Article Text
PDF
Abstract
Over two million anterior cruciate ligament (ACL) injuries occur worldwide annually, and the greater prevalence for ACL injury in young female athletes is one of the major problems in sports medicine. Optimal treatment of ACL injury requires individualised management. Patient selection is of utmost importance, and so is respect for the patient's functional demands and interests. All patients with an ACL tear may not need surgery, however athletes and persons with an active lifestyle with high knee functional demands including cutting motions need and should be offered surgery. In many cases it may not be the choice of graft or technique that is the key for success, but the choice of surgeon. The surgeon should be experienced and use a reconstructive procedure he/she knows very well and is comfortable with. The development of osteoarthritis after an ACL injury depends very much on the injury mechanism and concurrent meniscal injury, as knee articular cartilage continues to heal for 1–2 years after an ACL injury. Therefore the surgeon and rehabilitation team must pay attention to the rehabilitation process and to the decision when to return to sport. Return to sport must be carefully considered, as top-level sport in itself is one main risk factor for osteoarthritis after ACL injury. The present criteria for return to sport need to be revisited, also due to the fact that recurrent injury seems to be an increasing problem. ACL injury prevention programmes are now available in some sports. The key issue for a prevention programme to be successful is proper implementation. Vital factors for success include the individual coaching of the player and well controlled compliance with the training programme. Preventive activities should be more actively supported by the involved athletic community. Despite substantial advances in the field of ACL injury over the past 40 years, substantial management challenges remain.
- Injury Prevention
- ACL
Statistics from Altmetric.com
Two million anterior cruciate ligament injuries annually
Over two million anterior cruciate ligament (ACL) injuries occur worldwide annually.1 There are 81–85 ACL injuries per 100 000 citizens in society, which is higher than previously recorded.2 ,3
The rate of ACL surgeries differs between the sexes, especially in the second decade of life. Non-contact ACL injury among female athletes is 3–5 times more common than men in sports such as team handball, football (soccer) and basketball.4 ,5 A meta-analysis shows a 2.6 times overall increased risk.6 Interestingly the rate of ACL injury decreases as the female basketball athlete matures and the level of play increases; the ratio of female to male injuries decreases at the college level, and approximates 1 at the professional level.
Understanding the cause of sports injury requires a precise description of the injury mechanism. Kinematic and kinetic gender differences exist that may render women more susceptible than men to ACL injury. The most common gender differences are reduced knee and hip flexion when landing, increased knee valgus, internal rotation of the femur and high quadriceps activity unbalanced by the hamstrings in female athletes.7
Concerning other risk factors there is no definite evidence that any anatomical factor is reliably associated across age groups and sexes with an increased risk of injury. There are some indications that the menstrual cycle may have an effect on anterior–posterior laxity of the knee.8
Personal reflection
The greatest prevalence for ACL injury in female athletes truly exists in the 14–18 years age group. Women demonstrate more ‘quadriceps dominant’ neuromuscular patterns and the hamstring recruitment has been shown to be significantly higher in men than in women. This greater prevalence for ACL injury in young female athletes must be considered to be one of the major problems in sports medicine. As new effective preventive programmes are emerging, a new challenge will be to implement them effectively. This is considered further this below.
The greatest prevalence for ACL injury in female athletes truly exists in the 14–18 years age group...This greater prevalence for ACL injury in young female athletes must be considered to be one of the major problems in sports medicine.
How to make a correct diagnosis
Some question the accuracy of current ACL diagnostic tests. The first clinical examination after an acute knee trauma seems to have a low diagnostic value.9 Studies indicate that a positive result for the pivot shift test is the best for ruling in an ACL rupture whereas a negative result of the Lachman test is the best for ruling out an ACL rupture.10 The Lachman test is the better overall test at ruling in and ruling out ACL ruptures. Further assessment with MRI improves the chances of a correct diagnosis of the overall intra-articular pathology.9
Personal reflection
A well-taken history by itself will make an experienced knee expert strongly suspect an ACL tear in over 80% of cases. The key element in the history is primarily the injury mechanism, including a feeling of a pop at the time of injury and secondarily the status of the knee with pain, swelling, inability to keep playing etc. and giving way when bearing weight.
When history is combined with physical examination findings, diagnostic accuracy can exceed 90%.
