Saber Tibia in Paget’s Disease of Bone

This post is an answer to the Case – Long-Standing, Painful Deformation of the Right Tibia

Physical examination revealed a prominent saber-like tibia and superficial venous circulation related to chronic venous insufficiency (image below, Panel A). Radiographs showed cortical thickening, trabecular enlargement, and bowing of the tibia (Panel B shows the anteroposterior view and Panel C the lateral view).

Saber Tibia in Paget's Disease of Bone
Saber Tibia in Paget’s Disease of Bone

Levels of bone turnover markers were increased, including an alkaline phosphatase level of 345 U per liter (normal range, 45 to 129), an N-terminal propeptide of type I procollagen (P1NP) level of 506.3 ng per milliliter (normal value, <36.4), and a level of the β-isomer of the C-terminal telopeptide of type I collagen (β-CTX) of 1.38 ng per milliliter (normal value, <0.30). These findings show the clinical sequelae of prolonged early-onset Paget’s disease of bone.

Zoledronate at a single dose of 5 mg was prescribed owing to the increased metabolic activity in a weight-bearing location. Near-normalization of the alkaline phosphatase level (69 U per liter), the P1NP level (40.6 ng per milliliter), and the β-CTX level (0.34 ng per milliliter) was seen after 1 year, with symptomatic improvement.