Fig. 113.—Hydrops of Prepatellar Bursa in a housemaid.Fig. 113.—Hydrops of Prepatellar Bursa in a housemaid.
Fig. 113.—Hydrops of Prepatellar Bursa in a housemaid.
Thetreatmentvaries according to the variety and stage of the affection. In recent cases the symptoms subside under rest and the application of fomentations. Hydrops may be got ridof by blistering, by tapping, or by incision and drainage. When the wall is thickened, the most satisfactory treatment is to excise the bursa; the overlying skin being reflected in the shape of a horse-shoe flap or being removed along with the bursa.
Other Diseases of Bursæare associated withgonorrhœal infection, and withrheumatism, especially that following scarlet fever, and are apt to be persistent or to relapse after apparent cure. In thegoutyform, urate of soda is deposited in the wall of the bursa, and may result in the formation of chalky tumours, sometimes of considerable size (Fig. 114).
Fig. 114.—Section through Bursa over external malleolus, showing deposit of urate of soda. (Cf. Fig. 117.)Fig. 114.—Section through Bursa over external malleolus, showing deposit of urate of soda. (Cf.Fig. 117.)
Fig. 114.—Section through Bursa over external malleolus, showing deposit of urate of soda. (Cf.Fig. 117.)
Tuberculous diseaseof bursæ closely resembles that of tendon sheaths. It may occur as an independent affection, or may be associated with disease in an adjacent bone or joint. It is met with chiefly in the prepatellar and subdeltoid bursæ, or in one of the bursæ over the great trochanter. The clinical features are those of an indolent hydrops, with or without melon-seed bodies, or of uniform thickening of the wall of the bursa; the tuberculous granulation tissue may break down into a cold abscess, and give rise to sinuses. The best treatment is to excise the affected bursa, or, when this is impracticable, to lay it freely open, remove the tuberculous tissue with the sharp spoon or knife, and treat the cavity by the open method.
Syphilitic diseaseis rarely recognised except in the form of bursal and peri-bursal gummata in front of the knee-joint.
New growthsinclude the fibroma, the myxoma, the myeloma or giant-celled tumour, and various forms of sarcoma.
Diseases of Individual Bursæ.—Theolecranon bursais frequentlythe seat of pyogenic infection and of traumatic or trade bursitis, the latter being known as “miner's” or “student's elbow.”
Fig. 115.—Tuberculous Disease of Sub-deltoid Bursa. (From a photograph lent by Sir George T. Beatson.)Fig. 115.—Tuberculous Disease of Sub-deltoid Bursa.(From a photograph lent by Sir George T. Beatson.)
Fig. 115.—Tuberculous Disease of Sub-deltoid Bursa.
(From a photograph lent by Sir George T. Beatson.)
Thesub-deltoidorsub-acromial bursa, which usually presents a single cavity and does not normally communicate with the shoulder-joint, is indispensable in abduction and rotation of the humerus. When the arm is abducted, the fixed lower part or floor of the bursa is carried under the acromion, and the upper part or roof is rolled up in the same direction, hence tenderness over the inflamed bursa may disappear when the arm is abducted (Dawbarn's sign). It is liable to traumatic affections from a fall on the shoulder, pressure, or over-use of the limb. Pain, located commonly at the insertion of the deltoid, is a constant symptom and is especially annoying at night, the patient being unable to get into a comfortable position. Tenderness may be elicited over the anatomical limits of the bursa, and is usually most marked over the great tuberosity, just external to the inter-tubercular (bicipital) groove. When adhesions are present, abduction beyond 10 degrees is impossible. Demonstrable effusion is not uncommon, but is disguised by the overlying tissues. If left to himself, the patient tends to maintain the limb in the “sling position,” and resists movements in the direction of abduction and rotation. In the treatment of this affection the arm should be maintained at a right angle to the body, the arm being rotated medially (Codman).When pain does not prevent it, movements of the arm and massage are persevered with. In neglected cases, when adhesions have formed and the shoulder is fixed, it may be necessary to break down the adhesions under an anæsthetic.
The bursa is also liable to infective conditions, such as acute rheumatism, gonorrhœa, suppuration, or tubercle. In tuberculous disease a large fluctuating swelling may form and acquire the characters of a cold abscess (Fig. 115).
The bursa underneath the tendon of thesubscapularismuscle when inflamed causes alteration in the attitude of the shoulder and impairment of its movements.
