1 Infection in Bone and JointPresented By: Fadel Naim M.D. Orthopedic Surgeon IUG

2 Osteomyelitis osteon (bone) myelo (marrow) itis (inflammation)Inflammation and destruction of bone caused by aerobic and anaerobic bacteria, mycobacteria, and fungi The term osteomyelitis does not specify the causative organism or the disease process

3 Epidemiology Common in young childrenCommon with malnutrition, immunodeficiency - with decreased resistance of the patient Boys> girls History of trauma Decreasing in incidence & severity & mortality with advent of newer antibiotics

4 Osteomyelitis Classification: Duration Acute, Subacute or ChronicRoute of infection Hematogenous or Exogenous Host response Pyogenic or Granulomatous

5 Acute Pyogenic Osteomyelitisinfants Staphylococcus aureus, Streptococcus agalactiae, Escherichia coli children over one year Staphylococcus aureus, Streptococcus pyogenes, and Haemophilus influenzae adults Staphylococcus aureus

6 Source Of Infection Hematogenous spread Direct inoculationContiguous focus of infection

7 The most common site is the rapidly growing and highly vascular metaphysis of growing bonesThe apparent slowing or sludging of blood flow as the vessels make sharp angles at the distal metaphysis predisposes the vessels to thrombosis the bone itself to localized necrosis and bacterial seeding

8 The joint is usually spared from infection unless the metaphysis is intracapsular, as is found in the proximal part of: The radius The humerus The femur

9 Age variation Neonates: Extensive bone necrosisIncreased ability to absorb large sequestrum Increased ability to remodel Epiphysio-metaphyseal vascular connection leading to secondary septic arthritis

10 Age variation Adults: No subperiosteal abscess due to adherent periosteum Soft tissue abscess Vascular connection with the joint leading to secondary septic arthritis

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13 Acute Osteomyelitis DiagnosisHistory and clinical examination CBC, ESR, B.C. X-ray (normal in the first (10-14) days Ultrasound Bone Scan Tc 99, Gallium 67 MRI Aspiration

14 Radiographic FindingsUsually reflect the destructive process but lag at least two weeks behind the process of infection The earliest changes are: Swelling of the soft tissue Periosteal thickening and/or elevation Focal osteopenia At least 50% to 75% of the bone matrix must be destroyed before radiographs show lytic changes

15 (A) Proximal humerus at day 1 of infection - no visible changes.(B) Proximal humerus at day 12 of infection

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19 Plain-film radiograph showing osteomyelitis of the second metacarpal (arrow).Periosteal elevation, cortical disruption and medullary involvement are present.

20 The above X-ray of the left ankle of a 10-year-old boy shows lucency in the tibial metaphysis secondary to acute hematogenous osteomyelitis (AHO). The above X-ray of the right ankle of a 10-year-old boy shows lucency in the tibial metaphysis secondary to acute hematogenous osteomyelitis (AHO).

21 Here is an X-ray of an AHO lesion extending into the growth plate

22 Show increase activity but it is a non specific sign of inflamation.Radiological studies MRI : Early detection and surgical localization of osteomyelitis. Sensitivity ranges from %. Radionuclide bone scanning : A 3-phase bone scan with technetium 99m is probably the initial imaging modality of choice Show increase activity but it is a non specific sign of inflamation.

23 This MRI sagittal section shows the same AHO lesions with the right lesion extending into the growth plate.

24 Bone scans, both anterior (A) and lateral (B), showing the accumulation of radioactive tracer at the right ankle (arrow). This focal accumulation is characteristic of osteomyelitis.

25 Labratory The leukocyte count (WBC), erythrocyte sedimentation rate (ESR), and C-reactive protein level (CRP) should be monitored At the time of admission During treatment During follow-up In all patients with osteomyelitis on a weekly basis

26 Diagnosis requires 2 of the 4 following criteria:Purulent material on aspiration of affected bone Positive findings of bone tissue or blood culture Localized classic physical findings of bony tenderness, with overlying soft-tissue erythema or edema Positive radiological imaging study

27 Differential DiagnosisAcute Septic Arthritis Acute monoarticular rheumatoid arthritis Sickle cell crisis Cellulitis Ewing’s Sarcoma

28 Complications Septicemia & metastatic abscesses Septic arthritisGrowth disturbance (children) Pathological fracture Chronic osteomyelitis

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30 Subacute Osteomyelitis

31 Subacute OsteomyelitisResults from a less virulent Microorganism, or a patient with an elevated resistance. Occurs Mostly at the Distal Femur or Proximal Tibia On X-Ray: Brodie’s Abcess Small and Oval in shape It is surrounded by sclerotic bone May be mistaken for Ostieoid Osteoma

32 Subacute OsteomyelitisAn image depicting subacute osteomyelitis

33 Chronic OsteomyelitisThe coexistence of infected, nonviable tissues and an ineffective host response leads to the chronicity of the disease

34 Chronic OsteomyelitisFactors responsible for chronicity Local factors: Cavity, Sequestrum, Sinus, Foreign body, Degree of bone necrosis General: Nutritional status of the involved tissues, vascular disease, DM, low immunity Organism: Virulence Treatment: Appropriateness and compliance Risk factors: Penetrating trauma, prosthesis, Animal bite

35 Pathologic features of chronic osteomyelitis Sequestrum:When both the medullary and the periosteal blood supplies are compromised, large areas of dead bone (sequestra) may be formed Involucrum: New bone forms from the surviving fragments of periosteum and endosteum in the region of the infection to form an encasing sheath of live bone sinus tract: A bone cavity may persist or the space may be filled with fibrous tissue, which may connect with the skin surface by the sinus tract

