summary Charcot-Marie-Tooth Disease, also known as peroneal muscular atrophy, is a common autosomal dominant hereditary motor sensory neuropathy, caused by abnormal peripheral myelin protein, that presents with muscles weakness and sensory changes which can lead to cavovarus feet, scoliosis, and claw foot deformities. Diagnosis is made with nerve conduction studies showing low nerve conduction velocities with prolonged distal latencies in the peroneal, ulnar, and median nerves. Treatment involves a multidisciplinary approach to address neuropathy, cavovarus and claw foot deformities, and scoliosis. Epidemiology Incidence most common inherited progressive peripheral neuropathy 40:100,000 Etiology Pathophysiology HMSN Type I abnormal myelin sheath protein is the basis of this degenerative neuropathy. results in a combination of motor and sensory disturbances. HSMN Type 2 intact myelin sheath with wallerian axonal degeneration that results in mild sensory and motor conduction velocities. pathoanatomy affected muscles become weak peroneus brevis peroneal involvement is typically first and most profound results in muscle imbalance and varus deformity tibialis anterior weakness results in dropfoot intrinsic muscles of hand and foot check for wasting of 1st dorsal interosseous in hands Genetics inheritance autosomal dominant duplication of chromosome 17 (most common) codes for peripheral myelin protein 22 (PMP 22) expressed in Schwann cells (most common) X-linked connexin 32 may also be autosomal recessive X-linked Orthopedic manifestations pes cavovarus claw toes hip dysplasia scoliosis hand muscle atrophy and weakness Classification The major categories of Charcot-Marie-Tooth are Types 1 through 7 an X-linked category Classification of CMT Type I A demyelinating condition that slows nerve conduction velocity Characteristics: 1. autosomal dominant 2. onset in first or second decade of life 3. most commonly leads to cavus foot 4. normal life expectancy 5. motor involvement more profound than sensory Type II Direct axonal death caused by Wallerian degeneration (not demyelination) Characteristics: 1. Usually less disabled than Type I 2. onset in second decade of life or later 3. most commonly leads to flaccid foot Presentation Symptoms motor deficits initial symptoms are distal weakness and atrophy of the distal muscles instability during gait clumsiness frequent ankle sprains difficulty climbing stairs lateral foot pain sensory sensory deficits are variable Physical exam lower extremity cavovarus foot (similar to Freidreich's ataxia) with hammer toes or clawing of toes usually bilaterally and symmetric. occurs due to unoposed pull of peroneus longus causing plantarflexion of the first ray and compensatory hindfoot varus. initially flexible, but progresses to a rigid deformity motor weakness peroneal weakness weakest muscles around foot and ankle anterior tibialis weakens next, but typically stronger than the peroneals can lead to drop foot in swing initially and later to a fixed equinus posterior tibialis stays strong for a prolonged period of time calf atrophy rarely significant present weak intrinsics including weak EDB and EHB clawtoes hyporeflexia or areflexia Coleman block test test to determine if hindfoot varus deformity is secondary to plantar-flexed first ray vs an independent component. If deformity corrects with Coleman block, this suggests a forefoot driven varus deformity. If deformity does not correct with Coleman block, this suggests hindfoot driven varus deformity. a rigid hindfoot will not correct into neutral upper extremity intrinsic wasting of hands weak pinch and grasp spine scoliosis may be evident on Adam's forward bend test Studies NCS low nerve conduction velocities with prolonged distal latencies are noted in peroneal, ulnar, and median nerves can also see low amplitude nerve potentials due to axonal loss Genetic Testing key component for diagnosis of CMT DNA analysis PCR analysis used to detect peripheral myelin protein 22 (PMP22) gene mutations chromosomal analysis duplication on chromosome 17 seen in autosomal dominant (most common) form Cavus Foot Deformity Introduction evaluation and treatment follows same principals for cavovarus foot pathophysiology plantar flexed 1st ray is initial deformity cavus caused by peroneus longus (more normal) overpowering weak tibialis anterior weak intrinsics and contracted plantar fascia varus caused by tibialis posterior (normal) overpowering weak peroneus brevis Treatment nonoperative accomodative shoe wear indications rarely sufficient except in mild deformity full-length semi-rigid insole orthotic with a depression for the first ray and a lateral wedge indications mild cavus foot deformity in adult (not indicated in children) supramalleolar orthosis (SMO) indications more severe cavovarus deformity recalcitrant to shoewear accomodations ankle foot orthosis (AFO) indications