Knee arthrosis: what is it, causes, symptoms, treatment

What is knee arthrosis?

Knee arthrosis, also known as osteoarthritisknee joint or gonarthrosis usually results from wear and tear and progressive loss of articular cartilage. It is most common in older women and men. Knee arthrosis can be divided into two types: primary and secondary. Primary osteoarthritis is joint degeneration without any obvious cause. Secondary osteoarthritis is a consequence of either post-traumatic causes or diseases that destroy articular cartilage, for example, rheumatoid arthritis (RA).

Osteoarthritis (osteoarthritis) is usually a progressive disease that can eventually lead to disability. The intensity of clinical symptoms can vary from person to person. However, over time, symptoms usually become more severe, frequent, and debilitating. The rate of their progression also varies. Common clinical symptoms include knee painthat starts gradually and gets worse with physical activity, stiffness and swelling of the knees, pain after prolonged sitting or rest and that gets worse over time.

Treatment of osteoarthritis of the knee begins with conservative methods and moves on to surgical options if conservative treatment fails. Although medications can help slow the progression of RA and other inflammatory conditions, There are currently no proven disease-modifying agents for the treatment of arthrosis of the knee joint.

Signs and symptoms

The main symptom of gonarthrosis is pain, causing loss of ability and often stiffness. The pain usually increases with prolonged physical activity and decreases at rest. Stiffness most commonly occurs in the morning and usually lasts less than thirty minutes after starting daily activity, but may return after periods of inactivity. Osteoarthritis of the knee can cause a crunching sound (called "crepitus") when the affected joint moves. The person may also complain of joint blockage and instability. These symptoms can interfere with daily activities due to pain and stiffness. Some patients report increased pain associated with low temperature, high humidity, or a drop in barometric pressure, but studies have produced mixed results.

Causes and risk factors

Knee osteoarthritis is classified as either primary or secondary, depending on its cause. Primary arthrosis of the knee is the result of degeneration of the articular cartilage without any known cause. This is usually considered to be degeneration due to age as well as wear and tear. Secondary arthrosis of the knee is the result of degeneration of the articular cartilage for a known reason.

Possible causes of secondary arthrosis knee joint:

• Post-traumatic;
• Postoperative;
• Congenital or acquired deformity of the limb;
• Hallux valgus or varus deformities;
• Scoliosis;
• Rickets;
• Hemochromatosis (pigmented cirrhosis, bronze diabetes);
• Chondrocalcinosis;
• Ochronosis;
• Wilson-Konovalov disease (hepatocerebral dystrophy, hepatolenticular degeneration);
• Gout;
• Pseudogout;
• Acromegaly;
• Avascular necrosis;
• Rheumatoid arthritis;
• Infectious arthritis;
• Psoriatic arthritis;
• Hemophilia;
• Paget's disease;
• Sickle cell anemia.

Risk factors for arthrosis of the knee joint

Triggers that can be influenced:

• Joint injury;
• Occupation - prolonged standing and repetitive bending of the knees;
• Muscle weakness or imbalance;
• Obesity;
• Health - metabolic syndrome.

Triggers that cannot be influenced

• Gender - women are affected more often than men;
• Age;
• Genetics;
• Race.

Epidemiology

Knee arthrosis is the most common type of diagnosed osteoarthritis, and its prevalence will continue to increase as life expectancy and obesity increase. Depending on the source, approximately 13% of women and 10% of men aged 60 and over have symptomatic osteoarthritis of the knee. Among people over 70, the prevalence reaches 40%. The prevalence of osteoarthritis of the knee joint in men is also lower than in women. Interestingly, not everyone who shows X-ray signs of knee arthrosis will have symptoms. One study found that only 15% of patients with radiographic signs of knee arthrosis had symptoms. Excluding age, the incidence of symptomatic illness is approximately 240 cases per 100,000 population per year.

Pathophysiology

Articular cartilage is composed primarily of type II collagen, proteoglycans, chondrocytes, and water. Healthy articular cartilage constantly maintains a balance between each of the components, so any destruction of cartilage is accompanied by synthesis. In this way, healthy articular cartilage is preserved. During osteoarthritis, matrix metalloproteinases (MMPs) or degrading enzymes are overexpressed, disrupting equilibrium and leading to a general loss of collagen and proteoglycans. In the early stages of osteoarthritis, chondrocytes secrete tissue MMP inhibitors (TIMPs) and try to increase proteoglycan synthesis to match the degradation process. However, this restorative process is not enough. Imbalance leads to a decrease in the amount of proteoglycans, despite the increased synthesis, increased water content, impaired collagen structure and, ultimately, loss of elasticity articular cartilage. Macroscopically, these changes lead to cracking and rupture of the cartilage and, ultimately, to erosion of the articular surface.

