Five-year clinical study of a novel porcine xenograft for anterior cruciate ligament reconstruction: Positive safety and performance outcomes.

Purpose: Many graft choices exist for anterior cruciate ligament (ACL) reconstruction including autograft, allograft and, to a lesser extent, synthetic graft, with all having significant limitations. While xenograft can circumvent many of these limitations, potential immunogenic response remains a concern. A novel decellularization process has been developed to remove the principal immunogenic epitopes from porcine digital extensor tendon to produce a nonimmunogenic, biomechanically appropriate ACL xenograft for clinical use. This study reports the first in-human series utilising this xenograft. Methods: This was a 5-year study of 40 patients, mean age 31.9 years (range: 18-48), 70% male, with mean follow-up of 41.9 months (6-60 months) and 19 reaching 5 years. Radiographic and MRI analysis was performed as were a variety of clinical assessments, including arthrometric measurement of anterior tibial translation, Lachman test, Pivot Shift test, International Knee Documentation Committee (IKDC) Subjective questionnaire, and Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire. All adverse events were recorded. Clinical outcomes were compared to those reported in the literature for autograft and/or allograft. Results: Adverse events included six graft ruptures which were limited to young males. No evidence of an immunogenic response was noted. Clinical outcome assessments and imaging analysis were in line with those reported in the literature for autograft and/or allograft. Conclusions: This first in-human study of a novel porcine ACL xenograft demonstrated that it is biomechanically and immunologically suitable for clinical use with no safety concerns evident. Level of Evidence: Level IV.