Additive fiber-cerclages in proximal humeral fractures stabilized by locking plates

Figures & data

Figure 1. A. Right shoulder: osteotomy of the greater tuberosity. SSP: M. supraspinatus; SSC: M. subscapularis; ….> bicipital groove. B. Placeholder (superimposed display and arrow) in gap l to retain a 2-mm gap between the head and greater tuberosity fragment during plate fixation.

Figure 2. A. Unstable 3-part fracture model with fiber-cerclages of the proximal humerus intact rotator cuff. Fracture gap I (à) and II (- ->). Three point-pairs (….>) for measurement of rotator cuff strain. B. AP and C. axillary views of an unstable 3-part-fracture model.

Figure 3. The experimental setup. SSP: M. supraspinatus; ISP-TM: M. infraspinatus and m. teres minor; SSC: M. subscapularis; UMS: ultrasonic measuring system; FMS: force moment sensor; RASS: robot-assisted shoulder simulator; FC-HC: force-controlled hydraulic cylinder; CS: control station.

Table 1. Three-dimensional motions in gap I and II in four physiological-like load cases with (n = 12) and without (n = 12) additive fiber-cerclage. Mean (SD) in mm

	Axial load in 0° abduction	Axial load in 60° abduction	Internal rotation	External rotation
Gap I
with cerclage	0.29 (0.25)	0.33 (0.22)	0.19 (0.23)	0.21 (0.18)
without cerclage	0.34 (0.28)	0.34 (0.30)	0.20 (0.15)	0.19 (0.17)
p-value	0.5	0.7	0.5	0.9
Gap II
with cerclage	1.16 (1.20)	0.91 (0.84)	0.38 (0.37)	0.62 (0.68)
without cerclage	1.12 (0.83)	0.75 (0.61)	0.49 (0.41)	0.31 (0.23)
p-value	1.0	0.7	0.3	0.3

Table 2. Vertical motions (z-axis motions) in physiological-like load cases with (n = 12) and without (n = 12) additive fiber-cerclage. Mean (SD) in mm

	Axial load in 0° abduction	Axial load in 60° abduction
GAP I
with cerclage	0.79 (0.99)	0.34 (0.28)
without cerclage	0.53 (0.65)	0.42 (0.29)
p-value	0.4	0.5
GAP II
with cerclage	2.12 (1.37)	1.06 (0.83)
without cerclage	1.24 (0.92)	0.75 (0.45)
p-value	0.05	0.5

Figure 4. Measurement of rotator cuff strain with (n = 12) and without (n = 12) additive fiber-cerclage. SSC: M. subscapularis; SSP: M. supraspinatus; ISP+TM: M. infraspinatus and m. teres minor.