The Cavus Foot in Athletes: Fundamentals of Examination and Treatment Sarang N. Desai, DO, Randolph Grierson, DO, and Arthur Manoli, II, MD Athletes with cavus feet present unique challenges to the orthopedic surgeon. Continuous high impact activity with this foot deformity leads to distinct injuries. Immediate recognition of the athlete’s cavus feet and associated injuries allows prompt treatment and return to sport. If not recognized, treatment will often fail. Injuries include stress fractures, ankle instablility, impingement syndromes, and tendon disorders. Appropriate treatment requires correction of the cavus deformity as well as the specific associated injuries. Nonoperative treatment includes specialized orthotic shoe inserts. If a course of nonoperative treatment fails, operative intervention is warranted. Operative treatment of the cavus deformity may include a simple dorsiflexion first ray osteotomy or more complex reconstruction, including a lateralizing calcaneal osteotomy. Correction or accommodation of the deformity as well as the identification of the specific injury will likely lead to successful treatment and return to a high level of competition. Oper Tech Sports Med 18:27-33 © 2010 Elsevier Inc. All rights reserved. KEYWORDS cavus, cavovarus, ankle instability, “peek-a-boo” heel

T

he cavus foot has been an enigmatic subject for many years. The belief that cavovarus feet are the result of neurologic lesions is deeply ingrained in the adult and pediatric orthopedic literature. Several potential causes of this deformity have been described. Many of these do include neurologic conditions such as polio, Charcot–Marie–Tooth disease, Fredreich’s ataxia, and cerebral palsy. Other common causes include the residual effects of clubfeet and compartmental syndrome. Despite the popular belief that cavus feet are a result of neurologic conditions, the single largest population remains idiopathic. From our clinical observation, these adult cavus feet are idiopathic, and often have a genetic component. Cavus foot deformities are common in athletes. These types of feet present unique injuries and challenges to the orthopedic surgeon. The deformity and associated injuries should be recognized and treated appropriately. The true incidence of cavus feet is unknown and multiple factors contribute to this. While in residency, pediatric orthopedic training involves treating children with sequela of neurologic disease. Many of these patients have severe cavovarus deformities. This has led to the notion that cavovarus

Michigan International Foot and Ankle Center, St Joseph Mercy Hospital, Pontiac, MI. Address reprint requests to Sarang N Desai, DO, Associated Orthopaedics and Sports Medicine, 4031 W. Plano Parkway, Plano, TX 75093. E-mail: [email protected]

1060-1872/10/$-see front matter © 2010 Elsevier Inc. All rights reserved. doi:10.1053/j.otsm.2009.10.002

feet are more common to children, and only occur in patients with neurologic disease. The result is cavus feet being deleted from the adult differential diagnosis. Another contributing factor is that most orthopedic surgeons have been taught the “too-many toes” sign as an easy way to diagnose a posterior tibial tendon deficient foot.1 The “peek-a-boo” sign is a similar easily performed test that diagnosis the cavus foot.2 This is a more recent discovery and is often not taught while in orthopedic training. Also, cavus feet are often bilateral, and therefore lack a normal foot for comparison. This can also make diagnosis more difficult.

Evaluation The “peek-a-boo” sign was described in 1993 in an article describing lower extremity contractures.2 We have used this test for 15 years and have found it highly sensitive for identifying the subtle cavus foot. This test is performed with the patient standing, with the feet aligned straight. These patients generally have tight Achilles, and therefore have a tendency to point their feet outward. We encourage the patients to look down at their feet to ensure their feet point straight ahead. When viewed from the front, the varus heel will be visualized medially in a cavus foot (Figs. 1 and 2). A foot with physiologic heel valgus would not display this characteristic. The amount of heel visualized medially should be compared with the contralateral limb. Two causes of a false positive “peek27

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S.N. Desai, R. Grierson, and A. Manoli II

Figure 1 Anterior standing examination shows bilateral “peek a boo” heels and prominent first metatarsal head fat pads.

