Is Peroneal Spastic Flatfoot Causing Chronic Ankle Pain?

Author(s): 
By Mark A. Caselli, DPM

A 14-year-old male athlete comes into your office with a chief complaint of ankle pain. He says he had the pain right after a soccer match. His parents and coach concluded that he had sprained his ankle. However, despite treatment, which consisted of rest, ice and the use of an Ace wrap, the patient’s pain continued for two months. He has pain in his ankle when standing and walking, and is not able to run or return to play.
Upon further questioning, you find out that neither his foot nor his ankle were ever swollen or ecchymotic, and he cannot recall an exact instance of twisting his ankle.

This is the most common presenting scenario of a patient with a peroneal spastic flatfoot and until this condition is considered as a potential diagnosis, this young athlete will find himself going from doctor to doctor continually being treated for an ankle sprain.
The patient with peroneal spastic flatfoot complains of pain, chronic ankle sprains and flatfoot. Pain occurs in the subtalar or midtarsal area of the involved foot. It usually occurs after some unusual activity or minor trauma and is aggravated by walking, prolonged standing, jumping or participating in athletics. Rest relieves the pain. In severe cases, you may see an antalgic gait and the patient may have a significant limp.
Upon examining those who have peroneal spastic flatfoot, you’ll usually find a stiff foot and often there will be decreased motion of the subtalar joint. Clinically, you may notice a loss of the longitudinal arch, limited subtalar motion, hindfoot valgus and forefoot abduction. Forced inversion of the foot will exacerbate the symptoms.

Is A Tarsal Coalition The Culprit?
Tarsal coalitions are the most common cause of peroneal spastic flatfoot. These coalitions may be either congenital or acquired and may have a genetic predisposition. Trauma, infection, arthritis and neoplasms can cause acquired coalitions, which are less common in pediatric patients than adults. The true incidence of tarsal coalition is unknown. Current reports consider it to be less than 1 percent.
The most prevalent coalitions are calcaneonavicular, talonavicular and talocalcaneal. Among these, calcaneonavicular coalitions appear to predominate. The coalition may be completely osseous (i.e., synostosis) or the bones may be divided by a fissure of varying depth, consisting of cartilage (i.e., synchondrosis) or fibrous tissue (i.e., syndesmosis).
Tarsal coalitions may occur bilaterally or unilaterally. Talonavicular fusions are usually present in both feet. Calcaneonavicular coalitions are bilateral in 60 percent of patients and talocalcaneal coalitions are bilateral in 50 percent. In infancy and early childhood, the condition is usually asymptomatic and is seldom recognized. Symptoms of the calcaneonavicular coalition usually appear between 8 and 12 years of age and those of the talocalcaneal coalition occur during adolescence. The talonavicular coalitions often remain asymptomatic.
Even though coalitions are the most likely cause of peroneal spastic flatfoot, they are not the only causative factor. It is recognized that any inflammatory pain surrounding the ankle or subtalar joint can result in this condition. Other etiologies of peroneal spastic flatfoot may include tuberculosis, osteomyelitis, trauma, osteoarthritis, rheumatoid arthritis, Sudeck’s atrophy (reflex sympathetic dystrophy), nonspecific tarsal synovitis, osteochondral fractures, osteoid osteoma, postoperative subtalar arthrodesis and synovial irritation created by altered biomechanics of the foot.

Essential Diagnostic Pointers
When attempting to pinpoint the etiology of peroneal spastic flatfoot, radiographic modalities remain the most beneficial diagnostic tools. Plain film radiography should be your initial screening tool for any young patient who has a rigid or semirigid foot, especially when you suspect tarsal coalition. The radiographic appearance of tarsal coalition depends on its site and whether it is bony or fibrocartilagenous. Be sure to include dorsoplantar, lateral and oblique projections among your initial radiographs. These reveal coalitions between the talus and navicular, and between the calcaneus and the cuboid.
For calcaneonavicular coalitions, the best view is a 45-degree oblique view of the foot made with the patient standing and the X-ray projected through the middle of the foot from the lateral to the medial side.
Getting an axial view of the calcaneus is necessary to reveal a talocalcaneal coalition. However, because it is often difficult to get a good axial view, the CT scan is the standard for radiographic diagnosis of the talocalcaneal coalition. Beaking on the dorsal and lateral aspect of the head of the talus adjacent to the talonavicular joint is a common secondary change in tarsal coalition. This talar beak appears to be produced by the impingement of the dorsal part of the navicular on the head of the talus during dorsiflexion.
Regardless of the precipitating factor, most authors agree that the peroneal muscles contract or shorten as a protective mechanism to reduce or eradicate pain. The musculature splints the subtalar and ankle joints against discomfort or pain, maintaining an everted attitude of the rearfoot. This splinting results in an adaptive, functional shortening with tautness or contracture of the involved muscles. The peroneus brevis muscle is most often implicated but the peroneus longus, peroneus tertius and the extensor digitorum longus muscles may also exhibit contracture in peroneal spastic flatfoot.