37 Chronic OsteomyelitisTypes A complication of acute Osteomyelitis Post traumatic Post operative

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39 Chronic OsteomyelitisLow grade fever, if present ESR usually elevated, reflecting chronic inflammation The blood leukocyte count ( WBC ) is usually normal If a sinus tract becomes obstructed, the patient may present with a localized abscess and/or an acute soft-tissue infection

40 Chronic Osteomyelitis OrganismUsually mixed infection Mostly staph. Aureus E. Coli . strep pyogen, proteus

41 Treatment of OsteomyelitisA close interaction between various specialists is important to improve the management of this disease Orthopaedic surgeons Plastic and vascular surgeons Infectious disease specialists

42 Treatment of OsteomyelitisAdequate drainage Thorough débridement Obliteration of dead space Wound protection Specific antimicrobial coverage Correcttion of host defects Improving the nutritional, medical, and vascular status of the patient Good nutrition Smoking cessation Control of specific diseases such as diabetes

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44 Bone Stabilization If skeletal instability is present measures must be taken to achieve stability with plates, screws, rods, and/or an external fixator. External fixation is preferred over internal fixation. Ilizarov external fixation: allows reconstruction of segmental defects and difficult infected nonunion. An extended period of treatment with the device, averaging 8.5 months. The sites of the wires or pins usually become infected and the device is painful.

45 Soft-tissue Coverage Adequate soft-tissue coverage of the bone is necessary to arrest osteomyelitis Small soft-tissue defects may be covered with a split-thickness skin graft For large soft-tissue defects or an inadequate soft-tissue envelope, local muscle flaps and free vascularized muscle flaps may be placed in one or two stages Healing by so-called secondary intention should be discouraged

46 Septic Arthritis

47 Septic Arthritis Septic arthritis : Reactive arthritis:Direct invasion of joint space by a variety of microorganisms, including a variety of bacteria, viruses, mycobacteria, and fungi. Reactive arthritis: A sterile inflammatory process, may be the consequence of an infectious process located somewhere else in the body.

48 Septic Arthritis 50% of cases in children <3 yearsThe hip joint is the common site in <3years, whereas the knee joint is more common in older children.

49 7.8 cases per 100,000 person-yearsThe incidence of gonococcal arthritis is 2.8 cases per 100,000 person-years Septic arthritis is becoming increasingly common among people who are immunosuppressed and elderly people who have a variety of co-morbid diagnoses

50 Most of these infections occur in very young and very old people and among people who abuse intravenous drugs The most commonly involved joint: Knee (50%) Hip (20%) Shoulder (8%) Ankle, and wrists (7% each) Elbow, interphalangeal, sternoclavicular, and sacroiliac joints each make up 1-4% of cases

51 Risk Factors Corticosteroids-33% Existing arthritis-24%Infection elsewhere-22% DM-13% Trauma-12% None-8%

52 Two major classes : Gonococcal Nongonococcal Neisseria gonorrhoeae remains the most frequent pathogen (75% of cases) among younger sexually active individuals Staphylococcus aureus is the most common cause of the vast majority of cases of acute bacterial arthritis in adults and children older than 2 years

53 Organisms may invade the joint by:Direct inoculation Contiguous spread from infected periarticular tissue Bacteremia (the most common route)

54 Acute Septic Arthritis Differential DiagnosisAcute osteomyelitis Trauma Irritable joint Hemophilia Rheumatic fever Gout

55 Diagnosis History Because joint infections are uncommon, be attentive to features of the patient's history that may indicate an infectious process and not a primary rheumatological or orthopedic process

56 Inspection Thorough inspection of all joints for signs of inflammation is essential for diagnosing infection : Erythema Swelling (90% of cases) Warmth Tenderness Limitation of both active and passive ROM

57 Synovial Fluid ExaminationLeukocyte count Appearance on gram stain Polarizing microscopy examination Culture of the fluid Culture of the synovial fluid or of synovial tissue itself is the only definitive method of diagnosing infective arthritis

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61 Imaging Studies Plain radiographs of some limited value in evaluating a joint for infection Radiographs are most useful in ruling out underlying osteomyelitis or periarticular osteomyelitis resulting from the joint infection itself Periarticular soft tissue swelling is the most common finding Ultrasonography may be used to diagnose effusions

62 Acute Septic ArthritisTreatment Aspiration Antibiotics Splintage Surgical drainage Treatment of complications

63 Management of Infective ArthritisManagement of infective arthritis focuses on: Adequate and timely drainage of the infected synovial fluid Administration of appropriate antimicrobial therapy Usually, the antibiotic must be administered parenterally for 3-4 weeks, but each case needs to be evaluated individually Immobilization of the joint to control pain

64 Drainage The choice of the type of drainage, whether percutaneous or surgical, has not been resolved completely Aspirating the joint 2-3 times a day may be necessary during the first few days Surgical drainage is indicated: For the appropriate choice of antibiotics Vigorous percutaneous drainage fails to clear the infection after 5-7 days The infected joints are difficult to aspirate (eg, hip) Adjacent soft tissue is infected

65 Prognosis 50% of adults with septic arthritis have significant sequelae of decreased ROM or chronic pain after infection poor outcome in the following: Age older than 60 years Infection of the hip or shoulder joints Underlying rheumatoid arthritis Positive findings on synovial fluid cultures after 7 days of appropriate therapy Delay of 7 days or more in instituting therapy

66 Thank You