a-boo” sign include a very large heel pad and significant metatarsus adductus. Heel varus should be confirmed with posterior examination. When visualizing from the front, a “bulging” first metatarsal head fat pad may also be seen medially. After the identification of a varus heel, the Coleman block test should be performed.3 This will identify whether the subtalar joint is supple and will also assess whether a plantarflexed first ray is driving the heel varus. The Coleman block test is performed by asking the patient to stand on a wooden (or 1 in) block. The first ray is left off the block medially. If the heel “corrects” to physiological valgus, the varus hindfoot is supple and caused by a plantarflexed first ray.3 This is often referred to as forefoot driven hindfoot varus (Fig. 3). A strong contribution of the peroneus longus can also be identified using another technique. This involves placing one thumb under the first metatarsal head and the other thumb across the remaining metatarsal heads. The patient is then asked to plantarflex the foot into the examiner’s thumbs. With peroneus longus overdrive, there will be more

Figure 2 Posterior examination reveals hindfoot varus bilaterally.

Figure 3 Coleman block test reveals correction of hindfoot varus into anatomic heel valgus.

force felt under the first metatarsal head as compared with the lateral heads.4 Assessment of the Achilles mechanism is fundamental to cavus foot evaluation. Part of that assessment involves performing the Silverskiold test that will isolate gastrocnemius tightness from the rest of the triceps surae. When the ankle cannot be passively dorsiflexed to neutral with the knee extended, but can be passively dorsiflexed to 5° of dorsiflexion with the knee flexed, gastrocnemius tightness exists.5

Foot Morphology and Biomechanics A tight gastrocnemius and a plantarflexed first ray are central to cavus feet.6 The repercussions of a plantarflexed first ray can be significant. A plantarflexed position of the first metatarsal causes the medial aspect of the forefoot to strike the ground first. When this occurs, the heel is forced into a varus position to maintain a balanced three-point contact position with the ground. Because of this, the hindfoot is unable to reach maximal eversion. This in turn decreases the ability of the subtalar joint to absorb and dissipate energy. The forefoot and hindfoot, although initially flexible, can progress to stiff then rigid over time. The forefoot then becomes fixed in a pronated position and the hindfoot in a varus position. A tight gastrocnemius can also significantly contribute to the cavus posture. When the foot is in a planterflexed position, the peroneous longus is placed at a biomechanical advantage and the tibialis anterior at a disadvantage. With this relationship, the peroneous longus maintains the first ray in a plantarflexed position.7 This position of the first ray is at first flexible, but over time can become stiff, and then rigid.

The cavus foot in athletes

29 the normal talocalcaneal angle. The foot height measured from the top of the talar body to the floor will be greater in the cavus foot compared to a normal contralateral side on the lateral aspect.11 An AP radiograph of the feet will reveal forefoot supination (Fig. 5). Other useful radiographs may include internal oblique of the foot to evaluate for calcaneonavicular coalitions and metatarsal fractures. Computed tomography scans can identify subtalar coalitions and degenerative changes of the ankle and tarsometatarsal joints.

Associated Pathologies Figure 4 Standing lateral radiograph shows an increased distance between the inferior base of the fifth metatarsal and inferior medial cuneiform. A break in Meary’s line and a posterior positioned fibula is also noted.

Radiographic Evaluation At our institution, radiographs consist of standing anteroposterior (AP) of both ankles (same cassette), both feet (same cassette), and lateral views of each foot and ankle on the same cassette.8 There are multiple consistent radiographic abnormalities common to cavus feet that can be identified. The lateral view reveals a break in Meary’s line (axis of talus, medial cuneiform, and first metatarsal) as a result of the plantarflexed metatarsal. Also in the lateral view, one observes a high arch with an increased measured distance between the inferior medial cuneiform and inferior fifth metatarsal base.8,9 A posteriorly positioned fibula may be seen due to an externally rotated ankle axis, as well as a dorsiflexed calcaneus.10 Although the calcaneus is dorsiflexed, the Achilles can still be tight (Fig. 4). With examination of the standing AP ankle (or foot) radiograph, several features are consistent. There is a decrease in