What To Consider For Treatment
When you see a young athlete with peroneal spastic flatfoot, it very important to clearly define treatment goals with both the athlete and parents, since the eventual return to full sports activity may not be attainable, especially if certain tarsal coalitions are involved. The progression of the treatment program should be as follows:
1) eliminate pain;
2) enable the youth to return to school and participate in all non-athletic school functions;
3) limited participation in athletic school functions, such as physical education classes; and
4) return to previous sports activities.
To facilitate initial symptomatic relief in a young patient, you may recommend rest, nonsteroidal antiinflammatory drugs, muscle relaxants, paraffin baths, heat, warm soaks and whirlpool.
With further conservative treatment, you want to decrease the motion of the painful joints in order to help alleviate pain. When a patient has moderate to severe pain on ambulation, using a below-the-knee cast is recommended for three to four weeks. You can combine this with a common peroneal nerve block and an injection of steroid and anesthetic into the sinus tarsi, which are effective in both relieving pain and muscle spasm.
Upon removing the cast, you should place the patient in orthotic devices and modified shoes that increase the support to the medial side of the foot.
Using a leather laminate foot orthosis with a deep heel seat and high medial and lateral flanges is recommended. This type of device offers good support but will deform to allow for foot pressure areas. Be aware that patients with peroneal spastic flatfoot usually cannot tolerate hard, rigid orthoses. You can modify shoes with 1/8- to 3/16-inch inner heel and inner sole wedges. You should also consider physical therapy for ankle strengthening exercises, range of motion exercises to increase inversion and other techniques to decrease pain.
Between 30 and 90 percent of patients have been reported to respond to nonoperative conservative treatment of tarsal coalitions. Most authors believe in exhausting or at least trying conservative care before any surgical intervention, although there are some that stress the importance of surgery as soon as possible.

What About Surgical Solutions?
Surgical treatment varies depending on the type of coalition present. The current recommendation for a calcaneonavicular bar is surgical resection of the coalition and interposition of fat, muscle or another inert material. This procedure is best reserved for children under the age of 14, who demonstrate no arthritic changes. In cases in which resection fails and a coalition reforms, or when you see degenerative changes in the tarsus, triple arthrodesis is used as a salvage procedure.
The surgical management of talocalcaneal coalitions remains controversial. Some authors say the degenerative changes in the talocalcaneal coalition are often present at the time of the initial diagnosis. In addition, resecting these bars often requires you to surgically excise the medial facet of the talocalcaneal joint, which results in considerable stress to the anterior and posterior facets.
Some believe this procedure leads to further degenerative arthritis. For this reason, many authors promote triple arthrodesis as an initial treatment. However, this operation severely restricts athletic potential and should be reserved for salvage when other approaches have failed.

Dr. Caselli (pictured) is Vice-President of the greater New York Regional Chapter of the American College of Sports Medicine and is a Professor in the Department of Orthopedic Sciences at the New York College of Podiatric Medicine.




References:

1. Brage ME, Larken J. Ankle, hindfoot, and midfoot injuries. In Reider B (ed) Sports Medicine: The School Age Athlete. Philadelphia, WB Saunders Company, 1996. pp 403-438

2. Caselli MA, Sobel E, McHall KA. Pediatric manifestations of musculoskeletal disease in children. Clin Podiatr Med Surg 15(3), 1998.

3. Donahoe BK, Kuhnell KA, Strenk ML. Rehabilitation of congenital and developmental conditions in children. In Sammarco GJ (ed) Rehabilitation of the Foot and Ankle. St. Louis, Mosby, 1995. pp 173-187.

4. Glockenberg A, Weinreb A, Pevny J. Rheumatoid arthritis-induced peroneal spastic flatfoot. J Am Podiatr Med Assoc 1987, 77: 185-187.

5. Lowy LJ. Pediatric peroneal spastic flatfoot in the absence of coalition, a suggested protocol. J Am Podiatr Med Assoc 1998, 88: 181-191.

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