GO 



ABNORMAL CONDITIONS OF THE KNEE-JOINT. 



He found it necessary, however, after the lapse 

 of three years, to seek re-admission into the 

 hospital, where he now is. The right knee- 

 joint is now enlarged, and in a condition simi- 

 lar to that of the left on his first admission. 

 The latter, on the contrary, has nearly resumed 

 its normal condition ; the dropsical effusion of 

 synovia has disappeared ; he does not com- 

 plain of pain in it ; but if the joint be accu- 

 rately examined, the bony irregularities which 

 were noticed on the head of the tibia will be 

 found, as might be expected, still to exist. If 

 we move the patella transversely, an articular 

 crepitus is perceived, plainly shewing that the 

 cartilages have been removed from the patella 

 and corresponding trochlea of the femur. The 

 edges of the trochlea can also be felt through 

 the skin to be elevated into rising crests. The 

 peculiar crackling noise which is elicited when 

 the joint is flexed and extended is infinitely 

 more remarkable in the left knee-joint now, 

 when it is comparatively well, than formerly, 

 when it was much swollen, and when the syno- 

 vial membrane was in what has been called a 

 dropsical condition. 



Anatomical characters. When we have an 

 opportunity of making an anatomical examina- 

 tion of a knee in which the disease had been 

 fully established, we find the synovial fluid 

 increased in quantity, and but little altered in 

 its sensible qualities. The membrane is thicker 

 than natural, and opaque. Sometimes vascular 

 synovial fimbriae are formed, and hang into the 

 synovial sac.* We also find moveable carti- 

 laginous bodies in the interior, similar to those 

 noticed in the elbow-joint.f (See ELBOW, 



ABNORMAL CONDITIONS OF.) 



In the line of flexion and extension we 

 observe narrow sulci formed by the removal of 

 the cartilages. On examining the popliteal 

 tumour, we find it to be, what we might have 

 surmised, an enlargement and dropsical condi- 

 tion of the bursa, which naturally exists at the 

 point of decussation of the semi-memhranosus 

 tendon with the tendon of the internal head of 

 the gastrocnemius. This bursa communicates 

 normally with the synovial sac of the knee- 

 joint by a very small circular aperture. It is 

 not an uniform ovoid sac, but evidently has 

 semilunar septa irregularly thrown across its 

 interior, making the bursa a small mullilocular 

 cavity. When the joint is much distended by 

 synovial fluid, the bursa admits some of this 

 fluid, and takes upon itself the same morbid 

 process which affects the proper synovial mem- 

 brane of the joint itself. As we examine the 

 disease when it has existed for some time, we 

 find that the cartilage has been removed in 

 grooves, and its place supplied by a porcelain- 

 ous or ivory deposit. The bones of the knee- 

 joint, however, present appearances charac- 

 teristic enough : they generally appear to be 

 enlarged. This is obviously the case with the 

 patella : it is broader than natural, excavated, 

 and grooved vertically. All the bones seem 

 enlarged and porous on all those parts of the 



articular surfaces which have not been worn by 

 use into porcelainous polished surfaces and sulci. 



The cavities of the head of the tibia for the 

 reception of the condyles of the femur are 

 much deepened, and exuberant nodules or 

 vegetations of bone are thrown out around the 

 circumference of this head. When we examine 

 the femur, we find here also bony vegetations, 

 arranged along the lateral margins of the con- 

 dyles, similar to those which we noticed around 

 the corona of the head of the femur.* The 

 part of this bone called the trochlea, upon 

 which the patella moves, is also grooved verti- 

 cally, and the trochlea has rising edges to it, 

 or crests, which will be found to correspond to 

 the lateral margins of the patella when this 

 bone is laid upon the trochlea of the femur. 

 The anatomical characters of this disease when 

 it has existed long, will of course be still more 

 strongly marked. However, the dropsical 

 effusion into the synovial sac will be found to 

 be much less as the disease is of longer dura- 

 tion. The joint becomes more and more flexed, 

 the tibia has a tendency to be partially dis- 

 placed outwards, and the toe is everted : the 

 patella under such circumstances is dislocated 

 on the external condyle, giving us another 

 example of this luxation from disease. In the 

 interior of the joint foreign bodies are found, 

 while the articular and semilunar cartilages are 

 altogether absorbed. 



White swelling, or chronic strumous arthritis 

 of the knee. The knee-joint is more liable to 

 the disease commonly called white swelling 

 than any other articulation. This disease, 

 though utterly insidious in its attack and slow 

 in its progress, nevertheless presents some of 

 the characters of an inflammatory complaint 

 during its whole course. The first symptom 

 generally is reported as a deep-seated dull 

 heavy pain unattended by swelling and not 

 increased by motion, but in children the swell- 

 ing is often the first symptom noticed. This is 

 followed by pain, which, although it comes 

 only occasionally, is severe, and is referred 

 almost uniformly to the inside of the knee. 

 Some increase of temperature of the affected 

 joint on comparison with the other knee, can 

 be ascertained. 



The swelling does not at first encompass the 

 whole joint, but first appears on the anterior 

 and lower part of the knee, occupying in 

 general the two little hollows on the different 

 sides of the ligament which joins the patella to 

 the tibia. This swelling is elastic, and on 

 examination by the finger conveys a sense of 

 softness and fluctuation, as if it contained a 

 fluid, although no fluid to any amount teally 

 exists. The skin over the knee becomes pale 

 and shining, as if thinned. The subcutaneous 

 veins dilate and become very evident. The 

 muscles of the leg waste, so that the volume 

 of this portion of the affected extremity is con- 

 siderably reduced, and the inferior part of the 

 thigh just over the knee suffers a characteristic 

 diminution in the measure of its circumference. 



* See Cruveilhier, liv. 9. pi. 6. 



t See Morgagni's case, in note above. 



* See HIP, ABNORMAL CONDITION OF, 



also Cruveilhier, liv. 9. pi. 6. Jig. 2. 



