Knee arthritis: symptoms, causes and treatment

Medically reviewed: 15, February 2024

Arthritis of the knee joint: symptoms, treatment medication, causes

Knee arthritis is a degenerative-dystrophic disease of connective tissue that affects the joint apparatus in conjunction with adjacent tissues and auxiliary structures.

Arthritis of the knee is a common degenerative disease of the musculoskeletal system.

Arthritis is characterized by:

• chondritis – inflammation of articular cartilage;
• osteitis – inflammatory changes in bone structures adjacent to cartilaginous tissues;
• synovitis – inflammation of the joint bag;
• inflammatory changes in soft tissues and ligamentous apparatus in the projection of the joint.

In the structure of degenerative joint diseases arthritis of the knee joint occupies a predominant position: it is diagnosed in approximately 10-20% (in certain age groups – up to 80%) of the population of mature and elderly age (women are sick twice as often), accounting for one third of all osteoarthroses.

By 2020, the number of patients with arthritis of the knee joint is expected to double, which is associated with increased loads and aging of the population.

Every 8 out of 10 people suffering from this disease note a significant deterioration in the quality of life, in 2 out of 10 it leads to the formation of disability.

Synonyms:

• gonarthritis,
• gonarthrosis,
• osteoarthritis or osteoarthrosis of the knee,
• deforming osteoarthritis.

Causes of the Knee Arthritis

Gonarthritis, like any other degenerative joint disease, develops as a result of an imbalance between the processes of synthesis and degradation in the cartilaginous and adjacent bone tissues, resulting in the destruction of the cartilage.

If the normal processes of neoplasm prevail, then in arthritis this equilibrium shifts towards the growth of degeneration and subsequent degeneration of tissues. Initial changes at the cellular level lead to a disruption of tissue hemostasis, the fine structure of the cartilage of the knee joint is modified (foci of opacification, thinning and defibration, microcracks and ruptures).

In view of the ongoing structural rearrangements, the cartilage loses elasticity, its depreciation function suffers, the mutual disposition of the articulating surfaces is disrupted, aggravating the degradation.

Compensatory, in response to the thinning of the cartilaginous layer, the compaction and proliferation of the adjacent bone tissue begins, bone outgrowths, spines, complicating the adequate functioning of the knee joint and aggravating the course of the disease.

In addition to the theory of the development of arthritis of the knee joint, in which the degenerative changes in the articular cartilage play a fundamental role, there is an assumption about the primary lesion of the bone tissue of articular surfaces.

According to this concept, in the thickness of the heads of bones that form the articulation, microcirculation is disrupted, venous congestion develops, foci of intraosseous microinfarctions are formed. Against the background of blood supply disorders, the mineral content of bone tissue is depleted, its rarefaction and micro-restructuring. The spectrum of such changes can not but be reflected in the state of the nearby cartilaginous tissue, leading to its pathological changes.

Arthritis of the knee joint is diagnosed in approximately 10-20% (in some age groups – up to 80%) of the population of mature and elderly age (women are sick twice as often), making up a third of all osteoarthroses.

The main causes of arthritis of the knee joint are:

• previous injury (bruise, intra-articular fracture, rupture of ligaments, menisci, penetrating wounds of the knee joint);
• chronic traumatization (professional arthritis of the knee joint in the representatives of parachute sport, athletes,
• hockey players, football players, gymnasts, dancers, manual workers, etc.);
• suffered acute inflammatory diseases of knee joints;
• autoimmune connective tissue diseases;
• chronic diseases, in which inflammation of the knee joint is one of the symptoms (psoriasis, tuberculosis, syphilis, etc.).

How does knee arthritis develops

In addition to the acquired causes, the development of arthritis of the knee joint may be due to mutations of the gene of collagen type II (COL2A1) or VDR gene, controlling vitamin D-endocrine system, transmitted from parents to the offspring autosomally recessive or-dominantly (X-linked inheritance is not excluded).

Risk factors for arthritis of the knee joint are more often associated with increased load on the axial skeleton or with trophic disorders of the joint apparatus:

• female sex (the risk of developing gonarthritis increases in menopause);
• overweight;
• metabolic diseases;
• diseases of the vascular system, accompanied by local disturbances of blood supply, increased fragility of capillaries;
• elderly age;
• endocrine disruption;
• anomalies in the structure of the joints;
• scoliosis;
• connective tissue dysplasia;
• O- and X-shaped thigh setting (curvature of the axis of the lower limb);
  ‘flat feet;
• Conditions affecting the blood vessels in the lower limbs are referred to as diseases of the vessels of the lower extremities.

