Abstract
Objectives:
Commercial compression sleeves have been promoted to ameliorate pain secondary to arthritis and tendinopathy. The fabric of one particular sleeve is embedded with nano-semiconductor fibers that reflect thermal energy produced by the body at a photonic wavelength mimicking low-level laser therapy. The device is theorized to accelerate the inflammatory stage of tissue healing to reach the proliferation and remodeling stages at faster rates. Previous clinical studies have shown a significant improvement in patient-reported outcomes between patients who did and did not use this sleeve to treat osteoarthritis. The objective of this investigation was to determine if compression sleeves embedded with nano-semiconductor fibers can accelerate Achilles tendon healing in a rabbit model.
Methods:
Twelve New Zealand White rabbits—under IACUC approval—were administered intratendinous injections of 0.2% collagenase into the right Achilles tendon to simulate an acute tendon injury. Rabbits were divided into three groups: group I received the commercial compression sleeve without nano-semiconductors (n = 4), group II received the sleeve with nano-semiconductors (n = 4), and group III received an alternate sleeve design also with nano-semiconductors (n = 4). Calf circumference measurements and thermal radiation imaging of the right lower leg of each rabbit were collected days 7, 14, 21, and 28 post-injection. Two rabbits from each group were sacrificed at the 14-day and 28-day marks and the right Achilles tendons were harvested. Histological analysis using picrosirius red staining was performed to evaluate tissue organization. A custom MATLAB program (MathWorks, Natick, MA) was used to quantify the collagen fiber dispersion within the Achilles tendon samples.
Results:
A statistically significant difference in calf circumference was found at the 28-day mark between group I versus groups II and III: group I had an average calf circumference of 5.2 cm while groups II and III had an average calf circumference of 4.85 cm (p = 0.036) and 4.60 cm (p = 0.021) respectively. Additionally, after 28 days, group I demonstrated an average pixel density intensity on thermal radiation imaging of 1,531,192 while groups II and III yielded average pixel density intensities of 1,363,515 (p = 0.008) and 1,335,456 (p = 0.003) respectively. Histological staining showed observable alterations in collagen architecture, with group I displaying widespread disorganization and degradation of type I and type III collagen fibers near the injection site. Groups II and III displayed greater organization at the 28-day mark in comparison to group I, with signs of tissue proliferation and remodeling evident. No statistically significant differences were found between group I versus groups II and III regarding collagen fiber dispersion at both the 2-week mark (p = 0.145, p = 0.236) and the 4-week mark (p = 0.113, p = 0.268), respectively.
Conclusions:
The nano-semiconductor fibers embedded within a commercial sleeve significantly decreased swelling and temperature of the lower leg 28 days following acute Achilles tendon injury in a rabbit model. Furthermore, histologic analysis demonstrated greater collagen fiber and extracellular matrix organization as well as greater proliferation of type III collagen suggesting a faster transition to the proliferation stage of tissue healing.
