Study Spotlight: Clinical Exam and Intramuscular Tendon Involvement in Hamstring Injuries

By: Joel Luedke

Hamstring injuries are the most common non-contact soft tissue injuries that are likely to be suffered by an athletic population.  They are not hard to evaluate but in order to determine the true severity of the injury and if it involves the intramuscular tendon can be tricky.  This Study Spotlight takes a look at that very process, identifying tendon involvement based on the clinical examination.  Check out what they found.

What They Did: 

Researchers in this study set out to take a look at if by using flexibility and strength testing if we are able to determine if intramuscular tendon involvement is present in a hamstring injury.  They wanted to know if we are able to gather this information could it be used in better classification of injury severity on clinical exam.  They did this by measuring flexibility, strength and comparing to diagnosis via MRI.

What They Found:

Of the 74 acute hamstring injuries they evaluated, 52 (70.3%) of the injuries affected the myotendinous junction.  These 52 injuries showed increased deficits in flexibility and decrease mean strength when tested at 15deg of knee flexion compared to the injuries without intramuscular tendon discontinuity.  They also found that flexibility and strength showed major overlap and variance among injuries with and without intramuscular tendon involvement.

What It All Means:

While it is not surprising there was differences when it comes to the flexibility and strength with these more severe hamstring injuries the results show that it is still almost impossible to differentiate the extent of severity with clinical tests alone.  This can make it hard to determine 'proper' return to play timelines due to the fact that you can't really tell intramuscular tendon involvement on clinical exam.

The frequency as which they found intramuscular involvement, 70.3% I think is extremely telling that this might be more common than I previously expected.  While there are on 74 in the study the fact that the percentage is that high will be something we keep in mind as we treat hamstring injuries and look at return to play guidelines.

Limitations

I think the researchers did a good job in listing their limitations with the major one is not being able to know where the subjects were at strength or flexibility wise prior to the injury (as they weren't intentionally injured as part of the study).  This could play a role in how the subjects responded post injury but something that isn't able to be controlled for.

Resource: Can a Clinical Examination Demonstrate Intramuscular Tendon Involvement in Acute Hamstring Injuries?