MRI is unnecessary for diagnosing acute Achilles tendon ruptures: clinical diagnostic criteria

Achilles tendon ruptures are common in middle-aged athletes. Diagnosis is based on clinical examination or imaging. Although MRI is commonly used to document ruptures, there is no literature supporting its routine use and we wondered whether it was necessary.

We (1) determined the sensitivity of physical examination in diagnosing acute Achilles ruptures, (2) compared the sensitivity of physical examination with that of MRI, and (3) assessed care delays and impact attributable to MRI.

We retrospectively compared 66 patients with surgically confirmed acute Achilles ruptures and preoperative MRI with a control group of 66 patients without preoperative MRI. Clinical diagnostic criteria were an abnormal Thompson test, decreased resting tension, and palpable defect. Time to diagnosis and surgical procedures were compared with those of the control group.

All patients had all three clinical findings preoperatively and complete ruptures intraoperatively (sensitivity of 100%). MR images were read as complete tears in 60, partial in four, and inconclusive in two patients. It took a mean of 5.1 days to obtain MRI after the injury, 8.8 days for initial evaluation, and 12.4 days for surgical intervention. In the control group, initial evaluation occurred at 2.5 days and surgical intervention at 5.6 days after injury. Nineteen patients in the MRI group had additional procedures whereas none of the control group patients had additional procedures.

Physical examination findings were more sensitive than MRI. MRI is time consuming, expensive, and can lead to treatment delays. Clinicians should rely on the history and physical examination for accurate diagnosis and reserve MRI for ambiguous presentations and subacute or chronic injuries for preoperative planning.

Level II, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.