Rotator cuff tears (RCT) are one of the most prevalent conditions affecting the adult shoulder, occurring in an estimated 9%–39 % of the adult population [1]. In the United Sates, approximately 17 million individuals are affected with RCTs [2], and the prevalence significantly increases with age [3]. Repair or reconstructive surgery is selected when conservative treatment is unsuccessful and more than 250,000 surgeries have been performed in the USA, and the number is increasing year by year [4]. The surgical procedure is generally to repair the torn rotator cuff (RC) stump to the tuberosity for primary repair. In the case of irreparable massive RCT, tendon transfer or reconstruction using artificial or biological grafts has been performed [[5], [6], [7]].

The development of medical materials and devices in the field of tissue engineering and regenerative medicine (TERM) is essential to improve surgical outcomes in orthopedic surgery, and large animal experiments have long been performed in vivo research [[8], [9], [10], [11]]. In recent years, there has been a surge in the use of porcine models for large animal studies in orthopedic disease [12]. In the United States, over the past 15 years, pigs have been more frequently used in animal experimentation than have sheep or dogs [13]. Particularly, there is an increasing number of reports about models of cartilage injury, ligament injury and meniscal tear that simulate clinical knee joint disease [[14], [15], [16], [17], [18], [19]]. However, in basic research on RC disease, sheep or goat are mostly used as a RCT model in large animal experiments, and there have been no reports using pigs [[20], [21], [22], [23], [24], [25], [26]]. If pigs can be used as preclinical models for shoulder joint surgery, the animal model may potentially be extended to other research fields and animal species, while adhering to ethical principles of animal welfare [16].

We hypothesized that the porcine shoulder joint exhibits a similar structure to the human RC and could be used for in vivo studies of RCTs. The primary objective of this study was to morphologically and histologically evaluate the RC attachment of the porcine humeral head. The second is to perform a histological evaluation of the acute RCT/RCR model.