Orthopedics Lec 5 PDF

Osteomyelitis&septic arthritis By Hany Hamed Prof. of Orthopaedic surgery Osteomyelitis Nelaton (1834) : coined osteomyelitis The root words osteon (bone) and myelo (marrow) are combined with itis (inflammation) to define the clinical state in which bone is infected...

Osteomyelitis&septic arthritis By Hany Hamed Prof. of Orthopaedic surgery Osteomyelitis Nelaton (1834) : coined osteomyelitis The root words osteon (bone) and myelo (marrow) are combined with itis (inflammation) to define the clinical state in which bone is infected with microorganisms. introduction Osteomyelitis is an inflammation of bone caused by an infecting organism. It may remain localized, or it may spread through the bone to involve the marrow, cortex, periosteum, and soft tissue surrounding the bone. classification Attemps to classify are based on 1-duration and types of symptoms 2- the mechanism of infection 3-the type of host response (pyogenic or non) Classified according to mechanism Osteomyelitis may be  1.Exogenous -direct (trauma, surgery (iatrogenic) (mixed bacteria ) -contiguous infection)  2. Hematogenous (bacteremia) Usually monomicrobial Organism Comments Staphylococcus aureus Commonest in all types of osteomyelitis Coagulase negative staphylococci or Foreign-body associated infection Propionibacterium Pseudomonas IV drug users and Nosocomial infection Bite injuries, Diabetic foot lesion, Decubitus Streptococci or Anaerobic ulcer Salmonella Sickle cell disease Bartonella henslae HIV Pasturella or Eikenella Human or animal bites Fungal Immunocompromised patients Mycobacterium tuberculosis TB endemic regions Group B streptococci 2-4 weeks age (neonates) H. influenzae 6 months to 4 years age Risk factors recent trauma or surgery immunocompromised patients IV drug use poor vascular supply systemic conditions such as diabetes and sickle cell peripheral neuropathy Acute Hematogenous osteomyelitis  Most common type of bone infection, usually seen in children < 15 years of age although adults can have this disease  More common in males  occurs in the metaphysis of the long bones. why metaphysis is involved Relative lack of phagocytosis activity in metaphyseal region Frequent trauma Highly vascularised region ---minor trauma-hemorrhage ---- excellent culture medium  Diaphysial osteomyelitis : Earlier metaphysis but due to growth becomes diaphyseal mostly in children. Direct trauma to diaphysis Tubercular Pathogenesis  Whatever may be the cause the bacteria reaches the metaphysis of rapidly growing bone & provokes an inflammatory response which can cause local ischaemic necrosis of bone and subsequent abscess formation..  As the abscess enlarges, intramedullary pressure increases causing cortical ischaemia, which may allow purulent material to escape through the cortex into the subperoisteal space.  A subperisoteal abscess then develops  If left untreated this process eventually results in extensive sequetra formation and chronic osteomyelitis  In children younger than 2 years, blood vessels cross the physis, thus epiphysis may be involved.  Limb shortening or angular deformity may occur  In children older than 2 years the physis effectively acts as a barrier to the spread of a metaphyseal abscess Clinical picture History Duration trauma prior treatments characterize host immunocompromised Symptoms pain swelling Fever Inability to move the limb Physical exam vital signs fever, tachycardia, and hypotension suggest sepsis Inspection&palpation erythema, tenderness,swelling and edema are commonly seen draining sinus tract motion limp and/or pain inhibition with weight-bearing or motion may be present Pseudo paralysis assess the joints above and below the area of concern neurovascular assessment of vascular insufficiency locally or systemically Laboratory findings  The white blood cell count will show a marked leucocytosis as high as 20,000 or more  Increase ESR  Increase CRP suspected abscess  Aspiration of pus. The point of maximal tenderness should be aspirated with a large-bore needle. X-ray findings  X-ray films are negative within 1-2 weeks - Careful comparison with the opposite side may show abnormal soft tissue shadows. - It must be stressed that x-ray appearances are normal in the acute phase. There are little value in making the early diagnosis.  Localized osteopaenia  trabecular destruction are early signs of a suppurative acute process in the bone(lytic lesion)  Lamellated periosteal reactions are invariably present Sonography  Ultrasound cannot directly access bone marrow abnormalities present in osteomyelitis but can document osteomyelitis indirectly by identifying periosseous soft tissue abnormalities  The very first sonographic sign, seen even before any periosteal reaction, is edematous swelling of the deep soft tissues Bone scan  Radioisotopic bone scanning is valuable in early localization (within 48 hrs) of bone infection.  