Acute & chronic osteomyelitis

Vivek Pandey Trauma, Sports injury Arthroscopy

Joint replacement unit

drvivekpandey.in

• Pain & swelling near the end of a long bone in an infant & child should be treated as acute osteomyelitis unless proved otherwise

Rutherford Morrison

• Definition

• Classification

• Etio-pathology

• Clinical features

• Investigations

• Treatment

• Complications

Acute osteomyelitis• Definition

Infection of bone and bone marrow

• More common in children

Classification “Based upon source”

1. Direct/ traumatic

2. Indirect/ haematogenous

Classification “Based upon Etiology”

1. Pyogenic

2. Tubercular

3. Fungal

4. Parasitic

Classification “Based upon Duration”

1. Acute : < 6 weeks2. Primary sub-acute: 6-12 weeks• Brodie’s abscess• Sclerosing osteomyelitis of Garre’s• Salmonella osteomyelitis (multifocal in

SCA)3. Chronic: >12 weeks

Predisposing factors• Infancy, children

• Boys > girls

• Poor nourishment

• Host response: immunosuppression/immunocompromised

• Sickle cell anaemia

• Trauma??

• Other sites of infection

Bacteriology• Staph. aureus****

• Str. pyogenes

• E. coli

• Pnemococci

• Pseudomonas in IV drug abuser

• Salmonella: multifocal, in SCA

Site

North sikkim ‘ 07

SiteCommonest

“Metaphyses of a long bone”

1. Hair pin loop of

capillaries

of metaphyses***

2. Relative lack of WBCs

3. High cell turnover

• Growth plate prevents spread of infection into joint

• Intracapsular physis leads to septic arthritis

Pathophysiology1. Stage of intraosseous abscess

2. Stage of subperiosteal abscess

3. Stage of sequestration & involucrum formation

Clinical features• Fever: may be normal/decreased in infant

• Dehydration

• Pain

• Local tenderness

• Swelling: fluctuant, tender

• Pseudo paralysis

• Joint free but may have sympathetic effusion

D/D

• Acute poliomyelitis

• Septic arthritis

• Ewing’s sarcoma

• Scurvy

• Haemarthrosis: known haemophiliac

Investigations• Blood: TC, DC, ESR, CRP

• Blood culture

Investigations• X-ray: “No findings till 2-3 weeks”

14 days – periosteal elevation

2-3 weeks – localized rarefaction

Investigations• Bone scan: “Earliest positive”

1. Tc 99**- sensitive

2. Gallium & Indium scan

WBC labelled

- more specific

Investigations• MRI: intramedullary abscess, edema**

• Bone aspiration with wide bore needle***: Gram stain, C/S

Investigations• CT: for sequestrum

“ Indicated in ch. Osteomyelitis”

Treatment1. General

2. Medical

3. Surgical

Treatment1. General• Antipyretics• Analgesics• IV fluids (correct dehydration)• Correct Anaemia• Splint/traction

- prevent deformity• Antiedema measures

- Limb elevation- Magsulf dressings

Treatment

< 48-72 hr presentation--Broad spectrum antibiotics covering G+, G- & anaerobes. (Inj. Cloxacillin+ Genta.+ Metro.)

--Later switch over to specific antibiotic, if any, according to C/S

**2 weeks IV + 4-6 weeks oral

2. Medical

Treatment.

> After 72 hrs / if it doesn’t responds to conservative treatment

Still high fever, pain, decreased

movement

Treatment.

• Decompression of medullary cavity and drainage of pus

Complications

Complications• Chronic osteomyelitis

• Septic arthritis

• Growth plate destruction leading to shortening (rarely lengthening), deformity

• Septicemia

• Pathological #

• Commonest site

• Commonest organism

• Role of x-ray

• Most sensitive

• Earliest investigations

• Medical F/B surgical

• DICTUM………….

Chronic osteomyelitis

PathophysiologyChronic infection

Bone becomes dead, infected granulation tissue surrounds it

Sequestrum

(dead, infected necrotic bone surrounded by granulation tissue)

• New bone formation stimulated around sequestrum known as Involucrum

• Involucrum has small fenestrations to let the pus & infected material leave the cavity known as Cloacae

• All this pus & infected material reaches the skin via a Sinus which is adherent to bone

Pathophysiology

sequestrum

involucrum

sequestrum

involucrum

Hallmark of chronic osteomyelitis

• Infected dead bone within a compromised soft tissue envelope.

-Infected foci within the bone are surrounded by sclerotic, relatively avascular bone

-covered by a thickened periosteum and scarred muscle and subcutaneous tissue.

• This avascular envelope of scar tissue leaves

“Systemic antibiotics essentially ineffective”

Clinical features• Chronically discharging sinus which is

fixed to underlying bone***

• Underlying bone- thickened, tender and irregular***

• Spicules of dead bone pieces may be discharged

Clinical features.• Thickened, discolored, scarred skin

• Nearby joint may be stiff

• Muscle wasting

• Constitutional features –

Rare except when there is acute exacerbation

Investigations1. X-ray****

2. Sinogram***

3. Biopsy**

4. Culture & sensitivity**

5. CBP,ESR, CRP*

6. CT, MRI*

Investigations• X-ray: 1.Thickened irregular cortex

2.Sequestrum (dense bone)

3.Involucrum

4.Lytic lesions

5.Periosteal

reaction

sequestrum

involucrum

Investigations

• CBP: May be normal except in acute

exacerbation

• ESR & CRP: may be elevated

• Culture & sensitivity:

Better to take from the cavity to know the original bacteria. Surface discharge is contaminated

Investigations

• Biopsy (Gold standard)

histological and microbiological evaluation of the infected bone.

Investigations

• Sinogram

For sinus tract

Origin & Path

• CT scan: good to assess sequestrum

• MRI: rarely

medullary edema, soft tissue condition

Treatment“Surgery is the mainstay of

treatment”

Surgical f/B Medical treatment

Principle:

1. Removal of dead bone 2. Removal of dead space

Treatment

Surgical procedure (3 S)**

1. Sinus tract excision2. Sequestrectomy

3. Saucerisation4. Curretage

Removal of dead bone & tissue

1. Excise sinus tract

2. Sequestrectomy: Remove dead bone

3. Saucerisation:

• Convert pitcher shaped cavity into a saucer

shape so that dead space is eliminated &

infected material can be constantly drained

• Dead space left can be filled by PMMA-gentamycin beads to deliver the antibiotic locally

4. Remove any implant

5. If bone appears weak/associated pathological fracture– apply external fixator

Medical Treatment• IV antibiotics for 2 weeks followed by 6

weeks of oral therapy according to C/S

Removal of dead space• Once this cavity is full of healthy

granulation tissue,

The cavity/dead space can be filled by

1.Bone graft

2.Muscle flap

3.Myocutaneous flap

4.Bone transport by ILIZAROV technique

Complications• Pathological fracture• Recurrence• Growth plate damage: deformity,

shortening• Septic arthritis• Squamous cell carcinoma of sinus tract• Amyloidosis• Septicemia