Osteochondral Grafts and Bone Transplants
Total Page：16
File Type：pdf, Size：1020Kb
OSTEOCHONDRAL GRAFTS AND BONE TRANSPLANTS Tom Merrill, D.P.M. E. Dalton McGlamry, D.P.M. Kieran Mahan, D.P.M. lntroduction Barth, Marchand, and Athausen each individually outlined various theories describing bone healing at the The use of bone graft materials has greatly enhanced turn of the century. This description of the invasion of the surgical procedures available for the reconstruction the f resh allogeneic bone by the host cells became the of the foot and leg. Bone grafts are now commonly us- "creeping substitution" theory that in part remains ed in many podiatric procedures including the Evans essentially unchanged today (2). In 1908 Judet first calcaneal osteotomy, facilitation of arthrodesis pro- reported the implantation of osteochondral grafts in ex- cedures, packing of bone cysts, and repair of nonunions. perimental animals(9), and by 1925 Lexer had As new bone graft materials are being introduced, new documented 34 hemi or whole knee allogeneic implants reconstructive procedures are being developed. in humans. Lexer followed up the patient results in 1923 and claimed a 50% success rate (10, 11). An in-depth study of bone graft healing physiology and the complex research currently being done is unfor- Limited availability and complications associated with tunately not within the scope of this text. We will pro- allogeneic bone harvesting stimulated research in preser- vide a ground work of useful information and highlight vation and storage of bone and cartilage. Bauer in 1910 several areas of clinical interest. Prior to a discussion con- with his canine studies and Inclan in 1942 with his human cerning the evolution of bone graft technology, we will studies outline the process of sterilization and delayed first outline some basic terminology. implantation of bone (2). Bone bank research continued with equipment technology advances almost yearly. The Grafts containing only bone are intercalary grafts and process of lreeze drying was developed during world war those containing bone and cartilage are osteochondral II and applied to tissue transplants (12). grafts (1). Bone that is harvested and used within the same individual is an autograft (noun) or an autogeneic Precise microscopic documentation with animal (adj) bone graft. Bone that is harvested from a cadaver models evaluated these new bone and cartilage preser- for use in another individual is an allograft (noun) or an vation techniques. The exact cellular stages of allogeneic (adj) bone graft (2). Autogeneic bone grafts are revascularization of allogeneic vs autogeneic bone grafts fresh and unprocessed. Allogeneic bone grafts are were compared in numerous studies (13-16). Herndon available either frozen or freeze dried. Several other and Chase in1952 discussed whole joint reimplantation bone graft processing methods and materials are being in 56 dogs with autogeneic, f resh allogeneic, and f rozen used experimentally (3-7). allogeneic osteochondral grafts. All the osseous graft sites appeared to unite within 6-8 weeks with no ap- History preciable difference in function. At 5 to 6 months however, the {resh allogeneic and frozen allogeneic The idea of removing a damaged structure from a grafts began to show increased density of the subchon- human being and rebuilding the body with a replace- d ral bone area. The allogeneic ioints eventually ment part f rom another individual or even a cadaver has deteriorated. The immune reaction of the host seemed enchanted society for centuries. Today we are still strug- to ignore the transplanted cartilage and instead invad- gling with the possibilities. ed the subchondral bone (17). The first experimental investigation of autografts was As technology advanced, the problems of immune with skull trephination defects by Merrem in 1810. OIIier reaction, subchondral bone invasion, and cartilage first suggested transplanting skin, periosteum, and bone preservation were addressed (18). ln the 1960's hundreds in 1867 even before Pasteur's "germ theory of disease" of dogs underwent metacarpophalangeal joint, femoral in 1878. Macewan studied under Joseph Lister and in 1BB1 condyle, and femoral head transplants (13,14, 19,20). documented the {irst successful aseptic fresh bone allograft (B). As early as 1948 Crahann described the reconstruction Fig. 1. Preoperative radiograph shows extensive osseous structural loss fig. 2. This intra-operative photograph shows fresh f rozen intercalary in rearfoot of this 34 year old female. allogeneic calcaneal graft being remodeled prior to insertion. in- Fig. 3. Postoperative radiograph taken showing restored structure of Fig, 4. Radiograph taken six mdnths Postoperative with removal of rearfoot with calcaneal graft intact. ternal fixation devices. Trabecular pattern appears to cross graft inter- face throughout. of the metacarpophalangeal joint in a human with an Current Bone Graft Utilization autogeneic metatarsal transplant in five patients (21). The fourth and f ifth metatarsals have since been commonly At Doctors Hospital we are currentiy using bone used for metacarpal replacement or mandibular condyle prepared by three different methods. Allogeneic f reeze recon stru ction (22-25). dried bone is the most frequently used. Autogeneic bone grafts are commonly used, and fresh frozen allogeneic The replacement of a calcaneus in a 34 year old female bone grafts are used when appropriate. with a f resh f rozen allogeneic calcaneal graft at Doctors Hospital by ED McClamry, D.P.M. has set another Allogeneic Freeze Dried Bone milestone in bone graft utilization. The patient's calcaneus had been removed during surgical debride- Allogeneic freeze dried bone has proven its usefulness ment of osteomyelitis over 15 years previously. (Fig 1). on many occasions. The desired shape and size of A whole calcaneus was procured under sterile conditions cancellous or cortical bone can be easily stored and and transported to Doctors Hospital in a frozen state (Fig remodeled to the individual patient's needs (Fig 5). At 2). The graft was remodeled and inserted with AO/ASIF Doctors Hospital we currently stock between 20 and 50 fixation and reattachment of the tendo achillis (Fig 3). The allogeneic freeze dried bone grafts of various sizes. We subsequent postoperative management is ongoing and commonly order a truncated iliac crest wedge of approx- has provided a foundation for further surgical ad- imately 3.5 cm x 1.6 cm x 12 cm for the Evans calcaneal vancements (Fig a). osteotomy procedure (Fig 6). truncated bone Fig. 5. Freezedried bone can be remodeled intra-operatively to specific Fig.6, Truncated iliac crest wedge with three sides of cortical bone demands of procedure. and filling of cancellous bone is ideal for Evans calcaneal osteotomy. The dehydration process has been used for centuries taining the sterile vacuum and the low moisture environ- for the preservation and storage of food. Modern techni- ment. The initial drying of the bone depends on the ques have provided a treeze-drying process that can vacuum. The higher the vacuum the faster the freeze- store tissue in a sterile vacuum sealed container in- drying, but the total water removed depends mainly on def initely (26, 27) (Fig 7). the length of the freeze-drying cycle. The longer the bone is exposed to the vacuum and low temperature environ- In the freeze-drying process the bone is procured ment, the more moisture is removed and the lower the under sterile conditions or secondarily sterilized with residual water level. Studies show a 14 day cycle can ethylene oxide or gamma irradiation. The sterile bone usually produce a freeze-dried bone graft of less than graft is then placed in a Iiquid nitrogen storage tank C70 5 gm% residual water. Quality control is constantly main- degrees F.) (12). The low temperatures of the liquid tained with 10% of the f inal product being sacrif iced for nitrogen crystallize the moisture in the bone (Fig 8). The biological testing prior to the release of the bone graft frozen graft is then moved onto the shelf of the freeze- material. dryer. The doors are closed and the vacuum pumps are turned on. The vacuum in the chamber is maintained at The donor selection process is the most important 100 millitorr or below throughout the 14 day cycle (Fig aspect of any tissue bank requirements and strict criteria (Jones WS: Regional 9). The ice crystals are directly vaporized in the vacuum are established CH, Rutledge Atlanta environment without passing through the intermediate Tissue Bank. Tissue Donation Criteria, 1987). liquid state, thus the term "freeze-dried". The water 24 hours vapor is drawn away from the bone and into a condenser. 1. Tissue donation must occur within At the end of the cycle the containers are sealed, main- of death. lig.T,Freeze-dried bone can be ordered in many shapes and sizes and Fig. 8, Liquid nitrogen (70 degrees F.) crystallizes water moisture of stored indefinitely until needed. bone, making water easy to remove in freeze-drier. 2. If tissue donation is delayed more than 12 as the f resh allogeneic graft should be implanted within hours after death, the body must be refrigerated. 48to72 hours. Fresh allogeneic grafts can be intercalary 3. The cause of death must be known. or osteochondral with the preservation techniques be- 4. The following factors exclude tissue donation: ing different for each. In addition to the standard organ a. Sepsis donor criteria previously outlined, the following clinical b. Uncontrolled wide spread infection tests are required for fresh allogeneic bone grafts (Jones c. Extra-cranial malignancies CH, Rutledge WS: Atlanta Regional Tissue Bank. Tissue d. Hepatitis Donation Criteria, 19B7): e. current I.V. drug abuse f. auto-immune disease 1. ABO blood type g. transmissible disease or infection 2. Rh factor h. tissue irradiation 3. Blood cultures x 2 (15 minutes apart) i. chronic steroid therapy aerobic and anaerobic j. Pre-existing bone disease 4. Cram stain of graft at retrieval 5.