Autograft versus allograft for benign lesions in children

Benign bone lesions in children are often so large in size that there is not an adequate amount of bone available for an autograft to fill the resultant cavity after surgical curettage. This study compared autografts and allografts with respect to the time required and the success of graft incorporation. Fifty-four patients with 61 lesions were studied. Lesions were classified as small volume (less than 60 cc) or large volume (more than 60 cc) and were separated into four groups: small-volume autograft, large-volume autograft, small-volume allograft, and large-volume allograft. Allografts appeared comparable to autografts when small-volume lesions were treated. The healing time was slightly longer for allografts with an average period of 21 months versus 27 months for autografts. Autografts were superior to allografts in rate and completeness of healing for solitary large lesions. This increased efficacy presumes a somewhat older child in which an adequate amount of bone is available for an autograft. A young child with multicentric or polyostotic lesions can still achieve successful incorporation with allografts. In this study, 38% healed completely and 29% healed partially. Allografts have a distinct place in the treatment of benign bone lesions in children.     

Evaluation of bone incorporation of patellar tendon autografts and allografts for ACL reconstruction using CT

Anterior cruciate ligament (ACL) reconstruction is a relatively common orthopedic procedure, with patellar tendon frequently a graft source. However, controversy exists regarding the decision to use autograft or allograft patellar tendon tissue. This experimental study used computed tomography (CT) to compare the percentage of bone graft incorporation following ACL reconstruction using autografts and allografts. Fifty consecutive patients undergoing ACL reconstruction were included in the study. The tibial bone plug was imaged with CT 1 week, 2 months, and 5 months postoperatively. Four images from each completed scan were analyzed for percentage of incorporation of the bone graft. The results of autograft and allograft incorporation for each of the time intervals were compared. No statistically significant difference was found in the amount of bone incorporation at the tibial bone plug 1 week, 2 months, and 5 months. Clinical concerns regarding slower or less complete healing of allograft bone tissue compared to autograft are not supported with regard to the grafts studied.     

Distraction Arthrodesis of the Subtalar Joint Using Allogeneic Bone Graft: A Review of 15 Cases

Distraction arthrodesis of the subtalar joint is often used for the correction of neglected calcaneal fractures. Although different techniques have been advocated, there remains some debate as to the optimal type of bone graft for this purpose. This study retrospectively reviewed one surgeon's results for distraction arthrodesis of the talocalcaneal joint for 15 consecutive feet in 15 patients using 12 frozen femoral head and 3 freeze-dried iliac crest allografts. Indications for distraction arthrodesis in this series included neglected calcaneal fracture (n = 10), failed open reduction with internal fixation (n = 3), malunion after ankle fusion (n = 1), and subtalar joint arthritis with deformity (n = 1). The mean patient age was 47.5 (range 29 to 66) years, and the mean duration of follow-up was 20.6 (range 13 to 31) months. Complete union was achieved in 14 (93.33%) feet. Orthobiological agents were used in every case, including 7 (46.67%) platelet-rich plasma, 5 (33.33%) demineralized bone matrix combined with platelet-rich plasma, 2 (13.33%) platelet-rich plasma combined with an implantable electrical bone growth stimulator, and 1 (6.67%) demineralized bone matrix only. One (6.67%) patient developed a nonunion with collapse of the allogeneic graft, requiring revision with autogenous iliac crest bone graft. There were 8 (53.33%) minor complications, including 4 (26.66%) cases with inferior heel irritation, 2 (13.33%) with sural nerve paresthesia, and 2 (13.33%) with wound dehiscence. In conclusion, the use of allograft for subtalar joint distraction arthrodesis results in similar union rates as autogenous iliac crest grafting previously reported in the literature.     

