Gallium-67 citrate as an aid to the diagnosis of infection in hip surgery.

We have evaluated the use of Gallium-67 scans as an aid to the diagnosis of infection around the hip joint after operation. We performed 12 gallium-67 scintiscans on six patients with diaphyseal fractures of the femur or tibia reduced by external fixation, and 65 scintiscans on 60 hips after operation, which included 22 Moore's prosthesis, 31 total replacements, three nail-plates and four revisions of total replacements. We also scanned the healing surgical wounds in a further 11 patients. Simple fractures or osteotomies did not lead to abnormal uptake of 67Ga. Although some uptake in the scar was encountered the surgical wound did not complicate the interpretation of the scan. When assessing infection in the hip operations the rate of true-positive was 11/11, or 100%. The false-positive rate could not be assessed until after at least one year's follow-up. It was certainly less than 14% immediately after operation and less than 6% when the scan was performed three months after operation. Four patients were found to have a loose prosthesis but had a normal scintiscan, as had three patients presenting with post-operative pain. It appears that 67Ga is clinically an efficient means for early detection of infection about the operated hip, and is useful in the differential diagnosis of a painful hip after surgery.