Difference between an osteophyte a syndesmophyte and an enthesophyte?
Osteophytes are thick, triangle-shaped osseous excrescences that form at the site of Sharpey fibers attachment between the annulus fibrosus and the margin of the vertebral body just above or below the endplate margin.
- An osteophyte may eventually grow and meet an osteophyte on the other side of the disc space to form a bridging osteophyte.
- Osteophytes can contribute both to the functional properties of affected joints and to clinical relevant symptoms.
- Osteophyte formation is highly associated with cartilage damage but osteophytes can develop without explicit cartilage damage.
- Osteophytes are mainly derived from precursor cells in the periosteum and growth factors of the TGFbeta superfamily appear to play a crucial role in their induction.
Osteophyte is one of the salient features of osteoarthritis
Osteophytes typically begin by growing outward.
What are the risk factors of osteophytes?
The below are the risk factors for development of osteophytes
- Physical activity
- body mass index
- Certain genetic
- Environmental factors
Syndesmophytes are outgrowths from the bone (osseous excrescences) from the spinal ligaments as they attach to adjacent vertebral bodies.
Syndesmophytes are typically associated with ankylosing spondylitis.
Ankylosing spondylitis (AS) is characterized by the formation of syndesmophytes and occurs more frequently in HLA-B27+ individuals, but whether these two phenomena are related has been uncertain.
According to the results of a new study, HLA-B27 misfolding is directly linked to syndesmophyte formation via tissue-nonspecific alkaline phosphatase (TNAP), in a process that can be targeted therapeutically.
Syndesmophytes are thin, gracile ossifications of the annulus fibrosus and are more vertically oriented than osteophytes, attaching right at the endplate margin.
Syndesmophytes are seen in only a limited number of conditions including:
- ankylosing spondylitis
- reactive arthritis
- psoriatic arthritis
Appearances of the Syndesmophytes in various diseases or conditions
- In Reiter’s syndrome and psoriasis – Syndesmophytes typically appear as non-marginal syndesmophytes. They are massive and bridge adjacent vertebrae asymmetrically. Usually in these conditions they appear to arise from a broad zone on the vertebrae, and tend to spare the anterior surfaces of the vertebrae.
- In ankylosing spondylitis – Syndesmophytes typically appear as marginal syndesmophytes. They tend to be thinner, more vertical, and symmetrical, involving anterior as well as the lateral vertebral body margins. The disc space is often narrowed, and vertebral bodies may show anterior end plate erosions and appear to lose the normal anterior concavity
In this study, mesenchymal stem cells (MSCs) were derived from the entheses of patients with AS to address if there is any abnormality in AS-derived MSCs,” explains co-corresponding author Kuo-I Lin. “No significant differences were found in the production of the cytokines or chemokines that we tested in AS-derived MSCs as compared with control MSCs, but AS-derived MSCs did show accelerated mineralization upon osteogenic induction.
Enthesophytes are bony projections that develop at sites of tendon or ligament attachment to bone.
Enthesophyte formation is new bone at the site of attachment of a tendon, ligament, or joint capsule to bone. Entheseous new bone reflects the bone’s response to stress applied through these structures, such as ligamentous tearing or capsular traction.
Like osteophytes, enthesophyte formations take several weeks to months to develop and may or may not be associated with clinical signs.
Knowledge of ligament, tendon, and capsular insertions is essential to determine which soft tissue structure may have been damaged. In some locations, such as the hock, differentiation between enthesophyte and osteophyte formation is not easy.
The attachments of the cranialis tibialis, fibularis tertius, and dorsal tarsal ligament are close to the joint margins of the tarsometatarsal joint, and differentiation between entheseous new bone at these attachments and periarticular osteophyte formation may be difficult.
Fracture of an enthesophyte and mineralization within the tendon or ligament attachment also may occur.
A relatively common site is the radial tuberosity at the attachment of biceps brachii.
Small linear opacities may be seen dorsal to the summits of the spinous processes in the thoracic region, which are associated with tearing of the attachment of the supraspinous ligament.
What research says about Osteophytes and Enthesophytes?
In a study, 226 radiographs from HBM cases and 437 radiographs from control subjects were included.
Enthesophytes (grade ≥1) and moderate enthesophytes (grade ≥2) were more prevalent in HBM cases compared with controls (adjusted odds ratio [OR] 3.00 [95% confidence interval (95% CI) 1.96–4.58], P < 0.001 for any enthesophyte; adjusted OR 4.33 [95% CI 2.67–7.02], P < 0.001 for moderate enthesophytes).
In the combined population of cases and controls, the enthesophyte grade was positively associated with BMD at both the total hip and lumbar spine (adjusted P for trend < 0.001).
In addition, a positive association between osteophytes and enthesophytes was observed; for each unit increase in enthesophyte grade, the odds of any osteophyte being present were increased >2-fold (P < 0.001).