These changes are necessarily a.s.sociated with restriction of movement, and in advanced cases with striking deformity, which consists in shortening of the limb, usually with eversion and displacement of the trochanter upwards and backwards in relation to Nelaton"s line.
The _clinical features_ are usually so characteristic that there is little difficulty in diagnosis. Restriction of the movements of abduction and adduction, the presence of cracking and of grating of the articular surfaces, and the aggravation of the pain and stiffness after resting the limb, are characteristic of arthritis deformans. The prominence of sciatic pain may lead to the disease being regarded as sciatica.
The greatest difficulty is met with in cases in which the disease occurs as mon-articular affection in adolescents, for the resemblance to tuberculous disease of the hip and to c.o.xa vara may be close.
Skiagrams do not always enable one to differentiate between them.
_Treatment_ is conducted on the same lines as in other joints. The normal movements are maintained by suitable exercises, and an effort is made to diminish the pressure on the articular surfaces in walking by the use of sticks or crutches.
Shortening of the limb may be compensated by raising the sole of the boot. When the X-rays show that the disability is mainly due to new bone locking the head of the femur, such new bone may be removed by operation, _cheilotomy_ (Sampson Handley). Excision of the joint has in some cases yielded satisfactory results; it is indicated in young patients who are otherwise healthy, and who are unable to walk on account of pain and deformity.
#Osteo-chondritis Deformans Juvenilis.#--Under this term Perthes describes an affection of the hip in children which differs in many respects from the juvenile form of arthritis deformans. Islands of cartilage appear in the epiphysis of the head of the femur, and the epiphysis itself becomes flattened without involvement of the articular surface or of the acetabulum.
The disease is met with in children between five and ten; there is a limp in walking without pain or sensitiveness, so that the child continues to take part in games. Abduction is markedly restricted and the trochanter is elevated and prominent. There is no crepitation on movement or other signs of involvement of the articular surfaces. The X-rays show the deformity of the head and clear areas in the interior of the upper epiphysis corresponding to the islands of cartilage; these clear areas resemble those due to caseous foci in tuberculous c.o.xitis.
The disease runs a chronic course, and in the course of a year or two the limp and the restriction of abduction disappear, so that no active treatment is called for.
#Neuro-Arthropathies.#--_Charcot"s disease_ is usually met with in men over thirty who suffer from tabes dorsalis. One or both hip-joints may be affected. Sometimes the first manifestation is a hydrops and a fluctuating swelling in the upper part of Scarpa"s triangle. In many of the recorded cases, however, attention has first been directed to the disease by the deformity and limp a.s.sociated with disappearance of the head of the femur, or by the occurrence of pathological dislocation. The absence of pain and tenderness is characteristic.
When dislocation has occurred, the limb is short, and the upper end of the femur is freely movable on the dorsum ilii. When both hips are dislocated, the att.i.tude and gait are similar to those observed in bilateral congenital dislocation. The rotation arc of the great trochanter may be much reduced as a result of the disappearance of the head of the femur. There may be considerable formation of new bone, giving rise to large tumour-like ma.s.ses in relation to the capsular ligament and the muscles surrounding the joint.
The _treatment_ consists in protecting and supporting the joint. When the affection is unilateral, advantage may be derived from a Thomas"
or other form of splint, along with a patten and crutches; in bilateral cases, from the use of crutches alone.
_Loose bodies in the hip_ are mostly the result of hypertrophy of synovial fringes in arthritis deformans and in Charcot"s disease, and do not figure in the clinical features of these affections; Caird has observed a case in which the cavity of the joint and the bursa beneath the psoas were filled with loose bodies, many of which had undergone ossification and gave a characteristic picture with the X-rays.
_Hysterical affections_ of the hip resemble those in other joints.
THE KNEE-JOINT
The knee is more often the seat of disease than any other joint in the body.
The synovial membrane extends beneath the quadriceps extensor as a cul-de-sac, which either communicates with the sub-crural bursa, or forms with it one continuous cavity. When the joint is distended with fluid, this upper pouch bulges above and on either side of the patella, and this bone is "floated" off the condyles of the femur.
When there is only a small amount of fluid, it is most easily recognised while the patient stands with his feet together and the trunk bent forwards at the hip-joints, and the quadriceps completely relaxed; the fluid then bulges above and on each side of the patella, and its presence is readily detected, especially on comparison with the joint of the other side.
On account of the great extent of the synovial membrane, a large quant.i.ty of serous effusion may acc.u.mulate in the joint in a comparatively short time, as a result either of injury or disease. The villous processes and fringes may take on an exaggerated growth, and give rise to pedunculated and other forms of loose body.