Freeze-dried segmental fibular allografts in azathioprine-treated dogs

The successful use of a bone allograft may be negated by the host's immune response. This investigation assessed the efficacy of combining freeze-dried cortical allografts in three to six weeks azathioprine-immunosuppressed dogs. Forty-eight of 94 adult mongrel dogs were initiated for this study, and 46 of 94 were previously published and recompiled. The dogs were divided into five groups and followed for six months: Group I consisted of bilateral fresh autografts as an external control; Group II assessed the effect of freeze-drying on autogenous bone; Group III compared fresh autografts with fresh allografts; Group IV assessed the effect of freeze-drying on allografts; and Group V assessed the combined effect of placing freeze-dried allografts in immunosuppressed hosts. Biweekly roentgenograms were made to evaluate the time to union and the incidence of graft fatigue failure. Mechanical graft strength was assessed by rapid torsional loading to failure at the time of sacrifice. Biologic repair was assessed with the use of tetracycline and microradiographic techniques. The incorporation and repair of a fresh cortical autograft is better than that of a freeze-dried autograft because of fractures, nonunion, or delayed union of graft-host junctions; freeze-dried autografts have increased peripheral and internal resorption, yet an increased peripheral bony callus maintains normal graft strength; freeze-dried and fresh allografts are similar in roentgenographic characteristics, mechanical strength, and in the mechanism of graft incorporation; the use of three or six weeks azathioprine therapy did not improve the fate of freeze-dried allografts.     

Graft selection in anterior cruciate ligament reconstruction

The ideal graft for use in anterior cruciate ligament reconstruction should have structural and biomechanical properties similar to those of the native ligament, permit secure fixation and rapid biologic incorporation, and limit donor site morbidity. Many options have been clinically successful, but the ideal graft remains controversial. Graft choice depends on surgeon experience and preference, tissue availability, patient activity level, comorbidities, prior surgery, and patient preference. Patellar tendon autograft, the most widely used graft source, appears to be associated with an increased incidence of anterior knee pain compared with hamstring autograft. Use of hamstring autograft is increasing. Quadriceps tendon autograft is less popular but has shown excellent clinical results with low morbidity. Improved sterilization techniques have led to increased safety and availability of allograft, although allografts have a slower rate of incorporation than do most types of autograft. No graft has clearly been shown to provide a faster return to play. However, in general, patellar tendon autografts are preferable for high-performance athletes, and hamstring autografts and allografts have some relative advantages for lower-demand individuals. No current indications exist for synthetic ligaments.     

Subtalar distraction arthrodesis using interpositional frozen structural allograft

BACKGROUND: Subtalar bone-block distraction arthrodesis using structural autograft carries the risk of donor site morbidity. Recent reports suggest that structural allograft may be an attractive alternative to structural autograft in subtalar arthrodesis. This prospective study analyzes subtalar distraction arthrodesis using interpositional structural allograft. MATERIALS AND METHODS: Between 2000 and 2006, 22 patients (24 feet; mean age, 45.6 years) underwent subtalar arthrodesis with interpositional fresh-frozen femoral head structural allograft. Indications included subtalar arthrosis, loss of heel height, and anterior ankle impingement. Clinical outcome was assessed using the AOFAS ankle-hindfoot scoring system. Time to union was determined by previously reported clinical findings and radiographic evidence for bridging trabeculation between host bone and structural allograft. RESULTS: Mean followup was 35.8 months for 20 patients (21 feet) available for followup evaluation. Union was achieved in 19 of 21 patients (90%) at a mean of 15.5 (range, 11 to 19) weeks. Mean AOFAS hindfoot score improved from 21 to 71 points (p < 0.05). Radiographic analysis suggested significant (p < 0.05) improvement in all measurements. Complications included nonunion (2), varus malalignment (1), persistent subfibular impingement (1), sural neuralgia (1), and prominent hardware (2). Both patients with nonunions had avascular bone at the arthrodesis site and used tobacco products. CONCLUSION: This study supports recent publications that subtalar arthrodesis using interpositional structural allograft can have a favorable outcome. Our clinical and radiographic results suggest that restoration of hindfoot function and dimensions with structural allograft are comparable to results reported for the same procedure using structural autograft. LEVEL OF EVIDENCE: Level IV, prospective case series.     

Rinsing morselized allografts improves bone and tissue ingrowth

Bone defects in revision hip surgery can be reconstructed with impacted morselized bone grafts. Rinsing these trabecular allografts may enhance graft incorporation by washing out immunogenic factors present in blood, marrow, and fat. However, it has been proposed that impaction of the graft releases biologically active factors, which can provide sufficient activity to stimulate new bone formation. Rinsing before impaction could enhance bone allograft incorporation, but rinsing after impaction could diminish the incorporation process of impacted bone graft. To study the effect of rinsing and impaction of morselized bone grafts on bone ingrowth, a bone chamber study was done in goats. Autografts and allografts were divided into three treatment groups: (A) impacted; (B) rinsed and impacted; and (C) rinsed, impacted, rinsed, and impacted again. Ten goats received three bone chambers in each proximal tibia. The chambers were filled with either allograft or autograft, yielding six different implants per goat. After 6 weeks, histologic analyses were done and bone and tissue ingrowth were measured. New bone and total tissue ingrowth were higher in autografts than in allografts, especially in the nonrinsed group. With rinsing, total tissue ingrowth increased in the allograft group to approach that of autografts. Rinsing after impaction did not additionally alter bone ingrowth. The current findings show that incorporation of allografts can be improved by rinsing the grafts before impaction.     

