It is easy to overcome the difficulty by attaching the leg by two independent lateral hinge joints, without a bolt right through, using the stirrup-shaped fork and the double lock, if a peg is used. This method, as we have already stated, is not so strong, but this is to a large extent compensated for by the possibility of getting a direct end bearing.
3. Direct end bearing and suspension.—If the stump is well covered with a good anterior flap and if the lower end of the bucket is accurately moulded upon it with an interposed layer of felt, the patient can walk directly upon the end of the stump, without it being necessary to carry the bucket up against the ischium, simple braces being used as the means of suspension.
4. There is nothing special about the braces or about the extending strap if the knee is free, nor about the method of attaching the foot.
These limbs for long stumps do not require any spring to extend the knee, if one is wanted an artificial muscle is quite easily fitted.
We have taken as our type an amputation through the femoral condyles.
The covering of the stump is excellent, and pressure is taken upon tissues which are naturally adapted to it (the thick skin and fibrous tissue over the patella), specially if it has been possible to keep the patella in the flap and fix it across the cut surface of the femur (Gritti's operation).
The mechanical points in the fitting of an artificial limb for an amputation through the knee joint are the same. But this amputation seems to us to be inferior to that through the condyles. The sacrifice of three centimetres in length is of no importance in an appliance with direct end bearing; and, on the other hand, disarticulation has several disadvantages:—
1. The enlargement of the femoral condyles, without any compensating advantage.
2. The bearing upon the two condyles, separated by a groove.
3. The insufficient covering of the condyles by the thin skin of the front of the leg.