Infections in Orthopedics - how to mange

Septic arthritis & Osteomyelitis

1. Infections in Orthopedics Rohan Jayawardena Registrar in General Surgery NHSL 29/10/2020

2. Septic arthritis Osteomyelitis Acute Subacute Chronic

3. Septic Arthritis Infection in a joint. Involvement of synovial joint. Exudates+Bacterial toxins+Increase intraarticular pressure+Reduce blood flow+Inflammatory cells of own – damage the cartilage. If interventions delay >6hrs- will damage the cartilage Epidemiology – In 2012 – 16,000 emmergency dept admissions in USA Joint involvement – Knee – 50% Hip > Shoulder> Elbow> Ankle> Sternoclavicular joint Commonest in children Found in IV drug users

4. Mechanism of infection Children Adults Old age Haematogenous Local Haematogenous Pre – existing arthritis Trauma/ Surgery/ Injection Skin/ Soft tissue infection IV drug use/ Indwelling catheters Immunosuppression Haematogenous

5. Microbiology Neonates – S. a ureus (Most common) E. coli/group B strep. / Gram (-) bacilli < 5years – H. influenzae (prior to vaccine era) S. aureus > 5 years – S. aureus

6. Organisms in adults

7. Clinical manifestations Joint swelling + Pain – Acute onset Fever > 38.5 o C 80% Restricted movements Limping/ non Wt bearing – Mainly in children Features of inflammation Features of systemic infection (EJ – swelling mainly comes in humerus. Not on forearm. Because forearm deep fascia prevents swelling)

8. DD Septic bursitis (Prepatellar) OA Crystal induced arthritis Cellulitis Transient synovitis Tumors - Leukaemia

9. Investigations Inflammatory markers Blood culture - Positive in 50% of cases in haematogenous spread Imaging – X ray – Joint space widening due to fluid ( as baseline/ exclude # & bone tumors) - USS – Echogenic particles Essential for hip because swelling is not visible To differentiate SA from osteomyelitis - MRI – Gold standard Joint fluid aspirate – Full report - Cytology – malignancy suspected - Culture Gram stain Aerobic/anerobic

10. Intepretation of Joint Fluid Aspirate Appearance – Purulent WBC > 50,000 Native joint Polymorphs > 75% Protein – High

11. Interpretation in prosthetic joint infection

12. Treatment Intially emperical antibiotics – IV Flucloxacillin 2g 6h Allergy < 5yrs – Add Cefotaxime/ Ceftriaxone Clindamycin/ Vancomycin/ Suspected Gram (-) – Add Cefotaxime/ Ceftriaxone Teicoplanin MRSA risk - Vancomycin Then treat according to the cultures Duration – Neonates – IV AB 3 weeks Children – total 3 weeks with minimum 3 days IV AB (Cont. IV AB until CRP<20 + Fever settles) Adults – total 4 weeks with minimum 2 weeks IV AB

13. Irrigation & drianage of joint - USS guided aspiration – Mainly in hip. After on aspiration can see the response. If not need arthrotomy - Arthroscopy - Open – KJ – Left lateral parapatella approach. Wash the joint until it become clear Don’t close capsule to prevent intracapsular pressure Synovial biopsy always - histology Device related – Anterior approach - HJ – Anterior approach Splinting the affected limb – KJ- B/S to prevent pain & further HJ – Traction damage to the joint Pain management – Pharmocological (Analgesics) & Mechanical (Splinting) Mobilization – Slowly. Untill patient can weight bear Rehabilitation

14. In children with cellulitis – No history of prick injury/ trauma Better to treat as SA unless proven other wise Transient synovitis is diagnosis of exclusion which can be managed with NSAID SA is always clinical diagnosis If USS delays arthrotomy better to go ahead with Sx because (-) arthrotomy is better than delaying arthrotomy

15. Complications Arthritis Fibrous ankylosis Osteomyelitis Metastatic abscess Long term – AVN Deformed sublux joint

16. Osteomyelitis Infection of bone charachterized by progressive inflammatory destruction of bone & apposition of new bone Classification according to timing - Acute – within 2 weeks - Subacute – within one to several months - Chronic – after several months

17. Mechanism of spread Haematogenous – Common in children (because reduce blood flow at metaphysial region causes stagnation of organisms) - Vertebrae – most common site in adults - S.aureus – most common organism Contiguous spread – Previous surgery/trauma/wounds/poor vascularity - Most common bacterial (can be MB/fungal) Direct inoculation – Trauma Hx

18. Microbiology Same as septic arthriis

19. Clinical manifestations Features of systemeic infection Pain Limp Draining sinus tracts Probing to bone test

20. Investigations Inflammatory markers – WBC – elevated in 1/3 of AO - ESR – elevated in both – 90% - decrease after treatment - (+) prognosis - CRP – most sensitive – elevated in 97% - decrease faster than ESR in successfully treated patients Blood culture Sinus tract cultures – not reliable in guiding AB therapy Culture of bone – gold standard for guiding AB therapy Histology

21. Imaging - X ray – Appears after 2 weeks - Acute – No much changes - Chronic – Bone lucency/ sclerotic rim/ osteopenia Sequestrum Involucrum Necrotic bone seperates from viable bone New bone formation

22. Brodie abscess – Region of suppuration & necrosis encapsulated by granulation tissue within a rim of sclerotic bone - Subacute - Metaphysis of long bones - Usually haematogenous origin

23. USS CT Bone scan – High sensitivity + Low specificity MRI – Gold standard Highly sensitive Changes appears before 2 weeks Identify BM & soft tissue involvement, ischemia

24. Treatment Antibiotics – AOM – similar to SA No emperical AB for COM Bone biopsies should be obtain before commencing AB If AB already started stop for 2/52. Rpt cultures. Then decide on AB Surgical management - Irrigation & debridement – Necrotic tissue/ Sequestrum Dead space managemnt – Bone grafts/ Flaps/ PMMA/ VAC/ Fixation Amputation Splinting the affected limb Analgesics Mobilization Rehabilitation

25. Complications Sinus tract formation Soft tissue infection Abscess SA Bone deformity Fractures Malignancy – 1% in COM Most common SCC – Marjolin’s ulcer

26. Refferences Uptodate 2020 – Septic arthritis in adults/ Bacterial arthritis in children & infants/ Non vertebral osteomyelitis in adults https://www.orthobullets.com/trauma/1058/septic-arthritis--adult https://www.orthobullets.com/trauma/1057/osteomyelitis- - adult https://emedicine.medscape.com/article/236299-overview/septicarthritis Empirical and prophylactic use of antimicrobials- National guidelines -2016 - https:// slmicrobiology.lk /antibiotic-guidelines-2016/

27. Thank you