The effects of enoxaparin on the reparative processes in experimental osteonecrosis of the femoral head of the rat

Abstract

The blood supply of one femoral head of 6-month-old rats was severed by incising the periosteum of the neck and cutting the ligamentum teres. The rats were killed on the 30th postoperative day and the femoral bones were obtained for semiquantification of the reparative processes in the necrotic heads. Fourteen rats were treated with enoxaparin and 14 untreated animals served as controls. Statistically, the amounts of necrotic bone in the epiphysis were less, the extent of remodeling of the femoral heads was milder, and the articular cartilage degeneration was slighter in the enoxaparin-treated than untreated rats. There was no significant difference in the quantities of newly formed bone in femoral heads of treated and untreated rats. These findings are in agreement with the known effects of unfractionated and low-molecular-weight heparins which enhance osteoclastic bone resorption and angiogenesis and decrease osteoblastic bone formation. The former activities, operative in minimizing the structural distortion of the femoral head, oppose the crucial event in the pathogenesis of post-osteonecrotic osteoarthritis.

Heritable Thrombophilia-Hypofibrinolysis and Osteonecrosis of the Femoral Head

“…These findings, congruent with the amelioration of idiopathic ON with low-molecular-weight heparin therapy [31], suggested to us and other authors [1,5,8,11,41,49,50,62,65,76,79,80] that thrombophilia-hypofibrinolysismediated thrombosis is a potentially reversible cause of ON of the head of the femur. Experimental models of ON [12,13,52,63] and Legg-Calve-Perthes disease [57] implicate venous occlusion as a precipitating event with subsequent increased intraosseous pressure, reduced arterial inflow, ischemia, and infarction. We believe thrombophilia-hypofibrinolysis, promoting deep osseous venous thrombosis, initiates this cascade [5,12,29,31,32,44,46,57,63].…”

Treatment with acetylsalicylic acid prevents short to mid-term radiographic progression of nontraumatic osteonecrosis of the femoral head: a pilot study

“…Medical therapies as well as nonpharmacological therapies, including modified weight bearing, hyperbaric oxygen and extracorporeal shock wave therapy, have been the subject of multiple investigations, including several prospective studies. 18,[32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47] Bisphosphonates have received specific attention owing to their known effect of decreasing osteoclast-mediated bone turnover that theoretically could prevent subchondral bone collapse. A randomized controlled trial assessing 54 hips reported significantly lower rates of disease progression and need for arthroplasty in patients treated with bisphosphonates for 2 months.…”

Effects of alendronate medication on the fate of the necrotic femoral head of rats with or without core decompression

“…We have previously sought means to hinder or delay the destructive remodeling of the necrotic femoral heads, but our endeavors are to no avail in as much as experimentally accelerating the healing processes hastens the evolution of the osteoarthritis-like disorder [6,[8][9][10][11]. We have consequently selected alendronate medication of rats with femoral capital osteonecrosis in the expectation that slowing down the function of the osteoclasts [12][13][14] would preserve the normal shape of the femoral epiphysis for a longer time period than in the untreated control animals.…”