An adventitious bursa forms over theacromionprocess in porters and others who carry weights on the shoulder, and may be the seat of traumatic bursitis.
The bursa under thetendon of insertion of the biceps, when the seat of disease, is attended with pain and swelling about a finger's breadth below the bend of the elbow; there is pain and difficulty in effecting the combined movement of flexion and supination, slight limitation of extension, and restriction of pronation.
In the lower extremity, a large number of normal and adventitious bursæ are met with and may be the seat of bursitis. That over thetuberosity of the ischium, when enlarged as a trade disease, is known as “weaver's” or “tailor's bottom.” It may form a fluctuating swelling of great size, projecting on the buttock and extending down the thigh, and causing great inconvenience in sitting (Fig. 116). It sometimes contains a number of loose bodies.
There are two bursæ over thegreat trochanter, one superficial to, the other beneath the aponeurosis of the gluteus maximus; the latter is not infrequently infected by tuberculous disease that has spread from the trochanter.
The bursabetween the psoas muscle and the capsule of the hip-jointmay be the seat of tuberculous disease, and give rise to clinical features not unlike those of disease of the hip-joint. The limb is flexed, abducted and rotated out; there is a swelling in the upper part of Scarpa's triangle, but the movements are not restricted in directions which do not entail putting the ilio-psoas muscle on the stretch.
Cartilaginous and partly ossified loose bodies may accumulate in the ilio-psoas bursa and distend it, both in a downward direction towards the hip-joint, with which it communicates, and upwards, projecting towards the abdomen.
The bursa beneath the quadriceps extensor—subcrural bursa—usually communicates with the knee-joint and shares in its diseases. When shut off from the joint it may suffer independently, and when distended with fluid forms a horse-shoe swelling above the patella.
In front of the patella and its ligament is theprepatellar bursa, which may have one, two, or three compartments, usually communicating with one another. It is the seat of the affection known as “housemaid's knee,” which is very common and is sometimes bilateral, and, less frequently, of tuberculous disease which usually originates in the patella.
Fig. 116.—Great Enlargement of the Ischial Bursa. (Mr. Scot-Skirving's case.)Fig. 116.—Great Enlargement of the Ischial Bursa.(Mr. Scot-Skirving's case.)
Fig. 116.—Great Enlargement of the Ischial Bursa.
(Mr. Scot-Skirving's case.)
The bursabetween the ligamentum patellæ and the tibiais rarely the seat of disease. When it is, there is pain and tenderness referred to the ligament, the patient is unable to extend the limb completely, the tuberosity of the tibia is apparently enlarged, and there is a fluctuating swelling on either side of the ligament, most marked in the extended position of the limb.
Of the numerous bursæ in the popliteal space, thatbetween the semi-membranosus and the medial head of the gastrocnemiusis most frequently the seat of disease, which is usually of the nature of a simple hydrops, forming a fluctuating egg-or sausage-shaped swelling at the medial side of the popliteal space. It is flaccid in the flexed, and tense in the extended position. As a rule it causes little inconvenience, and may be left alone. Otherwise it should be dissected out, and if, as is frequently the case, there is a communication with the knee-joint, this should be closed with sutures.
Fig. 117.—Gouty Disease of Bursæ in a tailor. The bursal tumours were almost entirely composed of urate of soda. (Cf. Fig. 114.)Fig. 117.—Gouty Disease of Bursæ in a tailor. The bursal tumours were almost entirely composed of urate of soda. (Cf.Fig. 114.)
Fig. 117.—Gouty Disease of Bursæ in a tailor. The bursal tumours were almost entirely composed of urate of soda. (Cf.Fig. 114.)
An adventitious bursa may form over thelateral malleolus, especially in tailors, giving rise to the condition known as “tailor's ankle” (Fig. 117).
The bursabetween the tendo-calcaneus (Achillis) and the upper part of the calcaneusmay become inflamed—especially as a result of post-scarlatinal rheumatism or gonorrhœa. The affection is known as Achillo-bursitis. There is severe pain in the region of the insertion of the tendo-calcaneus, the movements at theankle-joint are restricted, and the patient may be unable to walk. There is a tender swelling on either side of the tendon. When, in spite of palliative treatment, the affection persists or relapses, it is best to excise the bursa. The tendo-calcaneus is detached from the calcaneus, the bursa dissected out, and the tendon replaced. If there is a bony projection from the calcaneus, it should be shaved off with the chisel.
