[Experimental study on protective effect of early motion on articular cartilage after joint allograft]

OBJECTIVE

To investigate the protective effect of early motion on articular cartilage after joint allograft by performing a controlled trial between different post-operation strategies after joint allograft in an animal model.

METHODS

Twenty hemi-knee joints were harvested from 10 6-month-old New Zealand white rabbits (male or female, weighing 2.5-3.0 kg); 10 hemi-knee joints by deep frozen treatment (donors) were transplanted to unilateral knee joints (recipients) of 10 6-month-old Chinchilla rabbits (male or female, weighing 2.5-3.0 kg), which were divided into early motion group (n = 5) and sustained fixation group (n = 5); and 10 hemi-knee joints were used as blank control (n = 5) and frozen control (n = 5). The articular cartilage of allogenic joints was detected by X-ray film, gross, and histology at 6 weeks after operation.

RESULTS

Gross observation: no obvious limitation of joint movements was observed in early motion group, but obvious limitation in sustained fixation group. X-ray films: the bone ends between donor and recipient healed well with good para position and alignment on the operation day and 2 weeks after operation; at 6 weeks, angulation deformity was observed in early motion group of 3 rabbits, and para position and alignment were satisfactory in sustained fixation group. Histological observation: HE staining showed that the chondrocytes had normal quantity and morphology with few nuclear fragmentation and karyolysis in early motion group, but the quantity of chondrocytes sharply decreased with dissolved nuclei and numerous fibrous tissues in the cartilage matrix in sustained fixation group. The cell survival rate of the early motion group (49.66% +/- 2.15%) was significantly higher than that of the sustained fixation group (20.68% +/- 1.24%) (P < 0.05). Scanning electron microscopy observation: nuclear membrane was intact with chromatin condensation and edema of mitochondria and rough surfaced endoplasmic reticulum in early motion group, and that the membrane of chondrocyte vanished with blurring border between chondrocyte and matrix, rupture of nuclear membrane and the disappearance of chromatin and organelles could be found in sustained fixation group.

CONCLUSION

Early motion has protective effect on articular cartilage after joint allograft, but cannot completely prevent degeneration of the allogenic articular cartilage.

Tissue formation and vascularization in anatomically shaped human joint condyle ectopically in vivo

Scale-up of bioengineered grafts toward clinical applications is a challenge in regenerative medicine. Here, we report tissue formation and vascularization of anatomically shaped human tibial condyles ectopically with a dimension of 20 x 15 x 15 mm(3). A composite of poly-epsilon-caprolactone and hydroxyapatite was fabricated using layer deposition of three-dimensional interlaid strands with interconnecting microchannels (400 microm) and seeded with human bone marrow stem cells (hMSCs) with or without osteogenic differentiation. An overlaying layer (1 mm deep) of poly(ethylene glycol)-based hydrogel encapsulating hMSCs or hMSC-derived chondrocytes was molded into anatomic shape and anchored into microchannels by gel infusion. After 6 weeks of subcutaneous implantation in athymic rats, hMSCs generated not only significantly more blood vessels, but also significantly larger-diameter vessels than hMSC-derived osteoblasts, although hMSC-derived osteoblasts yielded mineralized tissue in microchannels. Chondrocytes in safranin-O-positive glycosaminoglycan matrix were present in the cartilage layer seeded with hMSC-derived chondrogenic cells, although significantly more cells were present in the cartilage layer seeded with hMSCs than hMSC-derived chondrocytes. Together, MSCs elaborate substantially more angiogenesis, whereas their progenies yield corresponding differentiated tissue phenotypes. Scale up is probable by incorporating a combination of stem cells and their progenies in repeating modules of internal microchannels.

[Taking ilium inner table to repair the articular surface defects of complex fracture of tibial plateau]

OBJECTIVE

To study the feasibility of application of ilium inner table to repair the articular surface defects of tibial plateau complex fractures.

METHODS

Twenty-three patients with tibial plateau complex fractures included 17 males and 6 females with an average age of 28.3 years old ranging from 18 to 51 years. The area of the articular surface defects ranged from 1 cmx2 cm to 3 cmx3 cm, averaged 6.7 cm2. Taking ilium inner table with periosteum after trimmed and implanting into the articular surface defect area with the concavity upward and drilled with diameter 1.5 mm Kirschner pin interval 3 to 4 mm. Bone grafting were placed under the ilium inner table and were fixed by T-shaped or L-shaped plate. The wounded limb were braked by plaster for 4 weeks after operation.

