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Osteomyelitis is an infection of bone or bone marrow, often caused by bacteria or mycobacteria. In chronic refractory cases, standard treatment with surgical debridement and targeted antibiotics frequently fails due to compromised blood flow and poor antibiotic penetration. This is particularly concerning in infections affecting the spine, skull, or sternum, where the risk of complications increases significantly. Hyperbaric oxygen (HBO) therapy serves as an adjunctive intervention that enhances tissue oxygenation and supports antimicrobial activity, offering potential benefits for patients with osteomyelitis who are unresponsive to conventional treatment. This activity presents an in-depth review of the pathophysiology, diagnosis, and management of chronic refractory osteomyelitis, with emphasis on the role of HBO therapy. Evidence supporting the use of HBO as part of an interprofessional treatment strategy is examined, highlighting its impact on infection control and tissue healing. The program also outlines the indications for early HBO consultation and underscores the value of collaboration among infectious disease specialists, surgeons, and hyperbaric medicine teams. By integrating current clinical guidelines and treatment approaches, this activity enhances provider understanding of advanced care options for complex osteomyelitis cases. Objectives: Differentiate between acute, chronic, and refractory osteomyelitis to guide appropriate treatment strategies. Screen patients for risk factors that increase susceptibility to osteomyelitis, such as diabetes or recent surgery. Implement culture-directed antibiotic therapy based on pathogen identification and resistance patterns. Communicate interprofessional team strategies for improving care coordination and communication to advance the treatment of chronic osteomyelitis and improve outcomes. Access free multiple choice questions on this topic.

Osteomyelitis is an infection of the bone or marrow caused by bacteria or mycobacteria. This condition is challenging to treat due to the relative lack of blood vessels in bone, and many antimicrobials do not penetrate bone well. Refractory osteomyelitis is a chronic osteomyelitis that does not respond to (or returns after) appropriate treatment. Patients presenting with osteomyelitis to the spine, skull, or sternum have a high risk for morbidity and mortality from this infection. The standard treatment for chronic and refractory osteomyelitis includes surgical debridement and culture-directed antibiotics. Although no randomized trials of hyperbaric oxygen therapy for osteomyelitis have been conducted, hyperbaric oxygen treatments are considered a Class II recommendation by the American Heart Association (AHA) for treating chronic, refractory osteomyelitis.[1] In patients with Wagner grade 3 or 4 diabetic foot ulcers with osteomyelitis, adjunctive hyperbaric oxygen therapy is an AHA Class I intervention. Recent study results have postulated that over 20% of patients presenting to wound care centers for treatment of Wagner 3 diabetic foot ulcers already have osteomyelitis. Infection in bone is one of the causes of a nonhealing wound and should be suspected and tested for as soon as possible when a patient presents with a chronic, nonhealing wound.[1][2]

Staphylococcus and Streptococcus species are the most common organisms isolated in infants and children after hematogenous spread. In adults, Staphylococcus aureus is usually isolated. Infection can be caused by hematogenous spread or by direct inoculation of microorganisms into bone. Intravenous drug abuse has been linked to hematogenous osteomyelitis involving the long bones or the vertebrae.[3][4] Chronic refractory osteomyelitis is a subset of osteomyelitis that does not respond to standard antibiotic courses and surgical debridement. To be considered "chronic" and "refractory," most sources state that the infection must have been under appropriate culture-directed antibiotic therapy and surgical debridement as warranted for at least 6 weeks without improvement or healing. One problem commonly seen in wound clinics is the patient who, due to nonadherence with medical treatment or a lack of awareness on the part of the treating clinician, receives an insufficient course of antibiotic therapy or lacks follow-up imaging and laboratory work to assess the response to treatment. These patients invariably return months later with a reopened wound or a draining sinus, as the body attempts to rid itself of the indolent infection in the bone.

Approximately 1 in 675 United States hospital admissions annually (approximately 50,000 cases annually) are due to osteomyelitis. Patients with diabetes, intravenous drug abusers, and other immunocompromised individuals are at increased risk for osteomyelitis. Post-traumatic osteomyelitis accounts for almost 50% of cases. Other major causes include neuropathy (mostly in diabetics) and hematogenous seeding (primarily seen in children).[5][6] Overall, resolution and healing rates for primary osteomyelitis treated with surgery and antibiotics range between 35% and 100%. Therefore, 70% and 80% of patients treated for primary osteomyelitis are cured. Long-term recurrence rates of osteomyelitis can vary between 20% and 30%. When appropriate medical and surgical interventions fail (or are contraindicated), the infection progresses or recurs, or the infection is associated with high morbidity and mortality, adjunctive hyperbaric oxygen treatments should be considered.[7]

S aureus is the most common pathogen cultured in osteomyelitis. Osteomyelitis is classified according to the Cierny-Mader classification: Stage 1: Medullary osteomyelitis (confined to the medullary cavity of the bone) Stage 2: Superficial cortical bone infection (most often results from direct inoculation or contiguous wound infection) Stage 3: Localized osteomyelitis (usually involves both cortical and medullary bone) Stage 4: Diffuse osteomyelitis (involves the entire thickness of the bone and results in structural instability, such as with an infected nonunion fracture)

Most infectious disease specialists advocate obtaining a bone culture from the site of the infection to treat with culture-directed therapy. Bone is sometimes visible or palpable in chronic wounds and can easily be obtained in the clinic using a rongeur. For deeper wounds or when bone cannot be obtained in the clinic, patients require referral to either surgery or interventional radiology to obtain a specimen for Gram stain, acid-fast bacillus culture, and sensitivity testing.

