NONINVASIVE IMAGING METHODS IN PAINFUL HIP ARTHROPLASTIES - CORRELATION OF PAIN WITH RADIONUCLIDE UPTAKE AND ULTRASONOGRAPHY IN CONSERVATIVELY MANAGED PATIENTS

The aim of our 1 year prospective study was to determine whether varia tion in clinical improvement in pain correlated with non-invasive imag ing and whether such correlation changed after conservative therapy. A total of 34 replacement hip arthroplasties in 31 patients with pain f ollowing surgery were studied by plain film, radionuclide bone scan an d ultrasonography. Changes in the different imaging methods and pain w ere compared after 1 year of conservative treatment. Twenty-two of the 34 painful arthroplasties had radiological evidence of loosening, eit her acetabular or femoral stem; 24 had positive bone scans, and 26 wer e positive by ultrasonography. A significant correlation was found bet ween pain and isotopic findings (r = 0.3518, p < 0.05, r = 0.3997, p < 0.05) and pain and ultrasonography (r = 0.4270, p < 0.05, r = 0.4276, p < 0.05), but not plain radiographs, both before and after therapy. No significant correlation was found between bone scans and ultrasonog raphic findings at the start of the study, but there was after 1 year of conservative treatment in radiologically positive cases (r = 0.4580 , p < 0.05). All but two of those 14 hips with radiologically loosened acetabular components had ultrasonographic evidence of effusion and a ll but one had a positive bone scan. Bone scans and ultrasonography we re positive in seven of 12 X-ray-negative hips. The results suggest th at non-invasive imaging techniques including conventional plain radiog raphs, 99m-technetium bone scintigraphy and ultrasonography are comple mentary in the evaluation and monitoring of patients with painful hip arthroplasties.