RESULTS

Twenty-three patients were followed-up for 8 months to 3 years, averaged 13.6 months. X-ray film showed solid union and the smooth articular surface in all cases. According to the Rasmussen evaluation system, the results were excellent in 11 cases, good in 8 cases,fair in 3 cases, poor in 1 case.

CONCLUSION

Taking ilium inner table to repair the articular surface defects of tibial plateau complex fractures is a good resolving measures. It can repaire major area of articular surface defects, restore the smooth articular surface and acquire good function of knee joint with easy to operate, less complications at donor area.

[Clinical observation of traumatically-damaged joint after its repair with transplantation of allogenic joint]

OBJECTIVE

To evaluate the long-term function of the traumatically-damaged joint after its repair with transplantation of a fresh or a frozen allogenic joint.

METHODS

From March 1977 to September 1993, 13 patients (9 males, 4 females; age, 17-55 years) with traumatically-damaged joints underwent transplantation of the fresh or the frozen allogenic joints. Five patients had 5 damaged metacarpophalangeal joints, 6 patients had 9 damaged interphalangeal joints, and 2 patients had 2 damaged elbow joints. So, the traumatic damage involved 13 patients and 16 joints. All the metacarpophalangeal joints and the interphalangeal joints were injured by machines and the 2 elbow joints were injured by road accidents. The patients were randomly divided into 2 groups: Group A (n=7) and Group B (n= 6). The 7 patients with 8 joints in Group A underwent transplantation of fresh allogenic joints; the 6 patients with 8 joints in Group B underwent transplantation of frozen allogenic joints. The allogenic joint transplants were performed in the period from immediately after the injuries to 6 months after the injuries. The motion ranges of the transplanted joints and the X-ray films were examined after operation, and the immunological examination was performed at 8 weeks after operation.

RESULTS

The time for synostosis was 5-8 months in Group A, but 4-6 months in Group B. In Group A, at 2 years after operation the metacarpophalangeal flexion was 30-40 degrees and the interphalangeal flexion was 20-30 degrees; however, at 6 or 7 years after operation the interphalangeal flexion was only 10-20 degrees. The patients undergoing the transplantation with fresh elbow joints had the elbow flexion of 60 degrees and the elbow extension of 0 degrees, and had the forearm pronation of 30 degrees and the forearm supination of 30 degrees. But in Group B, at 2 years after operation the metacarpophalangeal flexion was 60-70 degrees and the interphalangeal flexion was 40-50 degrees; at 6 or 7 years after operation the interphalangeal flexion was still 40-50 degrees. However, the patients undergoing the transplantation with frozen elbow joints had the elbow flexion of 90 degrees and the elbow extension of 0 degrees, and had the forearm pronation of 45 degrees and a forearm supination of 45 degrees. The joint motion ranges, the X-ray findings, and the immunological results in the patients undergoing the transplantation of the frozen allogenic joints were significantly better than those in the patients undergoing the transplantation of fresh allogenic joints. There was a significant difference in the immunological examination between Group A and Group B (IL-2, 21.64 +/- 3.99; CD4/CD8, 3.88 +/- 0.82 vs. IL-2, 16.63 +/- 3.11; CD4/CD8, 2.53 +/- 0.23, P<0. 01). Conclusion Repairing the traumatically-damaged joints with frozen allogenic joints is a better method of regaining the contour, movement, and complex motion of the hands.

In SCID mice with transplanted joint tissues from rheumatism patients, a model mice of human rheumatoid arthritis, anti-human fas antibody (R-125224) distributes specifically to human synovium

PURPOSE

We investigated the tissue distribution of a humanized anti-human Fas monoclonal antibody, R-125224, in SCID mice transplanted with synovial tissues from patients with rheumatoid arthritis (SCID-HuRAg mice). The binding kinetics of R-125224 was also determined, using isolated human synovial cells.

MATERIALS AND METHODS

Tissue distribution was assessed at 1, 24 and 168 h after intravenous administration of (125)I-R-125224 to SCID-HuRAg mice (0.4 mg/kg). The in vitro binding of (125)I-R-125224 to isolated human synovial cells was investigated.

RESULTS

After intravenous administration of (125)I-R-125224 to SCID-HuRAg mice, the radioactivity distributed to various tissues at 1 h. Thereafter, the radioactivity in the tissues gradually decreased except for the transplanted synovial tissues, in which the radioactivity increased in a time-dependent manner, and at 168 h, the tissue/plasma concentration ratio was about 1. The in vitro binding affinity of (125)I-R-125224 to human synovial cells was high with a dissociation constant of 1.32 +/- 0.62 nM and the binding was inhibited by non-labeled R-125224 in a concentration-dependent manner.

