Osteomyelitis: infection of the bone

Osteomyelitis is one of the infectious diseases of the skeletal system. There are acute and chronic forms that both present themselves differently and are also treated

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Osteomyelitis - a brief explanation

Osteomyelitis is an infection of the bone caused by pathogens. The most common pathogens are bacteria, which usually enter the body through wounds, for example open fractures or surgical wounds. However, the introduction of foreign bodies, for example endoprostheses, and the presence of other basic diseases can lead to the development of a bone infection. Osteomyelitis is diagnosed primarily through imaging tests. The treatment of osteomyelitis is sometimes very complex depending on the stage and requires a lot of patience on the part of the person affected as well as a good knowledge of the disease from the treatment team. The therapy essentially consists of surgical measures and antibiotic therapy. The aim is to heal the infection (clean up the infection) as far as possible. If this is not possible, the infection should at least be relieved in order to maintain or restore the function of the affected limb and to eliminate or alleviate pain. If left untreated, there is a risk of severe secondary conditions such as loss of function of the limbs, amputations or life-threatening blood poisoning.

What is osteomyelitis?

Strictly speaking, the term osteomyelitis means "infection of the bone marrow". In the Anglo-American region, it is mostly used for inflammation of the entire bone. In German-speaking countries, the term "osteitis" has established itself as a generic term for the inflammation of the bone cortex and the bone marrow.

Osteomyelitis can always develop when germs such as bacteria, fungi or other pathogens settle on a bone or its adjacent tissue. This contact of the pathogens with the bone is what is known as contamination. The body reacts to the pathogen infestation with an infection. This can be local (limited to the location of the contamination) or general (affecting the whole body, for example in the form of increased inflammation values ​​or fever).

Causes: how does osteomyelitis develop?

Infection of the bone can develop in different ways. In some cases, the germs reach a bone through direct immigration from the environment, for example from a source of infection such as an abscess or an infected wound. Another possibility is the "coating" of pathogens via the bloodstream, for example after a dental treatment or joint operation. The spread of the pathogen via the bloodstream is known as the hematogenic form. Since the introduction of antibiotics, this form of the disease has become comparatively rare, at least in industrialized countries.

Bone infection after accidents / operations

In Germany, osteomyelitis occurs most frequently after accidents and after operations. It is one of the most common infections acquired in hospital (nosocomial wound infection). If an infection occurs after surgery, it is a complication of the procedure. Certain operations such as bowel operations, operations on the inflamed appendix or gall bladder, operations on abscessed jaws can never be carried out completely germ-free, if only because of the naturally occurring bacteria, for example in the intestine or in the oral cavity. Whole bundles of measures made it possible to significantly reduce the complication rates of wound infection after orthopedic and trauma surgery operations, but they are not at zero percent. The highest risk of infection is with open bone fractures with up to 30 percent. A fracture in which a part of the bone comes into contact with the outside world is referred to as open, for example as part of a spike or a defect in the skin. Infections after planned operations, for example when using a hip prosthesis, are rare (about one to three percent infection rate).

General and local factors / underlying diseases

Many other factors can contribute to the development of bone inflammation. On the one hand, this includes general factors such as:

  • Chronic diseases: Diabetes (diabetes mellitus), pronounced overweight or underweight, disorders of the liver or kidney function, side effects of cytostatics, cortisone, blood thinners, and other factors that weaken the immune system.

On the other hand, the "condition on site" (local) also plays an important role. Local factors that can increase the susceptibility to infection are, for example:

  • arterial and venous circulatory disorders, number of previous operations, duration of an operation or the size and type of implants (artificial material introduced into the body such as a hip prosthesis).

