Osteomyelitis Treatment & Management

Updated: Mar 01, 2018
  • Author: Stephen Kishner, MD, MHA; Chief Editor: Murali Poduval, MBBS, MS, DNB  more...
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Treatment

Approach Considerations

Surgery is indicated for osteomyelitis if the patient has not responded to specific antimicrobial treatment, if there is evidence of a persistent soft tissue abscess or subperiosteal collection, or if concomitant joint infection is suspected. Debridement of necrotic tissues, removal of foreign materials, and sometimes skin closure of chronic unhealed wounds are necessary in some cases.

Although vertebral osteomyelitis does not usually necessitate surgical treatment, indications include failure to respond to antimicrobial therapy, neural compression, spinal instability, or drainage of epidural or paravertebral abscesses.

The Infectious Diseases Society of America (IDSA) has published clinical practice guidelines for the diagnosis and treatment of native vertebral osteomyelitis in adults, including recommendations regarding antibiotic therapy and surgical intervention (see Guidelines). [36]

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Medical Therapy

Antibiotic treatment should be based on the identification of pathogens from bone cultures at the time of bone biopsy or debridement. [1, 4] Bone cultures are obtained first, and suspected pathogens are then covered by initiation of a parenteral antimicrobial treatment. However, treatment may be modified once the organism is identified. Parenteral and oral antibiotics may be used alone or in combination depending on microorganism sensitivity results, patient compliance, and infectious disease consultation.

Prophylactic treatment with the bead pouch technique has been suggested in open fractures to reduce the risk of infection. Systemic antibiotics supplemented with antibiotic beads are preferred to systemic antibiotics alone.

Local antibiotic therapy with gentamicin-impregnated Septopal beads, though available in Europe, is controversial. [37]  Factors involved in the debate include the length of implantation, the need for removal, and the choice of nonabsorbable versus bioabsorbable delivery vehicles. Prolonged implantation of antibiotic beads and spacers remains controversial owing to the risk of secondary infection and development of resistant organisms. Secondary infection stems from the beads, which may serve as a foreign body upon complete elution of antibiotic.

Traditionally, antibiotic treatment of osteomyelitis consists of a 4- to 6-week course. [4] Animal studies and observations show that bone revascularization following debridement takes about 4 weeks. However, if all infected bone is removed, as in forefoot osteomyelitis, antibiotic therapy can be shortened to 10 days. [38]

Oral antibiotics that have been proved to be effective include clindamycin, rifampin, trimethoprim-sulfamethoxazole, and fluoroquinolones. Clindamycin is given orally after initial intravenous (IV) treatment for 1-2 weeks and has excellent bioavailability. It is active against most gram-positive bacteria, including staphylococci. Linezolid is active against methicillin-resistant staphylococci and vancomycin-resistant Enterococcus. It inhibits bacterial protein synthesis, has excellent bone penetration, and is administered intravenously or orally.

Oral quinolones are often used in adults for gram-negative organisms. Quinolones have excellent oral absorption and may be used as soon as patient is able to take them. Rifampin has an optimal intercellular concentration and a good sensitivity profile for methicillin-resistant staphylococci. It is used in combination with cell wall–active antibiotics to achieve synergistic killing and to avoid rapid emergence of resistant strains.

Empiric therapy is necessary when it is not possible to isolate organisms from the infection site. [1] Hospital-acquired infections are usually derived from methicillin-resistant staphylococci. Infections contracted outside the hospital are often polymicrobial with the presence of gram-negative bacteria.

Infection may fail to improve owing to the ability of bacteria to resist antibiotics. Some bacteria, such as S epidermidis in prosthesis infections, adhere to a biofilm that protects the organism from phagocytosis and impedes delivery of the antibiotic. The use of rifampin in combination with other antibiotics has been found to be more effective than monotherapy for treating infection associated with surgical hardware. [1, 39]

Suppressive antibiotic therapy should also be directed by bone culture and is given orally when surgery is contraindicated. [4] Good bioavailability, low toxicity, and adequate bone penetration are important factors in treatment. If the infection recurs after 6 months of suppressive antibiotic treatment, a new lifelong regimen of suppressive therapy may be tried.

