Which type of arthritis most commonly causes new bone formation at joint margins?

Osteoarthritis Causes New Bone Formation at Joint Margins

Osteoarthritis is the form of arthritis that causes bones to grow at joints, specifically through the formation of osteophytes (bone spurs) at joint margins and subchondral bone remodeling. 1, 2

Mechanism of Bone Growth in Osteoarthritis

Osteoarthritis involves active bone remodeling processes that result in new bone formation at multiple sites:

• Osteophyte formation occurs at the joint margins as a characteristic feature of OA, representing actual new bone tissue growth 3, 4
• Subchondral bone changes include increased bone turnover, altered mineralization, and volume changes that thicken the bone beneath the cartilage 5
• The entire joint undergoes simultaneous pathological changes including cartilage degradation, bone remodeling, osteophyte formation, and synovial inflammation 6

Distinguishing from Other Arthritides

While psoriatic arthritis can also cause new bone formation, it presents differently:

• Psoriatic arthritis causes "juxta-articular new bone formation" at entheses (tendon/ligament attachment sites) rather than at joint margins 1
• This entheseal bone proliferation in psoriatic arthritis represents a response to chronic mechanical stress and inflammation at attachment points, not the marginal osteophytes seen in OA 7
• Psoriatic arthritis also features osteolysis (bone destruction) alongside new bone formation, creating a mixed picture 1

Clinical Significance

The bone changes in osteoarthritis have important clinical implications:

• Radiographic diagnosis relies heavily on identifying marginal osteophytes and joint space narrowing as hallmark features 2
• Osteophytes can artificially elevate bone mineral density measurements on DXA scans, potentially masking concurrent osteoporosis 8
• The relationship between osteophytes and pain remains conflicting in research, though subchondral bone changes like bone marrow lesions correlate more consistently with symptoms 5

Prevalence and Impact

Osteoarthritis is by far the most common arthritis causing bone growth:

• OA affects more than 240 million people worldwide and is the most frequent reason for activity limitation in adults 2
• Approximately 40% of women aged 55 and 85% of those over 75 years have spine osteoarthritis with associated osteophyte formation 8
• The disease prevalence after age 65 reaches about 60% in men and 70% in women 3