Henry Ford Macomb Orthopaedic Residency

Henry Ford Macomb Orthopaedic Residency Quiz 7 Answers

1. PREFERRED RESPONSE: 4

DISCUSSION: The dynamic forces acting to maintain the position of the proximal phalanx at the head of the metatarsal are a balance between the extensor digitorum longus and the weaker intrinsic muscles. With hyperextension at the metatarsophalangeal joint, the intrinsic muscles become less efficient as plantar flexors. Consequently, the hyperextension deformity progresses in the metatarsophalangeal joint as the opposition of the intrinsic muscles to the extensor tendon lessens. This is in contrast to the situation in the interphalangeal joints, where the stronger flexors overpower the weaker intrinsic muscles, which act as the extensors. This combination of events leads to hyperextension at the metatarsophalangeal joint and flexion deformities at the interphalangeal joints, resulting in claw toe.

REFERENCES: Mizel MS, Yodlowski ML: Disorders of the lesser metatarsophalangeal Joints. J Am Acad Orthop Surg 1995;3:166-173. Coughlin MJ, Mann RA: Surgery of the Foot and Ankle, ed. 7. St Louis, MO, Mosby, 1999, pp 325-328.

DISCUSSION: The Coleman block test is used to evaluate the effect of the forefoot on the rearfoot varus. If the deformity corrects with the block, then the hindfoot deformity is flexible and the varus position is secondary to the plantar flexed first ray or valgus position of the forefoot. A rearfoot orthotic will not correct the forefoot cause of the deformity. The patient still may need a lateralizing calcaneal osteotomy to realign the hindfoot.

REFERENCES: Younger AS, Hansen ST Jr: Adult cavovarus foot. J Am Acad Orthop Surg 2005;13:302- 315. Alexander IJ, Johnson KA: Assessment and management of pes cavus in Charcot-Marie-Tooth disease. Clin Orthop Relat Res 1989;246:273-281

DISCUSSION: Eccentric gastrocsoleus strengthening (especially with heavy loads) consistently has been shown to be superior in the management of Achilles tendinopathy. Decreases in pain and increases in strength have been demonstrated despite the frequently refractory nature of this condition.

REFERENCES: Richardson EG (ed): Orthopaedic Knowledge Update: Foot and Ankle 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2003, pp 91-102. Vora AM, Myerson MS, Oliva F, et al: Tendinopathy of the main body of the Achilles tendon. Foot Ankle Clin 2005;10:293-308.

DISCUSSION: A flexor digitorum longus transfer, while not as strong as the peroneals, improves the tendon balance and maintains hindfoot mobility. Subtalar fusion is a salvage procedure. Posterior tibial tendon transfer compromises inversion strength and arch height. Functional absence of the peroneals results in an imbalance that could lead to forefoot varus.

REFERENCES: Redfern D, Myerson M: The management of concomitant tears of the peroneus longus and brevis tendons. Foot Ankle Int 2004;25:695-707. Borton DC, Lucas P, Jomha NM, et al: Operative reconstruction after transverse rupture of the tendons of both peroneus longus and brevis: Surgical reconstruction by transfer of the flexor digitorum longus tendon. J Bone Joint Surg Br 1998;80:781-784

DISCUSSION: The most frequently described entrapment of the deep peroneal nerve is the anterior tarsal tunnel syndrome. This syndrome refers to entrapment of the deep peroneal nerve under the inferior extensor retinaculum. Entrapment can also occur as the nerve passes under the tendon of the extensor hallucis brevis. Compression by underlying dorsal osteophytes of the talonavicular joint and an os intermetatarseum (between the bases of the first and second metatarsals) have previously been described in runners.

REFERENCES: Kopell HP, Thompson WA: Peripheral entrapment neuropathies of the lower extremity. N Engl J Med 1960;262:56-60. Schon LC, Mann RA: Diseases of the nerves, in Coughlin MJ, Mann RA, Saltzman CL (eds): Surgery of the Foot and Ankle, ed 8. Philadelphia, PA, Mosby-Elsevier, 2007, vol 1, pp 675-677

DISCUSSION: The spring ligament is also known as the calcaneonavicular ligament and connects the calcaneus to the navicular. This ligament supports the talar head and is an important anatomic supporting structure of the medial longitudinal arch of the foot.

