Clinical findings just after return to play predict
hamstring re-injury, but baseline MRI findings do not

De Vos RJ, Reurink G, Goudswaard GJ,
Moen MH, Weir A, Tol JL. Br J Sports Med.
ePub 18 July 2014.

Take Home Message: Key
predictors of hamstring re-injury are higher number of previous hamstring
injuries, more degrees of active knee extension deficit, isometric knee flexion
force deficit at 15°, and the presence of localized discomfort on posterior thigh
palpation just after return to play (RTP).

are no specific guidelines regarding return to play (RTP) after a hamstring
injury. Despite using imaging techniques and agility and stabilization
exercises for treatment, re-injury rates remain a problem and increase the
rehabilitation period. De Vos and colleagues investigated the association
between clinical and imaging findings at baseline and clinical tests performed
after RTP to identify factors associated with re-injury following initial
hamstring injury. Eighty participants (age 18-50 years) were diagnosed with a
hamstring injury by one of six sports medicine physicians using both clinical evaluation
and magnetic resonance imaging (MRI) performed within 5 days of initial injury.
As part of the procedures, all participants completed a rehabilitation program
consisting of progressive agility and trunk stabilization exercises. The
clinical tests performed during initial diagnosis were also performed just
after RTP. These tests included hamstring flexibility, strength testing, and
muscle palpation. Participants reported possible hamstring re-injuries to the
study team and the lead investigator conducted a phone interview to confirm the
presence of a hamstring re-injury. The study team also asked the participants
about any possible re-injuries at a 6-month and 12-month follow-up visit. Sixty-four
of the eighty participants were included in the final analysis; 17 (27%) reported
a hamstring re-injury that occurred at a median 100 days after RTP. Four
specific factors were associated with re-injury, including 1) the number of
previous hamstring injuries (33% increased risk per number of previous
hamstring injury), 2) degrees of active knee extension deficit (13% increased
risk per degree), 3) isometric knee flexion force deficit at 15° (4% increased risk per measure of
force in Newtons), and 4) the presence of localized discomfort on posterior
thigh palpation just after RTP. The MRI findings showed 89% of clinically recovered
hamstring injuries had increased intramuscular signal intensity, but the re-injury
rate was too small to discriminate the findings as a predictor for re-injury.
In conclusion, the weak association of MRI results after RTP emphasizes that
clinical and functional tests are better predictors of hamstring re-injury than
an MRI just after RTP.

findings combined with a history of previous hamstring injuries were
significant predictors of re-injury of the hamstring within one year after the
athlete returned to play. Hamstring strains take time to heal so the
rehabilitation process must be carefully observed. Functional testing may be the
best way to determine if the hamstring is healed and if there is a chance of
reoccurrence. Functional testing may be the better and safer route to predict
re-injury of a hamstring strain over MRIs. Key predictors of hamstring
re-injury were decreased isometric knee flexion, decreased knee extension, and
tenderness with palpation of the hamstring muscles after return to play. The
baseline MRIs of the hamstring injury showed no significance in predicting
re-injury of the hamstring once the participant returned to play. If the re-injury
predictors in this study are implemented to clinical practice, athletes that
demonstrate the positive functional or clinical findings once they RTP may be more
likely to suffer subsequent injury. The findings of this study can also help to
identify rehabilitation and injury prevention strategies for hamstring
re-injury, by addressing the deficits reported in this study. Hence, we need to
keep sure we monitor the 3 key risk factors that we can modify (active knee
extension deficit, isometric knee flexion force deficit, and localized
tenderness), incorporate reducing these into our treatment goals, and reassess
them prior to RTP.

Questions for Discussion: What are examples of different rehabilitation programs that might
focus more on the recovery of the clinical findings that are associated with
re-injury? What kind of training programs can be utilized by high-risk athletes
to prevent hamstring re-injury?

by: Samantha Sisson, Grace Brooks
by: Kim Pritchard


De Vos, R., Reurink, G., Goudswaard, G., Moen, M., Weir, A., & Tol, J. (2014). Clinical findings just after return to play predict hamstring re-injury, but baseline MRI findings do not British Journal of Sports Medicine, 48 (18), 1377-1384 DOI: 10.1136/bjsports-2014-093737