There are many conditions associated with cavus feet that should be considered and treated appropriately. We often see these associated pathologies in athletes given the repetitive high-impact activity. These injuries can be debilitating and can cost an athlete a successful career if not treated promptly. Patients with cavus walk on the outer border of their feet and their plantarflexed first ray. In the forefoot, the patient may develop overload calluses under the first metatarsal head and fifth metatarsal head or base. This can lead to hallux sesmoiditis. Jones fractures of the fifth metatarsal and fourth metatarsal stress fractures are common (Figs. 6-8). Other common stress fractures are of the tibial or fibular shaft, navicular, and medial malleolus. These fractures can be elusive, and we have found bone scans to be helpful. More proximally, cavus feet are prone to peroneal tendon pathology. This may include tendonitis, subluxation, dislocation, and tears (Fig. 9). The peroneus brevis is more prone to injury compared to the peroneus longus. An os perineum may also fracture leading to increased pain.12 Other common symptomatic foot problems include a tight Achilles and tight plantar fascia.13,14 Ankle instability and recurrent ankle sprains in a patient with cavus feet must be carefully considered. Standard repairs or reconstructions of the lateral ligaments may fail with-

Figure 5 Standing AP radiograph of the feet showing metatarsal overlap due to hindfoot supination and relative forefoot pronation.

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Treatment An attempt to correct the apparent pathology without addressing the concordant foot deformity will often lead to failure in treatment. This is particularly frequently observed with lateral ligament reconstruction without correction of the cavovarus deformity. A trial of nonoperative treatment should be instituted upon diagnosis. This consists of a specific cavus foot orthotic as well as a gastroc stretching program. We demonstrate how to perform these gastroc stretching exercises to each athlete in the office. We recommend 20 repetitions 5 times a day for each extremity. Many athletes come to our office stating they have tried orthotics, without alleviation of their symptoms, and in fact that their symptoms were made worse. When the orthotic is inspected, it is seen to be an orthotic designed for a planovalgus foot. We prefer a specific orthotic that has a few key design features. First, there is a recess to allow for the plantarflexed first metatarsal head. This allows the possibility of at least partial correction of the hindfoot, as demonstrated by the Coleman block test. Even if the deformity is not flexible, the recess will accommodate the plantarflexed first ray, and therefore be more comfortable for the patient. Second, there is an elevated heel to allow for equinus. Other features include a forefoot wedge that accommodates the valgus forefoot and a reduced medial arch. We have found that an or-

Figure 6 (A) AP radiograph displaying cortical hypertrophy consistent with fibular stress fracture. (B) Bone scan with increased uptake at the site of the fibular stress fracture.

out correction of the varus heel and/or plantarflexed first ray. Long-standing cases of cavus feet and ankle instability may lead to varus ankle arthritis.15 Stress fractures of the medial malleolus and navicular are also common (Fig. 10). External rotation of the talus and tibia can also result in knee pathology. This posture of the lower extremity leads to excessive stress on the lateral structures of the knee. Patients may complain of pain along the lateral collateral ligament or iliotibial band.14,16,17 The varus strain may also result in medial compartment arthritis in long-standing cases. Many other conditions may exist and should be recognized in the comprehensive picture of the cavus foot (Table 1).

Figure 7 (A) Radiograph of fifth metatarsal stress fracture. (B) Radiograph of intramedullary screw fixation of stress fracture.

