Specialty Update What’s New in Limb Lengthening and Deformity Correction

Limb-Length Discrepancy and Lower Limb Alignment The minimum threshold for treating limb-length discrepancy is debatable. In the study by O’Brien et al., an imposed discrepancy of >10 mm was perceived by twenty-nine (97%) of thirty normal subjects1. In the study by Golightly et al., an inequality of ‡20 mm was associated with progressive radiographic osteoarthritis of the knee2. There are subtle differences in lower limb alignment based on sex3 and ethnicity4. Measuring the anatomic axis of the femur and tibia in patients with osteoarthritis with use of limited radiographs of the knee may be less reliable than a fulllength weight-bearing radiograph of the lower extremity5. A comprehensive monograph on the treatment of limb-length discrepancies was recently published6.