Swollen knee pain is an unpleasant feeling experienced due to swelling in the knee with excessive fluid accumulation in the intra-articular space and bursae of the joint. Depending on the cause and extent of damage to the joint, the pain is either generalized or localized. It restricts the degree of knee movement, troubling the patient to bear weight and walk around.
Patients with generalized pain fail to identify the affected area. Hence, a detailed diagnosis is crucial to identify the root cause and determine the treatment options that yield the best outcome. That said, there are several causes of swollen knee pain. Let’s discuss them in detail below.
Causes of Swollen Knee Pain
There are many reasons behind swollen knee pain that you must know. Let’s look at them one by one.
- Ligament Sprains and Tears
Ligament tear due to injury causes sudden pain and swelling. These ligament tears are divided into lateral and collateral ligament injuries, which are divided into three grades.
- Grade 1 tear causes localized lateral knee tenderness but not swelling.
- Grade 2 injury, also called partial tear, leads to 5 to 10 mm of laxity, but endpoints of the ligament remain fixed.
- Grade 3 injury (a complete tear) loosens the ligament for longer than 10 mm. The swelling and pain intensity varies among the patients.
- Meniscal Tears
Meniscal tears due to injury are common in sports persons and occur at the time of hyperextension and twisting movements and actions of great force. The swelling due to meniscal tears results from the imbalance between pro- and anti-inflammatory activities in the synovial fluid surrounding the meniscus.
Fractures can happen when the knee experiences a sudden impact, causing it to hyperextend and disrupt its structural stability. It can cause bleeding from the ligaments and bones, entering the synovial fluid and leading to knee swelling.
Another reason for knee swelling following a knee injury is known as sympathetic effusion. It occurs when non-inflammatory fluid accumulates in the cavity near the site of inflammation.
Medical Conditions Causing Swollen Knee Pain
Besides the causes discussed above, many medical conditions can cause swollen knee pain. Let’s look at them one by one below.
It is the most common form of arthritis affecting the knee tissue. The disease begins at the articular cartilage and extends to the collagen matrix and bone. The cartilage outgrowths and thickening of bones lead to swollen knee pain. Additionally, synovial inflammation and hypertrophy contribute to the progression of swelling.
- Rheumatoid Arthritis
It is an autoimmune disorder wherein the immune cells primarily target the synovial membrane and go deep as the disease progresses. Other histopathological changes that contribute to the hypertrophy of synovium are increased vascularization and fibrin deposition. The swelling causes stiffness and intense pain affecting knee movement.
Gout is an inflammatory disorder caused by tissue deposition of the rod or long needle-shaped monosodium urate crystals. The deposits cause inflammation in the prepatellar bursa in front of the kneecap leading to swelling and pain.
The inflammation of the bursae that form cushions between the bones, tendons, ligaments, and muscles is called bursitis.
Symptoms of Swollen Knee Pain
- Common Signs and Symptoms
The following are the common swollen knee symptoms.
- Eerie Appearance: The limb appears grotesque due to swelling or inflammation.
- Stiffness: The tissue around the knee becomes constricted, inciting undesirable sensations.
- Pain: Patients feel excruciating pain while walking, doing other activities, and prolonged resting. It limits the range of motion. The intensity and tolerability vary among individuals.
- Redness and Warmth: In most cases, skin over the affected knee turns red due to inflammation. The site becomes warm due to exothermic inflammatory reactions.
- When to See a Doctor
You must see a doctor when you encounter the following swollen knee symptoms to receive medical attention.
- Inability to bear one’s weight
- Inability to extend or flex knees
- Significant deformity in a limb due to a swollen knee
- Redness around the knee.
Treatment Options for Swollen Knee Pain
R.I.C.E. (Rest, Ice, Compression, Elevation) Method
The RICE method is the most economical swollen knee management technique. It is the combination of the following four interventions
Restricting the use of the affected knee decreases the metabolic demands and diverts the energy toward innate self-healing mechanisms. It avoids stress on the tissues and disruption of bonds between fibres.
It helps reduce the temperature by placing ice over the knees to reduce metabolic needs, induce vasoconstriction, and limit bleeding. It imparts an analgesic effect by increasing the peripheral nerve conduction latency.
It stops the flood flow from damaged capillaries into the tissues and controls the swelling.
It involves positioning the affected leg in an elevated posture to reduce the bleeding. Further, it facilitates the proper flow of the inflammatory exudate through the lymphatic system.
- Over-the-Counter Pain Relievers
These medications effectively combat low pain intensity as high dosages require a prescription from certified physicians. Effective over-the-counter drugs include
- NSAIDs, such as diclofenac, ibuprofen and naproxen.
- Prescription Medications
Medication for swollen knee treatment is as follows.
- High dose of NSAIDs
- Corticosteroids, such as cortisone and prednisone.
- Hyaluronic acid
- Opioid medications like hydrocodone, morphine, oxycodone, and tramadol.
- Local anaesthetics, such as lidocaine
No matter how severe the condition is, physical therapy is often used to alleviate pain and discomfort. The therapy involves applying controlled pressure over the affected muscles and bones in different patterns. Therapists include exercises and hands-on therapy in about two or three sessions a week for a period. Further, they assess the patient for changes in the mobility of the knees.
- Corticosteroid Injections
Corticosteroids are anti-inflammatory drugs administered directly into the affected area. Additionally, it reduces swelling and pain. The procedure involves giving local anaesthesia before the injection to numb the area.
- Hyaluronic Acid Injections
A hyaluronic acid injection is a form of gel injection that reduces pain. It improves joint movement by lubricating the bones and allowing them to move smoothly in the knee.
- Knee Arthroscopy
The procedure involves making a few incisions. One is for the passage of the micro-size camera to visualize the causative anatomical deformations, and the other is for the tools required to operate the knee. The procedures are as follows.
- Reconstruction of ligament tear
- Partial meniscectomy
- Repair of a torn meniscus
- Meniscus transplantation
- Excision of inflamed synovial tissue
- Trimming or reconstructing damaged articular cartilage
- Knee Replacement
It is the choice of swollen knee pain treatment for severe injuries and degenerative conditions such as osteoarthritis. It involves capping the ends of the bones, including the kneecap, that form the joint using metal or plastic.
Regardless of the swollen knee causes, it affects the patient’s quality of life by restricting the range of motion of the lower extremities. Over-the-counter medicine can provide rapid relief from the pain and help alleviate the underlying cause without medical interventions.
But swollen knees due to chronic conditions and severe injuries need immediate medical attention for definitive prescription or disease-modifying drugs. On the other hand, surgical interventions are reserved for extreme cases that do not respond to medications.