Classification of osteomyelitis

Osteomyelitis can be classified according to various criteria:

  • according to the cause: exogenous (externally conditioned) or endogenous (internal causes of infection)
  • according to its course and clinical manifestation in:

- acute (sudden onset, clear symptoms) or

- chronic (creeping, long-lasting, minor symptoms)

  • the duration between the presumed occurrence and the diagnosis of the disease in:

- Early infection: within four weeks or

- Late infection: more than four weeks have passed (presumably) since the start of the infection

These criteria are also decisive in determining the optimal therapy.

Symptoms: What are the symptoms of osteomyelitis?

Osteomyelitis can be indicated by pain (especially at rest, including at night) and general symptoms such as dizziness, fever or chills. At the affected area (locally, for example a surgical wound) there may be reddening, swelling, overheating or even a secretion of wound fluid.

Similar symptoms also occur after operations, but they regress quickly. An indication of the development of a wound healing disorder or even an infection can be the recurrence of the above-mentioned symptoms (two-stage, after a better course in the meantime) or an increasing deterioration, for example increasing reddening around the wound or increasing wound secretion.

Such symptoms can develop weeks or years after an accident or surgery. Osteomyelitis can also hide behind a multitude of other, often uncharacteristic complaints.

Neither the symptoms are always clear, nor are there strict definitions or individual examination parameters for determining osteomyelitis. It is therefore advisable to look for signs of osteomyelitis in cases with diffuse and uncharacteristic symptoms.

Diagnosis: how is osteomyelitis diagnosed?

Important indications of osteomyelitis arise from the patient's history (anamnesis) and the physical examination. Imaging procedures such as x-rays or magnetic resonance tomography (MRT) complement the diagnosis. Characteristic findings are often found here, especially in the case of a long-term illness. Occasionally, other diagnostic aids such as skeletal scintigraphy or positron emission tomography (PET) are used and provide important information about bone inflammation. Blood tests can be used to determine inflammation values ​​(especially the C-reactive protein, or CRP for short) and provide important, additional information.

With the above findings, an operative procedure can already be planned. Tissue samples that are histologically and bacteriologically examined are evidence of the disease. Punctures from bones are rare procedures and wound swabs are not suitable. The detection of the pathogen is important in order to be able to use suitable antibiotics in a targeted manner. The pathogens that are difficult to treat and that show numerous resistances are an increasing problem, i.e. they no longer respond to a large number of antibiotics. Pathogens such as MRSA or VRE belong to this group.

Therapy: How is osteomyelitis treated?

The aim of the treatment is to bring the infection to subside, to relieve pain and to preserve the affected limbs and their function as much as possible.

The aim is to cure the disease (curative treatment), but sometimes the state of health of an affected person allows only a less drastic and merely relieving treatment (so-called palliative or supportive treatment).

Surgical rehabilitation is the most important pillar of curative treatment for adults. Roughly speaking, this operational rehabilitation can be divided into different sections:

1.) Removal of the infected tissue

This means that foreign bodies (such as joint prostheses, plates and screws) and all inflamed tissue, such as the affected part of the bone and any surrounding soft tissue, are removed in one operation.

2.) "Transitional period"

Multiple operations over the course of many weeks are usually necessary until stable conditions of bones and joints as well as the surrounding soft tissue (muscles and skin) are restored. A renewed restoration of the anatomical relationships requires complete healing of the infection. In order to get the affected region germ-free again, different methods can temporarily be used depending on the affected region. These include, for example, certain "placeholders", so-called spacer prostheses (antibiotic-coated transitional prostheses). Special antibiotic carriers (such as antibiotic chains) can also be introduced to the affected area. These special antibiotic carriers are partly self-absorbing, which means that they dissolve by themselves after a certain time, so that no further operation is necessary to remove them. Special vacuum-negative pressure treatments are mainly used in the area of ​​the soft tissues. Occasionally, however, the goal can only be achieved by amputation.

