1. Infections of the Hip in children
Ram Pulavarti

3. Septic arthritis of hip
Thomas Smith cases of acute septic arthritis with mortality >50%
Since the introduction antibiotics,
mortality < 1%
Early treatment
Initial diagnosis must be on clinical basis

4. Importance Common problem ‘Irritable hip’
problems inherent to diagnosis and treatment
Protean manifestations eg., pain, limp, septicemia, mimic tumor
Other conditions such as JRA

5. After diagnosis What antibiotic before culture results are known?
What if cultures are negative?
Route of administration?
How long?
When is surgery indicated?
Diversity of organisms, various possible locations
Numerous conditions associated with bone and joint sepsis

6. Hip Disaster
Risk of dislocation
AVN
Shorter leg
Stiffness

7. Infections of the hip Non specific: bacterial
Specific: TB, fungal, viral
Haematogenous
Post Traumatic
Iatrogenic

8. Epidemiology Septic arthritis twice as common as osteomyelitis
peak incidence in early years of the first decade
Osteomyelitis : peak incidence in the later years of the first decade
M > F
A H O more in early autumn and late summer in both hemispheres (Gillespie, CORR 1973)
Higher incidence New Zealand Maoris, Australian aborginals

9. Osteomyelitis (AHO) A changing disease
A study from Glasgow:
< 13 years of age AHO has dropped by more than 50%
incidence of subacute infections increased from 12-42%
Craigan MA et al JBJS Br 1992; 74:541
Jones NS et al JBJS Br 1987; 69:779

10. Frequency of osteomyelitis and septic arthritis according to age (yrs) McCarthy JJ et al JBJS 2004

11. Sites Knee (41%) Hip 23% Ankle 14% Elbow 12% Shoulder (4%)
(Jackson and Nelson 1982)

12. Septic arthritis Primary seeding of synovium
Secondary to metaphyseal infection eg., hip, shoulder, ankle, elbow
Transepiphyseal vessels (up to 18 months)
Directly from infection of epiphysis

13. Septic arthritis of hip in infancy

14. Pathogenesis of Haematogenous infection
Septic emboli
Trauma, haematoma
Reduced immunity
Glycocalyx (Biofilm)

15. Why metaphysis? Vascular loop theory Immature phagocytosis theory
Injury theory
Injection of bacteria as the hemorrhage is forming leads to infected haematoma
(Morissy and Haynes 1989)

16. Course of metaphyseal abscess
transphyseal vessels  into the joint
Spreading infective thrombosis and periosteal stripping  dead bone
Epiphysis may separate
the hard cortex  sequestrum
infection remains active as long as the sequestrum is present

17. Course of metaphyseal abscess
involucrum formation
Left alone, pus kills the periosteum and no new bone is formed
Rupture of the periosteum: pus tracks through a soft-tissue planes ‘sinus’

18. Metaphyseal abscess

19. Septic arthritis Pathology
a fibrin-rich exudate
Clotted exudate – a cast in the joint
Cartilage destruction: lysozymal enzymes dissolve the glycosaminoglycans of the articular cartilage.
The femoral head + growth plate destruction
Organisms may vary in their ability to dissolve cartilage :
staphylococcus is most damaging
Hemophilus inflenzae and Gonococcus are the least damaging

20. Diagnosis Clinical suspicion Examination : lap exam
temp is often normal
examine everything before trying the joint – because as soon as this touched, all cooperation is gone
Look: is it swollen, warm, can the child move it

21. Temperature Klein et al: Temp below 380C in 31% Del Bacarro et al:
Mean temp 38.10C degrees C
Gandini
Mean temp: 39.20C

22. Kocher criteria (for child with painful hip)
non-weight-bearing on affect side,
Sedimentation rate greater than 40 mm/hr,
fever, and
WBC count of >12,000 mm3;
when 4/4 criteria are met, 99% chance that the child has septic arthritis; when 3/4 criteria are met, 93% chance of septic arthritis; when 2/4 criteria are met, 40% chance of septic arthritis; when 1/4 criteria are met, 3% chance of septic arthritis;          
Ref: Kocher et al JBJS 2004,

23. Organisms Newborn Staphylococcus 36% Streptococcus (21%) E.coli 14%
1month to 5 yrs:
hemophilus inflenzae (31%)
Children over 5 years: staphylococcus
Sexually active teenager - Gonococcus

