If, for any reason, the articular cartilage is damaged, a condition appears, which is called osteoarthritis.
The friction between the bones, that are no longer protected by the cartilage, produces the osteoarthritis symptoms: pain, swelling, stiffness, movement restriction.
Osteoarthritis is the most common type of arthritis, as a rule affecting people over the age of 45.
The friction between the bones is minimized by synovial fluid and cartilage, covering the contacting areas. Between femur and tibia there are two more, wedge-shaped, cartilaginous structures – the menisci, whose function it is to absorb vibrations and stabilize the joint. The bones are connected to each other with ligaments, mainly the two cruciates – anterior and posterior- and the two collaterals – medial and lateral.
These ligaments are also important for the stability of the joint. Tendons attach muscles to the bones, making movement possible.
– Weight
– Heredity
– Sex – women over the age of 55 are affected more often than men
– Repeated injuries associated with loading of the joint, due to sporting activities or work-related
– Coexistence with other types of arthritis, such as rheumatoid arthritis, or certain metabolic disorders.
Diagnosis is made by clinical examination and X-rays, while in some cases magnetic resonance imaging (MRI) may be additionally indicated.
The initial therapeutic approach is conservative: weight loss recommendation, strength training, analgesics, anti-inflammatory drugs, corticosteroid injections, physiotherapy, and alternative therapies such as acupuncture.
However, in advanced situations, when there is considerable pain, the best solution is surgical treatment. In this way deformity is corrected, function is restored and pain is relieved.
The surgical techniques that can be used are mainly three:
– Total knee arthroplasty
– Unicompartmental knee arthroplasty
– Osteotomies
This is a surgical procedure by which the entire joint – the lower end of the femur, the upper end of the tibia and the meniscus between them – is replaced by metal and plastic implants. Its application started more than fifty years ago, with constant development and improvement of materials and surgical techniques.
MINIMALLY INVASIVE TOTAL KNEE ARTHROPLASTY – MIS
Minimize the injury to the soft parts of the joint upon insertion of the artificial prosthesis. This is achieved by the use of special instruments that allow manipulations through a small skin incision.
The most important benefit is that the quadriceps tendon is not cut through, as is done when the classic technique is used. Instead, it is raised with the aid of appropriate instruments. The integrity of this tendon is a prerequisite for rapid recovery after surgery, as the quadriceps is the largest muscle of the lower limb and responsible for the extension of the knee, but also very important for movements such as walking, running, jumping and squatting.
The operation is performed under either general or spinal anaesthesia (the latter affects the lower half of the body) and has a duration of about 90 minutes. At the end of the procedure, while the patient is still under the influence of anaesthesia, the nerves that innervate the knee are blocked with the use of a long acting local anaesthetic. This ensures analgesia without side effects for the first 24 hours. From the next day the pain is mild, due to the surgical technique, and can be effectively treated with simple analgesics.
Summing up, the benefits of soft tissue protection are:
– minimal blood loss – 95% of the patients do not need transfusion
– postoperative pain is significantly reduced compared to conventional techniques
– greater range of postoperative movement
– immediate mobilization. The patient can stand up on the first postoperative day, and on the fourth day he is ready to be released from hospital
– The length of time that the patient needs to have physiotherapy at home is limited by half, so that about a month later, the patient is ready to return to normal everyday activities such as walking or driving, and to work.
The knee joint is divided into three compartments. The medial, external and patellofemoral compartments. Often knee arthritis does not develop simultaneously in all parts of the joint, but appears in one compartment, due to local damage to the bone and cartilage.
For example, in patients with kneecaps (shape O) the outer compartment (compartment) often degenerates. In patients with weak knees (X) the medial part. In this case, as in the case of aseptic necrosis of one of the two femoral condyles, only one – the worn – part of the joint can be replaced, with the operation called unicompartmental knee arthroplasty.
Of course, some conditions must be met, which will be mentioned below. During this operation, the worn surface is replaced with metal and plastic implants, while the healthy part of the joint (cartilage, ligaments, bone) is kept intact, ensuring some important advantages:
– Minimally invasive
– Small incision
– Zero blood loss
– Minimal postoperative pain
– Faster recovery
– Instant charging
– Better movement after surgery
Conditions for the one-room apartment to have an indication are:
– the arthritis concerns only one part of the joint
– the links are functional
– not having had a previous meniscectomy in the other compartment
– that there is no significant stiffness of the knee
– no inflammatory joint disease, such as rheumatoid arthritis
The pre-operative check-up includes simple X-rays and MRI of the joint, the surgery takes about 1 – 1.5 hours and the hospital stay lasts 2 – 3 days.
The lifespan of one-bedroom apartments, as seen so far, is 10-15 years. For this reason, its use is avoided in young patients, in whom the application of osteotomy is preferred. Nevertheless, age is not a prohibitive contraindication, as it allows delaying a total knee arthroplasty with excellent quality of life in between.
Corrective knee osteotomies are another alternative for treatment of initial stage osteoarthritis, affecting a single joint compartment (inner or outer).
They are applied in young, active patients (usually less than 50 years of age), in whom total knee arthroplasty is expected to have a shorter life span compared to older people, due to greater strain of the joint. After a detailed pre-operative check (including simple x-rays and / or axis measurement of the lower limbs with a CT scan), the placement of osteotomy and its type will be decided.
In general, in cases of osteoarthritis of the inner compartment (valus knee) the osteotomy is placed in the tibia (either on the outer surface with removal of a wedge of bone, or on the inner surface with bone dilation), while in osteoarthritis of the outer compartment (valgus knee) the osteotomy is placed on the femur (either on the outer surface with dilation of the bone or on the inner surface with removal of a wedge). Once the desired bone axis correction has been achieved, it is stabilized with a special metal plate.
Correction of the axis results in a better distribution of loads between the joint compartments. Thus, the progression of osteoarthritis is slowed down and total arthroplasty only becomes necessary after many years, while a good bone substrate has been maintained.