The bursa that is sometimes met with on the under aspect of the calcaneus—the subcalcanean bursa—when inflamed, gives rise to pain and tenderness in the sole of the foot. This affection may be associated with a spinous projection from the bone, which is capable of being recognised in a skiagram. The soft parts of the heel are turned forwards as a flap, the bursa is dissected out, and the projection of bone, if present, is removed.
The enlargement of adventitious bursæ over the head of the first metatarsal in hallux valgus; over the tarsus, metatarsus, and digits in the different forms of club-foot; over the angular projection in Pott's disease of the spine; over the end of the bone in amputation stumps, and over hard tumours such as chondroma and osteoma, are described elsewhere.
Surgical Anatomy.—During the period of growth, a long bone such as the tibia consists of a shaft ordiaphysis, and two extremities orepiphyses. So long as growth continues there intervenes between the shaft and each of the epiphyses a disc of actively growing cartilage—the epiphysial cartilage; and at the junction of this cartilage with the shaft is a zone of young, vascular, spongy bone known as themetaphysisorepiphysial junction. The shaft is a cylinder of compact bone enclosing the medullary canal, which is filled with yellow marrow. The extremities, which include the ossifying junctions, consist of spongy bone, the spaces of which are filled with red marrow. The articular aspect of the epiphysis is invested with a thick layer of hyaline cartilage, known as thearticular cartilage, which would appear to be mainly nourished from the synovia.
The external investment—theperiosteum—is thick and vascular during the period of growth, but becomes thin and less vascular when the skeleton has attained maturity. Except where muscles are attached it is easily separated from the bone; at the extremities it is intimately connected with the epiphysial cartilage and with the epiphysis, and at the margin of the latter it becomes continuous with the capsule of the adjacent joint. It consists of two layers, an outer fibrous and an inner cellular layer; the cells, which are called osteoblasts, are continuous with those lining the Haversian canals and the medullary cavity.
The arrangement of theblood vesselsdetermines to some extent the incidence of disease in bone. The nutrient artery, after entering the medullary canal through a special foramen in the cortex, bifurcates, and one main division runs towards each of the extremities, and terminates at the ossifying junction in a series of capillary loops projected against the epiphysial cartilage. This arrangement favours the lodgment of any organisms that may be circulating in the blood, and partly accounts for the frequency with which diseases of bacterial origin develop in the region of the ossifying junction. The diaphysis is also nourished by numerous blood vessels from the periosteum, which penetrate the cortex through the Haversian canals and anastomose with those derived fromthe nutrient artery. The epiphyses are nourished by a separate system of blood vessels, derived from the arteries which supply the adjacent joint. The veins of the marrow are of large calibre and are devoid of valves.
Thenervesenter the marrow along with the arteries, and, being derived from the sympathetic system, are probably chiefly concerned with the innervation of the blood vessels, but they are also capable of transmitting sensory impulses, as pain is a prominent feature of many bone affections.
It has long been believed thatthe function of the periosteumis to form new bone, but this view has been questioned by Sir William Macewen, who maintains that its chief function is to limit the formation of new bone. His experimental observations appear to show that new bone is exclusively formed by the cellular elements or osteoblasts: these are found on the surface of the bone, lining the Haversian canals and in the marrow. We believe that it will avoid confusion in the study of the diseases of bone if the osteoblasts on the surface of the bone are still regarded as forming the deeper layer of the periosteum.
The formation of new bone by the osteoblasts may bedefectiveas a result of physiological conditions, such as old age and disease of a part, and defective formation is often associated with atrophy, or more strictly speaking, absorption, of the existing bone, as is well seen in the edentulous jaw and in the neck of the femur of a person advanced in years. Defective formation associated with atrophy is also illustrated in the bones of the lower limbs of persons who are unable to stand or walk, and in the distal portion of a bone which is the seat of an ununited fracture. The same combination is seen in an exaggerated degree in the bones of limbs that are paralysed; in the case of adults, atrophy of bone predominates; in children and adolescents, defective formation is the more prominent feature, and the affected bones are attenuated, smooth on the surface, and abnormally light.
On the other hand, the formation of new bone may beexaggerated, the osteoblasts being excited to abnormal activity by stimuli of different kinds: for example, the secretion of certain glandular organs, such as the pituitary and thyreoid; the diluted toxins of certain micro-organisms, such as the staphylococcus aureus and the spirochæte of syphilis; a condition of hyperæmia, such as that produced artificially by the application of a Bier's bandage or that which accompanies a chronic leg-ulcer.