CONCLUSION

R-125224, a candidate compound for treating rheumatoid arthritis, specifically distributed to the pharmacological target site, human synovium transplanted in SCID mice, with high affinity.

[Repair of large bone defect due to excision of bone tumor with bone allograft]

OBJECTIVE

To study the reparative and reconstructive methods for the large bone defect due to the excision of bone tumor.

METHODS

According to the size and shape of the bone defect, we selected the proper bone and joint or manipulated bone segment of the profound hypothermia freezing allograft and gave locked intramedullary nails or steel plate and screws for stable internal fixation.

RESULTS

In the 22 cases, 20 survived without tumor and 2 died. One patient treated with the allograft of semi-knee joint was found rejection. Then the wound did not heal. After the skin flap grafting was performed, the wound still did not heal, so the patient accepted amputation(4.5%). In the other 21 cases, the X-ray and 99mTc SPECT showed some callus or concentration of nuclein which implied bone union. According to Markin bone graft criterion, the excellent rate of function recovery was 81.8%.

CONCLUSION

Allografting of bone and joint is a good and workable method in repairing and reconstructing the bone defect due to the excision of bone tumor. It should be further studied and be applied.

[Contemporary possibilities of thumb reconstruction. II. microsurgical methods]

Microsurgery has revolutionised thumb reconstruction procedures, not only allowing addition of new structures, but also performing whole reconstruction during a single, one stage procedure. This paper presents only the fundamental techniques: toe transfers (great and second toe), the wrap--around technique, trimmed-toe transfer, twisted-two-toes, free vascular joint transfer. Indications, surgical techniques, results and complications are discussed.

Survival of 25 osteoarticular allografts followed more than 10 years

An evaluation of the long-term survival rate of 25 osteoarticular allografts was made. Clinical analysis was based on the Mankin scale and the Musculoskeletal Tumor Society (MSTS) Grading system. After a mean follow-up time of 15 years 76% of the osteoarticular allografts had good or excellent rating. The MSTS scale revealed a mean score of 89% for those 20 grafts still functioning according to their primary purpose. Allograft related complications occurred in 32% of the cases being most common among malignant cases. Due to the rather good long-term results, osteoarticular allografts can still be recommended for hemicondylar allograft reconstruction in benign lesions.

Free vascularized toe joint transfer to the hand. A technique for simultaneous reconstruction of the soft tissue

Twelve patients underwent reconstruction of injured finger joints using our technique of a vascularized transfer of the second toe proximal interphalangeal joint. The age of the patients at operation ranged from 7 to 47 years and the postoperative follow-up was 9 to 48 months. All the joint transfers survived and united with resolution of the preoperative joint pain, deformity and instability. The average range of motion of the reconstructed joints was 59 degrees in the proximal interphalangeal and 54 degrees in the metacarpophalangeal joints. No patient complained of pain or functional deficits in the donor foot.

[Allografting for massive bone defect: bone and soft tissue reconstruction and postoperative rehabilitation]

OBJECTIVE

To evaluate the results of limb function and the methods of bone and soft tissue reconstruction of patients treated with allografting.

METHODS

From May 1992 to January 1999, 90 patients suffered from bone malignant tumor were treated with allografting in different methods of internal fixations. The average follow-up was 37.5 months. The limb postoperative function, complications related to different surgical methods were compared according to Enneking evaluation system.

RESULTS

Skin necrosis, infection, non-union, fracture of allograft were the main complications which affect patients' limb postoperative functions. Of the 90 fresh-frozen allografting procedures, the final results of operation showed that hip joints and knee joints were better than the shoulder joints. More than 80% of the patients treated with interlocked intramedullary nail and allograft-prosthesis combination led to an over-all result that was excellent and good. Interlocked intermedullary nail was of recommended method of internal fixation. Early exercises of operative limbs could promote function recovery.

CONCLUSION

Using of interlocked intramedullary nail and allograft-prosthesis combination are of recommended operation method and can be applied with better results, and early exercises of operative limbs will lead to better functions.

Clinical experience in allogeneic vascularized bone and joint allografting

The allotransplantation of vascularized femoral diaphyses and total knee joints is a novel approach in orthopedic surgery. Allogeneic femoral diaphyses were transplanted into three patients suffering from chondrosarcoma or posttraumatic defects. Total knee joints allografts were transplanted in five patients with large bone defects of the knee and loss of the extensor apparatus caused either by major trauma alone or infection after a major trauma. Bone segments and total joints were harvested from multi-organ donors, perfused with UW-solution and transplanted within cold ischemia times of 18-25 h. Patients were immunosuppressed postoperatively primarily with cyclosporine (Cyclosporin A) and azathioprine. Two allografts (1 femur, 1 knee) were lost due to infections. Seven of the eight patients are able to walk with full weight-bearing posttransplant. Two of the patients with transplanted joint allografts subsequently received total knee arthroplasty implantations. Vascularized bone and joint allotransplantation may serve as a last line of defense treatment before considering lower limb amputation.

