Types of Injuries and How They Heal

by John Howick
© 2003

A SPRAIN is a stretching or tearing of a ligament. Ligaments connect one bone to another and their job is to keep a joint stable. In normal movement, ligaments aren’t usually stressed but if a joint is forced to bend in an abnormal direction, the ligament tries to control this movement and fibres of the ligament can be torn. Common areas where people sprain ligaments are at the thumb (“Skier’s Thumb”), the ankle (“rolling your ankle”), the knee (the MCL or ACL), and the collarbone or A.C. joint (“a separated shoulder”).

A STRAIN is an over stretching or tearing of a muscle. Muscles are attached to bone via a tendon. Muscles that are commonly strained are the quadriceps (front thigh), hamstrings, groin and calf.

A TENDINOSIS is weakness, pain and sometimes inflammation of a tendon. A tendinosis can develop after an acute injury such as strain or bruise but can also develop gradually. We call this an “Over-use” injury and it is usually from doing our sport with too much intensity or too little rest, especially at the beginning of the season. Common areas of tendinosis are at the shoulder (rotator cuff), the Achilles tendon, the knee (jumper’s knee) and the elbow (tennis elbow).

To understand how we treat these injuries we have to understand the stages our body goes through when tissue has been damaged.

Stage 1- Inflammatory- This occurs immediately after an injury and lasts a minimum of 2 days but often extends for many weeks. This is when we see the most pain, redness, heat and swelling at the injury site. Treatment at this stage you already know…PRICE!

Stage 2- Repair -After the first 2 days and for the next 3 weeks, your body repairs the torn collagen fibres by laying down a mesh of new collagen. What happens on the inside is very similar to what you see on the outside when you get a cut. The “scar” you see is new collagen fibres.

Stage 3- Remodeling- This stage begins at 3 weeks and continues for many months. The initial “scar” that was formed at the injury site is very weak and tends to get very tight. In the remodeling stage the scar is gradually transformed and becomes stronger and more flexible until it is almost identical to the surrounding muscle or ligament tissue.

Ligaments, muscles, and tendons have collagen fibres arranged in specific patterns ensuring they can meet the forces put on them. Think about a rope made up of many smaller strands braided and wound to make it strong but not bulky. Imagine you cut 45 % of those fibres. The rope could not hold as much weight. If you put a large force through it more fibres would tear and the rope may fail. So you decide to fix it. You take a bunch of short fibres, toss them on the rope in any old direction, throw in some white glue and let it set for a few hours. How strong do you think it will be? You are right, not much stronger than before your quick repair. This is what is happening in the second and third week after an injury. New collagen is being laid down in an unorganized mesh. It is still not strong and it gets tight (some fibres and “glue” get stuck to surrounding tissues). What does this mean as far as treatment of your sprained ankle or strained hamstring? The answer is “progressive, gentle, controlled movement”. The movement stimulates collagen to be laid down and helps regain your mobility. It must be gentle and controlled because the collagen is weak and if moved too much or in the wrong direction the injured part will be damaged again and return to the Inflammation stage. This means more swelling, more pain, more stiffness, and more time off your sport. How do you know which way to move, how much to move and how quickly to progress? That is where a physiotherapist comes in. Physiotherapists are movement specialists and can guide you through this stage of healing with an exercise program and passive mobilization/stretching specific to you and your injury.

What happens after three weeks? Most of the new collagen is laid down but it still isn’t the same as the ligament or muscle that was there before the injury. In the last stage, collagen is remodeled to make it strong and mobile to take all you can throw at it. By six weeks post injury, most mild to moderate injuries are healed enough to allow gradual return to normal activity. This time line assumes you have done all the right things as you progressed through the stages of healing. From the three week to the six-week mark you should be working on vigorous exercises to stretch and strengthen your muscles, improve your balance and coordination and retrain your body for the movements required in your sport. If you injury was more severe you may require a brace to give you added protection when you go back to your activity.

Is your collagen 100% at six weeks? Absolutely not. It takes 3 months to regain 80% strength in your collagen and it continues to remodel for up to 18 months. This doesn’t mean you have to sit out a year but you need to be faithful with your exercises for many months after your injury. Follow these guidelines and before long you will be back in the game.