Validation of a New Device for Measuring Isolated Gastrocnemius Contracture and Evaluation of the Reliability of the Silfverskiöld Test.

BACKGROUND: Important aspects on the diagnostics of isolated gastrocnemius contractures (IGCs) have been poorly described. This study was designed to validate a new ankle range of motion (ROM) measuring device for diagnosing an IGC. In addition, we wanted to investigate the reliability of the clinical Silfverskiöld test.

METHODS: Twelve health care personnel (24 feet) were examined by 4 testers on 3 different occasions for the reliability testing of the new ankle ROM measuring device. The same participants were examined using the Silfverskiöld test to examine the reliability of the clinical test. Eleven patients (15 feet) with IGC were examined before gastrocnemius recession, immediately after surgery, and 3 months after surgery to examine the validity and responsiveness of the ankle ROM device.

RESULTS: An intraclass correlation coefficient (ICC) >0.85 was found for both inter- and intrarater reliability for the new ankle ROM device. The device confirmed an IGC in 13 of 15 feet before surgery and 3 of 13 feet at 3-month follow-up. At baseline, the measured ankle dorsiflexion was median 3 degrees with the knee in extension, which increased to 10 degrees ( P < .001) immediately after surgery and 12 degrees ( P = .003) at 3-month follow-up. ICC values of 0.230 to 0.791 were observed for the inter- and intrarater reliability testing of the clinical Silfverskiöld test.

CONCLUSION: The new ankle ROM measuring device was reliable and responsive for detecting IGC. The Silfverskiöld test had poor inter- and intrarater reliability. Level of evidence Level II, prospective cohort study.