(Femoral head necrosis, aseptic necrosis, ischemic necrosis of the bone)
Osteonecrosis is a focal bone infarction, which may be caused by specific etiologic factors or idiopathic. It can cause pain, restricted movement, joint collapse and osteoarthritis. The diagnosis is made by X-rays and an MRI. In early stages, surgical procedures can slow the progression or prevent. In later stages, a joint replacement to relieve the pain and maintain function may be required.
In the United States each year about 20,000 people are diagnosed with osteonecrosis (ON). The hip (femoral head) is most commonly affected, followed by knee and shoulder (humerus). Less common wrist and ankle are affected. It is unusual for osteonecrosis that the shoulder or other less commonly affected areas are involved, without the hip is also involved. Osteonecrosis of the jaw has certain characteristics that differ from osteonecrosis in other places
Osteonecrosis is a focal bone infarction, which may be caused by specific etiologic factors or idiopathic. It can cause pain, restricted movement, joint collapse and osteoarthritis. The diagnosis is made by X-rays and an MRI. In early stages, surgical procedures can slow the progression or prevent. In later stages, a joint replacement to relieve the pain and maintain function may be required. In the United States each year about 20,000 people are diagnosed with osteonecrosis (ON). The hip (femoral head) is most commonly affected, followed by knee and shoulder (humerus). Less common wrist and ankle are affected. It is unusual for osteonecrosis that the shoulder or other less commonly affected areas are involved, without the hip is also involved. Osteonecrosis of the jaw has certain properties which differs from osteonecrosis at other locations Etiology The most common cause of osteonecrosis is a trauma. The nontraumatic osteonecrosis affects men more often than women, in> 60% of cases on both sides and occurs mainly in patients aged between 30 and 50 years. Traumatic osteonecrosis The most common cause of traumatic osteonecrosis is a displaced subcapital fractures of the hip. Osteonecrosis of intertrochanteric fractures is unusual. The incidence of osteonecrosis after hip dislocation is primarily related to the severity of the initial injury, but it can be higher if the dislocation is not reduced immediately. Fracture or dislocation can osteonecrosis by massive interruption or compression of adjacent blood vessels auslösen.Nichttraumatische osteonecrosis factors that cause or contribute to nichtraumatische osteonecrosis are listed in the table of non-traumatic risk factors for osteonecrosis. The most common factors are: chronic corticosteroid use excessive drinking non-traumatic risk factors for osteonecrosis alcohol chemotherapy coagulation disorders (eg, antiphospholipid antibody syndrome, hereditary thrombophilia, hypofibrinolytische disorders.) Corticosteroids Cushing’s syndrome Decompression sickness Gaucher Haemoglobinopathy dyslipidemia liver diseases Various diseases (eg. As chronic kidney disease, a rare hereditary metabolic disorders) organ transplant pancreatitis radiation SLE and other autoimmune connective tissue tumors smoking, the risk of osteonecrosis is increased as the dose of prednisone or an equivalent corticosteroid over several weeks or Mon ate> 20 mg / day, which usually leads to a cumulative dose of> 2000 mg. The risk of osteonecrosis is also increased, to be consumed when> 3 glasses of alcohol over several years (> 500 ml of ethanol / week). Some genetic factors increase susceptibility to osteonecrosis. Subtle coagulation abnormalities due to protein C or S deficiency or of antithrombin III or anticardiolipin antibodies (Thrombotic diseases in the overview) can be detected with osteonecrosis in a high percentage of patients. Some diseases that are associated with osteonecrosis, with corticosteroids (eg. As SLE) are treated. There are indications that the Osteonekroserisiko in many of these diseases is due primarily to the use of corticosteroids rather than to the associated disease. About 20% of cases are idiopathic. Osteonecrosis of the jaw has been in several patients, the high-dose i.v. have received bisphosphonate therapy reported. The non-traumatic osteonecrosis of the hip occurs seided at 60% of patients. The spontaneous osteonecrosis of the knee (spontaneous osteonecrosis of the knee, or Sponk SONK) is a process that (occasionally men) is in older women localized at the femoral condyle or tibial plateau. From the Sponk is believed that it is caused by an insufficient fracture (a kind of fragility due to normal wear in osteoporotic bone that occurs without direct trauma). Pathophysiology osteonecrosis means the destruction of osteocytes and bone marrow. The operations in the non-traumatic osteonecrosis include an embolism caused by blood clots or fat droplets, intravascular thrombosis and extravascular compression. After a vascular insult the repair processes to remove the necrotic bone and bone marrow and replacing them with vital tissue try. If it is a small heart attack, especially if it is not exposed to greater stress, these processes can be successful. However, these processes are not successful in about 80% of patients and infarct collapses gradually. Since osteonecrosis usually affects the ends of long bones, the articular surface overlying is flattened and irregular, with parts of broken bone, which eventually leads to osteoarthritis. Symptoms and complaints General symptoms Affected areas may remain asymptomatic until months after the vascular insult for weeks. Usually the pain develop only gradually, although they may be acute. With advancing collapse of the joint, the pain increased and is exacerbated by exercise and stress and rest gelindert.Gelenkspezifische symptoms Osteonecrosis of the hip causes pain in the groin, which may radiate to the thigh or the buttocks. The mobility is limited, and usually a limp developed. A Sponk usually causes sudden pain in the knee without prior previous trauma. The sudden appearance and the localization of the pain can help to distinguish it from the classical osteonecrosis. This pain is usually located on the medial side of the femoral condyle or tibial plateau and manifests itself with tenderness, effusion, pain with movement and a limp. Osteonecrosis of the humeral head often causes less pain and disability than for hip and knee involvement. With advanced p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: Arial 12.0px; color: # 3c3c3c; -webkit-text-stroke: # 3c3c3c; background-color: #ffffff span.s1 {font-kerning}: none} osteonecrosis show the patient’s pain and reduced mobility, although the passive mobility is less affected than the active range of motion. Symptomatic Synovialergüsse may