Technitium-99m imaging is very sensitive, it is the choice for acute hematogenous osteomyelitis, the overall accuracy being 92%. CT : late erosion of cortex Magnetic Resonance Imaging:  Magnetic resonance imaging has very high sensitivity and specificity. * Advantage: Useful for differentiating between bone and soft-tissue infection. Helpful in surgical planning. Differential diagnosis  TB  Soft tissue infection  Ewing sarcoma  Osteoid osteoma  Esonphilic granuloma Treatment  1.General treatment: nutritional therapy or general supportive treatment by intaking enough caloric, protein, vitamin etc.  2. Antibiotic therapy  3. Surgical treatment  4. Immobilization Nade's principles of antibiotic  Antibiotic is effective before pus forms  Antibiotic cannot sterilise avacular tissue  Antibiotic prevents reformation of pus once removed  Pus removal restores periosteum---- restores blood flow  Antibiotic should be continued after surgery Nade's indications for surgery  1. Abscess formation  2. Severely ill child with features of acute osteomyelitis  3. Failure to respond to IV antibiotics for >48 hrs The objective of surgery is to drain any abscess cavity and remove all non viable or necrotic tissue Complications  Chronic osteomyelitis-  Septic arthritis  Growth disturbance  Septicemia  DVT  Pulmonary embolism SUBACUTE HEMATOGENOUS OSTEOMYELITIS  More insidious onset and lacks the severity of symptoms  Diagnosis typically is delayed for more than 2 weeks.  a pathogen is identified only 60% of the time  S. aureus and Staphylococcus epidermidis  The diagnosis often must be established by an open biopsy and culture Brodie's abcess  Localized Subacute osteomyelitis  Age 11-20 yrs,  metaphyseal area, usually upper tibia or lower femur  intermittent Deep boring pain, worse at night, relieved by rest  Circular or oval luscency surrounded by zone of sclerosis  Bone abscess containing pus or jelly like granulation tissue surrounded by a zone of sclerosis  Treatment: Conservative if no doubt - rest + antibiotic for 6 wks. if no response surgical evacuation & curettage, if large cavity - packed with cancellous bone graft  Chronic Osteomyelitis  Chronic osteomyelitis represents a progressive inflammatory process caused by pathogens, resulting in bone destruction and sequestrum formation.  The ‘gold standard’ for the diagnosis of chronic osteomyelitis infected dead bone within a compromised soft tissue envelope  The infected foci within the bone are surrounded by sclerotic, relatively avascular bone covered by a thickened periosteum and scarred muscle and subcutaneous tissue  Clinical features.  During the period of inactivity, no symptoms are present.  Only Skin-thin, dark, scarred, poor nourished, past sinus, an ulceration that is not easily to heal  Muscles-wasting contracture, atrophy  Joint-stiffness  Bone-thick, sclerotic,  During flare up :Locally there will be some heat, swelling, redness, tenderness, edema, because pus may build up in cavity, then a sinus may open and start to exudates purulent materials and small sequestra. Laboratory COM  Erythrocyte sedimentation rate  C reactive protein  WBC count only elevated in 35%  Biopsy for histological and microbiological evaluation Staphyloccocus species Anaerobes and gram negative bacilli Imaging studies in COM Plain X rays Cortical destruction {cloace} Periosteal reaction {involucrum} Sequestra Sinography COM Imaging  CT Scan Identifying sequestra Definition of cortical bone and surrounding soft tissues COM Imaging  MRI  Shows margins of bone and soft tissue oedema  Rim sign- well defined rim of high signal intensity surrounding the focus of active disease Treatment of COM  Surgical treatment mainstay Sequestrectomy Resection of scarred and infected bone and soft tissue Radical debridement Resection margins >5mm Bone Debridement:  Debridement of bone is done until punctate bleeding is noted.  Copious irrigation with 10 to 14 L of normal saline.  Pulsatile lavage using fluid pressures 50-70 pounds per square inch and 800 pulses per min.  Repeated debridements may be required. Post sequestrectomy.  NO STABLISATION IS NECESSARY WHEN more than 70% OF THE ORIGINAL CORTEX REMAINS INTACT.  If 70% cortical volume has been retained-protect by cast.  Focal bone loss-open cancellous BG/conventional BG.  Greater bone loss-Ext fix.  