osteomyelitis

DR. GAJANAN PANDIT

OSTEOMYELITIS

DEFINITION

Osteomyelitis is defined as an inflammation of the bone caused by an infecting organism.

The infection may be limited to a single portion of the bone or may involve numerous regions such as the marrow, cortex, periosteum, and the surrounding soft tissue.

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OSTEOMYELITIS

CLASSIFICATION

Classification of osteomyelitis is based on numerous criteria, such as

Based on duration of symptoms.Based on mechanism of infection.Based on the host response to disease.

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OSTEOMYELITIS

CLASSIFICATION

Based on duration of symptoms.

AcuteSubacuteChronic

The time limits defining these classes are arbitrary.

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OSTEOMYELITIS

CLASSIFICATION

Based on mechanism of infection.

ExogenousHematogenous

Exogenous osteomyelitis is caused by open fractures, surgery (iatrogenic), or contiguous spread from infected local tissue.

The hematogenous form results from bacteremia.

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OSTEOMYELITIS

CLASSIFICATION

Based on the host response to disease.

PyogenicNonpyogenic

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OSTEOMYELITIS

Bacterial Associations

Hematogenous osteomyelitis is most commonly caused by S. aureus.

In the past, Haemophilus influenzae type B (HiB) was a common organism in children, but the advent of HiB vaccine has made it a rare cause.

Causes of osteomyelitis due to direct inoculation, such as into an open fracture, will be influenced by the environment in which the injury occurred. For example, injuries occurring in water may lead to infection with Aeromonas or Plesiomonas.

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Nail puncture wounds of the foot, particularly through a tennis shoe, are associated with infection with Pseudomonas aeruginosa

Underlying medical conditions of the host also influence the expected microbiology. Intravenous drug users may have P. aeruginosa and other gram-negative bacilli as causes of their osteomyelitis

Patients with sickle cell disease are prone to the development of Salmonella osteomyelitis.


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Osteomyelitis caused by fungal infections is more likely to be seen in immunocompromised hosts.

Diabetic foot infections leading to osteomyelitis often are polymicrobial, often involving anaerobes and gram-positive and gram-negative aerobic bacilli.

Patients infected with the human immunodeficiency virus (HIV) are at risk for a variety of unusual infections, including atypical mycobacteria.


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ACUTE HEMATOGENOUS OSTEOMYELITIS

This is the most common type of bone infection and usually is seen in children.

It is more common in males in all age groups.It is caused by a bacteremia which is common

occurrence in children.Bacteriological seeding of bone is generally

associated with other factors such as localized trauma, chronic illness, malnutrition, or an inadequate immune system.

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OSTEOMYELITIS

ACUTE HEMATOGENOUS OSTEOMYELITIS

In children, the infection generally involves the metaphysis of rapidly growing bone.

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OSTEOMYELITIS

CAUSES FOR MORE INCIDENCE OF METAPHYSEAL OSTEOMYELITIS

1. Hair pin bend vessels in metaphysis.

2. Increased vascularity to metaphysis causing pooling of blood. It has been aptly called ‘a lake of blood’.

3. Immature cells of metaphysis due to high turnover.

4. Relative lack of phagocytosis.04/13/23

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OSTEOMYELITIS

CAUSES FOR MORE INCIDENCE OF METAPHYSEAL OSTEOMYELITIS

5. Presence of degenerating cartilage cells which act as a good culture media.

6. Presence of end arteries in metaphysis.

7. More prone to trauma.

8. Presence of single endothelial lining in metaphyseal arteries.

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OSTEOMYELITIS

Pathogenesis

Introduction of bacteria.Infective embolus enters the nutrient artery.Trapped in small calibre vessels.Active hyperemia.Exudate and debris.Increased pressure in bone.Exudate travels along the paths of least

resistence.Subperiosteal abscess.Sequestrum.


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OSTEOMYELITIS

DIAGNOSIS

A diagnosis of acute osteomyelitis should be considered an emergency.

The presenting signs and symptoms may vary with the severity of the infection.

Symptoms include fever and chills, general malaise, irritability, pain, and swelling.

With lower extremity involvement, there is either a limp or an inability to bear weight.

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OSTEOMYELITIS

DIAGNOSIS

An infant with upper extremity involvement may exhibit pseudoparalysis; older children and adults with upper extremity involvement complain of pain on movement or use of the extremity.

It is important to localize the point of maximum tenderness, which is usually warm and swollen. In children it is generally in the metaphyseal region.

