Introduction: through the joint. In the latter cohort,


Anterior cruciate
ligaments (ACL) are one of the four main ligaments responsible for ensuring the
stability of the tibiofemoral joint. It is typically injured by active sport
players in a ‘non-contact deceleration or change of direction with a fixed foot
that produces a valgus twisting injury’. 
1 Younger active patients are the most common cohort affected
by this injury.  It is heavily linked to
sports like football and basketball and the mechanism usually depends on the
ligament strength being overcome by anterior tibial forces that can result in
quadriceps contraction and hyperextension. 1 Acutely, a ‘popping
sensation’, pain and rapid onsets (< 2 hours) of tense and large effusions are suggestive of an ACL injury. 2 However, chronically the main issue typically relates to knee instability. 3  The history and examination – particularly special tests like the anterior drawer, Lachman's and pivot shift – are usually diagnostic with magnetic resonance imaging (MRI) selected as the best imaging modality due to its superior assessment of soft tissues proving most helpful in detecting ACL tears and other soft tissue pathology associated with ACL injuries such as meniscal tears.  3 Management is normally dictated by the grading of the ligament injury (Figure 1) and the symptomatic impact on patient quality of life.  This can vary substantially between elite athletes and sedentary elderly patients who put variable load through the joint.  In the latter cohort, conservative methods are heavily favoured which are reliant on physiotherapy to maintain range of movement and hamstring and quadriceps activation.  However, surgery is often indicated if they are physically active and/or describe problematic knee instability. Reconstructive surgery is often necessary for complete ruptures of the ligament as they are usually unable to heal.  Historically these procedures have used an autograft from the iliotibial band but following a move away from open surgery towards delicate arthroscopic methods, a selection of other grafts are now considered.  4 The most common graft types include: autografts (hamstring, patellar and quadriceps tendons), allografts from donor tissues and/or synthetic equivalents. 4 Autografts, specifically hamstring tendons (HS) in the UK, are most commonly used and they, along with bone-patellar tendon-bone grafts (PT), will provide the comparative focus of the review.    Hamstring tendons have been reported as unstable, cause increased laxity and more prevalent graft failures. 5, 6 This has resulted in patellar tendon grafts, in some cases, being favoured due to their bony attachments at either end.  This is thought to improve the fixation of the tendon at both the tibial and femoral sides and provide 'superior osteointegration and healing properties'. 7 However, harvesting PT grafts involves resecting the middle portion of the tendon and this can, and has, led to donor site morbidity manifesting as anterior and/or kneeling pain.  Advances in 'new fixation methods of HS grafts has helped minimise graft fixation issues that were responsible for graft failure or a higher knee laxity' in a significant cohort of HS patients who experienced problems. 7 As a result, with a prominent shortfall of HS grafts removed, HS cohorts could now experience reduced complications and graft site morbidity relative to patients receiving PT grafts.  All papers are expected to show improved outcomes for patients following intervention but the purpose of this review is to try and identify which, if either, improves outcomes the most and which, if either, has the least associated morbidity.  To achieve this, provisional reading of the literature has identified the most common outcome measures. Given the time constraints placed on this review, the five main parameters chosen to ensure the most holistic assessment of outcome are: pain, laxity, quality of life (QOL), activity level and prevalence of osteoarthritis (OA).  The most frequently used outcome assessors for each are shown in Figure 9.  A Consultant Knee Surgeon outlined the debate around different autograft types as topical and with an interest in sport medicine - sport injuries in particular - this seemed an appropriate issue to review.  In retrospect, there appears to be no obvious 'need' for a literature review given the meta-analyses and cohort studies done within the last two years. 8, 9  However, this paper is seeking to access papers that may have been missed and focusses only on randomized control trials with the aim of adding to the evidence base or affirming their findings.  No guidelines could be found on National Institute for Clinical Excellence (NICE), Royal College of Surgeons (RCS) or British Orthopaedic Association (BOA) websites for autograft selection.  As a result, instead of comparing against a current guideline, this review will help inform the practice and autograft selections of the lower limb orthopaedic staff at the Royal Liverpool and Broadgreen University Hospital Trust (RLBUH).