Knee arthritis is a very common condition that affects many Australians. The term arthritis is an umbrella term which means inflammation of one or more joints within the musculoskeletal system. The knee is one of the most frequently affected regions of the body. While there are more than 100 conditions that fall under the umbrella of ‘arthritis’, the most common are listed below.
Types of Knee Arthritis
The most common form of arthritis is Osteoarthitis, which is a degenerative process affecting the joint cartilage (‘articular cartilage’) and underlying bone. It occurs when the protective cartilage over the ends of the bone, wears down over time. This is typically slowly progressive in nature, and seen most frequently in middle to older aged patients.
Rheumatoid arthritis is the most common autoimmune arthritis. This condition results in inflammation of the lining of the joint (‘Synovium’). With time, an inflammatory cascade occurs with resultant destruction of the joint surfaces. It is seen more frequently in women and often involves multiple joints.
Post-traumatic arthritis occurs following one or more injuries to the knee. This group of patients are likely to be younger, and the condition may develop after:
- A fracture (broken bone) around the knee joint
- A meniscus tear Have link to meniscus tear page
- A ligament tear (i.e ACL injury) Have link to ACL Injury page
This is a relatively uncommon form of arthritis that occurs due to an infection (typically bacterial) inside the knee joint. The bacteria and the resultant inflammation destroy the joint cartilage. In the acute setting, this conditions requires an urgent washout via an arthroscopy to get control of the infection.
Knee arthritis is a major debilitating conditions that can make it very hard for people to do everyday activities. Common symptoms include pain, swelling, and stiffness, which fluctuate with time. In the early phases of knee arthritis, symptoms may only be noticed during periods of exercise. As the condition progresses, it is common to experience pain at rest (i.e while sitting), or at night. This frequently results in a reduced walking distance. A ‘giving way’ sensation and pain that fluctuates with weather changes are also common.
Three compartments in the knee joint
The knee joint is comprised of three compartments. A medial (inner) compartment, a Lateral (outer) compartment, and a Patellofemoral (‘knee cap’) compartment. While arthritis commonly affects all three compartments, it can also be isolated to one or two of the above areas. The location of the arthritis within the knee joint, helps dictate management (See below).
Knee arthritis- Making the diagnosis
The diagnosis of knee arthritis is made following a detailed history, a thorough physical examination, and further imaging. You will be asked about what symptoms you are experiencing, the severity of these symptoms, and how it is affecting your work or recreational life. An examination takes place to assess sites of tenderness, restriction in range of movement, and the integrity of the surrounding ligaments.
Plain xrays are taken to confirm the diagnosis and severity of the arthritis. While surface cartilage does not show up on plain xrays, we are able to assess the ‘joint space’ between the two bones, and the less space available, the more advanced the arthritis. An MRI may be required in more subtle cases, and to assess the other structures within the knee joint, such as the meniscus.
Nonoperative Management of knee arthritis
Nonoperative options for managing arthritis include:
- Simple analgesia – paracetamol / Anti-inflammatories
- Lifestyle modifications – Reduced participation in high impact (running, jumping) sports
- Weight loss if appropriate
- Low impact exercises – Walking, Swimming, Cycling
Operative Management of knee arthritis
Surgical options for knee arthritis depend on many factors. These include the location/compartment affected by the arthritis, and the age and function of the patient. Dr. Smith strongly believes in creating a tailored management plan after discussing all options with the patient.
Total knee replacements are the gold standard for surgically managing knee arthritis. Dr. Smith performs this procedure using specialized computer navigation or patient specific technology. This option is most appropriate for middle to older aged patients who have more than one compartment affected by the arthritis.
A Partial Knee Replacement involves only replacing the compartment affected by arthritis. This is most commonly performed for the medial (inner) compartment, but can also be done for the lateral (outer) or patellofemoral compartment. Dr. Smith will discuss the potential benefits and considerations for these procedures.
In a select group of young patients (< 40 years old) with localised arthritis, a corrective osteotomy may be a valid treatment option. This procedure involves surgically cutting the bone and re-aligning it, to reduce the pressure that goes through a certain compartment of the knee, to relieve symptoms.
In patients with a combination of early arthritis and an acute meniscal tear, an arthroscopy is an option designed to partially resect the meniscus tear, back to a stable base, and relieve the sharp ‘catching’ pain that the patient was experiencing.