What is a Knee Replacement?

The knee joint is an important weight-bearing joint of the lower limbs, and its structure and function are the most complex of human joints. Knee joint degenerative osteoarthropathy is a common disease in the elderly. Symptoms of knee osteoarthrosis in men over 50 years of age are reported to be 35% in men and 74% in women. More and more patients with severe knee osteoarthropathy require artificial knee replacement. Knee replacement can relieve knee pain, improve knee function, correct knee deformities and achieve long-term stability.

Basic Information

Chinese name: Knee replacement
Anesthesia: General anesthesia, spinal anesthesia, epidural anesthesia

Indication: Knee joint disease ineffective in conservative treatment
complication: Deep venous thrombosis, limited joint mobility, infection

Knee replacement anesthesia

General anesthesia, local anesthesia, epidural, spinal anesthesia, combined spinal epidural.

Preoperative preparation for knee replacement

1. General preparation: blood, urine, stool routine, blood biochemistry, blood coagulation, full set before blood transfusion, electrocardiogram, chest X-ray, B-ultrasound, etc.

2. Special preparations: Physical examination: Assess the condition of soft tissues: Is the skin infected? Scar contracture? Knee joint mobility, tension of medial and lateral collateral ligaments, presence of varus and valgus deformities, and limited range of joint motion. Color Doppler ultrasound of lower limbs. Risk of lower extremity blood flow is assessed for long periods of time. X-ray films: full length of the lower extremity weight-bearing position, lateral position of the knee joint, and sacrum axial position.

3. Select the size of the prosthesis according to the pre-operative X-ray measurement. Find out if medications often taken before surgery, such as aspirin or other non-steroidal anti-inflammatory drugs, or long-term use of anticoagulants, need to be discontinued before surgery.

4. Explain the purpose of the operation to patients and their families, enhance the patient's confidence in the operation, and actively cooperate with the treatment.

5. Preoperative skin preparation, blood transfusion preparation, drug skin test, etc. Fasting for 8 hours and drinking water for 4 hours before surgery to prevent suffocation or aspiration pneumonia caused by vomiting during surgery.

Indications for knee replacement

It is suitable for patients with refractory pain caused by knee joint lesions for various reasons, which is ineffective after various conservative treatments.

1. Indications for absolute surgery: knee osteoarthritis over 55 years of age; rheumatoid arthritis; traumatic arthritis; severe pain and / or dysfunction caused by bone ischemic necrosis or tumor .

2. Relative surgical indications: unstable knee joint; stiffness or deformity.

Specific conditions: clear X-ray or CT image changes of the knee joint surface. The joint function is obviously limited, which affects life. moderate to severe persistent pain, long-term conservative treatment can not effectively improve. The patient has urgent needs and psychological preparation for long-term recovery.

Contraindications of knee replacement

1. Absolute contraindications: active infection; flexor dysfunction, unable to actively bend the knee; asymptomatic knee joint rigidity; neuroarthritis.

2. Relative contraindications: a history of osteomyelitis of the femur and tibia; obvious insufficient blood supply to the knee joint; patients with excessive physical or occupational requirements; poor general conditions, severe osteoporosis, and obesity.

Mainly local or systemic infections, extreme muscle atrophy around the knee joint, extremely serious cardiopulmonary and other systemic diseases and neurodystrophic arthropathy. Obesity, younger age, and patient inability to cooperate are contraindications to relative surgery.

Knee replacement surgery steps

1. Incision revealed: In the past, the midline incision was most commonly used. In addition, there are: lateral paracondylar incision, medial lateral paracondylar incision, lateral lateral paracondylar incision, medial paracondylar incision, medial paracondylar incision, lateral approach to the knee joint, and medial access to the quadriceps.

2. Relief of soft tissues: For varus deformity, valgus deformity, and fixed contracture deformity, the corresponding release technique is implemented.

3. Osteotomy: flexion and extension of the knee space technology, joint line technology, use of guides.

4. Handle the sacrum: Maintain the correct position and trajectory.

5. Implantation.

6. Place drainage and close the incision.

Knee replacement complications

1. Postoperative pain.

2. Deep vein thrombosis.

3. The prosthesis is loose.

4. Periprosthetic fractures: including tibial fractures, femoral fractures, and patella fractures.

5. Poor incision healing.

6. The knee joint is stiff and has limited movement.

7. Periprosthetic infection.

8. Biomechanical instability of the knee joint.

Nursing after knee replacement

1. Apply antibiotics for 7 to 10 days after operation to prevent infection.

2. After the supine pillow is supine and supine for 6 hours, the soft pillow is lifted and the neutral position is maintained to avoid excessive compression of the gastrocnemius and common peroneal nerve.

3. Fix the drainage tube to prevent it from being pulled, twisted and folded, and prevent it from falling off.

4. Observe the sensory movements of the affected limbs, keep the ankle joint neutral, and prevent the foot from sagging.

5. Observe the limbs for swelling, abnormal skin, temperature, color and feeling at the extremities to prevent the occurrence of deep vein thrombosis.

6. According to the drainage situation, drainage is generally removed 48 hours after surgery, sutures are removed for 2 weeks, and walking with crutches is practiced.

Knee replacement rehabilitation training

1. On the day after the operation, raise the heels and raise the affected limbs to rest and avoid pressure ulcers.

2. On the first day after surgery, perform isometric contraction exercises for the quadriceps and hamstrings. Raise the affected limb at rest.

3. On the 2nd to 4th day after the operation, continue the passive activity exercise, the initial range of activity is 0 ° ~ 45 °, 2 times a day, 1 hour each time. And perform joint mobility exercises.

4. On the 5th to 6th day after the operation, begin balancing and coordinating exercises.

5. On the 7th day after surgery, practice walking with walking sticks or walking.

6. In the 2nd week after operation, the CPM flexion and extension gradually increased to 0 ° ~ 90 °, and the range of knee flexion could reach 90 ° within 2 weeks after operation. Perform resistance exercises for the isotonic contraction exercises of the quadriceps femoris muscles and the occipital muscles, exercise of functional bicycles, and go up and down the stairs as appropriate.

7. In the third week after the operation, increase squat exercises.

8. Three to six weeks after the operation, the main purpose is to strengthen muscle strength, and continue to exercise joint mobility, while continuing to improve walking ability, fully load.