Tc-99m-HDP Pinhole Bone Scintigraphy in Osteonecrosis of the Femoral Head Treated with Free Vascularized Fibular Graft
HM Kim, KH Lee, CH Jeong, CW Moon, YS Kim
Department of Orthopaedic Surgery, Holy Family Hospital, College of Medicine
The Catholic University of Korea, Seoul, Korea

It is very important to evaluate a healing process in femoral head after free vascularized fibular graft (VFG) in osteonecrosis of the femoral head (ONFH). Bone scintigraphy combined with pinhole collimater which is simple and not expensive, is used for very high resolution images of small organs, such as thyroid and certain skeletal region. The purpose of this study was to assess the changes of pinhole bone scintigraphy in ONFH after VFG. Authors analyzed changes of Tc-99m-HDP pinhole bone scintigraphy in the 22 cases of ONFH which were treated with VFG and showed satisfactory results at least 2 year follow-up after the surgery; namely, Harris Hip Score was 90 or more; and femoral head collapse was less than 2 mm. The results were (1) At 1 week, the pinhole image showed no significant change in cold area but two linear RI uptake correspond to fibular graft were noted. (2) At 3 months, localized hot uptake just above tip of graft were observed in 17 cases (77.2%), and diffuse increased uptake surround the cold area were observed. (3) At 6 months, localized hot uptake were increased in size and replaced cold area and delineated the shape of superolateral aspect femoral head. (4) At 1 year, increased RI uptake of superolateral aspect of femoral head expanded medially in all cases. (5) After 2 years, cold area fades away in 18 cases (81.8%). In conclusion, we believe that the Tc-99m-HDP pinhole bone scintigraphy is an excellent method to represent the healing process in ONFH after VFG.