Introduction
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Figure 1 - The hip joint |
The
hip joint is commonly called a “ball and socket”
joint. The “ball” of the hip joint, the femoral
head, rests within a “socket” called the
acetabulum (See Figure 1). The femoral head and
acetabulum are covered by a specialized surface,
articular cartilage, which allows smooth and
painless motion of the joint.
With hip injury or disease, articular cartilage
deteriorates and wears away. The joint surfaces
become rough and irregular resulting in pain and
stiffness. This is commonly known as “arthritis”
but it has many causes including developmental
dysplasia, osteonecrosis and trauma. The onset
of pain is gradual and, initially, it occurs
only after higher levels of physical activity.
Pain gradually increases and may also become
present at rest. Physical disabilities may
include a limp, muscle spasm, and decreased
range of motion with increasing stiffness.
Treatment options include reducing stress on the
hip, physical therapy, and medications.
Weight reduction is highly desirable, since one
pound weight loss equals three pounds in stress
reduction on the hip while walking. The use of a
cane or walking stick is also a very effective
means of reducing stress on the hip. Physical
therapy and exercises are directed at preserving
muscle strength and range of motion within the
limits of pain. Recommended medications include
anti-inflammatory agents. Selection of the
optimal treatment plan should be consistent with
the degree of pain, the amount of hip
disability, and the age of the patient. The
individual’s anticipated life span will also
influence the selection of treatment. In the
active adult, conservative treatment is
recommended whenever possible including
biological solutions as well as prosthetic
procedures.
Joint Preserving Solutions
Joint preserving solutions are those that
preserve your own living tissues. Unlike
prosthetic implants these alternatives can adapt
more effectively to the strains of everyday life
and, accordingly, they can be advantageous to
the younger, more active individual.
Traditional, stem-type total hip replacement (THR)
is one of the most successful surgical
procedures introduced. Howerver, the success
rate of cemented and cementless stem-type THR at
15-20 years in patients less than 50 years of
age has been disappointing with failure rates
ranging from 10% to 33% as reported in various
studies. It is also important to differentiate a
less than optimal outcome following THR versus
that of a joint preserving procedure. For
instance, a “poor” outcome following THR could
include either dislocation or loosening of the
prosthesis with loss of bone. On the other hand,
a “poor” outcome following joint preserving
surgery could include continued pain or the
eventual onset of osteoarthritis
of the hip. If either of these scenarios were to
occur following joint preserving surgery, then
you may need to take anti-inflammatory
medication and/or eventually consider hip
replacement surgery. However, the critical point
is that you have preserved and maintained your
entire hip joint thereby facilitating future
treatment if necessary.
Hip
Arthroscopy
Indications for a hip
scope:
Hip
pain resulting from tears of the acetabular
labrum or as a diagnostic tool.
Discussion:
The
acetabular labrum is a horseshoe-shaped
fibrocartilaginous structure attached to the
periphery of the acetabulum that adds depth to
the hip joint. It is a different type of
cartilage than that which “cushions” the hip
joint. Its function is to provide additional
stability to the hip when moving the hip to its
upper limit of motion.
The
labrum can tear suddenly as a result of a fall
or by moving the hip to its upper limits of
motion or it can tear gradually from repetitive
stresses. The patient may experience catching or
clicking associated with discomfort on the front
of the hip. Pain may worsen with long periods of
sitting. Only 1/3 of patients recall trauma to
the hip joint.
A
labral tear can often occur if the hip socket is
shallow or as a result of impingement. In this
condition, the labrum is trying to compensate
for insufficient bone covering the femoral head
and it is bearing the majority of the load. In
this type of “hip dysplasia”, repairing the
labral tear is not indicated as it will not
solve the underlying cause (i.e., shallow
socket) and an osteotomy needs to be considered.
It should be noted that pure labral tears with
no underlying hip malformation are rare in
comparison to other conditions that necessitate
hip reconstruction.
Diagnosis:
On
physical exam, a labral tear manifests itself
when the range of motion is more than normal and
there is pain either with hip flexion, internal
rotation and adduction or extension in external
rotation. General radiographs are initially
reviewed to rule out hip dysplasia followed by
an MRI with contrast injection (gadolinium
enhancement). The MRI cannot detect all labral
tears and, in fact, a “false-negative” result
occurs in about 10% of cases.
Treatment and
Post-Operative Recovery:
If
the MRI is positive and the hip joint is
properly formed then a hip arthroscopy is the
procedure of choice. A hip arthroscopy can
address the labral tear resulting in pain relief
and a return to near normal function. Some
patients (5%) do not experience full pain relief
because of damage to the cartilage lining. The
procedure is performed on an outpatient basis.
