This article is the first part of a series on disorders of the foot and ankle. Surgeons from the University of North Carolina Department of Orthopedic Surgery provide an update in this sports medicine topic. The specific focus is on peroneal tendon problems causing ankle pain and dysfunction.
The peroneal tendon is divided into two parts: the peroneus longus and the peroneus brevis. It is located on the lateral (outside) of the lower leg and ankle. The two sections start together at the upper portion of the lower leg and travel down the length of the lower leg. Both parts of the tendon wrap around under the ankle bone and then separate again and attache to two separate places on the foot.
Peroneal tendon injuries can occur as a result of misalignment of the ankle, frequent (repeated) ankle sprains, or overuse in athletic activities. It’s not a common problem. So, treatment isn’t based on evidence from large scientific studies. Instead, surgeons rely on what’s referred to as a consensus approach. This means they listen to what the experts have to say and see how others treat it as reported in published case studies.
Several specific conditions affecting the peroneal tendon are presented. The authors describe and discuss peroneal tendinopathy, os peroneum syndrome, peroneal tendon dislocation, and peroneal tendon tears. A special section is included for each one called the Author’s Preferred Treatment to help guide other surgeons treating any of these problems.
Tendinopathy refers to any inflammation of the tendon or the sheath (the covering) around the tendon. Dancers, runners, and athletes with chronic ankle instability from repeated ankle sprains are the people most likely to develop this problem. Os peroneum syndrome is a very painful condition caused by fracture of the os peroneum, ruptured tendons around the os peroneum, or entrapment of the os peroneum or peroneus tendon. The os peroneum is an extra little piece of cartilage or bone that is located within the peroneus longus tendon.
Treatment for both peroneal tendinopathies and painful os peroneum syndrome (POPS) begins with conservative (nonoperative) care. Antiinflammatories, shoe (heel) wedges, and physical therapy are the first approaches in care. In some cases of severe pain associated with acute injury, the patient may be put in a short-leg cast (below the knee, including the foot and ankle) or controlled ankle motion (CAM) boot.
Surgery is an alternate treatment option but only after the patient has tried three to six months of conservative care. For patients with tendinopathy, the surgeon uses an open incision to inspect the tendon and tendon sheath. The sheath is cut open and the tendon repaired. The surgeon leaves the tendon sheath unrepaired to prevent further pressure on the tendon.
In the case of a painful os peroneum syndrome, the bone or cartilage fragment is surgically removed. The surgeon must be careful to remove the os peroneum without damaging the peroneal tendon. If the tendon has already been frayed, torn, or ruptured from rubbing against the os peroneum, then the surgeon removes the os peroneum and then repairs the tendon. With large tears of the peroneus longus, the surgeon may stitch it to the peroneus brevis to help hold it together.
Tendon dislocation occurs most often during a forceful injury or in patients who have a very shallow groove for the tendon to travel around the ankle bone. The diagnosis of an acute peroneal tendon dislocation can be confirmed by the presence of the fleck sign on X-rays. This is a gap or space seen on the film indicating at least a partial disruption of the tendon. MRIs and ultrasound studies are used to look for fractures and to assess the shape and depth of the groove holding the tendon in place.
Conservative care can be tried but surgery is usually needed for tendon dislocations. This is especially true for athletes who want to get back into action as soon as possible. The authors describe several operative procedures they use to treat peroneal tendon dislocations (or subluxation, which is a partial dislocation). They provide color photos taken during surgery to help demonstrate their operative techniques.
And, finally, the treatment of peroneal tendon tears is presented. Mechanical trauma and high shear stress contribute to this type of injury. If the injury is forceful enough to rupture the tendon, there is often damage to other soft tissue structures in the same area. Treatment depends on all the structures involved and the severity of the injuries.
For example,patients with less than 50 per cent of the tendon torn can try the same nonoperative care described for tendinopathies. Surgical repair is advised if conservative care fails to reduce pain, improve function, and/or restore ankle stability. Surgery is also recommended when more than 50 per cent of the tendon is torn (or it is fully ruptured). If the tendon can be repaired, the surgeon will clear away any frayed edges and complete the repair. A tendon graft or tendon transfer may be needed to reconstruct more severe tears or ruptures.
Without enough evidence to create clinical treatment guidelines, reviews such as these authors provide are very helpful. Surgeon experience and published case reports support the need to identify the underlying cause of the injury. It’s important to correct any anatomical abnormality present to ensure a successful result.