What is leg length discrepancy after hip arthroplasty and how can it be minimized intraoperatively?

• A. A measurable difference in leg length postoperatively; minimize with preoperative templating, intraoperative measurement, use of trial components, and careful adjustment of offset/neck length
• B. The leg length discrepancy is impossible to measure intraoperatively
• C. LLD has no impact on function
• D. It can only be corrected with postoperative shoe modifications

Answer: (A)

Leg length discrepancy after hip arthroplasty is a measurable difference in the length of the legs that can occur after the operation and can affect gait and overall function. To minimize it during the procedure, thorough preoperative templating is used to plan the appropriate neck length and offset. Intraoperatively, trial components are placed so the surgeon can assess leg length, offset, and hip stability with the pelvis held level and the leg in a neutral position. If the length is off, adjustments are made by selecting different neck lengths or offsets, or by modifying how the cup and stem are positioned, with the goal of restoring equal leg length and normal offset before final components are implanted. Intraoperative verification, often with imaging or navigation, helps confirm that the leg lengths are matched and the hip is balanced. While postoperative shoe modifications can address residual minor discrepancies, the best way to minimize leg length discrepancy is active intraoperative planning and adjustments described above.