Internal derangement of the knee——* The 
___ knee-joint,” says Mr. Hey, “is not unfrequently 
affected with an internal derangement of its 
“component parts, and this sometimes in conse~ 
quence of trifling accidents. The defect is, 
_ indeed, now and then removed as suddenly as 
it is produced, by the natural motions of the 
_ joint without surgical assistance; but it may 
remain for weeks or months, and will then be- 
_ come a serious misfortune, as a considerable 
degree of lameness may remain. This disorder 
‘may happen either with or without contusion. 
_ In the latter case the accident is easily distin- 
_ guished from all others. The joint, with respect 
_ to external form, seems perfect; if there be any 
_ difference from its natural appearance, it is, that 
_ the ligament of the patella appears rather more 
telaxed than in the sound limb. The leg is 
readily bent and extended by the hands of the 
surgeon, and without pain to the patient; at 
_ most the degree of uneasiness caused by this 
_ flexion and extension is trifling ; but the patient 
himself cannot freely bend, or perfectly extend 
_ the limb in walking; he is compelled to walk 
_ with an invariable and small degree of flexion. 
_ Though the patient is obliged to keep the leg 
_ thus stiff in walking, yet in sitting down the 
__ affected joint will move like the other.” 
_ Thecomplaint, Mr. Hey apprehends, may be 
__ brought on by any such alteration in the state 
_ of the joint as will prevent the condyles of the 
0s femoris front moving truly in the hollow 
_ formed by the semilunar cartilages and articular 
_ depressions of the tibia. According to him, an 
8g tension of the lateral or cross ligaments 
of joint, or some slight derangement of 
the semilunar cartilages, may probably be suffi- 
cient to predispose any one to this accident. 
Sir A Cooper, in alluding to the internal de- 
rangement of the knee-joint described by Hey, 
calls the accident a “ partial luxation of the 
thigh-bone from the semilunar cartilages ;” but 
it does not appear to us that he had any oppor- 
tunity of ascertaining the anatomy of such an 
accident. Sir A. Cooper has observed it to 
occur most frequently, when a person in walking 
strikes his toe, the foot being at the time everted, 
against any projecting body, as the fold of a 
carpet, after which the patient feels pain in the 
knee, which cannot be extended. He has also 
seen this accident happen from a person having 
suddenly turned in iis bed, when, the clothes 
not suffering the foot to turn with the body, the 
_ thigh-bone has slipped from its semilunar carti- 
He also states that he has known it occur 
from a sudden twist of the knee inwards when 
the foot was turned out. He says, “ under ex- 
treme degrees of relaxation, or in cases in which 
there has been increased secretion into the joint, 
the ligaments become so much lengthened as to 
allow the cartilages to glide upon the surface of 
the tibia, and particularly when pressure is 
_ made by the thigh-bone on the edge of the car- 
 tilage. The cartilages which receive the con- 
: dyles of the os femoris are united to the tibia 
__ by ligaments; and when these ligaments become 
extremely relaxed and elongated, the cartilages 
are easily pushed from their situations by the 
| condyles of the os femoris, which are then 
ABNORMAL CONDITIONS OF THE KNEE-JOINT. 
75 
brought into contact with the head of the tibia; 
and when the limb is attempted to be extended, 
the edges of the semilunar cartilages prevent 
it.” It may be inferred from his observations 
that the accident may occur either at the internal 
condyle, which is the more common, or at the 
external, and that the position of the foot at the 
time of the occurrence of the accident has much 
influence in determining which of the semilunar 
cartilages is to be displaced. Thus, if the toe 
be everted, the displacement of the internal 
cartilage will occur; on the contrary, if the foot 
be fixed and inverted at the moment of the 
accident, the subluxation of the external con- 
dyle of the femur from the external semilunar 
cartilage will be the accident. Sir A. Cooper 
adduces the following case. Mr. Henry Dob- 
ley, et. 37, has often dislocated his knee, turning 
the foot inwards, and the thigh-bone outwards, 
by accidentally slipping on uneven ground, or 
by sudden ae of the limb. Considerable 
pain was immediately produced, accompanied 
with a great deal of swelling. His mode of 
reducing it is as follows. He sits upon the 
ground, and then bending the thigh inwards, 
and pulling the foot outwards, the subluxation 
of the os femoris being external, the natural 
position of the limb becomes restored. 
Mr. L. a well-formed gentleman, et. 29, 
has consulted me twice or thrice these last 
two years concerning this internal derangement 
of the knee-joint so well described by Hey. 
Mr. L. complains that, whenever he un- 
guardedly flexes the knee suddenly, the toe at 
the time being much inverted, he is instanta- 
neously seized with very disagreeable sensa- 
tions in the knee-joint, not amounting to pain. 
There is a sudden sense of weakness across 
the front of the joint, the limb is semiflexed, 
and a great feeling of tightness and stiffness 
exists behind, along the course and about the 
insertion of the biceps tendon. All these 
symptoms come on suddenly from some awk- 
ward movement or false step, such as, in walk- 
ing, putting his foot into some unexpected 
hole, but so very suddenly does the internal 
derangement occur, that, if walking at the mo- 
ment, he generally falls to the ground. After 
a little time, though lame, he is able to walk, 
and to place the heel to the ground, and though 
he usually keeps the limb slightly flexed, he 
can at will extend it. These accidents are 
usually followed by some effusion of synovial 
fluid into the joint. I have practised with 
success the extension and sudden flexion of the 
limb advised by Hey, and my patient has him- 
self occasionally, and with success, directed 
this maneeuvre to be practised on him by his 
servant, or by any one who happened to be at 
hand when the accident occurred. He attri- 
butes the first cause of this liability to the 
sudden derangement of the articulation to a 
violent sprain of the knee-joint he got while 
ringing a young and powerful horse; the latter 
pulled away from him with such violence, that 
Mr. L. fell to the ground, and during the 
fall he felt as if something at the internal 
side of the knee-joint had been broken: the 
thigh and tibia were bent in such a manner as 
