205 Diseases, Disorders, and Injuries of the Joints

Sprain and Strain

A strain is a tear in tendon fibers resulting from overstretching, while a sprain is an equivalent injury to a ligament.

Learning Objectives

Describe a strain and its treatment

Key Takeaways

Key Points

  • Strains and sprains can happen to anyone, but athletes are at higher risk.
  • P.R.I.C.E. is a treatment method for muscular strain: protection, rest, ice, compression, elevation.
  • Cold compression therapy uses ice packs and wrapping to reduce swelling and inflammation to encourage the healing process.

Key Terms

  • strain: An injury to a muscle or tendon in which the muscle fibers tear as a result of overstretching.
  • sprain: To weaken a ligament by sudden and excessive exertion, as by wrenching; to overstrain, or stretch injuriously, but without luxation; as, to sprain one’s ankle.


Gymnasts frequently suffer from mild ankle sprains. Cold compression therapy is the recommended treatment. As soon as possible, the gymnast needs to begin to take brief walks as part of rehabilitative therapy. Failure to rehabilitate the ankle can permanently weaken it.

A strain is an injury to a muscle or tendon in which the muscle fibers tear as a result of overstretching. A strain is also colloquially known as a pulled muscle. The equivalent injury to a ligament is a sprain. Typical symptoms of a strain include: localized pain, stiffness, discoloration, and bruising around the strained muscle. Strains can happen while doing everyday tasks and are not restricted to athletes. Nevertheless, people who play sports are more at risk of developing a strain due to increased muscle use.

This image shows a man's leg muscle strain after 4 days.

Muscle Strain: Pulled hamstring after four days. Two images of the same leg. One of the pictures was taken in a mirror.

Treatment of Strains and Sprains

The first-line treatment for a muscular strain in the acute phase includes five steps commonly known as P.R.I.C.E.

  • Protection: Apply soft padding to minimize impact with objects.
  • Rest: Don’t use the injured limb.
  • Ice: Apply ice to reduce swelling by reducing blood flow to the injury site. Never ice for more than 20 minutes at a time.
  • Compression: Wrap the strained area to reduce swelling with an ACE soft-wrapped bandage.
  • Elevation: Keep the strained area as close to the level of the heart as is conveniently possible to keep blood from pooling in the injured area.

The ice and compression (cold compression therapy) will stop the pain and swelling while the injury starts to heal itself. Controlling the inflammation is critical to the healing process and the icing further restricts fluid leaking into the injured area as well as controlling pain.

This immediate treatment is usually accompanied by the use of non-steroidal anti-inflammatory drugs (e.g., ibuprofen), which both reduce the immediate inflammation and relieve pain. However, NSAIDs, including aspirin and ibuprofen, affect platelet function (this is why they are known as “blood thinners”) and should not be taken during the period when tissue is bleeding because they will tend to increase blood flow and inhibit clotting. After the bleeding has stopped, NSAIDs can be used with some effectiveness to reduce inflammation and pain. It is recommended that the injured person should consult a medical provider if the injury is accompanied by severe pain, if the limb cannot be used, or if there is noticeable tenderness over an isolated spot. These can be signs of a broken or fractured bone, a sprain, or a complete muscle tear.

Rheumatism and Arthritis

Rheumatoid arthritis is a chronic, systemic inflammatory disorder that affects many tissues and organs, but mainly attacks flexible joints.

Learning Objectives

Differentiate rheumatoid arthritis from osteoarthritis

Key Takeaways

Key Points

  • Rheumatism is an archaic term for problems related to joints and connective tissues that has been replaced with the field of rheumatology.
  • Although the cause of rheumatoid arthritis is unknown, autoimmunity plays a pivotal role in both its chronicity and progression; it is considered a systemic autoimmune disease.
  • The discovery that vitamin D plays a role in immune regulation has led research showing improvement in patients with rheumatoid arthritis who had high plasma levels of 25(OH)D3.
  • There are over 100 types of arthritis and osteoarthritis is the most common.
  • Arthritis is the most common cause of disability in the U.S. as it makes physical activity very difficult for those suffering from it.