Functional outcome of transplanted knee joints in dogs

Total knee joint transplantation has been performed in animal models and humans. This study investigates the impact of this operation on knee joint function in a dog model. Therefore, replantation was compared to transplantation during a 6-month follow-up period in four dogs in each group. The peak vertical ground reaction force normalized in all legs undergoing replantation and in two of four after transplantation. A third transplant recipient reduced loading from the 4th month due to a local complication, and the fourth succumbed to sepsis 3 months postoperatively. A weight-bearing index (WBI), defined as loading of the grafted divided by loading of both hind-limbs decreased from 0.48 +/- 0.08 preoperatively to 0.13 +/- 0.10 by 1 month after replantation and from 0.53 +/- 0.07 to 0 after transplantation. After 6 months, weight-bearing of all replant recipients was restored, but reduced in two transplant recipients with graft function. Full recovery after replantation, but impaired function after transplantation, was also reflected in the histological results: normal histological pictures of blood vessels, cartilage, bone and soft tissues were found in all replant recipients, but infiltrative vasculopathy indicating chronic rejection was found in the transplanted joints. The results of this animal study confirm that the procedure can lead to satisfactory functional results but also emphasize the need for perfect control of immunosuppression.

Total knee arthroplasty in patients who have massive osteoarticular allografts

The authors treated 24 patients with total knee arthroplasty who had a massive allograft used to reconstruct the knee and who later had instability, degeneration, or a fracture near the articular surface of the graft develop. Patients then were followed up for a minimum of 2 years and a mean of 8.2 years. Overall, 96% of the patients retained a functional limb, although 46% underwent revision surgery, and an additional 12% had some other major complication. Statistical analysis showed a significant negative effect of chemotherapy on revision-free survival of the prosthesis. Patients with high-grade tumors were at significantly greater risk of fracture of the allograft-prosthesis composite. Certain technical factors were identified that seemed to predispose the allograft-prosthesis reconstructions to early failure. Total knee arthroplasty can be used to treat patients with complications of massive osteoarticular allografts and may prolong the functional life of an otherwise successful limb salvage reconstruction.

Survivorship and radiographic analysis of knee osteoarticular allografts

An evaluation of long-term survival and radiographic deterioration of 118 knee osteoarticular allografts in 114 patients was performed. Radiographic analysis was done according to the Musculoskeletal Tumor Society grading system. A failure was defined as when the allograft was removed during a revision procedure or amputation. Ten patients were lost to followup during the first 2 years after surgery. Eighteen patients without allograft failures died of complications related to the tumor. Twenty-six allografts failed because of infection (13 allografts), local recurrence (eight allografts), massive resorptions (three allografts) and fractures (two allografts). Sixty-four allografts still were in place at a mean of 98 months (range, 36-360 months) after implantation. The Kaplan-Meier 5-year survival rate for the knee osteoarticular allografts was 73% and the limb preservation rate was 93%. The mean radiographic score was 83%. Sixty-four percent of the allografts showed no radiologic changes or minor articular deterioration. Fourteen percent had narrowing of the joint space of more than 2 mm, and 22% had some form of subchondral bone collapse. Five patients required joint resurfacing to preserve the original allograft. Most of the allograft failures occurred during the first 4 years, and the allograft survival rate for the current series remained unchanged after 5 years.

[Bridging long bone and joint defects with allogeneic vascularized transplants]

Three patients with large osseous defects following trauma and infection received vascularized allogeneic femoral diaphyses and five patients vascularized allogeneic total knee joints. From the surgical aspect these transplantations are technically feasible. The remaining problems are of immunological nature; at least in patients with allogeneic synovial joints, lifelong immunosuppression seems to be currently unavoidable.

Vascularized knee joint transplantation in man: a report on the first cases

Four transplantations of an allogeneic vascularized human knee joint were performed at the Trauma Center Murnau between April 1996 and July 1997. The indication for the procedure was the total loss of the knee joint including the extensor apparatus due to severe trauma. These were the first transplants of this type. Management of patients started with closure of soft-tissue defects. After successful completion, stabilization was achieved with femoral and tibial nails plus a temporary arthroplasty. AB0 compatibility and a negative cross-match were the main criteria for selecting patients for transplantation. Interlocking compression nails were used for osteosynthesis. Vascular anastomoses between graft and recipient vessels were established by the end-to-side technique. Immunosuppression was started as a quadruple induction therapy for 3 days, then reduced to a two-drug maintenance therapy with cyclosporine and azathioprine. Six months posttrans-plantation the osteotomies were bridged by callus and the patients became completely mobile. Radiographic and histological examinations revealed vital graft tissue.