The new bone is laid down on the surface, in the Haversian canals, or in the cancellous spaces and medullary canal, or in all three situations. The new bone on the surface sometimes takes the form of a diffuseencrustationof porous or spongy bone as in secondary syphilis, sometimes as a uniform increase in the girth of the bone—hyperostosis, sometimes as a localised heaping up of bone ornode, and sometimes in the form of spicules, spoken of asosteophytes. When the new bone is laid down in the Haversian canals, cancellous spaces and medulla, the bone becomes denser and heavier, and is said to besclerosed; in extreme instances this may result in obliteration of the medullary canal. Hyperostosis and sclerosis are frequently met with in combination, a condition that is well illustrated in the femur and tibia in tertiary syphilis; if the subject of this condition is confined to bed for several months before his death, the sclerosis may be undone, and rarefaction may even proceed beyond the normal, the bone becoming lighter and richer in fat, although retaining its abnormal girth.
Thefunction of the epiphysial cartilageis to provide for the growth ofthe shaft in length. While all epiphysial cartilages contribute to this result, certain of them functionate more actively and for a longer period than others. Those at the knee, for example, contribute more to the length of limb than do those at the hip or ankle, and they are also the last to unite. In the upper limb the more active epiphyses are at the shoulder and wrist, and these also are the last to unite.
The activity of the epiphysial cartilage may be modified as a result of disease. In rickets, for example, the formation of new bone may take place unequally, and may go on more rapidly in one half of the disc than in the other, with the result that the axis of the shaft comes to deviate from the normal, giving rise to knock-knee or bow-knee. In bacterial diseases originating in the marrow, if the epiphysial junction is directly involved in the destructive process, its bone-forming functions may be retarded or abolished, and the subsequent growth of the bone be seriously interfered with. On the other hand, if it is not directly involved but is merely influenced by the proximity of an infective focus, its bone-forming functions may be stimulated by the diluted toxins and the growth of the bone in length exaggerated. In paralysed limbs the growth from the epiphyses is usually little short of the normal. The result of interference with growth is more injurious in the lower than in the upper limb, because, from the functional point of view, it is essential that the lower extremities should be approximately of equal length. In the forearm or leg, where there are two parallel bones, if the growth of one is arrested the continued growth of the other results in a deviation of the hand or foot to one side.
In certain diseases, such as rickets and inherited syphilis, and in developmental anomalies such as achondroplasia,dwarfingof the skeleton results from defective growth of bone at the ossifying junctions. Conversely, excessive growth of bone at the ossifying junctions results in abnormal height of the skeleton orgiantismas a result, for example, of increased activity of the pituitary in adolescents, and in eunuchs who have been castrated in childhood or adolescence; in the latter, union of the epiphyses at the ends of the long bones is delayed beyond the usual period at which the skeleton attains maturity.
Regeneration of Bone.—When bone has been lost or destroyed as a result of injury or disease, it is capable of being reproduced, the extent to which regeneration takes place varying under different conditions. The chief part in the regeneration of bone is played by the osteoblasts in the adjacent marrow and in the deeper layer of the periosteum. The shaft of a long bone may be reproduced after having been destroyed by disease or removed by operation. The flat bones of the skull and the bones of the face, which are primarily developed in membrane, have little capacity of regeneration; hence, when bone has been lost or removed in these situations, there results a permanent defect.
Wounds or defects in articular cartilage are repaired by fibrous or osseous tissue derived from the subjacent cancellous spaces.
Transplantation of Bone—Bone-grafting.—Clinical experience is conclusive that a portion of bone which has been completely detached from its surroundings—for example, a trephine circle, or a flap of bone detached with the saw, or the loose fragments in a compound fracture—may become, if replaced in position, firmly and permanently incorporated with the surrounding bone. Embedded foreign bodies, on the other hand, such as ivory pegs or decalcified bone, exhibit, on removal after a sufficient interval, evidence of having been eroded, in the shape of worm-eaten depressions and perforations, and do not become united or fused to thesurrounding bone. It follows from this that the implanting of living bone is to be preferred to the implanting of dead bone or of foreign material. We believe that transplanted living bone when placed under favourable conditions survives and becomes incorporated with the bone with which it is in contact, and does not merely act as a scaffolding. We believe also that the retention of the periosteum on the graft is not essential, but, by favouring the establishment of vascular connections, it contributes to the survival of the graft and the success of the transplantation. Macewen maintains that bone grafts “take” better if broken up into small fragments; we regard this as unnecessary. Bone grafts yield better functional results when they are immovably fixed to the adjacent bone by suture, pegs, or plates. As in all grafting procedures, asepsis is essential.
