Two common sports-related knee injuries, often associated with each
other, are meniscus tears and stretched or torn cruxiate ligaments.
Aikidoka are at risk for these due to the torquing involved in many of
Quick and dirty review of anatomy for beginners
The knee is a complex joint that needs to move in many directions under
weight-bearing loads. The bottom of the thighbone (femur) meets the top
of the tibia, which is the larger and inner (medial) of our two lower
leg bones (the other being the fibula, which sort of hangs out snuggled
up to its larger sibling). Floating in front of them is an odd shield of
bone, the kneecap (patella).
For the bones of a joint to stay in place relative to each other, and
to keep us from collapsing in a heap, we need some support structures
(connective tissue). The muscles of the leg are attached to the bones,
so they can make them move, by tendons (I think of tendons as the
strings on marionettes: by holding things in connection, they translate
movement here into movement there). The bones themselves are connected
to each other by ligaments (I think of ligaments as strapping or
bindings). Finally, where bones meet, they need to be cushioned. There
are, in some parts of the body, little separate sacs called bursae
(think of the cells of a piece of bubble wrap, but with a fluid gel
inside instead of air); the knee has these. And at their ends, the bones
themselves have a layer of cartilage to absorb the wear and tear of
daily life's movement-with-weight-bearing (quick, another analogy...ok,
the little plastic gliders you tap onto the bottoms of table and chair
legs; heck they even LOOK like cartilage!).
The bottom of the femur and the top of the tibia are indeed
cartilage-clad. However, since the femur ends in two round knobs, and
the top of the tibia is pretty flat, its not a great match and something
extra is needed. That's the role of the medial (inner) meniscus and the
lateral (outer) meniscus, a pair of horseshoe shaped cushioning
cartilages that live between the femur and the tibia. A meniscus can be
torn as the result of a sudden torquing movement, or as a result of
There are large ligaments on the outsides of the femur and tibia that
look and act very much as straps holding them together. The cruxiate
ligaments provide extra support deep within the knee joint. They are
paired, an anterior (front) cruxiate ligament and a posterior (rear)
cruxiate ligament; they are called cruxiate because (ta-da!) they cross
each other to form an "x" in between the femur and tibia. Like any
ligaments, they are subject to either stretching minor sprain) or
outright tearing. For some reason, at least anecdotally, aikidoka seem
more prone to injury of the anterior cruxiate ligament (ACL)
What if my knee is injured?
The immediate first aid is the same as for any soft tissue injury:
RICE. If your leg injury causes a feeling of instability at the knee, it
may indicate ligament damage. A meniscus tear is sometimes accompanied
by swelling, catching, and a "clunk" sound. A physical exam by a
physician skilled with emergency, injury or sports medicine can assess
overall joint function, tendon integrity, and joint stability, but will
probably not give a 100% positive diagnosis. A "regular" x-ray will not
show soft tissue damage. An MRI will (of course, like any test, it is
not 100% perfect either).
If your doctor or insurer balks at doing an MRI, how much should you
fuss? Well, if you go in for treatment, and have been ruled out for a
broken bone by exam or x-ray but you can't really walk, I'd pretty much
insist on getting some answers right away: It likely won't be an MRI on
the spot, but either an appointment for one or an appointment asap with
whomever can authorize one for you. Take a deep breath and resolve to be
willing to get on the phone and be pleasantly persistent in order to get
what you need.
If, on the other hand, the physician doesn't think that you have
meniscus or ligament damage, and if you have decent weight-bearing
ability and minimal swelling and pain, I might consider holding off for
a couple of weeks to see if this is something that might heal with
"tincture of time" (for instance, a muscle injury that might show
improvement within a week or 2 and be nicely healed in a couple of
months). However, that time must be spent truly promoting healing: RICE,
no activities that put you at risk for re-injury, etc. If there is not
significant improvement, then I'd do whatever it takes to get an MRI and
a consult with a qualified sports medicine physician. You only have one
body and two knees, and no matter how compliant a patient you are,
cartilage and ligament tears will not self-repair!
A word about braces: The over-the-counter elastic-based supports may
provide a nice snug feeling and add some warming to the joint, and they
are very good at providing the "C" (compression) part of RICE. They
cannot actually give support to an unstable joint. Do not be lulled into
a false sense of security and start training with one thinking it will
protect you. It won't.
