Intratendinous Pressure in the Rotator Cuff Tendons: A Cadaver Study

Background: Understanding intratendinous pressure within the rotator cuff tendons would help elucidate the biomechanics and pathogenesis of rotator cuff tendon disorders.This study directly measured and compared the intratendinous pressure in the supraspinatus (SST), subscapularis (SCT), and infraspinatus (IST) tendons in cadaveric specimens.Methods: Two fresh, unembalmed human cadavers (Cadaver 1: 72-year-old male; Cadaver 2: 65-year-old female) were examined.A 22-gauge needle was inserted into the central portion of each tendon (SST, SCT, and IST) under ultrasound guidance.Intratendinous pressure was measured in real time using a pressure manometry system during controlled normal saline infusion under real-time monitoring. Results:The highest intratendinous pressure was observed in the SST across all shoulders evaluated (56.8, 46.0, and 40.0 psi for the right shoulder of Cadaver 1, left shoulder of Cadaver 1, and right shoulder of Cadaver 2, respectively).In 2 of 3 shoulders, the SCT exhibited the second highest pressure, while the IST had the lowest pressure.In 1 remaining shoulder, the IST had the second highest pressure, and the SCT had the lowest pressure.Conclusions: Intratendinous pressure varies between rotator cuff tendons, with the SST exhibiting the highest pressure.Understanding these pressure differences provides valuable insights into the pathogenesis of rotator cuff tendinopathy and injury.