ABNORMAL CONDITIONS OF THE KNEE-JOINT. 



75 



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 

 relaxed 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 

 witli 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." 



The complaint, Mr. Hey apprehends, may be 

 brought on by any such alteration in the state 

 of the joint as will prevent the condyles of the 

 os femoris from moving truly in the hollow 

 formed by the semilunar cartilages and articular 

 depressions of the tibia. According to him, an 

 unequal tension of the lateral or cross ligaments 

 of the 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 his bed, when, the clothes 

 not suffering the foot to turn with the body, the 

 thigh-bone has slipped from its semilunar carti- 

 lage. 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 



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, eet. 37, has often dislocated his knee, turning 

 the foot inwards, and the thigh-bone outwards, 

 by accidentally slipping on uneven ground, or 

 by sudden exertions 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, aet. 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 manoeuvre 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 



