Knee pain is pain in or around the knee.
The knee joint consists of an articulation between four bones: the femur, tibia, fibula and patella. There are four compartments to the knee. These are the medial and lateral tibiofemoral compartments, the patellofemoral compartment and the superior tibiofibular joint. The components of each of these compartments can experience repetitive strain, injury or disease.
Running long distance can cause pain to the knee joint, as it is a high-impact exercise.
The location and severity of knee pain may vary, depending on the cause of the problem. Signs and symptoms that sometimes accompany knee pain include:
Swelling and stiffness
Redness and warmth to the touch
Weakness or instability
Popping or crunching noises
Inability to fully straighten the knee
Causes
Injuries
Some common injuries based on the location include:
Sprain (Ligament sprain) Medial collateral ligament Lateral collateral ligament Anterior cruciate ligament Posterior cruciate ligament Tear of meniscus Medial meniscus Lateral meniscus Strain (Muscle strain) Quadriceps muscles Hamstring muscles Popliteal muscle Patellar tendon Hamstring tendon Popliteal tendon Hemarthrosis – Hemarthrosis tends to develop over a relatively short period after injury, from several minutes to a few hours.
Fractures
Femoral fracture
Tibial fracture
Patella fracture
Diseases
Some of the diseases of cause of knee pain include the following: Knee osteoarthritis Chondromalacia patella Baker's cyst Meniscal cyst Discoid meniscus Osgood-Schlatter disease Larsen-Johansson disease Knee rheumatoid arthritis Osteochondritis dissecans disease Synovial chondromatosis disease Tumors Ankylosing spondylitis Reactive arthritis Tuberculosis arthritis Septic arthritis (Pyogenic arthritis) Osteomyelitis Hemophilic arthritis Gout (Gouty arthritis) Neuroma
Inflammations
Bursitis of the knee
Prepatellar bursitis - Housemaid's knee (most common) Infrapatellar bursitis - Clergyman's knee (Superficial infrapatellar bursitis and Deep infrapatellar bursitis) Semimembranosus bursitis Tendinitis Patellar tendinitis (Jumper's knee) Hamstring tendinitis Popliteal tendinitis Synovitis of the knee
Deformities
Common deformities of the knee include: Bipartite patella (two-part kneecap) Genu varum (bow legs) Genu valgum (knock-knees) Genu recurvatum (Knee hyperextension) Knee flexion deformity
Syndromes
Patellofemoral pain syndrome
Plica syndrome
Iliotibial band syndrome
Hoffa's syndrome
Joint hypermobility syndrome
Dislocations
Patella dislocation
Knee joint dislocation (Tibiofemoral joint dislocation)
Cold temperature
Knee pain is more common among people working in the cold than in those in normal temperature. Cold-induced knee pain may also be due to tenosynovitis of the tendons around the knee, in which cold exposure has a specific role, either as a causative or a contributing factor. Frank arthritis has been reported in children due to frostbite from extreme cold causing direct chondrocyte injury.
There is also a hereditary disease, familial cold autoinflammatory syndrome (FCAS), which often features knee pain, in addition to hives, fever and pain in other joints, following general exposure to cold.
Knee pain due to less physical movement
A lower level of physical activity and a work environment where one is required to sit in a chair during the work day is one reason for developing knee joint pain, as the lower degree of physical movement tends to weaken the knee muscles. Blood vessels also can be affected, leading to development of painful conditions. Working on building strength through a full range of motion is crucial for rebuilding strength and getting rid of knee pain.
As age progresses the movement of the knee joint involves higher friction with adjacent tissue and cartilages.
Other causes
Ligamentous laxity
Fat pad impingement
Knee effusion
Deep vein thrombosis
Peripheral vascular disease
Exostosis
Referred knee pain
Referred pain is that pain perceived at a site different from its point of origin but innervated by the same spinal segment. Sometimes knee pain may be related to another area from body. For example, knee pain can come from ankle, foot, hip joints or lumbar spine.
Diagnosis
Knee MRIs should be avoided for knee pain without symptoms or effusion, unless there are non-successful results from a functional rehabilitation program.