When history is combined with physical examination findings, diagnostic accuracy can exceed 90%. Although MRI is routinely not needed to establish the ACL diagnosis itself, it should be pointed out that MRI is sensitive and specific for picking up ACL injuries. MRI is useful to check out for concurrent injuries such as meniscal injury and articular cartilage damage and often in predicting the prognosis of the injury. MRI is however expensive, sometimes unnecessary and can indicate damage in the knee that may not be of greater clinical significance.
Are outcomes overestimated? Using a valid outcome instrument
Orthopaedic surgeons mostly report very good results following ACL surgery. During my clinics I regularly team up with experienced physical therapists. Over time they have been advocating that, in their view, many patients with ACL reconstruction were not doing as well as reported by the surgeons. The logical question that keeps coming up is: ‘Do ACL surgeons overestimate their outcomes after ACL reconstruction?’ On average, surgeons rate the outcome with regard to knee function and activity level as significantly better (40% to 60%!) than patients.11 This demonstrates the importance of using valid outcome instruments.
Do ACL surgeons overestimate their outcomes after ACL reconstruction? On average, surgeons rate the outcome with regard to knee function and activity level as significantly better (40% to 60%!) than patients.
Concerning outcomes, there was a ground-breaking development during the 1990s. Before the 1990s, the outcome after ACL surgery was mostly evaluated by using laxity tests, one leg jumps and so on. At the beginning of the 1990s, doctors finally started to ask the ACL reconstructed athletes how they really felt! At the end of the 1990s, there was a paradigm shift in orthopaedic sports medicine concerning outcomes in ACL surgery. The primary outcome instrument must reflect the patient's perspective, be valid and relevant for the patients rather than the knee pathology. A good example of this is the Knee Injury and Osteoarthritis Outcome Score (KOOS) score.11 Another good example is the development and publication of patient-reported outcomes (PROMS) used by the National Health Service in the UK. PROMS include questionnaires on pain, mobility, depression and anxiety, and the ability to undertake the normal activities of daily life, which patients complete before and after treatment.12
In a recent systematic review of 24 unique knee instruments, the psychometric evidence of patient-reported outcome measures for the knee was examined resulting in a recommendation to use the KOOS, Cincinnati Knee Rating System and Lysholm Knee Score to evaluate ACL injury.12 The International Knee Documentation Committee Score performs well as a measure of general knee function and is useful for describing the outcome following ACL reconstruction. It should however be pointed out that the patient's perspective after ACL injury can still be considered insufficiently knowledgeable.13 ,14
Personal reflection
It is likely that in the near future, all surgeons will be required to demonstrate objective measures of long-term outcome of ACL surgery. The patient's perspective should be the primary outcome.12 Patients should fill out the questionnaire, which should be valid concerning age, sex and activity level rather than knee pathology. Measures with a good responsiveness include the KOOS and Cincinnati Knee Rating System.
ACL surgery
Surgery or non-surgery management?
The main goal of ACL management is to restore normal function, reduce symptoms, improve quality of life and minimise the risk of complications. Experts agree that treatment strategy should be customised to address not just meniscal and articular cartilage but the associated ligament injuries as well.
Since the 1970s surgery has been the treatment most commonly recommended by orthopaedic surgeons. The question ‘surgery or non-surgery?’ has not really been studied in depth mainly because of the strong tradition to perform surgery and the difficulties in carrying out a level I study based on this research topic. Only three level I studies have addressed this question to date. The first two were both from Sweden, published in the 1980s.15 ,16 According to a Cochrane study17 the conclusions from these two studies had limitations because of their design and the fact that there is insufficient evidence to inform about current practice. Good quality randomised trials are required to remedy this. There is now a recent level I study available: ‘The Kanon Trial—A randomised trial on ACL injury. Results at 2 years—primary outcome’.18
This study included moderate and high activity level adults aged 18–35 years. The study did not include professional athletes or low activity level individuals. The results showed that ACL-reconstructed individuals in this study had primary outcome results evaluated with KOOS, Tegner activity scores and knee laxity at rest after 2 years that were similar to several other reports, which verifies that the surgery in this study was as well performed as in other studies.
In the conservatively treated group with rehabilitation 40% had discomfort and were operated on secondarily and subsequently reached the same results as the patients who were primary operated. The other 60% managed as well as the primary operated ones. Overall the study shows that in young active adults with an acute ACL tear, an early ACL reconstruction followed by structured rehabilitation provide no better outcome than early rehabilitation alone. The authors conclude that by starting with rehabilitation alone, approximately 60% of the ACL reconstructions can be avoided without compromising the results.