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OSTEOMYELITIS

DIAGNOSIS

It is also important to evaluate the adjoining joint for evidence of septic arthritis, which can occur as an extension of the adjoining osteomyelitis.

Osteomyelitis involving the neck of the femur, talus, and humeral head often leads to sepsis of the joint

because these foci are located within the joint capsule.

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OSTEOMYELITIS

DIAGNOSIS

Once the point of maximum tenderness is localized, aspirate the area, and send the pus or fluid obtained for Gram stain, culture, and sensitivity studies.

If tuberculosis or a fungal infection is suspected, obtain an acid-fast stain and tuberculosis and fungal cultures.

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OSTEOMYELITIS

DIAGNOSIS

When a joint effusion is present or joint involvement is suspected, aspirate the joint and confirm with an arthrogram.

The arthrogram helps document the location of the aspiration and is useful for positive as well as for negative aspirations, since it may also identify joint capsule rupture.

Aspiration of the hip joint under ultrasound guidance is very helpful in children and adults.

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OSTEOMYELITIS

DIAGNOSIS

The white blood cell count is generally elevated, depending on the severity of the infection, with an increase in immature or band cells.

The erythrocyte sedimentation rate and the C-reactive protein are usually elevated.

Obtain blood cultures in all cases of acute hematogenous osteomyelitis and in chronic osteomyelitis exacerbated by fever and bacteremia.

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OSTEOMYELITIS

DIAGNOSIS

Roentgenograms taken early in the disease process generally show soft-tissue swelling. Bony changes are not present until 7–10 days after the onset of infection.

Radionuclide bone scanning using radioactive-labeled isotopes, such as technetium-99m and, more specifically, gallium citrate-67 and indium-111-labeled white blood cells, is helpful in localizing the area of involvement and in helping diagnose the condition.

Aspiration is used for the diagnosis, especially when there is no drainage or sinuses, and in some cases bone biopsy may be necessary.

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OSTEOMYELITIS

DIAGNOSIS

Magnetic resonance imaging (MRI) has added a new dimension to the diagnosis, localization, and characterization of the extent of infection.

T1- and T2-weighted images are the initial screening techniques for diagnosing osteomyelitis.

The MR finding in osteomyelitis on T1-weighted image sequences is a low signal intensity due to a dark marrow signal and an increased signal intensity due to a bright marrow signal on the T2-weighted image sequences. MRI has decreased the need for bone scanning and provides more useful information.

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OSTEOMYELITIS

DIAGNOSIS

Sinograms are done whenever there is a sinus tract or open draining area from which the depth and extent of the infection can be determined.

Abscessograms are done whenever an abscess is present and frank pus is aspirated. The abscessogram will help outline the extent of the abscess cavity.

MRI, computed tomographic scanning, and radiographic tomogram are all useful tools in evaluating osteomyelitis.

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OSTEOMYELITIS

Radiographic Pathogenesis

The earliest signs of bone infection are soft-tissue edema and loss of fascial planes. (seen within 24 to 48 hours of the onset of infection)

The earliest changes in the bone are evidence of a destructive lytic lesion. (seen within 7 to 10 days after the onset of infection), and a positive radionuclide bone scan.

Within 2 to 6 weeks, there is progressive destruction of cortical and medullary bone, an increased endosteal sclerosis indicating reactive new bone formation, and a periosteal reaction.

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OSTEOMYELITIS

Radiographic Pathogenesis

In 6 to 8 weeks, sequestra indicating areas of necrotic bone usually become apparent; they are surrounded by a dense involucrum, representing a sheath of periosteal new bone.


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DIFFERENTIAL DIAGNOSIS

Acute Rheumatism:onset- gradual, pain- less acute, articular,

swelling confined to joint, affects more than one joint at the same time and is ‘flitting’ in nature.

Erysipelas:Less pain and general toxemia.

Haemophilia:Bleeding diathesis should be looked for.


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DIFFERENTIAL DIAGNOSIS

Cellulitis:No intense pain and general malaise is less.

Acute Pyogenic Arthritis:Features related to joint.

Ewing’s tumour or Osteosarcoma:Much less intense general illness.


