Osteomyelitis

Epidemiology

Classification

More common in neonates (1:1000; children 1:5000); males, sickle cell disease, open fracture, chronic ulcers; peak 6/12 – 4 years, 10-14 years

Acute: <2/52 Subacute: 2-6/52 Chronic: >6/52Knee

Dislocation

Epidemiology: requires much force; can be Anterior: most common, 40%; tibia anterior Posterior: 33% Medial: 4% Lateral: 18% RotatoryUsually med and lat quads remain intact; reduction occurs spontaneously pre- hospital in 65% (but still need to evaluate for vascular injury)

Angiography if: distal pulses, abnormal ABI (if abnormal examination, 40% have a vascular injury)Management: reduction via longitudinal traction splint in 20° flexion and admitComplications: 20-30% are open; single cruciate injury in 85%, both in 70%, med / lat collateral in 40-60%; intra-articular fracture in 25%; popliteal vessel in 35-40% (presence of distal pulses doesn’t exclude injury; ?do arteriogram in all patients; if normal pulse before and after and normal ABI, can just do serial exams); high risk of compartment syndrome (may be delayed after reduction); peroneal nerve injiry in 25-35% ( foot drop, altered sensation lateral foot); 80% risk of amputation if reduction delayed >8hrs

Patella Dislocation

MOI: twisting on extended knee or direct blow; often due to patellofemoral dysplasia, hypoplastic vastis medialis, shallow trochlear groove, genu valgum; 30% have recurrent, 50% ongoing patellofemoral symptomsExamination: 60% have abnormal extensor mechanism, high riding patellar; usually dislocates laterally; patellar apprehension sign (knee flexed at 30°, firm lateral pressure to patella)Complication: torn medial joint capsuleManagement: push medially on patella while extending knee using element of surprise cast or zimmer splint 2-4/52 (minimal immobilisation if recurrent)

Patella Fracture

MOI: direct blow, fall on flexed knee, forceful contraction of quadsTransverse: 80%; more likely to be displaced and associated with disrupted extensor mechanism Examination: loss of SLRManagement: if undisplaced, POP or Zimmer splint 6/52; if >3mm displaced, ORIF

Assessment

Locaslised painInfants – FTT, swelling not prominent, ESR (WBC may be normal), maybe afebrile, rapid spread to epiphysis, may spread to joints, extensive early periosteal reactionsChildren – pain over few hours; 30-50% have history of recent trauma; appear ill, usually febrile, not using limb, usually hip/knee, if hip, internal rotation painfulAdults: usually diabetic, IVDU (especially sternoclavicular and vertebrae), alcoholic, long term steroids

Investigations

XR: ST swelling, poor definition of local fat plains, periosteal new bone formation (in 30% at 7-10/7), radiolucency; joint effusions, joint space widening early, joint space loss late, avascular areas radiodense, surrounding bony resorptionBone scan: 90% sensitivity, poor specificityCT: good for peripheriesMRI: good for spineBloods: ESR/CRP in 90%; blood cultures +ive in 50%; WCC not sensitive

Management

Flucloxacillin 25-50mg/kg QID AND cefotaxime 25-50mg/kg TDS OR ceftriaxone 50mg/kg ODAugmentin if ?Hib4/52 IV if neonate

<5yrs

Flucloxacillin 25-50mg/kg QIDMinimum 3/7 IV; total duration minimum 4/52>5yrs

Flucloxacillin 2g IV QID for 2-4/52 (6/52 if chronic) (+ cefotaxime 2g TDS if ?G-ives)If MRSA: vancomycin rifampicinIf penicillin allergy: cephazolin 4/52 IV; total duration minimum 6/52

Adults

ACL Injury

Lateral condyle of femur anterior intercondylar eminence of tibia (may be associated with avulsion # here = Segond # (see X-ray above))Prevents: anterior movement of tibia on femur; stabilises knee in extensionTest: Lachman (85-95% sensitivity, 100% specificity; >5mm positive) Anterior drawer (60% sensitivity, 65% specificity; >6mm positive) lateral pivot shift (40-70% senstivity) knee arthrometer (95% sensitivity)Epidemiology: most commonly injured ligament; accounts for 70% haemarthroses; associated with MCL/LCL/meniscal injury in 50%MOI: rotational, hyperextension, deceleration snap/popComplication: medial meniscal tearMng: OT

PCL Injury

Medial condyle of femur posterior intercondylar eminence of tibia (may be associated with avulsion fracture here)Prevents: posterior movement of tibia on femur; stabilises knee in flexionTest: Godfrey’s sign posterior drawer (55-85% sensitivity)Epidemiology: rarely isolated; associated with hip injury, femoral and tibial fractureMOI: blow to leg with flexed kneeMng: may be conservative if isolated injury

MCL Injury

Medial epicondyle of femur medial proximal tibia (7cm from joint) (also attached to medial meniscus)Epidemiology: most common isolated ligament injury; may be associated with ACL injuryMOI: abduction, flexion, internal rotation; rupture if >1cm laxity without endpointMng: conservative, unless other ligament involved

LCL InjuryLateral epicondyle of femur lateral fibula? (separated from lat meniscus by popliteus tendon)MOI: adduction, flexion, external rotation; rupture if >1cm laxity without endpointComplication: peroneal nerve injMng: conservative, unless other ligament involved

Meniscal InjuryMedial mensicus 2x more common; most are posterior aspect of meniscusTest: Bragard’s sign (medial) McMurray’s test (50% sensitvitiy) Apley compression / Grind test (50% sensitivity)

Baker’s Cyst Protrusion of synovium and synovial fluid into semimembranous bursa; popliteal fossa ache; palpable bulge; do USS; symptomatic treatment