Disorders of the Hip
The hip is the joint between the upper end of the femur (thighbone) and the acetabulum, the cuplike structure in your pelvic bone. This ball-and-socket joint allows your leg to move forward and backward, to move from side to side, and to rotate to the left and the right. The femur and the pelvis are attached by liga- ments. The hip supports the pelvis, the abdomen, and the chest and allows you to stand and move.
Wear and tear on the hip can result in bursitis (the most common cause of hip pain; see page 305) or osteoarthritis (see page 308). Bursitis can cause pain on the outer side of the hip that worsens after lying on that side, walking, or climb- ing stairs. Bursitis in the area of the upper buttocks is most noticeable while walking uphill or after sitting for a long period on a hard surface.
Osteoarthritis in the hip can progress to the point where joint replacement is required (see page 310). The bones in the hip also can be weakened by osteo- porosis (see page 301), which can result in a hip fracture after a fall or an injury.
Disorders of the Knee
The knee is a modiﬁed hinge joint between the femur (thighbone) and the tibia (shin bone). The knee allows
you to bend and straighten your leg. It also allows slight rotation of the lower leg when the knee is bent. Your hamstring muscles bend the knee, while your quadri- ceps muscles straighten the knee. Strong ligaments join your femur to your lower leg bones (tibia and ﬁbula) and limit side-to-side movement, overextension, and over- bending of the knee. The ligaments also limit sliding movement between the bones. Your knee also has two menisci (crescent-shaped disks of cartilage) to reduce friction and distribute the weight-bearing load evenly
during walking or running. The knee joint is vulnerable to injury from the front or either side, as well as from overextension. Injury can affect the menisci or any of the ligaments, bursae, cartilage, bones, or tendons that form the knee. The knee is prone to a number of disorders and injuries because of its special design and because it bears weight and provides movement.
A torn ligament usually results from a severe twist or a forceful blow to the knee when the knee is bent and then straightened. It also can occur when the foot is placed ﬁrmly on the ground and the leg is straightened while the knee is twisted. Each ligament in the knee is subjected to tremendous stress and strain. Injuries to ligaments usually cause immediate pain that is present even at rest. The pain increases when the knee is bent or when weight is put on the knee. The joint also
may be swollen and warm. There may be stiffness, and movement may be lim- ited. You may hear or feel a “pop,” and your knee may give out when the liga- ment tears. Injury to a ligament on the side of the joint causes pain in that side of the knee. Injury to a ligament within the joint causes pain deep inside the knee.
Ligament injuries are ﬁrst treated with RICE (see page 65). You also must use some form of support (such as crutches or a cane) to avoid putting weight on the injured knee joint. In some cases a splint or a brace is needed for long-term immobilization of the joint. Nonsteroidal anti-inﬂammatory drugs such as aspirin or ibuprofen will help relieve pain and reduce inﬂammation. Arthroscopy (see box) often is needed to repair the ligament. Your knee joint may be unstable after this injury and may be more susceptible to recurring ligament or cartilage tears. Your doctor may recommend working with a physical therapist or an ath- letic trainer on exercises that will stabilize the ligaments and tendons and strengthen the leg muscles.
Arthroscopy is a procedure that uses an arthro- scope (a viewing tube with a tiny video- camera at its tip) to examine, diagnose, and treat joint problems. The procedure is usually done on the knee joint, but it can be performed on other joints, such as the shoulder, elbow, ankle, hip, and wrist. For arthroscopic surgery, the surgeon makes a small incision and inserts the arthro- scope directly into the joint. The procedure can be observed on a video monitor and videotaped. Surgical instruments are inserted into the joint through other small incisions. Any loose bone, cartilage, or other material in the joint also can be removed. A biopsy (removal of a small piece of tissue from the joint for examination under a microscope) can be easily performed during
Arthroscopic surgery is performed to examine and repair the following:
• torn rotator cuff (the muscles and tendons sur- rounding the shoulder joint)
• torn meniscus (a crescent-shaped disk of carti- lage found in the knee joint)
• torn or damaged ligaments
• torn cartilage
• inﬂamed tendon sheaths
General, local, or spinal anesthesia is used, depending on the joint. Most people do not require strong pain medication afterward and can usually resume light normal activities within a few days. However, after arthroscopic knee surgery, a person must wear a knee brace and have physical therapy on the joint for several weeks or months to pro- mote healing and prevent further injury.