This study has aroused great interest around the world and as expected it is also hotly debated, as most surgeons believe that the ACL should be operated on in active people. Several editorials have discussed this level I randomised controlled trial (RCT) study. As an example an editorial in Arthroscopy19 can be mentioned: ‘We believe that, although the article should be carefully read, its conclusion should be rejected because the number of patients requiring meniscectomy was dramatically increased in the non-operative group. The authors do however make a legitimate point: not every patient with an ACL tear requires surgery’.
Personal comments
We should complement the authors for doing this excellent level I RCT study on a very timely and important topic. It is very demanding to carry out a RCT level I study such as this.
I agree with most surgeons that athletes and active persons with high knee functional demands including cutting motions need and should be offered surgery. However, the Kanon Trial shows that >50% of non-elite active people with an ACL injury can do well without surgery, at least in the short term. It should however also be pointed out that this study indicates that almost 50% may need surgery. The 5-year follow-up results from this study are about to be published and they are according to reports (personal message from Frobell RB, Roos EM, Roos HP, et al 2012) similar to the 2-year results. The patient-related outcomes show no difference between the groups and a survival analysis for meniscus injury will be presented.
After 35 years of involvement in clinical and academic work relating to ACL injuries, I believe that it is not necessary to operate on every patient who experiences an ACL rupture.
After 35 years of involvement in clinical and academic work relating to ACL injuries, I believe that it is not necessary to operate on every patient who experiences an ACL rupture. We should offer surgery to a specifically selected group of patients who we believe would benefit from surgery, including individuals active in cutting and jumping sports and other demanding activities, those who have meniscus and/or articular cartilage injury, recurrent giving way, etc. The choice of surgery or no surgery should be individualised after a careful and open discussion between the patient and the surgeon.
Timing of ACL surgery
During the 1970s up to beginning of the 1990s most ACL surgeries were carried out during the first 2 weeks after the injury. More recently, surgeons have recommended delaying reconstruction for 3–6 weeks because of the risk of arthrofibrosis.20 This has been the conventional wisdom since then in spite of the fact that this conclusion was based on a level IV study with open bone-tendon-bone (BTB) technique with notchplasty and with a very limited retrospective material followed-up. The optimal time for surgery is now once again debated, as focus is shifting towards the importance of associated injuries such as meniscal and articular cartilage damage.
Facts from a cohort from the Norwegian ACL registry (n=3475) show that the odds of articular cartilage injury increase by 1% for every month delaying the surgery and that the odds for meniscus injury are twice as large if there is an articular cartilage injury and vice versa. A delay in the timing of ACL reconstruction from ≤6 months to >6 months following injury is associated with a significant increase in the prevalence of medial meniscus tears.21–23
Regaining knee kinematics after ACL surgery has previously been considered almost impossible. However, kinematics can be restored if reconstruction is carried out within 10 weeks as shown in a study using radiostereometric analysis.24
Personal comment
When evaluating these results it is important to realise that in spite of the fact that the registries as such are a major step forward in evaluating ACL surgeries, they do not really show what happens between the time of injury to the time of surgery as more controlled studies do.
Many experienced surgeons believe that an optimal time to perform ACL surgery is when knee motion has returned to normal and effusion no longer is present, which is often the case at 3–6 weeks after the trauma. This is still considered the optimal time for ACL surgery for most active people. Some less active patients with isolated ACL tears can choose to delay or choose not have surgery. Time will show how well they do. There is always an option for a delayed ACL reconstruction if needed, even if this may not be optimal considering the risk for additional injury. If this is the case a well controlled rehabilitation is essential.
Techniques of ACL surgery: double or single bundle?
During the last few years some experts have strongly advocated the use of double bundle (DB) ACL reconstruction, as it has been shown to improve the control of knee rotation in a laboratory setting.25 A DB ACL reconstruction is however not synonymous with an anatomic ACL reconstruction. A single bundle (SB) ACL reconstruction placed at the centre of the femoral and tibial insertion sites can restore anteroposterior and rotational laxity as well as a DB reconstruction.26 This implies, that well performed DB or a SB ACL reconstructions can both result in an anatomic ACL reconstruction.
Personal reflection
An anatomic ACL reconstruction should be the goal, whether it is DB or SB. Innovations such as DB ACL reconstruction technique must always be supported, especially as a DB ACL reconstruction is most likely of some benefit for the knee biomechanics.
