Orthopaedic Department, St George Hospital, Sydney, NSW, 2217, Australia.
UNSW, Sydney, Australia.
Knee Surg Sports Traumatol Arthrosc. 2018 Dec;26(12):3818-3825. doi: 10.1007/s00167-018-4999-y. Epub 2018 Jun 20.
The self-reinforcement mechanism after double row suturebridge rotator cuff repair generates increasing compressive forces at the tendon footprint with increasing tendon load. Passive range of motion is usually allowed after rotator cuff repair. The mechanism of self-reinforcement could be adversely affected by shoulder abduction.
Rotator cuff tears were created ex vivo in nine pairs of ovine shoulders. Two different repair techniques were used. One group was repaired using a double row 'suturebridge' construct with tied horizontal medial row mattress sutures (Knotted repair group). The other group was repaired identically except that medial row knots were not tied (Knotless repair group). Footprint compression was measured at varying amounts of abduction and under tendon loads of 0, 10, 20, 30, 40, 50 and 60N. The rate of increase of contact pressure (degree of self-reinforcement) was calculated for each abduction angle.
Abduction diminishes footprint contact pressure in both knotted and knotless double row suturebridge constructs. Progressive abduction from 0 to 40 abduction in the knotless group and 0-30 in the knotted group results in a decrease in self-reinforcement. Abduction beyond this does not cause a further decrease in self-reinforcement. There was no difference in the rate of increase of footprint contact pressure at each angle of abduction when comparing the knotted and knotless groups.
In the post-operative period, high tendon load combined with minimal abduction would be expected to generate the greatest amount of footprint compression which may improve tendon healing. Therefore, to maximize footprint compression the use of abduction pillows should be avoided while early isometric strengthening should be used.
双排缝线桥修复肩袖后，自身增强机制会随着肌腱负荷的增加而在肌腱止点处产生更大的压缩力。肩袖修复后通常允许进行被动活动范围。肩外展会对自身增强机制产生不利影响。
在 9 对羊肩离体上创建肩袖撕裂。使用两种不同的修复技术。一组使用带有水平内侧褥式缝线打结的双排“缝线桥”结构（打结修复组）进行修复。另一组采用相同的方法修复，但不打结内侧褥式缝线（无结修复组）。在不同的外展角度下测量止点的压缩力，并在 0、10、20、30、40、50 和 60N 的肌腱负荷下进行测量。计算每个外展角度下接触压力的增加率（自身增强程度）。
在打结和无结双排缝线桥结构中，外展都会减小止点的接触压力。无结组从 0 度到 40 度外展，以及打结组从 0 度到 30 度外展，逐渐增加外展会导致自身增强程度降低。超过这个角度，不会进一步降低自身增强程度。比较打结组和无结组，在每个外展角度下，止点接触压力的增加率没有差异。
在术后阶段，高肌腱负荷和最小的外展角度预计会产生最大的止点压缩，从而可能促进肌腱愈合。因此，为了最大限度地增加止点的压缩，应避免使用外展枕，而应早期使用等长强化。
