TABLE 2

Clinical and Radiographic Laboratory Findings in Children Undergoing Bone Biopsy

FindingAntibiotic Pretreatment Group, n = 40aNo Antibiotic Pretreatment Group, n = 27Statistical Variable, P or OR (95% CI)
Symptomsb
 Pain37/40 (93%)20/27 (74%)P = .08
 Fever38/40 (95%)27/27 (100%)P = .51
 Swelling20/22 (91%)9/13 (69%)P = .17
Signsb
 Tenderness33/37 (89%)22/24 (92%)P = .99
 Decreased range of motion25/27 (93%)15/19 (79%)P = .21
 Erythema18/29 (62%)5/14 (36%)P = .19
 Warmth19/23 (83%)9/12 (75%)P = .67
 Swelling30/34 (88%)13/18 (72%)P = .25
Laboratory findings, means
 WBC, cells/mm312 3009600P = .02
 Hemoglobin, g/dL11.811.4P = .14
 Platelets, cells/μL256 000352 000P < .001
 ESR, mm/h5352P = .84
 CRP, mg/L188P = .01
MRI findings,c n (%)
 Marrow edema23 (58)17 (63)0.8 (0.29–2.17)
 Myositis22 (55)12 (44)1.53 (0.57–4.08)
 Joint effusion24 (60)8 (30)3.56 (1.26–10.08)
 Periosteal reaction9 (23)4 (15)3.62 (0.72–18.34)
Histopathology
 Nonviable bone26/29 (90%)13/19 (68%)4 (0.86–18.6)
 Acute inflammation21/26 (81%)8/15 (53%)3.68 (0.90–15.01)
 Gram stain positive2/40 (5%)1 (4%)1.37 (0.12–15.89)
Blood culture, n (%)
 Positive22 (55)4 (15)7.03 (2.05–24.07)
 Negative18 (45)23 (85)
Bone biopsy Gram stain, n (%)
 Positive18 (45)7 (26)2.33 (0.81–6.76)
 Negative22 (55)20 (74)
Bone biopsy culture, n (%)
 Positive28 (70)17 (63)1.37 (0.49–3.86)
 Negative12 (30)10 (37)
  • Numbers may not sum to 100% due to rounding. CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; WBC, white blood cell count.

  • a Antibiotic pretreatment (number with positive cultures/number receiving antibiotic before bone biopsy): vancomycin 15/19 (79%), clindamycin 6/13 (46%), ceftriaxone 4/4 (100%), oral β-lactam 2/3 (67%), and nafcillin 1/1.

  • b Number with documented positive findings/number with finding documented.

  • c Many patients had >1 MRI finding.