For the general method, see Section 56.1.
ANAESTHESIA It is a great help to be able to turn the patient onto his face, so a low subarachnoid anaesthetic (A 7.6) is suitable. If you cannot anaesthetize him lying on his face, bend his knee over the end of the table.
PREPARATION Wash, shave, and paint the operation site. Apply a tourniquet. As soon as he is anaesthetized, raise his leg steeply for a few minutes to drain the blood from it. Then bow up the tourniquet. Wrap his foot securely in a sterile towel.
Mark out the flaps.
Line ’A’ is the site of bone section 8 to 14 cm distal to his tibial tubercle, 12 cm is optimal. This is about the length of your index finger, with the base of your second metacarpal on his tibial tubercle.
Line ’B’ is 2 cm distal to ’A’, and marks the point where the flaps divide anteriorly.
Line ’C’ marks the distal extent of the flaps.
If you are not certain of the geometry of the flaps, cut them too long rather than too short.
Cut through the patient’s skin, his subcutaneous tissue, and his deep fascia. Cut through the periosteum on the anterior surface of his tibia.
Raise two medial and lateral semicircular flaps to include the skin, subcutaneous tissue, deep fascia and the periosteum on the front of his tibia. Reflect them proximally for 2 cm only.
Divide the underlying muscle at this level, and tie the major vessels as you meet them.
Cut an oblique notch in the front of the tibia, then saw through it at line ’A: The notch will be easier to make, if you saw it before you saw through the tibia.
Saw through the fibula obliquely 1 to 3 cm higher up.
Raise his leg, remove the tourniquet, find and tie the remaining vessels. Suture the fascia with interrupted monofilament sutures.
Don’t try to suture the muscles. They are still attached to the deep fascia, and should fall neatly into place under the sutured layer of deep fascia.
CAUTION! If there are any of the indications for delayed primary suture, as listed Section 56.1, this would probably be wiser. Otherwise, closehis skin with interrupted monofilament sutures. Leave any dog ears.
If you have done a neat job, there should be no dead spaces in which a haematoma can collect. If you are not confident that you have eliminated any dead spaces, insert a drain.
Cover the stump, including the patient’s knee, with generous gauze pads, and apply a firm pressure dressing. Mould a thin plaster shell round the stump, including the distal part of his thigh, with his knee fully extended, or apply a backslab. This is an effective way of preventing a flexion contracture.
Day 3. Keep the stump elevated. Start quadriceps exercises.
Day 14. Remove the plaster shell and the sutures. Bind the stump with a tight bandage. Start’ active knee exercises against resistance.
Day 28. Fit him with his first prosthesis.
CAUTION! Watch for and prevent a flexion contracture, because it will prevent a prosthesis being fitted. If you are too late to prevent it, the best treatment may be to cut the stump even shorter, to allow the contacture to become even more severe, and then to fit a peg leg.
