1. Hamstring Injuries in a Premier League Football Team: MRI vs
Hamstring Injuries in a Premier League Football Team: MRI vs. Clinical Diagnosis
Introduction
Hamstring injury is the single most common injury in professional football(1). Better injury prognosis can assist the working relationship between medical staff and management, because it may mean the difference between victory and loss in the world of professional sport. MRI is commonly used to confirm diagnosis and provide an indication of lay-off time, although clinical judgment is more established and is always used to assess injury. There is little evidence in current literature to differentiate between the two.
Aims: To evaluate the use of MRI as a prognostic tool for lay-off after hamstring injuries in professional football players at Sunderland AFC (SAFC) and compare it to the clinical judgment of team healthcare professionals.
By David Eastwood, 5th year medical student at Newcastle University
When using Erkstrand’s grading system to compare the accuracy of MRI grading vs. clinical grading, it was found that clinical grading was more accurate in prediction of time out of action. MRI grading appeared to underestimate injuries; injuries assessed as low grade in fact led to more lay off days than predicted. Overall, most injuries (18/27) were given the same MRI and clinical grading, illustrating that there was only some variation between methods.
MRI
Both
2) Method
A retrospective study was carried out using the medical database of Sunderland AFC: a Premier League football club. I selected players that had a hamstring injury and also had an MRI scan. The earliest injury occurred on 7/03/2009, with the most recent injury occurring on the 16/02/2013.
I selected current first team players, ex first team players and ex reserve team players. I then found 'individual time-loss’, 'radiological findings on MRI’ and ‘clinical findings’ for each injury, in documentation by medical staff at SAFC. MRI findings were interpretated using a modified Peetron’s classification into four grades. More severe injuries were represented by the higher grades; grades 2 and 3 each represent clinical fibre disruption. An established system by Jan Ekstrand(2) predicts time, in days, out of full contact training and playing football matches, based on Peetron’s grades. I used these values to analyse the accuracy of MRI and of clinical grading.
Ekstrand Classification
Normal MRI / Grade 0: absence < 1 week
Grade 1: absence c 2 weeks
Grade 2: absence c 3 weeks
Grade 3: absence >8 weeks
Fig 3: Bar chart to show which modality of grading was more accurate in predicting lay off times, when compared with actual time out
Fig 1: The Erkstrand classification, based on Peetron’s grades.
4) Conclusion
MRI can be helpful in verifying the diagnosis of a hamstring injury and to prognosticate lay-off time.
Radiological grading is correlated with lay-off times after injury but is not superior to clinical grading. The data I collected does not support the view that there is a significant advantage of clinical over MRI grading in providing a prognosis of layoff time. (p value = 0.25, significance <0.05)
The accuracy of clinical grading at Sunderland AFC is down to the ability and training of staff. This could be highly variable when comparing between different clubs.
More than 60% of hamstring injuries seen were of radiological grade 0 or 1, meaning no signs of fibre disruption on MRI, but it is, in fact, these injuries that cause the majority of absence days.
3) Results
In total, 27 players had hamstring injuries, with all of them receiving an MRI scan and clinical assessment. In terms of MRI classification, 7% were grade 0 injuries, 56% grade 1, 37% of grade 2 and 0% of grade 3. Clinical judgment assessed 0.5% at grade 0, 63% grade 1, 26% grade 2 and 1% grade 3. Therefore, clinical grading given by medical professionals did not always concur with grading reported from MRI.
5) Limitations
Factors such as reinjury could have affected the number of lay off days
Small sample size (27 players)
Biased sample size (All selected players saw the same doctor for clinical assessment)
Acknowledgments: I would like to thank Dr. Glen Rae and the full medical team at SAFC
References:
1) R D Hawkins, M A Hulse, C Wilkinson, A Hodson, M Gibson
The association football medical research programme: an audit of injuries in professional football
BJSM 2001;35:43-47
2) Jan Ekstrand, Jeremiah C Healy, Markus Walden, et al. Hamstring muscle injuries in professional football: the correlation of MRI findings with return to play Br J Sports Med doi: /bjsports
Fig 4: Hamstring injuries are exceptionally common in football (1)
Fig 2: Bar chart to show the number of hamstring injuries and how they were graded by the two modalities.