Pro Motion Physiotherapy & Sports Injury Clinic

Ligament Injuries

Definition and Anatomy/Histology

Ligaments are fibrous, white bands or cords of connective tissue which join bone to bone. As very complex structures, they attach onto strategic points on the bones and loosen and tighten in different joint positions. Some ligaments, such as those around the shoulder and hip, blend right into the joint capsule (the sheet-like material which surrounds all joints in the body), strengthening it in key areas. Ligaments are approximately two thirds water and one third solid material. The high water content accounts partly for a ligaments ability to adapt to various loads.

Function

Ligaments have primarily 3 roles:

1. They guide movement of bones during joint motion, preventing abnormal motion.
2. They stabilize the joint when outside forces are applied to the joint (eg. a blow to the side of the knee).
3. They provide feedback which informs the muscles how they need to react as the position and forces on the joint change.

Behavior

Ligaments are stronger in some positions than others. When a ligament is not being stressed the fibers form a kind of 'crimped' formation (similar to 'crimped' hair). As the ligament is stressed/stretched, the initial looseness in the fibers, due to the crimp, is taken up. If the stress continues, the various fibers in the ligament are progressively recruited until all the crimp is taken out, and all the fibers in the ligament are tight. If continued force is applied, the fibers that tightened first will be the first to tear. Further/complete ligament failure/tearing is fast to follow if the force is not removed.

If a ligament is stretched, but the force is not great enough to cause the ligament to tear, it will return to its' normal length once the force is removed. This is due to the elastic type of material found in ligaments.

Effects of Aging

Ligaments are strongest and perform at their peak between the ages of 18-20 years. Before this time, the ligaments are smaller, they are more easily stretched. Their insertion points onto the bones are points of weakness and are commonly seen as injury sites in children. With aging, the ligaments lose some of their water content, they become less elastic, and the insertion points onto bones weaken. Thus, ligament injuries are more common in active middle aged people. In the elderly, bones are typically more fragile than ligaments and are more commonly injured than the ligaments.

Phases of Healing

Immediate local pain, bleeding and inflammation follow a ligament tear. Blood platelets released promote clotting and the various chemicals and growth substances released begin the healing process. Within several days scar tissue begins to be laid down. It appears that ligaments heal primarily by scar tissue and not by replacement of the original ligament material.

Over the next several weeks, the inflammatory response subsides, the scar tissue becomes more flexible and fragments of the damaged ligament and remaining blood clot are removed. Once the gap in the torn ligament has been filled, the scar tissue begins to remodel and becomes stronger and more highly organized. It takes approximately 3-5 weeks for ligaments to heal, however, they will never be as strong as they were prior to injury.

Effects of Immobilization

There remains some controversy on the effects that immobilization has on ligaments. It appears that the ligament looses strength, size and stiffness, and the bone-ligament interface weakens. Short periods of immobilization show little negative effect on the ligament, whereas immobilization for periods between 6-9 weeks in length cause about a 50% loss of ligament strength and stiffness.

Early immobilization of a damaged ligament helps to prevent the laxity (looseness) found in healing ligaments. However, it also reduces the quantity and quality of scar tissue laid down, thus limiting the ligaments ability to resist higher loads once it is healed. Other joint structures are also affected by immobilization and include joint stiffness, bone and muscle loss, and cartilage degeneration.

Effects of Exercise

Exercise and movement have been shown to have beneficial effects on healing ligaments as well as the non-injured ligaments and surrounding joint structures, providing that the forces exerted are not too great. Currently, it is unknown what the optimal forces are, but it is thought that very low, cyclical loading on a ligament will promote scar tissue formation and structure in a manner such that the ligament becomes stronger and stiffer.

Why Pro Motion Physiotherapy?

Treatment at Pro Motion Physiotherapy is beneficial for the recovery from ligament injuries for the following reasons:

• Aides in decreasing and limiting pain and inflammation
• Provides guidance on appropriate activities to safely load the healing ligaments without causing further damage, thus creating the strongest possible repair
• Limits the effects of immobilization such as joint stiffness, muscle weakness, cartilage degeneration, weakened tendons and ligaments