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External Fixation and Stapling for Angular Deformities
and Limb Length Discrepancies in Multiple Hereditary Exostosis (MHE)
Abstract 2005 MHE Conference
John E. Herzenberg, MD, FRCSC
Head of Pediatric Orthopaedics, Sinai Hospital of Baltimore
Co-Director, International Center for Limb Lengthening
Rubin Institute for Advanced Orthopedics Baltimore, MD 21215
General considerations: MHE causes valgus in the knee and ankle.
The cause is tethering of the growth plates, leading to asymmetric growth and limb length
discrepancy. Treatment of valgus (knock knee) deformity improves awkward gait, and prevents
abnormal joint loading that can cause premature knee arthritis. Treating leg length discrepancy
improves gait mechanics and prevents low back pain caused by pelvic tilt. Mild angulations in growing
children can be treated with hemi-epiphyseal stapling using Blount staples (Zimmer) in pre-teens, or
the new 8-plate (Orthofix) in children as young as 3 years (where staples might dislodge).For
children near skeletal maturity, and for adults, osteotomy and gradual correction with external
fixators is the most accurate way to correct angulation and length problems. The TSF (Smith &
Nephew) and MAC (EBI) enable multiplanar correction with simultaneous lengthening. For adults
without angulation, there is an implantable telescopic lengthening nail called the ISKD (Orthofix)
which lengthens the femur or tibia without an external fixator.
Valgus knee: Assess angulation on a long standing x-ray that includes hip, knee and ankle on a
single cassette and a long lateral film. Measure the mechanical axis deviation (MAD), lateral distal
femoral angle (LDFA), medial proximal tibial angle (MPTA), posterior proximal tibial angle (PPTA) and
posterior distal femoral angle (PDFA). These tests usually localize the problem to the proximal tibia.
Consider stapling for young patients with sufficient growth. Older children are treated with gradual
correction using an external fixator and corticotomy. Consider simultaneous peroneal nerve
decompression and resection of the fibular head osteochondroma.
Valgus ankle: Assess angulation on standing films centered on the ankle. Measure the lateral distal
tibial angle (LDTA) and anterior distal tibial angle (ADTA). Evaluate for presence of compensatory
subtalar contractures. Staple the medial distal tibia for younger patients without subtalar
contractures. If there is an established subtalar contracture that makes the foot plantigrade, then
the valgus tilt of the ankle might best be left untreated.
Leg length discrepancy: For discrepancies under 2 cm, use shoe lifts. In skeletally immature
patients, consider epiphyseodesis of the long leg. Lengthening the short leg is preferred if there is
residual angular deformity to be corrected. Predicting adult height and limb length discrepancy with
the Multiplier method helps families to decide which option to choose. In mature patients, without
angulation, lengthen either with ISKD or lengthening over nail (LON) methods to eliminate or
decrease external fixation time. Shortening the long leg in adults by up to 4 cm can be safely done
in the femur over an intramedullary nail as an alternative to lengthening.
Forearm problems: For the short ulna without angulation in young children, lengthen the ulna with
an external fixator to prevent the secondary changes of distal radius ulnar deviation and radial head
dislocation. Older children need more complex treatment: ulnar lengthening with distal radio-ulnar
fixation to gradually reduce the dislocated radial head, followed by staged distal radial osteotomy for
angular correction. Mild ulnar deviation of the distal radius may be amenable to hemi-epiphyseal
stapling techniques.
and Limb Length Discrepancies in Multiple Hereditary Exostosis (MHE)
Abstract 2005 MHE Conference
John E. Herzenberg, MD, FRCSC
Head of Pediatric Orthopaedics, Sinai Hospital of Baltimore
Co-Director, International Center for Limb Lengthening
Rubin Institute for Advanced Orthopedics Baltimore, MD 21215
General considerations: MHE causes valgus in the knee and ankle.
The cause is tethering of the growth plates, leading to asymmetric growth and limb length
discrepancy. Treatment of valgus (knock knee) deformity improves awkward gait, and prevents
abnormal joint loading that can cause premature knee arthritis. Treating leg length discrepancy
improves gait mechanics and prevents low back pain caused by pelvic tilt. Mild angulations in growing
children can be treated with hemi-epiphyseal stapling using Blount staples (Zimmer) in pre-teens, or
the new 8-plate (Orthofix) in children as young as 3 years (where staples might dislodge).For
children near skeletal maturity, and for adults, osteotomy and gradual correction with external
fixators is the most accurate way to correct angulation and length problems. The TSF (Smith &
Nephew) and MAC (EBI) enable multiplanar correction with simultaneous lengthening. For adults
without angulation, there is an implantable telescopic lengthening nail called the ISKD (Orthofix)
which lengthens the femur or tibia without an external fixator.
Valgus knee: Assess angulation on a long standing x-ray that includes hip, knee and ankle on a
single cassette and a long lateral film. Measure the mechanical axis deviation (MAD), lateral distal
femoral angle (LDFA), medial proximal tibial angle (MPTA), posterior proximal tibial angle (PPTA) and
posterior distal femoral angle (PDFA). These tests usually localize the problem to the proximal tibia.
Consider stapling for young patients with sufficient growth. Older children are treated with gradual
correction using an external fixator and corticotomy. Consider simultaneous peroneal nerve
decompression and resection of the fibular head osteochondroma.
Valgus ankle: Assess angulation on standing films centered on the ankle. Measure the lateral distal
tibial angle (LDTA) and anterior distal tibial angle (ADTA). Evaluate for presence of compensatory
subtalar contractures. Staple the medial distal tibia for younger patients without subtalar
contractures. If there is an established subtalar contracture that makes the foot plantigrade, then
the valgus tilt of the ankle might best be left untreated.
Leg length discrepancy: For discrepancies under 2 cm, use shoe lifts. In skeletally immature
patients, consider epiphyseodesis of the long leg. Lengthening the short leg is preferred if there is
residual angular deformity to be corrected. Predicting adult height and limb length discrepancy with
the Multiplier method helps families to decide which option to choose. In mature patients, without
angulation, lengthen either with ISKD or lengthening over nail (LON) methods to eliminate or
decrease external fixation time. Shortening the long leg in adults by up to 4 cm can be safely done
in the femur over an intramedullary nail as an alternative to lengthening.
Forearm problems: For the short ulna without angulation in young children, lengthen the ulna with
an external fixator to prevent the secondary changes of distal radius ulnar deviation and radial head
dislocation. Older children need more complex treatment: ulnar lengthening with distal radio-ulnar
fixation to gradually reduce the dislocated radial head, followed by staged distal radial osteotomy for
angular correction. Mild ulnar deviation of the distal radius may be amenable to hemi-epiphyseal
stapling techniques.
Research authored by Dr. Herzenberg
Click the tab and a window will appear.
List of Publications via PubMed
(NIH National Library of Medicine)
List of Publications via PubMed
(NIH National Library of Medicine)
John E. Herzenberg, M.D., FRCSC
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| Dr. Herzenberg's Clinal Presentation |
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National Library of Medicine, Directory of Health Organizations (SIS) website, as well as the link for Patient
Information on The Diseases Database a cross-referenced index of human disease, and the Intute: health & life
sciences a free online service providing access to the very best Web resources for education and research
located in the UK
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