Debridement, Irrigation, and Decompression of the Bone for Chronic Osteomyelitis of the Distal Tibia and Active Sinuses

Abstract

Chronic osteomyelitis (COM) is a debilitating bone infection that presents a significant health burden in low- and middle-income countries. In children, it frequently results from delayed treatment of acute hematogenous infection. This case involves a 13-year-old male presenting with over one month of leg pain, difficulty walking, and three active draining sinus tracts along the medial distal tibia. Preoperative radiographs revealed a sequestrum involving nearly half of the distal tibia with an incomplete involucrum. Surgical management focused on thorough debridement and decompression. The procedure involved making an incision to connect the sinus tracts, performing a sequestrectomy to clear the medullary canal, and using a drill to decompress a Brodie’s abscess. Debridement was continued until healthy bleeding bone was observed. Following saline and iodine irrigation, a gentamicin solution was applied as a local antibiotic adjunct. This case highlights the importance of balancing radical debridement with the preservation of structural stability in resource-limited settings. Postoperatively, the patient received broad-spectrum antibiotics and was maintained on partial weight-bearing to allow the involucrum to mature.

Keywords

Bone infection; pediatric orthopaedics; debridement; washout.

Case Overview

Background

Chronic osteomyelitis (COM) is a debilitating infection of the bone and poses a significant burden in low- and middle-income countries. Globally, an estimated 12 million children are affected by osteomyelitis. In sub-Saharan Africa, the incidence of pediatric osteomyelitis is estimated to be approximately 43 to 200 per 100,000 children,¹ up to 20 times the incidence in high-income nations.² 

In children, COM often develops due to delayed diagnosis and inadequate management of acute hematogenous osteomyelitis, in which infection (most frequently due to S. aureus) enters the systemic circulation and seeds in bone.³ It can also occur following open fractures and soft tissue infections. The metaphyses of long bones are most frequently affected given their vascularity, where infection lodges in small venous sinusoids, leading to a localized inflammatory response that disrupts the periosteum and destroys bone.⁴ Osteomyelitis is termed “chronic” when inflammatory changes in the bone result in the formation of abscesses or sequestra (areas of dead bone),⁴ which typically takes at least 6 weeks. High intramedullary pressures from pus can lead to the spread of exudate through the subperiosteal space, cutting off essential blood supply to the bone, and can also break through the skin through the development of sinus tracts.

Surgical debridement and stabilization of the bone are required to prevent pathological fractures due to weakened bone.⁵ Delayed debridement leads to widening of the sequestrum, resulting in larger bone defects and soft tissue damage that can be difficult for patients and surgeons to manage without specialized knowledge in limb reconstruction and orthoplastics.

Focused History of the Patient

A 13-year-old male patient presented to a district hospital in rural Malawi with over one month of left lower leg pain and difficulty walking. There was no other known medical or surgical history.

Physical Exam

The patient was generally well-appearing and breathing comfortably. The left foot was warm and well-perfused. The patient was tender to palpation along the left medial distal tibia. There were three small skin defects in the medial aspect of the distal tibia where the patient was found to have draining sinus tracts. Sensation was intact to light touch across all dermatomes of the left leg and foot, with no report of numbness or paresthesias. Muscle tone was normal without clonus. There was full active range of motion with 5/5 muscle strength in the major lower extremity muscle groups. The patient walked with a significant limp due to pain with weightbearing on the left side.

Imaging

Standard AP and lateral radiographs are an essential first step in the work-up of suspected osteomyelitis. However, their sensitivity is low in early stages of the disease, as most bony changes cannot be observed within the first ten days of disease.⁷ In the case of this patient, early x-rays were unavailable. If available, magnetic resonance imaging (MRI) should be pursued in the case of negative or equivocal radiographic findings if clinical suspicion of osteomyelitis is high.⁸ At the subacute stage, hallmark changes include Brodie abscesses, which are oval-shaped lytic lesions that typically occur in the metaphysis of long bones, most commonly in the tibia.⁹ Once the disease has progressed to COM, radiographs may demonstrate changes including bone loss, reactive sclerosis, sequestra, involucrum, and associated soft tissue changes including swelling or the presence of gas in the soft tissues. If sequestra or involucrum are present, CT and MRI can help to assess the extent of such findings for surgical planning.