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PRINCIPLES OF TREATMENT OF ACUTE OSTEOMYELITIS (Proposed by

NADE)

1. An appropriate antibiotic is effective before pus formation.

2. Antibiotics do not sterilize avascular tissues or abscesses, and such areas require surgical drainage.

3. If such removal is effective, antibiotics should prevent their reformation, and primary wound closure should be safe.

4. Surgery should not damage further already ischemic bone and soft tissue; and

5. Antibiotics should be continued after surgery.

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OSTEOMYELITIS

INDICATIONS FOR SURGERY IN ACUTE HEMATOGENOUS OSTEOMYELITIS

1. Presence of an abscess requiring drainage.

2. Failure of the patient to improve despite appropriate intravenous antibiotics.

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OSTEOMYELITIS

Subacute Hematogenous Osteomyelitis

More insidous onset.Lacks severity of symptoms.Diagnosis usually delayed.Temperature is only mildly elevated.Mild to moderate pain.Usually positive radiographs and bone scan.Often confused with malignancy.


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The indolent course is related toIncreased host resistence.Decreased bacterial virulence.Administration of antibiotics before onset of

symptoms.


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Classification:Gledhill and modified

by Roberts et. al.Type ICentral metaphyseal

lesion.DD: Langerhans’ cell

histiocytosis, Brodie abscess.


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by Roberts et. al.Type IIEccentric

metaphyseal lesion with cortical erosion.

DD: Eosinophilic granuloma, osteogenic sarcoma.


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by Roberts et. al.Type IIIDiaphyseal cortical

lesion.DD: Osteiod osteoma


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by Roberts et. al.Type IV:Diaphyseal lesion

with periosteal new bone formation, but without bony lesion.

DD: Ewings sarcoma.


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by Roberts et. al.Type V:Primary subacute

epiphyseal osteomyelitis

DD: Chondroblastoma.


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by Roberts et. al.Type VI:Subacute

osteomyelitis crossing physis to involve metaphysis and epiphysis.

DD: Tuberculosis, osteogenic sarcoma


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Diagnosis must be established by an open biopsy and culture.

Treatment consists of biopsy and curretage followed by treatment with appropriate antibiotics.


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Brodie Abscess

Localized form of subacute osteomyelitis.Involves long bones of lower extremity.C/f: intermittent pain of long duration, local

tenderness.X-rays:- lytic lesion with a rim of sclerotic

bone.T/t: open biopsy with curettage.


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CHRONIC OSTEOMYELITIS

The hallmark of chronic osteomyelitis is infected dead bone within a compromised soft-tissue envelope.

The infected foci within the bone is surrounded by sclerotic, relatively avascular bone covered by a thickened periosteum and scarred muscle and subcutaneous tissue.

This avascular envelope of scar issue leaves systemic antibiotics essentially ineffective.

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OSTEOMYELITIS


CLASSIFICATION:

Cierny and Mader classification based on

Physiological criteria and,Anatomical criteria

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Physiological criteria: are divided into 3 classes based on three types of host:

Class A hosts have a normal response to infection and surgery.

Class B hosts are compromised and have deficient wound healing capabilities.

Class C hosts, the results of treatment are potentially more damaging than the present condition.

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OSTEOMYELITIS


Anatomical criteria:

Type I: Medullary

Is characterised by endosteal disease.

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Type II: Superficial

Limited to surface of the bone.

Infection is secondary to a coverage defect.

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Type III: Localized

Stable, well demarcated lesion characterised by full thickness cortical sequestration and cavitation.

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Type IV: Diffuse

Lesion creates mechanical instability, either at presentation or after appropriate treatment.

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OSTEOMYELITIS

Radiographic Findings

Early stages- Moth – eaten appearance.Elevation of periosteum with subperiosteal

laminations of new bone.Sharply delineated areas of dense bone with

surrounding decalcification.Gradually, necrotic dense area is sorrounded

by white ring of involucrum.


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Sclerosing Osteomyelitis of Garre

Chronic form of disease in which the bone is thickened and distended.

Abscesses and sequestra are absent.Intermittent pain of moderate intensity and

usually long duration.Swelling and tenderness.X-ray: expanded bone with generalized

sclerosis.T/t: Fenestration of sclerotic bone and

antibiotics.


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TREATMENT:Surgery for chronic osteomyelitis consists of

sequestrectomy and resection of scarred and infected bone and soft tissue.

The goal of surgery is eradication of the infection by achieving a viable and vascular environment.

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OSTEOMYELITIS

SEQUESTRECTOMY AND CURETTAGE

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AFTERTREATMENT:

Protection of limbAntibioticsManagement of dead space.

