A partial reverse shoulder prosthesis comprising: a humeral stem; and, a variable angle tray adapted to be coupled to the humeral stem, the variable angle tray comprising a plate including a through hole at least partially defined by a wall that at least partially defines an internal cavity, characterised in that the variable angle tray further comprises a variable angle stem occupying at least a portion of the internal cavity, the variable angle stem selectively axially repostionable with respect to the plate to change the axial position of the variable angle stem with respect to the plate, the variable angle stem comprising: a first washer including threads at least partially defining a first opening and being insertable into the internal cavity; a post at least partially occupying the internal cavity, the post including a tapered crown and an appendage axially extending from the plate, where the appendage is sized to be received the humeral stem via a friction fit, and, a pin including a threaded head and a longitudinal shaft extending from the threaded head, the pin is insertable into the first opening, where the threaded head is sized to engage the threads of at least one of the first washer and the post; wherein the wall is sized to retain the first washer and at least a portion of the post within the through hole. a humeral stem; and, a variable angle tray adapted to be coupled to the humeral stem, the variable angle tray comprising a plate including a through hole at least partially defined by a wall that at least partially defines an internal cavity, characterised in that the variable angle tray further comprises a variable angle stem occupying at least a portion of the internal cavity, the variable angle stem selectively axially repostionable with respect to the plate to change the axial position of the variable angle stem with respect to the plate, the variable angle stem comprising: a first washer including threads at least partially defining a first opening and being insertable into the internal cavity; a post at least partially occupying the internal cavity, the post including a tapered crown and an appendage axially extending from the plate, where the appendage is sized to be received the humeral stem via a friction fit, and, a pin including a threaded head and a longitudinal shaft extending from the threaded head, the pin is insertable into the first opening, where the threaded head is sized to engage the threads of at least one of the first washer and the post; a first washer including threads at least partially defining a first opening and being insertable into the internal cavity; a post at least partially occupying the internal cavity, the post including a tapered crown and an appendage axially extending from the plate, where the appendage is sized to be received the humeral stem via a friction fit, and, a pin including a threaded head and a longitudinal shaft extending from the threaded head, the pin is insertable into the first opening, where the threaded head is sized to engage the threads of at least one of the first washer and the post; wherein the wall is sized to retain the first washer and at least a portion of the post within the through hole.