Pediatric Orthopaedic Surgery and the HMSNs

Robert M. Bernstein, M.D.

Reviewed and accepted by the 2011-2012 Neuromuscular Committee ofthe American Association of Neuromuscular & Electrodiagnostic Medicine Certified for

CME credit 10/2011 – 05/2020Reviewed 10/2017 by the 2017-2018 Neuromuscular Committee

Orthopaedic Problems

• Related to the type of HMSN• Weakness/gait abnormalities• Foot deformities/pain• Hand deformities/Problems with ADLs• Sensory abnormalities• Scoliosis• Hip dysplasia

Vertuallyall types

Cure!!

Basic ScienceResearch

CMT Today

Early Diagnosis

Clinical Disease

Function?

The Foot

Common Foot Deformities

• Equinus deformities and foot drop• Cavovarus (high arch, heel tilted in)• Toe Deformities

• Can we intervene early to improve function and delay or prevent the need for fusion 

surgery?

Problems?

Weakness & Imbalance

Rigid deformity

Flexible deformity

Time

Pain & Disability

NormalValgus

PathologicVarus

Goal

• A flexible, stable, plantigrade foot!

Current Treatment Options

• Physical therapy• Bracing• Tendon Lengthening• Transfers and osteotomies• Triple arthrodesis (fusions)

Physical Therapy

• Improve strength• Improve range of motion

Bracing

• Support• Fixes joint position• Replaces non‐functional muscle

Surgery

• Treat deformities not treatable with PT or Bracing

• *Rigid deformities and Cavus cannot be braced

Foot drop

• Steppage gait – Lack of Tib Ant Increased tripping

• Foot slap• May walk on tip‐toes (equinus)• Slight equinus• Not usually a problem• Severe Equinus (contracture)• Decreased balance, stability

Foot drop

• PT• Strengthening of Dorsiflexors• Routine stretching of Achilles• Start early!

Foot drop

• Bracing• Leafspring AFO• Dorsiflex assist AFO• Equinus• Night‐time stretching brace

Equinus

• Slight equinus usually not a problem• Severe:• Tripping• Difficulty with balance

• *True contracture cannot be braced

Equinus

• Tendon lengthening• Percutaneous• Brace after lengthening• Don’t overlengthen!• Equinus is better then calcaneus

Radiographic Evaluation

• Standing AP, Lateral• Locate the apex of deformity!!• Cobey Views

No! Yes!

Apex

Cavovarus

• Heel tilts in (varus)• High arch (cavus)• Claw toes• Calluses• Ankle sprains• Becomes rigid

Coleman Block Test

• Is the hindfoot varus rigid?

• Allow the 1st metatarsal head to drop.

• Does the varus correct?

Transfers/Osteotomy

• Realign hindfoot• Move functioning muscles• EHL, TA, PL‐PB• + 1st metatarsal osteotomy• May not be permanent (moving target)• No bridges burned 

Osteotomies

• Heel

• 1st Metatarsal

Surgery ‐ Rigid

• Transfers alone will not work!• Triple arthrodesis (fuse hindfoot)• + transfers

Fusion

• Places the foot in corrected position

• Reduces motion• Adds stress to other joints• 76% arthrosis of other joints at 21 years f/u

Surgery ‐ Rigid

• Fusions

Fusion• Pro

– Immediate results– “Permanent”

• Con– Limited motion– Accelerates degeneration of surrounding joints

Fusion

• Better plantigrade and stiff then cavovarus and stiff!

The Spine

Scoliosis

• 15‐30% of patients• Kyphosis common• Rarely responds to brace treatment• Spinal cord monitoring?

JBJS 2007;89:1504-1510

Scoliosis

The Hip

Hip Dysplasia

• Prevalence unclear• ?8‐20% of CMT patients• Natural history not well documented

Evaluation

• Newborn with known HMSN• Ultrasound of hips• Child with HMSN• Standing AP Pelvis every 2 yrs until skeletal maturity

Treatment

• Bracing likely ineffectual after newborn period• Infant: Pavilk Harness• Child: Surgical• Address acetabular dysplasia• Address femoral malalignment• *Avoid lengthening procedures like Salter Osteotomy

Orthop Clin N Am 37 (2006) 203-209

Summary

• Orthopaedic manifestations common in HMSNs

• Gait• Foot• Spine• Hip

Summary

• Early therapy for foot/ankle• Bracing• Surgery• Transfers and Osteotomies• Fusion last resort

Summary

• Scoliosis• Common in CMT 1a• Kyphosis• Bracing ineffective• Surgery • Hip• DDH• Regular radiographic evaluation• Surgical treatment

Thank you!