Patients typically complain of the acute onset of calf pain during sport or other activity. The pain may be felt as though the patient had been struck on the calf. Most patients find it difficult to walk after an Achilles rupture and rising on the affected heel is usully difficult or impossible. However, the long flexors can be sufficient to allow rising on the heel and the ability to do this does not exclude an Achilles rupture. Misdiagnosis as an ankle sprain or other benign injury is quite common.
Both Maffulli (1998) and Ritche (2006) draw attention to the benefits of considering the results of clinical tests together. Indeed, Simmonds (1957) did so in his original paper. Maffulli's paper is a useful guide to the diagnostic tests and their accuracy.
There is tenderness over the tendon with swelling, and a gap can usually be palpated 2-6 cm abovethe insertion. Maffuli found the palpation fo the gap to be the least accurate test for Achilles rupture, with a sensitivity of 0.73 and specificity of 0.89
In the Simmonds (1957) or Thompson (1962) calf squeeze test, the patient kneels facing away from the examiner or lies prone. Squeezing the calf normally produces plantarflexion of the ankle. If the Achilles tendon is ruptured this does not occur. The Simmonds test had a sensitivity of 0.96 and specificity of 0.93 in Maffulli's study.
In the Matles test the patient lies prone and the knee is flexed to 90deg. Any dorsiflexion of the foot indicates a ruptured tendon. A similar test is the resting posture or "angle of dangle". The foot hangs free over the end of the examination couch in the prone position - if the tendon is ruptured it will lie in abnormal dorsiflexion. We find the difference easier to appreciatein the Matles test. This had a sensitivity of 0.88 and specificity of 0.85 in Maffulli's study, less accurate than the Simmonds test, but the two together absolutely predicted the presence or absence of a rupture.
Douglas (2009) reported two patients in whom the Simmonds test was abnormal in the presence of an isolated tear of the gastrocnemius portion of the tendon, with intact soleus. Repair of the gastrocnemius tear returned the test to normal.
The right calf is swollen and the outline of the gastrocnemius muscle lost. The "angle of dangle" is more dorsilfexed on the right and this is clearer on the Matles test (right)
O'Brien (1994) described a test in which a needle is inserted into the Achilles tendon just medial to the midline, 10cm above the insertion. The foot is then plantar and dorsiflexed. If the tendon distal to the needle is intact the needle bevel will move in the opposite direction to the foot, hinging on the skin. If the tendon is ruptured, the needle either will not move or will move slightly in the same direction as the foot, drawn by the skin. Maffulli found this too painful to do on awake patients; in a small group of anaesthetised patients the sensitivity was 0.80.
In the Copeland (1990) test a tourniquet is inflated around the calf and the ankle dorsiflexed. If the tendon is intact the pressure should rise 35-60mmHg. If the tendon is ruptured there will be little or no increase. Again, Maffulli found this painful in awake patients, with a relatively low sensitiity of 0.78.
Because of its descriptive, long-term nature, Maffulli's study does not provide data on reproducibility of the tests. It does confirm the Simmonds calf squeeze test as the most accurate, with the Matles (or "angle of dangle") tests as useful adjuncts.