Knee osteoarthritis

What is knee osteoarthritis?

Knee osteoarthritis, also known as gonarthrosis, is a chronic degenerative disease that affects the knee joints.
It is characterized by the progressive breakdown of articular cartilage, the smooth, protective tissue that covers the ends of bones in a joint.

Anatomy of the Knee Joint

Constituent bones

Mechanisms
Symptoms
Factors

What are the mechanisms of knee osteoarthritis?

Cartilage Degradation
The cartilage in the knee begins to wear down and disintegrate. Without this protective cushion, the bones begin to rub directly against each other.

Inflammation
This friction leads to inflammation, pain and stiffness. Inflammation can also cause thickening of the synovial membrane and the formation of osteophytes (bony growths).

Bone Modification
Over time, bones can become denser and deformed, making symptoms worse.

What are the symptoms of knee osteoarthritis?

Symptoms of knee osteoarthritis can vary in intensity and include:

Pain
Often felt during or after physical activity.

Stiffness
Particularly marked in the morning or after a period of rest.

Swelling
Due to fluid buildup in the joint.

Reduction in Range of Motion
Difficulty fully bending or extending the knee.

Cracking or Rubbing Sensation
During knee movement, due to loss of cartilage.

What are the causes and risk factors for knee osteoarthritis?

Age
Aging: Aging is the main risk factor for knee osteoarthritis. As we age, cartilage wears down and loses its ability to repair itself.

Overweight and Obesity
Excess weight: High body weight increases the pressure on the knee joints, which accelerates the wear and tear of cartilage.

Professional and Sports Activities
Occupation: Jobs requiring repetitive movements, lifting heavy loads or prolonged standing can increase the risk of osteoarthritis.

Sports: High-impact sports or those involving frequent pivoting movements (such as football, basketball) increase the risk of knee injuries, which can lead to osteoarthritis.

Joint Trauma
Injuries: Past injuries, such as fractures, torn ligaments, or meniscus tears, can damage cartilage and lead to osteoarthritis.

Repetitive Strain Injuries: Repetitive activities or repetitive movements can cause cumulative strain injuries over time.

Inflammations and Joint Diseases
Inflammatory Arthritis: Diseases such as rheumatoid arthritis can lead to destruction of cartilage and promote osteoarthritis.
Joint Infections: Previous infections can damage cartilage and joint structures.

Metabolic and Systemic Factors
Metabolic Diseases: Certain diseases such as diabetes or hemochromatosis can affect joint health.

Bone Growth Disorders: Conditions such as bone dysplasia can alter the normal structure of the joint.

Genetic Predisposition
Heredity: A genetic predisposition can increase the risk of developing osteoarthritis. Family history plays an important role.

Sex
Gender: Women, especially after menopause, are more likely to develop knee osteoarthritis than men. Hormones may play a role in this difference.

Nutritional Factors and Lifestyle
Diet: An unbalanced diet or one deficient in certain nutrients can affect joint health.

Physical Activity: Lack of exercise can lead to muscle weakness and poor fitness, increasing the risk of developing osteoarthritis.

Biomechanical Factors
Joint Alignment: Alignment abnormalities, such as varum (bow legs) or valgum (knee-legs), can increase pressure on certain parts of the knee.

Muscle Weakness: Weak muscles around the knee can lead to joint instability and increase stress on the cartilage.

Prevention
Diagnosis
Treatments

Prevention of knee osteoarthritis

Although some causes of knee osteoarthritis cannot be avoided, such as age and genetics, several preventative measures can be taken to reduce the risk:

– Maintain a healthy weight to reduce the load on the knees.
– Regular exercise to strengthen the muscles around the joint and improve stability.
– Avoid joint trauma by using appropriate techniques during sports and professional activities.
– Take care of knee injuries as soon as they occur to minimize long-term damage.
– Balanced diet rich in essential nutrients for joint health.

By understanding these causes and risk factors, steps can be taken to protect knee joints and slow the progression of osteoarthritis.

