Abstract
PurposeTo evaluate clinical ad radiological outcomes of anterior cruciate ligament (ACL) reconstruction with an immunochemically modified porcine patellar tendon xenograft controlled against human Achilles tendon allograft at 24-month minimum follow-up.Methods66 patients undergoing arthroscopic ACL reconstruction were randomized into 2 groups: 34 allografts and 32 xenografts treated to attenuate the host immune response. Follow-up was 24-month minimum. Anterior knee stability was measured as KT − 1000 side-to-side laxity difference (respect to the contralateral healthy knee). Functional performance was assessed by one-legged hop test. Objective manual pivot-shift test and subjective (IKDC, Tegner and SF-36) outcomes were collected. MRI and standard X-Ray were performed.Results61 subjects (32 allograft, 29 xenograft) were evaluated at 12 and 24 months. Six of the subjects in xenograft group (20.6%) got an infection attributed to a water-based pathogen graft contamination in processing.Intention-to-treat analysis (using the last observation carried forward imputation method) revealed higher KT − 1000 laxity in xenograft group at 24-month follow-up (P = .042). Also pivot-shift was higher in xenograft group at 12-month (P = .015) and 24-month follow-up (P = .038).Per-protocol analysis (missing/contaminated subjects excluded) did not revealed clinical differences between groups.Tibial tunnel widening in the allograft group was low, whereas xenograft tunnel widening was within the expected range of 20–35% as reported in the literature.No immunological reactivity was associated to xenograft group.ConclusionsHigh infection rate (20.6%) was reported in xenograft group. Both groups of patients achieved comparable clinical outcomes if missing/contaminated subjects are excluded. Improved harvesting/processing treatments in future studies using xenografts for ACL reconstruction are needed to reduce infection rate, otherwise xenograft should not be used in ACL reconstruction.Level of evidenceMulticenter and double-blinded Randomized Controlled Clinical Trial, Level I.
Highlights
The anterior cruciate ligament (ACL) is the key stabilizer of the knee joint and is frequently injured in athletic activities
Patients demographics Of the 66 subjects entered into the study, 61 (N = 32 in the allograft group, and 29 in the xenograft group) successfully completed the assigned 24-month minimum follow-up protocol
Five were excluded from the study as follows (Fig. 1): 2 in the allograft group and 3 in the xenograft group (1 lost to perioperative failure – stitch abscess; 1 lost to protocol violation – premature return to sport/re-trauma; and 1 elected to withdraw)
Summary
The anterior cruciate ligament (ACL) is the key stabilizer of the knee joint and is frequently injured in athletic activities. An estimated 80,000 to more than 250,000 ACL injuries occur, many in young athletes 15 to 25 years of age [9]. Surgical techniques currently shows excellent results with either the use of the patient’s own tissue to reconstruct the ACL (autograft) or, less frequently, cadaveric tissue graft (allograft). The concept of using xenograft tissue, defined as graft tissue from one species and destined for implantation in an unlike species, was introduced in 90’s. The potential advantages of xenograft use in ACL reconstruction could be to overcome the safety, mechanical and quality concerns and availability problems of allograft tissue [31]. A potential reduction of the costs could be reached using xenograft instead of allograft
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