What conditions are treated with a knee prosthesis and what interventions are available? Let’s explore together.
Osteoarthritis is a chronic degenerative disease, a complex condition where the deterioration of joint cartilage occurs, leading to progressive wear until complete loss.
This results in joint stiffness, pain, inflammation and functional limitation.
Osteoarthritis of the lower limb can benefit enormously from medical therapy with an individualized rehabilitation program aimed at muscle strengthening.
In its early stage osteoarthritis can also improve with a series of non-surgical interventions such as weight loss, cartilage supplements, targeted physiotherapy and anti-inflammatory medications to manage pain. Injections of medications into the joint can also provide benefits.
As the disease progresses, it becomes impossible to engage in sports and daily activities like walking or climbing stairs are limited, with pain present even at night. In these stages prosthetic surgery is necessary to alleviate symptoms, eliminate pain and restore joint movement.
When is surgery recommended?
Surgery is recommended when an X-ray shows severe osteoarthritis with bone-on-bone contact and the following symptoms are present:
- pain resistant to painkillers;
- constant pain even at rest;
- difficulty standing for long periods;
- inability to perform daily activities;
- pain while walking;
- limited or no benefit from physiotherapy and conservative treatments.
In this article we cover:
- conditions treatable with knee prosthesis
- knee prosthesis surgery
- total and unicompartmental knee prosthesis
- latest generation minimally invasive knee prosthesis
1- Conditions treatable with knee prosthesis
Conditions necessitating knee prosthesis surgery include:
- osteoarthritis;
- osteonecrosis;
- rheumatoid arthritis;
- post-traumatic osteoarthritis.
The knee is the largest joint in the human body, composed of the femur, tibia and patella, allowing for leg flexion and extension. Muscles and ligaments hold these components together, providing stability and enabling movement. The articular surfaces of these bones are covered with cartilage, which cushions the contact between joint ends and reduces friction during movement.
Osteoarthritis of the knee
This condition is characterized by the gradual deterioration and loss of cartilage, which can be secondary to an initial trauma or a progressive wear typical with aging.
Early osteoarthritis causes pain following prolonged joint use; symptoms worsen over time, leading to stiffness and increased pain.
In advanced stages patients can walk only short distances, have significant difficulty climbing stairs and have trouble standing up from a seated position.
Osteonecrosis
In osteonecrosis blood supply to the bone is interrupted, causing sudden localized pain in a part of the knee that persists even at rest, lasting through the night.
The femoral condyles, particularly the medial one, are primarily affected.
Early diagnosis offers healing possibilities, but when bone and cartilage are destroyed, surgical therapy with small prostheses to treat the affected area is necessary.
Rheumatoid arthritis
This chronic inflammatory disease causes cartilage deterioration due to an attack by the immune system.
Post-traumatic osteoarthritis
This condition results from damage following an articular fracture or is a consequence of a fracture that doesn’t directly involve the joint but causes functional alteration.
If you want to go deeper into this matter, please have a look at this article.
2- Knee prosthesis surgery
In most cases a knee prosthesis is recommended for advanced and symptomatic osteoarthritis when conservative therapy (injections, physiotherapy, medications, etc.) is not effective.
It is also recommended when the pain is resistant to pain therapy or when continuous use of painkillers is necessary for walking and leading a normal life.
For patients with diffuse knee osteoarthritis or autoimmune diseases a total knee prosthesis is advised, while patients with osteoarthritis in only one portion of the knee can benefit from a unicompartmental prosthesis, which ensures a quicker recovery.
The total knee prosthesis consists of 4 components:
- – the femoral shield is made of metal, coated with alloys that reduce friction and wear during movement. Once positioned, it encases the articular part of the femur;
- – the tibial component is made of titanium and usually has a small stem that enters the tibia bone for a few centimeters to increase stability;
- – on the tibial component a polyethylene insert is placed, a highly resistant material that develops very little friction during the movement of the prosthesis;
- – the patellar component is a polyethylene button that is applied to the patella when this bone is also damaged by osteoarthritis or in cases where the joint is affected by a rheumatologic disease.
There are many types of knee prostheses, allowing for customization based on the patient’s needs.