Key Terms

  • rheumatism: Any disorder of the muscles, tendons, joints, bones, nerves, characterized by pain, discomfort, and disability.
  • rheumatoid arthritis: A chronic and progressive disease in which the immune system attacks the joints. It is characterised by pain, inflammation and swelling of the joints, stiffness, weakness, loss of mobility, and deformity. Tissues throughout the body can be affected including the skin, blood vessels, heart, lungs, and muscles.


Kathleen Turner, the actress from the movie Body Heat found out when she was in her mid-40s that she suffered from rheumatoid arthritis. The crippling pain made her life almost intolerable. But with the help of medical treatment and exercise, she battled back to return to acting.

Rheumatism or rheumatic disorder is a non-specific term for medical problems affecting the joints and connective tissue. The study of, and therapeutic interventions in, such disorders is called rheumatology. The term “rheumatism” is still used in colloquial speech and historical contexts, but is no longer frequently used in medical or technical literature; there is no longer any recognized disorder simply called “rheumatism.” Some countries use the word rheumatism to describe fibromyalgia syndrome. The term “Rheumatic Diseases” is used to refer to connective tissue disorders.


Rheumatoid Arthritis: A hand affected by rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic, systemic inflammatory disorder that may affect many tissues and organs, but principally attacks flexible (synovial) joints. The process involves an inflammatory response of the capsule around the joints (synovium) secondary to swelling (hyperplasia) of synovial cells, excess synovial fluid, and the development of fibrous tissue (pannus) in the synovium. The pathology of the disease process often leads to the destruction of articular cartilage and ankylosis (fusion) of the joints. Rheumatoid arthritis can also produce diffuse inflammation in the lungs, the membrane around the heart (pericardium), the membranes of the lung (pleura), and the white of the eye (sclera), and also nodular lesions, most common in subcutaneous tissue. Although the cause of rheumatoid arthritis is unknown, autoimmunity plays a pivotal role in both its chronicity and progression, and RA is considered a systemic autoimmune disease.

Treatment of Rheumatoid Arthritis

There is no known cure for rheumatoid arthritis, but many different types of treatment can alleviate symptoms and/or modify the disease process. The goals of treatment include minimizing clinical symptoms such as pain and swelling, as well as preventing bone deformity and radiographic damage (for example, bone erosions visible in x-rays), and maintaining the quality of life in terms of day-to-day activities. The discovery of the vitamin D receptor (VDR) in the cells of the immune system and the fact that activated dendritic cells produce the vitamin D hormone suggested that vitamin D could have immunoregulatory properties. 25(OH)D3 plasma levels have been found inversely correlated, with the RA disease activity showing a circannual rhythm (more severe in winter). Recently, greater intake of vitamin D was associated with a lower risk of RA. A significant clinical improvement was strongly correlated with the immunomodulating potential in vitamin D-treated RA patients.


Osteoarthritis: Severe osteoarthritis and osteopenia of the carpal joint and first carpometacarpal joint.

There are over 100 different forms of arthritis. The most common form, osteoarthritis (degenerative joint disease), is a result of trauma to the joint, infection of the joint, or age. Osteoarthritis is characterized by a lack of primary inflammation. Other forms of arthritis include rheumatoid arthritis, psoriatic arthritis, and related autoimmune diseases. Septic arthritis is caused by joint infection. The major complaint by individuals who have arthritis is joint pain. Pain is often a constant and may be localized to the joint affected. The pain from arthritis is due to inflammation that occurs around the joint, damage to the joint from disease, daily wear and tear of joint, muscle strains caused by forceful movements against stiff, painful joints, and fatigue.

Arthritis is the most common cause of disability in the United States. More than 20 million individuals with arthritis have severe limitations in function on a daily basis. Absenteeism and frequent visits to the physician are common in individuals who have arthritis. Arthritis makes it very difficult for individuals to be physically active and many become home bound. Treatment options vary depending on the type of arthritis and include physical therapy, lifestyle changes (including exercise and weight control), orthopedic bracing, and medications. Joint replacement surgery may be required in eroding forms of arthritis. Medications can help reduce inflammation in the joint which decreases pain. Moreover, by decreasing inflammation, the joint damage may be slowed.

