A new consensus statement, titled “Return to play after hamstring injuries in football (soccer): a worldwide Delphi procedure regarding definition, medical criteria and decision-making,” on return to play after hamstring injury for soccer athletes, published in the November 2017 issue of the British Journal of Sports Medicine, warns against relying on imaging findings like MRI results to make the decision on whether a soccer player is ready to return to the field.
Hamstring injuries are one of the most common injuries in soccer and unfortunately anywhere from 12% to 33% of athletes who experience one will have a recurrence within a year of the first injury and this injury will require more extensive rehabilitation than the initial injury and more time away from games and practices.
Despite this real risk of re-injury, differing definitions and methodologies in the management of hamstring injuries have prevented improvements in management of hamstring injuries and return to play (RTP) policies. That is, until now.
To achieve a consensus on three main questions, how should return to play be defined? Which medical criteria should be used to make the return to play decision? And who should make that decision?, Nick van der Horst, Ph.D. and colleagues in the Department of Rehabilitation, Physical Therapy Science and Sport at the University Medical Centre of Utrecht in the Netherlands, and colleagues conducted a study using the Delphi procedure.
Using data from a systematic review of definitions and criteria for return to play after hamstring injury to create the questionnaires, the researchers conducted four Delphi rounds with 58 hamstring injury experts who were chosen from 28 International Federation of Association Football (FIFA) Medical Centers of Excellence from around the world.
The experts chosen hold a diverse range of positions in clinical practice and research including full professor, medical director, sports physician, orthopedic surgeon, clinical researcher, performance coach and athletic trainer. And most of them have written multiple international publications and have an average of 15.8 (SD ±8.2; range: 3-35) years of practical experience in the management of hamstring injury in soccer.
For each Delphi round, participants were sent an email with a link to the online questionnaire and were given six weeks to send it back. In order for a consensus to be reached, there needed to be an agreement amongst 70% or more of the experts. The four Delphi rounds were performed between July 2015 and July 2016, and included a questionnaire, analysis and an anonymous feedback report. Each round received a more than 83% response rate.
The following are key aspects of the consensus statement.
Defining Return to Play
In the first Delphi round, experts were asked to choose the proper terminology for returning to the game after injury and most selected either “return to play” or “return to competition.” In Delphi round 2, a consensus was achieved on adopting return to play—including its acronym RTP—as the proper terminology.
Next a consensus was also achieved on the actual definition of return to play, with the experts defining it as “the moment a player has received criteria-based medical clearance and is mentally ready for full availability for match selection and/or full training.”
Criteria for Return to Play
Another important area addressed by the consensus statement was the medical criteria used to make a decision about return to play. Experts agreed that the criteria should include medical staff clearance, absence of pain on palpation, absence of pain during strength and flexibility testing, absence of pain during/after functional testing, absence of pain during/after functional performance, similar hamstring flexibility, performance on field testing, and psychological readiness.
The experts also recommended that performance on field testing include repeated Sprint Ability test, deceleration drills, single leg bridge, position specific global positioning system (GPS)-targeted match specific rehabilitation.
According to available data, athletes with localized discomfort on palpitation just after RTP following hamstring injury were four times (Adjusted Odds Ratio (AOR): 3.95; 95% CI: 1.38 to 11.37) more likely to sustain a re-injury than athletes without discomfort on palpation. Research has also shown a connection between fear of re-injury and unsuccessful RTP, indicating a need for psychological readiness to be included in RTP guidelines.
The consensus statement states that the hamstring flexibility should be assessed using both the active and passive straight leg raise test and that “’similar hamstring flexibility’ could involve a 0% to 10% difference between injured and uninjured leg or compared with preinjury data.”
A player’s mental attitude is also suggested as an important return to play criteria because a positive mental attitude not only reduces anxiety and stress, but also improves performance and reduces the risk for re-injury.
On the flip side, the RTP criteria that the experts agreed should be excluded from the decision making process include:
- Neuromuscular function
- MRI
- Completion of a number of full friendly matches
- Completion of a number of full training sessions
Unfortunately, no consensus could be reached on whether “similar eccentric hamstring strength” should be included or excluded from the criteria.
The authors wrote, “The expert panel remained divided, with two irreconcilable opinions: one group of experts stated that similar eccentric strength assessment is important as a criterion for RTP as the eccentric phase is also the contraction mode in which injury occurs, and strength asymmetries should be eliminated because they can increase the risk of injury.”
“The other group of experts stated that strength measurements are not functional, asymmetries are normal, and that too many factors influence the measurement of strength, so that reliable measurements are not possible.”
Due to a lack of consensus, “similar eccentric hamstring strength” was listed as a potential criterion to support the RTP decision instead.
When it came to who has the authority to clear an athlete for return to play, the experts agreed that the decision-making process should be shared between the athlete, sports physician, physiotherapist, fitness trainer and team coach, primarily through consultation.
According to the authors of the consensus statement, “Although not yet studied and validated in clinical practice, this Delphi study may help clinicians faced with the problem of when an athlete should RTP after a hamstring injury. Furthermore, both the definition and criteria can be used in research, potentially leading to greater uniformity and promoting comparability of research.”
They added, “There is a need for high-quality prospective research to validate RTP criteria. Considering the multidimensional nature of hamstring injuries, RTP criteria should not be validated as univariate factors, but interaction between criteria as well as the varying weighting of criteria due to time and circumstances needs to be considered.”
Best Interest of Athlete
In an interview with OTW, van der Horst, said one of the most important takeaways from the consensus statement was that when it comes to return to play criteria, the focus needs to be on the results of performance tests not on imaging findings.
The other important takeaway was that the RTP decision needs to be a multidisciplinary decision. He said, “The RTP decision is always a risk assessment of the upcoming event (World Cup final or friendly game) and the risk of re-injury. Many stakeholders (athlete, medical team, performance team, coach, etc.) are involved and ultimately the risk threshold needs to be discussed with the best interest of the athlete always as a primary focus.”
He also described the challenges with creating the consensus statement, saying, “The biggest challenges in gathering data were to make sure we had a high-quality expert panel. Ultimately, we succeeded thanks to the support from the FIFA Medical Centers of Excellence and lots of the ‘top-guns’ in hamstring injury management were included.”
Another challenge he said “was the data collection, as this was a worldwide Delphi procedure. Close contact with the experts and of course digital media ensured an excellent response to our questionnaires.”
To view the full consensus statement, click here.