Many patients treated for chronic nonhealing wounds have underlying osteomyelitis as a contributing factor to impaired healing. Wounds that fail to close, close but reopen, have draining sinuses, or occur over areas where patients may have implanted hardware warrant a high index of suspicion for osteomyelitis. Bone infection in and around total joint prostheses can have catastrophic outcomes.

Laboratory tests, such as the erythrocyte sedimentation rate and C-reactive protein, should be obtained. If these levels are elevated, the patient is likely to have osteomyelitis. Magnetic resonance imaging is the gold standard for imaging osteomyelitis, as osteomyelitis often does not appear on plain film radiographs. A bone biopsy should be obtained to facilitate culture-directed antibiotics. An interprofessional team consisting of a surgeon, infectious disease specialist, and wound and hyperbaric medicine specialist is often needed to manage these cases effectively.

Surgical debridement and culture-directed antibiotics are the mainstays of treatment for chronic osteomyelitis. For patients who do not respond to appropriate therapy for 4 to 6 weeks, the diagnosis of chronic refractory osteomyelitis becomes appropriate. These patients should be referred for adjunctive hyperbaric oxygen therapy. Hyperbaric oxygen improves the penetration of certain antibiotics (cephalosporins and aminoglycosides) into bone and stimulates osteogenesis. Mader and Niinikoski showed that infected bone has a decreased oxygen content. During treatment, hyperbaric oxygen therapy increases the oxygen content to normal or above-normal levels. Leukocyte-mediated killing of gram-positive organisms such as S aureus and certain gram-negative bacteria is enhanced by increasing the oxygen content of infected bone through hyperbaric oxygen therapy. The transport of antibiotics such as aminoglycosides and cephalosporins into the infected bone is improved and increased with adjunctive hyperbaric oxygen treatment.[8][9] In patients for whom hardware removal or surgical debridement is not feasible, a trial of hyperbaric oxygen therapy combined with antibiotics should be considered before pursuing more aggressive surgical intervention.[1] Treatment is typically performed once a day for 90 to 120 minutes, using 100% oxygen at 2 to 3 atmospheres absolute pressure, along with appropriate antibiotic therapy. Usually, 20 to 40 HBO2 sessions are needed to resolve the infection. During cases where improvement or recurrence is seen, modification of antibiotics and surgical intervention should be considered. Hyperbaric oxygen may still be used after additional interventions, particularly if the infection remains refractory.[1]

The differential diagnoses for hyperbaric treatment of chronic refractory osteomyelitis include the following: Charcot joint Cellulitis Ewing sarcoma Giant cell tumour Gout and pseudogout Infectious arthritis Rheumatoid arthritis Septic arthritis Sickle cell anemia

Patients diagnosed promptly can be treated with appropriate culture-directed antibiotic therapy, surgical debridement (if indicated), and regular local wound care. Most patients can be treated entirely to the point of wound closure. Those with uncontrolled diabetes or other comorbidities tend to have poorer outcomes. Long-term treatment and follow-up care must be emphasized to the patient, as a multidisciplinary treatment protocol is essential.[10] Patients who complete hyperbaric oxygen therapy have a significantly greater likelihood of improvement in chronic osteomyelitis compared with those who initiate but do not complete therapy. Diabetes and congestive heart failure increase the probability of amputation.[11]

The most significant complication is failure to have a high index of suspicion and not making the diagnosis promptly. This can lead to the patient developing serious wound problems and can lead to major amputation when a foot or lower limb is involved.

Patients with diabetes should be taught to seek care for any wound as soon as it is identified, to consult a podiatrist regularly for diabetic foot care, and to schedule regular visits with their primary care clinician and endocrinologist. Reasonable glycemic control prevents infection and the loss of function of the white blood cells, which can lead to infections in patients with poorly controlled diabetes.

Osteomyelitis is a common and potentially devastating complication of postoperative, traumatic, or chronic wounds. Patients with diabetes mellitus, peripheral neuropathy, and foot ulcers are at high risk for osteomyelitis, as are those who abuse intravenous drugs. Clinicians must have a high index of suspicion and order appropriate lab tests and diagnostic imaging studies as soon as a wound does not respond to standard treatment in a timely fashion. Any diabetic foot wound that does not improve with 4 weeks of standard wound care, including debridement and appropriate dressings, should be checked for osteomyelitis. Results from a recent study support this, noting that adding HBO treatment to foot ulcers with chronic osteomyelitis achieved an 80% or greater resolution rate.[12][13][14][15][16] Chronic refractory osteomyelitis is diagnosed after an infection has not shown improvement or resolution after 4 to 6 weeks of adequate and appropriate surgical debridement and culture-directed antibiotics. Adding adjunctive hyperbaric oxygen treatment to the regimen is appropriate at that point. Patients are typically treated at 2.4 atmospheres absolute for 90 minutes, with 5-minute air breaks every 30 minutes, over 40 to 60 treatment sessions. The erythrocyte sedimentation rate and C-reactive protein should be measured every 4 to 6 weeks during treatment to assess response. These levels should fall to normal with adequate culture-directed antibiotic therapy. Intravenous antibiotics are often needed for 6 weeks or more.

An interprofessional team is essential for effectively managing osteomyelitis. This team should include specialists in wound and hyperbaric medicine, podiatry, general surgery, vascular surgery, interventional radiology, and infectious diseases. Osteomyelitis is typically treated with intravenous antibiotics; however, chronic or recalcitrant cases may be managed with HBO therapy. Although HBO therapy is not a substitute for antibiotics, it serves as an adjunctive treatment. The limited cases indicate that HBO therapy can help improve healing. Osteomyelitis, as well as other infections, increases the risk of cardiovascular disease and its associated events. The results from a large study showed that the use of HBO for chronic osteomyelitis was associated with lower 1-year mortality than those treated without HBO.[17]