You are in: eMedicine Specialties > Orthopedic Surgery > FOOT AND ANKLE Pes CavusArticle Last Updated: Dec 20, 2007AUTHOR AND EDITOR INFORMATIONAuthor: Norman S Turner, MD, Assistant Professor, Department of Orthopedic Surgery, Mayo Clinic School of Medicine Norman S Turner is a member of the following medical societies: Alpha Omega Alpha, American Academy of Orthopaedic Surgeons, American Medical Association, American Orthopaedic Foot and Ankle Society, Mid-America Orthopaedic Association, and Minnesota Medical Association Editors: Heidi M Stephens, MD, Associate Professor, Department of Surgery, Division of Orthopedic Surgery, Director of Diabetic Foot Clinic, Assistant Dean for Clinical Outreach, University of South Florida College of Medicine; Courtesy Joint Associate Professor, Department of Environmental and Occupational Health, University of South Florida College of Public Health; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Shepard R Hurwitz, MD, Director of Clinical Services, Department of Orthopedic Surgery, University of Virginia School of Medicine; Director, Division of Foot and Ankle Surgery, Department of Orthopedic Surgery, University of Virginia Health System; Dinesh Patel, MD, FACS, Associate Clinical Professor of Orthopedic Surgery, Harvard Medical School; Chief of Arthroscopic Surgery, Department of Orthopedic Surgery, Massachusetts General Hospital; Jason H Calhoun, MD, FAAOS, Chairman, J Vernon Luck Distinguished Professor, Department of Orthopedic Surgery, University of Missouri Author and Editor Disclosure Synonyms and related keywords: high arch, cavus foot, cock-up deformity, clawtoe deformity, foot pain, talipes cavus, contracted foot, exaggerated arch INTRODUCTIONPes cavus is a high arch of the foot that does not flatten with weight bearing. No specific radiographic definition of pes cavus exists. The deformity can be located in the forefoot, midfoot, hindfoot, or a combination of these sites.1 ProblemThe spectrum of associated deformities observed with pes cavus includes clawing of the toes, posterior hindfoot deformity (described as an increased calcaneal angle), contracture of the plantar fascia, and cock-up deformity of the great toe. This can cause increased weight bearing for the metatarsal heads and associated metatarsalgia and calluses. EtiologyThe etiology of pes cavus can be identified approximately 80% of the time. The causes include malunion of calcaneal or talar fractures, burns, sequelae resulting from compartment syndrome, residual clubfoot, and neuromuscular disease. The remaining 20% of cases are idiopathic and nonprogressive. Identifying the etiology is essential to determine if the deformity is progressive, which assists in operative planning. Neuromuscular diseases, such as muscular dystrophy, Charcot-Marie-Tooth (CMT) disease,2, 3, 4, 5 spinal dysraphism, polyneuritis, intraspinal tumors, poliomyelitis, syringomyelia, Friedreich ataxia, cerebral palsy, and spinal cord tumors, can cause muscle imbalances that lead to elevated arches. A patient with a new-onset unilateral deformity but without a history of trauma must be evaluated for spinal tumors. Multiple theories have been proposed for the pathogenesis of pes cavus. Duchenne described intrinsic muscle imbalances causing an elevated arch. Other theories include the extrinsic muscle and a combination of the intrinsic and extrinsic muscles being causes of the imbalance. In 1992, Mann described the pathogenesis of pes cavus in patients with CMT disease.6 An understanding of the muscles involved and the sequence of the involvement helps in understanding the deformity. An agonist and antagonist model for the muscles determines the deformity. In CMT, the anterior tibialis muscle and the peroneus muscle develop weaknesses. Antagonist muscles, posterior tibialis and peroneus longus, pull harder than the other muscles, causing deformity. Specifically, the peroneus longus pulls harder than the weak anterior tibialis, causing plantarflexion of the first ray and forefoot valgus. The posterior tibialis pulls harder than the weak peroneus brevis, causing forefoot adduction. Intrinsic muscle develops contractures while the long extensor to the toes, recruited to assist in ankle dorsiflexion, causes cock-up or claw toe deformity. With the forefoot valgus and the hindfoot varus, increased stress is placed on the lateral ankle ligaments and instability can occur. In patients with polio, the deformity is in the hindfoot and is caused by weakness of the gastrocsoleus complex. This leads to a marked increase in the calcaneal pitch angle with normal forefoot alignment. PathophysiologyThe pathophysiology of the deformity is based on the etiology (see Etiology). ClinicalThe presentation for patients with pes cavus is quite variable, based largely on the extent of deformity. Patients can present with lateral foot pain from increased weight bearing on the lateral foot.7 Metatarsalgia is a frequent symptom, as is symptomatic intractable plantar keratosis. Ankle instability can be a presenting symptom, especially in patients with hindfoot varus and weak peroneus brevis muscles. Weakness and fatigue can be observed in patients with