A suture securing instrument can include a cylindrical body that has an inner circumferential surface, and a securing portion configured to secure a suture. The securing portion can include an outer circumferential surface supported by the inner circumferential surface of the cylindrical body by moving along a longitudinal axis relative to the cylindrical body, and a holding portion configured to hold the suture between the cylindrical body and the securing portion. The holding portion can also include a groove for the suture.