Disclosures: Lauren N. Neuman, DO, MBA: No financial relationships or conflicts of interest

Objective : To investigate the cellular and tissue-level effects of percutaneous ultrasound tenotomy (PUT) on chronic tendinopathy.

Design: Randomized, within-subject controlled design. Kartogenin (KGN) beads were implanted in the bilateral Achilles tendons of male New Zealand white rabbits to model chronic tendinopathy and six weeks later, one randomly selected Achilles’ tendon in each rabbit underwent PUT. Six weeks following PUT, the bilateral Achilles’ tendons were sectioned to determine the histological effects of PUT.

Setting : n/a

Participants : 10 skeletally mature, male New Zealand white rabbits

Interventions: Under anesthesia, a kartogenin (KGN) bead was implanted in each Achilles’ tendon to stimulate endogenous stem/progenitor cells to differentiate into chondrocytes. Following KGN bead placement, all rabbits returned to free cage activity for six weeks. Animals were then anesthetized, and one randomly selected Achilles’ tendon of each rabbit was treated with PUT (TX-1 instrument; Tenex Health: Lake Forest, CA) under sonographic guidance using 1 minute of ultrasound energy. Following unilateral PUT, all rabbits returned to free cage activity for 6 weeks. Tendons were then harvested.

Main Outcome Measures: Hematoxylin and eosin (H&E) stains were used to evaluate structural changes. Alcian blue staining was utilized to identify cartilage cells/matrices. Bonar scoring was used for quantification of structural changes including cell morphology, collagen, cellularity, vascularity, calcification, ground substance and fatty change.

Results: In paired, non-parametric analyses, the median (IQR) difference in total Bonar scores between treated and untreated tendons was 1 (0, 2) (p=.125). There were no statistically significant differences detected in sub-scores for collagen arrangement, cellularity, vascularity, calcification, ground substance deposition (all p>0.2). Currently, the results of immunohistochemical analyses are pending.

Conclusions: Differences in tissue characteristics between the paired treated and untreated tendons were not detected to date. Analyses are ongoing. Although over 100,000 PUT treatments have been completed for patients with chronic tendinopathy, better understanding of the tissue-level effects could enable more tailored treatment for chronic tendinopathy.

Level of Evidence: Level II

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/advancing-physiatric-care-of-tendinopathy-through-controlled-study-of-healing-following-percutaneous-ultrasound-tenotomy/