Although arthrosis of the knee is closely related to aging, it is important to note that arthrosis of the knee is not just a consequence of aging, but rather its own disease. This is supported by the differences observed in cartilage in both osteoarthritis and aging. Moreover, the enzymes responsible for cartilage degradation are expressed in higher amounts when osteoarthritis of the knee joint, whereas in normal aging cartilage they are on normal level.

Diagnostics

Diagnosis is made with reasonable certainty based on history and clinical examination. X-rays can confirm the diagnosis. Typical changes seen on an x-ray include: narrowing of the joint space, subchondral sclerosis (increased bone formation around the joint), the formation of subchondral cysts and osteophytes. Regular imaging may not correlate with the findings of the physical exam or the degree of pain. Usually, other imaging techniques are not needed for the clinical diagnosis of osteoarthritis.

Treatment

Treatment of arthrosis of the knee joint can be divided into non-surgical and surgical. Initial treatment starts with non-surgical methods and moves on to surgical treatment when non-surgical methods are no longer effective. A wide range of non-surgical methods are available for the treatment of arthrosis of the knee. These interventions do not alter the underlying disease process, but can significantly reduce pain and disability.

- Non-surgical treatment options.

• Modification of activities
• Physiotherapy
• Weight loss
• Knee fixation
• Acetaminophen
• Non-steroidal anti-inflammatory drugs (NSAIDs)
• COX-2 inhibitors
• Glucosamine and Chondroitin Sulfate
• Corticosteroid injections
• Hyaluronic acid (HA)

First-line treatment for all patients with symptomatic osteoarthritis of the knee includes patient education and physical therapy. A combination of supervised exercise and a home exercise program has been shown to produce the best results. These benefits are lost after 6 months if you stop exercising.

Losing weight is valuable at all stages of knee osteoarthritis. It is indicated for patients with symptomatic arthrosis with a body mass index of more than 25. The best recommendation for achieving weight loss is diet control and low-impact aerobic exercise. There is moderate evidence for weight loss based on AAOS guidelines (i.e. American Academy of Orthopedic Surgeons).

In osteoarthritis, a knee orthosis is useful in a situation where the lateral or medial knee is affected, for example, with valgus or varus deformity.

Drug therapy is also the first line treatment for patients with symptomatic osteoarthritis. A wide variety of non-steroidal anti-inflammatory drugs are available and selection should be based on physician preference, patient acceptability, and cost. The duration of NSAID treatment should depend on the effectiveness, side effects, and medical history.

Glucosamine and chondroitin sulfate are available as dietary supplements. They are the structural components of articular cartilage and the supplement is believed to help maintain the health of articular cartilage. There is no conclusive evidence that these supplements are helpful for gonarthrosis. There are no major drawbacks to taking the supplement. If the patient understands the evidence behind these supplements and is willing to try them, this is a relatively safe option. Any benefit from supplementation is likely to be related to the placebo effect.

Intra-articular injections corticosteroids can be useful in symptomatic arthrosis of the knee joint, especially in the presence of a significant inflammatory component. Delivery of the corticosteroid directly to the knee can reduce local inflammation associated with gonarthrosis and minimize the systemic effects of the steroid.

Intra-articular injections of hyaluronic acid (HA) are another injection option for osteoarthritis of the knee joint. HA is a glycosaminoglycan found throughout the body and is an important component of synovial fluid and articular cartilage. HA is destroyed during osteoarthritis and contributes to the loss of articular cartilage as well as stiffness and pain. Local delivery of HA to the joint acts as a lubricant and may help increase the natural production of HA in the joint. Depending on the brand of HA, it can be produced from either bird cages or bacterial cells in the laboratory, so it should be used with caution if you are allergic to birds. Although it is a common treatment option, it has not received widespread support in the literature and there is strong evidence against its use based on the AAOS guidelines.

- Surgical treatment options.

