MasterclassTask based rehabilitation protocol for elite athletes following Anterior Cruciate ligament reconstruction: a clinical commentary
Introduction
Anterior Cruciate ligament (ACL) injuries are one of the most common and devastating knee injuries sustained whilst participating in sport. ACL reconstruction (ACLR) remains the standard approach for athletes who aim to return to high level sporting activities (Hewett, Di Stasi, & Myer, 2013). Less than half of athletes who undergo ACLR are able to return to sport within the first year post surgery (Ardern, Webster, Taylor, & Feller, 2011), on return around 25% of the athletes returning to sport will have a subsequent second ACL injury (Hui et al., 2011, Leys et al., 2012), with the outcomes from second surgery being considerably worse (Spindler et al., 2011). Not only do these athletes returning to sport have a 1 in 4 chance of re-injuring an ACL, but regardless of whether they return to sport or not have a 1 in 2 chance of developing significantly clinical and radiological osteoarthritis (OA) of both the tibiofemoral and patellofemoral joints within 10–15 years (Crossley and Hinman, 2011, Culvenor et al., 2012, Oiestad et al., 2010). It would appear despite the advances in surgical technique and rehabilitation that the post-operative problems of these patients are not being fully addressed (Hewett et al., 2013).
Current practice around ACLR rehabilitation is quite disparate and inconsistent due to the lack of clear consistent sequential functional progressions aimed at achieving task specific goals. The current criteria for return to sport are both vague and rely on personal interpretation with the literature lacking empirically based criteria (Schmitt, Paterno, & Hewett, 2012). There is an absence of, or clear criteria for progression within the rehabilitation literature, a typical example would be from Wilk, Macrina, Cain, Dugas, and Andrews (2012) “once satisfactory strength and neuromuscular control has been demonstrated……functional activities such as running and cutting may begin 12 weeks and 16–18 weeks after surgery respectively”. Rarely if ever are the terms “satisfactory strength and neuromuscular control” defined. When objective criteria for return to sports such as hop tests and strength symmetry ratios of hamstrings and quadriceps compared to contralateral side, are offered as a minimal standard to achieve, these are clearly not detailed enough when dealing with athletes aiming for return to high level competitive sports after ACLR (Bizzini et al., 2012, Van Grinsven et al., 2010). The present criteria used for return to sport would appear to need to be revisited, especially as recurrent injury seems to be an increasing problem (Renstrom, 2013).
In the absence of clear goals any exercise rehabilitation intervention lacks focus and is likely to be less efficient and effective at returning the athlete both safely and quickly (on time) to sport and with reduced risk of re-occurrence or secondary morbidity. Establishing clear goals should aid both the athlete and the coach in seeing progression during what is a prolonged rehabilitation period, it allows those delivering the rehabilitation to the athlete to progress when targets are being met and hold and/or consolidate when they are not. It also removes the current practice of time based goals which often do not reflect the athlete's functional ability at the time they are reached. An example of this being that often athletes following UK based ACLR post-operative protocols, are not allowed to run in any form until 3 months post-operation. In terms of graft healing and maturation, the often cited reason for determining this figure, this is an irrelevant date (Claes et al., 2011, Woo et al., 2006), however this becomes a fixed point in the athlete, coaches, surgeons and rehabilitation specialists minds with the athlete failing if they cannot run at that point and on track if they are running at this time. Yet, as all practitioners realize the ability to return to running successfully is related not to healing time post-operation but on the attainment of a number of task specific skills and functional goals, if rehabilitation is geared toward these then this would allow this the athlete to be “ready when they are ready” and the multitude of intermediate markers will allow the practitioner to know exactly when they can achieve this safely.
In their reflection current issues relating to ACL injury and reconstruction Hewett et al. (2013) commented that the majority of athletes who have ACL reconstruction do not successfully return to sport and even those that do rarely are able to perform at the same level in subsequent seasons after they have returned (Ardern et al. 2011). Often the literature reports outcomes from American collegiate or varsity athletes, though often training full time and receiving full medical and rehabilitative support, these athletes may still not fully represent high performance “professional’ athletes.
The data on elite as opposed to varsity or collegiate sport presents a more mixed picture with Busfield, Kharrazi, Starkey, Lombardo, and Seegmiller (2009) reporting only 22% of national basketball association (NBA) players failed to returned to play, but of the 78% who returned, 44% were not performing at the same level, based on match statistics. Similarly, in the national football league (NFL) Shah, Andrews, Fleisig, McMichael, and Lemak (2010) found 63% of players returned to play. In a more detailed analysis of NFL players Carey, Huffman, Parekh, and Sennett (2006) found just under 80% of players returned to sport but this on average took over 12 months, and these players had typically performances deficits in the region of 30% based on match statistical data. In women's professional basketball Namdari, Scott, Milby, Baldwin, and Gwo-Chin (2011) found 78% of players returned to sport, but again there was a significant reduction in a number of sport specific game skill statistics. Athletes in high performance professional sport would appear to return to sport in greater numbers than their counterparts in varsity or collegiate sport, there is insufficient data to comment on the comparative longer term outcomes. But, what appears to be clear is that these athletes even on return to sport do not have the same impact on the games they play.
