Kneecap Health Dictionary

The hinge joint between the femur (thighbone) and tibia (shin). The patella (kneecap) lies across the front of the joint. Two protective discs of cartilage called menisci (see meniscus) cover the surfaces of the femur and tibia to reduce friction. Bursas (fluid-filled sacs) are present above and below the patella and behind the knee. External ligaments on each side of the joint provide support. Cruciate ligaments within the joint prevent overstraightening and overbending of the knee. The quadriceps muscles on the front of the thigh straighten the knee; the hamstring muscles at the back of the thigh bend it.

Knee injuries are common.

They include ligament sprains, torn meniscus, dislocation of the patella, and fracture of any of the bones in the joint.

Chondromalacia patellae is common in adolescents.... knee

The kneecap (see knee).... patella

Inspection through an endoscope (viewing tube) of the interior of a joint.

Arthroscopy is most often used to diagnose disorders of the knee joint but can also be used in other joints such as the shoulder, hip, or wrist.

It allows the surgeon to see the surface of the bones, the ligaments, the cartilages, and the synovial membrane.

Specimens can be taken for examination.

Some surgical procedures, such as removal of damaged cartilage, repair of ligaments, and shaving of the patella (kneecap), are usually performed arthroscopically.... arthroscopy

A painful disorder of the knee in which the cartilage behind the patella (kneecap) is damaged.

Adolescents are most commonly affected.

The condition may result from knee injuries or sporting activities in which the knee is bent for long periods.

This action weakens the inner part of the quadriceps muscle (at the front of the thigh) causing the patella to tilt when the knee is straightened and rub against the lower end of the femur.

The cartilage that covers both bones becomes roughened, causing pain and tenderness.

Treatment is with analgesic drugs and exercises to strengthen the thigh muscles.

Rarely, surgery may be needed.... chondromalacia patellae

Temporary reddening of the face, neck, and upper trunk that is accompanied by a sensation of heat and is often followed by sweating. Hot flushes are usually caused by decreased oestrogen production during or after the menopause, and they sometimes occur following removal of the ovaries (see oophorectomy). Hot flushes can often be alleviated by treatment with hormone replacement therapy (HRT).

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housemaid’s knee Inflammation of the bursa that acts as a cushion over the kneecap. The inflammation is usually caused by prolonged kneeling but may develop after a blow to the front of the knee. (See also bursitis.)... hot flushes

A surgical procedure in which all or part of a damaged meniscus (cartilage disc) is removed from a joint, almost always from the knee. Meniscectomy may be carried out when damage to the meniscus causes the knee to lock or to give way repeatedly. The procedure cures these symptoms and reduces the likelihood of premature osteoarthritis in the joint.

Arthroscopy may be carried out to confirm and locate the damage, and the damaged area removed by instruments passed through the arthroscope.

Alternatively, the meniscus may be removed through an incision at the side of the patella (kneecap).

In either case, there may be an increased risk of osteoarthritis in later life, but this is less than if the damaged meniscus had been left in place.... meniscectomy

n. softening, inflammation, and degeneration of cartilage at a joint. Chondromalacia patellae is the most common kind, affecting the undersurface of the kneecap; it results in pain in the front of the knee and grating (*crepitus), which is made worse by kneeling, squatting, and climbing stairs. Treatment includes physiotherapy, ice packs, anti-inflammatory drugs (NSAIDs), weight loss, and avoidance of aggravating factors, such as running and jumping.... chondromalacia

(prepatellar bursitis) inflammation and resultant swelling of the bursa in front of the kneecap, usually due to repetitive friction and pressure over the kneecap, as from frequent episodes of prolonged kneeling. Treatment includes pressure bandaging, *NSAIDs, and avoidance of kneeling. See bursitis.... housemaid’s knee

an oval nodule of bone that lies within a tendon and slides over another bony surface. The patella (kneecap) and certain bones in the hand and foot are sesamoid bones.... sesamoid bone

a star-shaped fracture of the kneecap caused by a direct blow. The bone may be either split or severely shattered; if the fragments are displaced, the bone may need to be surgically repaired or rarely removed (patellectomy).... stellate fracture

(thigh bone) n. a long bone between the hip and the knee (see illustration overleaf). The head of the femur articulates with the acetabulum of the *hip bone. The greater and lesser trochanters are protuberances on which the gluteus and psoas major muscles, respectively, are inserted. The lateral and medial condyles articulate with the *tibia, and the trochlear groove accommodates the kneecap (patella).

The narrowed end of the femur (femoral neck), which carries the head, is the commonest site of fracture of the leg in elderly women. Partial dislocation of the femoral epiphysis, the growth area of the upper end of the bone, leads to deformity of the head of the femur and premature degeneration of the hip joint.... femur

(knee jerk) reflex contraction of the quadriceps (thigh) muscle so that the leg kicks, elicited in a patient sitting with one knee crossed over the other by sharply tapping the tendon of the muscle below the kneecap. The reflex is mediated through nerves emanating from the third and fourth lumbar spinal levels (see spinal nerves). This is a test of the connection between the sensory nerves attached to stretch receptors in the muscle, the spinal cord, and the motor neurons running from the cord to the thigh muscle, all of which are involved in the reflex. The patellar reflex is reduced or absent when there is disease or damage of the spinal cord at or below the level of the reflex and exaggerated in disorders above the level of the reflex.... patellar reflex