• Osteotomy
• One-Piece Knee Arthroplasty (OAKS)
• Total Knee Replacement (TKR)

High tibial osteotomy (HTO) may be indicated for single-component knee osteoarthritis associated with displacement. Usually VTO is performed for varus deformities, when the medial part of the knee is worn out and has arthritis. The ideal patient for an OBE would be a young, active patient whose arthroplasty will fail due to excessive wear on the components. VTO ​​preserves the knee joint, including the cruciate ligaments, and allows the patient to return to active activity after recovery. It requires additional healing time compared to arthroplasty, is more susceptible to complications, depends on healing bones and fractures, is less reliable for relieving pain and, ultimately, does not replace already lost cartilage and does not restore the remaining cartilage. An osteotomy will delay the need for arthroplasty for up to 10 years.

Indications for WTO

• Young (under 50), active patient
• Healthy patient with good vascular status
• Non-obese patients
• Pain and disability interfere with daily life
• Only one knee compartment affected
• A patient who can follow the postoperative protocol

Contraindications for WTO

• Inflammatory arthritis
• Obese patients
• Contracture of knee flexion over 15 degrees
• Knee flexion less than 90 degrees
• If the procedure requires a deformity correction of more than 20 degrees
• Patellofemoral arthritis
• Knee ligament instability

OAC is also indicated for single-component knee osteoarthritis. This is an alternative to the WTO and TECS. It is indicated for elderly patients, usually 60 years of age or older, and relatively thin patients.

Indications for OAKS

• Elderly (60 years and older) patients.
• Relatively thin patients.

Contraindications for OAKS

• Inflammatory arthritis
• ACL deficiency
• Fixed varus deformity of more than 10 degrees
• Fixed hallux valgus more than 5 degrees
• Flexion contracture over 10 degrees
• Arthritis in more than one area
• Younger, more active patients or harder workers
• Patellofemoral arthritis

TEKS is a surgical option for patients who have not been helped by conservative treatment and patients with osteoarthritis in several departments. The method is considered a valuable intervention for patients who experience severe daily pain along with radiographic evidence of knee arthrosis.

Indications for TEKS

• Symptomatic osteoarthritis of the knee in more than one compartment
• Unsuccessful non-surgical treatment options

Contraindications for TEKS

Absolute

• Active or latent knee infection
• Having an active infection in other parts of the body
• Quadriceps or extensor failure

Relative

• Neuropathic arthropathy
• Poor soft tissue coverage
• Morbid obesity
• Serious mental health problems, alcohol or drug abuse
• Insufficient bone supply for reconstruction
• Poor health or underlying medical conditions that make the patient unsuitable for major surgery and anesthesia.
• Poor patient motivation or unrealistic expectations
• Severe peripheral vascular disease

Advantages of OAKS over TEKS

• Faster rehabilitation and faster recovery
• Less blood loss
• Less morbidity
• Less expensive method
• Maintaining normal kinematics
• Less postoperative pain and shorter hospital stays

Advantages of OACC over WTO

• Faster rehabilitation and faster recovery
• Higher initial success
• Less short term complications
• Lasts longer

Complications

Complications associated with non-surgical treatment are largely associated with the use of NSAIDs.

Common side effects of taking NSAIDs

• Stomach pain and heartburn;
• Stomach ulcer;
• Bleeding tendency, especially when taking aspirin;
• Kidney problems.

Common Side Effects of Intra-articular Corticosteroid Injections

• Pain and edema;
• Discoloration of the skin at the injection site;
• Elevated level blood sugar;
• Infection;
• Allergic reaction.

Common side effects of intra-articular hyaluronic acid injections

• Pain at the injection site;
• Muscle pain;
• Trouble walking;
• Heat;
• Chills;
• Headache.

Complications associated with high tibial osteotomy

• Recurrence of deformity;
• Loss of posterior tibial tilt;
• Compartment syndrome;
• Peroneal nerve paralysis;
• Infection;
• Constant pain;
• A blood clot (thrombus).

Complications associated with one-piece knee arthroplasty

• Tibia stress fracture;
• Collapse of the tibial component;
• Infection;
• Osteolysis;
• Constant pain;
• Neurovascular injury;
• Thrombus.

Complications associated with total knee arthroplasty

• Infection;
• Osteolysis;
• Neurovascular injury;
• Fracture;
• Extension mechanism rupture;
• Violation of the patella track;
• Patellar entrapment syndrome;
• Stiffness of movement;
• Peroneal nerve paralysis;
• Complications in the wound;
• Heterotopic ossification;
• Thrombus.