A number of processes can affect tendons.
Tears and myxoid degeneration
Tears are common and are categorised as:
- complete or incomplete (partial)
- full thickness or partial thickenss
- horizontal or longitudinal (split)
- hypertrophic or atrophic (more serious)
The MRI characteristics are of change in shape of the tendon (thickened, thinned) as well as increase in signal on both T1WI and T2WI. Unfortunately these features are indistinguishable from myxoid degeneration.
Prediposing factors to tendon rupture
- chronic use / overuse
- acute trauma
- diabetes mellitus
- rheumatoid arthritis and other inflammatory arthropathies.
- chronic renal impairment
- steroid use
Should only be called if fluid is seen surrounding the entire tendon. A mesotendon may be seen as a thin low intensity band. If the tendon communicates with a joint, such as the long head of biceps at the shoulder, and flexor hallucis longus at the ankle, then no fluid should be present in the joint to make the call.
If the fluid is loculated the term stenosing tenosynovitis can be applied. This is most commonly seen in
Dislocation or subluxation of tendons
- extensor carpi ulnaris (medial)
- long head of biceps (medial +/- into joint if subscapularis torn)
- peroneal tendons (lateral or medial)
- tibialis posterior (medial and anterior)