Knees, just like hips, are the joints most at risk of arthrosis, a degenerative disease of the bone, caused by the progressive wear of cartilage protecting the ends of bones in a joint. Osteoarthrosis (not to be confused with osteoarthritis!) is the most common joint disorder in the past 50 years, above all among women, and to date there is still unfortunately no definitive cure, with the exception of a prosthetic replacement in a number of cases.
However, in the specific case of knee arthrosis, physiotherapy and physical activity can help, not only to improve mobility and joint flexibility, but also to slow down the course of the condition, significantly improving the quality of life.
Knee arthrosis: What is it, how it progresses, population age and range affected
Osteoarthrosis of the knee, known in the medical field also as gonarthrosis, is a degenerative disease of the knee joint, caused by excessive wear of the joint cartilage, in other words the tissue covering the ends of the bones in the joint, protecting them from friction during movement. Cartilage acts in a very similar way to a shock absorber, enabling the ends of the joints to move smoothly without causing damage to the bones. In the case of arthrosis, the cartilage wears down progressively to the point where friction between the bones reaches such a high level that joint functionality is impaired, causing joint pain and stiffness.
Knee arthrosis, in 35% of cases affects the patellofemoral joint and in 45-50% of cases the femorotibial joint. Often at this point, due to an altered distribution of load between the inner and outer compartment of the knee, there is premature wear of the medial (inside) compartment (the most frequent) or the lateral (outside) compartment.
Knee arthrosis is an irreversible and progressive condition, which mainly affects the elderly. An advanced age is therefore the main cause, but is not the only one, because other factors can contribute to this condition such as being overweight/obese, sustaining a serious injury to the knee, or simply genetic predisposition.
Symptoms: From the pre-arthrosis stage to fully developed gonarthrosis
In clinical terms, we can describe as “pre-arthrosis stage” the phase of early onset, including muscular hypotonia, ligament laxity, tendon alterations, and intermittent knee pain. This condition usually progresses to become fully developed arthrosis in 10 – 15 years.
In the phase of advanced gonarthrosis, the patient will complain of pain at rest, which increases when under load, going downstairs, and walking on uneven surfaces. The joint pain, often also overnight, is often located below the patella, on the inside of the knee, in the popliteal fossa (knee pit), then spreading to the entire joint.
Patients find it difficult to walk after sitting for long periods, and the joint is often stiff and swollen.
How to tell if it is gonarthrosis: diagnosis
Gonarthrosis is diagnosed by the doctor based on the patient’s clinical history, a physical examination and by x-rays. The images highlight the narrowing of the joint line, erosion of the radiographic contours and other typical symptoms, such as osteophytes (small bone spurs that form on the joint, typical of degenerative phenomena like arthrosis), osteosclerosis (i.e. thickening of the bone, which becomes harder and more compact, losing elasticity) and the presence of subchondral geodes (bone cysts).
Knee arthrosis: how to treat it?
Is there a specific treatment? Does physiotherapy help?
Unfortunately, there is still no cure for arthrosis. In fact, treatments are aimed at controlling symptoms and, where possible, delaying progression.
Once the orthopaedic specialist has gathered all useful information and has diagnosed the degree of arthrosis (Grade 1, 2, 3, or 4), the first step to take is to make a rehabilitation plan together with the physiotherapist. The physiotherapy plan for knee arthrosis should have the following objectives:
- Joint pain management;
- Recovery of knee joint functionality;
- Strengthening of the leg muscle component;
- Recovery of proprioceptive sensitivity;
- Improving quality of life in general.
Consequently, the rehabilitation-physiotherapy plan, in the case of knee arthrosis -but also for osteoarthrosis in general- needs to maintain a global approach, including on the one hand a specific treatment for the pain, and on the other the importance of therapeutic exercises and physical activity:
- Joint pain treatment: It is essential to understand which activities should be avoided, how to balance rest phases and how to use knee braces if needed. In the case of gonarthrosis, additional physical therapies such as Tecar, ultrasound, laser and magnetotherapy can be of valid support to pain relief.
- Therapeutic exercise and physical activity: These are two key elements in the treatment of osteoarthrosis. Exercises and gymnastics bring enormous benefits, including an increase in muscle strength and resistance, weight loss, improvement in proprioception of the joint and reduction in negative psychological factors such as anxiety and depression.
Knee arthrosis and diet: How much does body weight influence progression of the disease?
Being overweight or obese are two of the main risk factors for the progression of knee arthrosis: Excessive load on the joint can in fact lead to premature wear of the cartilage. Therefore, if the individual case requires it, targeted weight loss makes sense, both as a preventive measure and during advanced arthrosis in order to reduce joint stress.
Knee replacement: Is surgery the final solution? What are the recovery times? Is it possible to regain 100% mobility and functionality?
When dealing with gonarthrosis, surgical intervention is possible in the relatively early stages to slow down the arthrosis process (for example with joint cleaning), and in late stages, when there is no longer any response to conservative treatment, leading to significant disability. In this case the Orthopaedic specialist can opt for knee replacement surgery.
Post-surgery rehabilitation is essential for a successful outcome of surgery, and must be planned together with the surgeon on the basis of the prosthetic implant, the surgical technique used and the presence of any scarring.
In general, the aims of physiotherapy following knee replacement need to focus on:
- Prevention of damage due to bed confinement (e.g., Deep vein thrombosis, bed sores, etc.);
- Reaching an adequate joint ROM (range of motion, i.e., Joint flexibility expressed in degrees);
- Progressively strengthening the muscles of the knee, hip and abdominal/lumbar region;
- Gradually reaching independent mobility;
- Improving the patient’s independence in daily tasks and activities.
Generally speaking, with a good post-surgery rehabilitation plan, recovery times are at least 3 months, but physiotherapy is always recommended for 6-9 months. If the operation and post-surgery progress with the physiotherapist are successful and, in the absence of other pathologies, surgery is normally the definitive solution, with the patient returning to walking without pain and with a good range of joint motion.
Gymnastics, exercise bike, swimming pool, walking: Does sport help or worsen the disease?
As mentioned above, in the case of knee arthrosis, physical activity is one of the few solutions that offer tangible benefits to the patient. Obviously, it needs to be adapted to the physical condition of the individual and how far the arthrosis has progressed. In some cases, water-based full offloading activities take priority, such as swimming or hydrokinesitherapy, o in partial offloading activities such as cycling/exercise bike. On the other hand, in other cases activities under full load are possible, such as the gym.
How to slow down gonarthrosis: the Physiotherapist’s advice
As explained above, arthrosis is a degenerative disease for which there is no known cure, and is often influenced by genetic causes or injury; therefore, it is impossible to give standard advice to prevent or delay arthrosis, as the advice varies from case to case.
As a general rule, the recommendation is to avoid staying sedentary, ensuring from a young age to keep up regular and varied physical activity that involves the whole body. Keeping muscles toned and flexible and joints mobile is key. In the same way, it is recommended to avoid excessively traumatic, stressful or repetitive sports that can lead to premature wear of the joint.
Diet is also an important factor. Keeping fit with the ideal weight reduces the load on joints of the lower limbs, slowing down the onset of knee arthrosis. A varied and balanced diet also ensures we have the right nutrients needed to keep us healthy.
Meanwhile, in the case of trauma or significant alterations to posture (for example, one leg shorter than the other) which can lead to arthrosis, it is useful to seek the assistance of a physiotherapist or posturologist to draw up a personalised therapy to slow down the disease.