Allograft versus autograft patellar tendon anterior cruciate ligament reconstruction: A 5-year follow-up.

PURPOSE: To compare the long-term results of allograft versus autograft central one-third bone-patellar tendon-bone reconstruction of the anterior cruciate ligament (ACL), 2 groups of 30 patients were evaluated subjectively and objectively at an average follow-up of 63 months (range, 55 to 78 months). TYPE OF STUDY: A prospective nonrandomized study. METHODS: All surgeries were performed endoscopically by a single surgeon using metal interference screw fixation between May 1991 and November 1992. Early aggressive rehabilitation was employed and follow-up visits at 3, 6, 12, 24, and 60 months noted swelling, pain, range of motion, and patellofemoral crepitus, and Lachman test, pivot shift test, and side-to-side arthrometer differences. RESULTS: Results were analyzed using 2-sample t test and chi-square analysis. Average age at surgery for autografts was 25 years (range, 14 to 49) and for allografts was 28 years (range, 14 to 53). The presence of meniscal tears were similar (allografts, 23 tears; autografts, 19 tears). At follow-up, no statistically significant difference was found for the presence of pain, giving way, effusion, Lachman and pivot shift results, or arthrometer measurements. Two patients, 1 allograft and 1 autograft had complete rupture of their grafts. There was no late stretching out of either graft and patients stable at 2 years were stable at 5 years, with the exception of the 1 ruptured graft in each group. CONCLUSIONS: A trend toward a greater incidence of glide on pivot testing was seen in the allografts (4 allografts v 2 autografts) but was present at 2 years and did not change at 5 years. A trend toward greater loss of extension in autografts (2.47 degrees ) than allografts (1.07 degrees ) was seen at 5-year follow-up, not seen at 2 years.

Meniscal allograft transplantation: a 1- to 5-year follow-up of 22 patients.

SUMMARY: Between October 1991 and December 1995, a total of 22 patients (23 knees) underwent meniscal transplantation with nonirradiated, cryopreserved allografts. Implantation was arthroscopically assisted using bone plugs to prevent meniscal extrusion and maintain weight-bearing functional position. Patients were evaluated with an average follow-up of 40 months (range, 13 to 69 months) using the International Knee Documentation Committee, Lysholm, and Tegner scoring systems. The most significant finding was pain reduction after implantation. Lateral and standing anteroposterior radiographs were obtained on all patients at follow-up with an average joint space loss of 0.882 mm (range, 0 to 3 mm). Magnetic resonance imaging was preformed on both knees in 12 of the 22 patients at an average of 24.4 months postoperatively. On average, the allograft meniscus was 63% (range, 31% to 100%) the size of the normal meniscus. Clinical results showed improvement of preoperative pain in all patients. Although patients continue to have good pain relief following their meniscal allograft transplantation, the average shrinkage in the size of the meniscus as shown on magnetic resonance imaging is a concern.

Use of allografts in knee reconstruction: II. Surgical considerations.

The first allograft used in the knee was articular cartilage. The need to use fresh grafts and the absence of proper instruments for shaping and sizing implants have prevented widespread usage of articular cartilage allografts. Patient selection is very important; young, active, well-motivated individuals with defects smaller than 4 cm2 caused by trauma or osteochondritis dissecans have the best results. Failure is evidenced by crumbling of the supporting bone and fragmentation of the graft, a process identical to that seen in osteonecrosis. The use of allografts to reconstruct knee ligaments has gained wider acceptance. The availability of high-quality tissue from modern tissue banks, excellent preservation methods, a decrease in short-term surgical morbidity, and results at 2- to 5-year follow-up that are essentially equivalent to those obtained with autogenous grafts have combined to make allografts an alternative to using the patient's own tissue. However, long-term stability results are needed for comparison with autogenous grafts. Replacing an unsalvageable meniscus with an allograft is an appealing concept, with the potential for restoring normal load distribution, lubrication, and stability in the knee. Healing of the grafts and pain reduction have been reported by several investigators, but concerns about graft shrinkage, central hypocellularity, and long-term functional survival remain.

Use of allografts in knee reconstruction: I. Basic science aspects and current status.

Allografts were first used in reconstructive surgery of the knee early in this century. Their widespread use and acceptance paralleled the development of modern tissue banks and our increased understanding of the immune system. Advantages of allogeneic tissue use include less surgical morbidity, shorter surgical time, smaller incisions, and the wider selection of graft sizes and types of tissue. Disadvantages include the risk of disease transmission, a slower biologic remodeling process, and the potential for a subclinical immune response. Allografts can be obtained in several forms, including fresh, fresh-frozen, freeze-dried, and cryopreserved, each with its own advantages and disadvantages. Graft sterility is most commonly ensured by aseptic techniques of harvest and procurement. Other methods, such as irradiation and chemical sterilization, have the potential to damage the collagen structure of the graft and must be used with care. Surgeons who use allografts should make sure that the tissue bank supplying their graft adheres to any applicable guidelines of the Food and Drug Administration and the American Association of Tissue Banks, and uses top-quality testing procedures. In addition, the physician should thoroughly understand the structural and biologic influence of the preservation technique used for that tissue.