The interest in doing DB ACL reconstructions is declining in Sweden. This may be due to the ability to do an anatomic ACL reconstruction successfully by going back to basics by restoring the original anatomy with a SB ACL reconstruction.27
I still believe in the following principles: firstly, the choice of surgery should be individualised to match the patient's knee morphology and anatomy as well as the patient's demands and wishes. Secondly, during the surgery the surgeon should try to replicate the native anatomy as much as possible and use a technique with which he/she is very familiar.
Who should do the ACL surgery?
A DB ACL reconstruction is a rather technically demanding surgical procedure and should therefore probably not be performed by everybody. A total of 85% of ACL surgeons do fewer than 10 ACL reconstructions/year.28 The term ‘the occasional ACL surgeon’ has been coined. The question ‘should occasional ACL surgeons carry out DB ACL reconstructions?’ has been raised. Most agree that the ACL DB surgeon should preferably be very experienced in ACL surgery!
Personal reflections
In regular ACL surgery there are many technical pitfalls, and from a technical point of view an ACL reconstruction can sometimes be a very difficult surgery. Using multiple tunnels such as in a DB ACL reconstruction will result in a more complex surgery. I believe that ACL surgery is often more difficult than, for example, total joint reconstructive surgery as there are so many surgical evaluations and decisions the ACL surgeon needs to make. The ACL surgeon also needs to be experienced enough to be able to bail out of a technique if something fails, and be aware of different techniques.
Nowadays, I believe that it is not the choice of graft or technique that is the key for success. It is the often the choice of surgeon!
Nowadays, I believe that it is not the choice of graft or technique that is the key for success. It is the often the choice of surgeon!
Return to sport
During the 1990s speedy return to sport became popular based on a few level IV case series articles that advocated return to sports between 4–6 months after ACL surgery.29 Return to top-level football/soccer is a major risk factor for knee arthritis after an ACL injury.30 In 2011, Harald Roos told me (personal communication) that evidence-based evaluations do not prove a 3–6 months return to sports is safe and efficacious due to the fact that biological healing is not complete.
A recent paper shows that the best football (soccer) players in the world, that is, those participating in Union of European Football Associations (UEFA) Champions League, need 7 months to return to first training, 10 months to return to regular training and 12 months to return to match play.31 See table 1.
Anterior cruciate ligament reconstruction and times from diagnosis to return to match play
A meta analysis of 48 studies shows that overall, 82% of participants had returned to some kind of sports participation after ACL surgery, 63% had returned to their preinjury level of participation and 44% to competitive sport at final follow-up.32 Patients aged > 25 years are less likely to return to their preinjury level than younger patients.
A systematic review of the last 10 years of publications found only 35 studies (13%) that had noted objective criteria required for return to athletics.33 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). The results of this systematic review showed a major lack of objective assessment before release to unrestricted sports activities. Furthermore, commonly used muscle functional tests are not demanding or sensitive enough to identify differences between injured and non-injured sides.34
Personal reflections
The results of Waldén's study highlighting the 12-month time period to return to sport in Champions League players who ruptured their ACLs can guide patients who are returning to cutting sports.31 The best elite football (soccer) players need a year to get back to full match play in spite of the fact that they are (mostly) treated by the very best surgeons and are subjected to state-of-the-art daily rehabilitation.
When discussing return to sport, this mostly involves top athletes. It is prudent to remember that top-level athletes may well have exceptional neuromuscular skills and will therefore be reasonably well prepared to meet the demands of safe return to sport. It is however, the clumsy or unskilled player who returns to a low level of sport who may be at greater risk of reinjury than well-trained, highly athletic individuals.
When the ACL injury is isolated and there is no meniscus tear or articular cartilage injury, careful return to sport may start earlier. The decision to return to sport must be individualised after a careful follow-up evaluation. The present criteria for return to sport need to be revisited, especially as recurrent injury seems to be an increasing problem.
The decision to return to sport must be individualised after a careful follow-up evaluation. The present criteria for return to sport need to be revisited, especially as recurrent injury seems to be an increasing problem.
