Outcomes of Anterior Cruciate Ligament (ACL) Reconstruction with Fresh Frozen Allograft

The anterior cruciate ligament (ACL) is the most commonly injured ligament in the knee. Injury to the ACL often necessitates surgical reconstruction in the subject who wishes to remain active in sidestepping and pivoting activities. ACL surgery is often recommended in subjects to protect their menisci and articular cartilage from damage that can be associated with chronic ACL deficiency. Autograft tissue has traditionally been the graft of choice among most knee ligament surgeons. The ipsilateral hamstring tendon and bone-patella-tendon-bone is thought by many to be the gold standard autograft tissue of choice. Due to graft site morbidity, the necessity of revision surgeries in some cases and a more difficult rehabilitation, allograft tissue has been investigated by surgeons. As such, the popularity of allograft tissue as a graft choice has increased over the past decade. The main potential advantages of the use of an allograft in primary ACL reconstruction include no donor site morbidity, no associated weakness of the knee flexor mechanism (as in ipsilateral hamstring grafts), potentially shorter operating time, less post operative pain and availability of larger graft sizes. Allograft potential advantages also extend to revision surgery where larger grafts can be utilised and there is the option to have a bone block attached to the graft. Literature has shown that allograft is a reasonable alternative to autograft for ACL reconstruction. The majority of the literature available on allografts is from irradiated or chemically treated grafts. To date research that is published on non-irritated fresh frozen allografts including systematic reviews has demonstrated smaller sample sizes or limited measures of patient-orientated outcomes or instrumented laxity. With the increasing availability of human tissue banks and a well established screening, retrieval and testing to minimise the risk of transfer of infection with allografts, there is a need to evaluate a larger sample size of subjects with non-chemically treated grafts. The aim of this research is to assess the 2 year clinical outcomes of fresh frozen allograft in ACL reconstruction. Assessment will include knee stability, subjective outcomes, return to sport and reinjury at 1 and 2 years after surgery with standardised, reliable and validated assessment tools.