Quantitative monitoring of blood supply to knee joint transplants in dogs

BACKGROUND

Transplantation of vascularized knee joints has become technically feasible, but graft rejection as well as failures of the vascular anastomoses remain critical hazards. We therefore tested the potential of repetitive non-invasive duplex sonography to detect changes of the arterial blood flow following canine knee joint transplantation.

METHODS

Four transplantations and, as controls, 4 replantations of intact canine knee joints were performed. The follow-up was 6 months. During this period, repetitive duplex sonography measurements as well as tests of knee joint function were performed. Six months postoperatively, angiographies were performed and all joints were explanted for histological investigation.

RESULTS

The luminal diameters of the implanted popliteal artery remained constant in the transplanted animals (preop. 2.6 +/- 0.2 mm, 6 months postop. 2.7 +/- 0.2 mm) but decreased in the autografted controls (preop. 2.9 +/- 0.3 mm, postop. 2.0 +/- 0.3 mm). The time-averaged velocity of the popliteal artery blood flow decreased in both groups 1 month postoperatively. Subsequently, blood flow velocity recovered in transplanted animals but remained low in replanted controls. Significant arterial wall thickening was also detected in transplanted animals as compared to controls. Six months postoperatively, hypervascularization of transplanted joints was confirmed by angiography and thickening of the arterial wall by histology. Furthermore, histology identified mild to chronic allograft rejection in all transplanted joints in spite of controlled cyclosporin A trough level immunosuppression.

CONCLUSIONS

Chronic rejection of transplanted vascularized knee joints appears to be associated with vessel wall thickening and hypervascularization rather than with vascular rarefaction (picture of the 'arbre mort') that is characteristic of the rejection of most parenchymatous organs. Duplex sonography appears to be sensitive in detecting the corresponding changes of blood supply.

Functional and morphological outcome of knee joint transplantation in dogs depends on control of rejection

BACKGROUND

The reconstruction of massive osteochondral defects extending to weight-bearing joints remains a surgical challenge. Total knee joint transplantation has been performed experimentally, but these studies lacked prospective evaluation of functional outcome, graft vascularization, and graft viability.

METHODS

Replantation and transplantation of vascularized knee joints was performed in dogs (n=4 per group), comparing functional and morphological results during a 6-month follow-up.

RESULTS

All replant recipients and three transplant recipients survived the 6-month follow-up period. At this time, duplex sonography and angiography revealed patent anastomoses in all animals. Increases in volumetric flow rates and vascular collateralization were observed in allografts, as compared with replanted joints (100+/-16 ml/min vs. 31+/-15 ml/min at 6 months after transplantation). Bone fusion at the graft-host interface was verified by fluorography in all animals at 3 months after transplantation. Six months after transplantation, microradiographies and computerized tomographies revealed spongialization of the cortical bone and filling of the medullary space by trabecular bone in transplanted joints. Such alterations were not detectable in replanted joints. Chondrocyte viability exceeded 80% in all but one transplanted joint. Lymphocyte infiltration of synovia and arterial walls was detected in all transplanted joints, suggesting the presence of chronic rejection. Weight-bearing capacity recovered in all replanted animals (weight-bearing index before transplantation: 0.499+/-0.080; 6 months after transplantation: 0.38+/-0.16) but only in two of four transplanted animals (weight-bearing index 6 months after transplantation: 0.37, 0.28, and 0.00).

CONCLUSIONS

These data demonstrate the potential of joint grafting and the critical dependence of allotransplantation on the control of rejection.

Orthotopic vascularized osteochondral allografts in an immunosuppressed rat model

This study examined the survival of orthotopic, vascularized, osteochondral allografts, following 12 weeks of immunosuppression and transfer into a naive, allograft host up to 14 weeks later, and compared the results with those previously reported for similar grafts in a heterotopic position. Knee-joint allografts between DA (donor) and Lewis (recipient) rat strains were assessed by quantitative histology up to 6 months after transplantation, and graft microcirculation was examined by India-ink infusion. Graft repopulation was assessed by re-transferring the graft to a naive, non-suppressed allograft host 12 to 26 weeks after the initial transplantation. Isografts survived for as long as grafts were examined (6 months) and showed good healing of the graft/host bone junction, although long-term isografts showed some deterioration of the growth plate. Non-suppressed allografts rejected within 2 weeks. Allografts in hosts immunosuppressed for 12 weeks remained healthy and healed in a similar manner to the isografts. Following cessation of immunosuppression, allografts progressively deteriorated, with mononuclear cell infiltration apparent in graft bone marrow and muscle in the later stages examined. Transfer to second non-suppressed hosts resulted in rapid rejection of the allografts, indicating that, as shown previously in heterotopic, osteochondral allografts, little or no graft repopulation by host-derived cells had occurred during the protected period in the first host.

