Aetiology, pathology and management of osteomyelitis

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1. AETIOLOGY,PATHOLOGY AND MANAGEMENT OF OSTEOMYELITIS SANUSI A.A DEPT OF ORTHOPAEDICS AND TRAUMA JUTH

2. OUTLINE Introduction Definition Statement of surgical importance Epidemiology Relevant physiologic anatomy Classification Aetiology Microbiology Susceptibility/predisposition Pathogenesis

3. OUTLINE Pathology Inflammation Suppuration Necrosis New bone formation Resolution / chronicity Management Diagnosis History Symptoms Physical examination Investigations Treatment

4. OUTLINE Complications Peculiarities Conclusion References

5. INTRODUCTION Definition Osteomyelitis is an inflammation of bone and marrow caused by an infecting organism Statement of surgical importance It is one of the most difficult and challenging problems encountered in orthopaedics It can frustrate the best effort of orthopaedic surgeons

6. INTRODUCTION Epidemiology Worldwide, childhood acute haematogenous osteomyelitis is commoner Changing trends in the developed world Incidence <3/100,000 in Europe 8 cases per 100,000 children/year by POSNA Much higher among less affluent populations Male: female 2:1 Commonly affects the long bones Lower limbs > upper limbs

7. INTRODUCTION Relevant physiologic anatomy Penetration of physeal cartilage by metaphyseal vessels in the first 6-9 months of life Nutrient arterial system Hairpin bend Reduced oxygen tension Decreased phagocytic and reticuloendethelial function Rapid growth at metaphyseal region

8. Schematic representation of the blood supply to a long bone

9. Microcirculation of the metaphysis predisposes it to sludging and infection

10. INTRODUCTION- CLASSIFICATION The duration Acute Sub-acute Chronic Mechanism of infection Exogenous Haematogenous The type of infecting organism Pyogenic Non pyogenic

11. AETIOLOGY Microbiology Acute osteomyelitis Neonate and infants Group B streptococcus, Staphylococcus aureus Escherichia coli Older children Staph aureus Streptococcus pyogens Haemophilus influenzae Kingella kingae Adults Staphylococcus epidermidis S. aureus Pseudomonas aeruginosa E. coli

12. AETIOLOGY Microbiology Acute osteomyelitis Sickle cell patients Staph aureus Salmonella spp Immunocompromised /iv drug users Staph aureus H. influenzae

13. AETIOLOGY Microbiology Chronic osteomyelitis Usually polymicrobial Common organism Staphylococcus aureus Escherichia coli Streptococcus pyogenes Proteus mirabilis Pseudomonas aeruginosa Staphylococcus epidermidis ( in the presence of implant)

14. AETIOLOGY Susceptibility/predisposition Local factors Trauma Old scar Poor circulation Chronic bone or joint diseases Presence of foreign bodies Systemic factors Malnutrition Co-morbidities Steroid/ immunosuppression Very young and very old

15. PATHOGENESIS Route of infection Haematogenous Suppurative infections e.g. abscess, boil, OM Endocarditis URTI UTI Drug addicts Direct contamination Trauma Penetrating wounds Contamination of compound fracture Surgery

16. PATHOGENESIS Route of infection Direct spread from contiguous focus of infection Dental abscess Acute purulent frontal sinusitis Deep pressure sore Infection usually starts in the vascular metaphysis of a long bone Epiphyseal involvement can occur in children <2years

17. PATHOGENESIS Source of Infection Metaphysis Bacterial colonization Blood stream Venous stasis

18. PATHOLOGY The pathological picture depends on; the patient’s age, the site of infection, the virulence of the organism and the host response However, the classical picture is seen in children 2-6years of age I nvolves growing bone P articularly the metaphyses of the long bone (distal femur, proximal tibia, distal humerus , distal radius)

19. PATHOLOGY In infants, infection frequently spreads to the epiphysis and from there to the adjacent joint Acute osteomyelitis in adults usually follows an open injury, an operation or spread from a contiguous focus of infection True haematogenous osteomyelitis is uncommon in adults and when occurs usually affect one of the vertebrae

20. PATHOLOGY The pathologic process involves Inflammation Suppuration Necrosis New bone formation Resolution/ Chronicity