Transplanted bone retains its vitality when embedded in the soft parts, but is gradually absorbed and replaced by fibrous tissue.
The morbid processes met with in bone originate in the same way and lead to the same results as do similar processes in other tissues. The structural peculiarities of bone, however, and the important changes which take place in the skeleton during the period of growth, modify certain of the clinical and pathological features.
Definition of Terms.—Any diseased process that affects the periosteum is spoken of asperiostitis; the termosteomyelitisis employed when it is located in the marrow. The termepiphysitishas been applied to an inflammatory process in two distinct situations—namely, the ossifying nucleus in the epiphysis, and the ossifying junction or metaphysis between the epiphysial cartilage and the diaphysis. We shall restrict the term to inflammation in the first of these situations. Inflammation at the ossifying junction is included under the term osteomyelitis.
The termrarefying ostitisis applied to any process that is attended with excessive absorption of the framework of a bone, whereby it becomes more porous or spongy than it was before, a condition known asosteoporosis.
The termcariesis employed to indicate any diseased process associated with crumbling away of the trabecular framework of a bone. It may be considered as the equivalent of ulceration or molecular destruction in the soft parts. The carious process is preceded by the formation of granulation tissue in the marrow or periosteum, which eats away and replaces the bone in contact with it. The subsequent degeneration and death of the granulation tissue under the necrotic influence of bacterial toxins results in disintegration and crumbling away of the trabecular framework of the portion of bone affected. Clinically, carious boneyields a soft grating sensation under the pressure of the probe. The macerated bone presents a rough, eroded surface.
The termdry caries(caries sicca) is applied to that variety which is unattended with suppuration.
Necrosisis the term applied to the death of a tangible portion of bone, and the dead portion when separated is called asequestrum. The termexfoliationis sometimes employed to indicate the separation or throwing off of a superficial sequestrum. The edges and deep surface of the sequestrum present a serrated or worm-eaten appearance due to the process of erosion by which the dead bone has been separated from the living.
The most important diseases in this group are the pyogenic, the tuberculous, and the syphilitic.
Pyogenic Diseases of Bone.—These diseases result from infection with pyogenic organisms, and two varieties or types are recognised according to whether the organisms concerned reach their seat of action by way of the blood-stream, or through an infection of the soft parts in contact with the bone.
Diseases caused by the Staphylococcus Aureus.—As the majority of pyogenic diseases are due to infection with the staphylococcus aureus, these will be described first.
Acute osteomyelitisis a suppurative process beginning in the marrow and tending to spread to the periosteum. The disease is common in children, but is rare after the skeleton has attained maturity. Boys are affected more often than girls, in the proportion of three to one, probably because they are more liable to exposure, to injury, and to violent exertion.
Etiology.—Staphylococci gain access to the blood-stream in various ways, it may be through the skin or through a mucous surface.
Such conditions as, for example, a blow, some extra exertion such as a long walk, or exposure to cold, as in wading, may act as localising factors.
The long bones are chiefly affected, and the commonest sites are: either end of the tibia and the lower end of the femur; the other bones of the skeleton are affected in rare instances.
Pathology.—The disease commences and is most intense in the marrow of the ossifying junction at one end of the diaphysis;it may commence at both ends simultaneously—bipolar osteomyelitis; or, commencing at one end, may spread to the other.
The changes observed are those of intense engorgement of the marrow, going on to greenish-yellow purulent infiltration. Where the process is most advanced—that is, at the ossifying junction—there are evidences of absorption of the framework of the bone; the marrow spaces and Haversian canals undergo enlargement and become filled with greenish-yellow pus. This rarefaction of the spongy bone is the earliest change seen with the X-rays.
