KNEE OSTEOARTHRITIS

KNEE OSTEOARTHRITIS
DR. JORDI JIMÉNEZ

Knee osteoarthritis ( gonarthrosis) is a disease characterized by the gradual loss of articular cartilage, combined with thickening and hardening of the subchondral bone and the appearance of deformities at the joint margins (osteophytes). It may also be associated with chronic inflammation of the synovial membrane. The knee has three compartments: the medial and lateral femoro -tibial, and the femoro -patellar. These compartments can be affected either in isolation or together.

We are aware that it is the most common joint disease in humans, strongly related to age, and the main cause of mobility impairment, especially in women. We specialize in solutions that allow people to recover their quality of life.

Osteoarthritis can be divided into primary (idiopathic) and secondary forms. Primary osteoarthritis has a nonspecific cause, as it is multifactorial. It can be localized or generalized. Localized primary osteoarthritis affects only one joint and is common in the hands, feet, knees, hips, and spine. In contrast, generalized primary osteoarthritis affects two or more joints. Secondary osteoarthritis occurs due to specific conditions that can directly cause the condition or be a significant risk factor for its development: trauma, congenital diseases, metabolic diseases, rheumatic diseases, etc.

Origin of Knee Osteoarthritis

The specific onset of osteoarthritis is still unclear, although local, systemic, genetic, and environmental factors are known to influence it. It has been proven that increased pressure on articular cartilage causes alterations in its extracellular matrix. Over the years, the ligaments around the joint become more lax, causing instability. This ultimately contributes to an abnormal distribution of pressure on the cartilage, thus generating stress that triggers the disease.

Osteoarthritis can also be caused by changes in the structure of the subchondral bone (the bone beneath the articular cartilage). If the joint is repeatedly affected by microtrauma , these can cause microfractures in the subchondral bone, thereby altering the biomechanical quality of the cartilage surrounding the fracture sites. These changes in the cartilage can cause the bone to synthesize growth factors, which can result in the production of osteophytes or osteosclerosis.

Epidemiological studies on the prevalence of osteoarthritis in postmenopausal women suggest that one or more hormonal factors are involved in the onset of the disease.

Osteoarthritis was previously thought to be a normal consequence of aging, and was therefore considered a pathology that caused joint degeneration. Today, we know that osteoarthritis arises from a combination of different factors:

Age: It is the most important risk factor for osteoarthritis.
Female sex: It is thought to be related to hormones, genetics and other undetermined factors.
Obesity: It is the most modifiable risk factor for the development of osteoarthritis.
Occupation: The degree of occupational impact will vary depending on the type of occupation and the joint most affected by this work.
Sports activities: These activities will be a risk factor whenever the activity directly affects the joint, and will vary depending on the joint and the type of sport.
Previous injuries: Previous injuries, metabolic diseases, and/or joint abnormalities increase the development of osteoarthritis. Injuries can occur both in the joint and in the surrounding areas. Meniscus abnormalities are common in patients with osteoarthritis.
Muscle weakness: In the case of knee osteoarthritis, quadriceps muscle weakness may be etiologically related to the onset or progression of osteoarthritis in some patients.
Genetic load (Inheritance)

Osteoarthritis is the most common joint disease in humans. It is also a focal joint disease because, unlike inflammatory arthropathies, it does not always affect the entire joint. For example, in the knee, the most commonly affected areas are the medial femorotibial and lateral patellofemoral compartments.

Manifestations of knee osteoarthritis

The manifestations of knee osteoarthritis are varied and depend on the degree of involvement. It is usually characterized by limited joint movement; stiffness after a period of inactivity, especially in the morning; joint crepitation (rubbing and creaking); subchondral bone sclerosis; formation of bony protuberances or marginal osteophytes; joint instability; presence of edema; and joint pain, especially after exercise. Valgus or varus deformity of one or both knees may also occur, although this would be a late phenomenon in the natural history of the disease. A narrowing of the medial and/or lateral femorotibial joint space may also occur , and in more advanced cases, subchondral cysts and secondary malalignment may be present .

Knee osteoarthritis is suspected in any patient who experiences persistent knee pain lasting more than 30 days, which increases with physical activity (lifting weight, climbing or descending stairs) and decreases with rest. Other factors that may lead to a suspected diagnosis of knee osteoarthritis include:

Morning joint stiffness
Pain that is usually more important at the beginning of walking.
Insidious installation in time.
Joint deformity.
Contracture or stiffness of the affected joint.
Crepitation upon joint mobilization.
Cold or non-inflammatory joint effusion.

Diagnosis of knee osteoarthritis

Clinical elements alone may be used to establish a diagnosis, or laboratory studies may also be used.

Complementary exams

Plain X-ray.
Computed axial tomography (CT) can also be very useful.
Magnetic resonance imaging is the most sensitive and specific technique for osteoarthritis, as it displays soft tissues such as cartilage as well as bone. It allows for the detection of early degenerative changes and periarticular and bone complications, making it very useful when a diagnosis is uncertain.
Synovial fluid examination: If there is increased synovial fluid in the knee, a sample may be taken for analysis (arthrocentesis). In the case of osteoarthritis, the synovial fluid will be clear, transparent, or slightly yellowish, with a normal thickness of 3 cm, and may contain crystalline salts.

Due to its similar symptoms to osteoarthritis, it can be confused with other pathologies, including calcium pyrophosphate crystal deposition disease, rheumatoid arthritis, and septic arthritis.

Make an appointment with Dr. Jordi Jiménez. He'll see you in the center of Palma and help you regain your quality of life.