The Thessaly test is a clinical examination technique useful in the detection of meniscal tears.

Background

Meniscal tears are commonly the result of twisting injuries or degenerative change where patients experience medial or lateral joint line pain. MRI is the most commonly used non-invasive diagnostic tool for meniscal injuries however there are a number of orthopedic special tests that may raise the index of suspicion for meniscal tears with varying degrees of sensitivity and specificity.

Procedure

The Thessaly test is a dynamic clinical test. The examiner supports the patient by holding their outstretched hands as the patient stands flatfooted on the floor ¹:

• the patient then stands on single leg in full weight bearing on the side to be tested
• the non-test leg is flexed at the knee to remove all weight bearing surfaces
• the weight bearing knee is then placed in between 5 and 20 degrees of flexion
• the patient then rotates (or grinds) then their femur on the tibia three times internally and externally

The test is positive when the patient reports reproduction of symptoms, joint line tenderness, or catching/locking occurs.

Evidence

A prospective cohort study of 213 patients found that at 20 degrees of knee flexion, the Thessaly test was 89% sensitive and 97% specific for medial meniscus tears with a positive likelihood ratio of 26 ². For lateral meniscal tears, sensitivity was 92%, specificity was 96% and the positive likelihood ratio was 22 ².