The process may remain localised to the ossifying junction, but usually spreads along the medullary canal for a varying distance, and also extends to the periosteum by way of the enlarged Haversian canals. The pus accumulates under the periosteum and lifts it up from the bone. The extent of spread in the medullary canal and beneath the periosteum is in close correspondence. The periosteum of the diaphysis is easily separated—hence the facility with which the pus spreads along the shaft; but in the region of the ossifying junction it is raised with difficulty because of its intimate connection with the epiphysial cartilage. Less frequently there is more than one collection of pus under the periosteum, each being derived from a focus of suppuration in the subjacent marrow. The pus perforates the periosteum, and makes its way to the surface by the easiest anatomical route, and discharges externally, forming one or more sinuses through which fresh infection may take place. The infection may spread to the adjacent joint, either directly through the epiphysis and articular cartilage, or along the deep layer of the periosteum and its continuation—the capsular ligament. When the epiphysis is intra-articular, as, for example, in the head of the femur, the pus when it reaches the surface of the bone necessarily erupts directly into the joint.
While the occurrence of purely periosteal suppuration is regarded as possible, we are of opinion that the embolic form of staphylococcal osteomyelitis always originates in the marrow.
The portion of the diaphysis which has sustained the action of the concentrated toxins has its vitality further impaired as a result of the stripping of the periosteum and thrombosis of the blood vessels of the marrow, so thatnecrosisof bone is one of the most striking results of the disease, and as this takes place rapidly, that is, in a day or two, the termacute necrosis, formerly applied to the disease, was amply justified.
When there is marked rarefaction of the bone at the ossifyingjunction, the epiphysis is liable to be separated—epiphysiolysis. The separation usually takes place through the young bone of the ossifying junction, and the surfaces of the diaphysis and epiphysis are opposed to each other by irregular eroded surfaces bathed in pus. The separated epiphysis may be kept in place by the periosteum, but when this has been detached by the formation of pus beneath it, the epiphysis is liable to be displaced by muscular action or by some movement of the limb, or it is the diaphysis that is displaced, for example, the lower end of the diaphysis of the femur may be projected into the popliteal space.
The epiphysial cartilage usually continues its bone-forming functions, but when it has been seriously damaged or displaced, the further growth of the bone in length may be interfered with. Sometimes the separated and displaced epiphysis dies and constitutes a sequestrum.
The adjacent joint may become filled at an early stage with a serous effusion, which may be sterile. When the cocci gain access to the joint, the lesion assumes the characters of a purulent arthritis, which, from its frequency during the earlier years of life, has been calledthe acute arthritis of infants.
Separation of an epiphysis nearly always results in infection and destruction of the adjacent joint.
Osteomyelitis is rare in the bones of the carpus and tarsus, and the associated joints are usually infected from the outset. In flat bones, such as the skull, the scapula, or the ilium, suppuration usually occurs on both aspects of the bone as well as in the marrow.
Clinical Features.—The constitutional symptoms, which are due to the associated toxæmia, vary considerably in different cases. In mild cases they may be so slight as to escape recognition. In exceptionally severe cases the patient may succumb before there are obvious signs of the localisation of the staphylococci in the bone marrow. In average cases the temperature rises rapidly with a rigor and runs an irregular course with morning remissions, there is marked general illness accompanied by headache, vomiting, and sometimes delirium.
The local manifestations are pain and tenderness in relation to one of the long bones; the pain may be so severe as to prevent sleep and to cause the child to cry out. Tenderness on pressure over the bone is the most valuable diagnostic sign. At a later stage there is an ill-defined swelling in the region of the ossifying junction, with œdema of the overlying skin and dilatation of the superficial veins.
The swelling appears earlier and is more definite in superficial bones such as the tibia, than in those more deeply placed such as the upper end of the femur. It may be less evident to the eye than to the fingers, and is best appreciated by gently stroking the bone from the middle of its shaft towards the end. The maximum thickening and tenderness usually correspond to the junction of the diaphysis with the epiphysis, and the swelling tails off gradually along the shaft. As time goes on there is redness of the skin, especially over a superficial bone, such as the tibia, the swelling becomes softer, and gives evidence of fluctuation. This stage may be reached at the end of twenty-four hours, or not for some days.
Suppuration spreads towards the surface, until, some days later, the skin sloughs and pus escapes, after which the fever usually remits and the pain and other symptoms are relieved. The pus may contain blood and droplets of fat derived from the marrow, and in some cases minute particles of bone are present also. The presence of fat and bony particles in the pus confirms the medullary origin of the suppuration.
If an incision is made, the periosteum is found to be raised from the bone; the extent of the bare bone will be found to correspond fairly accurately with the extent of the lesion in the marrow.