Diagnosis of knee osteoarthritis

The diagnosis of knee osteoarthritis is based on several elements:

– Clinical Examination: Assessment of symptoms, mobility and
pain.
– Imaging: X-rays to visualize cartilage loss, osteophytes, and bone alignment. MRIs may be needed for more precise details.
– Laboratory tests: Although non-specific, they can help rule out other causes of joint pain.

What are the treatment options for knee osteoarthritis?

Treatment for knee osteoarthritis aims to relieve symptoms and improve joint function. It may include:

– Medical treatment: Nonsteroidal anti-inflammatory drugs (NSAIDs), analgesics, injections of corticosteroids, platelet-rich plasma or hyaluronic acid.
– Physiotherapy: Exercises to strengthen the muscles around the knee and improve mobility.
– Lifestyle modifications: Weight loss, low-impact activities, use of supports (cane, knee pads).
– Surgery: In advanced cases, procedures such as arthroscopy, osteotomy, or total knee replacement (prosthesis).

Knee osteoarthritis is a complex condition requiring management tailored to each patient.
Effective management relies on a multidisciplinary approach combining medical treatments, physiotherapy and, if necessary, surgical interventions.

Total knee replacement (TKR)

Total knee replacement surgery, also called total knee arthroplasty, is a surgical procedure to replace damaged or worn parts of the knee joint with artificial components.
This procedure is typically performed to relieve pain and restore knee function in patients with severe osteoarthritis, rheumatoid arthritis, or other degenerative knee conditions.

Indications
Preparation
Procedure
Rehabilitation
Complications
Results

Indications for total knee replacement

 

Severe osteoarthritis
Advanced degradation of articular cartilage causing pain and functional disability.

Rheumatoid arthritis
Chronic inflammatory disease affecting the joints.

Post-traumatic arthritis
Degeneration of the joint following injury.

Joint deformities
Genu varum (bow legs) or genu valgum (knocked legs) causing pain and poor joint function.

Pain refractory to conservative treatments
When medications, physical therapy and other non-surgical treatments no longer effectively relieve pain.

Preparation for intervention

Medical assessment:

Clinical examination
Assessment of general health and knee function.

Imaging
X-rays, MRI or CT scan to assess the extent of joint damage.

Preoperative consultations
Meetings with the anesthesiologist and other specialists to plan anesthesia and management of comorbidities.

Physical preparation
Preoperative rehabilitation: Exercises to strengthen the muscles around the knee and improve mobility.
Stopping certain medications: Medication adjustments, particularly anticoagulants.

Surgical procedure

Possible anesthesias:

– General anesthesia: The patient is completely asleep.
– Spinal/epidural anesthesia: The patient is awake but the lower body region is numb.
Incision:
– An incision is made on the front of the knee to access the joint.

Preparation of bone surfaces:
– Removal of damaged cartilage: The damaged articular surfaces of the femur, tibia and sometimes the patella are removed.
– Bone modeling: The bone ends are prepared to receive the prosthetic implants.

Placement of prosthetic components:
– Femoral component: A piece of the prosthesis is attached to the end of the femur.
– Tibial component: A piece of the prosthesis with a plastic tray is fixed to the top of the tibia.
– Patellar component (if necessary): A piece of the prosthesis is fixed to the posterior surface of the patella.

Alignment and fixing:
– The components are aligned correctly to ensure a stable and functional joint. They are fixed to the bone using surgical cement or by an adjustment
press-fit.

Closure:
– The incision is closed with sutures or staples.
– A drain may be placed to prevent fluid buildup in the joint.

Rehabilitation and Recovery

 

Hospitalization
The average length of stay is a few days. Immediate postoperative care includes pain management and prevention of complications (infections, thromboembolism).

Physiotherapy
Immediate start of rehabilitation to restore knee mobility and strength.
Specific exercises are prescribed to improve flexion, extension and stability of the joint.

Medical monitoring
Regular consultations with the surgeon to monitor healing, prosthesis adjustment and rehabilitation progress.

Potential Complications

Infections
Risk of infection of the joint or incision.

Deep vein thrombosis
Blood clots forming in the legs.

