What are the peroneal tendons?
The peroneal tendons consist of the peroneus longus and brevis which are located on the lateral side of your ankle and connect to the base of the 5th metatarsal and base of the 1st metatarsal/medial cuneiform. The function of the peroneus muscles and tendons are to evert/stabilize your ankle and plantar flex the 1st metatarsal.
How does your peroneal tendons get injured?
The peroneal tendons get longitudinal tears inside of the tendon, tendinopathy (thickening of the tendons), and develop tenosynovitis. The tendons develop this pathology from acute ankle injury most commonly from ankle sprains and from chronic overuse. People with high arched feet are at a higher risk for develop peroneal tendon injuries.
How to diagnose peroneal tendon tears ?
A weightbearing X-ray will be done and this will help confirm foot type, look for possible os peroneum, and look for a possible enlarge peroneal tubercle. Ultrasounds could be used to look for tendon tears, but often an MRI will be used to look for peroneal tendon pathology. A test question that often occurs with MRI and peroneal tendon pathology is the magic angle which is an MRI artifact that occurs at 54.74 degrees and can show false positive for for peroneal tendinopathy.
How to treat peroneal tendon tears?
Conservative treatment is always done with RICE, immobilzation, NSAIDs, oral steroids, physical therapy, custom orthotics, ankle brace, stem cell injections. If pain persists then surgery will often be done which will depend on the extent of the peroneal tendon tears and tendinopathy. Some surgeons will consider doing a tendonoscopy which can help confirm tendon tears and will allow the surgeon to do tendon debridement and removal of tenosynovitis. A general rule that people follow is <50% tears then tendon debridement/repair with tubularization is done and >50% tears then tenodesis. Sometimes if the peroneal tendons are beyond salvation then a tendon transfer or use of allograft is done. Often if the patient has high arched feet that will be addressed at the time of the tendon repair to prevent further future injury to the tendon after repair.