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.
