Gonarthrosis of the knee joint is the most common localization of a degenerative-dystrophic disease, which is characterized by gradual destruction of cartilage with subsequent changes in the articular surfaces, which is accompanied by pain and decreased mobility.
The disease is more likely to affect women over 40, especially those with overweight and varicose veins of the lower extremities.
The knee joint is made up of three compartments:
- medial tibiofemoral;
- lateral tibiofemoral;
- suprapatellar-femoral.
These compartments can be affected by deforming osteoarthritis (DOA) both individually and in any combination. 75% of all cases of gonarthrosis are the destruction of the medial tibiofemoral compartment (during movements, it experiences a load exceeding body weight by 2–3 times).
In young patients, only one joint is more often destroyed - the right or left (right-sided or left-sided gonarthrosis).
Causes of DOA of the knee joint
Several factors may be involved in the development of degenerative cartilage changes simultaneously:
- mechanical overload of the knee joint (some specialties, sports) with microtraumatization of the cartilage;
- consequences of injuries, surgical interventions (meniscectomy);
- inflammatory diseases of the knee (arthritis);
- anatomical inconsistencies of the articular surfaces (dysplasia);
- violation of statics (flat feet, curvature of the spine);
- chronic hemarthrosis (accumulation of blood in the synovial cavity);
- metabolic pathology (gout, hemochromatosis, chondrocalcinosis);
- excess body weight;
- violations of the blood supply to the bone;
- osteodystrophy (Paget's disease);
- neurological diseases, loss of sensation in the limbs;
- endocrine disorders (acromegaly, diabetes mellitus, amenorrhea, hyperparathyroidism);
- genetic predisposition (generalized forms of osteoarthritis);
- violation of the synthesis of type II collagen.
But in 40% of cases, it is impossible to establish the root cause of the disease (primary arthrosis).
Pathogenesis of gonarthrosis
initial stage
In the initial stage of the disease, the processes of cartilage metabolism are disturbed. The synthesis and quality of the main structural unit of cartilage tissue, proteoglycans, which are responsible for the stability of the structure of the collagen network, are reduced.
As a result, chondroitin sulfate, keratin, hyaluronic acid are washed out of the mesh, and structurally defective proteoglycans can no longer retain water. It is absorbed into collagen, the swollen fibers of which lead to a decrease in the resistance of cartilage to stress.
Pro-inflammatory substances accumulate in the synovial cavity, under the influence of which the cartilage is destroyed even faster. Fibrosis of the articular capsule develops. The change in the composition of the synovial fluid makes it difficult to deliver nutrients to the cartilage and impairs the sliding of the articular surfaces during movement.
Progression of pathology
In the future, the cartilage gradually becomes thinner, becomes rough, cracks form throughout its entire thickness. The epiphyses of bones experience an increased load, which provokes the development of osteosclerosis and compensatory proliferation of bone tissues (osteophytes).
This reaction of the body is aimed at increasing the area of the articular surfaces and redistributing the load. But the presence of osteophytes increases discomfort, deformity and further limits the mobility of the limb.
Microfractures are formed in the thickness of the bone, which injure the vessels and lead to intraosseous hypertension. In the last stage of osteoarthritis, the articular surfaces are completely exposed, deformed, limb movements are sharply limited.
Symptoms of gonarthrosis of the knee joint
Arthrosis of the knee joint is characterized by a chronic, slowly progressive course (months, years). The clinic grows gradually, without pronounced exacerbations. The patient cannot remember exactly when the first symptoms appeared.
Clinical manifestations of gonarthrosis:
- pain. At first, diffuse, short (with prolonged standing, walking up the stairs), and as osteoarthritis progresses, pain becomes local (front and inner surface of the knee), their intensity increases;
- local sensitivity to palpation. Mostly on the inside of the knee along the edge of the joint space;
- crunch. In stage I it may be inaudible, in II-III it accompanies all movements;
- increase in volume, deformation of the knee. As a result of the weakening of the lateral ligaments, a person develops an O-shaped configuration of the limbs (it is clearly visible even in the photo);
- restriction of mobility. At first, there are difficulties with bending the knee, later - with extension.
Causes of pain in DOA:
- mechanical friction of damaged articular surfaces;
- increased intraosseous pressure, venous congestion;
- accession of synovitis;
- changes in periarticular tissues (stretching of the capsule, ligaments, tendons);
- thickening of the periosteum;
- phenomena of dystrophy in the adjacent muscles;
- fibromyalgia;
- compression of nerve endings.
In contrast to coxarthrosis, DOA of the knee may show spontaneous regression of symptoms.
Clinical manifestations of gonarthrosis depending on the stage:
| Characteristics | I stage | II stage | III stage |
|---|---|---|---|
| Pain | Short, occurs more often when the knee is extended (prolonged standing, walking up the stairs) | Moderate, disappears after a night's rest | Pronounced, disturbing even at night |
| Mobility restriction | Not visible | There is a restriction of extension, mild lameness | Persistent flexion-extensor contractures, lameness |
| crunching | Not | Feelable on palpation during movement | remote crunch |
| Deformation | Missing | Slight deviation of the axis of the limb anteriorly, muscle wasting | Valgus or varus deformity. The joint is unstable, atrophy of the thigh muscles |
| X-ray picture | Slight narrowing of the joint space, initial signs of subchondral osteosclerosis | The joint space is narrowed by 50% or more, osteophytes appear | Almost complete absence of the joint space, significant deformation and sclerosis of the articular surfaces, areas of subchondral bone necrosis, osteoporosis |
A frequent complication of arthrosis of the knee joint is secondary reactive synovitis, which is characterized by the following symptoms:
- growing pain;
- puffiness;
- effusion into the synovial cavity;
- increase in skin temperature.
