AMPUTATING ABOVE THE KNEE

Prepare his thigh. Raise his leg so that you can prepare his upper thigh and groin. Put a drape behind it and another one in front.

Plan to leave 25 cm of his femur from the tip of his greater trochanter. If possible, make equal anterior and posterior flaps. If necessary, adapt them rather than amputating higher up. Start the anterior flap on the medial side of his thigh just proximal to the site of bone section. Curve it distally over the front of his thigh, to end on the lateral side opposite your starting point as in B, Fig. 56-11. Cut the posterior flap in a similar way. The combined length of the two flaps should be one and a half times the diameter of his thigh at the site of bone section.

Reflect the flaps to the site of section. Deepen the medial end of the anterior flap so as to expose his femoral artery underneath sartorius. Tie and divide his femoral artery and vein (3.6). Use two transfixion sutures for the artery. Begin the incision in his quadriceps along the line of the anterior flap, and bevel it proximally to the site of section, so as to make a muscle flap not more than 1.5 cm thick.

CAUTION! If you are operating for arterial disease and the muscles do not seem viable (56.3), be prepared to amputate higher up.

Ask your assistant to raise the patient’s leg while you cut across and bevel his posterior muscles distal to the site of section, in the same way as his anterior ones, so they retract to it. Trim away any excessively bulky muscle masses.

Find, clamp, and tie his profunda femoris artery on the posterior aspect of his femur adjacent to the linea aspera.

Find his sciatic nerve under his hamstring muscles, separate it from its bed without tension, pull it down, tie and cut it about 5 cm proximal to the end of his femur. Tie the artery that accompanies the sciatic nerve, but not the nerve itself.

CAUTION! The collateral vessels which accompany his sciatic nerve can bleed profusely.

Cut the periosteum all round his femur and saw it across immediately distal to this cut. Rasp away the prominence of the linea aspera and smooth the end of the bone.

Slowly release the tourniquet, and tie bleeding vessels as they appear.

Sew the anterior muscle flap over the end of the bone. Sew its fascia to the posterior fascia of his thigh. Trim away any excess muscle or fascia. Insert drains deep to this flap.

Cover the stump with a crepe bandage and then apply a plaster cap. This will relieve pain, and its weight will help to prevent a flexion contracture developing.

CAUTION! Don’t let a flexion contracture develop.

PROSTHESES FOR AN ABOVE KNEE AMPUTATION

If the patient is a long time waiting for his prothesis, pad his stump well, make a cast round it and fit it into a sawn off thinned down crutch. Keep it in place with more plaster bandages. This will enable him to walk until his permanent prothesis is ready.

If you have to amputate both a patient’s legs above his knees, consider the possibility of getting him short ’stumpy’ protheses for both his legs. He may prefer them to a wheel chair, and they will be easier to balance with than prostheses of the standard length. He will however walk closer to the ground, and need two short sticks. ’Stumpy’ prostheses are much easier to make, because they don’t have jointed knees, and need only be sockets with simple boots on. Keep them in place with cords over his shoulder.