What causes a wrist bone spur in a middle-aged or elderly individual with a history of wrist injuries or underlying conditions such as osteoarthritis (OA) or rheumatoid arthritis (RA)?

Causes of Wrist Bone Spurs

Wrist bone spurs (osteophytes) develop primarily from post-traumatic osteoarthritis following wrist injuries, chronic instability from ligamentous disruption, or inflammatory arthropathies—with the vast majority (95%) occurring in the periscaphoid region due to abnormal joint loading and repetitive microtrauma. 1, 2, 3, 4

Primary Mechanisms

Post-Traumatic Osteoarthritis (Most Common)

• Scaphoid-related pathology accounts for approximately 95% of wrist osteoarthritis cases, manifesting as SLAC (scapholunate advanced collapse) wrist in 55% of cases, triscaphe arthritis in 26%, or a combination in 14% 4
• Nonunited or malunited scaphoid fractures create abnormal joint loading that triggers osteophyte formation as the body attempts to stabilize the joint 3
• Distal radius fractures, particularly when residual articular surface step-off exceeds 2 mm, lead to long-term osteoarthritis development 5
• The degenerative sequence begins with articular alignment problems between the scaphoid and radius, then progresses to involve the capitate-lunate articulation secondary to carpal collapse 4

Ligamentous Disruption and Instability

• Disruption of intercarpal, radiocarpal, radioulnar, or ulnocarpal ligaments produces asymmetric load distribution across wrist joints 3
• Chronic instability leads to repetitive microtrauma, which accelerates cartilage destruction and adjacent bone remodeling with osteophyte formation at joint edges 2
• Early detection and treatment of instability is essential, as rapid disease progression occurs once the wrist becomes unstable 2

Inflammatory and Metabolic Arthropathies

• Rheumatoid arthritis primarily targets the wrist along with MCPJs and PIPJs, causing inflammatory destruction that can lead to secondary osteophyte formation 5, 6
• Gout frequently affects wrist joints and can superimpose on pre-existing osteoarthritis, complicating the clinical picture 5, 7
• Metabolic diseases like haemochromatosis mainly target MCPJs and wrists, similar to gout 7, 6
• Erosive osteoarthritis shows radiographic subchondral erosion with abrupt onset, marked pain, inflammatory symptoms (stiffness, soft tissue swelling, erythema), and mildly elevated CRP levels 5, 6

Pathophysiology of Bone Spur Formation

• Osteoarthritis leads to destruction of articular cartilage and adjacent bone, with compensatory osteophyte formation at the edges of afflicted joint surfaces 2
• Abnormal joint loading from any cause produces a spectrum of symptoms as involved joints degenerate, with the body forming bone spurs as a stabilization response 3
• The radiocarpal joint is typically involved early in disease progression, whereas the mediocarpal joint is affected at a later stage 8

Risk Factors

• Prior wrist injury is the dominant risk factor for post-traumatic wrist osteoarthritis 5, 1
• Increasing age over 40, female sex, and menopausal status increase risk for primary osteoarthritis 5
• Occupation or recreation-related repetitive wrist usage contributes to microtrauma accumulation 5
• Avascular necrosis of the carpus or developmental abnormalities can predispose to secondary osteoarthritis 3

Clinical Pitfalls

• Most wrist osteoarthritis is secondary rather than idiopathic—only a small minority of cases occur without identifiable cause 1
• The presence of bone spurs on imaging does not necessarily correlate with symptoms, as there is high prevalence of degenerative changes in asymptomatic individuals 8
• Meticulous clinical and radiographic evaluation is required to identify the specific pain-generating articulation(s), as treatment must target the correct joint 3
• Carpal boss (a specific bony prominence) can be detected on MRI and represents a distinct entity from generalized osteophyte formation 5