An above-knee amputee fitted with a new prosthesis walks with the prosthetic leg swinging outward in a wide arc around the side during every step instead of moving forward in a straight line. Which prosthetic fault best explains this gait deviation?

• A The prosthesis is too short compared with the sound limb
• B The socket fits loosely and pistons during swing phase
• C The prosthesis is too long compared with the sound limb ✓
• D The knee friction brake is set too low

Explanation

Circumducted gait in a transfemoral amputee occurs when the prosthesis is too long: the toe cannot clear the floor in a straight swing, so the patient arcs the limb laterally through a semicircle. Excessive knee friction producing poor knee flexion in swing gives a similar appearance, but among the options given only excessive length directly causes the described wide lateral arc. A short prosthesis produces a dip of the pelvis and lateral trunk bending toward the amputated side instead.

Reference: Apley and Solomon's System of Orthopaedics and Trauma, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.