# Tendon modification with percutaneous Ultrasound-Guided Tenotomy using TENEX®: A histological and macroscopic analysis of a bovine cadaveric model

## TL;DR

This study examines how a tendon treatment called PUTT affects bovine tendons, showing that longer treatment times cause more structural changes.

## Contribution

The study provides the first histological and macroscopic analysis of PUTT's effects on tendons using a bovine cadaveric model.

## Key findings

- Longer PUTT treatment durations caused greater separation of tendon structures like the paratenon and fascicles.
- Fascicle penetration depth increased significantly with treatment time, reaching up to 3.93 mm at 7 minutes.
- Statistical analysis confirmed significant differences in structural changes across treatment durations.

## Abstract

Chronic tendinopathy treatment remains elusive; however, percutaneous Ultrasound-Guided Tenotomy using TENEX® (PUTT) has demonstrated promising clinical outcomes, but the mechanism of action is not clearly defined. This study aims to describe potential mechanisms using an ex-vivo animal model. The objective of the study is to examine the histological effects of PUTT on the bovine soleus tendon across varying treatment durations.

Twelve bovine soleus tendons were allocated to four cohorts to undergo PUTT for 1, 3, 5, and 7 min. Each specimen was treated on one side, the opposite side serving as a control. Macroscopic and microscopic analyses were conducted to assess tendon sheath, fascicle, and perineural disruption. Fascicle penetration was measured using ImageJ software. Statistical analyses were performed using Analysis of Variance (ANOVA), with significance levels set at p < 0.05.

Macroscopic and microscopic examination revealed progressive separation of the paratenon, peritendinous nerves, and fascicles, correlating with increased treatment duration. Fascicle penetration depths were 0.1 mm, 2.57 mm, 2.61 mm, and 3.93 mm at 1, 3, 5, and 7 min, respectively. ANOVA confirmed significant differences among groups (F (3, 8) = 620.898, p < 0.001), with a large effect size (η2 = 0.996. Tukey's Honest Significant Difference (HSD) test revealed significant differences between most groups (p < 0.001), except between the 3-min and 5-min treatments, which showed no significant difference (p = 0.969).

PUTT induces significant structural changes in the paratenon and fascicle layer with longer treatment duration, resulting in more pronounced modifications.