Objective: The purpose of this study was to evaluate the frequency of oedema and fatty degeneration of the soleus and gastrocnemius muscles in patients with Achilles tendon abnormalities. Methods: Forty-five consecutive patients (mean 51years; range 14-84years) with achillodynia were examined with magnetic resonance (MR) images of the calf. The frequency of oedema and fatty degeneration in the soleus and gastrocnemius muscles was determined in patients with normal tendons, tendinopathy and in patients with a partial tear or a complete tear of the Achilles tendon. Results: Oedema was encountered in 35% (7/20) of the patients with tendinopathy (n = 20; range 13-81years), and in 47% (9/19) of the patients with partial tears or complete tears (n = 19; 28-78years). Fatty degeneration was encountered in 10% (2/20) of the patients with tendinopathy, and in 32% (6/19) of the patients with tears. The prevalence of fatty degeneration was significantly more common in patients with a partial or complete tear compared with the patients with a normal Achilles tendon (p = 0.032 and p = 0.021, respectively). Conclusion: Oedema and fatty degeneration of the soleus and gastrocnemius muscles are common in patients with Achilles tendon abnormalitie