Vascularized allogeneic joint, muscle, and peripheral nerve transplantation

Joint, muscle, and peripheral nerve allotransplantation was done with short-term cyclosporine immunosuppression. To investigate the effectiveness of this regimen, the allografts were examined after withdrawal of cyclosporine. Using inbred rats, vascularized orthotopic allotransplantation of the knee joint, rectus femoris muscle, and great saphenous nerve was done across a major histocompatibility complex barrier. Cyclosporine was administered for 4 to 6 weeks postoperatively, and the grafts were observed until Week 12. Long-term administration of cyclosporine and nonvascularized transplantation were used as controls. Although rejection of the allografts could be delayed for 2 to 3 weeks after the withdrawal of cyclosporine, all transplanted joints, muscles, and nerves eventually were rejected completely and immunotolerance could not be induced. The joint allografts at first achieved bony union, but eventually were destroyed because of pathologic fractures. In the group treated with long-term immunosuppression, the allografts showed no rejection and functional improvement was obtained. However, rats given a high dose (10 mg/kg per day) of cyclosporine died from adverse effects of the drug by Week 12. In the nonvascularized treatment group, the results were poor in every patient, and the need for graft vascularization for skeletal tissue allotransplantation was confirmed.

[Gamma ray-irradiation in fresh allo-joint transplantation]

In the first of a series of experiments in rat designed to assess the efficacy of gamma ray irradiation in fresh allo-joint transplantation, it was found that the optimal gamma ray dosage was 4 Gy. At this dosage level, the irradiation rays suppressed the viability of marrow cells which had the highest antigenicity, with no injury to the bone or articular cartilage. In a second experiment, a fresh homologous knee joint was irradiated at 4 Gy and then transplanted while administering the donor's splenic cell suspension (for specific immunosuppression) and the immunosuppressive agent cyclosporine (5 mg/kg) to the recipient rat. All the rats that received a pre-irradiated knee joint graft survived until sacrificed for evaluation without showing any sign of host rejection. In these rats, bone fusion had occurred between the host bone and the graft by the 8th postoperative week. Degeneration of the articular cartilage was similar between the rats that had received a pre-irradiated graft and those that had not. These findings indicated that 4 Gy gamma ray irradiation to a graft before transplantation provided an effective means of immunosuppression.

[Functional and morphological results of transplantation of vascularized knee joints in a dog model--a preliminary report]

Functional and morphological results of transplantation (n = 3) and replantation (n = 4) of vascularised total knee joints were compared in a canine model. Follow up time was 6 months. All vascular anastomoses remained patent and all osteotomies healed. Replanted animals displayed normal static weight bearing in contrast to the transplant recipients, which showed reduced weight bearing after 6 months compared to preoperative values. Mild to moderate signs of chronic allograft rejection were detected in all transplanted animals. Functional results were correlated with morphological outcome demonstrating the relevance of adequate control of rejection.

Vascularized bone allografts: review of current concepts

Advances in the field of microsurgery over the past two decades, together with the discovery of a powerful immunosuppressive, cyclosporin A, have brought vascularized osteochondral allografts closer to reality. In this review, the authors describe the history of laboratory research on vascularized osteochondral allografts using immunosuppression, as well as their experimental and preliminary clinical experiences.

Results of vascularized joint allograft under immunosuppression with cyclosporine

The effects of cyclosporine (CsA), a strong immunosuppressive drug, on vascularized allogeneic joint transplantations were examined. An orthotopical transplant model of a vascularized knee joint allograft was developed using inbred DA and Lewis rats to investigate the fate of grafts following withdrawal of short-term immunosuppression compared to continuous immunosuppression with CsA. Five isograft controls acquired solid bone union at both femur and tibia sites within 4 weeks, and joint function as skeletal support was maintained until 25 weeks. Without immunosuppression, ten allografts were severely rejected within the first week, and joint destruction occurred immediately. Twenty-five short-term immunosuppressed rats acquired solid union, but, after withdrawal of immunosuppression, grafted joints showed gradual rejection and were destroyed due to pathological fractures or joint instability, although partial revascularization from the recipient occurred. Ten allografts under continuous immunosuppression at a dose of 10 mg/kg/day showed no rejection and remained viable for 12 weeks postoperatively, but thereafter all rats died. Death was considered to be a side effect of CsA. Fifteen animals, under continuous immunosuppression at a dose of 5 mg/kg/day, showed no rejection except in the bone marrow; the grafted joint function was not effected until 25 weeks. Continuous treatment with low and nontoxic doses (5 mg/kg/day) of CsA was necessary to maintain the functions of the grafted joint.