may be needed if equinus also present, resulting in equinocavovarus foot deformity works best if equinus is a dynamic defomrity (not rigid) lace-up ankle brace and/or high-top shoe or boots indications may consider in moderate deformities when patient does not tolerate the more rigid bracing with an SMO or AFO operative soft tissue reconstruction indications flexible deformity in adolescents with closed physes failed conservative management of fixed deformities performed with a combination of the following procedures plantar release (plantar fascia +/- Steindler stripping, i.e. release of short flexors off the calcaneus) indications cavus peroneus longus to brevis transfer indications plantar flexed first ray rationale decreases plantarflexion force on first ray without weakening eversion posterior tibial tendon transfer indications muscle imbalance: posterior tibialis typically is markedly stronger than evertors and maintains strength for a long time in most cavovarus feet may consider transfer of posterior tibialis to dorsum of foot if severe dorsiflexion weakness of anterior tibialis lengthening of gastrocnemius or tendoachilles (TAL) indications true ankle equinus outcomes gastrocnemius recession produces less calf weakness and can be combined with plantar release simultaneously (TAL should be staged several weeks after plantar release) Jones transfer(s) of EHL to neck of 1st MT and lesser toe extensors to 2nd-5th MT necks indications toe clawing combined with cavus foot performed if the indication is met and time permits 1st metatarsal dorsiflexion osteotomy indications flexible hindfoot cavus deformities (normal Coleman block test and/or passive hindfoot eversion past neutral) triple arthrodesis, lateral calcaneal slide or closed-wedge osteotomy indications performed if deformity does not correct with Coleman block test. Claw Toes Deformity Introduction ankle dorsiflexion weakness may result in the recruitment of toe extensors for assistance in the setting of intrinsic muscle weakness, increased toe extensor activity can lead to claw toe deformity, which becomes rigid with time Treatment operative Jones procedure indications for symptomatic claw toe deformity which has failed non-operative measures technique transfers extensor tendons of the great and lesser toes to the metatarsal neck goal is to increase contributions to ankle dorsiflexion and decrease clawing in order to relieve pain on the dorsum of the toes and the plantar aspect of the metatarsal heads Hip dysplasias Introduction hip dysplasia is sometimes associated with CMT (typically less than 10%) may present during adolescence in ambulatory patients Treatment pelvic osteotomy indications symptomatic hip dysplasia outcomes higher rate of sciatic nerve palsy after surgery Scoliosis Introduction often occurs in children with CMT ( ~ 10-20%) characteristic left thoracic and kyphotic curve distinguish from idiopathic scoliosis Treatment nonoperative bracing indications bracing rarely effective so not typically used operative fusion and instrumentation indications progressive deformity with scoliosis > 50 degrees
QUESTIONS 1 of 25 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Previous Next Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (OBQ13.217) An orthotic that provides laterally based hindfoot posting support would be most useful for which of the following conditions? QID: 4852 Type & Select Correct Answer 1 Painful accessory navicular 1% (49/4407) 2 Middle facet coalition 2% (67/4407) 3 Flexible flat foot 10% (424/4407) 4 Metatarsus adductus 2% (84/4407) 5 Flexible cavovarus foot 85% (3759/4407) L 2 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 5 Review Tested Concept Review Full Topic (SBQ12FA.6) A 25-year-old male has a foot-drop deformity of his right foot due to a chromosomal 17 duplication which continues to progress despite stretching, strengthening, and orthotic use. A clinical picture of his foot while attempting to dorsiflex his ankle is shown in Figure A. On examination, he has supple ankle and subtalar motion, an equinus contracture, and 5/5 plantar flexion and inversion strength. Which of the following is the most appropriate surgical intervention for this patient? QID: 3813 FIGURES: A Type & Select Correct Answer 1 Tibiotalar arthrodesis 1% (17/2032) 2 Combined tibiotalar and subtalar arthrodesis 1% (22/2032) 3 Tibialis posterior transfer to dorsum of foot with gastrocnemius lengthening 79% (1611/2032) 4 Flexor digitorum longus transfer to dorsum of foot with gastrocnemius lengthening 16% (315/2032) 5 Tibialis anterior transfer to peroneus brevis 2% (44/2032) L 2 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 Review Tested Concept Review Full Topic (OBQ12.248) A mutation of PMP22 located at chromosome 17p12 most likely leads to an initial presentation highlighted by a: QID: 4608 Type & Select Correct Answer 1 Weak tibialis