The bursae in the popliteal s.p.a.ce, especially that between the semi-membranosus and the medial head of the gastrocnemius, as well as the sub-crural bursa, frequently communicate with the synovial cavity of the knee and may share in its diseases.
As the epiphyses at the knee are mainly responsible for the growth in length of the lower extremity, and are late in uniting with their respective shafts--twenty-one to twenty-five years--serious shortening of the limb may result if their functions are interfered with, whether by disease or injury. The epiphysial cartilages lie beyond the limits of the synovial cavity, so that infective lesions at the ossifying junctions are less likely to spread to the joint than is the case at the hip or shoulder, where the upper epiphysis lies partly or wholly within the joint; disease in the lower end of the femur is more likely to implicate the knee-joint than disease in the upper end of the tibia.
One of the commonest causes of prolonged disability and feeling of insecurity in the knee, is to be found in the wasting and loss of tone in the quadriceps extensor muscle; the feeling of insecurity is most marked in coming down stairs. The instability of the joint is often added to by stretching of the ligaments and lateral mobility. As a result of both of these factors the joint is liable to repeated slight strains or jars which irritate the synovial membrane and tend to keep up the effusion and excite the overgrowth of its tissue elements.
TUBERCULOUS DISEASE
While tuberculous disease of the knee is specially common in childhood and youth, it may occur at any period of life, and is not uncommon in patients over fifty. The disease originates in the synovial membrane and in the bones respectively with about equal frequency.
When the synovial membrane is diseased, it tends to grow inwards over the articular surfaces (Fig. 122), shutting off the supra-patellar pouch and fixing the knee-cap to the femur, and diminishing the area of the articular surfaces. The ingrowth of synovial membrane may fill up the cavity of the joint, or may divide it up into compartments.
Ulceration of the cartilage and caries of the articular surfaces are common accompaniments.
[Ill.u.s.tration: FIG. 122.--Tuberculous Synovial Membrane of Knee, spreading over articular surface of femur.]
The femur and tibia are affected with about equal frequency, and the nature and seat of the bone lesions are subject to wide variations.
Multiple small foci may be found beneath the articular cartilage of the tibia, or along the margins of the femoral condyles--especially the medial. Caseating foci are comparatively rare, but they sometimes attain a considerable size--especially in the head of the tibia, where they may take the form of a caseous abscess. Sclerosed foci, which form sequestra, are comparatively common (Fig. 123).
[Ill.u.s.tration: FIG. 123.--Lower End of Femur from an advanced case of Tuberculous Arthritis of the Knee. Towards the posterior aspect of the medial condyle there is a wedge-shaped sequestrum, of which the surface exposed to the joint is polished like porcelain.
(Anatomical Museum, University of Edinburgh.)]
#Clinical Types.#--(1) _Hydrops_ usually arises from a purely synovial lesion, but the joint may suddenly become distended with fluid when an osseous focus ruptures into the synovial cavity.
It is met with chiefly in young adults. As the fluid acc.u.mulates it gradually stretches the capsule, and pushes the patella forwards, so that it floats. There is little pain or interference with function; the patient is usually able to walk, but is easily tired. The amount of fluid diminishes under rest, and increases after use of the limb.
In a certain number of cases it may be possible to recognise localised thickening of the synovial membrane, or the presence of floating ma.s.ses of fibrin or melon-seed bodies. This is best appreciated if the knee is alternately flexed and extended by the patient while the surgeon grasps and compresses it with both hands. If the joint is opened, fibrinous material, often in the form of melon-seed bodies, may be found lining the synovial membrane.
Tuberculous hydrops is to be diagnosed from the effusion that results from repeated sprain, from the hydrops of loose body, gonorrha, arthritis deformans, Charcot"s disease, and Brodie"s abscess in the adjacent bone, and from the haemarthrosis met with in bleeders.
(2) _Papillary or Nodular Tubercle of the Synovial Membrane._--This is a condition in which there is a fringy, papillary, or polypoidal growth from the synovial membrane. It is most often met with in adult males. The onset and progress are gradual, and the chief complaint is of stiffness and swelling which are worse after exertion. Sometimes there are symptoms of loose body, such as occasional locking of the joint, with pain and inability to extend the limb; but the locking is easily disengaged, and the movements are at once free again. The patient may give a history of several years" partial and intermittent disability, with lameness and occasional locking, although he may have been able to go about or even to continue his occupation.
There is a moderate degree of effusion into the joint, and when this has subsided under rest it may be possible to feel ill-defined cords, or tufts, or nodular ma.s.ses, and to grasp between the fingers those in the supra-patellar pouch. There is little wasting of muscles, and it is exceptional to have signs of disease of the articular surfaces or of cold abscess.
