In the skeleton, where bones meet is known as a joint. Our joints can be classified as follows:
- Fibrous i.e., a fixed joint where fibrous tissue connects bone. These are generally not a location of movement, with no joint cavity. Examples of fibrous joints include the sutures holding together the different bones that comprise the skull.
- Cartilaginous i.e., a joint where bones are joined by hyaline cartilage or fibrocartilage, and may have some mobility. An example of a cartilaginous joint is the pubic symphysis in the pelvis.
- Synovial i.e., freely moving joints. These are the main joints in terms of allowing our body to move freely and are the joints of concern in osteoarthritis.
What is a synovial joint?
Synovial joints are designed to enable free, painless movement, by preventing friction between articulating joints. Synovial joints are characterised by the presence of a joint cavity. The joint cavity connects the adjoining bones via an articular capsule. Lining the inside of the articular capsule is a membrane called the synovium, which secretes the lubricating, nutritional synovial fluid. The surface of the articulating bones is covered with hyaline cartilage.
Synovial joints can be further classified, for example:
- Hinge joint e.g., the elbow, knee, or ankle.
- Condyloid joint e.g., the fingers.
- Ball and socket joint e.g., the hip and shoulder.
What is osteoarthritis?
Classically considered as “wear and tear”, osteoarthritis is a condition of progressive degradation of cartilage and bone remodelling at the synovial joint. The disease develops when the cartilage cells respond to damage, leading to an inflammatory process and further breakdown of the articular cartilage. Consequently, the underlying bone becomes exposed and reacts, leading to remodelling.
On X-ray, the radiological appearances classically reveal:
- Reduced joint space
- Osteophytes – boney spurs that grow from the bones at the joint.
- Subchondral cysts – a fluid filled cavity present in the bone beneath the articular surface.
- Subchondral sclerosis – bone thickening at the articular surface.
What are the risk factors for osteoarthritis?
- Advancing age
- Manual labour
- High impact sports
- Trauma to the joint
What are the symptoms of osteoarthritis?
Most commonly affecting the fingers, toes, hips, and knees, osteoarthritis usually presents as joint pain and stiffness that:
- Worsens with activity
- Improves with rest
- Becomes gradually worse over time
Over time, joint deformities develop, such as Heberden nodes and Bouchard nodes in the fingers, and fixed flexion.
How is osteoarthritis managed?
Osteoarthritis can be managed conservatively, medically, or surgically.
Conservative treatment of osteoarthritis includes:
- Weight loss
- Joint supports
Medical treatment of osteoarthritis involves the prescription of analgesics and topical anti-inflammatory creams. Patients may also be offered intra-articular steroid injections.
Should conservative and medical treatments no longer be effective, and an individual’s quality of life is significantly affected, a patient can be offered surgical intervention in the form of:
- Osteotomy – cutting and re-shaping bone to relieve pressure from one area of the joint.
- Arthrodesis – fusing the joint to limit movement.
- Arthroplasty – either resurfacing of the bone or replacing the joint.
The hip joint is a ball and socket type synovial joint comprised of the acetabulum (socket) and femoral head (ball). Surgical treatment for osteoarthritis of the hip includes:
- Hip resurfacing – the femoral head is resurfaced and covered with a metal cap.
- Total hip replacement – the femoral head is replaced and a metal cup is attached to the acetabulum.
- Partial hip replacement – only the femoral head is replaced.
A hip replacement can be approached from three difference angles:
- From the front – anterior hip replacement
- From the back – posterior hip replacement
- From the side – lateral hip replacement
The femoral head is replaced with a ceramic ball attached to a metal stem which is implanted into the femur. The metal cup which goes into the acetabulum is usually made of titanium with an inner plastic layer; the socket may attach to the acetabulum via a porous surface (uncemented) or with bone cement.
With a deep understanding of NICE guidelines and correct treatment pathways, in combination with a superb level of surgical expertise, our Expert Witnesses in hip surgery can advise on breach of duty, causation, current condition, and prognosis, in individuals who have undergone or require hip surgery.
The knee joint is a hinge type of synovial joint where the tibia and femur meet. The joint is held together by numerous ligaments including:
- Patellar ligament
- Collateral ligaments
- Cruciate ligaments
The knee joint also contains a medial meniscus and lateral meniscus, which are fibrocartilaginous structures that act as shock absorbers. Overlying the knee joint is the quadriceps femoris tendon which contains the patella. This acts to increase the power of the knee, stabilises the knee, and reduces friction.
Surgical intervention for osteoarthritis of the knee includes:
- Total knee replacement
- Partial knee replacement
- Knee osteotomy
- Knee arthroscopy
- Repair and restoration of cartilage e.g., meniscectomy
With a deep understanding of NICE guidelines and correct treatment pathways, in combination with a superb level of surgical expertise, our Expert Witnesses in knee surgery can advise on breach of duty, causation, current condition, and prognosis, in individuals who have undergone or require knee surgery.