Which type of suture material is known for its tendency to come untied?

Monofilament suture material is known for its smooth, single-strand nature, which can lead to a tendency to slip or come untied more easily than other types of sutures. This characteristic is due to the lack of friction between the suture and the tissue it is anchored in, making it more difficult for knots to hold securely.

In contrast, other suture materials like silk and catgut usually have greater friction due to their multifilament structures or texture, helping them to maintain knot security. Polyester, also being a multifilament option, offers better knot interlocking that enhances hold. Thus, when considering sutures that are prone to coming untied, monofilament is distinct for its properties that allow knots to slip more readily, making it the correct choice in this scenario.