Extensive studies of suppressive therapy with administration of rifampin, ofloxacin, fusidic acid, and trimethoprim-sulfamethoxazole for 6-9 months have been performed in patients with infected orthopedic implants. Studies have shown that, after discontinuance of antibiotics, no recurrence of infection occurred in 67% of patients treated with trimethoprim-sulfamethoxazole, 55% of patients treated with rifampin and fusidic acid, and 50% of patients treated with rifampin and ofloxacin. [4]

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Surgical Therapy

Preoperative planning

The Cierny-Mader classification system (see Workup) plays an important role in guiding treatment. As described above, stage 1 and 2 disease usually do not require surgical treatment, whereas stage 3 and 4 respond well to surgical treatment. In Cierny-Mader class C hosts, treatment may be more harmful than the osteomyelitis itself. [5]

Operative treatment consists of the following [4] :

  • Adequate drainage
  • Extensive debridement of necrotic tissue
  • Management of dead space
  • Adequate soft-tissue coverage
  • Restoration of blood supply

When a fracture and stable hardware are involved, surgery is used to treat a residual infection after suppressing the infection until the fracture heals. Techniques involve second-stage hardware removal followed by treatment of an infected nonunion, often with an external fixator. External fixators, plates, screws, and rods may be used to restore skeletal stability at the infection site. [4] Because hardware tends to become secondarily infected, external fixation is preferred to internal fixation.

Remission or cure is most likely with extensive debridement, obliteration of dead space, removal of any hardware, and appropriate antibiotic therapy.

Debridement of all nonviable or infected tissue is critical because retained necrotic or infected debris can result in osteomyelitis recurrence. Bone debridement is performed until punctuate bleeding is noted. [4] The remaining tissue is still considered contaminated even after adequate debridement of necrotic tissue. Studies have shown that marginal resection may be sufficient in normal hosts. However, in compromised hosts, extensive resection seems to be much more important.

“Dead space” refers to the soft tissue and bony defect left behind after debridement. [4] Appropriate management of this space is necessary to reduce the risk of persistent infection from poor vascularization of the area and to maintain the integrity of the skeletal part.

Dead space must be filled with durable vascularized tissue, sometimes from the fibula or ilium. Antibiotic-impregnated beads may be used for temporary sterilization of dead space. Vancomycin, tobramycin, and gentamicin are some of the common antibiotics used in these beads. Within 2-4 weeks, the beads may be replaced with cancellous bone graft.

Because two major aims of surgical treatment are resection of necrotic bone and thorough debridement of intraosseous and soft-tissue fistula, computed tomography (CT) is sometimes performed for the purpose of planning a surgical intervention and guiding surgery. Preoperatively, CT is helpful to characterize bone quality, demonstrate intraosseous fistula, and detect devitalized bone areas, or cortical defects that lead to soft-tissue sinus tracts. [2]

When osteomyelitis involves a fracture, it is also important to include a workup to be sure the fracture has healed. Antibiotic-impregnated beads may be used as an effective measure to maintain sterile dead space until a definitive surgical procedure can be performed.

In order to apply the Ilizarov method successfully and to prevent damage to vital nerves and blood vessels, preoperative planning is helpful with careful attention to "safe zones" during wire insertion. It is important to adjust the skin to prevent tension on the skin-wire interface. Correction of the deformity or lengthening is better achieved by appropriately constructing the Ilizarov frame. [40]

Ilizarov method

The Ilizarov method, developed by Ilizarov in 1951, promotes bone growth through distraction osteogenesis using a specialized device and systematic approach. This technique has facilitated limb lengthening, decreased the incidence of many complications, and decreased the level of surgical intervention necessary.

The Ilizarov method involves the use of a tissue-sparing cortical osteotomy-osteoclasis technique that preserves the osteogenic elements in the limb. To create a preliminary callus that can be lengthened, Ilizarov advocated a delay of several days before distraction is initiated. A high-frequency, small-step distraction rhythm permits regeneration of good-quality bone and less soft-tissue complications such as nerve and vessel injury. An advantage of using this procedure is that it minimizes the prevalence of nonunion and thus further bone grafting by producing good-quality bone formation.