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METHODS OF DEAD SPACE MANAGEMENT

PAPINEAU CANCELLOUS GRAFT

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OSTEOMYELITIS


LOCAL CLOSURE

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MYOPLASTY

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FREE BONE TRANSFER

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USE OF BONE TRANSPORT

ILIZAROV TECHNIQUE

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OSTEOMYELITIS

OPEN BONE GRAFTING

Papineau et. al. described an open bone grafting technique for the treatment of chronic osteomyelitis.

Based on following principles:1.Granulation tissue markedly resists infection.2.Autogenous cancellous bone grafts are rapidly

revascularized and are resistant to infection.3.The infected area is completely excised.4.Adequate drainage is provided.5.Adequate immobilization is provided and6.Antibiotics are used for prolonged periods.

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OSTEOMYELITIS

Papineau technique

The surgery is divided into three stages:

1.DEBRIDEMENT2.CANCELLOUS AUTOGRAFTING:- posterior

iliac crest, 3 to 4 cm long.3.SKIN CLOSURE

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OSTEOMYELITIS

Papineau technique

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OSTEOMYELITIS

Polymethylmethacrylate Antibiotic Bead Chains

Commonly used.RationaleBead pouch technique when primary closure

not possible.Aminoglycosides most commonly employed.Short term(10 days), long term(80 days) or

permanent implantation.Rationale for removal.Technique.

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OSTEOMYELITIS

Biodegradable Antibiotic Delivery System

Advantage over PMMA:- no second procedure, osteoinductive and osteoconductive property.

E.g. of carriers: BMP+ cancellous bone, Demineralised bone matrix(DBM) + CaSo4, CaPO4, Hydroxyappetite.

Problem with calcium based carriers.

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OSTEOMYELITIS

Other modalities

Soft tissue transfer.Ilizarov technique.Hyperbaric Oxygen Transfer.

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OSTEOMYELITIS

Complications

Growth disturbances.Pathological fracture.Muscle contractures.Secondary septicemia.Epithelioma.Joint stiffness.Amyloidosis.


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SURGICAL CONSIDERATIONS

TOURNIQUETSApply a tourniquet whenever possible except in

patients with sickle cell disease or significant peripheral vascular disease.

The tourniquet improves hemostasis and thus facilitates identification of the infection process.

In acute cases with swelling, cellulitis, or abscess formation, elevate the extremity for several minutes before inflating the tourniquet.

In chronic osteomyelitis without significant cellulitis or abscess formation, use an elastic bandage to extravasate the extremity before inflating the tourniquet

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OSTEOMYELITIS


DEBRIDEMENTThorough debridement of all sequestra and

necrotic and desiccated bone is essential. Do not remove viable infected bone, so as not to

create large bony defects. It is not necessary to debride viable infected bone.

Clinically dried out, exposed, desiccated bone is darker than normal and should be debrided. Necrotic bone that has not been exposed may appear at surgery more yellowish than viable bone, which is whitish. The main finding is that viable bone bleeds, whereas necrotic bone does not.

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OSTEOMYELITIS


DEBRIDEMENTUse of an osteotome to superficially shave the

outer cortex of the questionable bone results in small areas of punctate bleeding.

Some bone that may have been exposed to air may be viable; in these cases, the exposed outer cortex should be debrided with an osteotome down to good bleeding bone.

Evacuate all pus and abscess, and remove all necrotic and infected soft tissue.

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OSTEOMYELITIS


IRRIGATIONUse copious amounts of irrigating fluid, which

cleanses the area of purulent exudate, loose soft tissue, and bony fragments, and decreases the bacterial count.

Recommended:- 2 L of antibiotic solution containing 50,000 units of bacitracin and 1 million units of polymyxin per liter as the final irrigating solution.

Other antibiotics can be used for topical irrigation as well.

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WOUND MANAGEMENTThe decision to leave a wound open or to close it requires

careful judgment. In the majority of acute infections, and in all cases in which there is associated abscess formation with cellulitis and swelling, the wound should be left open.

In some cases of early postoperative infection, the wound may be closed over drainage tubes, as long as the wound is thoroughly clean and the infection is not anaerobic.

In cases of chronic osteomyelitis in which there is no significant cellulitis or abscess formation and in which the wound has been adequately debrided and converted to a clean wound, the wound may be closed over drainage tubes.

