IF SYMPTOMS PERSIST
“All of this and the curious knee-cap
fitted above the wrought greaves…”
Hilda Doolittle (1886-1961) U.S. poet
“Loss” in “Sea Garden” (1916)
Life is harsh. We say a woman’s legs are ugly if they are bony and her kneecaps, knobby. We say a man is “weak-kneed” if he lacks willpower and resolution. But to a bone doctor, knees are ugly and weak when these give way. Indeed, for the knees, form is function.
The patella. The kneecap is properly, the patella (Latin diminutive of patina, a shallow dish). In the normal knee, it occupies the groove on top of the thigh bone (femur). As the leg is bent and straightened, the patella is pulled up and down. That is one of its three main functions, to provide a fulcrum for the thigh front muscles (the quadriceps), allowing easy and efficient motion. The kneecap provides lubrication and nutrition to the joint. It protects it as well.
Unstable kneecap. Sitting, standing, squatting are effortless movements when the kneecap sits nicely on the thigh bone groove. If the kneecap is deformed or damaged, or if the groove is shallow, the so-called “tracking” will be flawed. The kneecap will “jump its tracks”. The result is a patellar dislocation.
Risk factors. The following increase the likelihood of a knee giving way. Some are:
- A positive family history
- Participation in high risk sports such as basketball, football, and gymnastics
- High level of competition in youth
- Age younger than 14 years
- A very movable knee cap
Females are more often afflicted than males. Recurrence of patellar dislocation is age-dependent. It will recur in 60 percent of patients between 11 and 14 years old, 30% in young adults 19 to 28 years old and rarely in older adults.
Signs and Symptoms. In an acute dislocation, the patient’s knee is fully bent (hyperflexed) because the muscles at the back of the thigh or hamstrings are in spasm. It is unusual to find the patella still dislocated. More often, the kneecap spontaneously reduces and the examining doctor records the aftermath. Thus, the area around the knee will be very tender and swollen with signs of bleeding from the inside (hemarthrosis). Also, the so-called positive apprehension sign means that any attempt to re-dislocate the kneecap produces a disagreeable demeanor, short of “If you touch my kneecap again, I’ll kill you!”
What to do. Xrays of the knee need to be taken at the emergency room to confirm spontaneous reduction. Otherwise, the kneecap is reduced by extending the knee. The knee is immobilized in a compression dressing or a brace. Physical therapy must be started as early as two weeks after injury. The problem, of course, is in the repeating dislocations. These cases have to be carefully studied because many surgical procedures address different causes of dislocation. The patient is also educated to re-train the knee in ways that avoid dislocation. The ultimate sacrifice is avoiding the high-risk activity that produced the dislocation.
Seventy-five percent of patients with patellar dislocation respond well to conservative means. Most can expect to have “beautiful” knees and and be “strong-kneed,” orthopedic-wise.
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