Principles of Deformity Correction Dr Andrew KS Lim Consultant Division of Paediatric Orthopaedic Surgery Department of Orthopaedic Surgery National University Hospital, Singapore Limb Deformity / Deficiency • Congenital - short femur - fibula hemimelia - skeletal dysplasia • Planes of Deformity - Coronal - Sagittal - Axial / Rotational • Acquired - trauma - infection - tumour - metabolic • • • • Clinical assessment Radiological measurements Pre-operative counseling Surgical correction X-ray weight bearing long leg film ? LLD ? Deformity Radiographic Assessment and Planning • Current / final predicted LLD • • • Axis malalignment test (MAT) MAD (mechanical axis deviation) Joint malorientation test (MOT) • • CORA (centre of rotation of angulation) TBL (transverse bisector line) • • • Osteotomy ACA (angulation correction axis) External fixator / FAP (fixator assisted plating) • • Distraction osteogenesis LON (lengthening over nail) / PAL (plate after lengthening) Normal mechanical and anatomical axes with joint orientation angles Childhood limb length discrepancy / angular deformity (mild) • Drill Epiphysiodesis (permanent) • 8-plate for guided growth (temporary epiphysiodesis) Limb deficiency, deformity (severe) • Deformity correction (gradual / acute): - Orthofix LRS - Circular fixators (Ilizarov / TrueLok; TSF / TL-Hex) - Exfix assisted internal fixation • Limb lengthening (gradual): - Orthofix LRS - Circular fixator - Lengthening over nail / plate after lengthening Rickets Malalignment test (MAT) Mechanical axis deviation (MAD) Anatomical Axis Resolution CORA 1st CORA 2nd CORA 1st CORA 2nd CORA Fixator Assisted Plating Osteogenesis imperfecta LLD Tibial deformity Oblique Plane Deformity 1st CORA 2nd CORA Fixator Assisted Plating Osteogenesis imperfecta LLD Distal femur valgus deformity CORA Distal femur corrective osteotomy Diaphyseal osteotomy for lengthening over nail Current LLD 6.4cm LLD Multiplier 1.24 Final predicted LLD 7.9cm Determine level of CORAs with anatomical axis planning - Femur - Tibia CORA 1 CORA 2 Measure magnitude of angular correction required Determine level of osteotomy and ACA suitable CORA 3 LRS monolateral fixator with femur bifocal osteotomy (acute angular correction and gradual lengthening) Distal fibula osteotomy with syndesmotic screw LRS T-Garche with proximal tibia osteotomy (gradual lengthening and angular correction) Phase of femur and tibia lengthening Submuscular plate after lengthening and angular correction 10 year old boy, treated CTEV with residual tibia shortening and intorsion Ilizarov fixator with proximal tibia corticotomy for lengthening Distraction osteogenesis Translation / rotation device Derotation Translational correction No shift in mechanical axis = no deformity (normal) OR = compensated (balanced) deformity Compensated (balanced) deformity Joint malorientation (ankle varus) Thank You
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