Massive allografts in surgery of bone tumors

Large osseous and osteoarticular allografts have provided the orthopedic oncologist with a useful biological reconstructive alternative following wide en-bloc resection of bone tumors. Although the surgical procedures are complex, meticulous surgical techniques in terms of graft selection, allograft fixation, reconstruction of joint ligaments and tendons, and adequate skin coverage would produce satisfactory results in about three quarters of the patients. The potential causes of failure include allograft fracture, infection, nonunion and joint instability.

Inhibition of the immune response to experimental fresh osteoarticular allografts

The immune response to osteoarticular allografts is capable of destroying the cartilage--a tissue that has antigens on its cells identical to those on the bone and marrow cells. Osteoarticular allografts of the distal femur were performed in rats using various methods to attempt to temporarily inhibit the antibody response. The temporary systemic immunosuppressant regimens investigated were cyclophosphamide, azathioprine and prednisolone, cyclosporine A, and total lymphoid irradiation. The most successful appeared to be cyclosporine A, but significant side effects were observed. To specifically inhibit the immune response in the allograft antigens without systemically inhibiting the entire immune system, passive enhancement and preadministration of donor blood were tried. Neither was as effective as coating the donor bone with biodegradable cements, a method previously found to be successful. Cyclosporine A was investigated in dogs in a preliminary study of medial compartmental knee allografts and was found to be successful in inhibiting the antibody response and in producing a more successful graft; however, some significant side effects were similarly observed.

[Experimental study on vascularized fresh whole-joint allograft transplantation]

The vascularization of fresh whole knee and hip joints was done as part of an allograft transplant procedure involving forty rats (12 weeks old). Cyclosporin and prednisolone were injected into thirty-five recipient rats; five rats did not receive any drugs and were used as the control group. All control group rats with necrotic limbs died two to three weeks after the operation. Eleven of the twenty rats with transplanted knee joints and ten of the fifteen rats with transplanted hip joints began walking with full weight-bearing and the transplanted joints exhibited good mobility one month after the operation. Autopsy findings four, eight and sixteen weeks after the operation showed no degenerative or necrotic changes of the articular cartilage or subchondral bone of the joints. We concluded that this technique of vascularized whole-joint transplantation in rats was successful. This may be clinically applicable to reconstructive surgery after resection of diseased joints.

The use of large allografts for tumor reconstruction and salvage of the failed total hip arthroplasty

Large bone defects have become a more common orthopedic problem in recent year. This is due to the increased enthusiasm for limb salvage surgery as a technique to manage patients with primary bone tumors and for patients who have had multiple joint arthroplasties with subsequent bone loss. One technique that has proven successful for this difficult problem is the use of fresh frozen allografts to reconstruct these skeletal defects. From January 1981 until January 1987, 60 large fragment fresh frozen allografts were used for skeletal reconstruction. These grafts were divided into three basic groups: intercalary, 15; osteoarticular, 16; and allograft-prosthetic composite, 29. The diagnoses included 43 bone tumors, 16 failed total hip arthroplasties, and one traumatic bone loss. The average patient age was 39.7 years and had an average follow-up period of 24 months. The average length of allograft was 12.4 cm. Using the Enneking Functional Evaluation System, the final functional analysis revealed excellent or good results in 86% of the patients and fair or poor results in 14% of the patients. Roentgenological union at the allograft-host bone junction was achieved in 90% of the patients in a mean time of 5.8 months after surgery. An additional three patients obtained union after autogeneic bone grafting. At the time of follow-up evaluation, 92.3% of the patients were free of tumor; they had no local recurrences. The use of fresh frozen allografts represents an acceptable alternative for the reconstruction of large skeletal defects. One can expect good or excellent function for the majority of patients. The best functional results were obtained with the intercalary allografts and the allograft-prosthetic composites.

Treatment of traumatic arthritis in children

Although alternatives do exist for the treatment of traumatic arthritis in children, all efforts should be directed to treat the initial condition to avoid its progression to arthritis. Once arthritis is established, then follow the axiom, "treat patients, not x-rays." If despite all attempts at conservative treatment, a surgical option is necessary, then attention must be given to potential future growth, joint stability, and alignment, pain relief, and anticipated postoperative range of motion. All cases must be individualized because, unfortunately, none of the alternatives available is capable of guaranteeing a "normal" end result.