Allograft versus autograft bone in idiopathic scoliosis surgery: a multivariate statistical analysis

The use of autograft versus allograft bone in scoliosis surgery is critically evaluated by a multivariate statistical analysis. Two groups of patients matched for age, angle of curve, and length of fusion, forming a consecutive series of posterior arthrodesis for idiopathic scoliosis, were evaluated. Group A consisted of 83 patients receiving autografts, and group B consisted of 99 patients receiving allografts. There was a significant reduction in operation time in the allograft group, and blood loss also decreased. After 1 year there was no significant difference in correction of the curve. Given the problems of discomfort at the donor site scar, we recommend the use of allograft bone in scoliosis surgery.     

Selection of bone grafts for revision total hip arthroplasty

The selection of bone grafts to reconstruct deficient bone for revision hip replacement requires an understanding of specific bone graft functions and the critical steps of the biologic incorporation of the graft into the host. Bone grafts provide functions of osteogenesis, either graft derived or by osteoinduction, osteoconduction, or both, and mechanical support. Autologous cancellous bone provides excellent osteogenesis and osteoconduction without structural support. Nonvascularized cortical autografts provide mechanical support and are somewhat osteogenic. Allogeneic cancellous bone is osteoconductive and minimally osteoinductive, whereas cortical allografts provide structural support, if not freeze-dried, and are somewhat osteoconductive. Allogeneic demineralization bone matrix is highly osteoinductive. The selection of the appropriate bone graft depends on the classification of the bone deficiency. Cavitary (contained) defects can be reconstructed with cancellous morselized autograft, frozen or freeze-dried allograft, or allogeneic demineralized bone matrix. Segmental defects require bulk corticocancellous and/or cortical autografts or allografts. The ultimate incorporation of the bone graft depends on the interaction of the graft and the host's mechanical and biologic environment, and host-bone graft contact and stability. Optimum bone graft selection will enhance the clinical outcomes in revision total hip arthroplasty.     

Adhesions in a murine flexor tendon graft model: Autograft versus allograft reconstruction

Reconstruction of flexor tendons often results in adhesions that compromise joint flexion. Little is known about the factors involved in the formation of flexor tendon graft adhesions. In this study, we developed and characterized a novel mouse model of flexor digitorum longus (FDL) tendon reconstruction with live autografts or reconstituted freeze‐dried allografts. Grafted tendons were evaluated at multiple time points up to 84 days post‐reconstruction. To assess the flexion range of the metatarsophalangeal joint, we developed a quantitative outcome measure proportional to the resistance to tendon gliding due to adhesions, which we termed the Gliding Coefficient. At 14 days post‐grafting, the Gliding Coefficient was 29‐ and 26‐fold greater than normal FDL tendon for both autografts and allografts, respectively (p < 0.001), and subsequently doubled for 28‐day autografts. Interestingly, there were no significant differences in maximum tensile force or stiffness between live autograft and freeze‐dried allograft repairs over time. Histologically, autograft healing was characterized by extensive remodeling and exuberant scarring around both the ends and the body of the graft, whereas allograft scarring was abundant only near the graft–host junctions. Gene expression of GDF‐5 and VEGF were significantly increased in 28‐day autografts compared to allografts and to normal tendons. These results suggest that the biomechanical advantages for tendon reconstruction using live autografts over devitalized allografts are minimal. This mouse model can be useful in elucidating the molecular mechanisms in tendon repair and can aid in preliminary screening of molecular treatments of flexor tendon adhesions. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:824–833, 2008     

Small Size Autograft versus Large Size Allograft in Anterior Cruciate Ligament Reconstruction

