Evaluating the Effectiveness of Commercially Available Antiadhesion Tendon Protector Sheets in Tendon Repair Surgery Versus Tendon Repair Surgery Alone: A Preclinical Model Study.

PURPOSE: Adhesion formation is the major complication after tendon repairs that halts functional restoration and causes disability in patients. This study aimed to compare the antiadhesion efficacy of two tendon protector sheets using a previously established turkey flexor tendon model. METHODS: Twenty-four adult Bourbon Red turkeys were randomized into three groups: (1) control, (2) type I collagen-glycosaminoglycan (Collagen-GAG), and (3) hyaluronic acid. In each group, the flexor digitorum profundus tendon of the middle digit was sharply lacerated at the proximal interphalangeal joint level. All operated feet were immobilized until sacrifice 6 weeks after the surgery. After sacrifice, the repaired and normal digits were collected for biomechanical testing, adhesion scores, histological examination, and adhesion-related gene expression analysis. RESULTS: At 42 days after tendon repair, the normalized work of flexion of the repaired digit was the lowest in the Collagen-GAG group. The Collagen-GAG group also had the lowest gross adhesion score, indicating minimal adhesion. The hyaluronic acid group showed lower adhesion scores compared with the control, but the difference was not statistically significant. Microscopically, the Collagen-GAG group had a significantly lower histological adhesion score than the control group. In the Collagen-GAG group, the gene expression levels of WNT3A, WNT5A, and WNT7A were suppressed. CONCLUSIONS: In an avian model of flexor tendon repair, the application of tendon protector sheets reduces peritendinous fibrotic tissue formation histologically. CLINICAL RELEVANCE: There are currently limited commercially available products to reduce postoperative peritendinous adhesions. Further validation is needed to confirm the effectiveness of tendon protector sheets in improving surgical outcomes following tendon repairs.

Ultrasound Shear Wave Elastography for Noninvasive Diagnosis of Acute Compartment Syndrome Using a Novel In Vivo Turkey Model.

INTRODUCTION: Acute Compartment Syndrome (ACS) is a severe trauma caused by elevated intra-muscle-compartment pressure (ICP). The current standard method for diagnosis is to insert a needle into the muscle sterilely under anesthesia. However, to secure the environment is sometimes not easy and leads to delays in diagnosis. Recently, we have focused on shear wave ultrasound elastography (SWE) as an alternative, which can be done concisely in unclean environment and without anesthesia. We would like to report the usefulness of SWE for ACS diagnosis using 2-pedal walking turkey model recently developed in our lab. MATERIALS AND METHODS: A total of 32 1-year-old Bourbon turkeys were used. 5% solution of chicken albumin was infused continuously into the tibialis cranialis (TC) muscle using IV pump. The ICP was increased stepwise from 0 to 50 mmHg. During the rising of ICP, the correlation between values of SWE (kPa) and ICP (mmHg) was measured. After the ICP reached 50 mmHg, half of the turkeys were maintained at this pressure for 2 hours and the rest for 6 hours. After infusion, a fasciotomy was performed on the half turkey. Half of the turkeys were euthanized after 2 weeks and the rest after 6 weeks. SWE of TC muscle and walking gait data on turkeys using a portable walkway system were measured weekly until euthanasia. At euthanasia, isometric tetanic muscle force (ITF) tests to TC muscle and histological evaluations were performed. RESULTS: SWE value (kPa) was highly significantly correlated to the actual ICP (mmHg) (R2 = 0.91). Stance of ACS side leg were significantly extended, and swing of the control side shortened from the second to the third week after ACS in the 6 hours infusion-no-fasciotomy group (P < 0.05*). ITF was significantly reduced mainly in the 6 hours infusion group (P < 0.05*). Histological evaluation revealed that in the 6 hours infusion and 6 weeks survival group, both the muscle fiber and intercellular distances were significantly expanded (P < 0.05). CONCLUSION: SWE seems to be a substitute measure of ICP in diagnosing ACS. With regard to our in vivo ACS model using turkey, survival at 50 mmHg ICP for 6 hours and 6 weeks post ACS would be an appropriate situation.

Impact of High Fat Diet and Sex in a Rabbit Model of Carpal Tunnel Syndrome.

Carpal tunnel syndrome (CTS) is a common musculoskeletal disorder, characterized by fibrosis of the subsynovial connective tissue (SSCT) mediated by transforming growth factor beta (TGF-ß). Risk factors for CTS include metabolic dysfunction and age. Additionally, the incidence of CTS is higher in women. In this study we hypothesized that a high-fat diet (HFD), a common driver of metabolic dysfunction, would promote SSCT fibrosis found in CTS and that this response would be sex dependent. To test this, we examined the effects of HFD and sex on SSCT fibrosis using our established rabbit model of CTS. Forty-eight (24 male, 24 female) adult rabbits were divided into four groups including HFD or standard diet with and without CTS induction. SSCT was collected for histological and gene expression analysis. HFD promoted SSCT thickening and upregulated profibrotic genes, including TGF-ß. Fibrotic genes were differentially expressed in males and females. Interestingly while the prevalence of CTS is greater in women than in men, the converse is observed in the presence of metabolic dysfunction. This work recapitulates this clinical observation and begins to elucidate the sex-based differences found in SSCT fibrosis. This knowledge should drive further research and may lead to metabolic and sex specific therapeutic strategies for the treatment of patients with CTS.