Hip Arthritis
 The arthritic hip is a significant problem for many people; it may
arise as a result of wear and tear (normal or accelerated), caused by:
rheumatoid arthritis, trauma, or joint collapse caused by a fault in blood
supply to the femoral head (ball of the joint). The hip is a ball and
socket joint which is very stable and resistant to wear. As a result of
this resistance to wear, hip joint replacement is more common with advancing
age. In some cases however, the joint may be subject to early or
accelerated wear which necessitates earlier replacement surgery. Because
the replacement has a finite life, other management strategies are employed to
delay surgery,
(unless this is not an option) until the patient is at least 60
years of age.
The hip may also need replacement in some cases of fracture,
although the prosthesis differs depending on patient age and bone quality as
well as general health. While the baseline status of the of the patient
and the reason for replacement are variables, hip replacement is nearly always
successful, and has an excellent outcome with restoration of mobility and
walking tolerance without pain.
Arthritis
Joint surfaces are covered with a smooth layer of cartilage. This
cartilage absorbs shock, and together with the normal joint lubrication provided
by the joint lining, provides a smooth low friction surface. The surface
cartilage has a limited capacity to heal itself. As it wears away, bone is
exposed. Bone surfaces in contact cause pain while cartilage has no
sensation. The inflammation caused by the debris of joint wear causes pain
and stiffness, and new bone reaction leading to loss of motion.
Symptoms
Symptom onset is generally subtle. Walking tolerance usually slowly diminishes over many years to the point where only one or two blocks are
possible without resting. Pain is increased by activity and cold damp weather. Anti-inflammatory medications (aspirin related) are the main-stay
of conservative treatment along with alteration of daily activities.
Swimming and bicycling are generally less painful than walking or running
sports. The arthritic hip loses range of motion slowly, especially
rotation.
Often the hip in need of replacement has become functionally a
simple, painful hinge joint. Climbing or descending stairs or arising from
a chair is especially painful. This is because the loads across the
painful joint are multiplied by these activities. As a result, activities
of daily living become laborious.
Diagnosis
Diagnosis is usually straightforward. Arthritis is usually easily seen
on plain X-ray films, and hip motion is generally limited and painful. The pain
is often in the groin or radiates into the thigh or even to the knee.
Sciatica or nerve related pain from the back may coexist, or be confused with
the pain of hip arthritis. In cases where the x-ray and physical exam do
not match the pain complaints, MRI, bone scan, or joint injection test may be
indicated to localize the source and cause of pain.
Surgery
Replacement of the worn joint is usually performed on both the ball and cup
except with the presence of fracture. Generally the cup is replaced with a
metal shell which is rough on its outer surface and encourages bone ingrowth.
The femoral stem is generally cemented into the marrow canal of the femoral
shaft. Pressed onto this, a metal ball articulates with a hard plastic liner locked into the metal cup. This forms a stable joint and my be walked upon
immediately. Non-cemented prostheses have been used in recent years in an
attempt to increase the longevity of implants. These are only used in the
younger more active individual. They may be associated with lingering
thigh discomfort, probably related to micro-motion of the femoral stem.
The Total Hip Replacement Candidate is ideally greater than 60 years of age and
in generally good health. There should be no history of prior hip
infection. In addition, any chronic or recurrent infection elsewhere may
lead to late prosthetic infection. Because of this, dental abscesses
should be thoroughly treated. A patient with recurrent urinary tract
infection secondary to retained kidney stones, urethral strictures, or other
genitourinary problems should have urology evaluation prior to total joint
replacement. Antibiotics are used after surgery, during dental work, or
during colonoscopy to minimize the risk of late infection.
Blood Transfusion
Transfusion of two units of blood is required in most cases. We
encourage patients to donate their own blood prior to surgery to minimize the
risk of disease transmission. A week between each donated unit and before
surgery allows time for the blood count to normalize. In certain instances
where religious belief prevents blood transfusion, hip replacement may be done without donating or receiving blood. Erythropoietin (a normal hormone
which stimulates blood production) may be given preoperatively to allow surgery
more safely without transfusion. Surgery without transfusion, may
represent a higher risk during and after surgery.
Hospitalization
Patients are admitted the day of surgery and stay generally from 4 to seven
days. Depending on home support and preoperative fitness, patients may
return home with home physical therapy and a home health aid, or receive
additional intensive physical therapy at a rehabilitation center. This
decision is generally made during hospitalization when it becomes clear what
functional needs will be required before discharge, and depending on insurance
coverage.
Complications
The most serious complication after total joint replacement is infection.
This occurs in less than 0.5% of hip replacements, but the incidence is
minimized with prophylactic antibiotics. If infection occurs, removal of the
prosthesis at least temporarily is usually necessary. Deep venous
thrombosis (clot) may also occur. This is minimized by the use of anticoagulant
medication, which is started in the preoperative period and is continued for two
weeks after surgery. Safe control of anticoagulation requires weekly blood
tests and necessary adjustment. Dislocation occasionally occurs. This is
minimized by careful prosthetic positioning and maintenance of safe hip
positions for two months after surgery. Leg length discrepancy may occur because
of inability to restore normal length, or in occasional instances where hip
stability precludes restoration of equal length. This may be normalized with a
shoe lift if necessary. In nearly all instances excellent results after Total
Hip Replacement allow a return to high level function without pain. |
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