Forms of the knee arthritis

Depending on the causes, the following forms of pathology are distinguished:

• primary (idiopathic gonarthritis);
• secondary.

In accordance with an objective picture of changes in the articular apparatus, arthritis of the knee joint is classified in several ways.

X-ray classification by Albek (Ahlbäck):

• Narrowing of the joint space (less than 3 mm).
• Closure of the joint space.
• Minimal bone defect (0-5 mm).
• Moderate bone defect (5-10 mm).
• Pronounced bone defect (> 10 mm).

X-ray classification by Kellgren (Kellgren & Lawrence):

• Doubtful stage (minor osteophytes).
• The minimal stage (pronounced osteophytes).
• Moderate stage (moderate narrowing of the joint space).
• Severe stage (pronounced narrowing of the joint gap with subchondral sclerosis).

Stages of rheumatoid arthritis of the knee joint Stages of rheumatoid arthritis of the knee joint

Depending on the degree of severity:

• Compensated gonarthritis – the pain syndrome is absent or appears after an intense load, the joint is stable, its functioning is not violated;
• Subcompensated – pain syndrome is more pronounced, partial drug dependence is noted, walking aids are used auxiliary tools, there is a slight instability of the joint and a partial limitation of its functionality;
• Decompensated – a constant pain syndrome, requiring medication correction, dependence on analgesics, the need for constant orthopedic discharge (cane, crutches), the joint is unstable, its mobility is severely limited.

Stages of knee arthritis

Determination of the stage of arthritis of the knee joint is performed on the basis of an assessment of the clinical signs of the disease and the radiographic data in the aggregate:

• Minor narrowing of the joint gap, determined by radiographic examination, moderate subchondral sclerosis;
• Clinically characteristic pain after or during a load, stopping at rest, active and passive movements in the joint are preserved in full.
• The joint gap is narrowed 2-3 times, signs of pronounced subchondral osteosclerosis, single bony proliferation along the edges of the joint gap and / or in the zone of intercondylar elevation; clinically – moderate pain syndrome, limitation of mobility of the joint, gait disturbance, slight frontal deformation of the axis of the affected limb.
• The clinical picture is characterized by persistent flexion-extensor contractures, the soreness is constant, increasing with insignificant load, the change in gait is pronounced, joint instability, atrophic muscles of the thigh and lower leg are noted; radiographically – significant deformation and sclerosis of articular surfaces, local foci of rarefaction of bone tissue, articular fissure insignificantly preserved or closed, extensive bone growths and free joints are defined.

Symptoms of knee Arthritis

The most significant symptoms of the disease include:

• soreness in the projection of the affected joint;
• dysfunction of the joint;
• change the habitual stereotype of walking.

Pain in arthritis of the knee joint initially worries patients only during exercise (especially when walking uphill, downhill and climbing stairs, while doing sports, staying for a long time in a standing position) and quiet down at rest. Often soreness in the affected joint appears later in the evening, sometimes in damp, cold weather. Painful complaints are related to patients’ complaints about the need for additional support (for example, walking sticks), difficulty in trying to sit down or stand up from a chair or chair.

Arthritis of the knee joint is characterized by local soreness in palpation, especially in the projection of the joint space.

Dysfunctions are manifested by a decrease in the amplitude of both passive and active movements (initially – flexion, later and extension of the affected joint), a sense of “jamming”.

Other symptoms of knee arthritis may include:

• puffiness, local increase in temperature in the projection of inflammation;
• deformation of the affected joint;
• change in limb axis;
• lameness;
• crunch when driving;
• morning stiffness (restriction of mobility after waking, disappearing within 10-30 minutes after the onset of active movements).

Every 8 out of 10 people suffering from arthritis of the knee joint notice a significant deterioration in the quality of life, in 2 out of 10 it leads to the formation of a disability.

Arthritis of the knee joint is a chronic progressive disease having a wavy course and flowing with an alternation of periods of remission and exacerbation, which can be provoked, for example, by physical stresses or by exposure to environmental factors.

