Symptoms, types, characteristics and benefits of knee replacement surgery.
Knee replacement surgery can heal chronic degenerative cartilage diseases like osteoarthritis and can also be the definitive treatment for acute conditions such as bone necrosis.
In total knee replacement (also called arthroplasty) the damaged cartilage and bone are removed and replaced with a prosthesis.
The total knee prosthesis consists of a shield that covers the femur and a titanium plate that covers the tibia.
A high-resistance plastic insert is placed between the tibial and femoral components to recreate an adequate moving surface; this material combination has shown excellent results with minimal wear over time despite use.
In selected patients a partial prosthesis (called unicompartmental prosthesis) can be used.
The unicompartmental knee prosthesis is the smallest knee prosthesis implantable: it is a minimally invasive device that respects the anatomy and allows rapid healing.
In this article, we will discuss:
- Symptoms and types of interventions: conservative treatment and surgery
- Prosthesis: all medical characteristics
- Knee replacement: who is the surgery for?
- How the surgery is performed and how long it lasts
- Benefits of knee replacement surgery
Symptoms and types of interventions: conservative treatment and surgery
In most cases knee replacement is recommended for advanced symptomatic osteoarthritis, when conservative therapy (injections, physiotherapy, medications, etc.) is ineffective.
Knee osteoarthritis is a chronic degenerative disease characterized by the progressive destruction of the articular cartilage, leading to joint deformity (the leg can become ‘bow-legged’ or ‘knock-kneed’), inflammation and pain.
In knee osteoarthritis (gonarthrosis) the pain can be widespread throughout the knee or localized to the inner part (medial osteoarthritis), the outer part (lateral osteoarthritis) or the front.
In the initial stage it can improve with weight loss and rehabilitation aimed at muscle strengthening and stretching; cartilage supplements can be used, pain managed with ice and anti-inflammatories and joint injections performed.
As the disease progresses, it becomes impossible to engage in sports and daily activities like walking or climbing stairs are limited.
Some patients may experience nocturnal pain with difficulty resting or significant difficulty rising from a seated position, in addition to a stiff or locked joint that compromises daily activities.
In advanced stages, unfortunately, conservative treatments are ineffective and prosthetic surgery is necessary to resolve the symptoms, significantly reduce or eliminate pain and restore joint movement.
Generally the surgery is recommended when the pain is resistant to pain therapy or when it is necessary to take painkillers daily to walk and lead a normal life.
For patients, who have developed widespread knee osteoarthritis or are affected by autoimmune diseases like rheumatoid arthritis, total prosthesis is recommended. Patients with osteoarthritis in only one part of the knee can benefit from a smaller unicompartmental prosthesis that guarantees faster recovery.
Prosthesis: all medical characteristics
The total knee prosthesis consists of four components:
- the femoral shield, that is made of metal, usually titanium, coated with alloys that reduce friction and wear during movement, with chromium-cobalt being one of the most common. Once positioned, it envelops the articular part of the femur;
- the tibial component is made of titanium and typically has a small stem that enters a few centimeters into the tibia bone to increase stability;
- a polyethylene insert is placed on the tibial component, a high-resistance plastic material that develops very little friction during prosthesis movement;
- the patellar component is a polyethylene button applied to the patella when this bone is also damaged by osteoarthritis or in cases where the joint is affected by a rheumatologic disease.
Knee prostheses can be either total or partial (also called unicompartmental).
In the first case (total prosthesis) the entire knee surface is covered by the prosthesis; in the second case (partial prosthesis) only the damaged part of the knee is covered by the prosthesis, while the remaining part is not modified by the surgery.
There are many types of knee prostheses allowing customization to the patient’s needs.
Orthopedic surgeons specialized in knee prosthetic surgery have the skills to choose the type of prosthesis.
There is no one-size-fits-all prosthesis; the treatment path must be personalized, starting with the choice of the implant.
Knee replacement: who is the surgery for?
To identify candidates for prosthesis surgery the orthopedic surgeon must examine the patient and review the standing knee X-rays (called “weight-bearing” X-rays).
The surgery is recommended when the X-ray shows severe osteoarthritis with bone-on-bone contact (absence of cartilage) and the presence of any of the following symptoms:
- pain resistant to pain therapies;
- constant pain even at rest;
- difficulty standing for long periods;
- inability to perform daily activities like walking or climbing stairs;
- pain while walking;
- significant difficulty rising from a seated position;
- difficulty sleeping at night due to pain;
- limited joint mobility that compromises daily activities;
- no benefit or limited benefit from physiotherapy and conservative treatments.
All patients with chronic knee pain caused by knee osteoarthritis can benefit from knee prosthesis surgery.
Especially after the failure of conservative therapies (physiotherapy, anti-inflammatories, exercise and weight loss) patients can choose to consult an orthopedic surgeon specializing in knee prosthetic surgery, who will evaluate the X-rays and examine the joint.
The outpatient visit with the orthopedic surgeon is the first step in assessing the need for knee prosthesis surgery; it is important to note that not all patients need surgery and not all knee pains can be cured with a prosthesis.
Identifying a specialist in knee prosthetic surgery is the best guarantee of a good outcome.
Conservative therapies (physiotherapy, injections) help to improve symptoms, but the only way to definitively cure osteoarthritis is to undergo total or partial knee prosthesis surgery.
The first necessary step is to undergo a consultation with an orthopedic specialist in knee prostheses. Read the article for all the information.
How the surgery is performed and how long it lasts
The effort is directed to ensure the patient’s safety and comfort during the surgical procedure.
The surgery begins with the administration of anesthesia.
The safest and most commonly used anesthesia is spinal anesthesia, a single injection into the lower part of the spine with a very thin needle; it can be combined with a sedative if the patient wants to sleep.
Spinal anesthesia is not painful, reduces the risk of venous thrombosis, can reduce the risk of bleeding and improves immediate postoperative pain control.
After the anesthesia the patient is positioned on the operating table, the limb is disinfected and sterile drapes are placed to delineate the surgical area.
Then the damaged parts are replaced with prosthetic components.
The surgery ends with the suturing of the incision and its dressing.
The surgery lasts about 1 hour.
Patients often feel that the duration is longer, because before the procedure the operating room nurses and the anesthetist follow important recognition and safety procedures, as well as administering medications for pain control.
Finally the awakening phase can vary in duration.
From the moment the patient leaves the ward to when they return, about 2-3 hours pass.
The patient returns from the operating room without a urinary catheter and without a surgical drain and once the anesthesia wears off, they can get up and walk with the physiotherapists.
The next day they will walk for a medium distance and the day after they will climb stairs.
Overall the hospital stay lasts 3-4 days.
The facility has a rehabilitation department accessible to patients who have undergone joint prosthesis surgery.
If needed, the stay can be extended for physiotherapy or outpatient or home physiotherapy can be started.
Benefits of knee replacement surgery
Knee replacement surgery cures knee osteoarthritis, eliminates pain and stiffness and is a highly successful procedure performed on many patients worldwide.
It is now one of the most reliable and predictable medical procedures and has transformed the lives of many patients, allowing them to return to an active, pain-free life.
Complications are few and infrequent, but must be mentioned for complete information and will be detailed during the preoperative visit and lesson; it is important to note that no surgical procedure in medicine is without risks.
Modern materials and advanced prosthesis designs allow for a long lifespan of the implant.
Scientific literature explains that prostheses last more than 20 years in over 90% of patients and more than 25 years in over 80% of patients.
It is important to have a regular annual X-ray and orthopedic visit to check the health status.
If you are looking for a professional, you can schedule an initial consultation with Dr. Vanni Strigelli by filling out the form.
