Anterior
cruciate ligament (ACL).
A front-crossing
ligament attaching the femur
to the tibia through the knee;
this ligament keeps the knee
from hyperextension or being
displaced back from the femur.
The ACL is a rather large ligament
that can withstand 500 lb (227
kg) of pressure. If it is torn
or becomes detached, it remains
that way and surgery is indicated.
In the most severe cases, a
graft to the ligament is necessary
to reattach it to the bone.
The surgery can use tissue from
the patient, called an autograft,
or from a cadaver, called an
allograft. The patella tendon,
which connects the patella to
the tibia, is the most commonly
used autograft. ACL reconstructive
surgery involves drilling a
tunnel into the tibia and the
femur. The graft is then pushed
through the tunnels and secured
by stapling or sutures. |
|
Knee
arthroscopic surgery
Definition
Knee arthroscopic
surgery is a procedure performed through
small incisions in the skin to repair
injuries to tissues such as ligaments,
cartilage, or bone within the knee
joint area. The surgery is conducted
with the aid of an arthroscope, which
is a very small instrument guided
by a lighted scope attached to a television
monitor. Other instruments are inserted
through three incisions around the
knee. Arthroscopic surgeries range
from minor procedures such as flushing
or smoothing out bone surfaces or
tissue fragments (lavage and debridement)
associated with osteoarthritis, to
the realignment of a dislocated knee
and ligament grafting surgeries. The
range of surgeries represents very
different procedures, risks, and aftercare
requirements.
While
the clear advantages of arthrocopic
surgery lie in surgery with less anesthetic,
less cutting, and less recovery time,
this surgery nonetheless requires
a very thorough examination of the
causes of knee injury or pain prior
to a decision for surgery.
Purpose
There are many
procedures that currently fall under
the general surgical category of knee
arthroscopy. They fall into roughly
two groups—acute injuries that destabilize
the knee, and pain management for
floating or displaced cartilage and
rough bone. Acute injuries are usually
the result of traumatic injury to
the knee tissues such as ligaments
and cartilage through accidents, sports
movements, and some overuse causes.
Acute injuries involve damage to the
mechanical features, including ligaments
and patella of the knee. These injuries
can result in knee instability, severe
knee dislocations, and complete lack
of knee mobility. Ligament, tendon,
and patella placements are key elements
of the surgery. The type of treatment
for acute injuries depends in large
part on a strict grading system that
rates the injury. For instance, grades
I and II call for rest, support by
crutches or leg brace, pain management,
and rehabilitation. Grades III and
IV indicate the need for surgery.
Acute injuries to the four stabilizing
ligaments of the knee joint—the anterior
cruciate ligament (ACL), the posterior
cruciate ligament (PCL), the medial
collateral ligament (MCL), and the
lateral collateral ligament (LCL)—as
well as to the "tracking,"
or seating of the patella, can be
highly debilitating.
Treatment
of these acute injuries include such
common surgeries as:
- Repairs
of a torn ligament or reconstruction
of the ligament.
- Release
of a malaligned kneecap. This involves
tendon surgery to release and fit
the patella better into its groove.
- Grafts
to ligaments to support smoother
tracking of the knee with the femur.
Pain
management surgeries, on the other
hand, are used to relieve severe discomfort
of the knee due to osteoarthritis
conditions. These treatments aim at
relieving pain and instability caused
by more chronic, "wear and tear"
kinds of conditions and involve minor
and more optional surgical procedures
to treat cartilage and bone surfaces.
These include arthroscopic techniques
to remove detached or obtruding pieces
of cartilage in the joint space such
as the meniscus (a fibrous cushion
for the patella), to smooth aged,
rough surface bone, or to remove parts
of the lining of the joint that are
inflamed.
Treatment
distinctions between arthroscopic
surgery for acute injuries and those
for pain management are important
and should be kept in mind. They have
implications for the necessity for
surgery, risks of surgery, complications,
aftercare, and expectations for improvement.
Arthroscopic surgery for acute injuries
is less controversial because clear
dysfunction and/or severe instability
are measurable indications for surgery
and easily identifiable. Surgery indications
for pain management are largely for
chronic damage and for the milder
grades or stages of acute injuries
(severity Grade I and II). These are
controversial due to the existence
of pain management and rehabilitation
alternatives. Arthroscopic surgery
for pain management is currently under
debate.
Demographics
More
than five and a half million people
visit orthopedic surgeons each year
because of knee problems. Over 600,000
arthroscopic surgeries are performed
annually; 85% of them are for knee
surgery. One very common knee injury
is a torn anterior cruciate ligament
(ACL) that often occurs in athletic
activity. The most common source of
ACL injury is skiing. Approximately
250,000 people in the United States
sustain a torn or ruptured ACL each
year. Research indicates that ACL
injuries are on the rise in the United
States due to the increase in sport
activity.
The
incidence of ACL injuries in women
is two to eight times greater than
in men. While the exact causes are
not clear, differences in anatomy,
strength, or conditioning are thought
to play major roles. Women also seem
to be more prone to patella-femoral
syndrome (PFS), which is the inability
of the patella to track smoothly with
the femur. PFS is due primarily to
development of tendons that influence
the ways in which the knee tracks
in movement. It can also be due to
misalignments to other parts of the
lower body like foot pronation. Other
ligament surgeries can be caused by
injury or overuse.
Knee
dislocations are a focus of recent
research because of their increasing
frequency. Incidences range from 0.001%
to 0.013% of all patients evaluated
for orthopedic injuries. Many of these
injuries heal without treatment and
go undetected. Many people with multiple
traumas in accidents have knee dislocations
that go undiagnosed. Knee dislocations
are of special concern, especially
in traumatic injury, because their
early diagnosis is required if surgery
is to be effective. Knee dislocations
in the morbidly obese individuals
often occur spontaneously and may
be associated with artery injury.
This surgery involves complications
related to the obesity. Finally, knee
dislocations have been reported to
occur in up to 6% of trampoline-associated
accidents.
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