Objective: To evaluate the contribution of laboratory tests, histology and scintigraphy for diagnosing and monitoring the treatment of lower limb arthroplasty infection.
Patients and methods: 37 lower limb arthroplasties, 20 at the hip and 17 at the knee, were studied. Investigations included laboratory tests for inflammation (erythrocyte sedimentation rate, C-reactive protein, haptoglobin, and orosomucoid), histology (presence of neutrophils) and scintigraphy (99m Tc-HMDP bone scan, colloidal sulfide bone marrow scan, and 99m Tc-HMPAO leukocyte scan). Follow-up was at least three years after treatment of the infection.
Results: Acute phase reactants were more sensitive and more specific than the erythrocyte sedimentation rate. The full scintigraphy protocol had 100% sensitivity and 87% specificity. Recovery of neutrophils by aspiration or during surgery was 100% specific in the absence of hematomas or rheumatoid arthritis. Sensitivity of the presence of neutrophils varied with the collection technique.