Peroneal
The peroneus brevis and peroneus longus tendons are located on the outer part of the ankle. Their major function is to evert the ankle. A patient may feel or hear a “pop” with complete rupture/tear of one or both of the tendon. Weakness is seen on examination. X-rays are negative for fracture and a MRI is indicated when the physician has a high suspicion of the complete tear. A MRI also rules out associated pathology such as ligament tears and osteochondral injuries .
It is recommended that peroneal tendon ruptures be surgically repaired in most patients. The ruptures are usually repairable, but in some cases, the tendon has severe degeneration and is not repairable. In such cases, the tendon is transferred or sown to the neighboring peroneal tendon creating a “super” tendon. For example, the peroneus longus may not be repairable and would be transferred to the peroneus brevis. It is an outpatient procedure under general or regional anesthesia. The patient will be placed in a nonremovable splint and will be nonweightbearing with crutches. At two weeks, the stitches are removed and the patient is placed in a removable boot. The patient is still on crutches for week three and four. Partial weight-bearing in the boot will begin at four weeks and physical therapy at six weeks. The patient transitions from the boot to a lighter brace as they become stronger over the next one month.
Peroneal tendons can also pop out of place. If the tendon only pops partially out of place, then this is called subluxation. If the tendon pops completely out of place, then this is called dislocation. A dislocation is easier to clinically diagnose than a subluxation. With a dislocation, patient usually reports a traumatic event such as during skiing and will hear or feel the tendon popping out of place. This usually indicates a tear of the superior peroneal retinaculum, which holds the tendons in place. X-rays are usually negative but can show small bony avulsion of the retinaculum. A MRI will show the tear of the retinaculum, evaluate the peroneal tendons for associated tearing and rule out other pathology such as ligament or cartilage. An ultrasound may be indicated with subluxation or more subtle cases. The benefit of an ultrasound is that the patient can move their ankle in a circle and the sonographer can evaluate the tendon through this range of motion.
Nonoperative treatment of peroneal tendon dislocation is rarely successful. As a result, surgery is indicated not only due to the symptoms but due to the damage of the tendon as it pops out of place. This can result in partial tearing to complete rupture of the tendon over time. The surgical procedure includes tightening/imbricating the retinaculum to prevent the tendons from dislocating. The peroneal tendons are located in a groove or tunnel on the back portion of the fibula. The surgery also usually involves deepening this groove. It is an outpatient procedure under general or regional anesthesia. The patient will be placed in a nonremovable splint and will be nonweightbearing with crutches. At two weeks, the stitches are removed and the patient is placed in a removable boot. The patient is still on crutches for week three and four. Partial weight-bearing in the boot will begin at four weeks and physical therapy at six weeks. The patient transitions from the boot to a lighter brace as they become stronger over the next one month.
The treatment of peroneal tendon subluxation depends upon the degree and frequency of symptoms. Often times, the patient may opt for the retinacular imbrication and groove deepening mentioned in the above paragraph. The risk of non-surgical treatment includes the tendon developing partial tearing or complete rupture as it partially pops out of place.