BackgroundA small autograft diameter negatively affects functional outcomes, knee stability, and the risk of rerupture after anterior cruciate ligament (ACL) reconstruction, whereas the strength of allograft decreases over time. Therefore, it is not clear whether the use of smaller autografts or the use of larger allografts in ACL yields better results. The aim of this study was to compare the outcome of smaller autografts and larger allografts for ACL reconstruction.MethodsFifty-one patients who underwent ACL reconstruction with hamstring tendon autografts (size ≤ 8 mm) and 21 patients who underwent ACL reconstruction with allografts (size ≥ 10 mm) were included in our study. All patients underwent the same aggressive early postoperative rehabilitation program. There were no significant differences between the autograft and allograft groups regarding the preoperative patient age, sex, time from injury to surgery, and average follow-up time.ResultsThe mean diameter of the 4-stranded hamstring tendon grafts used as autografts was 7.48 ± 0.33 mm and the mean diameter of the allografts was 10.76 ± 0.67 mm. According to specific tests for the ACL (anterior drawer, Lachman, and pivot shift) and clinical evaluation tests (Lysholm knee scoring scale and International Knee Documentation Committee questionnaire), the final follow-up results were significantly better than the preoperative status in both autograft and allograft ACL reconstruction groups. Therefore, there were no significant differences between the autograft and allograft groups preoperatively and at the final follow-up.ConclusionsThe large size of the graft in ACL reconstruction has been reported to affect results positively. However, in our study, we could not find any significant differences between the smaller size autografts and larger size allografts in terms of inadequacy, rerupture, and final follow-up functional results. Although allografts were significantly larger than autografts, we did not have the positive effect of larger size grafts. Smaller size autografts were as effective as the larger size allografts.     

Effects of a New Allograft Processing Procedure on Graft Healing in a Canine Model: A Preliminary Study

Graft healing in vivo can be affected by allograft processing. We asked whether a new processing technique influenced graft-host healing compared with autograft and a standard processing technique in a canine ulna model. We used bilateral intercalary allografts or autografts in the ulna of 13 skeletally mature male coonhounds. Each animal received two allografts, either one autograft and one allograft, or two autografts. At term (90 days), the graft sites were harvested. We assessed union with high-resolution xray imaging. Each specimen was processed for nondecalcified histologic analysis to assess the graft-host interface. Quantitative histomorphometric analysis was performed to determine spatial location and area of bone. Radiographic analysis, histologic analysis, and histomorphometric measures revealed no differences in union, mean total bone area, or total endosteal/intramedullary bone for the new process, standard process, and autografts. Our preliminary data suggest the new processing techniques may increase the safety of allograft transplantation without adversely affecting union when compared with standard processing techniques and autograft in a canine model.     

The use of periosteally vascularized autografts to augment the fixation of large segmental allografts.

Large segmental bone grafts are a standard of reconstructing long bone defects. Nonunion or delayed union at the host-graft junction is a major complication of these procedures. In six patients, a nonunion was treated by locally available bone, vascularized by its periosteum as an onlay autograft to improve fixation and speed incorporation of the allograft into the host bone. At three months, all were pain free and using their allografts without limitation. By four months, all had roentgenographic evidence of allograft and autograft incorporation. During the follow-up period from two to four years, all have incorporated the allografts and are pain free.     

Posterior Approach for Subtalar Joint Distraction Arthrodesis by Compact External Fixation: A Technique Guide

Subtalar joint arthrodesis is a commonly used surgical procedure for the management of rearfoot pathologic features. We present a technique guide for a posterior incisional approach to subtalar joint arthrodesis for correction of a calcaneal deformity secondary to calcaneal fracture malunion. This technique uses a monolateral external fixation device for controlled distraction and intercallary allograft placement. In contrast to a standard lateral approach, this incision provides better visualization of the joint space, and the use of a distractor enhances access to the joint surfaces for fusion preparation and maintains alignment while internal fixation is applied. A 44-year-old male underwent isolated subtalar joint arthrodesis to repair a malunion of a nonsurgically managed calcaneal fracture sustained 1 year before the surgical intervention. Controlled distraction was applied using a Hoffmann^® Compact? MRI external fixation device. This device maintained distraction and tibial–calcaneal alignment until placement of the allograft–bone marrow aspirate. The use of external fixation is a viable option for distraction arthrodesis in subtalar joint fusions. It facilitates frontal plane deformity correction. We have described the surgical technique and presented a case in which the posterior approach with distraction was successfully used in subtalar joint arthrodesis. At 12 weeks postoperatively, serial radiographs displayed incorporation of the graft, with distraction maintained at the subtalar joint arthrodesis site. At the 3-month follow-up visit, the patient had successfully transitioned to weightbearing in a CAM walker without any complications.     

