The tarsal bones include the calcaneus, talus, navicular, and cuboid. Together these bones form the subtalar joint (STJ) and the midtarsal (MTJ) joint, and are extremely important in proper foot function. When they fail to function properly, they lead to further problems, such as hammered digits and bunions. Loss of necessary motion in these joints can arise from a coalition, or a union of two of these bones.

The most common coalition of the rearfoot is the calcaneal navicular, CN Bar. Along with other coalitions, this occurs developmentally. The restrictions it imposes on joints are often painful. Upon examination, the physician will put the STJ and the MTJ through range of motion exercises. If a coalition exists, the manipulation of the affected joint will cause the patient pain and produce little to no range of motion.

Although x-rays and examinations are necessary in diagnosing a tarsal coalition, patients who suffer from this condition typically experience pain on the outside and top of the foot (dorsolateral) while walking. The peronial tendons are taught in spasm, thus causing the foot to evert. Pain is palpable on the coalition. An injection of an anesthetic and a steroid into the painful area may give temporary relief. When the coalition becomes symptomatic, however, conservative measures usually fail. Surgery is then indicated.

Before surgery is performed, other joints must be examined to assess secondary arthritic changes. If these changes exist, then fusion of the STJ and MTJ is indicated. If no other arthritic changes are noticed, then resection of the union is performed. The muscle belly of the Extensor Digitorum Brevis is commonly transplanted into the area of resected tissue. Post-operatively, a posterior splint is applied to the foot and leg and range of motion exercises are encouraged. Walking as soon as possible after sufficient healing is encouraged. Doing so will result in an increased range of motion.

Other coalitions in the foot include talo calcaneal (mid facet), talo navicular (rare), and calcaneal cuboid (also rare). Resection of this union must be employed. Should this fail, then a triple arthrodesis or fusion of the rearfoot bones is needed. Patients need to be told of this in the pre-operative consult.

Dr. Graham has been in private practice in Effingham since 1989 and is on staff at St. Anthony's Memorial Hospital and Effingham Ambulatory Surgical Treatment Center. He is Board Certified by the American Board of Podiatric Surgery and American Board of Podiatric Orthopaedics and Primary Podiatric Medicine. Dr. Graham is a Fellow of the American College of Foot and Ankle Surgeons, the American College of Foot and Ankle Orthopaedics and Medicine, and American Professional Wound Care Association. He is also a member of the American Podiatric Medical Association and the Illinois Podiatric Medical Association.

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