Download - Non Union
Definition
• Nonunion failure of fracture bone to unite
Diagnosed can determined clinically / radiographically that healing has ceased and union is highly improbable
Etiology
(1) distraction and separation of the fragments, sometimes the result of interposition of soft tissues between the fragments;
(2) excessive movement at the fracture line(3) A severe injury that renders the local tissues
nonviable or nearly so(4) a poor local blood supply(5) infection
Hypertrophic
• Hypervascular • Possess bioligic capacity to heal but lack mechanical
stability• Callus formation present on x-ray• Elephant foot - abundant callus• Horse hoof - less abundant callus
A B C D
Hypertrophic non-unions often have florid streams of callus around the fracture gap – the result of insufficient stability. They are sometimes given colourful names, such as: (a) elephant’s foot. Atrophic non-unionsusually arise from an impaired repair process; they are classified according to the x-ray appearance as (b) necrotic, (c) gap and (d) atrophic.
Ultrasound• Ultrasound fracture stimulation devices
have shown ability to increase callus response in fresh fractures (shortens time for visible callus on x-ray)
• Use in nonunions remains theoretical
Electric Stimulation
• Piezoelectric nature of bone - stress generated electric potentials exist in bone and are related to callus formation
• Electromagnetic fields influence vascularization of fibrocartilage, cell proliferation & matrix production
Surgical Treatment
• Fibular osteotomy• Bone graft• Plate osteosynthesis• Intramedullary nailing• External fixation
Fibular Osteotomy
• Often used as adjunctive procedure to assist with deformity correction and surgical stabilization of tibia
Bone Grafting
• Osteoinductive - contain proteins or chemotactic factors that attract vascular ingrowth and healing
• Osteoconductive - contains a scaffolding for which new bone growth can occur
Bone Grafting
• Used to stimulate biologic response of healing in nonunions (usually atrophic nonunions)
• Also used to fill defects in fracture zone – i.e. up to 6 cm intercalary defects of long bones)
Bosse, MJ e.t.al. JBJS 1989
Plate Osteosynthesis• Restores function & stabilizes fracture fragments
directly• Compresses fragments in some circumstances to
augment healing• Often used with adjunctive bone graft
Intramedullary Nailing
• Mechanically stabilizes long bone nonunions as a load sharing implant
• Corrects malalignment• Reaming is initially detrimental to intramedullary
blood supply, but it does recover and is believed to stimulate biologic healing at fracture
• 45-year old lady has nonunion of closed fracture lower third shaft of tibia of nine months duration. The most likely cause of this nonunion is
A.comminution of the fractureB.distraction of the fragmentsC. interposition of soft tissueD.absence of muscle origin from itE. intact fibula