ISSN:1062-8592    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Experimentation with soft-tissue allografts has been reported for over 100 years. Gluck described the successful transplantation of an Achilles tendon in a chicken in 1881. Subsequent animal work with tendon and fascia transplantation continued in the early 1900s. The first attempt at preservation prior to implantation was reported in 1918. A case of human tendon allografting was reported in 1923 involving the use of an entire patella with its attached tendons. Successful fascial allograft use in humans was noted in 1927. A large amount of experimental and clinical work in flexor tendon replacement of the hand was performed in the 1960s and 1970s. However, such application was curtailed in the 1980s. Allograft tissue for anterior cruciate ligament reconstruction has seen an enormous amount of use in the last 10 years. Numerous reports of ACL allograft selection, processing and preservation, mechanical properties, rejection phenomenon, and clinical results are in the literature. Early use has been encouraging, although a possible trend toward late failure is noted. Meniscal allografts have also been used and have shown limited clinical success. The use of allograft tissue in other joints has also been reported. The concomitant rise in allograft bone and cartilage transplantation is noted, along with the development of tissue banks. Although many questions remain unanswered with respect to soft-tissue allografts, there is clearly a role for their continued use in orthopedic surgery.

ISSN:1062-8592    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Results of most anterior cruciate ligament (ACL) and meniscal allograft studies have been encouraging and have showed good potential for clinical application. However, the number of variables among studies and the fact that they are few in number made the development of conclusions difficult. With ACL allografts, most studies have used frozen bone-ACL-bone allografts in a dog model. Other graft tissues have included bone-patellar, tendon-bone, patellar-tendon strips, flexor tendons, and fascia lata; other preservation methods used have been cryopreservation and freeze-drying with ethylene oxide. Goats, sheep and primates have been some of the animal models used. Clinical, radiographic, gross pathological, histological, and mechanical evaluations have shown similar findings between allografts and autografts. This favorable comparison has been qualified in some studies with concerns that allografts have had more variable results, have healed more slowly, and have maintained less normal mechanical properties. Results have been more variable and complications greater with bone-ACL-bone grafts in dogs. Negative results in a few studies have been associated with an immune response. With medial meniscal allografts, most studies have used frozen or cryopreserved grafts in dogs. Other animal models have included the goat, sheep, and rabbit, and other preservation methods have included tissue-culture media, glutaraldehyde, and lyophilization with -v-radiation. Glutaraldehyde-treated grafts excepted, results have been generally good, regardless of the method of preservation, animal model, or other variables. Allografts have usually healed rapidly to surrounding tissue without evidence of inflammation related to an immune response. However, revitalization of the central core of the graft has not been complete at 12 months. Cryopreservation has allowed implantation of viable cells (10%) but benefits from live donor cells are not clear. Differences between cryopreserved and frozen menisci have been minimal. Autografts and allografts have had similar gross changes (i.e., shrinkage and loss of normal C-shape). Mild focal cartilage damage has occurred in areas exposed by the altered menisci. Additional studies are needed to define the best method of preservation and sterilization, the best allograft tissue, the ideal surgical technique for implantation, the role of immunological reactions, and long-term results.

ISSN:1062-8592    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Improvements in arthroscopic techniques stimulated an upsurge in arthroscopically assisted anterior cruciate ligament (ACL) reconstructions and in the use of fascia lata, bone-patella tendon-bone, and Achilles tendon allografts in these operations. Biomechanically and biologically aseptically excised and processed frozen or freeze-dned allografts appear to be comparable to autografts. Complications have been reported with ethylene oxide sterilized allografts. These have been attributed to the residues of ethylene oxide sterilization. Irradiated allografts are biomechanically weaker than their nonirradi-ated counterparts. Of concern to orthopaedic surgeons is the possibility of transmission of HIV and other infections with allografts used in ACL reconstructions. This possibility can be minimized by careful multiphase screening and laboratory investigations of donors from whom the allografts are obtained. Orthopaedic surgeons should be familiar with this process and with the risks associated with omissions of steps in this comprehensive process.

ISSN:1062-8592    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

There exists what is commonly referred to as a “window” of se-ronegativity following human immunodeficiency virus (HIV) infection. Potential bone and soft-tissue donors may be infectious with HIV without the virus having been detected by available antibody tests. Graft retrieval may be carried out in either a sterile or clean, nonsterile manner. Deep-freezing and freeze-drying are two commonly used processing and preservation methods. A screened donor who was in this window of seronegativity underwent vascular organ and tissue harvest. All vascular organs and the majority of minimally processed fresh-frozen grafts later tested HIV-antibody-positive. There are no known cases of HIV transmission in patients who received freeze-dried bone and soft-tissue grafts.