Multiple classification schemes to assess the severity of COM exist, including the Cierny-Mader classification system, the Beit CURE classification system, and the Penny Classification. The Cierny-Mader classification system characterizes the patient based on the anatomic spread of the osteomyelitis and the degree to which the patient’s immune system is compromised, and is especially useful for the classification of adult osteomyelitis.¹⁰ The Beit CURE classification system (developed at the Beit CURE Children’s Hospital in Malawi) divides the condition into three main types based on radiographic findings and is particularly useful for hematogenous COM in children, who have open physes and are more likely to develop a robust involucrum unlike adults.¹¹ In our patient, the presence of sequestrum with incompletely formed involucrum and lack of physeal involvement would classify them as a B4 using the Beit CURE classification system (Figure 1). The Penny classification system broadly classifies the disease into one of five categories such as typical, atrophic, and sclerotic based on radiographic findings, and provides suggested treatments.⁵

Figure 1. AP (A) and lateral (B) preoperative radiographs of the distal tibia demonstrating findings suggestive of chronic osteomyelitis.

Natural History

In the acute phase, clinical signs of hematogenous osteomyelitis reflect systemic infection, with typical signs including chills, fevers, malaise, and positive blood cultures. Once the infection has seeded in long bones and systemic symptoms have subsided, clinical findings are more localized to the area of seeding and include bone tenderness, local swelling, and in more severe cases, development of sinus tracts.⁶

Untreated COM in children can lead to significant complications including pathologic fracture,¹² septic arthritis, segmental damage, and physeal destruction that can cause leg length discrepancy or angular deformity.⁵ An important long-term risk of COM is the malignant transformation (most commonly to squamous cell carcinoma) of the cells lining sinus tracts.¹³ While rare, occurring in less than 1% of cases, surgeons should be aware of the risk, as definitive treatment of SCC in resource-limited settings may involve amputation.

Options for Treatment

In resource-limited settings, empiric therapy with antibiotics should be started in cases of suspected acute pediatric hematogenous osteomyelitis even if signs are not visible on radiography. Blood cultures should always be obtained prior to the commencement of antibiotics. Obtaining a C-reactive protein level at baseline, though not specific for diagnosing osteomyelitis, can be a helpful adjunct for serial monitoring.

If abscesses or a sequestrum are present, incision and drainage of pus, sequestrectomy, and thorough debridement of damaged bone are required for clearing the local collection of disease and preventing further bone loss. There are no conservative therapies to treat COM, and delaying surgical debridement can lead to severe disability, pain, and functional impairment.

Rationale for Treatment

In this patient, as in any patient with COM, the goal of surgical treatment is to remove as much of the affected tissues as possible while maintaining adequate bone stability for physiological functioning.¹⁴ Inadequate debridement which leaves behind avascularized dead bone or scar tissue can become an ideal nidus for bacterial regrowth. Therefore, surgery must be carefully planned to achieve wide margins around infected tissue. In addition to irrigation and debridement, treatment may include decompressing the bone by drilling holes into the cortex to decrease pressure in the medullary cavity where pus and inflammation have accumulated. Decreasing pressure in the medullary cavity decreases the likelihood of cutting off blood supply to the bone and can help prevent further osteonecrosis, and can also prevent the formation of sinus tracts if they have not already formed. 

Management of the remaining dead space after excision of infected tissue is varied based on the size of the bone defect and the surgeon’s skill. In resource-limited settings where formal negative pressure wound therapy (NPWT) is frequently unavailable due to prohibitively high costs, improved vacuum therapies can be utilized to continually apply negative pressure to the wound and promote wound healing. The usage of local antibiotic delivery mechanisms including spacers, beads,¹⁵ and loaded bone cement¹⁶ has been shown to be useful adjuncts, providing high doses locally while reducing systemic toxicity. Whereas smaller bone defects can be managed with acute shortening, larger bone defects may require bone transport or bone grafting, and may need to be coupled with rotational flap coverage.

