Acute & chronic osteomyelitis

Vivek Pandey Trauma, Sports injury Arthroscopy Joint replacement unit

drvivekpandey.in

Rutherford Morrison

• Pain & swelling near the end of a long bone in an infant & child should be treated as acute osteomyelitis unless proved otherwise • 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 weeks 2. 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 Site Commonest “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 Pathophysiology 1. 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” Treatment 1. General 2. Medical 3. Surgical Treatment 1. General • Antipyretics • Analgesics • IV fluids (correct dehydration) • Correct Anaemia • Splint/traction - prevent deformity • Antiedema measures - Limb elevation - Magsulf dressings Treatment 2. Medical < 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 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 Pathophysiology Chronic infection

Bone becomes dead, infected granulation tissue surrounds it

Sequestrum (dead, infected necrotic bone surrounded by granulation tissue) Pathophysiology • 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

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

Investigations 1. X-ray**** 2. Sinogram*** 3. Biopsy** 4. Culture & sensitivity** 5. CBP,ESR, CRP* 6. CT, MRI* Investigations • X-ray: sequestrum 1.Thickened irregular cortex 2.Sequestrum (dense bone) involucrum 3.Involucrum 4.Lytic lesions 5.Periosteal reaction

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 excision 2. Sequestrectomy 3. Saucerisation 4. 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