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Figure 9 Peroneal tears are common with cavus feet particularly tears of the peroneus brevis.

thoses that fits snuggly against the medial arch is not only painful for many athletes, but it does not allow for hindfoot correction. In our practice, 3 of 4 patients have improved symptoms with this orthoses. It would be reasonable to consider the use of such an orthoses in a symptomatic athlete with a cavus foot shape. Appropriate shoe wear is also imperative for these patients. The shoe should allow for the prominent midfoot. This is best done with a soft wide laced upper. A flared heel that is slightly higher than the forefoot will help provide inversion stability. A tight Achilles with subsequent extensor recruitment often causes clawed toes in these patients. An extra depth toe box will accommodate these contracted toes. Medial posting should be avoided. Cosmetic cutaways and air chambers weaken the shoe and can increase hindfoot instability and

Figure 8 (A) Subtle left cavus foot with visible “peek-a-boo” heel. (B) MRI confirming navicular stress fracture. (C) Radiograph displaying screw fixation of navicular stress fracture. Figure 10 Cavus foot with medial malleolus stress fracture.

S.N. Desai, R. Grierson, and A. Manoli II

32 Table 1 Musculoskeletal Conditions Associated with the Cavus Foot Associated Conditions Fractures Medial malleolus Tibia shaft Fibular Navicular Base of fourth metatarsal Jones fracture of fifth metatarsal Sesmoid Os peroneum Soft-tissue injuries Peroneal tears/dislocations Plantar fasciitis IT band frication syndrome Knee lateral collateral tears Ankle lateral ligament instability Subtalar instability Achilles tendonitis MTP synovitis Arthritis Varus ankle arthritis Medial compartment knee Midfoot Other Tight gastrocnemius muscle Sesmoid overload, AVN Exertional compartment syndrome Metatarsus adductus Calluses under first and fifth metatarsal heads Large peroneal tubercle Large distal fibula MTP, metatarsophalangeal; AVN, avascular necrosis; IT, iliotibial.

should therefore be avoided. A cushioned neutral running shoe is recommended. When a trial of conservative treatment fails, operative intervention should be considered. It is imperative to identify and correct all aspects of the cavovarus foot deformity. A careful examination should reveal a supple versus rigid deformity, which is paramount in the successful treatment of these patients. As mentioned previously, a contracted gastroc is almost universally found in the cavovarus foot. We prefer to treat this with a modified Vulpius type lengthening. A medial incision approximately 15 cm from the tip of the medial malleolus is created, and the sural nerve is first identified. The gastrocnemius tendon alone, and often the soleus fascia, is then lengthened in a pie-crust manner.18,19 In the case of peroneal overdrive with a flexible first ray, a peroneus longus to brevis transfer is performed at the peroneal tubercle. The distal stump of the longus is transferred to the brevis tendon to avoid formation of a dorsal bunion. To address the plantarflexed first metatarsal, which drives a cavus deformity, we prefer a dorsal closing wedge V-type osteotomy secured with a 4.0-mm screw, notching the dorsal cortex to prevent fracture.20,21 With a more pronounced forefoot pronation deformity, a V-type osteotomy of the second

