Osteoarthritis (OA) is classically thought of as a degenerative ‘wear and tear’ arthritis whereby the articular cartilage that serves to protect the ends of the bones at a joint by reducing friction and compressive forces so they can easily glide over one another is gradually worn away. As this occurs, the bone ends roughen and the joint spaces decrease, meaning the bones of the joint are susceptible to rubbing against one another, causing thickening of the bone, increase in inflammatory markers with in joints and painful bone spurs. Symptoms typically include pain, joint stiffness and inflammation, with the enzymes involved in this inflammatory process potentially causing further damage to the cartilage due to their by-products. While most often prevalent in the ageing population, osteoarthritis can also be present in younger individuals and is also attributed to by a family history of the condition, obesity, injury, overloaded bony malalignment and overuse.
- Hallux (big toe) OA - also known as Hallux Rigidus, the big toe is one of the most common sites of arthritis in the foot due to the high impact repetitively absorbed by the big toe during physical activity and repeated trauma, particularly in physically active individuals. The result is pain, swelling and worsening stiffness until there is very limited or no movement available at the big toe joint. It often presents with a hallux valgus (bunion) deformity. Because the ability of the big toe to dorsiflex (bend upwards) is an essential component of gait, it is imperative that this OA is effectively managed and that management is appropriate to the stage of degeneration.
- Subtalar joint (STJ) OA - The STJ is primarily responsible for inversion and eversion of the rearfoot, that is, being able to point the foot inwards and outwards - a critical component of gait. It is a relatively stable joint comprised of talus and calcaneus (heel) bones with supporting ligaments (interosseous and cervical). Because inversion/eversion is essential for adapting to uneven terrain and proprioceptive function, there is a significantly increased falls risk for individuals with OA. STJ OA most commonly occurs following a trauma such as a talus or intra-articular calcaneus fracture. Biomechanical rearfoot deformities can also contribute to STJ OA. Symptoms include rearfoot pain, swelling and joint stiffness.
- Talocrural joint (TCJ) OA - The talocrural (ankle) joint is a hinge joint that involves the tibia, fibula and talus bones. It allows the ankle to move down into plantarflexion (pointing the foot downward) and dorsiflexion (pointing the foot upward). Of all of the joints in the body, the ankle absorbs the greatest force per square centimetre so is vulnerable to the degenerative effects of OA. The onset of ankle OA is most commonly post-traumatic, including fractures, chronic ankle instability with recurrent sprains and osteochondral (bone-cartilage) injuries. Early stage ankle OA presents with mild to moderate pain and swelling after repetitive high-impact activities and prolonged weight-bearing. With the progression of degeneration, stiffness in the joint increases and the occurrence of pain becomes more frequent and severe, presenting throughout most of the day including periods of rest. With regards to the joint itself, as the OA progresses, the ankle joint spaces will narrow and osteophytes (bony spurs) will develop. At the end stage of ankle OA, no joint space may be left and a deformity may result where the heel remains in a valgus (pointed outwards) or varus (pointed inwards) position. Ultimately, the ability to walk comfortably and for prolonged periods is impaired and impacts an individual’s overall quality of life, so effective management is a priority.
Knee OA - Knee Osteoarthritis describes the ‘wear and tear’ degeneration of the cartilaginous ends of the knee joint which consists of the femur (thigh bone), the tibia (shin) and the patella (knee cap). The cartilage becomes rough and without its protection, the joint spaces decrease and bones can rub against one another and produce osteophytes (bony spurs). Because our knees take a heavy load with every step, the knee is a common osteoarthritic joint. Pain and swelling in the knee worsen over time due to further imbalance of inflammatory and antiinflammatory mediators, especially on walking and physical activities, and the available motion at the joint decreases alongside knee stability. This stiffness can make it difficult to walk and individuals may take on an altered gait (abnormal walking style) to try to compensate for their knee pain and limitations. Knee OA most commonly occurs over the age of 50 due to a life time of use, but may also occur at an earlier age and may be attributed to by previous trauma, increased BMI, family history of OA, the female gender and some inflammatory conditions.