The vast majority of peroneal tendinosis will heal without surgery. This is because it is an overuse injury and can heal with rest. If there is significant pain, a CAM Walker boot for several weeks is a good idea. If there really is no tenderness with walking, an ankle brace might be the next best step. Patients should very much limit how much they are walking or on their feet until the pain abates. This usually takes several weeks. Resumption of training can then occur, but must occur very slowly and be based on pain. For those patients who have hindfoot varus, as noted above, an orthotic that tilts the ankle to the opposite side may well help to offload the tendons. It is important to talk to your doctor about changing your training. This includes using new shoes for running or also cross-training, which means alternating activities each day. Physical therapy is also very important. This, as with ankle sprains, can be done to strengthen the tendons.
There is some interest at the moment in using platelet-rich plasma (PRP) to help stimulate healing growth. Currently, there are no studies showing that this works for the peroneal tendons. Steroids are probably best avoided as they can actually damage tendon. Surgical treatment is indicated if the pain does not get better with rest. Conservative treatment - that is, without surgery - should last, however, even up to a year before considering surgery. If there is a tear, meaning a split that runs along the length of the tendons, one could consider cleaning it out and repairing the tendon. Sometimes, making the groove in the back of the bone of the fibula deeper allows the tendons more space and can help as well. Finally, if the tendon is very bad, one may need to resect the tendon and connect both the longus and brevis together. Only the specific tendon involved should be addressed. Occasionally, both may be involved.