neuromuscular disease. The severity of the presenting symptoms is as variable as the symptoms themselves. Evaluation of a patient who presents with pes cavus begins with a thorough history and complete examination to determine the etiology. Patients with a unilateral deformity frequently have a history of major trauma. Neuromuscular disorders can be identified by family history. A new-onset unilateral deformity is highly suggestive of a spinal cord tumor and necessitates an appropriate workup. Examination begins with observation of the gait. Hindfoot positioning is evaluated through gait analysis looking for varus. During swing phase, foot positioning is analyzed, looking for anterior tibialis weakness and foot drop. Cock-up toes can be observed with recruitment of the extensor hallucis longus (EHL). The shoe should also be inspected for increased lateral wear. The range of motion of the ankle, subtalar, midfoot, and forefoot is examined. The deformity is determined to be flexible or rigid. The forefoot is observed for plantarflexion, and the hindfoot is observed for varus. Documenting the strength of the individual muscles is essential for determining surgical options. Agonist and antagonist muscle weakness must be carefully examined, especially in CMT disease. The Coleman block test determines if the subtalar joint is flexible. The test is performed by having a patient stand with a 1-inch wood block under the heel and lateral foot. This allows the first ray to be plantar-flexed off the block. If the hindfoot corrects to a neutral position, the deformity is flexible. If the hindfoot does not correct, the deformity is rigid. A neurologic examination is required, specifically including detailed muscle strength testing. Sensory examination reveals deficits that can be observed in CMT disease. For more information about pes cavus, see the eMedicine article Charcot-Marie-Tooth Disease. INDICATIONSThe goal of treatment is to produce a plantigrade foot that allows even distribution of weight. Failure to maintain an asymptomatic plantar grade foot is an indication for surgery. RELEVANT ANATOMYThe relevant anatomy depends on the etiology of the deformity and the procedure performed (see Surgical therapy). CONTRAINDICATIONSAn absolute contraindication to surgery is poor vascularity. Revascularization should be performed prior to reconstruction if warranted. Ideally, the soft tissues around the ankle and foot should be intact, without excessive swelling or ulceration. If an ulcer is present, the wound should be healed before reconstruction in order to minimize infection risk. WORKUPImaging Studies
Other Tests
TREATMENTMedical therapyThe goal of treatment is to allow the patient to ambulate without symptoms. The underlying cause must be identified in order to determine if the disorder is progressive. The patient must understand the rationale for treatment and that surgical reconstruction does not provide a normal foot. The goal of surgery is to produce a plantigrade foot and pain relief. Repeat surgical procedures may be necessary, especially if the deformity is progressive. Preoperative patient education is essential for patient satisfaction. Nonoperative treatment may provide patients with significant relief. Physical therapy to stretch tight muscles and strengthen weak muscles may provide early relief. Orthotics with extra-depth shoes to offload bony prominences and prevent rubbing of the toes may improve symptoms. For varus deformities, a lateral wedge sole modification can improve function. Bracing for supple deformities or foot drop may allow patients to ambulate; however, in patients with sensation deficits, Plastazote linings in the brace are required and frequent inspection of the skin for ulceration is warranted.8, 9 Surgical therapySurgical decision-making requires a careful and complete examination of the foot and ankle, especially for rigidity, strength, and deformities.10, 11, 12 The goal of surgery is to provide a plantigrade foot. Surgical procedures can be broadly categorized into soft-tissue and bony procedures. No single procedure is appropriate for all patients, and frequently, multiple individual procedures need to be performed. Tendon transfers and osteotomies can provide correction of the deformity without requiring an arthrodesis; however, arthrodesis may be warranted if arthritic changes are observed in the joints or if complete muscle paralysis is present. The most common procedures are discussed below. Plantar fascia release In pes cavus, the plantar fascia may become contracted. Plantar fascia release is usually combined with a tendon transfer, an osteotomy, or both. This is frequently the first step in improving the deformity. Techniques for stripping the fascia off the calcaneus and complete resection of the plantar fascia have been described. The technique as described by Mann in 1993 is as follows13:
