A 70-year-old woman with a transfemoral amputation is being fitted for a prosthesis. The optimal length of the residual femur for best prosthetic function is:
- A As long as possible — femur should be transected just proximal to the condyles
- B 50–60% of femoral length from the greater trochanter ✓
- C At the junction of the upper and middle thirds
- D Transected at the level of the lesser trochanter for maximum adductor control
Correct answer: B. 50–60% of femoral length from the greater trochanter
Explanation
The optimal transfemoral residual limb length is 50–60% of the total femoral length (measured from the greater trochanter), which preserves adequate muscle leverage (hip abductors, adductors, extensors) for prosthetic control while allowing space in the prosthetic socket for the knee unit to be aligned symmetrically with the contralateral natural knee. Very short stumps (<30%) lose adductor and hip extensor control, producing hip flexion-abduction contracture. Very long stumps may interfere with polycentric or microprocessor knee unit placement.
Reference: Maheshwari Essential Orthopaedics, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.