The recovery is relatively simple in that the
patient is on crutches for 1-2 weeks and they
are able to bear full weight on the operated
leg. 70%-90% of patients with labral tears who
undergo hip arthroscopy report good to excellent
results at three years.
If
the MRI is negative yet hip pain persists, the
hip is injected with a local anesthetic (marcaine)
to confirm that the hip is the source of the
pain. If the pain relief is complete, then an
arthroscopy is still indicated since the MRI may
not have detected the tear.
Ganz or “Bernese”
Periacetabular Osteotomy (PAO)
Indications for treatment:
Hip
dysplasia and/or a retroverted acetabulum
Discussion:
The
word dysplasia refers to malformation or lack of
full development. Some patients develop this
condition from birth or in early childhood and
surgery is performed at that time. In others,
the hip becomes painful in early adulthood or
they have been treating the painful hip as a
groin injury for several years with either
physical therapy or anti-inflammatory
medication. Symptoms are often unrecognized as
hip dysplasia as patients will complain of
buttock pain or pain over the lateral aspect of
their hip going down the side of the thigh. Many
patients ask the question: “Why has my hip
become painful only now?” The best answer is
that cartilage does have the capacity to
function within an adverse environment for a
period of time without the patient experiencing
pain. However, at some point just as with tread
on a tire, the cartilage begins to wear out and
treatment becomes necessary.
Diagnosis:
Physical findings are similar to labral tears.
Xrays will typically reveal the obvious
malformation (See Figure 2). After a careful
radiographic review, the location and severity
of the dysplasia is established and this will
dictate the most appropriate joint preserving
Treatment and
Post-Operative Recovery:
The
role of pelvic osteotomies for the treatment of
hip dysplasia has a long history in orthopedics.
Until the advent of the PAO in the mid-1980’s,
most pelvic osteotomies did not result in
reproducible or sufficient corrections. Further,
they modified the normal anatomy of the pelvis
and often required casting. Highly trained
surgeons are now routinely performing the PAO
with good results. A periacetabular osteotomy
involves dislodging the hip socket from its bony
bed in the pelvis without distorting the normal
pelvic anatomy. The socket is then reoriented in
the proper position to relieve hip pain and
prevent osteoarthritis. This is verified by
taking an x-ray during the surgery. When the
socket has the correct orientation, it is fixed
with screws. These screws can be removed at a
later date if they irritate the skin. The
patient ambulates the day following surgery
using crutches and under the supervision of a
physical therapist. Most patients are discharged
four days after the surgery. You will use
crutches for eight weeks (i.e., restricted
weight bearing) at which time an x-ray will be
taken. Physical therapy will be prescribed at
that time and you can apply full weight on the
operated leg. After 4 to 6 weeks of physical
therapy, most patients return to regular
activities.
Femoral
Head-Neck Chondro-osteoplasty
Indications for use:
Femoro-Acetabular
Impingement/late sequalae of childhood hip
problems including Legg-Calvé-Perthes and
slipped capital femoral epiphysis. Discussion:
Most of the focus on hip malformations has been
on the socket although it has long been
recognized that abnormalities of the femoral
head and neck or “ball” of the hip joint can
lead to early osteoarthritis. The head and neck
relationship is critical in avoiding an
impingement at the rim of the socket. If that
relationship has been disrupted (i.e., a wide
neck or lack of offset between the two), then
this will create a “cam effect” and initially
damage the labrum anteriorly (See Figure 4). It
can also create a shear force on the cartilage
lining leading to its degeneration, in other
words, hip arthritis. The onset of symptoms and
the clinical presentations will be very similar
to those for acetabular or “socket” dysplasia.
Patients will have difficulty in maintaining a
high activity level initially and over time the
pain will evolve to a constant, dull ache in the
hip region worsening after long periods of
sitting. Until recently, there was no safe way
to gain access to the femoral head and neck
without interrupting its blood supply causing
avascular necrosis (i.e. death of part of the
femoral head). The surgical approach known as
surgical dislocation was introduced to permit
easy access to the hip joint without disrupting
the blood supply to
the femoral head and neck.
Treatment and
Post-Operative Recovery:
Chondro-Osteoplasty with a surgical dislocation
approach involves releasing a medallion of bone
from the greater trochanter permitting access to
the head and neck by dislodging the hip from the
socket. Once the desired correction of the
deformity is completed, the medallion of bone is
reattached
with screws. At six weeks post-surgery, the
patient can bear full weight and physical
therapy is then prescribed for 4-6 weeks.
Patients typically experience immediate pain
relief and they can gradually resume normal
activities at eight to twelve weeks following
surgery.
Joint replacement options:
For
most people, the best surgical solution after
the joint surface shows signs of arthritis is a
total hip replacement
