Review Question - QID 392

There are multiple ways to assess final limb length. One way, the arithmetic method, assumes that girls and boys stop growing at 14 years of age and 16 years of age, respectively. Additionally, this method assumes a certain contribution from each physis to longitudinal annual growth:
Proximal femur – 4 mm per year
Distal femur – 10 mm per year
Proximal tibia - 6 mm per year
Distal tibia – 5 mm per year.
In this question, the boy has two years of growth remaining with a predicted arrest thru his distal femoral physis. Therefore, he will lose 20 mm or 2 cm of growth.

Zionts et al .discuss treatment considerations specific to pediatric knee fractures. They emphasize that although the use of appropriate treatment techniques may minimize the occurrence of late complications such as malunion and physeal bridging, not all problems are preventable. Thus, it is important to have a careful discussion of the injury with both patient and parents and stress the importance of follow-up so that any problems that do occur can be promptly addressed.

Stanitski et al reviews the therapeutic options for LLD. They state the indication for lengthening is a disparity exceeding 5 to 6 cm. Epiphysiodesis or limb shortening is useful for smaller discrepancies or for residual differences following a contralateral lengthening.