One of the main reasons for this could be the failure of the athletes to regain their pre-injury neuromuscular function (Paterno et al., 2010, Thomee et al., 2011). In a recent review paper Ardern et al. (2011) concluded that even though 85–90% of athletes obtained normal (or near normal) strength values the return to sport rate was still low. The failure to return may be related to fear of re-injury or lack of confidence with both Lentz et al. (2012) and McCulloch et al. (2012) in a similar group collegiate and varsity athletes reporting these factors to be significant in 50% of patients who failed to return to the same level of sport. Furthermore, with Lentz et al. (2012) finding the other major factor being continued knee symptoms, it may be that the patients' rehabilitation is failing to meet their needs for a complete non-problematic return to sport. This could be either in terms of the components of the rehabilitation programmes, the way they are monitored and progressed or the criteria used to measure aspects such as suitability to return to sport. There seems to be a disconnect between patients self-reported outcomes, rating their performance and their muscle functional capacity (Thomee et al., 2011). This could be because of a lack of sensitivity of the methods currently used in testing muscle function or the need for more exacting and challenging performance tests (Thomee et al., 2011).
Insufficient neuromuscular control during dynamic movements has been suggested to be a major factor in both primary (Hewett et al., 2005, Zazulak et al., 2007) and secondary (post-surgical) (Paterno et al., 2010) ACL injury risk. During various landing and cutting tasks excessive knee abduction moments (Hewett et al., 2005) and frontal plane trunk displacement (Zazulak et al., 2007) have both been predictive of ACL injury. Paterno et al. (2010) found these motion asymmetries and poor movement strategies persisted even following return to sport and were highly predictive of secondary ACL injury. It would appear that rehabilitation needs to be geared at least in part to regaining symmetrical motion and appropriate movement strategies to reduce risk of re-injury and improve function.
The literature around the outcome from ACLR surgery would appear to indicate that a high proportion of athletes do not return to the same level of sport, in the medium term, have increased risk of re-injuring the reconstructed or the contralateral knee and in the longer term of developing osteoarthritis within both the tibiofemoral and patellofemoral joints. It may be in part that these relatively poor outcomes are due to a failure to fully rehabilitate these athletes and assess them with sufficiently rigorous criteria before they pass through the stages of rehabilitation on route to return to sport. Here the failure to rehabilitate could either expose the athlete to deleterious loads they are not physically able to control, not prepared for the demands of the sport so they are physically incapable of returning or alternately the lack of rigor in the testing has left the athlete lacking confidence in their ability to return.
This contention is strongly supported by the literature which indicates that with the rate of return to sport being low, it would suggest that the tests commonly used as criteria to return athletes to unrestricted sports activities are not demanding enough or variables more important for safe return to unrestricted sports activities are not being evaluated post-surgically (Angelozzi et al., 2012, Chmielewski, 2011). Currently, based on objective criteria, there is no consensus as to when athletes should safely return to their pre-injury sport level after ACLR, especially in sports activities that require high levels of dynamic neuromuscular control coupled with power generation and absorption (Angelozzi et al., 2012, Myer et al., 2011, Myer et al., 2006). With this in mind a consensus group was set up representing physiotherapists and strength and conditioning coaches from the United Kingdom Institutes of Sport chaired by a recognized international expert in the field of ACL injury and rehabilitation research. The aim of this consensus group was to develop a robust set of progression criteria and concurrently running rehabilitation guidelines for the management of ACLR patients within the UK Institute of Sport Environment. The specific goal being to agree on a series of generic markers for progression for each of rehabilitation stages along with monitoring tools to assess loading stress on the athlete's knee.
Section snippets
Rehabilitation stages
The consensus group identified the following stages for the ACLR patient to progress through in their journey to return to their sport.
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Pre-operative
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Post-operative recovery
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Progressive limb loading
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Unilateral load acceptance
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Sport specific task training
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Unrestricted sport specific training
For each of these phases the group identified key criteria (and specific tests) which were to be achieved prior to the athlete being released to move on to the next rehabilitative phase. Within each of these phases
Discussion
Barber-Westin and Noyes (2011) in their review of return to sport criteria following ACLR noted only 13% of the studies reported any criteria for returning the athlete to sport. These criteria include muscle strength or thigh circumference (28 studies), general knee examination (15 studies), single-leg hop tests (10 studies), Lachman rating (one study) and validated questionnaires (one study). All of these criteria would seem insufficient when compared to the loading stresses the knee is
Conflict of Interest
The authors have no conflicts of interest related to this paper.
Ethical Approval
The study was literature based and no ethical approval was sort.
Funding
None declared.
Acknowledgments
The authors wish to acknowledge the role of the following people in developing the consensus: Raph Brandon (English Institute of Sport); Chris Price (English Institute of Sport); Simon Spencer (English Institute of Sport); Ashleigh Wallace (English Institute of Sport and British Olympic Association); Lindy Hardy (Scottish Institute of Sport); Phillip Glasgow (Northern Ireland Institute of Sport) and thank them for their work in the consensus development.
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