Diagnostics of Knee Arthritis

Knee arthritis affects millions of people worldwide, leading to pain, stiffness, and reduced mobility. Accurate diagnosis is crucial for effective treatment and management. This article will explore various diagnostic options available for knee arthritis, presented in an easy-to-understand manner.

Medical Terminology:

1. Arthritis: Inflammation of joints causing pain, swelling, and stiffness.
2. Osteoarthritis (OA): Degenerative joint disease due to wear and tear, mostly affecting weight-bearing joints like knees.
3. Rheumatoid Arthritis (RA): Autoimmune disorder causing chronic inflammation and potential damage to joint tissues.

Diagnosis starts with a thorough clinical evaluation involving:

• Medical History: Discuss previous injuries, symptoms, family history, and overall health status.
• Physical Examination: Check range of motion, identify tender points, assess alignment, stability, and detect crepitus (grinding sensation) upon movement.

Imaging Techniques

These methods provide visual insights into internal structures and abnormalities associated with knee arthritis.

1. X-rays: Primarily used to diagnose osteoarthritis, x-ray imaging reveals bone spurs, narrowed joint spaces, cysts, or deformities indicative of cartilage breakdown. However, soft tissue involvement may go unnoticed since x-rays don’t capture them well.
2. Computerized Tomography (CT) Scans: Combining several x-ray views taken from different angles, CT scans generate cross-sectional images offering better detail than conventional radiographs, particularly useful when complex fractures or subtle bone changes need assessment. Note that radiation exposure is higher compared to traditional x-rays.
3. Magnetic Resonance Imaging (MRI): Using radio waves and strong magnetic fields, MRIs produce high-resolution multiplanar images allowing clear visualization of bones, cartilages, ligaments, tendons, menisci, bursae, synovial membrane, and muscles around the knee joint. Therefore, MRI helps reveal early degenerative signs, fluid accumulation, lesions, infection foci, tumors, or bone marrow edema often missed in x-ray and CT examinations. Moreover, no ionizing radiation risks are involved.

Other Advanced Diagnostics

When imaging studies fall short in delivering definitive results, doctors might resort to advanced diagnostics to pinpoint specific conditions driving knee arthritis manifestation.

1. Ultrasound: Employing sound waves above human audible frequency, sonography captures real-time moving pictures enabling dynamic examination of soft tissues (such as tendons, ligaments, and bursae) near the knee, revealing any thickening, tears, or effusions efficiently. Furthermore, ultrasounds facilitate guided interventions like aspiration procedures under local anesthesia.
2. Bone Scan: Also termed radionuclide scan, this technique injects low-dose radioactive material intravenously highlighting areas absorbing greater quantities suggestive of increased metabolic activity indicating altered blood flow, injury, or disease process within bones. Whole body scanning can aid detection of rare disorders like Paget’s Disease, stress fracture, avascular necrosis, malignancy, benign bone tumor, or bone metastases.
3. Laboratory Tests: Blood tests, serological assays, urinalysis, or synovial fluid analysis enable investigators to discern underlying systemic diseases linked with secondary forms of arthritis (like RA) from primary OA. Identification of rheumatoid factor, anti-citrullinated protein antibodies (ACPA), antinuclear antibody (ANA), cyclic citrullinated peptides (CCP), HLA-B27 antigen, sedimentation rate (ESR), or C-reactive protein (CRP) provides valuable information guiding appropriate therapy initiation.

The diagnosis of “arthritis of the knee joint” is confirmed on the basis of a characteristic clinical picture of the disease and the results of instrumental and laboratory methods of investigation.

With this disease, there are no specific laboratory indicators, common signs of inflammation – leukocytosis, acceleration of ESR in the general blood test and indicators of the acute phase in the biochemical. At present, laboratory markers of arthritis are being searched for, which would allow diagnosing the disease at an early pre-clinical stage.

Radiography

The main instrumental diagnostic method for knee arthritis is radiography. The study is carried out in 3 projections: a straight standing, lateral lying with a bent joint at 20-35 °, axial (along a long axis). There are a number of specific criteria that confirm the presence of the disease:

• narrowing of the joint space;
• thinning of the cartilage;
• osteophytes (pathological bony outgrowths), “articular mice” (fragments of osteophytes);
• sclerotherapy of bone tissue of articular surfaces, bone cysts;
• flattening and deformation of joint surfaces;
• curvature of the limb axis.