Stiffness
Loss of joint mobility.

Loosening or wear of the prosthesis
The prosthesis may become loose or worn over time, sometimes requiring surgical revision.

Expected Results

 

Pain relief
The majority of patients experience a significant reduction in pain after recovery.

Improved function
Recovery of mobility and ability to perform daily activities.

Sustainability
Modern prosthetics can last 15 to 20 years or more, depending on use and post-operative care.

Total knee replacement surgery is a major procedure that offers significant pain relief and improved quality of life for patients with severe joint disease. The success of the operation depends on adequate preparation, precise surgical technique, and rigorous rehabilitation.

Unicompartmental knee replacement

Unicompartmental knee replacement
Unicompartmental knee replacement, also called partial knee arthroplasty, is a surgical procedure to replace only the damaged part of the knee joint, rather than the entire joint.
This procedure is generally indicated for patients with osteoarthritis limited to a single compartment of the knee (internal, external or anterior).

Indications
Preparation
Procedure
Benefits
Complications
Results

Potential Complications
– Infections: Risk of infection of the joint or incision.
– Deep vein thrombosis: Formation of blood clots in the legs.
– Stiffness: Loss of joint mobility.
– Loosening or wear of the prosthesis: The prosthesis may become loose or wear over time, sometimes requiring surgical revision.

Preparation for Intervention

Medical assessment
– Clinical examination: Assessment of general health and knee function.
– Imaging: X-rays, MRI or CT scan to assess the extent of joint damage and confirm that osteoarthritis is limited to a single compartment.

Physical preparation
– Preoperative rehabilitation: Exercises to strengthen the muscles around the knee and improve mobility.
– Stopping certain medications: Medication adjustments, particularly anticoagulants.

Surgical Procedure

Possible anesthesias
– General anesthesia: The patient is completely asleep.
– Spinal/epidural anesthesia: The patient is awake but the lower body region is numb.
Incision:
– An incision is made in the front or slightly to the side of the knee to access the damaged compartment.

Preparation of bone surfaces
– Removal of damaged cartilage: The damaged articular surfaces of the targeted compartment (medial, lateral or patellofemoral) are removed.
– Bone modeling: The bone ends are prepared to receive the prosthetic implants.

Placement of prosthetic components
– Femoral component: A piece of the prosthesis is attached to the end of the femur in the affected compartment.
– Tibia component: A piece of the prosthesis with a plastic tray is attached to the top of the tibia in the affected compartment.

Alignment and fixing
– The components are aligned correctly to ensure a stable and functional joint. They are fixed to the bone using surgical cement or by an adjustment
press-fit.

Closing
– The incision is closed with sutures or staples.
– A drain may be placed to prevent fluid buildup in the joint.
Rehabilitation and Recovery

Hospitalization
– The average length of stay is generally shorter than for a total knee replacement, often one to three days. Immediate postoperative care includes pain management and prevention of complications (infections, thromboembolism).

Physiotherapy
– Immediate start of rehabilitation to restore knee mobility and strength. Specific exercises are prescribed to improve flexion, extension and stability of the joint.

Medical monitoring
– Regular consultations with the surgeon to monitor healing, prosthesis adjustment and rehabilitation progress.

Advantages of Unicompartmental Prosthesis

Bone preservation
Less bone tissue is removed compared to a total prosthesis.

Faster recovery
Less invasive, recovery can be faster.

Better knee function
Often better function and more natural feeling of the knee post-operatively.

Less post-operative pain
Due to the smaller scale of the surgery.

Potential Complications
Infections
Risk of infection of the joint or incision.

Deep vein thrombosis
Blood clots forming in the legs.

Stiffness
Loss of joint mobility.

Loosening or wear of the prosthesis
The prosthesis may become loose or worn over time, sometimes requiring surgical revision.

Expected Results

Pain relief
The majority of patients experience a significant reduction in pain after recovery.

Improved function
Recovery of mobility and ability to perform daily activities.

Sustainability
Modern unicompartmental prostheses can last 10 to 15 years or more, depending on use and post-operative care.

