MRI diagnosis of occult hip fractures

Figures & data

A conventional radiograph interpreted as being negative. In retrospect, it may be possible to see an irregularity in the proximal cortex of the femoral neck.

A T1 weighted image with a subcapital femoral neck fracture as a black line with a somewhat vertical progression through the femoral neck.

An STIR image showing high signal areas surrounding the fracture (white and light gray) and extending towards the lesser trochanter, indicating a recent trauma.

Table 1.  Crosstable giving diagnoses after conventional radiography and the corresponding diagnoses after magnetic resonance imaging

	Conventional radiographs^a
Magnetic resonance imaging	A	B	C	D	E	F	G	H	Total
Negative	6^b	2			1				9
Femoral neck fracture	12	13							25
Incomplete fracture of femoral neck							1		1
Intertrochanteric fracture	10	1	6	3	1				21
Incomplete inter-trochanteric fracture	5								5
Isolated fracture of greater trochanter	3	1		6					10
Fracture of pubic rami	4	3	1			1			9
Acetabular fracture	2								2
Severe osteoarthritis		1					6		7
Malignant disease	2								2
Post traumatic soft tissue changes	8							1	9
Total	52	21	7	9	2	1	7	1	100

^a Conventional radiographs: A Negative B Suspicion of femoral neck fracture C Suspicion of intertrochanteric fracture D Isolated fracture of greater trochanter E Suspicion of fracture of greater trochanter F Suspicion of pelvic fracture G Severe osteoarthritis H Suspicion of osteolytic process ^b 1 false negative

Table 2.  MRI diagnoses given by radiologist A and B (both experienced musculoskeletal radiologists) in 23 randomly selected examinations. Differences in interpretation are marked with red

	Radiologist B
	Negative	Femoral neck fracture	Intertrochan- teric fracture	Fracture of pubic rami	Acetabular fracture
Radiologist A
Negative	5	1
Femoral neck fracture		6
Intertrochanteric fracture			5
Fracture of greater trochanter			3
Fracture of pubic rami				2
Acetabular fracture					1