and third metatarsals, and possibly the midfoot may be required. As highlighted earlier, the cavovarus foot generally progresses from a supple deformity to a rigid deformity over time. In instances when the varus heel does not correct with a Coleman block test, a lateralizing calcaneal osteotomy is performed along with a dorsiflexion osteotomy of the first metatarsal. An oblique incision is made through the midportion of the calcaneal tuberosity, and the osteotomy is done perpendicular to the axis of the tuberosity. Cuts created too far posterior will penetrate Haglund’s prominence and bursa, whereas those too far anterior may enter the subtalar joint. The heel is translated 5-10 mm medially and secured with 2 stacked 6.5-mm screws. With an advanced cavovarus deformity, the magnitude of the deformity can become significant and the tissue stiff. When this occurs, a triple arthrodesis is required. The articular cartilage of the calcaneocuboid, subtalar, and talonavicular joints are denuded, and they are secured with 6.5-mm lag screws. The heel must be placed into mild valgus, and the forefoot derotated through the Chopart joints from its initial pronated position.22 A common error is correcting heel varus without correcting the forefoot deformity. When the heel is moved into valgus the first ray planterflexion increases, and this must be addressed or the heel will move back into varus after surgery. As noted previously, many conditions may be associated with the cavovarus foot shape. Some of these conditions may require operative treatment. Fractures are treated with rigid internal fixation using solid screws, or excision for sesmoid, or os peroneum fractures. Jones fractures are common, and at our institution, we treat these with rigid internal fixation with or without bone grafting (Fig. 7). Recent literature has supported acute fixation of Jones fractures.23 We also prefer to treat stress fractures of the navicular with rigid internal fixation (Fig. 8). We believe aggressive treatment of these stress fractures provides a more favoerable biomechanical environment for the fracture to heal, and allows the athlete to return to athletic activity faster. Along with internal fixation, we also address the cavus through either conservative or operative means as discussed earlier. We often see athletes who have failed multiple operative procedures for these fractures. This can be devastating for the professional as well amateur athlete. The importance of correcting the cavus deformity cannot be overemphasized. Peroneal tendon tears, subluxation, or dislocation should be treated appropriately. An incision is made just posterior to the posterior border of the fibula at the distal aspect of the superior peroneal retinaculum. The retinaculum is opened at its fibular insertion. Longitudinal tears are repaired. An extensively degenerated peroneus longus tendon is transferred to the peroneus brevis. If a shallow or convex groove is identified, it is deepened. We prefer to do this by drilling multiple 2.0-mm holes in an oblong shape, and impacting this cortical bone. The superior peroneal retinaculum is repaired through 3 drill holes in the fibula, and 2 horizontal mattress stitches with a heavy nonabsorbable suture. In this way we achieve a

The cavus foot in athletes

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References

Figure 11 Illustration showing the dorsal talar osteophyte common with ankle impingement.

secure repair, and also are able to advance a lax retinaculum. If the patient has greater tenderness at the peroneal tubercle, the incision is centered distally over the tubercle. Tears are repaired, and a large peroneal tubercle is removed. With recurrent ankle sprains the lateral ligaments should be tightened with possible augmentation. We perform a modified Brostrum repair. After repairing the anterior talofibular ligament in a vest-over-pants fashion, we then augment the repair with a thick superficial layer of the inferior extensor retinaculum.23 Many of these patients also have associated ankle impingement. This often manifests as either anteromedial or anterolateral ankle pain. Anteromedially, an osteophyte off the anterior talus is frequently recognized (Fig. 11). This osteophyte can impinge on the tibia during dorsiflexion of the ankle.24 This lesion can be removed through a small medial arthrotomy. If identified, an associated “kissing lesion” on the tibia should also be removed. Anterolaterally, a hypertrophied band of the anterior inferior tibiofibular ligament may cause pain.25 Patients may complain of discomfort anterolaterally, often with a painful click caused by impingement on the talus.26 This hypertrophied band is resected through a small anterolateral arthrotomy. Midfoot arthritis is common with cavus feet. We initially treat these with a graphite plate shoe insert. This decreases the motion at the midfoot articulations and has been successful in relieving pain in our experience. Failed conservative treatment may require a midfoot arthrodesis. Varus ankle arthritis is common with the cavovarus foot. Tibiofibular or calcaneal osteotomies may be appropriate early with arthrodesis for advanced stages.15 If ankle arthroplasty is considered, the cavovarus deformity must be corrected first, or the prosthesis may tip into varus.27

