I had an entertaining conversation the other day with one of my long-time trainers and good friends, Justin Coffeen. He and I have worked together for the last 3 years and every time we talk I get a new idea. After we discussed the inflammation response of the lower body, including looks at the human body response to injury in the soft tissues, I decided to address an issue we run across all the time. We talked about compensations, the way the body adjusts to specific injuries like ankle injuries, shin splints (a personal favorite), and ‘blown knees.’ I’ll touch on the anterior compartment of the lower leg some other time, (shin splints). For this discussion, we’ll take a brief look at the structure of the knee, how it works, why you get pain, and how your body responds as a compensatory reflex.
You may suffer from one of these issues, a friend, a relative, trust me, someone you know has knee problems. As a forewarning, this article dives deep into specifics, more than my normal anecdotes, so don’t fear, I won’t do this all the time, just occasionally. I’m going to go off on an anatomy and physiology lesson in a second, but a basic understanding of the use of the knee will help understanding exercise presciption, why you hurt, and how to prevent or rehabilitate properly. I would recommend that ALL knee joint injuries be viewed with an understanding that it is usually a result of microtrauma (lots
Uneven tire wear
of use) injuries that are in conjunction with hip, spine and ankle compensations. If your knee hurts on a regular basis, have a trained professional look at the surrounding joints to identify the true issues. The most common cause of these types of knee injuries is hip mobility problems. Your hips are likely an issue. Your feet and ankles are probably also involved. Think of knee injuries like a balding tire on a car. I once did 2 years time in a tire shop, you would be surprised at how many people would replace tires instead of fixing the chassis and then replacing tires. They always had to come back…Anyway, If a tire gets bald on one side only, fix the chassis, then change the tires. If your tire pops (nail, something in the road), fix the tire, but still look at how a new tire affects the other tires and in-turn, the chassis. I’ve met a lot of ‘carve-happy’ doctors who want to ‘clean out’ a joint without identifying its root cause. Okay, off the soap box and back into the classroom…
Knee Joint
First, lets look at the specific design of the knee, its operations manual, if you will. The knee is comprised of 4 bones, the femur (your thigh), the tibia or lower segment, the patella (that nobby thing on the top), and the fibula, which rotates around and under the tibia and is technically not an articulating surface in the knee joint, but for purposes of understanding its support role, I’ll include it. The joint structure itself is designed specifically to handle compression forces, shear forces and stabilize the knee in order to allow the surrounding joints, hip and ankle to operate effectively. The knee itself only moves (outside of injury) mostly through extension and flexion with very minimal rotation. The four ligaments (I’ll add the patella as a fifth) are incredibly positioned within the joint structure for internal and external stability while allowing maximal torque angles. Two ligaments on the inside (between the femoral epicondyles and tibial condyles), holding the knee together vertically, laterally, and horizontally. The outer ligaments hold the lateral and medial sides of the joint together, preventing lateral flexion and rotation.
Here’s the way knee pain works (now that we’ve gone too far into the anatomy, let’s go over its physiology). Most acute knee injuries are due to outside forces striking the knee from the outside, think of football and someone rolling over a players leg. Think of stepping off a curb, watching your ankle ‘roll’, while your knee compensates and as the hip externally rotates, it goes bow-legged.
Recommendations for knee injuries and knee injury prevention:
1. Have a postural assessment done. I recommend the Functional Movement Screen as an initial test. Secondary tests like goniometer tests are great as a secondary test.
FMS Hamstring Assessment
2. Identify pain (if any). What part of the knee hurts? When? Does it hurt when you stand and ‘lock out’ your knee? Specific activities that cause pain? See a doctor if pain persists. Always.
3. Look at your shoes. No, the bottom of them. Wear patterns are a key indicator on knee joint stress (also hips and ankles). Outer wear on your shoe indicates external rotation of the hip, thus ACL, medial meniscus and LCL stress.
4. Improve hip flexibility through soft tissue repair. Hip external rotators, abductors are notorious culprits, so use foam rolling, PNF stretching, stretch at your desk, and be receptive to techniques that focus on soft tissue
Bullets for knee structure and propensity to injury:
ACL(anterior cruciate ligament)- This guy attaches to the anterior, meaning front, of the tibial area. It doesn’t like extreme internal rotation with lower leg flexion or hyperextension!! It normally operates by holding the knee directly together but has to go around the lateral condyle of the femur, so it is very sensitive to internal rotation injuries!! Think blunt force to the outside of the knee.
MCL(medial collateral ligament or tibial collateral)- this guy runs vertically on the inside of your knee. If you knock your knees together, you’re hitting them. Stop doing that.
PCL(posterior cruciate ligament)-since I didn’t mention what cruciate meant, it means cross. The PCL is stronger than the ACL (thus fewer injuries and not as glamorous), and is locate behind the ACL in an X pattern behind the femoral-tibial articulation. These guys are like shoelaces behind the knee, working together to keep the knee both held down vertically and horizontally at the same time. It really is quite amazing the way these ligaments are built!!
LCL(lateral collateral ligament or fibular collateral)- This one is why I incorporate the fibula in the discussion. The LCL attaches to the fibula, instead of the tibia and makes this joint even more complex. The word collateral in this context doesn’t mean money or leverage like in the movies, it means parallel and coordinating, in particular, with the MCL.
Patella-This ligament/tendon hybrid helps hold the quadriceps to the patella and the anterior surface of the tibia for extension. The ligament itself only really holds the patella to the tibia, but since it moves in conjunction with the patellar tendon, I think it would be a mistake to not include it. In order to injure this guy, you need exteme rapid or hyperflexion of the knee (rare).
Meniscus- when uneven wear occurs in the knee due to improper posture, blunt force causes extreme uneven pressure within the knee, usually due the knee being bent and twisted (ouch, and usually goes along with an ACL and MCL tear)
Pain in the knees, particularly over time, is normally a response to a joint that is compensating for a hip or ankle issue. Just because pain is located in the knee, doesn’t mean that it is caused by the knee itself. If you have knee pain, stiffness, soreness or just plain immobility, have a Fitness Coach review your posture, run an assessment and look at how to correct it. And please, don’t blow out your knee….
Sources:
1. Marieb, Elaine Nicpon. Human anatomy and physiology/ 5th edition. p. cm. 2001
2. Neiman, David C. Exercise testing and prescription: a health related approach/ 5th edition. p. cm. 2003.
3. FunctionalMovement.com. 2009. “The system for a simple and quantifiable method of evaluating basic movement abilities” publication 2006. http://www.functionalmovement.com/SITE/publications/downloads/FMSPB.pdf.
4. The Functional Movement Screen. FMS Manual. Gray Cook. 2005.
5. Image: Knee ligaments. Mayoclinic.com. 2009. http://www.mayoclinic.com/health/medical/IM02487
