Distinct topography of erosion and new bone formation in achilles tendon enthesitis: Implications for understanding the link between inflammation and bone formation in spondylarthritis

Abstract

Objective. This study combined ultrasonography of the Achilles tendon enthesis at different stages of spondylarthritis (SpA) with microanatomic studies of normal cadaveric entheses, with the aim of exploring the relationship between bone erosion and new bone formation in enthesitis.Methods. Thirty-seven patients with SpA and Achilles tendon enthesitis (20 with early SpA and 17 with chronic SpA) and 10 normal control subjects underwent ultrasound scanning. The presence of bone erosion and spur formation was recorded at 3 sites: the proximal and distal halves of the enthesis and the adjacent calcaneal superior tuberosity. Parallel histologic analysis was performed on cadaveric Achilles tendon entheses to determine whether regional variations in bone density and trabecular architecture in relation to fibrocartilage distribution are related to disease patterns.Results. Bone erosion in patients with early SpA occurred at either the proximal insertion or the superior tuberosity (11 of 20 patients; P < 0.001 versus distal enthesis). Very small spurs, which were present almost exclusively at the distal enthesis, were evident in patients with early SpA and in normal control subjects. However, large spurs were evident distally only in patients with chronic SpA (9 of 17 patients, compared with none of 20 patients with early SpA; P < 0.0001). Histologic studies showed that aged normal individuals had small spurs at the corresponding location. The bone-to-marrow ratio was also significantly lower in the regions prone to erosions (P < 0.05).Conclusion. Bone erosion in association with Achilles tendon enthesitis in SpA is anatomically uncoupled from bone formation-the 2 processes are topographically and temporally distinct. We thus conclude that disease patterns in SpA are related to normal enthesis structure and biomechanics.

Ultrasonography and Low-field Magnetic Resonance Imaging of the Common Calcanean Tendon in a Rabbit Model for Tendinopathy Research: a Descriptive Study of Normal Anatomy

“…The transition of muscle bellies to tendons was clear and evident. Insertional Achilles tendinopathy is associated with enthesophyte formation, bone erosion and calcification of the tendon at insertion site (McGonagle et al 2008, Pierre-Jerome et al 2010, van Dijk et al 2011. In our rabbit model, magnetic resonance provided more detailed images of the region of the calcaneal insertion than sonography.…”

“…This protocol was determined not only based on significant contribution of these tendons to the common calcanean tendon but also according to their applicability in tendinopathy research in a rabbit model (Young et al 1998, Oryan et al 2012. Sonograms and scans were assessed qualitatively with a description of normal appearance of elements analogical to those assessed in human Achilles tendon pathologies, that means echogenicity or signal intensity (depending on imaging technique) of the tendon, musculotendinous junctions, the region of calcaneal insertion, the paratenon, the pre-Achilles fat pad and the bursa of calcaneal tendon (Kamel et al 2003, Bleakney and White 2005, Harris and Peduto 2006, Leung and Griffith 2008, McGonagle et al 2008, Pierre-Jerome et al 2010, van Dijk et al 2011, Del Buono et al 2013). Morphometry of the common calcanean tendon was performed on longitudinal sonograms and sagittal T1-weighted MRI (magnetic resonance imaging) scans presenting median section of the crus.…”

Concepts in monitoring enthesitis in patients with spondylarthritis- the role of musculoskeletal ultrasound

“…Fewer studies demonstrated the criterion valid-ity and construct validity [3,4,[23][24][25]34,38,47,51,[57][58][59][60][61][62][63][64][65][66][67][68][69][70] where comparators were clinical examination, MRI, XRay, and histology. The lack of information is partially explained because of the difficulties in finding the best comparator, the relatively new use of ultrasound in SpA, and a slow rate of disease progression [5,71,72].…”

Ultrasound assessment of elbow enthesitis in patients with seronegative arthropathies

“…Bone erosions were found to occur early in the elbow region of our patients, whereas in tennis elbow, bone erosion is rarely encountered. This might be a differentiating feature since seronegative arthropathy displays special predilections for the bony attachment, as in sacroiliac joint involvement [4,[15][16][17]. Ultrasound depicted early bone erosion-like changes in patients with enthesitis as decortication defects, a few millimeters in length, at the points of synovial attachment.…”