Technical considerations in manual and instrument tying techniques.

The purpose of this study was to relate the two-hand (manual) and instrument tie techniques with the ultimate security of granny and square knots constructed in multifilament and monofilament nylon sutures. Instrument-tie technique constructed secure granny and square knots, which failed by breakage rather than slippage. Similarly, two-hand (manual) tie techniques constructed square knots, which achieved knot security, failing only by breakage. In contrast, knot security was not reliably achieved with granny knots constructed by the two-hand (manual) tie techniques, with the knots frequently failing by slippage.