Dodge Safe #10: Protect Your Knees!

Posted on February 10, 2014 at 7:07 pm |

The gamesmanship of dodgeball has evolved over the past several seasons. In both upper and lower tiers, players are looking to make the big catch rather than throwing or dodging. As a result, more and more players have adopted a “drop down” method in their catching, in which they drop low on to their knees so that they are level with the height of an incoming ball. This method of catching often reaps huge rewards, but also comes with sacrificing your knees, especially for those who don’t wear knee pads.

This article will discuss the complications that can arise with repetitive knee trauma. Keep in mind that wearing knee pads only decreases the risk of these conditions and does not completely eliminate them.

Bruised Knees

A bruised and/or swollen knee, also known as a patellar contusion, is an injury to the soft tissue, in which capillaries and small veins are damaged by trauma, allowing blood to seep into the surrounding tissues (Harrison’s Principles of Internal Medicine, 2008). Everyone has bruised their knee or some other joint at least once in their lifetime but it’s an injury nonetheless. It is relatively easy to treat a contusion, which often does not require any intervention to resolve other than time. Treatment of a contusion typically involves application of ice packs for 15 minutes every 3 to 4 hours for the first 2 to 3 days or until pain or swelling decreases (McKesson Corporation, 2010).

Bone Bruise

If impact or trauma is severe enough, bruising can involve the bone, in which very small breaks occur to the outer layer of the bone (Sheldon, 2011), a stage preceding an actual fracture (, n.d.). For the knees, this means damage to the femur (the thigh bone), tibia (the shin bone), or more commonly the patella (the kneecap).

Figure A. Bone bruise of the femur or thigh bone. Adapted

Figure B. Bone bruise of the femur as indicated in a MRI. Adapted from

Like most bruises, a bone bruise is characterized by pain and swelling, but in the case of an actual injury, the pain may be more severe and may last longer than soft tissue bruising. Swelling from a bone bruise may also spread to the joint. Bone bruises take a long time to recover, requiring 5-12 months before the outer layer of the bone is completely healed (Punwar et al., n.d.).

Chondromalacia Patella

Chondromalacia Patella (CMP) is an injury to the cartilage that covers the back of the kneecap. In dodgeball, this type of kneecap injury can occur when the front of the knee suffers an impact, such as falling directly on to it. The sudden impact between kneecap and the underlying thigh bone can cause small tears or roughening in the cartilage at the back of the kneecap (Sportsinjuryclinic, n.d.).

Figure C. Cartilage damage at the back of the kneecap. Adapted from

With CMP, you may experience swelling and feel pain over and around the kneecap. Pain is often worse when walking downstairs or after sitting for long periods of time. You may also feel a grinding or clicking when bending and straightening the knee. This grinding and clicking is called crepitus and happens when the back of the kneecap rubs against the knee joint behind it (, n.d.). Inflammation occurs each time the back of the kneecap grinds against the underlying joint, and if left untreated can lead to other chronic knee problems.

Protect Your Knees!

If you tend to drop down and slide around on your knees when you play dodgeball, I strongly encourage you to wear kneepads if you don’t do so already. You may still suffer from the injuries described above but protective knee pads help lessen the chances of these occurrences.

Also, if you are experiencing symptoms of bone bruises and/or chondromalacia patella, it is best to seek medical attention before the injury worsens.

Carolyn Tam is a registered physiotherapist currently working in the Lower Mainland. She completed her Master of Physical Therapy degree at the University of British Columbia after graduating from UBC with a Bachelor of Human Kinetics.


Harrison’s Principles of Internal Medicine. 17th ed. (2008). United States: McGraw-Hill Professional.

McKesson Corporation and/or its affiliates. (2010). Patella Contusion (Bruised Knee). Retrieved on February 8, 2014 from (n.d.) Bone Bruise. Retrieved on February 8, 2014 from

Punwar, S., Hall-Craggs, M., and Haddad, F., (n.d.). Bone Bruises. Retrieved on February 8, 2014 from

Sheldon, Andrew. (2011). Physical Therapy for a Bruised Knee Bone. Retrieved on February 8, 2014 from (n.d.) Chondromalacia Patella. Retrieved on February 8, 2014 from

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