Manual of Surgery Volume Second: Extremities—Head—Neck. Sixth Edition.

by Alexis Thomson; Alexander Miles

Torn or Lacerated Meniscus.—In a large proportion of cases of displaced meniscus in which the condition assumes the recurrent type, it is found, on opening the joint, that, in addition to being unduly mobile, the meniscus is torn or lacerated. The experience of surgeons varies regarding the nature of the laceration. In our experience the most common form is a longitudinal split, whereby a portion of the inner edge of the cartilage is separated from the rest and projects as a tag towards the centre of the joint ([Fig. 86]). As a rule, it is the anterior end that is torn, less frequently the posterior end. Sometimes the meniscus is split from end to end, the outer crescent remaining in position, while the inner crescent passes in between the condyles and lies curled up against the cruciate ligaments. Occasionally the anterior end is torn from its attachment to the tibia, less frequently the posterior end. In one case we found the meniscus separated at both ends and lying between the bones and the capsule.

The clinical features are similar to those of mobile meniscus with displacement, and as a rule the exact nature of the lesion is only discovered after opening the joint.

The treatment consists in excising the loose tag or the whole meniscus, according to circumstances. The recovery of function is usually complete. It is not advisable to attempt to stitch the torn portion in position.

Rupture of the Cruciate Ligaments.—A few cases have been recorded in which, as a result of severe twisting forms of violence, the cruciate ligaments have been torn from their attachments, leaving the joint loose and unstable, so that the tibia and the femur could be moved from side to side on one another. When the disability persists, the joint may be opened and the ligaments sutured in position (Mayo Robson).

Sprains of the knee are comparatively common as a result of sudden twisting or wrenching of the joint. In addition to the stretching or tearing of ligaments, there is usually a considerable effusion of fluid into the synovial cavity, and examination with the X-rays occasionally reveals that a portion of bone has been torn away with the ligament—sprain-fracture. The swelling fills up the hollows on either side of the patella, and extends for some distance in the synovial pouch underneath the quadriceps. The patella is raised from the front of the femur by the collection of fluid in the joint—“floating patella”—and, if firmly pressed upon, it may be made to rap against the trochlear surface.

A sprain is to be diagnosed from separation of one or other of the adjacent epiphyses, fracture involving the articular ends of the bones, and displacement of the semilunar menisci. On account of the swelling, which obscures the outline of the part, the differential diagnosis is often difficult, but as the swelling goes down under massage it becomes easier. Chief reliance is to be placed upon the bony points retaining their normal relationships, and upon the fact that the points of maximum tenderness are over the attachments of one or other of the collateral ligaments. As the tibial collateral ligament suffers most frequently, the most tender spot is usually over its attachment to the medial aspect of the head of the tibia—less frequently over the medial condyle of the femur.

Unless efficiently treated, a sprain of the knee is liable to result in weakness and instability of the joint from stretching of the ligaments, and this is often associated with effusion of fluid in the synovial cavity (traumatic hydrops). This is more likely to occur if the joint is repeatedly subjected to slight degrees of violence, such as are liable to occur in football or other athletic exercises—hence the name “footballer's knee” sometimes applied to the condition.

A further cause of disability, following upon sprains of the knee, is wasting of the quadriceps muscle. The stability of the joint, whenever the position of full extension has been departed from, is largely dependent upon its capacity of controlling the amount of flexion, notably in descending a stair or in walking on uneven ground, hence it is that with a wasted quadriceps there is increasing liability to a repetition of the sprain. With each repetition of the sprain, there is an addition to the fluid in the joint, stretching of ligaments, and further wasting of the quadriceps. A form of vicious circle is established in which there is at the same time increased liability to sprain and diminished capacity of recovering from it. Even after the repair of the damaged ligament or the removal of the mobile or torn meniscus, wasting of the quadriceps remains a source of weakness and disability and calls for treatment by massage and electricity.

Treatment.—In recent and severe cases the patient must be confined to bed, and firm pressure applied over the joint by means of cotton wool and a bandage. This may be removed once or twice a day to admit of the joint being douched, and at the same time it should be massaged and moved to promote absorption of the effusion and prevent the formation of adhesions.

Chronic effusion into the joint is most rapidly got rid of by rest and blistering. If the patient is unable to lie up, massage should be systematically employed, and a firm elastic bandage worn. A patient who has once had a severe sprain of the knee, or who has developed the condition of “footballer's knee,” must give up violent forms of exercise which expose him to further injuries, otherwise the condition is liable to be aggravated and to result in permanent impairment of the stability of the joint.