Limb-length discrepancy can be due to many causes. These are divided into three groups: congenital (from birth), developmental (from a childhood disease or injury that slows or damages the growth plates), and posttraumatic (from a fracture that leads to shortening of the bone ends). There are three ways to equalize the limb-length discrepancy: use a shoe lift, shorten the long leg, lengthen the short leg. Most patients do not like wearing a lift greater than 2 cm (3/4 in). For discrepancies greater than 2 cm but less than 5 cm (2 in), shortening of the long leg can be considered, especially for tall persons. For growing children, this can be easily accomplished with a small, minimally invasive, uncomplicated procedure called epiphysiodesis.The investigators aim to evaluate if injection of bone marrow derived mesenchymal stem cells can shorten the treatment period by acceleration of bone regeneration during distraction osteogenesis.

Distraction osteogenesis has been widely utilized to treat leg length discrepancy, deformity, nonunion, osteomyelitis, and bone loss. It has been found that most difficult conditions can be resolved with this method. In this study the aim is to observe if mesenchymal stem cell transplantation can enhance new bone formation during distraction osteogenesis.Patients undergo bone distraction , and about 2-3 weeks after distraction mesenchymal stem cell are injected at the callus site. In the case of large bone gap, mesenchymal stem cells are seeded on bone matrix and then placed in the bone gap. Each patient is assessed at interval time of 1 month for 6 months post surgery by X-Ray and at month 6 post surgery by computed tomography(CT) scans.

Inclusion Criteria:

• both gender
• patient with limb-length discrepancy
• Age:18-65

Exclusion Criteria:

• Diagnosis of cancer,DM,CNS disorder,thyroid disease or respiratory disease
• Known allergic reaction to components of study treatment and/or study injection procedure
• Patients infected with hepatitis B,C or HIV
• pregnancy