Differences in magnetic resonance findings between symptomatic and asymptomatic pre-collapse osteonecrosis of the femoral head. Issue 112 (March 2019)

• Record Type: Journal Article
• Authors: Hatanaka, Hiroyuki; Motomura, Goro; Ikemura, Satoshi; Kubo, Yusuke; Utsunomiya, Takeshi; Baba, Shoji; Kawano, Koichiro; Nakashima, Yasuharu
• Is Part Of: European journal of radiology. Issue 112(2019)
• Page Start: 1
• Page End: 6
• Publication Date: 2019-03
• Subjects: ONFH osteonecrosis of the femoral head -- MR magnetic resonance -- BME bone marrow edema; Osteonecrosis -- Pre-collapse -- Bone marrow edema; Medical radiology -- Periodicals; Radiology -- Periodicals; Radiologie médicale -- Périodiques; Medical radiology; Periodicals; 616.075705
• DOI: 10.1016/j.ejrad.2019.01.002
• Languages: English
• ISSNs: 0720-048X

Abstract

Highlights: Symptomatic and asymptomatic pre-collapse stage of ONFH differs on MR imaging despite almost the same radiographic findings. Symptomatic pre-collapse stage of ONFH could be distinguished from asymptomatic disease by the presence of BME on MR imaging. The post-MR clinical course was quite different between symptomatic and asymptomatic pre-collapse stage of ONFH. Abstract: Purpose: The purpose of this study was to assess the differences in magnetic resonance (MR) findings between the symptomatic and asymptomatic pre-collapse stage of osteonecrosis of the femoral head (ONFH). Materials and methods: This study reviewed 123 consecutive hips in 91 patients in the pre-collapse stage of ONFH based on plain radiographic findings. These 123 hips were divided into symptomatic and asymptomatic groups according to the pain domain score in the Harris hip score system. Bone marrow edema (BME), synovial fluid effusion, and subchondral fracture were evaluated using MR imaging. Odds ratios (ORs) were calculated between these three parameters and symptoms. The subsequent clinical course after MR examination was also assessed for each hip that could be followed more than 1 year. Results: Forty-six hips (37.4%) were categorized as symptomatic and 77 hips (62.6%) as asymptomatic. The prevalence of BME, synovial fluid effusion, and subchondral fracture were 87.0% (40/46), 80.4% (37/46), and 34.8% (16/46), respectively, in the symptomatic group, and 0%, 28.6% (22/77), and 0%, respectively, in the asymptomatic group, indicating significant differences between the two groups (p < 0.0001). Among these parameters, BME showed the highest OR with regard to the presence or absence of symptoms (BME, 965.8; joint effusion, 10.3; subchondral fracture, 83.9). Due to persistent pain and subsequent collapse, 30 of 35 (85.7%) symptomatic hips with BME subsequently underwent surgical treatment at a mean interval of 3.47 months after MR examination, while 25 of 66 (37.9%) asymptomatic hips without BME underwent surgical treatment at a mean interval of 20.7 months after MR examination. Conclusions: This study demonstrated that symptomatic pre-collapse ONFH diagnosed based on plain radiographic findings could be distinguished from asymptomatic pre-collapse ONFH by the presence of BME on MR imaging, and thus BME may be a sign of occult fracture.