The orthopedic surgeon examines the patient and reviews the knee X-rays taken while standing “under load.”
All patients with chronic knee pain caused by osteoarthritis can benefit from a knee prosthesis.
Finding a specialist in knee prosthetic surgery is the best guarantee for a good outcome.
The consultation with the orthopedic surgeon is the first step in assessing the need for a knee prosthesis.
It is important to remember that not all patients need surgery and not all knee pain can be cured by a prosthesis.
The knee replacement operation
The operation is aimed at ensuring the safety and well-being of the patient during the surgical procedure.
The intervention begins with the administration of anesthesia: the safest and most commonly used is spinal anesthesia, which can be combined with a sedative if the patient wishes to be sedated.
Spinal anesthesia is not painful and has many advantages: it reduces the risk of venous thrombosis, the risk of bleeding, and improves pain control in the immediate postoperative period.
The patient is then positioned on the operating table and the limb is disinfected.
After that, the damaged parts are replaced with prosthetic components.
The procedure ends with the suturing of the incision and its dressing.
It lasts about an hour, but from the moment the patient enters the operating room to the moment they leave the ward approximately 2-3 hours pass.
Finally the awakening phase can vary in duration.
The patient returns from the operating room without a urinary catheter and without surgical drainage.
Overall the hospital stay lasts 3-4 days.
The facility has a rehabilitation ward that can be accessed by patients undergoing joint prosthesis surgery.
If necessary the hospital stay can be extended to carry out physiotherapy; otherwise the patient can start an outpatient or home-based rehabilitation program.
Knee prosthesis is one of the most reliable medical procedures and has transformed the lives of many patients, allowing them to return to an active, pain-free life.
The prostheses last more than 20 years in 90% of patients and more than 25 years in 80% of patients.
It remains important to have an annual check-up X-ray and an orthopedic visit to verify the state of health.
If you want to learn more, read this article.
3- Total and unicompartmental knee prosthesis
Some diseases lead to the irreversible destruction of joint ends and only a prosthesis can definitively resolve such symptoms.
Different types of knee prostheses exist: total coverage prosthesis and partial or unicompartmental prosthesis.
The surgical procedure removes the damaged cartilage and bone, which is replaced with the prosthetic implant.
Prostheses are made of various materials: titanium, polyethylene, chrome, cobalt and cement often used to secure them firmly to the bone.
Typically a small amount of bone from the tibia, femur and patella is removed during the procedure to eliminate the damaged structures and create high-quality bone surfaces for the prosthetic implant.
Most ligaments and tendons are left intact, allowing for natural knee movement.
Total knee prosthesis
In total knee prosthesis, diseased bone and cartilage are removed and replaced with prosthetic components.
Each knee prosthesis procedure is customized based on the patient’s needs, with significant variations from case to case.
General steps include:
- administration of anesthesia and, in agreement with the patient, sedation;
- surgical incision in front of the knee to access the joint;
- removal of damaged cartilage and bone, preparing the bone ends for the implant;
- ensuring the prosthetic components are correctly positioned on the bone;
- testing the new joint;
- closing the incision.
Unicompartmental knee prosthesis: What does it mean?
Orthopedic surgeons specialized in prosthetic surgery have the skills to choose the type of prosthesis. The treatment path must be personalized starting from the implant choice.
The partial knee prosthesis is the smallest knee prosthesis implantable: it respects the anatomy and allows for rapid healing.
Some diseases affect only one part of the joint: conditions like bone necrosis affect a well-defined area of the bone and cartilage, making this technique possible.
When knee osteoarthritis involves only one part of the joint, it is possible to intervene with a partial prosthesis, which is smaller and preserves all healthy portions of the knee.
Unicompartmental prostheses have excellent results and long survival due to improved knowledge and advanced materials of the latest generation.
The lesser surgical trauma allows for very rapid recovery, with the patient walking with full weight on the operated limb just a few hours after the procedure and usually the hospital stay is short, about 3 days.
Partial prostheses have significant advantages over total ones:
- smaller surgical incision;
- shorter operation duration;
- less bleeding;
- less pain;
- less swelling;
- better joint stability.
The unicompartmental prosthesis covers the damaged knee portion, leaving other joint structures intact.
