In many cases the extent of the operation can only be decided after exploration.  The aim is to remove all the disease with the least impairment of function and the minimum sacrifice of healthy tissue.  The more open the method of operating the better, so that all parts of the joint may be available for inspection.  The methods of Kocher, which permit of dislocating the joint, are specially to be recommended, as this procedure affords the freest possible access.  Diseased synovial membrane is removed with the scissors or knife.  If the cartilages are sound, and if a movable joint is aimed at, they may be left; but if ankylosis is desired, they must be removed.  Localised disease of the cartilage should be removed with the spoon or gouge, and the bone beneath investigated.  If the articular surface is extensively diseased, a thin slice of bone should be removed, and if foci in the marrow are then revealed, it is better to gouge them out than to remove further slices of bone, as this involves sacrifice of the cortex and periosteum.

Operative treatment of deformities resulting from tuberculous joint disease has almost entirely replaced reduction by force; the contracted soft parts are divided, and the bone is resected.

Amputation for tuberculous joint disease has become one of the rare operations of surgery, and is only justified when less radical measures have failed and the condition of the limb is affecting the general health.  Amputation is more frequently called for in persons past middle life who are the subjects of pulmonary tuberculosis.

SYPHILITIC DISEASE

Syphilitic affections of joints are comparatively rare.  As in tuberculosis, the disease may be first located in the synovial membrane, or it may spread to the joint from one of the bones.

In #acquired syphilis#, at an early stage and before the skin eruptions appear, one of the large joints, such as the shoulder or knee, may be the seat of pain—­arthralgia—­which is worse at night.  In the secondary stage, a synovitis with serous effusion is not uncommon, and may affect several joints.  Syphilitic hydrops is met with almost exclusively in the knee; it is frequently bilateral, and is insidious in its onset and progress, the patient usually being able to go about.

In the tertiary stage the joint lesions are persistent and destructive, and result from the formation of gummata, either in the deeper layers of the synovial membrane or in the adjacent bone or periosteum.

Peri-synovial and peri-bursal gummata are met with in relation to the knee-joint of middle-aged adults, especially women.  They are usually multiple, develop slowly, and are rarely sensitive or painful.  One or more of the gummata may break down and give rise to tertiary ulcers.  The co-existence of indolent swellings, ulcers, and depressed scars in the vicinity of the knee is characteristic of tertiary syphilis.