Common discrepancy are discrepancies present in the standard population. Up to 1/1000 people present a discrepancy over 6 cm, but several thousants of people present discrepancies from 2 to 6 cm.
Origins may vary, some being congenital (gradually increasing from birth, even if limited to only 2 cm at adulthood), others being mild forms of PFFD, and further ones being after trauma (generally 1 to 4 cm in femurs).
Treatment is obviously better with intramedullary nails. If some nails can address these pathologies (BetzBone, ISKD, Precice), the best one is the Guichet nail as it allows in such cases full return to sports from the first postoperative day (besides contact and impact sports). In addition, healing will progress fast in the Excellences Centers of Dr. Guichet, allowing to resume completely and fully all sports from the 3d or 4th postoperative month for discrepancies of 2 to 4 cm.
Pictures: A 14 Year-old patient who sustained a trauma resulting in a 5.5 cm discrepancy and a large varus deformity. She underwent an initial plate fixation with large scars. At 13 year-old, she got a correction of her varus deformity with an intramedullary nail then at 14 year-old, exchange of her trauma nail with a Guichet femoral nail and got full correction in less than 6 weeks. She could resume all sports during lengthening as the nail is strong for her body. X-rays with the nail show the healing at 6 weeks. She was fully fused one month later.