was observed. Plugging was complete in 11 regions. No migration of the plug was observed. Slight leak of the cement was observed in 2 of 7 femoral components, but not found in tibial components. Our study demonstrated the efficacy of the plug in occluding the femoral and tibial canal completely in 11 out of 13 regions in revision TKAs.