By the term “arthritis” we mean the inflammation of one or more joints with the main symptoms being pain, edema and stiffness. It can affect any joint in the body, but it is very common in the knee. As a result, it can limit many of your daily activities, such as walking or stair climbing. This is a serious disability and a major cause of loss of working hours for many people.

The most common forms of “arthritis” are degenerative osteoarthritis and rheumatoid arthritis. However, there are more than 100 different types of pathological conditions that can cause arthritic lesions. In recent years, it is estimated that more than 50 million people have been diagnosed with some form of arthritis in the United States.



The knee is the largest and strongest joint in the human body. It consists of the lower end of the femur (thigh), the upper end of the tibia and the patella. Bone surfaces that come in contact with each other are covered with articular cartilage, a smooth, slippery layer that protects the bones from damage, while allowing painless movement during bending and stretching. The menisci, two wedge-shaped cartilages, act as “shock absorbers” between the femur and the tibia. Their elastic properties smoothen and provide extra stability to the joint.

Finally, the knee joint is surrounded by a thin film, the synovial bursa that produces the synovial fluid, which nourishes and lubricates the articular surfaces, thus reducing frictional forces.


Knee arthritis – Osteoarthritis

The main forms of knee arthritis are degenerative osteoarthritis, rheumatoid arthritis and post-traumatic arthritis.



Osteoarthritis is the most common form of knee arthritis. It is a degenerative type of arthritis that occurs mainly in people over 50 years of age.

In osteoarthritis, the cartilage of the knee surfaces is gradually degenerated. As the cartilage collapses, the bones come into contact with each other. The procedure is accompanied by hardening of the bony surfaces beneath the cartilage, development of new bone and cartilage at the edges of the joint (osteophytes) as well as synovial fibrosis. It usually has asymmetric distribution and is often located in a single articular compartment. Moreover, in addition to wear due to friction forces, it is also associated with pathological loads. Often, there is no other systemic manifestation, but there may be signs of inflammation locally.

Αρθρίτιδα του γόνατος - Οστεοαρθρίτιδα

Rheumatoid arthritis

Rheumatoid arthritis is a chronic inflammatory disease that simultaneously affects many joints in the human body, including the knee. It manifests as symmetrical polyarthritis, which means it affects the same joint bilaterally.

In rheumatoid arthritis, the synovial membrane begins to inflame, swell and ultimately leads to knee pain and stiffness. It is an autoimmune disorder. This means that the immune system, through the inflammatory response it causes, destroys normal tissues (cartilage, ligaments and bone surfaces).


Post-traumatic arthritis

This type of arthritis is developed after knee injury. For example, a fracture involving the joint (intra-articular fracture) can cause irreparable damage to the cartilage covering the knee articular surfaces, and consequently lead to chronic arthritic lesions. Also, meniscus ruptures and ligament injuries (e.g. anterior cruciate ligament rupture) can cause instability and further damage to the knee joint, which over time leads to arthritic lesions.



Pain is the main symptom. It is usually mild initially, but progressively it gets worse over a period of months or years. The pain in the early stages is caused by strain on the joint and recedes with rest, but over time this recession is not complete. Finally, in the advanced stages, there is nocturnal pain. Stiffness is a common clinical finding. It typically occurs after periods of immobility, but gradually it progresses and worsens over time.

Edema of the joint can be intermittent due to fluid collection in the joint (knee effusion) or continuous due to thickening of the bursa and the development of osteophytes.

Finally, many patients report a feeling of knee weakness and worsening of symptoms on rainy days.


Clinical examination

During the visit, the orthopedist first receives a good family and individual history from the patient. He then performs a thorough clinical examination during which he will search for:

  • Knee joint edema and erythema (redness)
  • Knee tenderness
  • Limited range of motion of the joint
  • Joint instability
  • Creaking sounds during knee movement
  • Pain during load charging
  • Claudication when observing the patient’s gait
  • Signs of an old knee injury or scarring
  • Involvement of more joints (indication of rheumatoid arthritis)


Imaging Examinations

Radiographs: X-rays include both knees in anterior and posterior scans. The examination is performed with the patient standing up to charge the knee joint with weight.

Radiographs are initially able to give us information about asymmetric loading or possible deformities (varosity, valgosity). They are then checked for narrowing of the articular space between the femur and tibia, sclerosis and the creation of new bone at the edges of the joint (osteophytes).

Other examinations: In special cases, MRI, CT and scintigraphy can more accurately describe the condition of the bones and soft tissues of the knee.

Recently, however, a revolutionary diagnostic arthroscopy has been added to our diagnostic tools, where we can assess the exact condition of the cartilage.


Laboratory Tests

In some cases, the orthopedist may ask the patient for specific blood tests to rule out some forms of arthritis (e.g. rheumatoid arthritis).