posterior 9% (490/5736) 2 Weak peroneus longus 19% (1063/5736) 3 Strong peroneus brevis 2% (130/5736) 4 Strong peroneus tertius 1% (33/5736) 5 Weak tibialis anterior 69% (3949/5736) L 3 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 5 Review Tested Concept Review Full Topic Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (OBQ10.56) A 32-year-old male complains of lateral foot pain and a progressively awkward gait. He has a family history of "foot problems" and reports some minor burning and numbness in both feet. He has no other medical problems and takes no medications. Physical exam reveals bilateral cavus feet with clawing of the toes and intrinsic muscle wasting of the hands. A clinical photograph is shown in Figure A. Which of the following is responsible for the patient's initial symptoms and awkward gait? QID: 3144 FIGURES: A Type & Select Correct Answer 1 Weak gastrocnemius-soleus complex 3% (100/3273) 2 Peroneus brevis overpowering the posterior tibial tendon 6% (209/3273) 3 Tibialis anterior overpowering the peroneus longus 30% (979/3273) 4 Plantar flexion of the first ray 58% (1889/3273) 5 Clawing of the toes 3% (82/3273) L 3 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (OBQ10.224) A 22-year-old woman is concerned about frequent ankle sprains and an awkward gait. Lower extremity nerve conduction velocities show prolonged distal latencies in the peroneal nerves. DNA testing shows a duplication on chromosome 17. Which of the following images is most likely the radiograph of this patient? QID: 3323 FIGURES: A B C D E Type & Select Correct Answer 1 Image A 3% (77/3075) 2 Image B 15% (461/3075) 3 Image C 66% (2033/3075) 4 Image D 5% (163/3075) 5 Image E 11% (325/3075) L 3 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 Review Tested Concept Review Full Topic (OBQ10.129) The PMP22 (peripheral myelin protein 22) is found at the cytogenetic location found in Figure A. What pediatric congenital disorder is associated with a mutation of this gene? QID: 3222 FIGURES: A Type & Select Correct Answer 1 Duchenne's/Becker's muscular dystrophies 8% (251/3202) 2 Limb-girdle dystrophies 1% (45/3202) 3 Myotonic dystrophy 3% (105/3202) 4 Charcot-Marie-Tooth disease 81% (2581/3202) 5 Spinal muscular atrophy 6% (199/3202) L 2 Question Complexity D Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (OBQ08.29) A 5-year-old boy has bilateral cavus feet and genetic testing reveals duplication of the PMP (peripheral myelin protein) gene on chromosome 17. What is the most likely diagnosis? QID: 415 Type & Select Correct Answer 1 Myelodysplasia 3% (53/1871) 2 Ewings Sarcoma 0% (4/1871) 3 Charcot-Marie-Tooth Disease 96% (1788/1871) 4 Cerebral Palsy 1% (11/1871) 5 Poliomyelitis 0% (7/1871) L 1 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 Review Tested Concept Review Full Topic This is an AAOS Self Assessment Exam (SAE) question. Orthobullets was not involved in the editorial process and does not have the ability to alter the question. If you prefer to hide SAE questions, simply turn them off in your Learning Goals. (SAE07PE.65) A 12-year-old girl who has a history of frequent tripping and falling also has bilateral symmetric hand weakness, high arched feet, absent patellar and Achilles tendon reflexes, and excessive wear on the lateral border of her shoes. She reports that she has multiple paternal family members with similar deformities. She most likely has a defect of what protein? QID: 6125 Type & Select Correct Answer 1 Peripheral myelin protein-22 83% (575/692) 2 Dystrophin 8% (56/692) 3 Type I collagen 3% (20/692) 4 Alpha-L-iduronidase 2% (16/692) 5 Cartilage oligomeric matrix protein 2% (15/692) L 2 Question Complexity E Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 1 Review Tested Concept Review Full Topic (OBQ06.83) A 42-year-old woman with Charcot-Marie-Tooth disease complains of longstanding foot pain. Orthotics, bracing, and NSAIDs no longer provide relief. She has cavovarus hindfoot deformity that does not correct with Coleman block testing. Radiographs are notable for degenerative changes within the talocalcaneal and calcaneocuboid joints. Which of the following is the most appropriate treatment? QID: 194 Type & Select Correct Answer 1 Split tibialis posterior transfer 1% (18/1819) 2 Triple arthrodesis 82% (1487/1819) 3 Lateral closing wedge calcaneal osteotomy with peroneus longus to brevis transfer 14% (256/1819) 4 First metatarsal dorsal closing wedge osteotomy 1% (25/1819) 5 Achilles tendon lengthening 1% (20/1819) L 1 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 2 Review Tested Concept Review Full Topic (OBQ06.75) Plantar flexion of the first ray is the initial deformity seen in which condition? QID: 186 Type & Select Correct Answer 1 Oblique talus 2% (41/1803) 2 Kohler's disease 2% (37/1803) 3 Charcot-Marie-Tooth 87% (1560/1803) 4 Calcaneovalgus foot 6% (112/1803) 5 Juvenile hallux