21. PATHOLOGY Inflammation The earliest change in the metaphysis First 24 hours Vascular congestion Polymorphonuclear leukocyte infiltration Exudation 2-3 day if not treated with antibiotic  Intraosseus pressure  intense pain  intravascular thrombosis  ischemia

22. PATHOLOGY Suppuration 4-5 days Pus formation Pus spreads via Volkmann canals Children – subperiosteal abscess, Epiphysis, joint Adult- medullary cavity soft tissue In vertebrae it spreads via end plates and disc to adjacent vertebral bodies

23. Spread of pus in haematogenous osteomyelitis

24. PATHOLOGY Necrosis Bone death by the end of a week Bone destruction Toxin I schemia Epiphyseal plate injury Sequestrum formation small  removed by macrophage, osteoclast large  remained

25. PATHOLOGY New bone formation By the end of 2 nd week (10 – 14 days) Involucrum (new bone formation from deep layer of periosteum ) surround infected tissue. If infection persist- pus discharge through sinus to skin surface Chronic osteomyelitis

26. PATHOLOGY Resolution Pathologic process is halted Infection controlled early Intraosseous pressure released Increased bone density Normal anatomy may be reconstituted or bone is left permanently deformed

27. PATHOLOGY Chronicity The hallmark- infected dead bone within a compromised soft tissue envelope Dead or devitalized bone- sequestrum - is surrounded by a cavity containing pus Pathology in COM include Sequestrum formation Involucrum Cloaca Multiple sinuses Soft tissue fibrosis

28. PATHOLOGY Chronicity The chronicity is favoured by formation of a biofilm Formation of conditioning film Bacterial adhesion Bacterial aggregation Biofilm maturation/mutation Detachment/dispersion

29. MANAGEMENT OF ACUTE OSTEOMYELITIS History Presentation is influenced by the age of the patient Infants High index of suspicion Birth difficulties Umbilical artery catheterization site of infection Refusal of feeds Failure to thrive Fever

30. MANAGEMENT OF ACUTE OSTEOMYELITIS History Children Pain in the affected limb Fever Swelling Malaise Refusal to use the limb Not allowing the limb to be touched History of septic focus Infection of toe Ear discharge Sore throat Boil

31. MANAGEMENT OF ACUTE OSTEOMYELITIS History Adults Pain Fever Malaise Swelling History of prior surgical intervention

32. MANAGEMENT OF ACUTE OSTEOMYELITIS Physical examination General signs Toxic Dehydration Palor Pyrexia Tachycardia Features of shock Systemic features may be mild in very elderly and immunocompromised

33. MANAGEMENT OF ACUTE OSTEOMYELITIS Physical examination Local signs Limb held still Tenderness Restricted joint movement Swelling Multiple sites Lymphadenopathy Local signs- late signs

34. MANAGEMENT OF ACUTE OSTEOMYELITIS Investigations Radiological Plain x-ray Features usually manifest after 2 weeks Feature of soft tissue swelling Patchy rarefaction of the metaphysis Faint extra cortical outline- new bone formation Periosteal thickening Combination of regional osteoporosis with a localized area of reduced density

35. Radiographic features of acute osteomyelitis

36. MANAGEMENT OF ACUTE OSTEOMYELITIS Investigations Radiological Uss Detection of subcutaneous/ subperiosteal fluid collection Raddionuclide scanning Detects signs of inflammation as early as 24-48hrs Highly sensitive but has relatively low specificity

37. MANAGEMENT OF ACUTE OSTEOMYELITIS Investigations Radiological MRI Involvement of axial skeleton Bone marrow inflammation Differentiate between soft tissue infection and osteomyelitis Extremely sensitive but low specificity

38. MANAGEMENT OF ACUTE OSTEOMYELITIS Investigations Laboratory Blood culture 3 different samples 2hrs apart or at the height of fever Culture and sensitivity of available aspirate FBC + diff C- reactive protein ESR

39. MANAGEMENT OF ACUTE OSTEOMYELITIS Differential diagnosis Cellulitis Septic arthritis Pyomyositis Rheumatic fever Sickle cell bone crisis Malignant tumour

40. MANAGEMENT OF ACUTE OSTEOMYELITIS Treatment Acute osteomyelitis is an orthopaedic emergency Principles of treatment Supportive treatment Splintage Antibiotic therapy Surgical drainage

41. MANAGEMENT OF ACUTE OSTEOMYELITIS Treatment Supportive treatment Analgesics Antipyretics Rehydration Correction of anaemia if present Nutritional support