On opening the joint, there may escape fluid and loose bodies similar to those described under hydrops, and if the finger is introduced into the cavity, the upper pouch is felt to be occupied by fringes or polypoidal processes derived from the synovial membrane.
The diagnosis is to be made from arthritis deformans, and in some cases from loose body of other than tuberculous origin.
(3) _Cold abscess_ or _empyema_ of the knee is a rare condition, in which the joint becomes filled with pus. It usually results from a primary tuberculosis of the synovial membrane occurring in children reduced in health and the subject of tuberculosis elsewhere.
(4) _Diffuse Thickening of the Synovial Membrane--White Swelling._--So long as this form of the disease remains confined to the synovial membrane, the chief feature is that of an indolent elastic swelling in the area of the joint. The swelling tapers off above and below, so that it acquires a fusiform shape, and from the wasting of the muscles it appears greater than it really is. The range of movement is moderately restricted.
At first the patient limps, keeps the knee slightly flexed, and complains of tiredness and stiffness after exertion. As the articular surfaces become affected, there is pain, which is readily excited by jarring of the limb, or by any attempt at movement; the joint is held rigid, and there may be startings at night. If untreated, flexion becomes more p.r.o.nounced--it may be to a right angle--the leg and foot are everted, and, in children, the tibia may be displaced backwards (Fig. 124). The wasting of muscles continues, the part becomes hot to the touch, the swelling increases, and may show areas of softening or fluctuation from abscess formation.
[Ill.u.s.tration: FIG. 124.--Advanced Tuberculous Disease of Knee, with backward displacement of Tibia.]
White swelling is to be differentiated from peri-synovial gummata, from myeloma and sarcoma of the lower end of the femur, and from bleeder"s knee. In the first of these the swelling is nodular and less uniform, and there may be tertiary ulcers or depressed scars in the neighbourhood of the patella. In tumours the swelling is more marked on one side of the joint, it is uneven or nodular, it does not correspond to the shape of the synovial membrane, and may extend beyond the limits of the joint, and it involves the bone to a greater extent than is usual in disease of the joint. Skiagrams show expansion of the bone in central tumours, or abundant new bone in ossifying sarcoma. The diagnosis of bleeder"s knee is to be made from the history.
(5) _Primary Tuberculous Disease in the Bones of the Knee._--So long as the foci are confined to the interior of the bone, it is impossible to recognise their existence, unless they are of sufficient size to cause enlargement of the bone or to be discernible in a skiagram.
#The formation of peri-articular abscess# takes place in rather more than fifty per cent. of cases. When left to themselves, such abscesses tend to spread up the thigh, or down the back of the leg between the superficial and deep layers of calf muscles, and numerous sinuses may result from their rupture through the skin.
#Att.i.tudes of the Limb in Knee-Joint Disease.#--The att.i.tude most often a.s.sumed is that of _flexion_, with or without _eversion of the leg and foot_. The flexion is explained by its being the resting att.i.tude of the joint, and that which affords most ease and comfort to the patient. Once the joint is flexed, the involuntary contraction of the flexor muscles maintains the att.i.tude, and if the patient is able to use the limb in walking, the weight of the body is a powerful factor in increasing it. The eversion of the leg is probably a.s.sociated with contraction of the biceps muscle. _Backward displacement of the tibia_ is met with chiefly in neglected cases of chronic disease of the knee when the child has walked on the limb after it has become flexed.
In certain cases, _genu valgum_ or abduction of the leg is present along with a slight degree of flexion. The valgus att.i.tude is a.s.sociated with slight lateral displacement of the patella, with prominence and apparent enlargement of the medial condyle, with depression of the pelvis on the diseased side and apparent lengthening of the limb.
#Treatment of Tuberculous Disease of the Knee.#--Conservative measures are always indicated in the first instance, and are persevered with so long as there is a prospect of obtaining a movable joint.
_Conservative Treatment._--If the joint is sensitive and tends to be flexed, the patient is confined to bed, the limb is secured to a posterior splint, and extension with weight and pulley persevered with until these symptoms have disappeared; during this time, from three to six weeks, methods of inducing hyperaemia and other anti-tuberculous procedures are employed. If it is proposed to inject iodoform or other drug, the needle is inserted into the interval between the bones on the medial side of the ligamentum patellae or into the upper pouch when this is distended with fluid.
If there is no pain or tendency to flexion, or when these have been overcome, the limb is put up in a Thomas" splint (Fig. 125) and the patient allowed to go about. The splint is worn for a period varying from six to twelve months; before being discarded it may be left off at night; it is ultimately replaced by a bandage.
[Ill.u.s.tration: FIG. 125.--Thomas" Knee Splint applied. Note extension strapping applied to affected leg, and patten under sound foot.]