gms | German Medical Science

Introduction: Tendons are dense, highly organized, and relatively avascular tissues; however, tendon structural integrity and vascularity decline with age and may be associated with an increased risk of injury with aging. Furthermore, tendon vascularity may change in the presence of tendon pathology associated with acute inflammatory and healing processes, such as in response to rotator cuff tears. The purpose of this study is to evaluate the microvasculature of the supraspinatus tendon (SSP) and long head of the biceps tendon (LHBT) using a superficial microvascular imaging (SMI) ultrasound technique in asymptomatic, torn, and repaired rotator cuff tendons.

Methods: This study included 18 subjects with asymptomatic shoulders (55 ± 18 years, BMI 22.6 ± 3.0 kg/m², 7 males), 6 with an unrepaired RCT’s involving the SSP (64 ± 3 years, BMI 24. 6 ± 4.1 kg/m², 5 males, mean 28 months since tear), and 6 who had undergone rotator cuff repair and biceps tenodesis at least 4 months prior (57 ± 10 y, BMI 25.5 ± 1.5 kg/m², 5 males, mean 7 months since repair). An ultrasound examination was performed measuring the microvasculature in the SSP and proximal LHBT with the SMI mode. The area of the vascular signal (cm²) within the tendons was recorded in both transverse and longitudinal directions. Correlations between tendon vascular signal and age were assessed in asymptomatic subjects.

Results: There was significantly greater vascular signal in the longitudinal direction of torn supraspinatus (p = 0.036) and biceps tendons (p = 0.002) compared to asymptomatic and post-operative tendons. There were no differences between groups when vascularity was measured in the transverse direction (SSP p = 0.728, biceps p = 0.264). Correlations could not be found between the age of asymptomatic participants and the vascular signal within the SSP (p = 0.5063) and LHBT (p = 0.1566) in the longitudinal direction, nor in the transverse direction for the SSP (p = 0.2583) or LHBT (p = 0.3335).

Discussion: There was minimal vascular signal within asymptomatic tendons. The vascularity signal increased in individuals with unrepaired SSP tears. Approximately 4–8 months following SSP repair and biceps tenodesis, tendon vascularity was not significantly different from asymptomatic tendons. Overall, results suggest that ultrasound techniques that evaluate tendon microvasculature in the absence of contrast agents may represent a low-risk and reliable method to monitor rotator cuff tendons following injury and during recovery. Further investigation will examine if the increased vascularity in the torn state could be a potential target for medication to increase healing rates.