Materials used
In recent years prosthesis designs and available sizes have significantly increased.
The most commonly used metal is titanium, coated with a chrome-cobalt alloy that has shown excellent resistance over time.
Chrome-cobalt contains nickel, to which some patients may be allergic, but nickel-free prostheses are available for these patients.
The latest generation polyethylene, called cross-linked, is highly wear-resistant.
Typically the knee prosthesis is fixed to the bone with cement, ensuring immediate and solid anchoring with a long-lasting duration.
In some patients, such as young people with good bone quality, non-cemented prostheses made of a material integrating with the bone can be used.
For further information you can come to this page.
4- Latest generation minimally invasive knee prosthesis
When knee pain is so intense that it prevents even the simplest movements, such as walking, driving or climbing stairs, it is possible to consult an orthopedic specialist. It is crucial to understand the situation and choose the most suitable treatment solutions:
- total knee prosthesis;
- partial knee prosthesis.
In some clinics in Tuscany, specifically in Florence, Pontassieve and the Valdarno area you can quickly return to daily habits without fear and pain, thanks to the Rapid Recovery technique and minimally invasive surgery. The concept of minimally invasive knee prosthesis, besides the aesthetic advantage, mainly aims at less surgical trauma and immediate patient recovery.
The minimally invasive approach is feasible for all patients undergoing knee prosthesis, whether partial or total, resulting in a better patient experience during and after the surgical procedure.
Severe gonarthrosis unresponsive to medications can be resolved with a modern minimally invasive prosthetic surgery, replacing the cartilage and joint damaged by osteoarthritis or part of it with a latest-generation prosthesis. The choice of implant type depends on various factors: the type of osteoarthritis, the patient’s age and activity level and bone quality. Depending on the patient’s condition a total or partial knee prosthesis can be implanted.
Today’s prosthetic surgery can be performed with minimally invasive surgery, respecting the body’s noble tissues and allowing rapid recovery.
Minimally invasive total knee prosthesis
A minimally invasive total knee replacement is performed if the knee is damaged in all three of its compartments (medial femorotibial, lateral femorotibial and femoropatellar).
During the surgery an incision is made at the medial parapatellar site, avoiding the cutting of the tendon and its muscle fibers.
This type of prosthesis can be done while preserving the posterior cruciate ligament, which is responsible for proprioception and stability of the knee..
Minimally invasive unicompartmental or partial knee prosthesis
A minimally invasive prosthesis replaces only the damaged compartment of the knee, resulting in less surgical stress, less blood loss, less pain and a faster functional recovery.
Additionally the healthy part of the joint is preserved.
There are partial prostheses available for the inner compartment, the outer compartment and the patella.
Patello-femoral prosthesis
It is suitable for patients who develop selective patellar osteoarthritis and experience symptoms primarily during movements with a flexed knee, such as getting up from a chair or climbing stairs.
It is called a femoropatellar prosthesis because it replaces only the femoropatellar compartment.
Minimally invasive surgery works on the patient’s psychophysical well-being
Before the procedure the rapid recovery approach includes educating and physically preparing patients, also through the use of a dedicated application, MyMobility.
Information allows for greater patient participation and motivation, while physical preparation helps limit muscle mass loss post-surgery.
The minimally invasive knee replacement procedure involves the use of smaller, wear-resistant, technologically advanced prostheses that are so customized they are practically tailored to the patient. In the case of unicompartmental knee prosthesis implantation, healthy parts, including the anterior and posterior cruciate ligaments, which are essential for physiological joint movement, kinematics and sensitivity are preserved.
Compared to traditional surgery, minimally invasive surgery offers the following advantages:
- reduced surgery, hospitalization, rehabilitation and recovery times;
- smaller incisions, resulting in less noticeable scars;
- use of glue instead of stitches for better skin healing;
- reduced bleeding during and after the operation;
- reduced pain thanks to multimodal therapy.
The consequence of all this is a patient who feels well immediately, leading to a shorter hospital stay, less strenuous and painful rehabilitation and a very rapid recovery. The primary goal of Rapid Recovery is to get the patient up and walking within 5-6 hours after surgery, aiming for early functional recovery. Complete healing will occur in about 2-3 months.
If you want to learn more read this article.
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