[Relationship between tibia callus diameter ratio and prognosis during tibia lengthening].

OBJECTIVE

To investigate the relationship between the tibia callus diameter ratio (CDR) and prognosis during tibial distraction and the occurrence of late deformity or fracture.

METHODS

We measured tibial lengthening callus diameter and added up the cases of angular deformity and fracture in 68 cases from January 1996 to December 2001, to calculated callus diameter ratios and compare the relationship between the tibia callus diameter during tibial distraction and the occurrence of late callus angular deformity or fracture.

RESULTS

In 23 cases of CDR < 80%, 13 cases had new bone fracture, 21 cases had angular deformity > 5 degree. In 6 cases of 81% < CDR < 85%, there were 4 cases of angular deformity > 5 degree. In the other 39 cases of CDR > 85%, there were no fracture and angular deformity.

CONCLUSION

When the CDR was > 85%, there were no angular deformity and fracture, but when the CDR was < 80%, the complications of fracture and angular deformity occur. CDR is a better alarming index for preventing the complications occurring in tibial lengthening.