What are other causes of joint deformities besides typical inflammatory conditions, such as systemic lupus erythematosus (SLE), mixed connective tissue disease, or spondyloarthritis?

Other Causes of Joint Deformities Beyond Typical Inflammatory Conditions

Joint deformities can result from degenerative processes, metabolic bone disease, infectious complications, traumatic injuries, and non-inflammatory connective tissue disorders—not just the inflammatory conditions like SLE, mixed connective tissue disease, or spondyloarthritis.

Degenerative and Mechanical Causes

Spondylotic Changes and Spinal Degeneration

• Spinal degenerative changes, disc herniations, and malalignment can lead to significant structural deformities, particularly in the cervical and thoracic spine 1
• These degenerative processes may be accentuated in patients with congenitally short pedicles 1
• Spinal fractures represent a critical non-inflammatory cause of deformity that must be considered, especially in patients with disease course changes 1
• Fractures are more prevalent than often expected and may occur with or without neurological symptoms, even without preceding trauma 1

Osteoporotic Deformities

• Osteoporotic compression fractures are common in the thoracic spine and represent a major cause of spinal deformity 1
• Early imaging should be considered in patients >65 years of age or those with chronic steroid use 1

Infectious Etiologies

Epidural and Soft Tissue Infections

• Epidural abscesses or hematomas can cause extrinsic compression leading to deformity 1
• In postoperative patients, seromas, pseudomeningoceles, hematomas, and epidural abscesses can develop and cause structural changes 1

Infectious Arthritis

• Septic arthritis presents with acute onset, severe pain, marked inflammation, and erythema 2
• While typically monoarticular, polyarticular involvement can occur in immunocompromised patients or intravenous drug users 2
• Requires emergency treatment with antibiotics and often surgical drainage 2

Vascular and Ischemic Causes

Spinal Cord Ischemia

• Atheromatous disease or complications of aortic surgery are the most common causes of spinal cord ischemia in adults 1
• Other predisposing factors include systemic hypotension, thoracoabdominal aneurysms or dissection, sickle cell disease, and spinal arteriovenous malformations 1
• Fibrocartilaginous embolic disease can rarely cause acute ischemic myelopathy 1

Neoplastic Causes

Primary and Metastatic Tumors

• Primary or metastatic tumors of the extradural and intradural extramedullary spaces can cause extrinsic compression of the spinal cord, resulting in progressive deformity 1
• These should be considered in patients with progressive symptoms or red flags 1

Other Systemic Inflammatory Conditions

Behçet Disease

• Behçet disease is a small vessel vasculitis associated with HLA-B51 that can involve arteries and veins 1
• Vascular involvement occurs in one-third of patients and may result in aneurysm formation and structural complications 1
• Systemic corticosteroids are typical therapy for vascular involvement 1

Relapsing Polychondritis

• Relapsing polychondritis causes recurrent inflammation and widespread destruction of cartilage and connective tissues 1
• Respiratory tract involvement affects >50% of patients, with chondritis affecting larynx, trachea, and bronchi 1
• Can lead to structural deformities through cartilaginous fragmentation and destruction with replacement by fibrosis 1

Sjögren Syndrome and Sarcoidosis

• Sjögren syndrome and sarcoidosis are systemic inflammatory conditions that can result in joint and structural involvement 1
• These conditions may cause inflammatory changes leading to deformities independent of typical rheumatoid or lupus patterns 1

Non-Erosive Deforming Arthropathies

Jaccoud's Arthropathy

• Jaccoud's arthropathy can occur in SLE and other conditions, characterized by severe deformities (ulnar deviation, swan neck, Z-thumb) that are initially passively correctable 3, 4
• Results from longstanding arthritis rather than erosive disease 5
• May progress to fixed deformities in severe cases, compromising functional capacity 3
• High-resolution ultrasound reveals high prevalence of tenosynovitis and synovial changes even without erosions 6

Clinical Pitfalls to Avoid

• Do not assume all deformities in patients with known inflammatory disease are due to that condition—spinal fractures, infections, and tumors must be excluded when there is a significant change in disease course 1
• Obtain appropriate imaging (MRI and/or CT) when suspecting non-inflammatory causes, particularly in patients not responding to pharmacological treatment 1
• Consider age-related and medication-related risk factors for osteoporotic fractures, especially in patients on chronic corticosteroids 1
• Recognize that vascular causes like spinal cord ischemia can present acutely and require specific imaging protocols including diffusion-weighted imaging 1