24. Negative cultures Because many patients with
septic arthritis have negative cultures,
it is important to use criteria
that include those patients

25. Diagnosis CBC ESR: most sensitive test; 90% elevated to medium levels
CRP
Blood cultures
Sickle-cell test for black children
X ray: to rule out preexisting lesions;
Bone Scan: useless at distinguishing septic from nonseptic joints
Ultrasound
Definitive test: needle aspiration of a septic joint

26. Laboratory Leukocyte count – not reliable in early stages
Only 25% of infants and children with osteomyelitis have a leukocyte count above normal for their age
Only 65% of infants and children with osteomyelitis had the differential count abnormal

27. Most useful lab test in bone and joint sepsis:
Laboratory
Most useful lab test in bone and joint sepsis:
CRP
ESR

28. Laboratory data
Normal ESR, CRP or WCC does not exclude the presence of infection
Average ESR between 37-94mm/hr
Del Becarro et al.
ESR 44 in septic arth :: 19 trans synovitis
Klein et al average ESR 51mm/h, 95% had an ESR >20mm
Gandini 2003:
ESR 65mm/hr; all children >20mm/hr
CRP mean CRP 144mg/L, all > 20mg/L

29. ESR
non specific
unreliable in a neonate, anaemia, sickle cell disease, on steroids
almost always elevated 48-72hrs of onset of infection
returns to normal over 2-4 weeks after elimination of the infection
less reliable in the first 48hrs than after 48hrs
continues to rise for 3-5 days after institution of successful therapy
therefore not a good means of response to treatment in the first week

30. CRP inflammation or trauma
May rise within 6hrs then increases several hundred fold
peak within 36-50hrs
Falls quickly to normal with successful treatment
early diagnosis and resolution of inflammation

31. Aspirate rinse with heparin before aspirate
Gram stain : organisms in about one third of bone and joint aspirates

32. Cultures Blood culture: 30-50% yield
The yield from cultures decreases with previous antibiotic therapy

33. Microbiology Gandini: 27% joint fluid positive culture
72% blood cultures
no Haemophilus influenza cases
Bennet and Namnyak
joint fluid positive culture in 91%
Blood culture: 42.5%

34. No string in turbid fluid of septic joints
hyaluronate is broken down by enzymes

35. Differential diagnosis
The Hip – leukemia, pelvic osteomyelitis, transient synovitis, discitis, appendicitis
Rheumatoid arthritis hardly ever, begins in the hip

36. Organisms causing AHO Age group Organism Antibiotic Neonates
Group B streptococcus, Sta. aureus, gram-negative rods
Cefotaxime or Oxacillin and gentamicin
Infants and children
Sta. aureus (90%)
Oxacillin
Pts with sickle cell disease
Staphylococcus aureus or Sa,monella
Oxacillin and ampicillin or cefotaxime or chroamphenicol

37. Negative cultures Five of the six criteria to diagnose septic
arthritis: (Morey et al.)
Temp > c
Pain in suspected joint made worse by motion
Swelling of suspected joint
Systemic symptoms
Absence of other pathologic processes
A satisfactory response to antibiotic

38. Treatment Drainage Move the joint: to prevent intraarticular adhesions
Dislocated hip should be abducted to reduce it
Monitor serum bactericidal titers – changes to oral antibiotics at 1 wk
Abs for 3-6 wks when ESR returns to normal

39. Any child with spontaneous acute metaphyseal pain and tenderness
Never let the sun set
on pus under pressure
Any child with spontaneous acute metaphyseal pain and tenderness
has osteomyelitis until proven otherwise

40. Treatment Parenteral antibiotics
Duration of antibiotic – 2weeks to 4 months

41. Sequelae of Septic Arthritis of the Hip
Partial or complete destruction of the proximal femoral physis
Osteonecrosis of the femoral head
Trochanteric overgrowth
Pseudarthrosis of the femoral neck
Complete dissolution of the femoral neck and head
Progressive limb-length discrepancy
Varus or valgus alignment of the femoral head
Hip dislocation
Ankylosis of the hip joint

42. This is not so hard!

43. Bottom line
Early, accurate diagnosis of septic arthritis of the hip in children is critical
Poor outcomes with a delay in diagnosis
High degree of suspicion and Clinical judgement