Case of femoral diaphyseal stress fracture after long-term risedronate administration diagnosed by iliac bone biopsy

Figures & data

Figure 1 Findings on imaging.

Notes: (A) Plain X-ray images show the apophysis of the bone on the lateral side of the femoral diaphysis. (B) Magnetic resonance T2-weighted fat-suppressed image shows the high signal intensity at the diaphysis. (C) Bone scintigraphy reveals an accumulation in the right femoral diaphysis.

Figure 2 MMA resin-embedded V bone stain.

Notes: A slight double-labeling of tetracycline can be observed. The trabeculae were narrow, and both osteoblasts and osteoclasts were decreased.
Abbreviations: MMA, methyl methacrylate; V bone, villanueva bone.

Table 1 Bone morphology measurement results

Parameter	Unit	Measurements	Normal value
Bone mass	%
Bone quality	%	14.99↑	11.0 ± 1.8
Trabecular bone width	μm	113.49↓	135.5 ± 7.5
Unit width trabecular bone	μm	Not measured	42.0 ± 2.0
The amount of osteoid tissue	%	0.33	0.1~1.0
Osteoid	%	2.2↑	1.6 ± 0.4
Osteoid bone mass
Osteoid surface	%	20.55↑	12.8 ± 2.2
Osteoid width	μm	5.96	6.4 ± 0.8
Absorption
Absorbing surface	%	3.79	3.0 ± 1.0
Osteoclast number	N/mm	0.28
The amount of fiber	%	0	0
Calcification
Bone calcification rate	μm/day	0.27↓	0.477 ± 0.078
Double-labeled surface	%	0.36
Dual-labeled surface	%	1.97
Bone formation rate (surface trabecular bone)	mm^3/mm^2/yr	0.001↓	0.01 ± 0.008
Bone formation rate (bone mass)	%/year	2.32↓	16.2 ± 12.5
Frequency activation	N/year	Not calculated	0.35

Notes: The data indicate that osteoid was increased and bone formation was decreased. Arrows show increase/decrease compared with normal value. Normal value is the mean ± standard deviation.