Either meniscus in the knee can be torn during sharp, rapid, twisting motions. The incidence of this type of injury rises with age and participation in sports that require quick, reactive movements, such as basketball, downhill skiing, and soc- cer. Certain knee motions cause a popping sensation, sometimes accompanied by swelling, warmth, and instability in the joint. Treatment for torn cartilage is similar to treatment for a torn ligament (see page 316). A torn meniscus is often repaired using arthroscopy (see box on previous page).
Other Knee Disorders
Tendinitis (see page 306) can occur in the front of your knee below the patella (kneecap) or in the back of the knee at the popliteal tendon. As with ligament injury, tendinitis is treated with RICE (see page 65) and nonsteroidal anti- inﬂammatory medication such as aspirin or ibuprofen. Rehabilitative exercise programs can begin when the swelling is gone. Because corticosteroid injections can rupture knee tendons, they are rarely, and very carefully, given. Surgical repair of a severely ruptured tendon may be necessary.
Bursitis (see page 305) of the knee commonly occurs on the inside of the knee and on the front of the kneecap. Treatment is similar to that for the ligament and tendon injuries described above. Osteoarthritis (see page 308) is a common cause of pain and inﬂammation in the knees. In severe cases, surgery to replace the damaged knee joints (see Joint Replacement, page 310) may be necessary.
Other Bone and Joint Disorders
Here are some less common diseases and disorders that can affect the bones and joints:
• Paget’s disease. Also called osteitis deformans, this chronic disorder disturbs the normal process of bone formation. The disease is more common among men and among adults age 40 and older. The cause of the disease is unknown. With Paget’s disease, normal bone breaks down more rapidly than usual and is replaced by abnormal bone. The new, abnormal bone is larger but weaker than healthy bone. Paget’s disease usually affects the leg bones, upper arm bone, collarbone, and pelvis. Bone pain, deformity, and fractures are the most com- mon symptoms. A diagnosis of Paget’s disease is conﬁrmed with X rays and blood tests. Most cases do not require treatment other than painkillers such as aspirin and regular monitoring of the affected bones. In severe cases, treat- ment may include calcitonin or etidronate to relieve pain and to promote nat- ural bone formation. In some cases, surgery to correct the bone deformities may be necessary.
• Osteomalacia. This condition weakens the bones of adults through deminer- alization (excessive loss of calcium and phosphorus). Osteomalacia is caused
by vitamin D deﬁciency, which usually results from insufﬁcient vitamin D intake, limited exposure to sunlight, or inadequate absorption of vitamin D by the intestines. Kidney disease, certain metabolic disorders, and some medica- tions also can increase the risk of developing osteomalacia. Symptoms include bone pain, usually in the neck, ribs, hips, and legs; restricted mobility; and difﬁculty walking. Diagnosis is based on symptoms, X rays, and the results of blood tests. Treatment focuses on increasing vitamin D levels in the body. The doctor also may recommend calcium supplements. Any underlying cause of the disease also must be treated.
• Ankylosing spondylitis. Ankylosing spondylitis is a form of arthritis that pri- marily affects the spine, shoulders, hips, and knees. Ankylosing spondylitis frequently begins between ages 20 and 40 and is more likely to occur in men than in women. It appears to run in families. Symptoms include pain and stiff- ness (in the lower back, especially after resting), chest pain, loss of appetite, and redness and pain in the eye (due to inﬂammation of the iris). As the dis- ease progresses, it can be extremely painful and crippling. In severe cases, the vertebrae in the spine may fuse. Diagnosis is based on symptoms, blood tests, and X rays. There is no cure for ankylosing spondylitis. However, symptoms may be relieved with heat treatments, massage, and a supervised exercise pro- gram to strengthen the back muscles. The doctor also may prescribe non- steroidal anti-inﬂammatory drugs to reduce pain and stiffness.