Chronic bone infections in adults

by Thomas Hilton, Mohammed Daoub, Len Marais, Nando Ferreira & Luan Nieuwoudt

Learning objectives

  1. Define acute osteomyelitis.
  2. Recognise a patient presenting with acute bone infection.
  3. Know the management of acute bone infections.
  4. Exclude immunocompromise and assess nutritional status.


Infection of the bone or osteitis/osteomyelitis (OM) can be divided into the subtypes - acute, sub-acute and chronic. According to the temporal classification, acute OM has a duration of under two weeks, sub-acute OM one to three months and chronic for more than three months. Clinically, acute osteomyelitis is characterised by the absence of sequestrum, sub-acute osteomyelitis by Brodie’s bone abscess and chronic osteomyelitis by sequestra and involucrum or foreign material (such as orthopaedic implants).


Risk factors for poor prognosis

Despite surgical debridement and long-term antibiotics, the recurrence rate of chronic OM in adults can still be as high as 30%. Certain risk factors lead to poor prognosis (see table).

Risk factors poor prognosis
Previous surgery or trauma
Corticosteroid use
Diabetes Mellitus
IV drug abuse
Poor vascular supply
Peripheral neuropathy
Chronic renal failure/Dialysis


Cierny and Mader (1984) classified chronic OM according to the infection’s anatomic distribution and the host’s physiological status. The anatomic areas are:

  1. Medullary (bone marrow only)
  2. Superficial (cortex)
  3. Localised (medulla and cortex, stable)
  4. Diffuse (medulla and cortex, unstable)

The host is divided into:
A - Healthy (No comorbidities)
BL: - Local compromise
BS - Systemic compromise
C - Poor host status (surgical treatment carries higher morbidity than the disease itself)



The duration and severity of symptoms such as pain, pus drainage or functional impairment that is the inability to walk and so on, must be established. Find out about previous treatment or surgery and comorbidities


Evaluate vital signs (fever, tachycardia, tachypnoea and hypotension suggest sepsis) and signs of systemic disease.


Erythema, tenderness and oedema are commonly seen. Discharge or a draining sinus is common in chronic OM. The soft tissue condition including scarring or Lipodermatosclerosis, abscess formation or cellulitis must be noted.
The vascular status of the limb must be assessed.
Any skeletal instability, pathological fracture or fracture non-union must be noted. The range of motion, limping or being unable to bear weight because of pain are signs of instability.

Sinus formation in chronic OM
Sinus formation in chronic OM


AP and lateral views of the affected limb often show bone resorption with a sclerotic rim around the infected bone, disuse osteopenia, periosteal reaction, lucency (lysis around hardware/ implants) and sequestrum and involucrum formation.

CT scan and MRI:

Valuable in diagnosis and surgical planning by identifying necrotic bone.

Laboratory analysis:

WCC, ESR, CRP may not always be raised in chronic osteomyelitis.

Staging of the host:

Identification of causative organisms:


The management of chronic osteomyelitis is complex, and cases should ideally be referred to orthopaedic units specialising in treating chronic bone infections.

Optimisation of the patient:

This should entail the cessation of smoking and alcohol abuse, nutritional support (high protein diet for patients with low albumin level), blood sugar control and anti-retroviral therapy for HIV+ve patients.

In patients with acute flare-ups (cellulitis or abscess formation), systemic antibiotics are required to control the infection. Definitive surgery is typically delayed until the soft tissue condition improves.

Local treatment:

Colostomy bags over the sinus protect the skin from excoriation. Acute abscess formation requires urgent incision and drainage with tissue sampling for MCS, followed by directed intravenous antibiotics.


During surgery, a tissue biopsy for culture and microscopy is taken, all necrotic and devitalised tissue is debrided, and implants are removed. Skeletal stability is typically achieved by external fixation. Soft tissue reconstruction is then performed, which may involve plastic surgery.

Following surgery, empiric intravenous antibiotics are given until the culture results become available, after which directed oral antibiotics are given for six weeks. The antibiotic regime should include agents that exhibit appropriate activity against biofilm-based organisms.

In severe cases, surgical reconstruction may not be possible, and amputation may need to be considered


Chronic suppression with antibiotics may be useful for patients where surgery is not feasible. This requires an opinion from a bone infection unit.


Cierny G, Mader JT, Penninck JJ. A clinical staging system for adult osteomyelitis. Contemporary Orthopaedics 1985;10:17-37.

Cierny G, Mader JT. Adult chronic osteomyelitis.Orthopedics 1984;7:1557–64.

Lalani T, Schmitt SK. Osteomyelitis in adults: Clinical manifestations and diagnosis.

Marais LC, Ferreira N, Aldous C, Le Roux TL. The classification of chronic osteomyelitis. SA Orthopaedic Journal. 2014 Mar;13(1):22–8.

Miller MD, Thompson SR. Miller’s review of Orthopaedics, 7th edition

Mthethwa PG, Marais LC. The microbiology of chronic osteomyelitis in the developing world. S Afr J Orthop 2017; 16(2): 39–45.

Osmon, DR, Tande, AJ. Osteomyelitis in adults: Treatment. 5.2.21)

Solomon L, Warwick D, Nayagam S. Apley’s System of Orthopaedics and Fractures (9th edition). CRCpress, 2010

Spritzer, CE: Approach to imaging modalities in the setting of suspected nonvertebral osteomyelitis. 5.2.21)