The challenges of anterior knee pain
 By
Michael Gordon, MD, Milwaukee Orthopaedic Group, Ltd. Orthopedic
Surgery, Sports Medicine Fellowship
A common site of discomfort for runners is pain in the front of the
knee. Annoying in nature, this aching can be attributed to several
possible sources, some of which are easily correctable.
Generally, “anterior knee pain” refers to symptoms that originate in
the knee extensor mechanism. Quite simply, this is the part of the leg
that allows you to straighten out your knee. It begins in the thigh with
your quadriceps (large muscle bulk), which connects to the kneecap by
the quadriceps tendon. The next structure in the chain is the kneecap
(patella), and finally, the patellar tendon connects to the shinbone
(tibia). An injury to any of these structures can lead to pain that is
felt in the front of the knee.
The most common source of pain that I see in runners is called
chondromalacia patellae, a softening of the cartilage on the backside of
the kneecap. This particular cartilage is the thickest in the body
helping the kneecap glide along the front and end of the thighbone. When
it softens, it doesn't dissipate the impact of walking/running, which
can then lead to pain in the kneecap.
The obvious question (and $64,000 one) is what makes this soften? The
answer is fairly complex and something that's not quite understood
completely. We do know that the kneecap is exposed to some of the
highest “sheer stress” levels in the body – every pound we weigh leads
to about 4 pounds of stress across this cartilage. We also know that for
articular cartilage to work well, it needs to evenly distribute stress;
any mal-alignment or small defect in the cartilage can cause significant
pain.
Treatment for chondromalacia patellae focuses on fixing any
underlying mal-alignment and then trying to create a more supportive
environment for the cartilage. When diagnosing knee problems, I start
with the feet to make sure that the ankles and arches are doing what
they are supposed to do. Then, it's on to the hips to be sure that there
is good strength and balance across these joints. Next, I work on
correcting any poor tracking of the kneecap along the front of the knee
with either stretching exercises or in rare cases, surgery.
Just as critical for pain reduction are muscle rebalancing between
the quadriceps and hamstrings, as well as hamstring stretching. Finally,
I encourage my patients to consider glucosamine sulfate and chondroitin
sulfate as potential cartilage supporting supplements. There are several
studies that have reported encouraging benefits, but more importantly,
these supplements have shown minimal side effects. However, before
starting any new medical regiment, please discuss it with your doctor to
rule out any medicine interactions and contraindications.
Another source of anterior knee pain is patellar or quadriceps
tendonitis. This is an inflammation of the main tendons that connect the
kneecap to the shinbone and thigh muscle. Oftentimes, these tendons
become tender to the touch and are accompanied by local swelling and
even a sense of “squeaking” as you rub over them. Treatment is based on
stretching, local massage, rest, and anti-inflammatory medications. To
help prevent a reoccurrence, it's important to determine what led to the
development of this problem (i.e. poor training, “too much, too soon”,
inappropriate shoe wear, tight muscles, etc.)
Other less common sources of anterior knee pain include hip disease,
quadriceps strain and inner knee joint pathology. Surprisingly, in very
rare cases, hip arthritis or other problems can imitate knee pain. The
discomfort caused by these conditions is referred down the front of the
thigh, distributed using one of the major nerves of the leg. In these
cases, anterior knee pain can oftentimes be ruled out with simple log
rolling of the hip and/or an x-ray of that joint.
Quad, or thigh muscle strains, can also refer pain straight down the
front of the knee. Generally, this condition can be fairly easily
diagnosed with simple palpation along the muscle.
Finally, there are other issues within the knee that can lead to pain
along the front of the joint. These include articular cartilage problems
of the trochlea (the groove on the end of the thighbone in which the
patella rides), a plica (a shelf of tissue that runs along the front
inside portion of the knee), or an anterior tear in one of the menisci.
All of these conditions can be nagging problems and oftentimes can
benefit from surgery.
Anterior knee pain can be challenging, particularly for runners. It's
occurrence is usually due to relatively easily correctable problems
“above and below” the knee itself. If you start feeling twinges of pain
in the front of your knee or have increasing difficulty with stairs or
sitting still for any prolonged period of time, I encourage you to have
your knee examined. Early detection and correction of these problems can
help to keep a relatively simple condition from becoming much more
complex and difficult to treat.
Dr. Michael Gordon, of the Milwaukee Orthopaedic Group, Ltd. is an
orthopedic surgeon with a fellowship in sports medicine. For questions,
you can reach Dr. Gordon at 414-276-6000.
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