BONES, DISEASES AND INJURIES OF. The more specific diseases affecting the bones of the human body are treated under separate headings (see TUBERCULOSIS; VENEREAL DIS EASES, etc.) ; in this article injuries, inflammations and tumours of bone are dealt with.
There are two kinds of bone, the compact, which is dense and hard and forms the shafts of the long bones of the limbs and fingers, and the cancellous, which is bone of a more open, spongy structure, and forms the ends of the long bones and the whole of such bones as the vertebrae and those of similar shape. Every bone is closely invested by a thin, fibrous sheath—the periosteum —which adheres closely to it and affords attachment for muscle and tendons. It also plays a part in the production of new bone, not only during the period of growth but also in conditions of injury and disease. A typical long bone consists of a shaft com posed of compact bone and of two articular ends formed of can cellous bone, the line of union between them being known as the epiphyseal line, which is a narrow zone of actively-growing bone cells. It is here that growth in the length of the bone occurs until adult life is reached, when the epiphysis disappears and no further increase in length is possible. Injury or disease of the epiphyseal line may result in cessation of growth forthwith, or in certain rare cases it may produce excessive growth with the re sult that the affected limb becomes longer than its fellow. In rickets (q.v.) the epiphyseal line becomes widened and very ir regular, thus producing the characteristic changes at the wrist and in the ribs. The shaft of a long bone is hollow and is filled with marrow, a fatty tissue possessing numerous blood vessels which branch in all directions and enter the bone through tiny channels for the purpose of supplying it with nourishment.
Fractures (q.v.) constitute by far the largest proportion of in juries to bone. In the aged the bones become more brittle and break as the result of a degree of violence which in earlier life might almost pass unnoticed. In the very young the opposite condition obtains, for the bones are relatively soft and the frac ture may be of the Greenstick variety, in which the bone bends instead of breaking completely through.
There is a rare disease known as fragilitas ossium, in which for some unknown reason the bones are unduly fragile, and fractures repeatedly follow trivial injuries.
Fractures are also described as being simple and compound. A simple, or, as it is now usually called, a closed fracture, is one where the overlying skin is not injured, or at least not injured in such a way as to establish communication between the broken bone and the external air. A fracture is described as compound, or open, when the overlying skin is damaged in such a way as to expose the injured bone to the danger of infection by microbes gaining entrance from the outside air through the broken skin.
The detection of a fracture depends upon intelligent apprecia tion of the symptoms following the injury. These may be very obvious, for the limb may be grossly deformed and shortened by overlapping of the fragments, and on examination a grating feeling may be elicited—crepitus—when the broken ends are moved. But in some cases the swelling of the soft parts is so great that it is difficult for the medical attendant to determine whether a fracture is present or not. It is in these cases that X-rays have developed one of their greatest uses in medicine, and it is an al most universal custom to have an X-ray photograph taken in all cases of injury to bone.
Treatment of Fractures.—As soon as the presence of a frac ture is detected it is essential to get the broken ends into close apposition with one another by one of the numerous means available. It may be possible to effect this by ordinary manipu lation, with or without an anaesthetic, but in many cases this proves impossible and more radical measures have to be aaopted. An operation is then undertaken on the following general lines.
The site of the fracture is exposed by an incision through the overlying soft parts and the fractured ends of the bone are brought into close contact with one another; they are then held in position temporarily by means of special bone forceps. It is then necessary to decide what particular method shall be utilized for the purpose of obtaining permanent fixation. A complicated fracture in a large bone like the thigh bone affords plenty of scope for the ingenuity of the surgeon. He may decide to fix the broken ends together with wire of silver, or some similar mate rial of sufficient tensile strength to bear the strain, and sufficiently soft to admit of easy manipulation; but in all probability, with so large and strong a bone to deal with, he will not pin his faith on wire but will adopt the more difficult but more certain method of plating.
Plating consists in bridging the fracture with a narrow steel plate from three to six inches in length which is fixed by several screws to the uninjured bone above and below the fracture. This method of fixation of fractures with wire or metal plates has the disadvantage that the foreign body necessarily left in the limb may subsequently give rise to trouble and have to be removed. This difficulty has led to the development of still another method by means of plates fashioned from beef-bone and fixed by beef bone screws or pegs. These are carefully prepared from the leg bones of the ox, are sterilized by boiling, and have this great ad vantage, that after their work is done they are slowly absorbed by the tissues and in time completely disappear.
Operations of this character are serious undertakings only em barked upon after careful consideration of all the factors in the case, and after failure to adjust and maintain the bone in position by simpler means. They are not of course confined to the treat ment of recent fractures, but are also applicable to old-standing cases of non-union or mal-union which have resulted from inef fective or inefficient treatment. Such non-union or mal-union fre quently arises from causes outside the control of the medical attendant, as for example in cases of compound fracture result ing from gunshot wounds or other causes, where injury to the soft parts precludes successful and immediate treatment of the frac ture itself.
