The Effect of Anticoagulant Therapy on Bone Repair

Efeito da heparina sódica e da enoxaparina na consolidação de fratura da tíbia no rato: avaliação clínica e anatomopatológica e biomecânica

“…Other authors also confirmed this hypothesis (1,4,10,12,16,18,20) . Other studies, however, did not find any effect of anticoagulants upon bone fracture repair (2,5,13,14,17) .…”

“…When the inflammatory response subsides, the necrotic tissue and exudate are reabsorbed and fibroblasts appear (3) . Disorders during this phase can interfere in bone consolidation and include insufficient formation of fibrin clot (18) , more persistent presence of hematoma (8) , hemorrhage athe the site of the fracture (1) , formation of an extensive hematoma resulting in vascularization deficit (16) , and more liquid consistency of hematomas (19) , all of them induced by anticoagulants.…”

“…According to the majority of authors, anticoagulants can induce changes in the proliferative phase of bone consolidation. Stinchfield et al (18) found a decreased number in bone matrix cells; Minola et al (10) found central fibrosis and a longer cartilaginous phase; Aulisa (1) observed delayed formation of new bone, greater callus, and intenser presence of cartilage; Rokkanen & Slätis (16) found longer time of callus maturation, with greater formation of cartilage; Flatmark (5) described abundant formation of cartilaginous tissue; Dodds et al (4) showed delayed ossification of callus and fracture; Nilsson & Granström (12) observed increased chondroid reaction; Wikesjo et al…”

“…The excessive formation of cartilaginous tissue was attributed to an abnormal repair (10) , greater size of the hematoma or to "some intrinsic property" of the anticoagulant (1) and poor vascularization (16) . Flatmark (5) and Nilsson & Granström (12) did not explained the phenomenon.…”

Drugs and fracture repair

“…In a German paper, heparin reduced the filling out of bore holes in cancellous rabbit bone, but this could not be shown for heparin fragments (Kock et al 2002). It turns out that the inhibition of fracture repair by heparin was shown in rabbits and dogs as early as 50 years ago (Stinchfield et al 1956). Preliminary data from my own laboratory suggest that clinically relevant doses of low molecular weight heparin inhibit both bone implant fixation and soft tissue repair in rats.…”