HIP · LEG LENGTH · JOINT HEALTH JOURNAL
Unequal legs after hip replacement? How DAA helps manage leg length
Concern about unequal legs is understandable when planning a hip replacement. A difference may already exist before surgery. The direct anterior approach (DAA) can facilitate intraoperative comparison and measurement, but cannot guarantee perfectly equal leg lengths.
First identify where the difference comes from
Unequal legs may relate to development, an old fracture or joint disease. Pelvic tilt or joint contracture can also create an apparent difference. Assessment combines posture, gait, examination and, when needed, standing full-length X-rays.
Different sources of unequal leg length
How can DAA help control leg length?
DAA is usually performed with the patient lying on their back, allowing leg comparison and optional imaging. Planning and measurements help manage length. A 2024 review found fewer differences over 1 cm in DAA comparison studies, but mostly low-level evidence does not establish a guarantee.
Three parts of leg-length planning
Leg length and hip stability both matter
Hip replacement must restore function and stability as well as length. Surgeons balance these goals and soft-tissue tension. If one leg feels longer afterwards, report it at follow-up. Examination guides observation, rehabilitation or consideration of a shoe lift. DAA does not treat every cause of unequal legs.
Plan for overall function
Frequently asked questions
Who assesses unequal leg lengths?
An orthopaedic clinician can assess leg length, the pelvis and joints. For concerns after hip replacement, start with your operating surgeon.
Does DAA guarantee equal legs?
No. Positioning and measurement can help control discrepancy, but anatomy, planning and stability requirements still matter.
Care includes soft-tissue preservation when appropriate and support through recovery. Bring previous imaging and describe when the difference began and which activities are uncomfortable.
General education does not replace individual assessment. Diagrams illustrate concepts, not a diagnosis or guaranteed result.