No, Bursitis is Not a Joint Deformity
Bursitis is a periarticular inflammatory condition affecting the bursa (a fluid-filled sac that cushions tissues around joints), not a structural joint deformity. It is classified as a soft tissue lesion distinct from joint pathology.
What Bursitis Actually Is
- Bursitis is inflammation of the bursa, which are fluid-filled sacs located between tendons, muscles, and bony prominences that provide cushioning 1, 2.
- It is categorized as a periarticular lesion (around the joint, not within it), alongside conditions like tendinitis and tenosynovitis 3.
- The condition results from trauma, chronic overuse, or inflammation, and may be associated with underlying intra-articular processes but is not itself a joint abnormality 2.
How Bursitis Differs from Joint Deformity
Bursitis is a Soft Tissue Problem
- Clinical assessment guidelines specifically distinguish bursitis from arthropathy (joint inflammation/damage) 3.
- Rheumatology training emphasizes identifying "common periarticular lesions (bursitis, tendinitis, tenosynovitis, enthesopathy)" as separate from joint pathology 3.
Joint Deformities are Structural Changes
- True joint deformities include articular dislocation, erosions, osteophytes, and changes in bone profile 3.
- These represent permanent structural alterations to the joint architecture itself, whereas bursitis involves reversible inflammation of surrounding structures 3.
Clinical Implications
- Bursitis can be detected on ultrasound as bursal fluid collections, thickening, and inflammation separate from the joint space 3, 4.
- Examples include trochanteric bursitis, iliopectineal bursitis, and prepatellar bursitis, all of which are periarticular conditions 3, 1.
- While chronic bursitis may show calcifications or soft tissue swelling on imaging, these are not joint deformities 4.
Important Caveat
- Bursitis can coexist with joint deformities (such as in degenerative arthritis with varus/valgus knee deformities and concurrent anserina bursitis), but the two conditions remain distinct entities 5.
- In patients with joint prostheses, extracapsular bursal disease could be misinterpreted, so careful differentiation is essential 6.