Knee Pain

1 Knee Pain Summary

Knee pain is a very common condition that may be caused by a variety of reasons including injuries, wear and tear, and medical conditions.

It affects people of all age group but is more common among elderly and in people who are into sports and recreational activities. The pain may be diffused around the knee joint or at a specific position. In most of the cases, knee pain is associated with some degree of restriction in movement. 

Knee pain may be caused by injury to any of the parts associated with joint – bones, tendons, muscles, ligaments, cartilage, and bursae. Three different bones go into the formation of this joint – thigh bone, shin bone, and knee cap.

The bones are held together by ligaments and muscles. Cartilage lines the joint and provides lubrication and aids in articulation. Bursae, the fluid-filled compartments of the knee, provides additional lubrication to this joint.

The most common cause of knee pain is a sudden injury. Injuries may be acute or overuse injuries. Knee pain may also result from reasons other than direct injury to the parts of the joint. Conditions like osteoarthritis, skin infections, cysts, pinched nerve, and arthritis also result in pain in the knees.

Knee pain is found in around 19% of the people, and the incidence of pain in this joint increases with age. The intensity of pain also is found to increase with age and in most people pain is associated with some amount of mobility issues.

Knee pain is found to be more common among females when compared to males. Studies show that knee pain affects 23% of women above 60 years, while the rate of incidence in men in this age group is 18%. The prevalence was found to be more in the age group 85 to 90 years.

Chronic knee pain is very less in children, and this might be due to the reduced occurrence of degenerative conditions in this age. The prevalence increases slightly with age, with adolescents having an incidence rate of 18%.

The progress of pain often depends on the condition. Ligament ruptures and strain in meniscus may cause trauma in the joint, while conditions like osteoarthritis result in chronic pain and mobility issues.

Some acute conditions like septic arthritis may result in the destruction of the joint and need immediate attention. Pain due to overuse of the joint may reduce by abstaining from activities. Imaging techniques like x-ray are the most commonly used diagnostic method for knee pain.

Blood test for rheumatoid factor, cultures, and white cell count are also used to diagnose the medical conditions that lead to knee pain.

Treatment of knee pain is based on the actual cause of pain. Physiotherapy, occupational therapy, analgesics, alternative therapies, steroids, and surgery are recommended for specific causes of knee pain. Most people do not visit a doctor for treating knee pain.

There are situations when one should visit the practitioner for alleviating symptoms. This includes:

  • Inability to put weight on the knee
  • Severe pain
  • Painful locking
  • Fever, redness, and heat around the joint
  • Pain, swelling, and numbness of calf
  • Inability to bend or straighten the knee

2 Causes

Knee pain is caused by:

  • Acute injury
  • Medical conditions
  • Overuse or chronic use

Acute injuries result from:

  • Ligament or tendon injury that result in sprains
  • Tear in the meniscus, the cartilage that forms a cushion between shin bone and thigh bone. This may result from sudden twisting of knees
  • Ligament tear, including anterior cruciate ligament (ACL) and medial collateral ligament (MCL). Ligament tear also results from a sudden change in directions or a sudden stop.
  • Fractures of the kneecap, femur, and upper part of tibia and fibula. Fractures of the bones in the joint often result from falling on the knee, the sudden twisting motion of the joint, or by a sudden and forceful hit on the knee.
  • Dislocation of the kneecap is a cause of acute injury that leads to knee pain. This is very commonly seen in girls in the age group of 13-18 years.
  • Loose bodies like a piece of bone or cartilage sometimes float in the joint space and interfere with the movement of the joint. This can cause acute injury to the joint.
  • Knee joint dislocation is a rare cause of acute injury leading to knee pain. It often happens after an accident during which the knee hits a hard object.

