Avascular Necrosis (Aseptic Necrosis) of the hip represents a condition where the hip has at least temporarily lost the critical blood supply to the ball part (femoral head) of the hip. This can cause a condition where the bone begins to collapse at this weakened site and then arthritis can begin. Expert

Avascular necrosis (AVN), better known as osteonecrosis, of the femoral head, is "a disease that causes death of bone." Expert

avascular necrosis (AVN) Etiology ("PLASTIC RAGS"): P pancreatitis L lupus A alcohol S steroids T trauma I idiopathic, infection C caisson disease, collagen vascular disease R radiation, rheumatoid arthritis A amyloid G Gaucher disease S sickle cell disease

avascular necrosis (AVN) staging

Wheeless' Textbook of Orthopaedics
pathogenesis and risk factors: - Intravascular coagulation and osteonecrosis. - natural history - blood supply to femoral head: - diff dx: - synovitis; - transient osteoporosis - femoral neck stress frx: - metastatic disease; - trochanteric bursitis:

This patient had minimal tenderness over his hips, with mild limitation to his range of motion. Both hips had cystic changes in the femoral heads without collapse (Fig. 1). He had been treated 8 months previously with a single intramuscular dose of betamethasone (dose equivalent to 75.5 mg prednisolone) for an allergic condition. Izge Gunal and Vasfi Karatosun CMAJ • July 4, 2006; 175 (1).

when femoral neck frx occurs, intraosseous cervical vessels are disrupted; - incidence of AVN in undisplaced fractures is 11%; - only 1/3 of patients with AVN will require additional surgery where as 3/4 patients with non union will require reoperation; - risk of AVN generally corresponds to degree of displacement of the fracture of the femoral neck on the initial radiographs

Uses search string allintitle: ("avascular necrosis" OR osteonecrosis OR AVN) (hip OR "femoral head" OR "head of femur")
Note this is not comprehensive as it only finds pages with Hip AVN in the title.>16,000 July 2007

PubMed Search for Hip AVN as a major subject of the article and excluding Legg Calve Perthes
Search String "Femur Head Necrosis"[Majr:NoExp]
Yields 2879 papers in July 2007 so would likely need to be refined by addition of limits or subject restriction (eg AND pathology)

Avascular necrosis of the femoral head in sickle-cell disease. Treatment of collapse by the injection of acrylic cement. Hernigou P, Bachir D, Galacteros F. Henri Mondor Hospital, Creteil, France. In ten patients with sickle-cell disease, we used a new technique of cement injection for the treatment of 16 painful hips with a radiographic crescent line or flattening of the articular surface due to avascular necrosis. The necrotic bone and overlying cartilage are elevated by the injection to restore the sphericity of the femoral head. Five days after the operation, full weight-bearing was allowed with the help of crutches for three weeks. The time in hospital averaged eight days; the average blood loss was 100 ml. There was early pain relief and postoperative radiographs showed improvement in the shape of the femoral head. At a mean follow-up of 5 years (3 to 7), 14 of the 16 hips were still improved although some gave slight pain. Only two hips had required revision to total hip arthroplasty, at one year and two years respectively. The increasing longevity of patients with sickle-cell disease means that avascular necrosis will be an increasing problem. Total hip replacement has a poor prognosis because of the risks of infection, high blood loss, and early loosening. Cement injection does not have these problems and allows for earlier, more conservative surgery. (full text)

Anatomy: - extracapsular arterieal ring at the base of the femoral neck; - formed posteriorly by large branch of MFCA - formed anteriorly by smaller branches of LFCA; - superior & inferior gluteal artery have minor contributions; - ascending cervical branches - these give rise to retinacular arteries; - gives rise to subsynovial intra articular ring - artery of ligamentum teres; - derived from obturator or MFCA; - inadequate to supply femoral head with displaced fractures; - forms the medial epiphyseal vessels; - only small & variable amount of the femoral head is nourished by artery of ligamentum teres; - epiphyseal blood supply: - arises primarily from lateral epiphyseal vessels that enter head posterosuperiorly; - vessels from medial epiphyseal artery entering thru ligamentum teres; - epiphyseal arterial branches: - arise as arteries of subsynovial intraarticular ring; - two groups of epiphyseal arteries: lateral & inferior vessels; - metaphyseal blood supply: - arises from extracapsular arterial ring; - arise from branches of ascending cervical arteries, & subsynovial intra articular ring;

ISCHEMIC NECROSIS AS A COMPLICATION IN DELVELOPMENTAL DYSPLASIA
This is an 11 months old white male patient who had congenital dislocation of right hip. This was first detected 6 weeks of age. The patient was a breech child delivered by C-section. He is the first child for this 38 year old mother. At 6 weeks of age, he was placed in a Pavlik harness but this treatment was unsuccessful. Closed reduction was performed, but the hip redislocated. He was kept in an Ilfield brace for a short time and then had open reduction followed by 3 months in a spica cast. Following removal of the cast he redislocated again, and at that time the patient was referred to this Institute.

Avascular Necrosis of the Hip in Sickle Cell Disease

Cementation for Femoral Head Osteonecrosis: A Preliminary Clinic Study. Clinical Orthopaedics & Related Research. 412:94-102, July 2003. Wood, Mark L. MD; McDowell, Cathy M. RN; Kelley, Scott S. MD Abstract: Treatment for femoral head osteonecrosis has been less successful in late stages of the disease, after progression to collapse. The current authors treated 21 patients (22 hips) with Stage III osteonecrosis by a technique of open reduction and fixation with methylmethacrylate cement (cementation). The followup ranged from 1 to 3 years (average, 1.7 years). Patient progress was followed using preoperative and postoperative Harris hip scores, Western Ontario and McMaster Universities Osteoarthritis Index, and a health status questionnaire (Short Form-36). Patients were staged preoperatively using the Association Research Circulation Osseous international classification system and radiographic evaluation was done intraoperatively and postoperatively. The Harris hip score, Western Ontario and McMaster Universities Osteoarthritis Index, and Short Form-36 physical health scores improved significantly from 53.5 to 78.0, 66.0 to 48.1, and 27.0 to 40.0, respectively. The outcome was worse for patients with more advanced disease. Six patients, all with severe disease, had total hip arthroplasty. Cementation is technically simple, enables patients' immediate postoperative pain relief and improvement in mobility, and has the potential to restore and maintain the sphericity of the femoral head after collapse. The high failure rate (27%) at short-term followup, although comparable with other reported techniques, does not support generalized use for Stage III disease. Currently the use of this procedure is restricted to symptomatic, young patients (younger than 40 years), preferably with mild to moderate Stage III disease (degree of head involvement <30% and degree of collapse <4 mm).

Background Avascular necrosis (AVN) of the femoral head is a pathologic process resulting from interruption of blood supply to bone. AVN of the hip is poorly understood but is the final common pathway of traumatic or nontraumatic factors that compromise the already precarious circulation of the femoral head. Femoral head ischemia results in the death of marrow and osteocytes and usually results in the collapse of the necrotic segment. Osteonecrosis of the femoral head was first described in 1738 by Munro. In approximately 1835, Cuwilhier depicted femoral head morphologic changes secondary to interruption of blood flow. Since Mankin described 27 cases of AVN in 1962, the number of reported cases has increased steadily. (full text)