ACL tear and osteoarthritis
Osteoarthritis development in the injured joints is caused by intra-articular pathogenic processes initiated at the time of injury, combined with long-term changes in dynamic joint loading.35 After an ACL tear the loading pattern of the knee is altered and degeneration may develop. An ACL injury in combination with a meniscus tear substantially increases the risk of radiographic osteoarthritis.36 ,37 The meniscus has a key role in the structural progression of knee osteoarthritis and a tear is a risk factor for osteoarthritis. The type of tear is more important than the size of the resection.38 The risk of developing osteoarthritis is 14% to 26% with a normal medial meniscus, 37% with meniscectomy and 60% to 100% untreated ruptures. There is a lack of evidence to support a protective role of repair or reconstructive surgery of the ACL or meniscus against osteoarthritis development. An ACL reconstruction may not decrease the incidence of knee osteoarthritis.39 Non-operated ACL tears without associated meniscus tear show no or very limited osteoarthritis after 15 years.40
An important and well conducted meta-analysis showed that previously reported prevalence rates of knee osteoarthritis after ACL surgery may have been too high.41 In the highest-ranked studies the authors reported a low prevalence of knee osteoarthritis for individuals with isolated ACL injury (0% to 13%) and a higher prevalence for subjects with combined injuries (21% to 48%). Participation in top-level sport is also a risk factor. All top athletes have degenerative changes by 35 years and 42% had undergone total knee replacement.42
There are clinically relevant differences in the response of the knee to meniscus tears on the basis of patient age and sex.43 Elevated expression levels of arthritis-related markers indicate an increased catabolic response in patients under 40 years old. Higher expression of catabolic markers in patients with meniscus and ACL tears suggests that this combined injury pattern is more likely to lead to the development of osteoarthritis. Catabolic activity in meniscus tissue may predict patients who are at risk for progression of osteoarthritis following partial meniscectomy.
It is important to be aware that the development of osteoarthritis is caused by intra-articular pathogenic processes initiated at the time of injury, combined with long-term changes in dynamic joint loading. The variation in outcome is reinforced by additional variables such as age, sex, genetics, obesity, muscle strength, activity and reinjury.44
Cartilage markers and MRI data indicate a sustained healing process of the knee articular cartilage continues for 1–2 years after the initial injury.45 ,46 Early return of large loads on the joint can be potentially disastrous.47
Personal reflection
The development of osteoarthritis after an ACL injury depends very much on the injury mechanism and concurrent meniscal injury. Operated cohorts have an increased risk for developing osteoarthritis, indicating that the surgical technique such as setting the graft tunnels correctly is most likely a vital factor. An interesting question is if the introduction of the DB technique will lower the incidence of osteoarthritis.
The evidence for sustained healing of knee articular cartilage for as long as 1–2 years after an ACL injury should make the surgeon and the rehabilitation team pay careful attention to the rehabilitation process and take account of this when deciding when it is time to return to sport.
The development of osteoarthritis after an ACL injury depends very much on the injury mechanism and concurrent meniscal injury.
Early activity modification, a well planned knee rehabilitation programme and specific neuromuscular rehabilitation should be considered. This should be supervised with expert guidance by an experienced physiotherapist. Dye's studies show that achieving joint homeostasis as evaluated by bone scan prior to return to activity may be essential, and can be seen as providing an alternative explanation for the conundrum of knee instability and pain.48
Long-term outcome of surgery for quality control
Taken together, ACL injuries represent a major medical burden. There are over 200 000 primary ACL reconstructions carried out per year in the US alone, making the procedure the 6th most common in orthopaedics in the US. I anticipate that there will soon be a requirement for all involved to report and analyse their patient outcomes after ACL treatment. It seems that it may well be increasingly important to create national or regional registries for ACL injury, such as the ones in the Scandinavian countries.3 ,27 This will be driven by the increasing focus on quality assurance in healthcare.
The results of ACL reconstruction have been reported extensively, mostly with very good results up to 90%. Unfortunately, most therapeutic studies have been in the form of case series with evaluation by the non-blinded surgeon.1 ,49 This provides only a low level of evidence. There is, however, a significant trend towards a higher mean level of evidence over time. It appears that the impact factor is a reliable tool for gauging the level of evidence of primary ACL reconstruction in journals.1
There are, however, alarming figures gradually emerging. The complication rate has been reported to be 10% to 30%. Unfortunately, an ACL reconstruction may fail, and the rates of either reinjuring an ACL-reconstructed knee or sustaining an ACL rupture to the contralateral knee range from 3% to 49%.50 Risk factors for repeat ACL injury include return to competitive side stepping, pivoting, or jumping sports and the contact mechanism of the index injury. Female patients are at no greater risk of repeat ACL injury and graft choice does not affect the rate of repeat ACL injury.51
In the scientific literature in English between 1995 and 2009, 39 RCTs evaluating the long-term outcome after ACL reconstruction were published. The results show no differences between the use the bone-patellar tendon-bone graft and the hamstring tendon graft or in clinical outcome, when comparing single-bundle and double-bundle ACL reconstruction.49
Personal reflections
Most orthopaedic surgeons are confident that they have good to excellent results after an ACL reconstruction. This feeling may be correct, but it is not really supported in recent well controlled studies or registries.