Common Joint Injuries

Common joint injuries include shoulder injuries, elbow injuries, and knee injuries.

Learning Objectives

Describe common joint injuries

Key Takeaways

Key Points

  • Common shoulder injuries include rotator cuff tears, dislocation, and separated shoulder.
  • Common elbow injuries are primarily due to overuse. These include tennis elbow and golfer’s elbow.
  • Common knee injuries can be due to overuse or due to traumatic tears, such as the common ACL tear that occurs most often in sports.

Key Terms

  • ACL: The most commonly injured ligament of the knee.

Shoulder Injuries

This instability increases the likelihood of joint injury, often leading to a degenerative process in which tissues break down and no longer function well.

Rotator Cuff Tear

The term “rotator cuff” refers to a group of four tendons that blend together as they attach to the upper end of the arm bone (humerus). Normally these tendons transmit the force of muscles originating on the shoulder Blase (scapula) to the arm providing motion and stability. Defects in the rotator cuff can come from an injury (cuff tear) or from degeneration (cuff wear). The degree to which a tendon is reparable depends on its quantity and quality. Degenerated tendons are often frail and retracted and may not be amenable to repair. Individuals that are elderly, smokers, or those having had cortisone injections often have weaker tendon tissue that fails without a significant injury. By contrast, those whose tendon was torn by a substantial fall often have good quality tendon that can be repaired if surgery is performed promptly after the injury.

Dislocated Shoulder

The shoulder joint is the most frequently dislocated major joint of the body. In a typical case of a dislocated shoulder, a strong force that pulls the shoulder outward (abduction) or extreme rotation of the joint pops the ball of the humerus out of the shoulder socket. Dislocation commonly occurs when there is a backward pull on the arm that either catches the muscles unprepared to resist or overwhelms the muscles. When a shoulder dislocates frequently, the condition is referred to as shoulder instability. A partial dislocation where the upper arm bone is partially in and partially out of the socket is called a subluxation. In the medical community, dislocation is commonly referred to as luxation.

Separated Shoulder

A shoulder separation occurs where the collarbone (clavicle) meets the shoulder blade (scapula). When ligaments that hold the AC (acromioclavicular) joint together are partially or completely torn, the outer end of the clavicle may slip out of place, preventing it from properly meeting the scapula. Most often the injury is caused by a blow to the shoulder or by falling on an outstretched hand. After injury it is hard to do a 180 degrees rotation.

Elbow Injuries

The types of disease most commonly seen at the elbow are due to injury.


Two of the most common injuries at the elbow are overuse injuries: tennis elbow and golfer’s elbow. Golfer’s elbow involves the tendon of the common flexor origin which originates at the medial epicondyle of the humerus (the “inside” of the elbow). Tennis elbow is the equivalent injury, but at the common extensor origin (the lateral epicondyle of the humerus).


There are three bones at the elbow joint, and any combination of these bones may be involved in a fracture of the elbow.

Knee Injuries

Knee pain can be caused by trauma, misalignment, and degeneration as well as by conditions like arthritis. The most common knee disorder is generally known as patellofemoral syndrome.The majority of minor cases of knee pain can be treated at home with rest and ice but more serious injuries do require surgical care.

Physical fitness is related integrally to the development of knee problems. The same activity such as climbing stairs may cause pain from patellofemoral compression for someone who is physically unfit, but not for someone else (or even for that person at a different time).

ACL Tear

The anterior cruciate ligament (ACL) is the most commonly injured ligament of the knee. The injury is common during sports. Twisting of the knee is a common cause of over-stretching or tearing the ACL. When the ACL is injured a popping sound may be heard, and the leg may suddenly give out. Besides swelling and pain, walking may be painful and the knee will feel unstable. Minor tears of the anterior cruciate ligament may heal over time, but a torn ACL requires surgery. After surgery, recovery is prolonged and low impact exercises are recommended to strengthen the joint.


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