Local Complications.—The adjacent joint may exhibit symptoms which vary from those of a simple effusion to those of a purulentarthritis. The joint symptoms may count for little in the clinical picture, or, as in the case of the hip, may so predominate as to overshadow those of the bone lesion from which they originated.
Separation and displacement of the epiphysisusually reveals itself by an alteration in the attitude of the limb; it is nearly always associated with suppuration in the adjacent joint.
Whenpathological fractureof the shaft occurs, as it may do, from some muscular effort or strain, it is attended with the usual signs of fracture.
Dislocationof the adjacent joint has been chiefly observed at the hip; it may result from effusion into the joint and stretching of the ligaments, or may be the sequel of a purulent arthritis; the signs of dislocation are not so obvious as might be expected, but it is attended with an alteration in the attitude of the limb, and the displacement of the head of the bone is readily shown in a skiagram.
General Complications.—In some cases amultiplicity of lesionsin the bones and joints imparts to the disease thefeatures of pyæmia. The occurrence of endocarditis, as indicated by alterations in the heart sounds and the development of murmurs, may cause widespread infective embolism, and metastatic suppurations in the kidneys, heart-wall, and lungs, as well as in other bones and joints than those primarily affected. The secondary suppurations are liable to be overlooked unless sought for, as they are rarely attended with much pain.
In these multiple forms of osteomyelitis the toxæmic symptoms predominate; the patient is dull and listless, or he may be restless and talkative, or actually delirious. The tongue is dry and coated, the lips and teeth are covered with sordes, the motions are loose and offensive, and may be passed involuntarily. The temperature is remittent and irregular, the pulse small and rapid, and the urine may contain blood and albumen. Sometimes the skin shows erythematous and purpuric rashes, and the patient may cry out as in meningitis. The post-mortem appearances are those of pyæmia.
Differential Diagnosis.—Acute osteomyelitis is to be diagnosed from infections of the soft parts, such as erysipelas and cellulitis, and, in the case of the tibia, from erythema nodosum. Tenderness localised to the ossifying junction is the most valuable diagnostic sign of osteomyelitis.
When there is early and pronounced general intoxication, there is likely to be confusion with other acute febrile illnesses, such as scarlet fever. In all febrile conditions in children and adolescents, the ossifying junctions of the long bones should be examined for areas of pain and tenderness.
Osteomyelitis has many features in common with acute articular rheumatism, and some authorities believe them to be different forms of the same disease (Kocher). In acute rheumatism, however, the joint symptoms predominate, there is an absence of suppuration, and the pains and temperature yield to salicylates.
Theprognosisvaries with the type of the disease, with its location—the vertebræ, skull, pelvis, and lower jaw being specially unfavourable—with the multiplicity of the lesions, and with the development of endocarditis and internal metastases.
Treatment.—This is carried out on the same lines as in other pyogenic infections.
In the earliest stages of the disease, the induction of hyperæmia is indicated, and should be employed until the diagnosis is definitely established, and in the meantime preparations for operation should be made. An incision is made down to and through the periosteum, and whether pus is found ornot, the bone should be opened in the vicinity of the ossifying junction by means of a drill, gouge, or trephine. If pus is found, the opening in the bone is extended along the shaft as far as the periosteum has been separated, and the infected marrow is removed with the spoon. The cavity is then lightly packed with rubber dam, or, as recommended by Bier, the skin edges are brought together by sutures which are loosely tied to afford sufficient space between them for the exit of discharge, and the hyperæmic treatment is continued.
When there is widespread suppuration in the marrow, and the shaft is extensively bared of periosteum and appears likely to die, it may be resected straight away or after an interval of a day or two. Early resection of the shaft is also indicated if the opening of the medullary canal is not followed by relief of symptoms. In the leg and forearm, the unaffected bone maintains the length and contour of the limb; in the case of the femur and humerus, extension with weight and pulley along with some form of moulded gutter splint is employed with a similar object.
Amputation of the limb is reserved for grave cases, in which life is endangered by toxæmia, which is attributed to the primary lesion. It may be called for later if the limb is likely to be useless, as, for example, when the whole shaft of the bone is dead without the formation of a new case, when the epiphyses are separated and displaced, and the joints are disorganised.
Flat bones, such as the skull or ilium, must be trephined and the pus cleared out from both aspects of the bone. In the vertebræ, operative interference is usually restricted to opening and draining the associated abscess.
