Previously unexplored etiology for femoral head necrosis: Metagenomics detects no pathogens in necrotic femoral head tissue

Table 1 Characteristics of patients with idiopathic osteonecrosis of the femoral head

Case	Sex/age (yr)	Site	Comorbidities	Physical examination	X-ray features	Ficat stage	Time from pain onset to admission	Surgical approach	Outcome
1	M/50	Bilateral	Lumbar disc herniation	Limb gait, Harris score: 25 (left), 19 (right), left hip joint mobility: flexion 90°, extension 0°, abduction 15°, adduction 10°, external rotation 0°, internal rotation 10°, right hip joint mobility: flexion 90°, extension 0°, abduction 10°, adduction 0°, external rotation 0°, internal rotation 0°, Thomas experiment (+), Patrick experiment (+)	Bilateral femoral head collapse, crescent sign, joint space narrowing, with hip osteoarthritis	IV (left); IV (right)	2 yr	Bilateral artificial total hip arthroplasty	Harris score: 48 (left), 47 (right)
2	F/62	Left	None	Limb gait, Harris score: 35, hip joint mobility: flexion 90°, extension 5°, abduction 20°, adduction 15°, external rotation 15°, internal rotation 5°, Thomas experiment (+), Patrick experiment (+)	Femoral head collapse occurs, crescent sign	III	7 mo	Left artificial total hip arthroplasty	Harris score: 52
3	F/68	Left	None	Limb gait, Harris score: 35, hip joint mobility: flexion 70°, extension 0°, abduction 10°, adduction 10°, external rotation 10°, internal rotation 10°, Thomas experiment (+), Patrick experiment (+)	Femoral head collapse occurs, crescent sign	III	2 mo	Left artificial total hip arthroplasty	Harris score: 54
4	F/69	Right	None	Limb gait, Harris score: 17, hip joint mobility: flexion 60°, extension 0°, abduction 0°, adduction 0°, external rotation 0°, internal rotation 5°, Thomas experiment (+), Patrick experiment (+)	Femoral head collapse occurs, crescent sign	IV	15 mo	Right artificial total hip arthroplasty	Harris score: 48
5	M/48	Bilateral	None	Limb gait, Harris score: 24 (left), 37 (right), left hip joint mobility: flexion 90°, extension 0°, abduction 40°, adduction 10°, external rotation 15°, internal rotation 10°, right hip joint mobility: flexion 110°, extension 0°, abduction 60°, adduction 15°, external rotation 15°, internal rotation 15°, Thomas experiment (+), Patrick experiment (+)	Femoral head collapse occurs, crescent sign (left); No femoral head collapse, appear cystic (right)	III (left); II (right)	15 mo	Left artificial total hip arthroplasty	Harris score: 56 (left), 37 (right)
6	F/63	Left	Lumbar disc herniation and lumbar spinal stenosis	Limb gait, Harris score: 32, hip joint mobility: flexion 70°, extension 0°, abduction 25°, adduction 10°, external rotation 10°, internal rotation 10°, Thomas experiment (+), Patrick experiment (+)	Femoral head collapse, joint space narrowing	IV	3 yr and 6 mo	Left artificial total hip arthroplasty	Harris score: 49
7	M/61	Left	Prostatic hyperplasia, bronchitis	Limb gait, Harris score: 45, hip joint mobility: flexion 100°, extension 0°, abduction 20°, adduction 10°, external rotation 15°, internal rotation 10°, Thomas experiment (+), Patrick experiment (+)	Femoral head collapse occurs, crescent sign	III	5 yr	Left artificial total hip arthroplasty	Harris score: 55
8	M/56	Right	None	Limb gait, Harris score: 30, hip joint mobility: flexion 80°, extension 10°, abduction 15°, adduction 5°, external rotation 0°, internal rotation 5°, Thomas experiment (+), Patrick experiment (+)	Femoral head collapse occurs, crescent sign	IV	16 mo	Right artificial total hip arthroplasty	Harris score: 51
9	F/62	Left	None	Limb gait, Harris score: 40, hip joint mobility: flexion 90°, extension 10°, abduction 15°, adduction 5°, external rotation 10°, internal rotation 15°, Thomas experiment (+), Patrick experiment (+)	Femoral head collapse occurs, crescent sign	III	5 mo	Left artificial total hip arthroplasty	Harris score: 57
10	M/46	Bilateral	None	Limb gait, Harris score: 26 (left), 28 (right), left hip joint mobility: flexion 85°, extension 10°, abduction 35°, adduction 15°, external rotation 10°, internal rotation 10°, right hip joint mobility: flexion 90°, extension 10°, abduction 25°, adduction 10°, external rotation 10°, internal rotation 15°, Thomas experiment (+), Patrick experiment (+)	Bilateral femoral head collapse, crescent sign	III (left); III (right)	3 yr	Bilateral artificial total hip arthroplasty	Harris score: 46 (left), 48 (right)
11	F/55	Left	None	Limb gait, Harris score: 40, hip joint mobility: flexion 95°, extension 15°, abduction 15°, adduction 20°, external rotation 10°, internal rotation 10°, Thomas experiment (+), Patrick experiment (+)	Femoral head collapse occurs, crescent sign	III	9 mo	Left artificial total hip arthroplasty	Harris score: 58
12	M/61	Left	None	Limb gait, Harris score: 22, hip joint mobility: flexion 65°, extension 0°, abduction 5°, adduction 0°, external rotation 5°, internal rotation 0°, Thomas experiment (+), Patrick experiment (+)	Femoral head collapse occurs, crescent sign	IV	4 yr	Left artificial total hip arthroplasty	Harris score: 46