From the Guidelines
Charcot joint is primarily caused by peripheral neuropathy, most commonly diabetic neuropathy, which leads to an inflammatory process resulting in injury to bones, joints, and soft tissues. According to the most recent guidelines on the diagnosis and treatment of active Charcot neuro-osteoarthropathy in persons with diabetes mellitus [IWGDF 2023] 1, Charcot neuro-osteoarthropathy (CNO) is viewed as an inflammatory process in persons with peripheral polyneuropathy. The etiology of Charcot joint can be attributed to various factors, including:
- Diabetic neuropathy, which is the most common cause
- Other forms of peripheral neuropathy, such as tabes dorsalis (syphilitic neuropathy), syringomyelia, spinal cord injury, leprosy, alcoholic neuropathy, and congenital insensitivity to pain
- The pathophysiology involves two main mechanisms: neurovascular and neurotraumatic, with the neurovascular theory suggesting that autonomic neuropathy causes increased blood flow to the joint, leading to bone resorption and weakening, and the neurotraumatic theory suggesting that repeated microtrauma to an insensate joint causes progressive damage [as implied by 1].
The loss of proprioception and protective pain mechanisms allows patients to continue weight-bearing on damaged joints, exacerbating the condition, and early recognition is crucial as the condition progresses through inflammatory, developmental, and late reconstructive phases, with each stage presenting increasing levels of joint destruction and deformity 1. It is essential to note that patient-reported health-related quality of life is negatively impacted by CNO, and after the resolution of the inflammatory phase, CNO can result in permanent deformity of the foot and/or ankle, predisposing to ulceration and infection, which significantly increase the risk of major lower extremity amputation 1.
From the Research
Etiology of Charcot Joint
The etiology of Charcot joint, also known as neuropathic osteoarthropathy, is a complex process involving multiple factors. Some of the key factors include:
- Neuropathy: Charcot joint is often associated with peripheral neuropathy, which can be caused by various conditions such as diabetes mellitus 2, 3, 4.
- Trauma: Repetitive micro-trauma in a foot with impaired sensation can contribute to the development of Charcot joint 5.
- Neurovascular changes: Pathological innervation of the blood vessels can lead to neurovascular changes, which can play a role in the pathogenesis of Charcot joint 5.
- Mechanical factors: Mechanical stress and instability in the joint can contribute to the development of Charcot joint 5.
- Biological factors: Biological factors such as inflammation and bone resorption can also contribute to the development of Charcot joint 6, 5.
Pathophysiology
The pathophysiology of Charcot joint involves a combination of mechanical, vascular, and biological factors. The exact mechanisms are not fully understood, but it is thought that the loss of sensation and proprioception in the affected joint leads to repetitive micro-trauma, which can cause inflammation and damage to the joint 4, 5. The neurotrophic theory, which suggests that sympathetic denervation of the bone vasculature leads to bone resorption, has been largely discredited 6.
Associated Conditions
Charcot joint is often associated with conditions that cause peripheral neuropathy, such as:
Diagnosis and Classification
The diagnosis of Charcot joint can be challenging, and a combination of clinical evaluation, imaging studies, and laboratory tests is often necessary to confirm the diagnosis 2, 3, 4, 5. Various classification systems have been proposed to classify Charcot joint, including the Eichenholtz classification and the Sanders classification 5.