42. MANAGEMENT OF ACUTE OSTEOMYELITIS Treatment Splintage of the affected limb For comfort Prevents joint stiffness Reduces risk of pathological fracture Can be done through; Cast splintage Continuous traction

43. MANAGEMENT OF ACUTE OSTEOMYELITIS Treatment Antibiotic therapy Principles Appropriate drug Appropriate dosage Appropriate route Appropriate time to stop Appropriate adjunctive measures Preferably investigation samples should be taken before commencing antibiotic Empirical therapy is started pending results of culture and sensitivity I/V antibiotics is given until patient is clinically better (usually about 2 weeks) then oral for further 4 weeks

44. MANAGEMENT OF ACUTE OSTEOMYELITIS Treatment Antibiotic therapy Neonates and infants Flucloxacillin + 3 rd generation cephalosporin, or Flucloxacillin + benzypenicillin + gentamicin Children and adults Flucloxacillin + fusidic acid or benzylpenicillin 3 rd generation cephalosporin can be used in cases of allergy to penicillin Elderly Flucloxacillin + 2 nd or 3 rd generation cephalosporin

45. MANAGEMENT OF ACUTE OSTEOMYELITIS Treatment Antibiotic therapy Sickle cell disease patients Fluoroquinolones or 3 rd generation cephalosporin IV drug users and immunocompromised Fluoroquinolones or 3 rd generation cephalosporin

46. MANAGEMENT OF ACUTE OSTEOMYELITIS Treatment Surgical intervention Indication Abscess formation Failure to respond to IV antibiotics after 48hrs Debridement of infected tissues Aim of surgery Drain abscess cavity Remove all non viable/necrotic tissues

47. MANAGEMENT OF ACUTE OSTEOMYELITIS Treatment Surgical intervention Methods Open drainage Drilling Opening small bone window Post operative Splintage of the affected limb Post op antibiotics Follow up for at least one year

48. MANAGEMENT OF ACUTE OSTEOMYELITIS Treatment Inflammatory phase Antibiotics Suppurative phase Core decompression Bone destruction phase Debridement ± incision and drainage

49. COMPLICATIONS OF ACUTE OSTEOMYELITIS Septic arthritis Septicaemia Pathologic fracture Chronic osteomyelitis

50. MANAGEMENT OF CHRONIC OSTEOMYELITIS History May arise as a result of inappropriately treated acute osteomyelitis Following trauma Characterized by recurrent episodes of acute exacerbations Presentation Pain (recurrent) Sinus discharge – continuous or recurrent Swelling of the affected limb with or without deformity

51. MANAGEMENT OF CHRONIC OSTEOMYELITIS Physical examination Multiple discharging sinuses Hyper-pigmentation of surrounding skin Skin excoriation may be present Puckering and adherence of soft tissue to the underlying bone Bone deformity or non union in post traumatic Limb shortening if growing epiphysis is affected

52. Chronic osteomyelitis in a child

53. Chronic osteomyelitis in an adult

54. Osteomyelitis following fracture

55. MANAGEMENT OF CHRONIC OSTEOMYELITIS Investigations Radiological Plain x-ray Sequestra - indicating areas of necrotic bone surrounded by a dense involucrum A sizeable length of the diaphysis may be devitalized and encased in a thick involucrum There may be pathological fracture A sinogram may help to localize the site of infection CT and MRI Useful in planning operative treatment: Will show the extent of bone destruction reactive oedema hidden abscesses and sequestra

56. Radiographic features of chronic osteomyelitis

57. Radiographic features of chronic osteomyelitis

58. A sinogram

59. MANAGEMENT OF CHRONIC OSTEOMYELITIS Investigations Laboratory Culture and sensitivity of specimen from discharging sinus FBC + diff C- reactive protein ESR may be high during acute flares Biopsy specimen for histology and microbiological studies

60. CLASSIFICATION OF COM Cierny and Mader Staging System for Chronic Osteomyelitis

61. Anatomic classification of COM

62. CLASSIFICATION OF COM Cierny and Mader Staging System for Chronic

63. MANAGEMENT OF CHRONIC OSTEOMYELITIS Treatment Difficult to eradicate completely Multifaceted approach Goal- Eradication of the infection by achieving a viable and vascular environment Principles Antibiotic therapy Treatment of co morbidities Surgical debridement Dead space management Soft tissue care

