The peroneal tendons are 2 tendons (peroneus longus and brevis) that run along the outside edge of your ankle. The peroneus brevis tendon inserts on the base of the 5th metatarsal while the peroneus longus travels underneath the foot. Peroneal teninopathy or tendinosis implies the tendons have become dysfunctional and thickened, like a frayed rope.
Tendinosis is caused by overuse when the body cannot adapt to meet demands placed on it. Overuse can be precipitated by muscle imbalance, improper footware, improper technique in sport, poor biomechanics, etc. Certain systemic conditions such as rheumatoid arthritis can predispose someone to tendinopathy or tenosynovitis (inflammation of the tendon sheath).
As with any tendinopathy, pain and decreased performance are the major symptoms. At early stages, the pain may initially improve with activity, worsen towards the end, and cause soreness that night or the next day. There may be subjective and objective strength loss. Pain will typically occur in a distribution that follows the tendon.
Procedural options for chronic tendon dysfunction include regenerative-type injections (such as platelet-rich plasma) that can theoretically provide long lasting pain relief and improved function by stimulating the body’s own natural healing response. There is some evidence that needling the tendon alone can stimulate bloodflow and healing. A procedure called TENEX can be done under ultrasound as well which uses a small oscillating needle to debride (suck out) the damaged parts of the tendon.