What Is Knee Pain?

Do you suffer from knee pain? How can you tell if that pain is likely short-lived or a pattern of chronic pain that requires attention? Our post touches on the major causes of knee pain, such as nerve damage in the knee and degenerative conditions, along with treatments you can use to find relief.

Nerve damage can lead to knee pain, especially from injuries. Knee tissues may also be subject to degeneration, or wear and tear. This may result from everyday activity or from more extensive exertion such as athletic activity. This degeneration may be related to a case of knee pain. Pain may also be associated with many variables or risk factors. These may include:

  • Trauma
  • A result of accidental injury
  • Infections in the joint

Events such as these may be a source of acute (or sudden-onset and usually temporary) pain, but may also increase the risk of chronic (persistent and possibly long-term) knee pain in the future. An exact cause of knee pain may be difficult to detect, as some types of pain may be a symptom of many different conditions and disorders that affect this joint.

The following video gives a brief overview of knee pain causes and treatments, but we’ll talk about these in more detail throughout this post.

Anatomy Of The Knee

The knee is a large and important joint in the body. It is composed of muscles, ligaments, cartilage, fascia, and tendons that connect, support, and protect the juncture of the end of the femur (or thighbone) and the bones of the lower leg. Knee pain is a relatively prevalent condition that may be related to damage or trauma in one or some of these tissues. The knee also has a bone in front of it, the kneecap, which is a unique feature among human joints. The ligaments of the knee are present to connect one bone to another. Therefore, these are vital parts of the joint and are also vulnerable to damage.

The knee joint is also attached to various muscles, via tendons. These muscles include the quadriceps and the muscles commonly known as the hamstrings (which is also the common name for the tendon that attaches these to the joint). The knee joint is reinforced by thick layers of cartilage from within. This material helps to keep the femur and the tibia of the lower leg apart, and protect the knee from stresses and shocks. The knee is also surrounded by synovial fluid, which is contained in sacs called bursae. Pain in the knee joint may be associated with any of the structures mentioned above.

The anterior cruciate ligament (or ACL) can be found under the femur. It is an important ligament that connects this bone with the tibia. This ligament is attached to a point toward the front of the upper tibia, and then crosses the interior of the knee joint to attach to a point to the rear of the lower femur. Conversely, the posterior cruciate ligament (PCL) is attached to the rear of the tibia and more to the front of the femur. The cross-like shape this forms supports the knee joint, and ensures that the bones stay apart. This contributes to the free and optimal movement of the joint. The ACL and PCL are surrounded by the meniscus, which protects and supports these ligaments to a certain extent. The medial and lateral collateral ligaments connect the tibia and femur on either sides of the joint.

Knee Pain Prevalence

Some research suggests that the number of new knee pain complaints in women have doubled over 20 years, and that the complaints in men have tripled over the same length of time. Most of these male patients were non-Hispanic Caucasian or of Mexican origin. The majority of the female patients were of African or Mexican origin. These statistics were not affected by age or body mass index. Other estimates suggest that episodic or chronic knee pain resulting in impaired joint stability and motion and decreased life quality is present in approximately 25% of all adults.

The condition most commonly associated with knee pain in patients of 50 years or more is osteoarthritis (the effects of which are shown below). This may be associated with relative reductions in activity in this age group. The incidence of knee replacement surgery, particularly in those aged 65 or more, has also gone up recently. These procedures are performed to address chronic knee pain or dysfunction of the joint. These surgeries are also occasionally required in younger patients. Estimates indicate that approximately four million U.S. adults have needed total knee replacement. Approximately 37.5% of these are in the 50-69 year age bracket. Pain after a total knee replacement surgery is, unfortunately, also common and may be another source of knee pain for many.

Osteoarthritis As Knee Pain Cause | PainDoctor.com

Besides older adults, athletes may also be at higher risk of knee pain resulting from trauma (i.e. due to accidents or other injuries). Damage to cartilage and fascia may result from activities such as running, cycling, aerobics, and general sporting activity. Dislocations of the kneecap are prevalent among teenage girls of 13 to 18 years, which may also be associated with athletic activity. Those (particularly males) of ten to 15 years may be susceptible to osteochondrosis of the knee, which can also result in pain.

Knee Pain Causes

Knee pain can have many different types of causes, including:

  • Any trauma, injury, fracture, sprain, or strain
  • Repetitive movement injuries
  • Inflammatory conditions, such as arthritis

Let’s take a look at each of these in more detail.

Knee pain caused by trauma

Pain in the knee as a result of trauma or injury is typically related to adverse events such as:

  • Blunt force
  • Sprains or strains (i.e. twisting or other abnormal stress acting on tendons or ligaments)
  • Falling onto the knee joint
  • Atypical motions, such as excessive twisting or bending of the joint

Inadvertent excessive rotations or twisting of the knee joint increases the risk of damage to the meniscus. Knee injuries may also be associated with occupational hazards, e.g. injuries at work.

More severe types of trauma include kneecap fractures, or fractures in the bones of the leg (i.e. the tibia, fibula or femur), as they meet to form the joint.

Damage to these bones may also result from the adverse events as listed above. These injuries can result in acute pain and damage to the nerves or blood vessels found in the knee. This may result in neurological abnormalities such as loss of sensation in the joint or nerve damage that leads to knee pain in the future. Kneecap dislocation may be associated with intense pain. This injury can result in the formation of small shards of bone, which may migrate within the joint, resulting in further pain. Dislocation of the kneecap should be addressed with acute medical care.