Seg. bone loss-BG/Bone transport/other devices. Treatment of COM  Antibiotic duration is controversial 6 week is the traditional duration 1 week IV, 6 weeks of oral therapy  Antibioticpolymethyl methacrylate (PMMA) beads as a temporary filler of dead space  Biodegradable antibiotic delivery system Complications:-  Acute exacerbations- most common.  Growth abnormalities.  Deformities.  Pathological #.  Jt. Stiffness.  Amylodosis.  Malignancy(0.25%) -sq. cell carcinoma most common, reticulam cell carcinoma,fibrosarcoma.  Septic arthritis- hip, ankle, shoulder ,elbow.  Garre' s osteomyelitis.  Sclerosing, nonsuppurative.  No abcess, cortical thickening.  Acute local pain, pyrexia subside- fusiform swelling.  Acute stage-rest, antibiotics.  Surgical ttt: Gutter ,excision+curettage.  Septic arthritis  Definition: Septic arthritis is an inflammation of synovial membrane with purulent effusion into the joint capsule due to infection by organism. Also referred as infectious arthritis Considered as medical emergency It can cause septic shock, which can be fatal. All age groups, infants and older adults are most likely to develop septic arthritis. 50% >age 3 M=F The knee is the most commonly affected but any joint may be involved.  Risk factors Contiguous spread Skin infection, cutaneous ulcers Direct inoculation Previous intraarticular injection Prosthetic joint: early and delayed Recent joint surgery Hematogenous spread Diabetes mellitus immunodeficiency virus infection¹¹ Immunosuppressive medication Intravenous drug abuse! Osteoarthritis Other cause of sepsis Prosthetic joint: late Rheumatoid arthritis Sexual activity Other factors Age older than 80 years Etiology (microbiology)  Microbial agent:  Staphylococcus aureus: most common (75-80%)  Other organism in special patients:  Elderly,IV drug abuser, immunocompromised, UTI: Gram negative (p. aeruginosa and E.coli) SYNOVIUM Cartilage SYNOVIAL FLUID Cartilage Pathology  There is an acute synovitis with a purulent joint effusion and Synovial membrane becomes edematous, swollen and hyperemic, and produces increase amount of cloudy exudates contains leukocytes and bacteria  As infection spread through the joint, articular cartilage is destroyed by bacterial and cellular enzymes.  If the infection is not arrested the cartilage may be completely destroyed.  Pus may burst out of the joint to form abscesses and sinuses.  The joint may be become pathologically dislocated. Clinical manifestations  Fever (toxic)  Acute Sever pain  Sever swelling of one joint  Sever tenderness  Warmth  Sever effusion  Sever limited ROM Physical examination 1. Decreased or absent rang of motion. 2. Signs of inflammation: joint swelling, warmth, tenderness and erythema. 3. Joint orientation as to minimize pain (position of comfort): Hip: abducted, flexed and externally rotated. Knee, ankle and elbow: partially flexed. Shoulder: abducted and internally rotated Investigation Lab. INVESTIGATIONS 1-Blood investigation Raised WCC Raised ESR and CRP Blood culture (positive) 2- SYNOVIAL FLUID ANALYSIS Turbid - Purulent Leukocyte> 50,000/ml (> 90% PMN) Damaged WBC Crystal (-) Aspiration of pus (sure lab diagnosis) IMAGING X-ray Early stage: May look normal except widening of joint space Late stage: Narrowing and irregularity of joint space; may have OM changes of adjacent bones Ultrasonography This study is very sensitive in detecting joint effusions generated by septic arthritis. MRI and radionuclide imaging are helpful in diagnosing arthritis in obscure sites such as the sacroiliac and sterno-clavicular Kocher Criteria for Septic Arthritis of the Hip Temperature >101.3°F (38.5°C) White blood cell count>12,000/μL (12x109/L) Erythrocyte sedimentation rate >40 mm/h Inability to ambulate "C-reactive protein >2.5 mg/L (23.81 nmol/L) DIFFERENTIAL DIAGNOSIS 1. Acute osteomyelitis 2. Trauma 3. Hemophilic bleed 4. Rheumatic fever 5. Juvenile rheumatoid arthritis 6. Sickle-cell disease 7. Gaucher's disease 8. Gout and pseudo-gout  treatment 1st priority-aspirate the joint and examine the fluid. General supportive care - analgesics and IV fluid Splintage Antibiotics a. Neonates and infants up to 6 months - penicillin (flucloxacillin) + 3rd gen cephalosporin b. Children from 6 months to puberty - similar to above. c. Older teenager and adults - flucloxacillin and fusidic acid and 3rd generation cephalosporin Surgical -needle aspiration -arthrotomy(open or arthroscop) COMPLICATIONS 1. Bone destruction and dislocation of the joint (especially hip) 2. Cartilage destruction 3. May lead to either fibrosis or bony ankylosis 4. In adult partial destruction of the joint will result in secondary osteoarthritis 5. Growth disturbance Presenting as either localized deformity or shortening of the bone