Most orthopaedic surgeons are confident that they have good to excellent results after an ACL reconstruction. This feeling may be correct, but it is not really supported in recent well controlled studies or registries.
However, this needs to be verified by following up the patients in some way. I do still believe that the surgeon should see his/her patients with ACL reconstruction down the line in order to personally know how well they are doing. It is especially important to see those patients that are not doing so well as they often have many questions and the surgeon can learn a lot from this group of patients. As mentioned above, some kind of follow-up is part of quality care and it is something that patients and healthcare authorities will definitely require more often in the future.
ACL injury prevention
There are now several studies showing success and good efficiency of ACL injury prevention programmes in football (soccer) and handball.52–55 The Swedish Football Association in cooperation with an Insurance company (Folksam) recently completed a large prevention study called the ‘Knee Control Programme’. In this study 500 teams with girl football players aged 11–17 years old participated; 50% were randomly chosen to use the ‘Knee Control Programme’, while the remaining 50% served as a controls. In total 341 teams with more than 4500 players completed the study. The results show that the players using the programme decrease the risk of an ACL injury by two-thirds and the risk of a serious knee injury by half.56
In a classic study of alpine skiers, two common mechanisms of ACL injury were identified from careful video analysis of knee injuries.57 This information was used to educate the on-slope staff from 20 ski areas, who participated in a training and education programme. A control group did not get this education and training. Serious knee sprains declined by 62% among trained patrollers and instructors compared with the two previous seasons, but no decline occurred in the control group.
In summary, it can be concluded that ACL prevention programmes are effective.58 ,59 Pooled estimates suggest a substantial beneficial effect of ACL injury prevention programmes, with a risk reduction of 52% in female athletes and 85% in male athletes.60 The individual coaching of the player by the sports physiotherapist and compliance with the training programme by the player are key factors in the rehabilitation process.61
There are many aspects that must be included and controlled for a programme to be successful. ACL injury prevention strategies should include two-feet landing instead of one foot, avoidance of excessive dynamic valgus of the knee upon landing and squatting and focusing on the ‘knee over toe position’.62 Hamstring, gluteus medius and hip abductor strength must be improved. ACL injury incidence can be influenced by teaching avoidance tactics, flexibility, strengthening, proprioception and agility. The programmes should be easy and not made too complex.
Personal reflections
ACL injury prevention programmes that work are now available in sports such as handball, basketball and football (soccer) as well as alpine skiing, providing that they are well planned. There is, however, a need for continuously improving these and creating successful and effective programmes for other sports.
The key issue for a prevention programme to be successful is proper implementation. Vital factors for success include the individual coaching of the player and well controlled compliance with the training programme.
The key issue for a prevention programme to be successful is proper implementation. Vital factors for success include the individual coaching of the player and well controlled compliance with the training programme. This is very important in team sports, where group programmes thereby can be effective. In some sports the solution will depend on customised programmes for individuals. The success of the preventive education programme in alpine skiing should be further studied and more widely implemented.
I support the message from my colleague and friend Tönu Saartok, of the Karolinska Institutet, Stockholm, Sweden, that ‘we should develop a zero tolerance concept for sports injury, like drunken driving, car accidents and doping’.
References
Footnotes
-
Competing interests PAR has committed his career to minimising the deleterious effect of ACL injuries in athletes through surgical and non-surgical methods. He has held research funding and industry sponsorship from a wide range of sources relating to surgery and rehabilitation products. He has received speaker honoraria and had travel/accommodation paid for at numerous international conferences to speak on various aspects of ACL injury addressed in this article.
-
Provenance and peer review Not commissioned; internally peer reviewed.
-
▸ References to this paper are available online at http://bjsm.bmjgroup.com