Having said that, there ARE custom-fitted braces available by
prescription that will provide some stability. Ask if your benefits
coverage includes durable medical equipment, and if your provider will
A little bit about knee repairs, based on a review of articles and a
long chat with the doctor...
Arthroscopy is one of those "band-aid" same day procedures. It can be
done under a local, with or without (yeah, right...) sedation, or with a
spinal anaesthetic, or if you are really nuts, under a general
anaesthetic. What do they do once they are in there?....It depends.
Since the MRI is not 100% definitive, nobody really knows what's going
on until they get in there to look.
A meniscus tear can be handled in a couple of ways. You can opt not to
treat it. Frankly, I don't think this is a good idea. It will result in
altered body mechanics in the knee joint, which will cause the meniscus
to be further ground away; when its gone, the only place for wear and
tear is the cartilage at the end of the bones, when that's gone...well,
you get the idea.
The damaged parts can be removed (partial meniscectomy) or, if the
whole thing is in pieces, the meniscus can be removed altogether (total
meniscectomy). The good side: minimal recovery time (some people go back
to work in a couple of days). The bad side: Cartilage once lost is gone.
Some tears, depending on where/how, are repairable, most often by
suturing. The good side: a repair that hopefully will hold up with time.
The bad side: longer recovery time than with scraping/removal (I was
told it could be a couple of weeks; your mileage may vary...). For
younger, more active people, repair is definitely considered preferable
While they are in there, they can look at the cruxiate ligaments and a
decision can be made regarding what to do. If the ligament is not torn,
but is stretched, there is a fairly new procedure called thermal
shrinking. Heat is applied to disrupt hydrogen bonds and shrink the
collagen fibers; it requires the right balance of heat and time, and
there are a couple of ways of doing it (laser and radiofrequency). From
a review of articles, it appears to be effective, but the effects are
variable and not predictable. It will definitely cause a short term
weakening of the tissues, during which time they can actually be
stretched further (hence a few weeks of bracing and non-weight-bearing
followed by rehab).
What about repairing a torn ligament?
Oy. Now we're talking the big deal, major rehab process. The ligament
has to be replaced with something that will attach to the femur, attach
to the tibia, have some give but not too much, and withstand all kinds
of forces from all kinds of directions (note that most objects in nature
fall into one of two categories: stretch-instead-of-breaking versus
break-instead-of-stretching. We, of course, want ligaments that just
hold tight no matter what darn fool thing we ask of them).
One way to form a new ligament is to take a tendon from another part of
your own leg (autograft). Some doctors like to use patellar tendons and
some use hamstrings tendons. More recently some have been doing tendon
transplants from folks who don't need them anymore (allograft). All
three have their own risks and benefits.
The big advantage of your own tissue is, well, it's you. Your body will
accept it easily. Another advantage is that the autograft tendons seem
to hold up longer without stretching. However there is more pain and a
greater risk of infection because of having to essentially do two
surgeries. The rehab process is harder and takes longer: first, you have
a donor site that has been cut, disrupted, and then put back together
and now has to heal; second, you can't remove a tendon without some
alteration in structure and function of the affected part.
The allograft method is newer and shows promise in that it is a shorter
surgery, with less pain, a lower infection rate, and a shorter rehab
time. Anytime one takes another's body parts, there is a risk of
infection (AIDS, hepatitis) and rejection. Current screening tests
appear to be effective for identifying disease-carrying tissue; no cases
of transmission have been identified. Rejection of a tendon is very
rare, as compared to of a heart or kidney, because there are not a lot
of antigenic proteins on connective tissue, but it can happen. If it
does, the graft has to be removed. A key disadvantage is that the
allograft seems to be a somewhat looser and less strong graft than the
I don't think there is any one "right" choice. These are judgement
calls; each patient needs to review the literature and talk with his/her
surgeon. If you talk with friends or check out the online chat rooms or
bulletin boards, beware of making a final decision based on one or two
compelling anecdotes. What I've learned in 20 years as a nurse is that
for ANY given medical procedure there will be both horror stories and
miracle stories. If I needed a repair, I'd probably opt for the
allograft, trading off a potentially weaker graft (ok, so I wear a brace
in the dojo from now on...) for not having to be so worried about
problems with the donor site.