Special Considerations

In resource-limited settings globally, surgeons must plan a thorough preoperative workup of patients to optimize patients prior to surgery. This includes assessing nutritional status, immune status, and lifestyle factors by obtaining hemoglobin, albumin, HIV status, fingerstick glucose, and malaria testing. A thorough preoperative evaluation can help to reduce complications from significant blood loss and poor capacity to heal. Furthermore, in tuberculosis-endemic areas, surgeons must always consider TB as the pathogen causing osteomyelitis. While preoperative PCR testing can help risk-stratify patients, a confirmatory intraoperative biopsy and culture is recommended for all patients. Sinus tract cultures are not recommended as they are frequently contaminated with mixed flora. Particularly in places where laboratory capacity to perform cultures is limited, such as in this case, patients should be started on empiric, broad-spectrum antibiotics as soon as possible.

Discussion

This case provides an example of surgical management of pediatric COM of the distal tibia, a very common anatomic location to be affected by this disease. The case features a patient with three active sinuses on the medial side of the distal tibia, and a sequestrum that affected nearly half of the distal tibia, without a fully formed involucrum. It offers a real-world example of the decisions made by surgeons regarding how much to debride to reduce the risk of reinfection and how much bone to retain for stability. It also highlights some of the constraints that are frequently present in low- and middle-income countries globally, including the lack of advanced imaging or antibiotic cement. 

The surgical procedure started with an incision over the medial soft tissues connecting the sinus tracts overlying the bone. Dissection was done until bone was visible, with care taken to minimize the extent of periosteal stripping. Thorough debridement of the sequestrum and the medullary canal was done using a curette and rongeur, minimizing damage to the involucrum. Biopsies of the sequestrum and tissue cultures were obtained. A drill was used to decompress the Brodie’s abscess. Debridement was continued until the “paprika sign” was observed, indicating punctate bleeding from the Haversian canals characteristic of healthy living bone. The bone was thoroughly irrigated using low-pressure saline solution in a syringe, followed by iodine. The iodine was left in the bone for a few minutes and then washed out with saline. Since antibiotic-laden bone cement or beads were unavailable, a small amount of gentamicin solution was poured into the wound. The wound edges were cleaned with a scalpel and approximated loosely with simple interrupted sutures using nonbraided, nonabsorbable suture with the intention of leaving enough space for any remaining pus to drain and prevent the development of new sinus tracts.

The patient remained on broad-spectrum antibiotics (ceftriaxone and vancomycin) until the cultures with sensitivities resulted. Given the relatively small defect in the medial tibia of approximately 5 cm, the patient was instructed to be partially weight-bearing for at least 6 weeks until the involucrum had matured, precluding the need for complex bone reconstruction. 

Historically, COM was often treated with radical sequestrectomy,⁵ or even amputation. More recently, the field has shifted to a more biological approach with special emphasis on creating a viable environment for host healing.¹⁷ While some authors recommend early sequestrectomy, others prefer to wait until an involucrum has at least partially formed prior to performing a sequestrectomy to improve the chances of bone healing and minimize the risk of segmental bone loss and significant deformity.⁵

Equipment

No special equipment was utilized in this procedure.

Disclosures

Kiran J. Agarwal‑Harding serves as a Section Editor at JOMI for Orthopaedic Surgery and has not been involved in the editorial processing of this article in any capacity other than as an author.

We report no other conflicts of interest, financial relationships, funding, sponsorship, equipment support, or other relationships that could be perceived to influence the content of this article.

Statement of Consent

The legal guardian of the patient referred to in this video article has given their informed consent for their child to be filmed and is aware that information and images will be published online.

Acknowledgments

We would like to acknowledge the team from the Mzuzu Orthopedic Support and Training program, including the local operating room staff (nurses, transport staff, anesthesia clinical officers), local orthopaedic surgery team (Dr. Bitiel Banda and orthopaedic clinical officers), program staff (Gomezgani Jenda), and the Foundation for Orthopaedic Trauma who funded this program. We would also like to sincerely thank the patient and their guardian, who agreed to allow for filming and dissemination of this procedure and its details.