d)
A "three-loop pulley" suturing technique is used which produces 5 "straight-pull" load bearing elements and 1 "knot-pull" (see Figure Q2). A 4-gauge suture is selected which has a cross-sectional diameter of 0.2 mm. Determine the maximum load that can be sustained.
e)
The chromic catgut suture is braided, whilst the polyglycolic acid suture is monofilament. Evaluate what implications this may have for the suture's rate of biodegradation.
f)
In the early phase of her recovery, she will require additional support at her ankle to restrict movement. Sketch a design for the support, justifying the design features incorporated.
g)
For how long a period should she be using the support you designed in f? Your answer must cross-reference the design features showcased in f.
1200
Straight-Pull Knot-Pull
Engineering Strain = 1.0 (Active Length Doubles)
900 stress (MPa) 600 Engineering 300
Polyglycolic acid Figure Q2B-Left Three-loop pulley suturing technique; (Right) Tensile strengths of 4 biomaterials 2 non-absorbable and 2 absorbable