What causes olecranon bone spurs?

What Causes Olecranon Bone Spurs

Olecranon bone spurs (traction spurs) form primarily from repetitive mechanical stress and traction forces at the triceps tendon insertion on the olecranon process, commonly associated with inflammatory conditions and chronic overuse.

Primary Mechanisms of Formation

Repetitive Mechanical Stress and Traction Forces

• Olecranon spurs develop in the superficial fibers of the distal triceps tendon at its insertion point on the olecranon, representing an enthesophyte (bone formation at tendon attachment sites) 1.
• The spur formation occurs at the site where the triceps tendon inserts on the olecranon, corresponding directly to this anatomical attachment point 2.
• Repetitive submaximal stress on the bone leads to accelerated bone remodeling, where osteoclastic activity initially exceeds osteoblastic new bone formation, eventually resulting in reactive bone formation as the body attempts to reinforce the stressed area 3.

Athletic and Occupational Overuse

• Specific athletic activities predispose to olecranon process fractures and spur formation, particularly in javelin throwers and baseball pitchers who subject the posterior elbow to repetitive high-force extension movements 3.
• Fatigue fractures can develop in the olecranon from repetitive submaximal stress on otherwise normal bone in athletes 3.

Associated Inflammatory Conditions

Chronic Inflammatory States

• Olecranon spurs are commonly found as an underlying clinical problem in patients with inflammatory conditions including triceps tendonitis, olecranon bursitis, and gout 4.
• In a radiographic study comparing affected elbows with controls, olecranon spurs, amorphous calcium deposits, or both were present in 57% of patients with traumatic olecranon bursitis compared to only 14% of controls (p < 0.01) 2.
• The pathologic lesion in chronic cases can include synovial frond proliferation that invades the tendon substance, suggesting ongoing inflammatory processes contribute to spur formation 5.

Bursal Pathology

• Chronic olecranon bursitis creates a mechanical and inflammatory environment that promotes spur development 4.
• Nodules in the bursal floor are frequently noted in patients with chronic bursitis, and the bursa may become partially septated, indicating chronic inflammatory changes 2.

Anatomical Vulnerability

Poor Soft Tissue Protection

• The olecranon's superficial location with poor soft tissue and muscle protection makes it particularly liable to injury following direct impact, which can initiate the cascade leading to spur formation 6.
• The triceps muscle pull on the olecranon tip creates constant traction forces that, over time, stimulate reactive bone formation 6.

Clinical Pitfalls and Caveats

• Radiographs are recommended as the initial imaging modality to identify olecranon spurs and exclude fractures or other bony abnormalities 7, 8.
• Not all olecranon spurs are symptomatic; the presence of a spur on imaging does not automatically indicate it is the source of pain 1.
• Patients with chronic olecranon bursa problems should be carefully examined for triceps function, as the inflammatory process can weaken the tendon insertion where spurs form 5.
• Recurrent spur formation can occur even after surgical excision, with at least one study reporting recurrence requiring repeat surgery 1.