Overview
Post-traumatic arthritis involves pain and inflammation of the joints following injury, such as bone dislocation or fracture. Changes to joint stability mean a joint is more likely to suffer further dislocations or injuries. An important part of post-traumatic arthritis recovery is restoring joint stability.
What is arthritis?
Arthritis is a common condition which causes pain and inflammation in the joints. The suffix “itis” means inflamed. There are many types and causes of arthritis, leading to symptoms such as swelling and immobility. Two of the most common types are compared in the table below:
Osteoarthritis (OA) | Rheumatoid arthritis (RA) |
This is the most common form of arthritis, affecting 10 million people in the UK - 5.4 million have knee OA - 3.2 million have hip OA - Globally 7.6% of the population are affected (2020)1 | About 1% of people in the UK and globally have RA, making this less common than OA |
Affects 4 million people assigned male at birth(AMAB) in the UK compared to 6 million people assigned female at birth(AFAB). | Affects 1.5 million people assigned male at birth and 3.6 million people assigned female at birth per 10,000 in the UK |
OA is likely to start in one area and be localised to one side, for example following trauma or injury. Around 12% of OA cases are caused by an injury (acute trauma) 2 | RA tends to occur symmetrically, often starting with symptoms in the hands and feet |
The average age of onset is 55 years old. OA is degenerative, gradually worsening with age over time. However, post-traumatic OA may occur in younger patients due to joint injury. | RA’s average age of onset is between 30 and 50 years old. As an autoimmune, inflammatory disorder, RA can ‘flare up’ and later go into remission, whereas OA causes more constant, consistent symptoms. |
Key symptoms of post-traumatic arthritis
- Swollen joint (fluid build-up)
- Stiffness of the joint and difficulty moving
- Severe pain at the site of the injury
- Difficulty putting weight or pressure on the joint
Understanding post-traumatic arthritis
Post-traumatic arthritis occurs after trauma such as a dislocation or broken bone. This can often be a temporary condition which occurs immediately after the injury and heals after several months. Alternatively, post-traumatic arthritis can become chronic, long-term osteoarthritis which worsens with time.
Causes and risk factors
Post-traumatic arthritis is caused by acute trauma to a joint or the supporting tissues around the joint. The damage may involve tearing or bruising. The tissues around the joint which are susceptible to injury which may lead to later arthritis include:
- Ligaments (connective tissue between and joining bones)
- Menisci (cartilage which supports knee joints and acts as a cushion to absorb shocks)
- Articular cartilage (a thin layer of smooth, elastic cartilage covering the bony surface of the joint)
- The synovial membrane (a thin barrier layer in the joint cavity) which secretes synovial fluid, keeping the joint lubricated
- The bone itself
Risk factors
- Being assigned female at birth (AFAB) is a risk factor for post-traumatic arthritis, as illustrated by the statistics in the table above
- Low oestrogen, associated with menopause, increases the risk for OA and post-traumatic arthritis
- Chronic dislocation (long-term, repeated dislocation) of a joint increases the risk of the development of arthritis due to severe joint instability
- An unstable kneecap (trochlear dysplasia) increases the risk of developing knee OA
- Tears in the cartilage over a joint, known as osteochondral lesions can occur in the knee or ankle and lead to post-traumatic arthritis
- Repeated mechanical stress to joints, for example through intense sport, accelerates joint degeneration
- Obesity increases the load and stress on the joints, and impairs wound healing, increasing the risk of post-traumatic arthritis
Pathophysiology
Injury (or acute trauma) to the joint and its supporting tissues can cause structural damage to the joint, preventing smooth movement and affecting the mobility of the joint. Additionally, the injury causes inflammation and swelling. Oedema (a build-up of fluid creating the swelling) can also affect the mobility of the joint, making movement difficult and painful.
As the body responds to the injury, an accumulation of white blood cells at the joint leads to increased reactive oxygen species (which damage cells) and cytokines (chemical signals that work to increase inflammation).3
Chondrocytes (cartilage cells at the joint) can be dysfunctional and undergo cell death called apoptosis in response to the inflammatory signals.4
Commonly affected joints and tissues
The anterior cruciate ligament (ACL), a ligament in the knee, is a strong band which holds your knee joint’s bones and cartilage together. This ligament is commonly injured through actions such as running, twisting the leg, landing poorly from a jump, or falling over. Many patients develop post-traumatic arthritis after injury to the ACL.
Arthritis of the hip often occurs following fractures of the femoral neck (the top of the thigh bone) or fractures of the acetabulum (hip socket), as well as dislocations, or impact injuries such as falling. The cartilage damage often leads to post-injury arthritis.
Ankle arthritis may occur following ankle sprains or breaking lower leg bones – fractures of the tibia and fibula. This may be due to spraining the ankle whilst walking, running or playing sports, or due to damage inflicted in an incident such as a car collision. Some patients may develop ‘bone spurs’ which protrude from the ankle, causing further pain.
The importance of joint stability
Joint stability refers to how much a joint can remain in its correct alignment despite pressures or movement forcing it out of alignment. In other words, the more stable a joint, the more it can resist dislocation.
How trauma affects joint stability
Ligamentous support
The original injury might disrupt or damage ligaments which are crucial for holding the joint in position and keeping it stable. Damage to the ligaments, in addition to the shock-absorbing cartilage or other supporting tissues, means that high-pressure impacts disrupt the joint position more than usual, thus reducing joint stability further.
Muscular support
The pain and immobility associated with an injury can lead to reduced movement, and consequent muscle weakness and wasting. Weaker muscles are then also less able to support joint stability. Imbalances caused by muscle weakness also make further injury more likely.
