ABNORMAL CONDITIONS OF THE KNEE-JOINT. 



69 



which followed was inconsiderable, and in the 

 second an opporiunity for " secondary ampu- 

 tation" was afforded even after acute inflam- 

 mation of the joint had taken place. 



A healthy labourer, about 30 years of age, 

 was admitted into Jervis-street Hospital about 

 eight years ago, under the care of the late Mr. 

 M allace, for a comminuted, but still a simple 

 fracture of the lower extremity of the femur, 

 where it entered into the formation of the 

 knee-joint. The accident was attended with 

 enormous effusion, and there was a degree of 

 mobility of the limb in the seat of the commi- 

 nuted fracture truly astonishing ; but little in- 

 flammation followed, and under the simplest 

 treatment the man ultimately recovered with a 

 stiff 1 knee-joint. The second case was that of 

 a boy aged 13 years, who had received a simple 

 fracture of the lowest part of the shaft of the 

 femur. The condyles of this bone were de- 

 tached at their normal line of junction with the 

 shaft, and where they are covered with syno- 

 vial membrane ; the posterior and anterior cru- 

 cial ligaments were separated from the femur, 

 and had carried with them small portions of 

 this bone. The result of the operation is not 

 recorded, but the specimen, preserved in our 

 museum at the Richmond School of Medicine, 

 exhibits, besides the injury the bones received, 

 traces of the very acute inflammation which 

 followed, particularly on the surface of the sy- 

 novial membrane, which is covered with lymph. 

 The periosteum of the femur in the vicinity of 

 the fracture is much thickened and detached all 

 round from the femur. 



Among the valuable preparations presented 

 by Mr. Kirby to the College of Surgeons in 

 Dublin is a specimen of one of these transverse 

 fractures of the lower extremity of the femur, 

 which was combined with a vertical split of 

 the bone down through the trochlea and outer 

 condyloid fossa. Although the fracture was a 

 simple one, it was followed by enormous effu- 

 sion, succeeded by acute inflammation of the 

 structures of the joint ; and Mr. Kirby in- 

 forms me that amputation was successfully re- 

 sorted to. The synovial membrane was much 

 thickened, and evidences of acute inflammation 

 of the structures of the knee-joint are still to be 

 seen in the preparation. 



Fractures of the tibia close to the knee-joint 

 may be transverse, or through the line of junc- 

 tion of the epiphysis with the rest of the tibia 

 in the young subject, or in the situation and 

 direction of this line in the adult. In this case 

 the broad surfaces of the broken tibia nearly 

 maintain their relations with each other. If 

 there be any displacement, it will be that of 

 the superior fragment, which will be drawn 

 backwards towards the popliteal space, as the 

 inner hamstring muscles will draw the bone in 

 this direction. 



Oblique fractures of the upper extremity of 

 the tibia which run into the knee-joint are 

 accompanied with symptoms not very dissi- 

 milar from those belonging to oblique fractures 

 of the internal condyle of the femur, except 

 the situation of the pain, and the crepitus which 

 can be elicited on motion being communicated 



to the broken portion of bone. There is the 

 same sudden effusion into the knee-joint, and 

 a very great degree of lateral motion is allowed, 

 which is a movement the knee-joint does not 

 normally possess. 



We learn from Blandin that Beclard had 

 very frequently observed elderly females to be 

 the subjects of fractures of the upper portion 

 of the tibia, produced by the contraction of 

 the flexor muscles of the leg, which muscles 

 also he observed uniformly pulled the supe- 

 rior fragment into the hollow of the ham. The 

 explanation of the fracture occurring from such 

 a cause must be referred to the atrophy which 

 the head of the tibia undergoes in elderly 

 people, in consequence of which the tibia be- 

 comes thin in its shell, and the interior os- 

 seous structure reduced to a thin reticular 

 tissue, which in the dead subject we notice to 

 yield to the slightest pressure of the fingers. 

 We have known this atrophy of the tibia to 

 exist in adults as well as in old subjects, and 

 when present, it of course renders the bone 

 liable to be broken by slight causes. More- 

 over, we have usually found the species of 

 reunion of the .broken bone which can be 

 effected under such circumstances to have been 

 very imperfect ; the patient after a long period 

 endeavours to move about with the assistance 

 of crutches ; and effusion takes place into the 

 knee-joint, the functions of which become 

 greatly impaired for the rest of life. 



Fracture of the patella. This fracture oc- 

 curs almost always in the transverse direction ; 

 it is rarely oblique, and still more rarely longi- 

 tudinal ; sometimes a fracture divides this bone 

 into three or four pieces, or is what is called 

 comminuted. The longitudinal fracture is rare, 

 and this and the comminuted are generally the 

 result of direct violence; and, although the 

 transverse fracture may depend on a similar 

 cause, still the violent contraction of the ex- 

 tensor muscles of the leg is the most frequent 

 source of this accident. When a fall occurs 

 directly on the front of the knee, this joint 

 being at the moment in a state of semiflexion, 

 if a fracture take place it will no doubt be 

 considered as the result of the fall directly on 

 the bone, by which it is broken ; certainly 

 muscular action may lend its assistance to the 

 external violence even in producing the frac- 

 ture, and after this has occurred, to cause the 

 separation of the fragments. 



This fracture cannot so readily be effected 

 by muscular action when the limb is in a state 

 of complete extension as when it is in a com- 

 mencing state of flexion, because in complete 

 extension the muscles act in the direction of the 

 long axis of the bone ; but in flexion at the 

 knee to the first degree the patella is in a par- 

 ticular condition, which is favourable to the 

 production of fracture ; it only applies itself 

 to the condyles of the femur by its middle 

 point. The base and summit of this bone are 

 unsupported ; the extensor muscles of the leg 

 on one side, and the tendon or ligament of the 

 patella on the other, are, in this position of 

 the joint, oblique with relation to the long 

 axis of the patella ; the muscles then bend the 



