Enoxaparin prevents progression of stages I and II osteonecrosis of the hip.
In a prospective pilot study, we hypothesized that enoxaparin (60 mg/day for 12 weeks) would prevent progression of Stages I and II osteonecrosis of the hip associated with thrombophilia or hypofibrinolysis or both over > or = 108 weeks of followup versus untreated historic controls, with different treatment responses in primary versus corticosteroid-associated secondary osteonecrosis. Patients with one or more thrombophilic-hypofibrinolytic disorder and Ficat Stages I or II osteonecrosis of at least one hip were included. A blinded committee interpreted anteroposterior and frog-leg lateral radiographs at entry in the study and every 36 weeks to > or = 108 weeks. Maintenance of the disease at Stages I and II versus progression of the osteonecrosis to Stages III and IV requiring total hip replacement was the major end point. Sixteen patients had primary osteonecrosis (25 hips; 13 Stage I, 12 Stage II), and 12 had secondary osteonecrosis (15 hips; five Stage I, 10 Stage II). With no Enoxaparin-related complications, 19 of 20 hips (95%) with primary osteonecrosis were unchanged from Stages I and II osteonecrosis at > or = 108 weeks; 12 of 15 hips (80%) with secondary osteonecrosis progressed to Stages III and IV osteonecrosis. In primary osteonecrosis at > or = 108 weeks, survival of 95% hips, or 76% (19/25 hips, based on intent to treat), compared favorably with untreated historical controls (approximately 20% 2-year survival), comparable to 20% survival in secondary hip osteonecrosis. Enoxaparin may prevent progression of primary hip osteonecrosis, decreasing the incidence of total hip replacement.


METHODS
Therapeutic study, II-1 (prospective cohort study).
Glueck
Charles J
CJ
Cholesterol Center, Jewish Hospital, 3200 Burnet Avenue, Cincinnati, OH 45229, USA. glueckch@healthall.com
Freiberg
Richard A
RA
Sieve
Luann
L
Wang
Ping
P
D019644:Arthroplasty, Replacement, Hip; D001778:Blood Coagulation Disorders / Q000150:complications; D018450:Disease Progression; D017984:Enoxaparin / Q000627:therapeutic use*; D005260:Female; D005271:Femur Head Necrosis / Q000188:drug therapy* / Q000473:pathology; D005343:Fibrinolytic Agents / Q000627:therapeutic use*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011446:Prospective Studies; D019851:Thrombophilia / Q000150:complications; D016896:Treatment Outcome
D017984:Enoxaparin; D005343:Fibrinolytic Agents