Nature's Effort at Repair.—In cases which are left to nature, and in which necrosis of bone has occurred, those portions of the periosteum and marrow which have retained their vitality resume their osteogenetic functions, often to an exaggerated degree. Where the periosteum has been lifted up by an accumulation of pus, or is in contact with bone that is dead, it proceeds to form new bone with great activity, so that the dead shaft becomes surrounded by a sheath or case of new bone, known as theinvolucrum(Fig. 118). Where the periosteum has been perforated by pus making its way to the surface, there are defects or holes in the involucrum, calledcloacæ. As these correspond more or less in position to the sinuses in the skin, in passing a probe down one of the sinuses it usually passes through a cloaca and strikes the dead bone lying in the interior. If the periosteum has beenextensively destroyed, new bone may only be formed in patches, or not at all. The dead bone is separated from the living by the agency of granulation tissue with its usual complements of phagocytes and osteoclasts, so that the sequestrum presents along its margins and on its deep surface a pitted, grooved, and worm-eaten appearance, except on the periosteal aspect, which is unaltered. Ultimately the dead bone becomes loose and lies in a cavity a little larger than itself; the wall of the cavity is formed by the new case, lined with granulation tissue. The separation of the sequestrum takes place more rapidly in the spongy bone of the ossifying junction than in the compact bone of the shaft.
Fig. 118.—Shaft of Femur after Acute Osteomyelitis. The shaft has undergone extensive necrosis, and a shell of new bone has been formed by the periosteum.Fig. 118.—Shaft of Femur after Acute Osteomyelitis. The shaft has undergone extensive necrosis, and a shell of new bone has been formed by the periosteum.
Fig. 118.—Shaft of Femur after Acute Osteomyelitis. The shaft has undergone extensive necrosis, and a shell of new bone has been formed by the periosteum.
When foci of suppuration have been scattered up and down the medullary cavity, and the bone has died in patches, several sequestra may be included by the new case; each portion of dead bone is slowly separated, and comes to lie in a cavity lined by granulations.
Even at a distance from the actual necrosis there is formation of new bone by the marrow; the medullary canal is often obliterated, and the bone becomes heavier and denser—sclerosis; and the new bone which is deposited on the original shaft results in an increase in the girth of the bone—hyperostosis.
Pathological fractureof the shaft may occur at the site ofnecrosis, when the new case is incapable of resisting the strain put upon it, and is most frequently met with in the shaft of the femur. Short of fracture, there may be bending or curving of the new case, and this results in deformity and shortening of the limb (Fig. 119).
Theextrusion of a sequestrummay occur, provided there is a cloaca large enough to allow of its escape, but the surgeon has usually to interfere by performing the operation of sequestrectomy. Displacement or partial extrusion of the dead bone may cause complications, as when a sequestrum derived from the trigone of the femur perforates the popliteal artery or the cavity of the knee-joint, or a sequestrum of the pelvis perforates the wall of the urinary bladder.
The extent to which bone which has been lost is reproduced varies in different parts of the skeleton: while the long bones, the scapula, the mandible, and other bones which are developed in cartilage are almost completely re-formed, bones which are entirely developed in membrane, such as the flat bones of the skull and the maxilla, are not reproduced.
It may be instructive to describethe X-ray appearances of a long bone that has passed through an attack of acute osteomyelitissevere enough to have caused necrosis of part of the diaphysis. The shadow of the dead bone is seen in the position of the original shaft which it represents; it is of the same shape and density as the original shaft, while its margins present an irregular contour from the erosion concerned in its separation. The sequestrum is separated from the living bone by a clearzone which corresponds to the layer of granulations lining the cavity in which it lies. This clear zone separating the shadow of the dead bone from that of the living bone by which it is surrounded is conclusive evidence of a sequestrum. The medullary canal in the vicinity of the sequestrum being obliterated, is represented by a shadow of varying density, continuous with that of the surrounding bone. The shadow of the new case or involucrum with its wavy contour is also in evidence, with its openings or cloacæ, and is mainly responsible for the increase in the diameter of the bone.
The skiagram may also show separation and displacement of the adjacent epiphysis and destruction of the articular surfaces or dislocation of the joint.
Sequelæ of Acute Suppurative Osteomyelitis.—The commonest sequel is the presence of a sequestrum with one or more discharging sinuses; owing to the abundant formation of scar tissue these sinuses have rigid edges which are usually depressed and adherent to the bone.