Osteoarthritis of the knee

Painful and disabling, knee osteoarthritis often represents the first reason for complaints related to osteoarthritis.

It is a joint disease characterized by degradation of the cartilage.

Knee osteoarthritis (cartilage wear)

The frequency of osteoarthritis increases with age, but it is not a disease of the elderly in the sense that most people are still active at the time of diagnosis.

The four main risk factors for osteoarthritis of the knee include:

congenital disorders of the lower limbs, such as genu varum or genu valgum malalignment;

Different lower limbs morphotypes

trauma (meniscus surgery, chronic cruciate ligament rupture, etc.) and, in some professions, repetitive strain injury (tilers, top athletes who overuse their support legs , etc.);
excess weight and obesity;
aging, which makes the joint less resistant;

Clinical presentation and radiological diagnosis:

Pain, sometimes accompanied by swelling, is the main symptom of knee OA. Stiffness is another common clinical sign. Simple standing x-rays are generally sufficient to confirm the diagnosis.

normal knee

moderate osteoarthritis

advanced osteoarthritis

These images demonstrate thinner cartilage and less free space between the bones. Large deformations can sometimes be observed when the osteoarthritis is advanced.

The treatment of knee osteoarthritis:

The treatment of knee osteoarthritis is performed in steps according to the severity of the condition and complaints.

Weight reduction (in the case of excess weight) and the practice of adapted sports.
Physiotherapy: it helps to limit stiffness and strengthen the thigh to stabilize the joint.
Use of insoles: custom made, they are sometimes prescribed to correct an overpressure on one side of the knee and thus relieve pain. They will, for example, be thicker externally to discharge a pinched joint on the internal side. In all cases, it is better to use flexible shoes and avoid high heels.
Wearing orthotics (knee brace): Wearing a knee brace can also facilitate walking if there are feelings of instability. During severe pain, leaning on a cane, held on the side opposite the painful knee.
Drug treatment
- Non-steroidal anti-inflammatory drugs (eg Diclofenac): are affective in relieving pain provided there are no gastric or cardiovascular contraindications.
- The slow-acting “antiarthritis” represented by glucosamine and chondroitin sulfate have little or no undesirable effects, but their effectiveness remains disputed.
- Intra-articular injections of corticosteroids and / or hyaluronic acids
Surgical treatment: Surgery does not necessarily mean knee prosthesis. When osteoarthritis occurs on a genu varum or genu valgum and is not yet too advanced, the surgeon can perform tibial osteotomy (more rarely femoral). The operation consists of removing a fragment of the tibia to modify its axis and distribute the body’s weight more fairly over the joint. In proper scenarios, osteotomies offer good results at ten years follow up and sometimes make the implementation of a prosthesis unnecessary.

Total knee replacement:

The artificial implant that is used to replace damaged areas of the knee joint is called a knee prosthesis. The procedure is also called prosthetic knee replacement surgery. The total knee prosthesis is made up of 4 pieces: tibial and femoral (metallic) components, polyethylene (between the two metallic pieces), and a patellar button.

Total knee prosthesis

This operation has considerably improved the quality of life of patients suffering from advanced osteoarthritis, who are no longer relieved by medical treatments, or by inflammatory diseases such as polyarthritis. Advances in implants as well as improved surgical techniques and post-operative pain management have significantly contributed to the quality of current results in knee function and pain. The lifetime of a prosthesis is now on average 15 to 18 years.

The duration of hospitalization is approximately 3 to 5 days. Rehabilitation of the operated knee as well as walking are started from the first or second day after the operation and is continued for approximately 2 months after discharge. Usually the recovery time for a correct function is around the 3rd month post-operatively and a steady situation is achieved between the 6th and 12th month postoperatively.

Partial prostheses (uni-compartmental prosthesis) are reserved for arthritis limited to one compartment of the joint, most often the internal compartment of the knee.

Partial knee prosthesis (hemi-prosthesis)

Early post-operative complications:

• Infection is a feared complication because it is potentially serious. It is a uncommon, and occurs in, less than 1% of cases based on currents studies. All precautions must be taken (compliance with aseptic measures, a thorough preoperative assessment aimed at finding any infectious sources on the patient in order to eradicate them before the intervention).
• Deep vein thrombosis. This complication is potentially serious because it can develop into a pulmonary embolism. Prevention is with post-operative anticoagulants.
• Hematoma. This can be normal (mild and of small volume) or much larger corresponding to active bleeding and sometimes requires re-intervention for evacuation
• Algodystrophy is a rare and unexplained complication that can cause stiffness, pain, and edema which ultimately slow down functional recovery. It is a dysregulation of the autonomic nervous system and the available treatments are not very affective. Algodystrophy can last for several months and disappears spontaneously. During this period, no aggressive knee treatment or surgical intervention will be undertaken, except in emergent cases
• Knee stiffness can occur after any knee surgery, and in particular after a total knee prosthesis. Adhesions can form in the joint leading to mobility restrictions. Various causes of stiffness include postoperative pain, hematoma, infection (rare), inappropriate rehabilitation, inflammation, or algodystrophy. By nature, everyone reacts differently to tissue scarring after knee surgery and some patients will develop these kinds of complications slowing recovery. Knee mobilization under anesthesia may be necessary to improve mobility and pain. The goal is to break down scar tissue at the latest a few weeks after the intervention.

Midterm and long term complications:

These include late infections, chronic stiffness, and loosening of the prosthesis:
• Late infection is very rare and occurs most often secondary to a distant infection which subsequently spreads to the prosthesis. Examples of this include a dental abscess, urinary tract infection, digestive tract infection, skin infection etc..It is therefore important that any patient with a knee prosthesis be treated adequately for any infection and followed by a doctor who is aware of the patient’s implant. The treatment of these late infections may require re-intervention to replace the prosthesis and a long course of antibiotic therapy
• Chronic stiffness is rare and difficult to treat.
• loosening of the prosthesis leads to more pain or pain that is less well tolerated. This is often associated with wear of the prosthesis and increases with age of the prosthesis and the degree of stress imposed on it (heavy physical activity, overweight). On average, loosening occurs approximately 18 years after the operation and may require reoperation for replacement of the prosthesis.