3.) Recovery

After the infection has been treated with antibiosis and the infected tissue has been surgically removed, further operations are carried out to restore the anatomical relationships (reconstructive measures). These include interventions such as rebuilding the bone, stabilizing the bone with plates, nails or screws (osteosynthesis) or artificial joint replacement (revision prostheses or individual implants). So-called soft tissue defects (surgical closure of skin, subcutaneous tissue and muscles) are covered, depending on the size of the defect, either by direct skin and soft tissue closure or skin is removed from another part of the body and transferred to the area to be closed (free flap transplantation ).

Drug treatment / further measures

In addition, the person concerned receives a therapy with antibiotics adapted to the pathogen. Not all experts agree on how long treatment with antibiotics is necessary. There is an individually adapted concept. Often, after the initial administration of medication via the vein, tablets can then be switched to, so that the hospital stay can be shortened.
In addition, pain therapy and physiotherapy are usually required.


Treatment without surgery is only promising in rare situations. This includes, on the one hand, the palliative approach (see above) for inoperable patients, and on the other hand, acute osteomyelitis in childhood. If the affected child starts therapy with a suitable antibiotic very early after the onset of the first symptoms, in most cases a cure is possible without surgery.

Chronic osteomyelitis in childhood must be distinguished from this (see separate box below).

Special form: Chronic non-bacterial osteomyelitis in childhood

In the case of very rare forms of osteomyelitis in children and adolescents, even with modern methods, neither a cause of the disease can be found nor a triggering germ can be identified. Specialists group these special forms under the term "chronic non-bacterial osteomyelitis". Those affected with these clinical pictures usually need special treatment and care from a pediatrician who specializes in rheumatology.

Are there any preventive measures?

Many different factors have an influence on the risk of infection after an operation (postoperative) or after an injury (posttraumatic). This includes the quality of the initial wound care, the degree of soiling of the wound, the duration of the operation, the time or the surgeon's experience in the field. But general factors such as the general condition of the person affected, the circulatory situation (such as blood pressure or body temperature) or the choice and start of the accompanying antibiotic therapy can also have an influence.

In order to keep the risk of infection as low as possible, the patient is prepared as optimally as possible before the operation for planned operations (elective interventions). This includes, for example, an optimization of the water balance or good cardiovascular conditions. The choice of implants and the planned surgical technique (such as tissue-sparing access to the surgical area) can also minimize the risk of an infection after the operation. In some clinics, products for medical skin disinfection are also used before planned prosthetic operations. These washing kits (shower bath, shampoo, nasal ointment, mouth rinse) are given to the patient so that they can start washing their skin around three days before the planned operation.

In order to further reduce the risk of osteomyelitis, scientists are currently investigating whether special coatings on implants such as plates or endoprostheses can prevent bacterial colonization. Another approach is to activate the immune system to fight against certain bacteria. However, these procedures are not yet available in everyday medical practice.

Dr. Matthias Kemmerer

© BG Unfallklinik Frankfurt am Main GmbH

Our advisory expert:

Dr. Matthias Kemmerer is the senior doctor in septic surgery at the BG Unfallklinik Frankfurt am Main. He is also a specialist in surgery, special trauma surgery, sports medicine and emergency medicine.

Swell:

  • Working group of the Scientific Medical Societies in Germany (AWMF), acute and chronic exogenous osteomyelitis of long tubular bones in adults, valid until December 1st, 2022. Online: https://www.awmf.org/uploads/tx_szleitlinien/012-033l_S2k_Osteomyelitis_2018-01_1.pdf (accessed on October 5th, 2020)
  • Walter G, Kemmerer M, Kappler C, Hoffmann R, treatment algorithms of the chronic
    Osteomyelitis Dtsch Arztebl Int 2012; 109: 257-64. On-line:
    http://www.aerzteblatt.de/archiv/124585/Behandlungsalgorithmen-der-chronischen-Osteomyelitis (accessed on 05.10.2020)

Important NOTE:

This article contains general information only and should not be used for self-diagnosis or self-treatment. He can not substitute a visit at the doctor. Unfortunately, our experts cannot answer individual questions.

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