REFERENCES: Choi K, Lee S, Otis JC, et al: Anatomical reconstruction of the spring ligament using peroneus longus tendon graft. Foot Ankle Int 2003;24:430-436. Davis WH, Sobel M, DiCarlo EF, et al: Gross, histological and microvascular anatomy and biomechanical testing of the spring ligament complex. Foot Ankle Int 1996;17:95-102.

DISCUSSION: The deformity is long-standing, the hindfoot is immobile, and the radiographs reveal severe degenerative arthritis involving the entire hindfoot, severe deformity, and talonavicular dislocation. The “exostosis” responsible for the callus is the talar head; resection would severely destabilize the foot. Degenerative arthritis and fixed deformity preclude lateral column lengthening, medial slide calcaneal osteotomy, and talonavicular arthrodesis. Triple arthrodesis is the only viable option.

REFERENCES: Johnson JE, Yu JR: Arthrodesis techniques in the management of Stage II and III acquired adult flatfoot deformity. Instr Course Lect 2006;55:531-542. Pinney SJ, Lin SS: Current concept review: Acquired adult flatfoot deformity. Foot Ankle Int 2006;27:66- 75.

DISCUSSION: The symptoms and MRI scan indicate dislocated peroneal tendons. In this patient, the structure that needs to be repaired is the superior peroneal retinaculum. If the popping was coming from a torn peroneal tendon, repair would involve the peroneal longus or brevis tendon, but this is not shown in the MRI scan. The anterior talofibular ligament or the calcaneofibular ligament would need to be repaired if the patient had ankle instability due to an ankle sprain.

REFERENCES: Jones DC: Tendon disorders of the foot and ankle. J Am Acad Orthop Surg 1993;1:87-94. Timins ME: MR imaging of the foot and ankle. Foot Ankle Clin 2000;5:83-101. 9. PREFERRED RESPONSE: 4

DISCUSSION: The most common inherited neuromuscular disease seen by orthopaedic surgeons is CMT, which is an inherited autosomal-dominant disease. It is more commonly seen in men due to the nature of the inheritance. Identification of cavus deformity in the foot of a child should arouse suspicion.

REFERENCES: Richardson EG (ed): Orthopaedic Knowledge Update: Foot and Ankle 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2004, pp 135-143. Charcot-Marie-Tooth Disease (CMT) Penn State Hershey Medical Center. www.hmc.psu.edu/healthinfo/c/cmt.htm

DISCUSSION: Absolute toe pressures greater than 40 to 50 mm Hg are a good sign of healing potential. An ABI of greater than 0.45 favors healing, but indices greater than 1 are falsely positive due to calcifications in the vessels. Normal albumin is an overall indication of nutritional status. A transcutaneous oxygen level should be greater than 40 mm Hg for healing.

REFERENCES: Mizel MS, Miller RA, Scioli MW (eds): Orthopaedic Knowledge Update: Foot and Ankle 2. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1998, pp 113-122. Pinzur MS, Stuck R, Sage R: Benchmark analysis on diabetics at high risk for lower extremity amputation. Foot Ankle Int 1996;17:695-700.

11. PREFERRED RESPONSE: 5 Vignette describing the Silfverskiold Evaluates Gastroc tightness by relaxing the muscle through knee flexion (Gastroc crosses 2 joints) Difference >10 deg implies gastroc tightness Gastroc and soleus contracture: would not have increased dorsiflexion with knee flexion (Soleus only crosses ankle) Achilles laxity: increased dorsiflexion

12. PREFERRED RESPONSE: 1 During toe off the calcaneus is in the inverted position and is the transverse tarsal join locks. This allows for stability of the longitudinal arch of the foot. At heel strike the calcaneus moves into eversion and the transverse tarsal joint unlocks. The foot is a flexible structure at the first interval of gait for weight acceptance while it is a rigid structure while preparing for toe off. The inversion of the foot is likely due to the limb above the foot externally rotating and the passage of this movement across the ankle and subtalar joints. (Erez)