Cooper broke his leg when he was 2-to-3 weeks old.

"They were going to put him down because of the broken leg," said Sally Stoffel.

Stoffel saw a picture of Cooper, fell in love and agreed to adopt Cooper despite his injury.

For weeks, Cooper walked on three legs. But Stoffel took Cooper to CSU to see if something could be done to help him.

"He was compensating well," said CSU small animal orthopedic surgeon Ross Palmer. "One of the things we did discuss was whether an amputation was a suitable thing to do for him. He was a happy dog, but his limb was becoming a limitation for him."

Palmer decided to try surgery. A colleague in Italy loaned Palmer a human orthopedic device that is not available in the United States. The device permits surgeons to correct complex bony angular deformities and has a mechanism for gradual stretching of the healing bone.

Palmer used the device to straighten and lengthen Coopers broken leg.

Palmer stretched Cooper's leg two millimeters a day.

"We tried three millimeters a day, but that seemed a bit much, so we went back down to two millimeters a day," said Palmer. "Toward the end we backed down to one millimeter a day."

In all, the technique grew Cooper's tibia 76 millimeters -- or about three inches. Thirty-six millimeters were added as a function of the corrective surgery and 40 millimeters were developed from daily adjustments performed on Cooper by Stoffel over one month. Once the device's maximal safe lengthening limit was attained, the bone was allowed to mend itself.

"It has been well worth it," said Stoffel. "We went from a leg that was just a mangled lump that he had stopped using, muscles had completely atrophied, to what you see now."

Palmer said he will monitor Cooper's limb growth, gait and posture to assess whether or not he will eventually need to be fitted with a prosthetic lift shoe on his leg or if a second bone lengthening procedure will be needed to make up for a discrepancy in limb length.