64. MANAGEMENT OF CHRONIC OSTEOMYELITIS Treatment Antibiotic therapy To suppress the infection and prevent its spread to healthy bone To control acute flares Choice- microbiological studies Must be able to penetrate sclerotic bone Should be non toxic with long term use

65. MANAGEMENT OF CHRONIC OSTEOMYELITIS Treatment Antibiotic therapy Common antibiotics Clindamycin Fusidic acid Cephalosporins Fluoroquinolones Rifampicin Vancomycin in MRSA Administered for 4-6 weeks before considering surgical intervention

66. MANAGEMENT OF CHRONIC OSTEOMYELITIS Treatment Treatment of co morbidities Optimization of blood sugar in diabetic patients Cessation of smoking Treatment of liver or renal malfunction Nutritional rehabilitation Correction of anaemia

67. MANAGEMENT OF CHRONIC OSTEOMYELITIS Treatment Surgical debridement A waiting policy/period Indication Intractable wound Failure of antibiotic treatment Clear evidence of sequestrum Infected and/or non united fracture Presence of foreign implant

68. MANAGEMENT OF CHRONIC OSTEOMYELITIS Treatment Surgical debridement Surgery is done when Acute flare has subsided Living bone can be distinguished from dead bone Mature Involucrum All the sinus tracts are injected with methylene blue 24 hours before surgery Sinus tracts are excised and laid open up to the cloaca Involves sequestrectomy and resection of scared and infected soft tissues

69. MANAGEMENT OF CHRONIC OSTEOMYELITIS Treatment Management of dead space Antibiotics impregnated beads 2 staged procedure 1 staged procedure Papineau technique Radical excision of all the infected tissue Cancellous autogenous bone grafting mixed with antibiotics and fibrin sealant Wound coverage by skin grafting and other techniques Archdeacon and Messerschmitt modification of the Papineau technique

70. MANAGEMENT OF CHRONIC OSTEOMYELITIS Treatment Management of dead space Closed suction drains- Lautenbach technique Radical debridement Closed irrigation and suction drainage with antibiotic solution Local muscle flap and skin grafting Microvascular transfer of muscle, myocutaneous , osseous, and osteocutaneous flaps The use of bone transport ( Ilizarov technique)

71. Lautenbach drainage system

72. MANAGEMENT OF CHRONIC OSTEOMYELITIS Treatment Soft tissue cover Small defects- split thickness skin grafts larger wounds -local musculocutaneous flaps, or free vascularized flaps

73. MANAGEMENT OF CHRONIC OSTEOMYELITIS Treatment Adjunctive therapy Hyperbaric oxygen Use of growth factors Bone morphogenic proteins (BMP) Plasma rich peoteins (PRP) Physical energy modalities Pulsed electromagnetic field (PEMF) Ultrasound

74. COMPLICATION OF CHRONIC OSTEOMYELITIS Pathologic fracture Acute exacerbation of chronic disease Deformity Growth disturbance Amyloidosis Epithelioma /malignant transformation

75. PECULIARITIES Poor socio-economic conditions Late presentation

76. CONCLUSIONS The key to successful management is early diagnosis, appropriate antimicrobial and surgical treatment A multi disciplinary approach is required, involving an orthopaedic surgeon, an infectious disease specialist, and a plastic surgeon in complex cases with significant soft tissue loss

77. REFERENCES Louis Solomon et al; Infections, in Apley’s System of Orthopaedics and Fractures, 9 th ed. 2010; 2: 29-41 John Ebenezer; Osteomyelitis, in Textbook of Orthopaedics, 5 th ed. 2010; 38:540-550 O. Popoola ; Acute and chronic infections of bone and joints, in Principles and Practice of Surgery in the Tropics including Pathology, 5 th ed. 2015; 54:1136-1140

78. REFERENCES Gregory D. Dabov ; Osteomyelitis, in Campbell’s operative orthopaedics, 12 th ed. Vol. I, 2013; 21:725-747 S. C. Goel ; Pyogenic haematogenous osteomyelitis, in Textbook of orthopaedics and trauma, 2 nd ed. Vol. I, 2008; 27:249-267 Martin McNally et al; infections of the bone and joints, in Bailey and Love’s Short Practice of Surgery, 26 th ed. 2013; 40: 541-549