Efficacy of allogenic bone implants in a series of consecutive elective foot procedures

To show the efficacy of an allogenic bone graft in elective foot surgery, the authors report on 39 consecutive procedures in which allograft was implanted in 26 patients during a 30-month period. These procedures were performed for a variety of conditions, including arthrodesis, segmental lengthening, and treatment of nonunion. Allograft material consisted of freeze-dried tricortical iliac crest or demineralized bone matrix used either alone or as a composite. Allograft incorporation in all surgical procedures was retrospectively analyzed. Of 39 consecutive implant procedures, there were 38 healed sites (97%) and 1 nonunion (3%). After radiographic and clinical evaluation of allograft incorporation, the authors conclude that allogenic bone graft is a viable option for a multitude of foot conditions.     

Cadaveric elbow allografts. A six-year experience

Transplantation of total elbow allografts has been employed as a salvage procedure in an attempt to provide patients with a useful, painless range of motion of the elbow. Patients who are candidates for this procedure include those with disabling elbow joint symptoms who refuse an arthrodesis or are not candidates for conventional total elbow replacement because of excessive bone loss or young age. Allografts must be subjected to rigid internal fixation. Rush rod fixation used early in this series was associated with a high incidence of nonunion. In this series, ten patients followed for one to six years were provided with a functional elbow. However, long-term results are still unknown. Although not recommended for routine use, this operation is viewed as a salvage procedure. The use of allografts in elbow reconstruction does not preclude subsequent reconstruction with another allograft or fusion. In patients with deficient bone stock, the allografts reestablish bone mass to permit an arthrodesis or reconstructive arthroplasty.     

Early graft failure in lateral column lengthening

One hundred thirty feet in 96 children (47 girls, 49 boys) treated with lateral column lengthening to correct planovalgus foot deformities were retrospectively reviewed. Sixty-nine feet had lengthening through the neck of the calcaneus (39 allografts, 30 autografts) and 61 feet had calcaneocuboid joint lengthening and arthrodesis (58 allografts, 3 autografts). Radiographic evaluation before surgery, after surgery, and at follow-up was used to determine loss of correction, graft lucencies or fragmentation, and apparent loss of graft length. Collapse (loss of correction with concomitant loss of graft length) was observed between 0.3 and 1.3 years after surgery. Seventeen (29.3%) of the 58 calcaneocuboid joint allografts demonstrated collapse. None of the 69 intracalcaneal grafts (39 allografts, 30 autografts) and none of the 3 calcaneocuboid autografts collapsed. This series suggests that lateral column lengthening through the neck of the calcaneus may provide a more durable correction than lengthening with calcaneocuboid joint fusion.     

Acetabular augmentation in primary and revision total hip arthroplasty with cementless prostheses

Twenty-four consecutive cementless hip arthroplasties (13 autografts and 11 allografts) have been done in which large bone grafts were used to augment major acetabular deficiencies and have been followed for a minimum of 24 months with a mean of 34 and a maximum follow-up period of 55 months. The autograft augmentations were uniformly successful. Two fixation failures occurred in the allograft group. Considering the extreme deficiency in the acetabulae encountered and the absence of sufficient autograft material in this group of patients, the use of frozen allografts (although less successful in this series) seems justified. Graft resorption as determined by direct roentgenographic measurements was less than might be expected but may be a manifestation of the short-term follow-up period. Resorption, however, was greater in the allograft group and, when marked, was associated with fixation failure.     

The use of allograft bone in lumbar spine surgery

Bone grafting is an integral part of many lumbar spinal surgeries. The two choices of bone are autograft and allograft. Each source has its own advantages and disadvantages. The current study is a literature review of allograft bone use in lumbar spine surgery. Allograft bone can be procured in greater quantities than autograft. With standard protocols of harvesting, the risk of disease transfer is negligible. Only fresh-frozen and freeze-dried products are used. Allografts are incorporated slower and to a lesser degree than autografts. Fresh-frozen grafts are stronger, more immunogenic and more completely incorporated than freeze-dried grafts. Allografts used alone or combined with autografts for posterior lumbar spinal procedures have decreased fusion rates compared with autografts. If used anteriorly, allografts are well suited for reconstructive procedures and have good fusion rates, especially if combined with posterior fusions. If used in the proper situations, allograft bone can be used successfully in lumbar spine surgeries.