Acromioclavicular joint suture button repair leads to coracoclavicular tunnel widening

Abstract

Purpose Biomechanical evaluation of three different suture button devices used in acromioclavicular joint repair and analysis of their effect on post-testing tunnel widening. Methods Eighteen human shoulder girdles were assigned into three groups with a similar mean bone mineral density. Three different single-tunnel acromioclavicular repair devices were tested: (1) AC TightRope® with FiberWire; (2) AC Dog Bone™ Button with FiberTape; (3) Low Profile AC Repair System. Biomechanical testing was performed simulating the complex movement of the distal clavicle as follows. A vertical load of 80 N was applied continuously. The rotation of the clavicle about its long axis was set at 10° anterior and 30° posterior for 2500 cycles at 0.25 Hz. The horizontal translation of the clavicle was set at 6 mm medial and 6 mm lateral for 10,000 cycles at 1 Hz. The coracoclavicular distance was measured before and after testing. After testing, each sample underwent micro-CT analysis. Following 3D reconstruction, the area of the bone tunnels was measured at five defined cross sections. Results In TightRope® and Dog Bone™ groups, all samples completed testing, whereas in the Low Profile group, three out of six samples showed system failure. The mean absolute difference of coracoclavicular distance after testing was significantly greater in the Low Profile group compared to TightRope® and Dog Bone™ groups (4.3 ± 1.3 mm vs 1.9 ± 0.7 mm vs 1.9 ± 0.8 mm; p = 0.001). Micro-CT analysis of the specimens demonstrated significant tunnel widening in the inferior clavicular and superior coracoid regions in all three groups (p < 0.05). Conclusion Significant tunnel widening can be observed for all devices and is primarily found in the inferior parts of the clavicle and superior parts of the coracoid. The Low Profile AC Repair System showed inferior biomechanical properties compared to the AC TightRope® and AC Dog Bone™ devices. Therefore, clinicians should carefully select the type of acromioclavicular repair device used and need to consider tunnel widening as a complication.

Clavicular tunnel widening after acromioclavicular joint reconstruction: comparison between single and double clavicular tunnel techniques

“…More recently, the phenomenon of tunnel widening of the clavicular tunnels has gained attention and could attribute to an increased risk of loss of reduction and clavicle fractures 2 . Recent clinical studies however do not support a relationship between tunnel widening and loss of reduction or clinical outcome [12][13][14] . Studies investigating this phenomenon detected a tunnel widening in up to 100% of the patients, with a mean increase in tunnel diameter of 18-66% [12][13][14][15] .…”

In Vivo Analysis of Acromioclavicular Kinematics and Distance During Multiplanar Humeral Elevation

“…The current study showed posterior translation of the distal clavicle relative to the scapula with shoulder motion, implying that the reconstructed CC ligament might be overstressed on the anterior part of the clavicular tunnel with shoulder movements, resulting in cumulative damage over time. 4,6 Meanwhile, it was reported that the distal clavicle translates posteriorly because of traction of the upper trapezial muscle when AC dislocations occur. 9 Consequently, an anterior-inferior tunnel from the superior-posterior clavicular surface instead of a vertical one is more likely to provide native stability and should be considered.…”

No correlation exists between coracoid tunnel widening and loss of reduction after arthroscopic acromioclavicular fixation using tightrope system

“…Furthermore, this is the first in vivo study to draw attention to the possible cause of failure and attempt to correlate it to coracoid tunnel widening. An in vitro study by Dalos et al used micro-CT analysis to assess coracoid and clavicular tunnel widening and compared them across three different repair systems [ 10 ]. They reported tunnel widening at 5 different tunnel cross sections and found that tunnel widening mainly occurs at the inferior part of the clavicular tunnel followed by the superior part of the coracoid tunnel.…”

“…The concept of arthroscopic-assisted fixation of acute ACJ injury is to use suspensory devices to maintain the coracoclavicular distance and facilitate healing of the CC and AC ligaments [ 21 , 26 ]. These suspensory devices require the drilling of tunnels into the clavicle and the coracoid, which yields complications, such as fracture of the distal clavicle and coracoid and tunnel widening with biomechanical consequences [ 10 , 22 ]. Also, loss of reduction is a commonly found complication with an incidence ranging from 12 to 80% after arthroscopic techniques [ 9 , 11 , 21 , 29 ].…”