Unicompartmental knee replacement is an effective solution for patients whose osteoarthritis is limited to a single compartment of the joint. This procedure allows for preservation of a greater portion of the natural knee joint, thus providing faster recovery and often superior functional results compared to a total knee replacement.

Arthroscopic knee osteotomy

An arthroscopic knee osteotomy is a surgical procedure to realign the bones of the knee to correct deformities and redistribute loads on the joint. This procedure is particularly useful for patients with unicompartmental osteoarthritis with knee deformities, such as genu varum (bow legs) or genu valgum (knuckle-jointed legs).
Osteotomy allows body weight to be shifted to the healthy part of the joint, thus delaying the need for a total knee replacement.

Indications
Preparation
Procedure

Indications for Knee Osteotomy

Unicompartmental osteoarthritis
Osteoarthritis limited to a single compartment of the knee (medial or lateral).

Angular deformations
Genu varum or genu valgum resulting in uneven distribution of loads on the knee.

Ligament integrity
Anterior and posterior cruciate ligaments intact and functional.

Young and active patients
Preferably for younger, active patients who wish to delay total knee replacement.

Preparation for intervention

Medical assessment
– Clinical examination: Assessment of general health and knee function.
– Imaging: X-rays, MRI or CT scan to assess the extent of joint damage and determine the angle of deformity to be corrected.

Physical preparation
– Preoperative rehabilitation: Exercises to strengthen the muscles around the knee and improve mobility.
– Stopping certain medications: Medication adjustments, particularly anticoagulants.

Surgical procedure

 

Anesthesia
– General anesthesia: The patient is completely asleep.
– Spinal/epidural anesthesia: The patient is awake but the lower body region is numb.

Arthroscopy
– Introduction of the arthroscope: An arthroscope (optical instrument) is inserted through small incisions to visualize the inside of the joint.
– Assessment and treatment of intra-articular lesions: Meniscal or cartilaginous lesions can be treated before osteotomy.

 

Osteotomy
– Incision and preparation: An incision is made on the side of the knee (medial or lateral) depending on the correction needed.
– Osteotomy: A controlled cut is made in the bone (tibia or femur) to allow realignment. For a genu varum, the osteotomy is usually performed on the tibia (high tibial osteotomy), and for a genu valgum, it is performed on the femur (femoral osteotomy).
– Angular correction: The bone is realigned to correct the deformity, thus redistributing the load towards the healthy part of the joint.

Fixing

– Plates and screws: Metal plates and screws are used to hold the bone in its new position until it heals.

Closing
– The incisions are closed with sutures or staples.
– A drain may be placed to prevent fluid buildup in the joint.

Rehabilitation and Recovery
– Hospitalization: The average length of stay is a few days.
Immediate postoperative care includes pain management and prevention of complications (infections, thromboembolism).
– Physiotherapy:
Immediate start of rehabilitation to restore knee mobility and strength.
Specific exercises are prescribed to improve flexion, extension and stability of the joint.
– Gradual resumption of activities:
Walking with crutches is usually necessary for several weeks.
Full resumption of normal activities may take several months.

Benefits of Knee Osteotomy
– Pain relief: Significant reduction in pain by diverting the load to the healthy part of the joint.
– Preservation of the joint: Delay in the need for total knee replacement.
– Improved function: Recovery of mobility and ability to perform daily activities.

Potential Complications
– Infections: Risk of infection of the joint or incision.
– Deep vein thrombosis: Formation of blood clots in the legs.
– Nonunion or malunion: The bone may not heal properly, requiring reoperation.
– Stiffness: Loss of joint mobility.

Expected Results
– Pain relief: The majority of patients experience a significant reduction in pain after recovery.
– Improved function: Recovery of mobility and ability to perform daily activities.
– Durability: Results can last for many years, providing an improved quality of life before more radical intervention is necessary.

Arthroscopic knee osteotomy is an effective procedure for treating unicompartmental knee deformities and osteoarthritis, providing a short- to medium-term alternative before the eventual placement of a total knee replacement.