To date, there is no drug that modifies the course of arthritic lesions. That is why the treatment is mainly relieving and symptomatic.


Conservative (Non-Surgical) Treatment of Knee Osteoarthritis

The initial treatment of knee osteoarthritis is conservative. The treating physician may recommend a number of different therapeutic methods.


Lifestyle modification

Some changes in daily life can protect the knee joint and slow down the progression of lesions.

  • Minimize activities that worsen the symptoms, such as climbing stairs.
  • Switch from high-demand activities (running, tennis) to lower-demand (swimming) activities
  • Weight loss can reduce the daily strain of the knee joint, thus relieving the symptoms of pain and stiffness.



Some exercises can help increase the range of motion and flexibility of the joint, as well as strengthen the muscles that move the knee. The orthopedist and physiotherapist can develop a personalized exercise program that corresponds to the needs and lifestyle of each patient.


Auxiliary devices

The use of a walking cane, footwear with shock-absorbing inserts and various knee splints can be helpful. In particular, the knee splints assist the patient by providing stability to the joint, especially when the lesions cover part of the joint.


Medicines (Pharmaceutical Treatment)

Various types of medications can be used in the treatment of knee osteoarthritis.

Non-opioid analgesics and anti-inflammatory drugs are usually the drugs of choice for treating the symptoms of arthritis. These are formulations that do not require a prescription, but like all medicines they can cause side-effects and interact with other medicines.

Another type of painkillers is the non-steroidal anti-inflammatory drugs (NSAIDs). In particular, selective COX-2 inhibitors are a new type of NSAIDs that can cause less gastrointestinal side-effects. Through their anti-inflammatory effect, they relieve the patient’s pain, allowing them to return to their daily activities.

Corticosteroids (more commonly known as cortisone) are potent anti-inflammatory substances that are infused intra-articularly. These injections provide relief to the patient’s pain. However, the results do not last indefinitely. Usually, three or four injections per year are recommended, mainly because of possible side-effects. In some cases, the pain and edema may worsen after injection, and there may be long-term damage to the joint or infection. Frequent, repeated intra-articular injections can accelerate the lesions rather than reduce them.

In addition to cortisone, injections may include high viscosity substances, such as hyaluronic acid, which can alleviate the patient’s symptoms or injection of hyaluronic acid and chondroitin. During this procedure, if there is a fluid collection in the knee joint, it is aspirated prior to injection of hyaluronic acid. Following the infusion, a local reaction with edema, pain and redness may be observed. Stem cell infusion works well in younger people suffering from knee osteoarthritis.


Knee Osteoarthritis Surgery

Extensive articular damage with increased pain that cannot be treated conservatively requires surgery. As with all surgeries, there are some risks and potential complications that the orthopedic surgeon must explain to the patient. Nowadays with the new methods of regional anesthesia and the anesthetic infusion pumps post-operatively, during the first 24 hours, the patient undergoing osteoarthritis surgery experiences almost no pain.


Arthroscopy – Arthroscopic Knee Washout

During arthroscopy, small incisions and thin tools are used to diagnose and treat specific conditions. As for arthritic knee lesions, the arthroscopic method has no particular application. In cases where osteoarthritis is accompanied by degenerative lesions or meniscus ruptures, they are treated arthroscopically. The result after knee arthroscopic surgery is best when pre-selected with diagnostic arthroscopy in the physician’s office.


Osteochondral autologous grafts

Small cartilage defects can be treated by isolating small pieces of healthy cartilage from non-charged knee surfaces and implanting it at the site of injury.



The bursa, which surrounds the joint, is inflamed, especially in rheumatoid arthritis. Therapeutically, a bursectomy – open or arthroscopically – can be performed by removing any osteochondral free particles.



Osteotomy is used in the early stages of osteoarthritis, when the degeneration involves only a part of the knee. Osteotomy corrects the axis of weight-charging, as well as any deformities (knee valgosity and varosity). By shifting the weight from the damaged side of the joint to healthy tissue, the patient is relieved from pain and the functionality of the knee is significantly improved.


Total Knee Arthroplasty or Partial Unicompartmental Knee Arthroplasty

With total knee arthroplasty and unicompartmental knee arthroplasty, degenerated knee surfaces are removed and replaced with artificial prostheses, metal alloys and special plastics, to restore physiological function. Sometimes the unicompartmental knee arthroplasty is facilitated by robotic navigation – known as robotic knee arthroplasty. Care should be taken to make a differential diagnosis of knee osteonecrosis.


Postoperative Recovery / Rehabilitation

After any knee surgery, a period of recovery follows. The time of recovery and rehabilitation depends on the type of surgery being performed. The orthopedist may recommend physiotherapy, so that the patient can regain the strength and range of motion of their joint. In addition, depending on the procedure, a splint, a walking cane or a stroller may be needed for the first few days, so that the patient can return gradually and with the least possible pain to their daily activities.