Total knee replacement is a surgical intervention that replaces the worn joint surfaces of the femur, tibia, and often the kneecap as a source of disabling pain. High-density polyethylene and metal components are placed in the place of damaged and painful joint surfaces.

Objectives of Surgery:

• The primary goal of a full knee replacement is to treat arthritis pain while improving joint mobility, increasing functional capacity, and restoring quality of life. In some cases, arthrosis results from a misalignment of the varus or valgus knee (bent knees or knees together, respectively), and there is a second objective for surgery, which is the correction of this anatomical deformity.
• The joint mobility to be achieved after surgery will be between 100 to 130 degrees of flexion and full extension. However, the main factor determining postoperative amplitude is the amplitude before surgery, so a knee with reduced mobility will have greater difficulty in reaching the desired amplitude.

Indications:

• All patients with indications for total arthroplasty are frankly limited to activities of daily living, suffering from severe and disabling pain, resistant to medical and physiological therapy, and without any other surgical option.
• The age factor should be assessed against the currently available statistical data, which show that total knee arthroplasty survival is 90% at 10 and 80% at 20 years (as defined by prostheses still functioning) respectively. However, the placement of knee prostheses may be proposed at younger ages, in particular clinical situations that do not have any other medical or surgical alternative that returns the patient’s quality of life.
• Most patients are in the age group above 60 years, with the upper limit nowadays being dependent on the general clinical condition, with many cases operated after 80 years. Surgical risk will always be evaluated at Preoperative Anesthesiology Consultation.
• Another important factor, regardless of age, is the motivation of the patient and their family in the face of disability and suffering caused by arthrosis, after open discussion of risks and benefits, especially if there are no serious pathologies that may condition the longevity of the patient.
• The patient indicated for this surgery most often has evolved arthrosis of idiopathic etiology (no cause is identified), mechanical by axis deviation or post-traumatic, by sequelae of joint fractures.
• Rheumatic diseases, especially rheumatoid arthritis, represent the second most important group of pathologies, due to their joint involvement.
• Excess body weight is not a contraindication as long as the patient has a general condition compatible with the surgery. The long-term results are slightly lower for surgery, however, it should be considered that obesity associated with mobility limitation is itself a vicious cycle, both for the medical pathologies it causes and for the greater body weight gain.
• The longevity of the prosthesis mentioned above motivates us to try whenever possible a more conservative surgical approach in younger patients, defined by age groups below 60 years of age. This approach consists of arthroscopic gestures, osteotomies for axis correction (“straighten crooked legs”), or even physiotherapy associated with medication and infiltrations in the context of regenerative medicine.

Complications / Risks:

• Performing an arthroplasty involves risks that should be known to the patient. Possible postoperative complications include thromboembolism, which motivates mandatory pharmacological prevention, skin complications, and neurovascular lesions. Infection often referred to as rejection, has an incidence of less than 1%, but may require further prosthesis lavage and replacement surgery.
• Arthroplasty failure may be due to aseptic detachment (loose components in the absence of infection, due to sensitivity to polyethylene wear) and premature wear of the material. In these cases, it also implies a new surgery for its revision/replacement.

Surgical technique:

• The surgical technique we use today is called minimally invasive. It consists in the use of smaller skin incisions, but above all in less aggression of the surrounding soft tissues (muscles, synovial membrane, ligaments, vessels, and nerves).
• This approach allows for a less painful postoperative period, less blood loss, lower risk of infection, and faster and less painful recovery. Most patients can, after an initial period with support and load of the operated lower limb, with 2 crutches, resume an unaided gait for 1–2 months, depending on the condition of the contralateral knee.
• In performing this surgery, general or locoregional anesthesia may be used, depending on the decision of the patient and anesthetist, during the Anesthesiology Consultation.
• The rehabilitation program begins during hospitalization, about 48 hours after surgery, leaving the patient to walk with the help of 2 Canadians and able to go up and downstairs.

Postoperative Care:

• The placement of a knee arthroplasty implies limitations for sports practice and should avoid activities with impact. However, walking, golf, gym, swimming, dancing, and cycling are permitted. Patients should promote the longevity of their prostheses, avoiding overweight, intense physical impact (running), heavy loads, and hyperflexion postures.
• Any infection that occurs anywhere in the body should be treated early and effectively because of the risk of bacteremia (bacteria circulating in the bloodstream) that can remotely contaminate the knee prosthesis. For the same reason, antibiotic prevention should be systematically carried out in all dental or endoscopic manipulations and should be consulted by your treating physician as necessary.

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