New concepts in bone grafting

The authors review the diagnostic and surgical imaging aspects of a number of recent bone grafting procedures in the orthopaedic management of various osseous and articular disorders. They discuss several innovative new approaches to bone grafting as well as the use of a variety of bone grafting substitute materials. They discuss the three types of bone graft available for orthopaedic reconstruction; autograft, allograft or homograft and xenograft or heterograft. They stress that an awareness of the radiographic features of each of the various bone grafting techniques is important to the physician dealing with musculoskeletal disorders in determining the results of his efforts.

Bone and joint surgery--looking ahead

Looking ahead, one envisions an era of remarkable progress in the study of the healing of bone and cartilage. The physical, biochemical, and biomechanical factors governing bone and cartilage healing will be defined and manipulated to accelerate the healing process. Joint stiffness, the undesirable sequela of many simple fractures of the hand as a result of prolonged immobilization, will be obviated. For cases of limited joint damage, techniques for joint reconstruction will be refined. For non-salvageable bone and joint destruction, microvascular allogenic transplantation of skeletal units will become a reality. Silastic implants in the wrist will become historical oddities.

Reconstruction of central metacarpal ray defects of the hand with a free vascularized double metatarsal and metatarsophalangeal joint transfer

A massive central hand defect in a 12-year-old boy was reconstructed with a free vascularized tissue block including the second and third metatarsal bones, second metatarsophalangeal joint, and common extensors of the second and third toes. Progressive bone growth has occurred and epiphyseal plates were still open at 12 months after transfer. Bone alignment and stabilization of the central hand were excellent. The foot is an excellent source of component spare parts for autogenous transfer to the hand.

Experimental hemijoint and whole-joint transplantation

Technically perfect autologous hemijoint transplants maintain biologic viability, although gradual deterioration of the joint surface may occur with the passage of long periods. Allogeneic transplants demonstrate varying degrees of degeneration, depending on the circumstances surrounding the procedure. Fresh allografts with a large amount of subchondral bone are rapidly rejected, with an immune response directed against both bony and cartilaginous components. Frozen allografts with a small amount of subchondral bone usually maintain the overall joint configuration for some time but then degenerate. In many instances the role of the immune system in rejection of joint transplants is difficult to define. The fate of whole nonvascularized knee joint transplants is comparable with that of hemitransplants. Although fresh autografts give the best results, the subchondral bone can collapse, and articular cartilage degenerates in some cases. Recent investigations of immediately revascularized canine whole knee transplants show that when the blood supply is maintained to the autograft, normal biologic function is sustained for as long as five years after grafting. When appropriate immunosuppression is used, successfully revascularized allografts survived for as long as 18 months. However, bony and cartilaginous necrosis occurs in focal areas. In any case, successfully revascularized osteochondral grafts are biologically superior to nonvascularized grafts.

Joint changes in transplanted caudal vertebrae

Both straight and bent segments of tails from 4-d-old and weaning Sprague-Dawley rats were used to study the changes which occur in symphyseal joints on transplantation to non-functional sites. In the joints from the younger donors ankylosis occurred almost invariably in the proximal end of the tail, while distally it was rarely seen unless the tail was curved, when ankylosis was visible on the inner side of the bend. The joints from the older donors showed a more varied response on transplantation. Some appeared unaltered, in others where growth continued, calcific changes were seen. In bent segments, unlike in younger ones, ankylosis occurred preferentially on the outer side of the bend. Histological examination revealed that ankylosis of the joint occurred through a process of chondroid metaplasia of the intervertebral connective tissue with subsequent replacement by bone. The metaplastic joint changes were primarily the results of pressure producing compression of the annulus fibrosus in tissues with a reduced vitality due to transplantation and lack of function.

Experimental transplantation of small joints by microvascular anastomoses

Metacarpophalangeal joints in dogs were transplanted with microvascular anastomoses. Some were transplanted as half-joints, others as whole joints, and these dogs were followed for up to 5 1/2 months. When a half-joint was transplanted within the foot, the joint movement became restricted but the vascularized half-joints were well preserved with only slight damage and well-preserved epiphyseal plates--compared to severe damage of the articular cartilage and destruction of the epiphyseal plates in the non-vascularized joint transplants. Vascularized whole joint transplants within the foot were indistinguishable macroscopically and microscopically from normal joints, and they had only a slight restriction of joint movement. They took up tetracycline from the circulation, demonstrating their viability.