Frank Gottschalk, M.D.

Despite improvements in prosthetic design and fabrication, artificial limbs are unable to provide a reasonable replacement for the lost limb when poor surgery has been performed, and an inadequate residual limb has been created. Too often, transfemoral amputations are performed without thought for biomechanical principles and/or preservation of muscle function.

In most transfemoral amputees, mechanical and anatomic alignment is disrupted since the residual femur no longer has its natural anatomic alignment with the tibia, leaving the femoral shaft-axis in abduction. In addition, the major portion of the adductor insertion is lost in conventional transfemoral amputations. Only the adductor magnus has an insertion on the mediodistal third of the femur. Once this attachment is lost at the time of surgery, the femur swings into abduction because of the relatively unopposed action of the abductor system. The abducted femur of the transfemoral amputee leads to an increase in side lunch and higher energy consumption. In the majority of transfemoral amputees who have had a conventional surgical procedure, the energy expenditure will be 65% or more above normal for level walking at a regular walking pace.

The goal, when performing transfemoral amputation, should be the creation of a dynamically balanced residual limb, with good motor control and nerve sensation. Preservation of the adductor magnus is possible, and helps maintain the muscle balance between the adductors and abductors. The retained muscle bulk allows the adductor magnus to maintain close to normal muscle power and a better advantage for holding the residual femur in the normal anatomic position. This should allow the amputee to function at a more normal level and use a prosthesis with greater ease.

References
1. Atlas of Limb Prosthetics: Surgical, Prosthetic, and Rehabilitation Principles, AAOS Mosby Yearbook 1992:Chapter 20

• Total Run Time: 17:17 minutes
• Catalog Number: 6011
• Publication Date: August 1993

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