B. Age of Patient.—It must be remembered that excision in a child removes the epiphyses by which in great measure the growth of the bone is to be managed, and the stunted limb, especially in the leg, will eventually be of little advantage, though after the operation it looked excellently well, if a few years later it be found to be seven or eight inches shorter than its neighbour.
C. Amount of Bone removed.—From an erroneous view of the pathological changes in the bone affected, far too much was removed by many of the earlier operators, especially Moreau and Crampton.
The reason that this is often still the case, is well seen in many preparations. The bones are thickened to a considerable distance, and covered with irregular warty excrescences. These, which used to be considered evidences of disease, are only compact new healthy bone, thrown out like the callus of a fracture in consequence of the irritation.
In a word, what we require to remove is the following:—
1. All the cartilage, dead or alive, healthy or diseased.
2. Only the bone involving the articular extremities, in thin slices, or with the occasional use of the gouge, till a healthy bleeding surface is obtained.
3. The synovial membrane, however gelatinous or thickened looking, really requires very little care or notice; it will disappear of itself, partly by sloughing, partly by absorption during the profuse suppuration.[53]
Excision of the Shoulder-Joint.—Before considering the method of operating, a word or two is required on the subject of how much is to be removed, and in what cases the operation should be performed. The shoulder and hip joints are the only ones in which partial excision is ever admissible, indeed, in the shoulder excision of the head of the humerus only is in many cases found to be all that is necessary, while in all it is much less dangerous to life than when the glenoid cavity also requires to be interfered with.
It is rarely necessary to remove more of the bone than merely its articular extremity (when performed for disease of the joint), and if possible this should be done inside the capsule, i.e. through an incision in the capsule, but without involving its attachment to the neck of the bone. When the glenoid is also diseased, mere gouging or scraping the cartilaginous surface will not suffice, but the neck must be thoroughly exposed, so that the whole cup of the glenoid may be removed by powerful forceps.
Cases suitable for Excision.—Cases of chronic disease of the head of the humerus (generally tubercular), or of chronic ulceration of the cartilages which has resisted counter-irritation. Cases of gunshot injury of the joint, or of compound dislocation, or fracture involving the joint. Cases of limited tumours affecting merely the head and upper third of the bone, and non-malignant in character. Anchylosis very rarely requires and would not be much benefited by such an operation.