Less frequent and more dangerous complications include: blockade of the joint, osteonecrosis of the femoral condyle, subluxation of the patella, spontaneous hemarthrosis.
Diagnosis of DOA of the knee joint
Diagnosis of gonarthrosis is based on the patient's characteristic complaints, changes detected during examination and the results of additional tests.
To confirm osteoarthritis, it is prescribed:
- radiography of the knee joint in two projections (anteroposterior and lateral): the most accessible way to confirm the diagnosis in the advanced stage of pathology;
- Ultrasound: determination of the presence of effusion in the joint, measurement of cartilage thickness;
- analysis of synovial fluid;
- diagnostic arthroscopy (visual assessment of cartilage) with biopsy;
- computed and magnetic resonance imaging (CT, MRI): the best method for diagnosing DOA in the early stages.
If the doctor has doubts about the diagnosis, it may be prescribed:
- scintigraphy: scanning of the joint after the introduction of a radioactive isotope;
- thermography: study of the intensity of infrared radiation (its strength is directly proportional to the strength of inflammation).
Treatment of gonarthrosis of the knee joint
The treatment regimen for osteoarthritis combines several approaches: non-drug methods, pharmacotherapy and surgical correction. The ratio of each method is determined individually for each patient.
Non-drug treatment
In the latest ESCEO (European Society for the Clinical Aspects of Osteoporosis and Osteoarthritis) guidelines on how to treat osteoarthritis of the knee, experts place particular emphasis on patient education and lifestyle modification.
The patient needs:
- explain what the essence of the disease is, set up for long-term treatment;
- teach how to use assistive devices (canes, orthoses);
- prescribe a diet (for patients with a body mass index of more than 30);
- give a set of exercises to strengthen the thigh muscles and unload the knee joint;
- explain the importance of increased physical activity.
In the early stages of knee arthrosis, physiotherapy methods of treatment give good results:
- massage;
- magnetotherapy;
- UHF therapy;
- electrophoresis;
- hydrogen sulfide baths;
- paraffin applications;
- acupuncture.
Pharmacotherapy of gonarthrosis
The use of drugs in DOA is aimed at relieving pain, reducing inflammation, and slowing down the rate of cartilage destruction.
Symptomatic treatment:
- analgesics;
- non-steroidal anti-inflammatory substances (NSAIDs) of the group of COX-2 inhibitors in the form of tablets or suppositories;
- non-narcotic analgesics (with resistant pain syndrome).
Structure-modifying drugs (chondroprotectors):
- Chondroitin sulfate;
- Glucosamine sulfate.
These drugs can be taken in the form of capsules in courses several times a year, injected intramuscularly or directly into the synovial cavity.
Local therapy includes near- and intra-articular injections of glucocorticosteroids, hyaluronic acid preparations.
At stages I–II of DOA, an important place in complex therapy is the use of anti-inflammatory ointments, gels and creams based on NSAIDs. They help reduce the patient's need to take NSAIDs orally, thereby reducing the risk of damage to the digestive tract.
Folk remedies
The use of tinctures, decoctions, extracts, local applications of medicinal plants should be considered as auxiliary methods for the treatment of DOA, folk remedies cannot replace the therapy prescribed by the doctor.
Plants used in osteoarthritis: dandelion, ginger, Jerusalem artichoke, burdock, garlic, sea buckthorn.
Surgery
Surgical intervention may be required at all stages of gonarthrosis with insufficient effect of medical measures. The most common are endoscopic procedures, in the most severe cases endoprosthesis replacement is indicated.
Types of endoscopic interventions:
- revision and rehabilitation of the joint: extraction of inflammatory contents from the synovial cavity, fragments of cartilage;
- plasma or laser ablation: removal of mechanical obstructions in the synovial cavity;
- chondroplasty.
Corrective periarticular osteotomy is indicated for patients with initial manifestations of axial limb deformity (no more than 15–20%).
The purpose of the operation is to restore the normal configuration of the joint, evenly distribute the load over the articular surface, and remove damaged areas. This procedure allows you to delay arthroplasty.
Indications for replacing the affected area (or the entire joint) with an artificial one:
- DOA II-III degree;
- severe axial deformity of the limb;
- aseptic necrosis of the subchondral layer of the bone;
- persistent pain syndrome.
Contraindications for knee arthroplasty:
- total damage to the joint;
- unstable ligamentous apparatus;
- DOA as a consequence of inflammatory arthritis;
- persistent flexion contracture, severe muscle weakness.
In this case, the patient undergoes arthrodesis - a comparison of the knee joint in a physiological position with the removal of the articular surfaces. This eliminates pain but shortens the leg, causing secondary lesions in the contralateral knee, hip, and spine.
Prevention
Prevention of premature cartilage degeneration should begin in childhood.
Precautionary measures:
- scoliosis prevention;
- correction of flat feet (shoes with arch supports);
- regular physical education (limit heavy sports);
- exclusion of fixed postures during work.