Fig 15. (A) Methylene blue-stained whole mount of a 50% defect three months after treatment with tissue extract.

The gap has been completely bridged by an irregular mass of cartilage, which appears to have regenerated primarily from the distal end of the fibula, with only a sliver regenerating from the proximal end (arrow). A cartilage bridge (asterisk), most likely derived from the tibial periosteum, connects the regenerating fibula to the tibia (T). (B) Methylene blue/alizarin red-stained whole mount of a 50% defect three months after treatment with tissue extract. The ends of the fibula were angled with respect to one another so that regeneration from the proximal and distal ends produced a V shape. A supernumerary foot (asterisk) regenerated perpendicular to the fibula. The star indicates the normal foot. Distal is toward the top; proximal is toward the bottom. F = femur; T = tibia; Fb = fibula.