Neurological damage
The injury could damage nerves around the joint, leading to nerve pain as well as difficulty in controlling and coordinating muscles as required for the usual support and stability of the joint.
The role of proprioception
Proprioception refers to the body’s ability to sense the body’s movement and position. Nerve damage could impair your proprioception in that area of the body, meaning that you are unaware of your joints, accurate limb location and usual sensations. This reduces your ability to keep the joint stable to avoid discomfort or dislocation.
Assessment of joint stability in post-traumatic arthritis patients
Joint stability can be measured through physical tests (known as kinematic measurements) or via electromyography, where electrodes are attached to the muscles to measure muscle response to nerve stimulation. A common kinematic test which measures the stability of the knee is via challenging walking conditions, called ‘challenged gait’. For example, the patient’s ability to walk downhill may be recorded.5
Rehabilitation strategies for enhancing joint stability
Rehabilitation is an important part of therapy to address joint stability in post-traumatic arthritis. Initially, the joint is unlikely to be able to withstand strong exercise or pressure, so the focus is on gently moving as much as possible to prevent stiffness. This also increases circulation to the affected area, promoting healing, and reducing complications such as muscle atrophy.
The extent of mobilisation will be affected by pain, but the patient may take anti-inflammatory and pain medication to support the rehabilitation efforts.
Later on, further strengthening exercises can be carried out with a focus on increasing local muscle strength to support the joint’s alignment.
Balance training may also be used to improve proprioception and restore balance if this has been impacted following the injury.
Surgical interventions for restoring joint stability
In some cases, doctors may carry out surgery to repair ligament damage, allowing the joint to then recover with better stability. For example, reconstructive ACL surgery aims to stabilise and strengthen the knee after ACL damage. Ankle stabilisation procedures are also commonly carried out if ankle ligaments or cartilage have been severely damaged. Lateral ligaments of the ankle may be tightened to help secure the ankle or partially replaced using tendons.
Reducing the risk of post-traumatic arthritis
To reduce the risk of arthritis, there are a number of exercises, physical therapies and dietary interventions which can be employed.
Exercise
As mentioned earlier, rehabilitation can include physical therapies and exercises which can have a huge impact on arthritis symptoms. Exercises which keep all joints mobile, increase blood circulation, and keep muscles strong can reduce the risk of joint injury in the first place.
Furthermore, obesity was noted as a risk factor for arthritis. Therefore, regular exercise could be useful to maintain a healthy weight and cause less stress to joints.
Dietary interventions to prevent arthritis
An anti-inflammatory diet may be suggested to help reduce arthritic inflammation. These are foods that provide us with antioxidants – chemicals that neutralise damaging inflammatory processes in our cells. For example, foods such as apples, oranges and colourful fruits like dragon fruit are high in plant chemicals which fight inflammatory damage.
In addition to fruits and vegetables, an anti-inflammatory diet could include:
- Nuts and seeds
- Fatty fish such as salmon, contains omega-3 fatty acids
- Herbs and spices e.g. turmeric, ginger, cinnamon
- Avoiding highly processed foods and foods high in saturated fats
- Staying hydrated to reduce inflammation and support joint lubrication
Emerging technologies
Many new treatments are being researched in the field of arthritis therapy.
Monoclonal antibody drugs such as otilimab are undergoing clinical trials, which specifically block chemicals that stimulate inflammation and joint pain.6
There are also drugs that stimulate the growth of cartilage by promoting ‘growth factor’ chemical signals, thereby thickening the cartilage and allowing recovery of the damaged joint.
Summary
Post-traumatic arthritis is a condition involving inflamed, painful joints which occurs following an injury. Trauma from physical injury is likely to damage the bone, cartilage, ligaments, or other supporting tissues, compromising the stability of the joint. This leaves the joint vulnerable to further damage and increasing inflammation. Commonly the knees, ankles, shoulders and elbows can be affected by this condition.
Physical rehabilitation through exercise is an important management technique to restore joint stability and treat arthritis. Unlike other types of arthritis, post-traumatic arthritis can often be temporary and improves once the injury is healed and joint stability is restored.
References
- Global, regional, and national burden of osteoarthritis, 1990–2020 and projections to 2050 | Institute for Health Metrics and Evaluation [Internet]. [cited 2024 Sep 2]. Available from: https://www.healthdata.org/research-analysis/library/global-regional-and-national-burden-osteoarthritis-1990-2020-and.
- Punzi L, Galozzi P, Luisetto R, Favero M, Ramonda R, Oliviero F, et al. Post-traumatic arthritis: overview on pathogenic mechanisms and role of inflammation. RMD Open [Internet]. 2016 [cited 2024 Sep 2]; 2(2):e000279. Available from: https://rmdopen.bmj.com/content/2/2/e000279.
- Yunus MHM, Nordin A, Kamal H. Pathophysiological Perspective of Osteoarthritis. Medicina (Kaunas) [Internet]. 2020 [cited 2024 Sep 2]; 56(11):614. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7696673/.
- Lieberthal J, Sambamurthy N, Scanzello CR. Inflammation in Joint Injury and Post-Traumatic Osteoarthritis. Osteoarthritis Cartilage [Internet]. 2015 [cited 2024 Sep 2]; 23(11):1825–34. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4630675/.
- Schrijvers JC, van den Noort JC, van der Esch M, Dekker J, Harlaar J. Objective parameters to measure (in) stability of the knee joint during gait: A review of literature. Gait & Posture. 2019 May 1;70:235-53. Available from: https://pubmed.ncbi.nlm.nih.gov/30909003/
- Bykerk VP. The efficacy and safety of targeting GM-CSF in arthritis. Lancet Rheumatol [Internet]. 2020 [cited 2024 Sep 2]; 2(11):e648–50. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7541049/.