In addition to radiographic examination, the following methods are also used to confirm the diagnosis:

• atraumatic arthroscopy;
• ultrasonography (assessment of the thickness of articular cartilage, synovial membrane, the size of supra- and intrapatellar bags, the presence of fluid);
• CT scan;
• magnetic resonance tomography;
• scintigraphy (assessment of the bone tissue condition of the heads of the bones that form the joint).

Pain in arthritis of the knee joint initially worries patients only during exercise (especially when walking uphill, downhill and climbing stairs, while doing sports, staying for a long time in a standing position) and quiet down at rest.

Treatment of Knee Arthritis

Treatment of the disease is carried out in several areas: pharmacological correction, physiotherapy, lifestyle modification. Operative methods of treatment are used not only when the conservative is ineffective, there are a number of manipulations that are carried out even in the early stages of the disease in order to minimize clinical manifestations.

Under the modification of the way of life is understood the change in the stereotype of physical activity, the exclusion of risk factors, the rational mode of work and rest, the reduction of body weight with the help of diet, the rejection of bad habits.

The medicamentous treatment of arthritis of the knee joint is carried out by the following preparations:

• non-steroidal anti-inflammatory drugs – are used to stop pain syndrome, to remove signs of inflammation in case of exacerbation of the disease;
• Glucocorticosteroid hormones (intra-articular injection for the treatment of synovitis phenomena) – are applied in a limited way, in cases when it is necessary to eliminate painful symptoms in the shortest possible time;
• antifermentary agents (proteolysis inhibitors) – prevent the progression of degenerative and degenerative processes in the cartilaginous and bone tissues;
• spasmolytics – allow to eliminate local muscle spasm in the damaged segment;
• anabolic drugs – accelerate the regeneration of damaged tissues;
• angioprotectors – contribute to strengthening the walls of the vessels of the microcirculatory bed, providing adequate blood supply to the damaged area;
• means that improve microcirculation;
• chondroprotectors (despite the massive spread of chondroprotectors in the therapy of arthritis, their clinical efficacy has not been proven in broad placebo-controlled studies).

Physiotherapy techniques used to treat gonarthritis are very diverse:

• massage of regional muscles, improving blood circulation and stopping local spasm;
• acupuncture;
• active kinesiotherapy with the use of simulators;
• physiotherapy;
• laser therapy;
• UHF exposure;
• ultrasound treatment;
• diadynamic therapy (exposure to DC currents of 50 and 100 Hz);
• amplipulse therapy (effect on the joint area of ​​an alternating sinusoidal current of frequency 5 kHz);
• darsonvalization (use of pulsed current of high frequency);
• interference therapy (exposure to alternating current pulses of two different frequencies);
• therapeutic baths, mud, paraffinotherapy.

If ineffectiveness of these methods of exposure, in the presence of complications, resort to the surgical treatment of arthritis of the knee joint:

• decompression of metaepiphysis and prolonged intraosseous blockades (reduction of intraosseous pressure in the affected area);
• corrective osteotomy;
• arthroplasty of joints.

In the early stages of the disease, mechanical, laser or cold-plasma debridement is used (smoothing the surface of the damaged cartilage, removing the non-viable areas). This method effectively suppresses pain syndrome, but has a temporary effect – 2-3 years.

Knee arthritis: Possible complications and consequences

Arthritis of the knee joint can have the following complications:

• stiffness or immobility of the knee;
• defeat of the hip joint both on the side of the lesion, and on the opposite (due to the redistribution of the load).

Forecast

Unlike coxarthrosis leading to disability, arthritis of the knee joint is much easier, but due to the developing synovitis, a decrease in working capacity is possible, and social activity, sometimes very significantly, also suffers.

The favorable prognosis directly depends on the timeliness of the diagnosis and the initiation of medical and physiotherapeutic treatment. The prognosis worsens while delaying the decision on the surgical treatment of the disease, if necessary.

Prevention

• Timely full-fledged treatment of acute knee joint injuries in case of their occurrence with mandatory subsequent rehabilitation.
• Treatment of the underlying disease, accompanied by a risk of developing secondary arthritis.
• Control of body weight.
• Dosed physical activity.
• Correction of existing violations of the biomechanics of the axial skeleton (flat feet, scoliosis).
• Exclusion of the impact of damaging factors (wearing shoes at excessively high heels, hypothermia of the joints, prolonged static load).
• Dynamic outpatient monitoring in a rheumatologist, orthopedist when diagnosed.