The risk of repeat osteotomy and osteoclasis is also decreased owing to less-premature consolidation of the lengthened segment. [41] However, Ilizarov techniques are often not tolerated well by patients, and other options, including amputation, may be preferred.

The Ilizarov external fixator is a popular device that is composed of wires, fixation bolts, rings, threaded rods, hinges, and plates, together allowing customized assemblies. Although this apparatus is stiff for bending and torsion, it is less stiff for axial loading. This feature is thought to help promote osteogenesis. [40]

The Ilizarov method is based on the concept of "tension stress," in which gradual distraction stimulates bone production and neogenesis. The Ilizarov device is attached to the distal or proximal portion of the affected bone. Bone regenerates as the screw and wire mechanism moves the healthy bone fragment at a maximal rate of approximately 0.25 mm four times per day for an overall rate of 1 mm per day.

Gentle distraction allows bone formation and decreases the need for supplemental bone grafting and internal fixation. The distraction force permits tissue fibers and cells to become oriented in the same direction as the distraction vector, which is thought to mimic the process of natural bone growth. [40]

Nonunions, malunions, or defects of any length can be treated and may also be corrected by using the Ilizarov method. At the same time, the Ilizarov technique is labor-intensive and may require at least 8 months of treatment. In addition, the fixator pins can be uncomfortable and often become infected. Amputation is an option if reconstruction is not suitable.

Wound closure

To arrest infection, it is necessary to provide adequate soft-tissue coverage. [4] Over small soft-tissue defects, a split-thickness skin graft may be placed, whereas large soft-tissue defects may be covered with local muscle flaps and free vascularized muscle flaps. Rotation of a local muscle with its neurovascular supply must be possible anatomically for that procedure to be successful.

These flaps bring in a blood supply, which is important for host defense mechanisms, new bone regeneration, delivery of antibiotics, and healing. They also may be used in combination with antibiotics and surgical debridement of necrotic and infected tissues. The fibula and iliac crest are common donor sites for free flaps.

Adjunctive hyperbaric oxygen therapy

Adjunctive hyperbaric oxygen therapy can promote collagen production, angiogenesis, and healing in an ischemic or infected wound. [4]

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Complications

The Ilizarov technique is usually well tolerated by the patient, with little associated pain. A few complications that have been reported include pin-tract infections and cellulitis, flexion contractures above and below the frame, limb edema, and bone fragment rotation with malunion. [42]

During the course of treatment with the Ilizarov technique, patients have a high emotional and physical burdens. However, these symptoms improve, and patients are similar to the general population postoperatively. Appropriate patient counseling regarding the psychological impact of this treatment is needed. [43]

The complication rate may be decreased by future efforts to improve the Ilizarov method. [41]  Some goals include improving the technique to prevent pin-track infections and osteomyelitis, premature or delayed consolidation of bone, angular or axial deviation of the new bone, joint contracture or instability, neurovascular compromise, and psychological adjustment reactions.

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Long-Term Monitoring

After a corticotomy is made for bone lengthening, a latency period is required before distraction. Once distraction has begun using the Ilizarov technique, new bone should be apparent within 3-4 weeks. After the appropriate length is obtained or the angular deformity corrected, the apparatus remains in place until completion of the consolidation phase. During the postoperative period, it is necessary to adjust or modify the assembly, and the apparatus is removed when the goal is achieved. [40]

Because the apparatus may be in place for an extended period, even as long as 1 year, special postoperative considerations are important. [40] Pain management may be a challenge because of the duration of mild-to-moderate postoperative pain. For preventing flexion contractures of the surrounding joints, intensive physical therapy and splinting techniques are key elements. Successful treatment also requires psychological support and family counseling.

Problems to be particularly watchful for during the postoperative period include pin-track infections, premature or delayed consolidation, joint contractures, and pin breakage that may require replacement.

Imaging studies in the follow-up period are most useful in patients who have equivocal or worse clinical status at the end of therapy.

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