• this ligament, located in the center of the knee is 3.5 cm (about 1.5 inches) in length
• crosses its sister ligament (posterior cruciate) to form an “X” (thus the name cruciate–Latin for cross)
• attaches in front of the posterior cruciate (anterior means towards the front) on the leg bone (tibia)
• main function is to resist the forward movement of the tibia                             
• secondary function is to resist rotation of the lower leg
• the ACL is weaker than the PCL                                                                                     
• most animals that have knee joints have an ACL-like structure                         
• the ACL is the most commonly injured knee ligament
• in the USA, approximately 100,000 ACL tears occur every year                      
• in the USA, 65-70,000 ACL surgeries are performed every year
• most ACL tears occur in non-contact situations

What is gait? Gait is a manner of walking, stepping or running. More specifically, it is a series of rhythmical, alternating movements of the trunk and limbs which result in the forward progression of the center of gravity (body).  Another way to think of gait is as a series of “controlled falls”.

How is gait evaluated? We visually observe patients walking on a treadmill or up and down a long hallway. A treadmill allows us to precisely control speed and to observe close-in. If necessary, patients can also be recorded on video while walking/running. The video can then be slowed down, reversed, repeated, etc. as needed to perform a more detailed assessment of gait. 

Some of the things we look forduringa gait evaluation are symmetry of the gait cycle, step and stride length, cadence, and walking base. Symmetry is one of the most important aspects of gait. The movement of one side of the body should mirror the other side of the body. Arm swing, foot placement, step length, foot impact should all be very similar right vs. left.

Injuries and or weakness often lead to heavier impact (usually, but not always) on the opposite side. Since the average human takes 10-15,000 steps each day, increasing the impact of one foot by a force of just 10 lbs (each step) can add up to a lot of extra stress being added to that leg (upwards of 75,000 lbs) every day. No wonder “bad” walking mechanics eventually lead to more injuries.

Another common gait deviation is foot placement. If a patient is having difficulty controlling where the foot is landing (for example: too close to the other leg, turned out/in), they may have  significant hip muscle weakness or neurological issues.

The vast majority of gait deviations can be corrected or compensated for with proper training. Most physical therapists are experts in gait evaluation and training. Left untreated, significant gait deviations can lead to injury. Taking that first step, and getting a gait evaluation, could be a step in the right direction for better health.

Being active is a way of life—-it is what humans are designed for. An inactive lifestyle is a learned activity, an accumulation of bad habits. Perhaps, whether a person makes exercise a priority is determined by the subconscious mind. How do you know if you have a subconscious mind that favors exercise?

I have developed a list of ten actions that a person with an “active” mind-set might perform. See how many you perform on a regular basis.

• take the stairs whenever possible, especially if it is a matter of  only 1-3 flights.
• walk or bike for short-distance errands (1-3 blocks)
• walk a golf course instead of using a cart
• take your dog or cat for a walk instead of letting them run around the neighborhood off-leash
• park in the first available parking spot instead of circling the area until you find a closer parking spot
• getting out of your car and going to the front door of a house instead of honking your horn and expecting that person to run out to your car
•  carrying your luggage instead of pulling/rolling your bags
• carrying your grocery bags to your car instead of using a cart
• bringing your grocery cart back to the store or cart area vs. leaving the cart next to your parking spot
• clean your home on a regular basis vs. hiring a cleaning service—-same thing with yard work

How “active” is your mind-set? If you perform 7 or more of these actions on a regular basis, then you are internally motivated to exercise daily . If you perform 3-6 regularly, then you have an “active” mind-set but may need a little motivation to exercise regularly. If you infrequently perform any of these actions, you probably need a lot of motivation to exercise…if you exercise at all.

Being active is a personal choice—it really is “all in your head”.

• shock absorption is lost forever
• since the spacer on the one side of the joint is missing, more forces are transmitted through that side of the joint
• the joint surfaces of the femur (thighbone) and tibia (shinbone) are going to become stressed, softened, and eventually break down (’arthritis’) and there will be arthritic pain
• the leg may demonstrate ‘bow legged ness’ or ‘knock-knees’, due to the collapse of the joint on the one side (one ‘compartment’)
• the bone may attempt to try to heal the problem - causing totally unhelpful bony outgrowths called ‘osteophytes’ (’bone mushrooms’). These may form at the joint line or in the notch where the cruciate ligaments reside.
• eventually the cruciate ligaments may become incompetent and rupture

Recently, a synthetic meniscus has been developed and is being used primarily in Europe. This implant is made from a slowly degrading polyurethane foam and is designed to treat irreparable meniscal tears. It provides a structrue for the in-growth of tissue in the meniscus, after the removal of the damaged meniscal tissue by the surgeon. The body of this implant is highly porous—some 80% of the implant is air—and allows blood vessels to grow into the material and tissue to be generated around them.

The implant degrades over four to six years and is removed/replaced by the body’s own tissue. Patients are usually non-weigtbearing for an extended period of time (comparable to a meniscal repair or transplant) and are restricted to 90 degrees of loaded knee flexion for up to 6 months. Impact activities such as running or jumping can be introduced at 9-12 months. Full return to sports activities is the expected outcome.

Maintaining  healthy tissue is important for normal pain free knee function. A synthetic meniscus now allows surgeons to replace damaged tissue with (eventually) near-normal tissue, preventing or at least greatly reducing the risks associated with menisectomy.

Stretching isn’t necessary for muscles to perform, but stretching is necessary for muscles to perform well. Our muscles, much like an automobile engine, perform better when they are warmed up. Muscles have a modest amount of fuel (”energy”) stored in them at rest so that they can perform immediately when called upon. But the body needs to rev up its “fuel delivery” system to keep the muscle functioning beyond a few seconds. The heart will need to beat faster, more muscle fibers will need to be activated,  junk that has accumulated since the muscle was last used will need to be removed….all part of the warm up process. As a muscle warms up, it is better able to handle stress. And stretching is stressful to a muscle.

Too much stress can injure a muscle. If a muscle is warmed up, it is less likely to suffer damage from any activity,  including stretching. But, is stretching even necessary?

For light activity, stretching isn’t necessary. Stretching is necessary though, if you plan to put the body through movements or positions beyond normal range. For example, because jogging and walking stress the body in similar movement ranges,  it isn’t necessary to stretch before jogging if you have been walking around for a while. But if you plan on running fast, stretching is necessary because the muscles will be moving through a much greater range than they have been “primed” for.

Unless muscles are stretched, they will resist movement beyond normal—-and normal is the range muscles are being used in at any given time. In order to run fast, the hip/knee/ankle joints need to move in a greater range than is needed for jogging. Stretching prepares a muscle (and joints) for increased range of movement, decreasing the risk of injury.

Stretching doesn’t need to be mysterious—just remember a few simple points:

• warm up (sustained light activity for 10-15 minutes) before stretching
• stretch before engaging in more vigorous than normal activities
• stretching prepares a muscle for use over a greater range of movement
• stretching decreases the risk of injury