Your doctor may order a bone length study if they suspect you have limb length discrepancy (LLD). Although no one's limbs are precisely symmetrical, some may have significant differences in leg length. Although some patients do not show symptoms, others have symptoms such as:
- Knee or hip pain on one or both sides
- Back pain
- Getting tired from walking too quickly
Before ordering a bone length study X-ray, your doctor may request a physical exam to evaluate limb length. A woodblock test is commonly used to measure the discrepancy physically. Wood blocks are added under the shorter leg of the upright patient until the pelvis is level. Then the blocks are counted to find the difference. However, X-rays give a much more accurate result of the discrepancy. It's essential to know the apparent disparity in length before a treatment plan is finalized. If a leg length discrepancy is confirmed, your doctor may recommend that you should repeat the X-ray at regular intervals in time. This is done to see if the difference is more significant or to monitor treatment effects.