Inflammations o f bone fall into two categories, the acute and the chronic. The acute forms include the simple and evanescent conditions resulting from slight injuries, but they also include the disease known as acute osteomyelitis, the most violent and the most serious inflammatory condition of bone. Generally speak ing, it is a disease of young people and is due to infection of the interior of the bone by staphylococcus pyogenes aureus the same microbe that causes boils and carbuncles; indeed, this disease might in a sense be well described as a carbuncle of bone. Owing to the confined space available, the pus resulting from the inflammation is formed under so much pressure that great pain, high temperature and great constitutional disturbance soon manifest themselves. The pus rapidly makes its way up and down the marrow cavity and also outwards through the bone, and so collects under the periosteum which it strips from the bone, thus depriving it of some of its blood supply. The simulta neous destruction of blood vessels in the marrow by the pressure of pus may be so complete as totally to deprive the affected part of the bone of its essential blood supply and cause its death, or necro sis, the dead portion of bone subsequently becoming separated from the living and forming a sequestrum. Since this disease nearly always affects the bone near a joint it is often mistaken at its onset and treated for acute rheumatism, even by skilled observ ers. This is a serious matter, for osteomyelitis is so grave a disease and is so apt to be complicated by general blood-poisoning (septi caemia) that delay in its detection may cost the limb or even the life of the patient. The appropriate treatment is immediate inci sion over the affected area, the evacuation of the pus found under the periosteum, and the opening up of the marrow cavity in order to permit of free escape of the poisonous products from the interior of the bone. But no matter how prompt and how successful the treatment may be, recovery is slow and healing long delayed.
Chronic inflammations of bone may be produced by a variety of infective agents, including the organisms of syphilis and ty phoid, but by far the most common and most important is the tuberculosis bacillus which especially selects the cancellous ends of the long bones or such cancellous bones as the vertebrae for its attacks, producing the slow destructive effect known as tu berculous caries. The treatment of this disease has fortunately undergone a revolution in recent years, for the drastic and crip pling operations formerly in use are now replaced by a regime which includes complete rest of the affected part and, very lim ited and conservative surgical operations for the purpose of evac uating abscesses, combined with sunlight treatment, real or arti ficial. When persevered with, such methods almost always effect a cure in every case. Prof. Rollier of Leysin has been a pioneer in the development of this line of attack upon the tuberculosis of bone, and great success has been obtained at his clinic in the Swiss mountains. Similar methods of treatment have been proved to be possible in our English climate, and at the Treloar Home for Cripples at Alton a high degree of success has been obtained.
Tumours, or new growths of bone are comparatively rare dis eases: Of the simple or non-malignant new growths of bone the only one of real importance is the cyst, which develops in the long bones of young people and grows so slowly and imperceptibly that its presence may be entirely unsuspected until the bone be comes so weakened that it is fractured by some trivial injury. Treatment consists in opening the cyst and scraping out the lin ing membrane, the resulting cavity being filled with a graft of healthy bone taken from the patient's shin. In a few recent cases a graft of fatty tissue taken from the abdominal wall has proved successful.
Malignant tumours (see TUMOURS) may arise primarily in bones, and are then known as sarcomas. There are two main varieties of sarcoma affecting bones, the endosteal or myeloid, and the periosteal. The former arises almost always within the articular ends of the long bones and forms a tumour of very pe culiar character. It slowly expands the bone in which it arises and destroys its interior, so that in due course a large swelling is produced which consists of the tumour itself, covered by a layer of bone so thin that the mere pressure of the examining finger gives rise to the sensation known as egg-shell crackling, and may, indeed, fracture it.
The malignancy of endosteal growths is rather limited, for although if untreated they go on growing indefinitely, and may destroy life by their local effects, they do not give rise to second ary growths. in other parts of the body, and in consequence are often spoken of as semi-malignant. They are healed by complete removal of the part of the bone in which they originate, though this often means the sacrifice of the affected limb.
When dealing with periosteal sarcoma we are faced with an entirely different set of circumstances. As its name implies it grows from the outer surface of the bone, generally a long bone of the lower limb, and it is malignant in the highest possible de gree. The most usual treatment is amputation of the affected limb, but even then the disease is apt to return in the stump or else in the form of secondary deposits in the lungs. On the whole periosteal sarcoma is a terribly fatal disease, for no matter how prompt and how radical the treatment may be, the percentage of cases that may be regarded as cured is smaller than in almost every other kind of malignant growth.
Cancer or carcinoma cannot originate in bone, but does occur with some frequency as a secondary phenomenon during the course of such disease as cancer of the breast, prostate, thyroid and kidney. Small fragments of the original growth become de tached and are distributed by the blood or lymph to the bones of the arms or thighs or spine. A characteristic of this condition, owing to the replacement of healthy bone by cancer tissue, is the occurrence of so-called spontaneous fractures, i.e., fractures resulting from the muscular strain of ordinary movements. When this stage in the course of a cancer case is reached, the patient is ' beyond the help of medicine and surgery, and nothing can be done, in our present state of knowledge, beyond measures di rected to the relief of pain.