Diagnostic accuracy of clinical tests for assessment of hamstring injury: a systematic review

The prevalence of hamstring injuries is very high each year in the athletic population.  Hamstring injuries are also among some of the most debilitating soft tissue injuries for athletes during their seasons.  Currently, the diagnosis of hamstring injuries is determined through a combination of different tools such as palpation, swelling, skin integrity, and resisted testing, along with diagnostic imaging.  

This systematic review sought to determine which specific orthopaedic special tests are clinically relevant for hamstring injuries, as well as their diagnostic accuracy.  In this review, the authors noted: "MRI and US are considered the criterion reference standards for diagnosis of hamstring injuries.  However, both MRI and US are not practical alternatives for diagnosis of hamstring injuries..."  

The criteria used for this systematic review had to meet all of the following: 1. patients presented with hamstring or posterior thigh pain, 2. a cohort, case-control, or cross sectional design used, 3. the study included at least 1 clinical examination test to evaluate hamstring pathology, 4. the results of the clinical test were compared against an acceptable reference standard (MRI or US), 5. the study reported diagnostic accuracy of measures (SN, SP, +LR, -LR), and 6. the study was published in English. 

Following the search the authors found only 3 studies that met their inclusion criteria (notably the SN and SP).  Study #1 by Cacchio et al, used: Puranen-Orava test, Bent-knee stretch test, and Modified bent-knee stretch test.  Study #2 by Zeren and Oztekin, used: Taking off the shoe test, AROM test, PROM test, and Resisted ROM test.  Study #3 by Schneider-Kolsky et al, used a composite clinical assessment.  

Unfortunately, the results were all over the place.  The major confounding variable was the acuteness of the injury, which varied in all 3 of the inclusion studies.  Table 3 in the article does a nice job summarizing the diagnostic accuracy of all 3 studies.  The authors concluded that "caution should be used when utilizing orthopaedic special tests for diagnosis of hamstring injury, as diagnostic accuracy of these tests is not well established."  

Overall, I think what we need to consider with this systematic review is that a comprehensive examination is still the most effective tool we have as clinicians in the assessment of hamstring injuries.  While special tests have a place in diagnosis of hamstring injuries, they are not at this time clinically relevant enough to use alone in determining hamstring injury.  It will be interesting to see more evidence come out in the future, as hamstring injuries in the athletic population are very common.  

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