valgus 3% (46/1803) L 1 Question Complexity D Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 Review Tested Concept Review Full Topic (OBQ05.87) The cavus deformity in Charcot-Marie-Tooth disease is caused by what muscular imbalance? QID: 973 Type & Select Correct Answer 1 Peroneus brevis overpowering peroneus longus 3% (71/2504) 2 Tibialis anterior overpowering tibialis posterior 12% (309/2504) 3 Achilles overpowering tibialis anterior 3% (80/2504) 4 Extrinsic toe flexors overpowering intrinsics 7% (183/2504) 5 Peroneus longus overpowering tibialis anterior 74% (1850/2504) L 1 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 5 Review Tested Concept Review Full Topic (OBQ05.254) A 17-year-old male complains of a foot deformity that has progressed over the past 1 year. He has pain along the lateral border of his foot with walking. His father has had similar problems with both feet throughout his life. A clinical photograph of the foot is provided in Figure A. Proper management of this patient should include evaluation for which of the following findings? QID: 1140 FIGURES: A Type & Select Correct Answer 1 Acetabular dysplasia 51% (742/1453) 2 Cervical stenosis 24% (346/1453) 3 Uveitis 11% (153/1453) 4 Hypoplastic thumb 6% (88/1453) 5 Thrombocytopenia 8% (112/1453) L 2 Question Complexity D Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 1 Review Tested Concept Review Full Topic (OBQ05.47) Lateral forefoot and heel posts would be the appropriate orthotic for the foot deformities associated with which of the following conditions? QID: 83 Type & Select Correct Answer 1 Charcot-Marie-Tooth disease 75% (909/1212) 2 Stage II posterior tibial tendon insufficiency 17% (206/1212) 3 Stage III posterior tibial tendon insufficiency 4% (45/1212) 4 Charcot arthropathy 2% (20/1212) 5 Hallux rigidus 2% (22/1212) L 2 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 1 Review Tested Concept Review Full Topic (OBQ04.98) Hereditary motor-sensory neuropathy (HSMN) primarily affects the peripheral nervous system. Which of the following are features of the most common type of HMSN QID: 1203 Type & Select Correct Answer 1 Death of both upper and lower motor neurons in the motor cortex of the brain, the brain stem, and the spinal cord leads to muscle twitching and atrophy 4% (155/4315) 2 Impaired oxidation of branched chain fatty acids leads to neurologic damage, cerebellar degeneration, and peripheral neuropathy 5% (214/4315) 3 Genetic mutations in axons or myelin protein leads to severe, rapidly progressive neurological damage by adolescence and complete loss of ambulation 18% (765/4315) 4 Genetic mutations in axons or myelin protein leads to leg muscle atrophy, loss of sensation and proprioception in early adulthood 72% (3097/4315) 5 Movement disorder characterized by degeneration of midbrain neurons 1% (42/4315) L 2 Question Complexity D Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic (OBQ04.211) A 24-year-old male with hereditary motor sensory neuropathy complains of worsening bilateral foot pain with ambulation and limited walking tolerance. Clinical photographs are shown in Figures A and B. The deformity corrects with Coleman block testing. Radiographs of the left foot are provided in Figures C-E. Which of the following is the best initial management for this patient? QID: 1316 FIGURES: A B C D E Type & Select Correct Answer 1 Custom orthotics with posting of the lateral forefoot and lateral heel 72% (1064/1482) 2 Custom orthotics with posting of the medial forefoot and medial heel 8% (123/1482) 3 Custom orthotics with medial heel posting and lateral forefoot recession 8% (120/1482) 4 Gastrocnemius slide followed by dorsiflexion casting 2% (24/1482) 5 Dorsal first metatarsal osteotomy with calcaneal slide osteotomy 10% (146/1482) L 2 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 1 Review Tested Concept Review Full Topic (SBQ04PE.2) A 14-year-old male child presents with the increasing foot deformity shown in Figure A. On physical exam, it is noted that he is unable to walk on his heels and has decreased Achilles reflexes bilaterally. Coleman block testing reveals correctable hindfoot deformity. Which procedure is associated with improved clinical outcomes in patients with the above described condition? QID: 2187 FIGURES: A Type & Select Correct Answer 1 Transfer of peroneus brevis to peroneus longus 9% (114/1260) 2 Split anterior tibial tendon transfer to lateral column 20% (249/1260) 3 Triple arthrodesis 2% (25/1260) 4 Posterior tibial tendon transfer through the interosseous membrane to dorsum of the foot 61% (770/1260) 5 Lateral column lengthening calcaneal osteotomy 7% (90/1260) L 3 Question Complexity D Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic
All Videos (0) Podcasts (1) Pediatrics | Charcot-Marie-Tooth Disease Pediatrics - Charcot-Marie-Tooth Disease Listen Now 15:23 min 10/15/2019 753 plays 4.7 (3)