Medical conditions that result in knee pain include:

  • Degenerative diseases like osteoarthritis are one of the most common causes of knee pain. This pain is worse in the morning reduces gradually during the day. Other diseases like gout, pseudogout, rheumatoid arthritis also lead to pain, swelling, and stiffness in the joint.
  • Baker’s cyst, also known as popliteal cyst, cause pain and swelling in the knees
  • Skin infections like cellulitis, infectious arthritis, osteomyelitis, and septic bursitis can cause pain and affect the movement of the joint
  • A pinched nerve in one part of the body may lead to pain in the knees
  • Osteochondritis dissecans is a condition in which a bone or cartilage in the joint loses blood supply. This condition can cause pain and also affect the mobility of the person, in general.

Overuse injuries result from repeated activities that put pressure on the knees. Activities that stress the joints like cycling, climbing stairs and jogging often leads to inflammation of the joint.

Chronic or overuse injuries include:

  • Bursitis – caused by inflammation of the fluid-filled sacs in the joint
  • Tendinitis – inflammation of the tendons in the knee joint
  • Tendinosis – small tear in the tendons of the joint
  • Plica syndrome – results from folding of the ligaments in the knee
  • Patellofemoral pain syndrome – this is caused by overuse, injury, or problems in knee cap
  • Iliotibial band syndrome – caused by inflammation of the tissue present on the outside of the thigh

The main risk factors for knee pain are a lack of flexibility of muscles, previous injury to the joint, certain sports activities, and excess weight.

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3 Diagnosis and Treatment

A detailed history, physical examination, and imaging techniques reveal a good deal of information about the cause of knee pain. While considering the history of pain, the doctor may ask for the duration and intensity of pain, and the regular activities in a day.

The doctor may also ask to pinpoint the exact position of pain in the joint. Questions may also include lifestyle, medications, and history of medical conditions, if any.

During the physical examination, doctor press around the joint to check for swelling and tenderness in the knees. Physical examination also includes many maneuvers to check the integrity and strength of ligaments, tendons, and menisci.

This examination reveal chances of injuries to any of these parts that result in knee pain. Fluid analysis is sometimes suggested to check for deposits of crystals in the joints as seen in certain types of arthritis.

Imaging techniques are suggested based on physical examination and history of the patient. X-rays are useful in determining fractures, dislocations, arthritis changes, and structure of bursa. CT scans are ideal in the diagnosis of fractures.

Imaging techniques may not reveal the condition of soft tissues like tendons and ligaments. Magnetic resonance imaging (MRI) is used to evaluate the injuries to ligaments and tendons, although it is not so useful in detecting fractures.

Infections and other medical conditions that cause knee pain are evaluated using blood tests. This is particularly useful in the case of rheumatoid arthritis and diabetes. Treatment for knee pain depends on the actual cause of pain.

Medications are used to treat the underlying disease and pain. Medications are suggested in case of conditions like rheumatoid arthritis and gout.

Physical therapy is recommended to strengthen the muscles around the joint. This will help in avoiding future injuries and also to improve movements around the joint.

Physical therapy usually focuses on the quadriceps muscles (muscles on the front of the thigh) and hamstring. Balancing exercises and correction of movement patterns during an activity helps to strengthen these muscles.

Injections into the joint are suggested for certain medical conditions that cause pain in the knees. Pain and inflammation due to a flare of arthritis are often treated by injecting corticosteroids directly into the joint.

Hyaluronic acid injections are used to lubricate the joint to improve movements. Platelet-rich plasma is a growth factor concentration which when injected into the joint help in relieving pain and inflammation. These injections are often suggested for a mild form of arthritis.

A surgical reconstruction is a treatment option in some cases. Arthroscopy is a surgical technique used to remove loose bodies from the joint and to repair damages in cartilage. Torn ligaments are also reconstructed using arthroscopy.

A partial replacement surgery is suggested to replace a small portion of damaged knee. In total knee replacement surgery, the damaged joint is replaced with an artificial joint.

Alternative medicine options are also available in relieving this symptom. Glucosamine and chondroitin supplements are often suggested to relieve knee pain caused by osteoarthritis.

Acupuncture is also used in relieving osteoarthritic pain. RICE mnemonic is a useful home remedy for pain causes by minor injuries – rest, ice, compress, and elevate.

In most of the cases, knee pain responds well to treatment and resolves soon. Chronic pain needs further evaluation for treating the underlying condition.

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