Abstract：
OBJECTIVE: Transient osteoporosis of the hip (TOH) is an uncommon, typically self-limited diagnosis of uncertain etiology. We hypothesize that TOH represents an underlying subchondral fracture, and a discrete fracture line can often be detected on high-resolution MRI.
METHODS: A retrospective PACS query identified patients meeting imaging criteria for TOH with intense bone marrow edema (BME) in the femoral head on MRI. Those with poor quality studies, other underlying pathologies, or antecedent trauma were excluded. Three musculoskeletal radiologists independently reviewed each case for presence of a definite subchondral fracture line on small field of view (FOV) MR images of the affected hip. Extent of BME, reciprocal acetabular BME, and joint effusion size were also recorded. Binomial logistic regression was performed to determine statistically significant predictors of subchondral fracture.
RESULTS: Fifty patients met inclusion criteria (29 females, 0 pregnant). Mean age was 62±12 years (range 35-84). Average duration of symptoms before MRI was 102±135 days. Ten patients had bone densitometry within 2 years of MRI, six demonstrating osteopenia or osteoporosis. Subchondral fractures were unanimously identified in 44/50 (88%). Interclass correlation coefficient with absolute agreement was 0.73, 95% CI (0.57-0.84), indicating near-excellent agreement. Most cases demonstrated a large joint effusion (23/50, 46%) and acetabular BME (31/50, 62%). Increasing size of joint effusion was a statistically significant predictor of subchondral fracture (p=0.05), with 6.9 higher odds. There was a strong correlation with osteopenia/osteoporosis and fracture (p<0.001).
CONCLUSIONS: Discrete subchondral fractures were identified unanimously on small FOV imaging in the majority of TOH cases.
METHODS: A retrospective PACS query identified patients meeting imaging criteria for TOH with intense bone marrow edema (BME) in the femoral head on MRI. Those with poor quality studies, other underlying pathologies, or antecedent trauma were excluded. Three musculoskeletal radiologists independently reviewed each case for presence of a definite subchondral fracture line on small field of view (FOV) MR images of the affected hip. Extent of BME, reciprocal acetabular BME, and joint effusion size were also recorded. Binomial logistic regression was performed to determine statistically significant predictors of subchondral fracture.
RESULTS: Fifty patients met inclusion criteria (29 females, 0 pregnant). Mean age was 62±12 years (range 35-84). Average duration of symptoms before MRI was 102±135 days. Ten patients had bone densitometry within 2 years of MRI, six demonstrating osteopenia or osteoporosis. Subchondral fractures were unanimously identified in 44/50 (88%). Interclass correlation coefficient with absolute agreement was 0.73, 95% CI (0.57-0.84), indicating near-excellent agreement. Most cases demonstrated a large joint effusion (23/50, 46%) and acetabular BME (31/50, 62%). Increasing size of joint effusion was a statistically significant predictor of subchondral fracture (p=0.05), with 6.9 higher odds. There was a strong correlation with osteopenia/osteoporosis and fracture (p<0.001).
CONCLUSIONS: Discrete subchondral fractures were identified unanimously on small FOV imaging in the majority of TOH cases.
摘要：
目的：短暂性髋部骨质疏松（TOH）并不常见，典型的自我限制诊断不确定的病因。我们假设TOH代表潜在的软骨下骨折，并且在高分辨率MRI上通常可以检测到离散的骨折线。
方法：回顾性PACS查询确定了符合TOH影像学标准的患者，在MRI上有强烈的股骨头骨髓水肿（BME）。那些学习质量差的人，其他潜在的病理，或先前的创伤被排除。三名肌肉骨骼放射科医生在受影响的髋关节的小视野（FOV）MR图像上独立检查了每种情况下是否存在明确的软骨下骨折线。BME的程度,往复髋臼BME，并记录关节积液的大小。进行二项逻辑回归以确定具有统计学意义的软骨下骨折预测因子。
结果：50名患者符合纳入标准（29名女性，0怀孕）。平均年龄为62±12岁（范围35-84）。MRI前症状的平均持续时间为102±135天。10例患者在MRI2年内进行了骨密度测定，六例显示骨质减少或骨质疏松症。在44/50（88％）中一致确定了软骨下骨折。具有绝对一致性的类间相关系数为0.73，95%CI(0.57-0.84)，表明近乎极好的协议。大多数病例表现为大量关节积液（23/50，46％）和髋臼BME（31/50，62％）。关节积液的增大是软骨下骨折的统计学显著预测因素(p=0.05),赔率高6.9。与骨量减少/骨质疏松和骨折有很强的相关性(p<0.001)。
结论：在大多数TOH病例中，小FOV成像一致发现了离散的软骨下骨折。
方法：回顾性PACS查询确定了符合TOH影像学标准的患者，在MRI上有强烈的股骨头骨髓水肿（BME）。那些学习质量差的人，其他潜在的病理，或先前的创伤被排除。三名肌肉骨骼放射科医生在受影响的髋关节的小视野（FOV）MR图像上独立检查了每种情况下是否存在明确的软骨下骨折线。BME的程度,往复髋臼BME，并记录关节积液的大小。进行二项逻辑回归以确定具有统计学意义的软骨下骨折预测因子。
结果：50名患者符合纳入标准（29名女性，0怀孕）。平均年龄为62±12岁（范围35-84）。MRI前症状的平均持续时间为102±135天。10例患者在MRI2年内进行了骨密度测定，六例显示骨质减少或骨质疏松症。在44/50（88％）中一致确定了软骨下骨折。具有绝对一致性的类间相关系数为0.73，95%CI(0.57-0.84)，表明近乎极好的协议。大多数病例表现为大量关节积液（23/50，46％）和髋臼BME（31/50，62％）。关节积液的增大是软骨下骨折的统计学显著预测因素(p=0.05),赔率高6.9。与骨量减少/骨质疏松和骨折有很强的相关性(p<0.001)。
结论：在大多数TOH病例中，小FOV成像一致发现了离散的软骨下骨折。