The complications of plantar fascia release include incomplete release and nerve injury. Great toe Jones procedure A great toe Jones procedure is performed for a cock-up deformity of the great toe with associated weakness of the anterior tibialis muscle.14 In this case, the EHL has been recruited to assist in ankle dorsiflexion, which causes hyperextension at the MTP joint and hyperflexion at the interphalangeal (IP) joint. This procedure transfers the EHL to the neck of the first metatarsal, with arthrodesis of the IP joint to improve the dorsiflexion of the ankle and remove the deforming force at the MTP joint. The technique is performed as follows:
The complication most commonly observed with this procedure is nonunion of the IP joint, which is often asymptomatic. Extensor shift procedure The extensor shift procedure involves transferring the EHL and the extensor digitorum longus (EDL) to the first, third, and fifth metatarsals. The technique includes completion of the Jones procedure, with incisions in the second and fourth web space. The tendons are harvested. The second and third tendons are transferred through a drill hole on the third metatarsal, and the fourth and fifth tendons are transferred to the fifth metatarsal. Girdlestone-Taylor transfer The Girdlestone-Taylor transfer procedure is used for flexible claw toe deformities. The deforming force of the flexor digitorum longus tendon is transferred to the extensors to correct the deformity. The technique is performed as follows:
Base of the first metatarsal osteotomy In patients with a fixed plantar-flexed first ray, a base of the metatarsal closing wedge osteotomy corrects the deformity, which is especially observed in CMT disease. This procedure is usually combined with a plantar fascia release in a mild deformity or a Jones procedure.14, 15 The technique is performed as follows:
Midfoot osteotomy Tarsal osteotomy has been described for deformities through the midfoot; however, these osteotomies require cutting through multiple joints. They are quite technically complex and are rarely performed.16 Peroneus longus to peroneus brevis tenodesis In patients with CMT disease who have a weak peroneus brevis (PB) and a preserved peroneus longus (PL), a tenodesis can be performed to help stabilize the ankle. This is frequently combined with a calcaneal osteotomy. The technique is performed as follows:
Calcaneal osteotomy Patients with hindfoot involvement usually require a calcaneal osteotomy to correct the deformity. The osteotomy can include a closing wedge, a vertical displacement, or a combination (triplanar osteotomy). This procedure is usually combined with a plantar fascia release and, frequently, a tendon transfer. The technique is performed as follows:
Beak triple arthrodesis The Siffert beak triple arthrodesis corrects pes cavus deformities through wedge resection and a triple arthrodesis.17 This procedure is used for treatment of rigid fixed deformities in adults. The technique involves mortising the navicular into the head of the talus and depressing the navicular, cuboid, and cuneiforms to improve forefoot cavus deformities. This procedure is complex and technically demanding. The technique is performed as follows:
Follow-upFollow-up care is based upon the procedure that has been performed and is listed after each procedure in Surgical therapy. COMPLICATIONSThe complications of these procedures include nonunion, malunion, infection, undercorrection, overcorrection, recurrence of the deformity, progression of the deformity, nerve injury, and continued pain. For progressive disorders, deformities can recur; patients need to be educated about this possibility before the initial surgery. OUTCOME AND PROGNOSISThe results of surgical intervention are difficult to compare because of the multiple possible combinations of procedures necessary for successful treatment. Also, patients have varying degrees of deformity, disease progression, and underlying etiology, making comparison virtually impossible; however, some positive findings have been reported, such as Wetmore and Drennan's report that 24% of patients with CMT disease who underwent a triple arthrodesis had satisfactory results at an average of 21 years of follow-up.18 They recommended the triple arthrodesis as a salvage procedure. Mann and Hsu reported on Roper and Tibrewal reported the results of soft-tissue procedures combined with osteotomies.19 Ten cases of CMT disease were reviewed 14 years after surgery. Two patients required repeat surgery secondary to recurrent deformity. At last follow-up, all patients had plantigrade feet, without requiring a triple arthrodesis. Gould discussed Limitations to the literature exist. Most of the reported results include reviews of adolescents and not of adults. Multiple variables are included with a small population of patients; however, the current trends are toward soft-tissue procedures combined with osteotomies. Arthrodesis is reserved for salvage procedures. FUTURE AND CONTROVERSIESThe current controversy in the reconstruction of these deformities is whether to proceed with osteotomies and tendon transfers or arthrodesis. The current trend is to preserve the joints, if possible, and perform an extensive arthrodesis as a salvage procedure. FURTHER READINGVisit Medical Interventions Effectively Treat Overuse Injuries in Adult Endurance Athletes at Medscape for more on pes cavus. MULTIMEDIA
REFERENCES
Article Last Updated: Dec 20, 2007 | |||||||||||||||||||