There are four ligaments in the knee: the anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), medial collateral ligament (MCL), and lateral collateral ligament (LCL). The ACL and PCL stabilize front-to-back knee movements, while the MCL and LCL stabilize side-to-side movements.

The ACL can be sprained or torn if the knee is straightened beyond its normal limits (hyperextended), twisted, or bent side-to-side. A sprained or torn ACL is common in sports and usually results from a hard stop or aggressive twisting of the knee. The PCL is the least common ligament to be injured.

The MCL is injured when a force is exerted on the outside of the knee, pushing it inward, while the LCL is injured by a force exerted on the inside of the knee that pushes it outward. This type of hit is frequent in contact sports like football or hockey.

A torn knee ligament is usually accompanied by feeling or hearing a pop in the knee at the time of injury, severe pain and swelling, and joint instability.

Degenerative disk disease is a general term applied to back pain that has lasted for more than three months. It is caused by degenerative changes in the intervertebral disks in the spine and can occur anywhere in the spine: low back (lumbar), mid-back (thoracic), or neck (cervical).

Under the age of 30, these disks are normally soft, and they act as cushions for the vertebrae. With age, the material in these lumbar disks becomes less flexible and the disks begin to erode, losing some of their height. As their thickness decreases, their ability to act as a cushion lessens. The less dense cushion now alters the position of the vertebrae and the ligaments that connect them. In some cases, the loss of density can even cause the vertebra to shift their positions. As the vertebrae shift and affect the other bones, the nerves can get caught or pinched and muscle spasms can occur.

Degenerative disk disease is primarily a result of the normal aging process, but it may also occur as a result of trauma, infection, or direct injury to the disk. Heredity and physical fitness may also play a part in the process.

Stenosis refers to a narrowing of the spinal canal, usually in the lower back (lumbar) region. This narrowing is often a result of the normal degenerative aging process. It occurs as the disks of cartilage that separate the spine’s vertebrae lose water and the space between the vertebrae become smaller, causing friction between the bones. The loss of water in the disks makes them less flexible and unable to act as shock absorbers in the spine. Daily wear and tear on the spine becomes more significant without these shock absorbers.

As the disks degenerate, vertebrae may shift, causing the spinal canal to narrow. In some cases, the nerves that travel through the spinal column to the legs become squeezed. This can cause back and leg pain, and even leg weakness. Arthritis and falls also contribute to the narrowing of the spinal canal, compressing the nerves and nerve roots and causing pain and discomfort.

In the low back, nerves join to form the sciatic nerve, which runs down into the leg and controls the leg muscles. Sciatica is a condition that may cause radiating pain, numbness, tingling, and/or muscle weakness in the leg but originates from nerve root impingement in the lower back. Nerve impingement is most often caused by a herniated disk or spinal stenosis.

A strain occurs when a muscle is stretched or torn. A sprain occurs when a ligament is stretched or torn.

Strains are often the result of overuse or improper use of a muscle, while sprains typically occur when a joint is subjected to excessive force or unnatural movements (e.g., sudden twists, turns, or stops). Sprains can be categorized by degree of severity:

• A first-degree sprain stretches the ligament but does not tear it. Symptoms include mild pain with normal movement.
• A second-degree sprain is characterized by a partially torn ligament, significant pain and swelling, restricted movement, and mild to moderate joint instability.
• In a third-degree sprain, the ligament is completely torn with mild to severe pain, swelling, and significant joint instability.

An epidural is a potent steroid injection that helps decrease the inflammation of compressed spinal nerves to relieve pain in the back, neck, arms or legs. Cortisone is injected directly into the spinal canal for pain relief from conditions such as herniated disks, spinal stenosis, or radiculopathy. Some patients may need only one injection, but it usually takes two or three injections, given two weeks apart, to provide significant pain relief.

Cortisone is a steroid that is produced naturally in the body. Synthetically-produced cortisone can also be injected into soft tissues and joints to help decrease inflammation. While cortisone is not a pain reliever, pain may diminish as a result of reduced inflammation. In orthopaedics, cortisone injections are commonly used as a treatment for chronic conditions such as bursitis, tendinitis, and arthritis.

A tendon is a band of tissue that connects muscle to bone. A ligament is an elastic band of tissue that connects bone to bone and provides stability to the joint. Cartilage is a soft, gel-like padding between bones that protects joints and facilitates movement.

Physical therapy is the treatment of musculoskeletal and neurological injuries to promote a return to function and independent living. Physical therapy incorporates both exercise and functional training. Exercise restores motion and strength while functional training facilitates a return to daily activities, work, or sport.

Ice should be used in the acute stage of an injury (within the first 24-48 hours), or whenever there is swelling. Ice helps to reduce inflammation by decreasing blood flow to the area in which cold is applied. Heat increases blood flow and may promote pain relief after swelling subsides. Heat may also be used to warm up muscles prior to exercise or physical therapy.