Application of poly(L, L-lactide-co-ε-caprolactone) copolymer medical implants to the treatment of massive rotator cuff tears in orthopedic shoulder surgery

Massive rotator cuff tears (MRCTs) remain a challenge in orthopedic shoulder surgery. The medical implant is a feasible and effective treatment option for MRCTs. However, the complications of implant migration usually occurred in clinical trials. To address this problem, biodegradable implants from poly(L, L-lactide-co-ε-caprolactone) (PLCL) copolymers were applied to treat MRCTs and presented major clinical effects in this study. The medical implants were designed in a dented shape to clad the head of the humerus, which could prevent the migration of implants and effectively improve shoulder function in a human specimen test. The structure was tested through finite element analysis and human specimen experimentation. The appropriate ratio of PLCL constituents was confirmed by examining the degradation of PLCL implants and measuring their mechanical, physical, chemical, and biological features. Samples were characterized using a scanning electron microscope, gel permeation chromatography, mechanical test, and transmission electron microscope. It was found that PLCL5050 (segment ratio PLA:PCL = 50:50) copolymer implants possess good processability and mechanical properties, as well as an appropriate degradation time of 177 days, which could satisfy the treatment requirements of MRCTs.