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OSTEOMYELITIS


WOUND MANAGEMENTIn some cases in which bone or metal will be

exposed if the wound is left open, a partial closure over the bone or metal may be desirable, as long as an adequate pathway has been provided for drainage. When there is any doubt, it is safest to leave the wound open.

If the wound is closed, the wound site must be examined daily for any signs of infection; if such signs appear, the wound must be opened.

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WOUND MANAGEMENTMany wounds heal nicely by secondary intention. In the

case of large wounds or when delayed closure is preferable, do not attempt closure until two criteria are met.

First, the wound should appear clinically healthy, with clean granulating tissue and without any purulent exudate or necrotic tissue. If infected necrotic tissues are present, redebride the wound until it appears healthy.

Second, once the clinical appearance of the wound is clean, take quantitative tissue cultures and do Gram stains. Wounds with either a positive Gram stain or quantitative tissue cultures with a bacterial count greater than 10-5 organisms should never be closed. (A positive Gram stain implies a bacterial count of greater than 10-5 organisms.)

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OSTEOMYELITIS


WOUND MANAGEMENTThese wounds should be considered infected and

reassessed for further surgical debridement and the appropriateness of the systemic antibiotic therapy.

In secondary closure of wounds, it is important to redebride the wound at the time of closure and to do en bloc resection of the granulating tissue for several reasons.

First, although the bacterial count is low, these tissues should still be considered contaminated; debridement will further reduce the bacterial count and thereby diminish the chance of infection.

Second, debridement allows for cleaner, healthier tissue to be approximated by wound closure or covered by muscle transfer.

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DRAINS When the wounds are closed, Silastic or polyethylene drains

may be used. Remove the suction drain in 48–72 hours. The drain allows

the removal of all hematoma and tissue fluid, and the collapse of the potential dead space. The drains should be removed under sterile conditions and the tip cut off and sent for culture and sensitivity tests.

The drain tends to attract whatever bacteria are present because it is a foreign body and because tissue fluids are removed through it.

In general, a positive culture of the drain tip is a bad prognostic sign: It means that bacteria remain behind.

Monitor the clinical course and wound site closely; if any clinical signs of wound infection reappear, it may be necessary to consider redebridement and reassessment of antibiotic therapy.

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WOUND PACKINGThe purpose of leaving a wound open is to allow drainage. Make certain, therefore, when packing wounds with gauze

or other materials, that packing does not obstruct drainage. If it does, the purulent exudate will be retained in the wound, possibly causing tissue breakdown and necrosis with secondary cellulitis or even abscess formation.

It is best to put wicks perpendicular to the open wound to allow free drainage. Wicks can be either povidone-iodine (Betadine)-soaked gauze, plain gauze, or fine-mesh gauze. The size varies with the size of the wound. The ends of the wicks should always protrude through the skin edges to allow easy access and removal and to prevent retention.

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PRINCIPLES OF TREATMENT OF INFECTED UNUNITED FRACTURES AND

NONUNIONS

The principles of treatment are infection control, stabilization of the fracture, soft-tissue coverage, and bone graft of ununited fractures and large bone defects.

Infection control includes irrigation and debridement, culture and sensitivities, and antibiotic therapy. In chronic osteomyelitis, obtain aerobic, anaerobic, and fungal cultures. Recent studies have advocated taking of multiple deep cultures from purulent material, soft tissue, and bone

Stabilization of the ununited fracture or nonunion is essential. Soft-tissue coverage may require the use of local muscle flaps and free vascularized muscle flaps for soft-tissue defects or an inadequate soft-tissue envelope after control of the osteomyelitis.

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PRINCIPLES OF TREATMENT OF INFECTED UNUNITED FRACTURES AND

NONUNIONS

Local muscle flaps and free vascularized muscle transfers also help by bringing in a new blood supply, which is important in host defense mechanisms, antibiotic delivery, and osseous and soft-tissue healing. For the tibia, use the gastrocnemius muscle for proximal-third defects, the soleus for middle-third, and for the distal-third, free vascularized muscle transfers.

For local muscle transfers, it is important to assess the muscle preoperatively and not to transfer damaged muscle. Also avoid using crushed or badly damaged muscle, as flap necrosis or flap complications may result. In these cases, use free vascularized tissue transfer. Do preoperative angiograms on patients whose vascular status has been altered from any cause.

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OSTEOMYELITIS

osteomyelitis

Health & Medicine

causes of osteomyelitis

adjoining osteomyelitis

mechanism of infection

common type of bone

duration of symptoms

growing bone

common organism

host response