ISSN:1062-8592    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

The biomechanical factors that influence the ultimate outcome of ligament reconstruction are described and discussed in the context of experimental studies on allograft reconstruction. Proper choice of animal model and experimental design is emphasized. Selection of appropriate allograft tissue is discussed in terms of the structural properties of the reconstructed bone-soft tissue-bone complex, and the material properties of the soft-tissue substance. The effects of processing and sterilization on graft biomechanical properties are outlined. The requirements for proper initial fixation are presented, and the relative merits of the different methods are discussed. The in vivo changes in allograft properties are shown to be similar to those found for autograft tissues. In general, studies have found that an anterior cruciate ligament allograft with stiffness and ultimate load approaching 30–35% of control values at 1 year postoperatively is typical. Methods used to examine joint kinematics are described, and the results of kinematic analysis of healed allograft reconstructions are summarized. Restoration of normal knee kinematics is emphasized to be the ultimate goal of any ligament reconstruction procedure.

ISSN:1062-8592    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Allografts represent an alternative to autogenous tissue for use in reconstructive surgery of the anterior cruciate ligament (ACL). There are many issues for the surgeon to consider when using these tissues. Among these issues is the effect of processing protocols used by the tissue bank supplying the allografts. Ethylene oxide-sterilized allografts for ACL reconstruction have been reported to be associated with an intraarticular reaction. This reaction has been characterized by a persistent effusion and graft fragmentation requiring removal of the graft. It has been suggested that two byproducts of ethylene oxide sterilization, ethylene chlorohydrin (EC) and ethylene glycol (EG), are possibly responsible for these reactions. Studies attempting to elicit this intraarticular reaction as seen in humans using a rabbit model were unsuccessful. These animal-model studies included intraarticular injections of solutions of EC and EG, ethylene oxide-sterilized patellar tendon particulates, and ACL reconstruction using ethylene oxide-sterilized patellar tendon. The intraarticular reactions described in this article have not been reported because most tissue banks now procure soft tissues aseptically and no longer sterilize them with ethylene oxide for use in transplantation.

ISSN:1062-8592    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

The history of fascia lata allograft use in general and in anterior cruciate ligament (ACL) reconstruction is presented. A review of mechanical data reveals that a 10-cm wide freeze-dried fascia lata graft will supply 231% the strength of an intact ACL. We present a technique for using a rolled fascia lata graft endoscopically for ACL reconstruction. The technique draws strength from lateral fluoroscopic imaging during tunnel preparation and graft placement. Clinical results in 100 patients followed an average of 3.4 years show the grafts intact in 98 patients with no laxity on KT-1000 testing compared to the other knee in 74 patients, and 1–5 mm increased laxity in 24 patients. There were two ruptured grafts. Ninety-three percent of the patients stated that they were functioning at their desired level of activity. We conclude that the described technique of ACL reconstruction with freeze-dried fascia lata allograft consistently gives an excellent clinical result.

ISSN:1062-8592    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Two-hundred-sixteen allograft bone-patellar ligament-bone fresh-frozen allograft anterior cruciate ligament (ACL) reconstructions were performed from September 1985 to May 1992. All patients underwent an aggressive rehabilitation program that emphasized early unrestricted motion and functional weight-bearing, with return to unrestricted sports activities typically occurring 6 months after surgery. Ninety-three patients returned for follow-up evaluation an average of 30 months (range 24–51 months) after reconstruction. Ninety-two percent of patients felt their knees had improved or returned to normal following surgery, and 87% achieved good or excellent results when evaluated with the Lysholm Knee Score. Objectively, 89% of patients exhibited a 0 to 1 + Lachman score with a solid endpoint. and 86% had =≤ 3 mm difference on KT-1000 testing. Using the modified Hughston Knee Evaluation system to combine the subjective, functional, and objective portions of the evaluation, 80% of the patients achieved good or excellent results. There were 10 graft failures. Our results are comparable to those previously reported in the literature for both allograft and autograft ACL reconstruction. We have found our results using allograft tissue in ACL reconstruction to be of equal value to those obtained with autograft tissue, with allograft recipients experiencing less early postoperative morbidity.

ISSN:1062-8592    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Although there is very little in the current literature directly comparing allograft and autograft anterior cruciate ligament reconstruction, preliminary data demonstrate very little difference in the outcome of these two procedures. Animal studies seem to indicate incorporation of allograft tissue that is somewhat delayed when compared to autograft. Early clinical reports are generally favorable. We have reviewed the limited data available on this subject; additional study in this area is clearly needed, however.

ISSN:1062-8592    

出版商:OVID    

年代:1993

数据来源: OVID