occur, especially in the knee, the liquid is not flammable. Diagnostic X-rays MRI The suspicion of osteonecrosis in patients with: fractures, which are associated with an increased incidence of osteonecrosis, especially if persisting pain or worsen persistent spontaneous hip, knee or shoulder pain, especially if risk factors available for osteonecrosis are First overview images should be made. They can be for months without abnormalities. The earliest findings are localized areas increased radiolucency and sclerosis. Later, a subchondral crescent-shaped mark may occur. Thereafter, a massive collapse and a flattening of the articular surface is seen, followed by advanced degenerative changes. When the X-rays are normal or not diagnostic, should an MRI, which is more sensitive and specific, are performed. It should be presented both hips. Bone scans, however, are less sensitive and less specific than MRI and are now rarely performed. A CT is rarely necessary, although it can be useful sometimes to detect the joint collapse, which is not and sometimes not appear on the X-ray overview images in MRI. The laboratory tests are normal and not very meaningful in the detection of osteonecrosis usually. However, they could help to identify an underlying medical condition (eg. As coagulation disorders, hemoglobinopathies, lipid abnormalities). Symptomatic treatment measures (eg. As rest, physical therapy, NSAIDs) Surgical decompression or other methods to promote healing Hip Replacement Conservative measures Small, asymptomatic lesions may heal spontaneously and require no treatment. Larger lesions, symptomatic or asymptomatic, have a poor prognosis if left untreated, especially if they are located in the femoral head. To slow the progression or prevent and save the joint, early treatment is desirable. A completely effective therapy is not yet available. Conservative measures include drugs (eg. As bisphosphonates) and physical treatments (eg., Electric fields and acoustic waves). Drug therapy and physical treatments have proven in limited studies to be quite promising, but are not currently in common use. One limitation of the weight load or no load, the outcome can not improve alone. A Sponk is treated conservatively in the rule, and the pain disappear meist.Chirurgische therapy Surgical treatments are most effective when they are made before a bone collapse. They were most commonly used in the treatment of osteonecrosis of the hip, where the prognosis without treatment is worse than the other regions. DieDekompression bone oven is the method that is most frequently performed. One or more bone herd are removed from the necrotic region or several small Aufbohrungen or perforations made in an attempt to reduce the intraosseous pressure and to stimulate repair. The decompression of bone herd is technically simple, and the complication rate is very low, if the procedure is performed correctly. Protection against weight load (only tolerated carrying weight and mobility aid such as crutches or walker) is required for about 6 weeks. Most reports indicate satisfactory or good results in 65% of all patients and in 80% of patients whose hips have small, early lesions; However, the results can vary significantly. Other established methods include various proximal femoral osteotomy and bone grafting, both vascularized and nichtvaskularisierte. These procedures are technically demanding, requiring protection from weight bearing for up to 6 months, and have so far not often performed in the United States. The reports on indications and effectiveness are different. The procedures should be performed primarily at selected centers that have the surgical expertise and equipment to achieve optimal results. One approach that is currently being evaluated is the injection of autologous bone marrow into the necrotic lesion. Initial results are promising. If an extended collapse of the femoral head and degenerative changes in the hip socket cause severe pain and disability caused arthroplasty is usually the only way to relieve the pain effectively and improve mobility. Conventional treatment is total hip replacement. Good to very good results are achieved in 95% of hip and knee replacements, the complication rates are low, and patients take most daily activities within 3 months back on. Most replacement hip, knee hold for> 15 to 20 years. Two alternatives to total hip replacement are the Oberflächenersatzendoprothese (surface replacement arthroplasty, SRA) and the Hemi-SRA. The SRA involves the insertion of two metal caps, a a result of which a metal-to-metal joint is made in the pan and on the femoral head. The Hemi-SRA involves placing a metal cap only on the femoral head. It is only possible if the disease is limited to the femoral head and is seen as a bridging process. Due to the increasing incidence of local complications, the failure of the prosthesis and concerns about the possible long-term systemic effects of metal ions, these procedures are now performed less often than they did a few years ago. Osteonecrosis of the knee and shoulder can be treated more often in a conservative manner as osteonecrosis of the hip. Limited experience with decompression of bone oven are promising. In advanced stages, a partial or total joint replacement may be indicated. Prevention The risk of osteonecrosis caused by corticosteroids can be minimized by being used only in so far as they are essential, and by being so nidrig dosed, and administered as briefly as possible. To an induced decompression sickness osteonecrosis prevent that people should follow the accepted rules for decompression diving and at work in pressure environments. Excessive alcohol consumption and smoking should be discouraged. Several drugs (eg. As anticoagulants, vasodilators, lipid lowering agents) are examined to avoid osteonecrosis in high risk patients. Summary Osteonecrosis usually represents a complication of dislocated hip fracture is, however, increase factors that affect the blood supply to the bone (eg. As chronic corticosteroid use, excessive alcohol consumption), the risk of non-traumatic osteonecrosis. At osteonecrosis should be (occasionally in hand or ankle) and intended for specific fractures with unexplained non-traumatic pain in hip, knee or shoulder in patients when the pain persist or worsen. Although x-rays can be of diagnostic value, but MRI is more sensitive and specific. Smaller lesions may heal spontaneously, but most larger lesions, especially in the hip, evolve without treatment. Conservative treatment measures are not widely used because their effectiveness could not be clearly demonstrated. Surgical treatment is often indicated to limit the progression and / or ameliorate the symptoms, in particular at osteonecrosis of the hip.