Oddities in knee alignment

Posted on February 24, 2014

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From an upcoming, much longer post, detailing my second visit to The Washington University in St. Louis. Where I took a course by Shirley Sahrmann and the physical therapy department. You can read about my first visit here

Shirley made some remarks on how past meniscal issues can affect current knee alignment.

When it comes to the meniscus, medial issues are more common than lateral issues.

Medial meniscus on left; lateral meniscus on right. (Top view.)

Medial meniscus on left; lateral meniscus on right. (Right knee, top view.)

Adapted from http://www.sportsorthopaedicspecialist.co.uk

Right knee, anterior view. (Adapted from http://www.sportsorthopaedicspecialist.co.uk)

When you’re dealing with an older demographic, if they have had a meniscus issue, they probably had a tear which was left alone, or a partial menisectomy. Within that, it was probably on the medial side. Mensical repairs are a newer procedure, and most older people had their meniscal surgery done decades ago. Thus, it was probably a partial menisectomy. (This is worth knowing because most clients won’t remember or know what specifically was done to their knee.)

What you may see with a person like this, especially as they age, is their knee alignment changes to reflect their meniscal changes. Because the medial side has lessened or is gone, the femoral condyles don’t sit on the meniscus like they used to. The person may shift to a varus alignment.

Knee alignments

To illustrate this, I’m going to show an example of someone who had their entire medial meniscus taken out. This is often not the case, but it helps for clarity. Because this is tough to visualize, at least it is for me, try using a cup with a ledge to help. One side of the ledge is the intact meniscus, the other is the excised:

Front Medial Meniscus Not Cut with lines

You can see how things will change:

Front Medial Meniscus Cut with arrow

Lateral meniscus left in tact; medial meniscus has been removed.

Close up of normal alignment (right leg, anterior view):

Close Up Normal Knee Alignment with lines

Close up of varus alignment:

Close Up Varus with lines

Note the similarities:

Close up Normal to VARUS meniscus GIF

Normal to VARUS meniscus

This can go the other way too: Lateral meniscus excision => Valgus alignment. In fact, I have a client with this deformity. Can you recognize which knee had the lateral meniscus partially excised?

Sharon Knee alignment close up

The right:

Sharon Knee alignment close up with lines

Using the cup again:

Front before VALGUS cup with lines

Front Cup to VALGUS with lines

There’s that sharper angle at the knee joint now:

Sharon Knee alignment close up with lines and arrow

Front Cup to VALGUS with lines and arrow

This is important because you gain an increased understanding of why someone looks and moves the way they do. While I focus with Sharon (pictured above) on not letting her knee cave in, we both understand not to expect it to look like her other knee. We also understand her knee having this now structural issue, predisposes her to not handle certain activities well. Like the racquetball she loves to play. Having a knee with an increased valgus alignment makes her more susceptible for it to collapse inward during activity, which is often how knee injuries happen.

This is the conundrum with many meniscal procedures. While they may give you pain relief in the short term, helping you get back to the activity which likely caused your injury -racquetball for instance- the meniscal procedure could very well make it more likely you injure your knee again, like while playing racquetball.

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