1. Johnson KA, Strom DE: Tibialis posterior tendon dysfunction. Clin Orthop 239:196-206, 1989 2. Manoli A 2nd, Smith DG, Hansen ST Jr: Scarred muscle excision for the treatment of established ischemic contracture of the lower extremity. Clin Orthop 292:309-314, 1993 3. Coleman SS, Chestnut WJ: A simple test for hindfoot flexibility in the cavovarus foot. Clin Orthop 123:60-62, 1977 4. Bordelon RL: Practical guide to foot orthoses. J Musculoskel Med 6:7187, 1989 5. DiGiovanni CW, Kuo R, Tejwani N, et al: Isolated gastrocnemius tightness. J Bone Joint Surg Am 84:962-970, 2002 6. Mosca VS: The Cavus Foot. J Pediatr Orthop 21:423-424, 2001 7. Silver RL, de la Garza J, Rang M: The myth of muscle balance. A study of relative strengths and excursions of normal muscles about the foot and ankle. J Bone Joint Surg Br 67:432-437, 1985 8. Chada H, Pomeroy GC, Manoli A 2nd: Radiologic signs of unilateral pes planus. Foot Ankle Int 18:603-604, 1997 9. Faciszewski T, Burks RT, Manaster BJ: Subtle injuries of the Lisfranc joint. J Bone Joint Surg Am 72:1519-1522, 1990 10. Lloyd-Roberts GC, Swann M, Catterall A: Medial rotation osteotomy for severe residual deformity in clubfoot. A preliminary report on a new method of treatment. J Bone Joint Surg Br 56:37-43, 1974 11. Pomeroy GC, Manoli A 2nd: A new operative approach for flatfoot secondary to posterior tibial tendon insufficiency: A preliminary report. Foot Ankle Int 18:206-212, 1997 12. Brandes CB, Smith RW: Characterization of patients with primary peroneus longus tendinopathy: A review of twenty-two cases. Foot Ankle Int 21:462-468, 2000 13. Carlson RE, Fleming LL, Hutton WC: The biomechanical relationship between the tendoachilles, plantar fascia and metotarsophalangeal joint dorsiflexion angle. Foot Ankle Int 21:18-25, 2000 14. McKenzie DC, Clement DB, Taunton JE: Running shoes, orthotics, and injuries. Sports Med 2:334-347, 1985 15. Fortin PT, Guettler JH, Manoli A 2nd: Idiopathic cavovarus foot and lateral ankle instability: Recognition and treatment implications relating to ankle arthritis. Foot Ankle Int 23:1031-1037, 2002 16. Messier SP, Pittala KA: Etiologic factors associated with selected running injuries. Med Sci Sports Exerc 20:501-505, 1988 17. Renne JW: The iliotibial band friction syndrome. J Bone Joint Surg Am 57:1110-1111, 1975 18. Pinney SJ, Hansen ST, Sangeorzan BJ: The effect on ankle dorsiflexion of gastroc recession. Foot Ankle Int 23:26-29, 2002 19. Saraph V, Zwick EB, Uitz W, et al: The Baumann procedure for fixed flexion contracture of the gastrocsoleus in cerebral palsy. Evaluation of function of the ankle after multilevel Surgery. J Bone Joint Surg Br 82:535-540, 2000 20. Beals TC, Manoli A 2nd: The peek-a-boo heel sign in the evaluation of hind foot varus. Foot 6:205-206, 1996 21. Manoli A 2nd, Hansen ST Jr: Screw hole preparation in foot surgery. Foot Ankle 11:105-106, 1990 22. Manoli A 2nd, Beals TC, Hansen ST Jr: Technical factors in hindfoot arthrodesis. Instr Course Lect 46:347-356, 1997 23. Portland G, Kelikian A, Kodros S: Acute surgical management of Jones’ fractures. Foot Ankle Int 24:829-833, 2003 24. Harper M: Modification of the Gould modification of the Broström ankle repair. Foot Ankle Int 19:788, 1998 25. Mosier-La Clair SM, Monroe MT, Manoli A 2nd: Medial impingement syndrome of the anterior tibiotalar fascicle of the deltoid ligament on the talus. Foot Ankle Int 21:385-391, 2000 26. Basset FH 3rd, Gates HS 3rd, Billys JB, et al: Talar impingement by the anteroinferior tibiofibular ligament. A cause of chronic pain in the ankle after inversion sprain. J Bone Joint Surg Am 72:55-59, 1990 27. Alvine F: Varus tipping.Presented at the Advanced Total Ankle Arthroplasty Course, February, 2000, Rosemont, IL