Fixation of distal clavicle fractures with coracoclavicular instability: a comparative biomechanical study in human cadavers

Abstract

Background The need for coracoclavicular (CC) stabilization in the fixation of fractures with CC instability (Neer type IIB and V) was biomechanically demonstrated by higher construct strength than isolated locking plate osteosynthesis. It was the purpose of this study to prove noninferiority of the new cow-hitch suture repair technique compared with the well-established suture tape double-button fixation with regard to overall fixation strength and cyclic loading properties. Methods Twelve human cadaver shoulders (7 right and 5 left) were matched for sex and age (mean age: 75 ± 5 years). An oblique parasagittal fracture line 20 mm medial to the acromioclavicular joint line was created, and the CC ligaments were dissected. Six shoulders were reconstructed by a double FiberTape fixation with two suture buttons (group DB), and the remaining six shoulders by a cow-hitch suture repair using a double FiberWire with only coracoid button fixation (group CH). Both reconstruction techniques were tested in a servo-hydraulic material testing machine for cyclic displacement (mm), stiffness (N/mm), and maximum load-to-failure (N) after 500 cycles at 3 mm/s and inferosuperior load between 15 and 70 N. Superior fragment displacement in space was recorded using a MicroScribe digitizer. Results There were no statistically significant differences regarding cyclic displacement (group DB: 0.7 mm; group CH: 1.3 mm; P = .36), stiffness (group DB: 177 N/mm; group CH: 116 N/mm; P = .17), maximum load-to-failure (group DB: 560 N; group CH: 492 N; P = .59), and superior displacement in space of the medial fragment (group DB: 3.2 mm; group CH: 1.6 mm; P = .48). Conclusion Fixation of unstable distal clavicle fractures using a double FiberWire cow-hitch suture repair with isolated coracoid button fixation for stand-alone CC stabilization resulted in similar biomechanical properties to a double-suture button fixation with FiberTapes while avoiding prominent clavicular implants.

Biomechanical evaluation of double stranded knot configurations in high strengths sutures and tapes

“…Several clinical reports on Nice-knots and Cow-hitch are available, yielding excellent results in cerclage treatment of periprosthetic fractures [3], fracture hemiarthroplasty [24], greater tuberosity repair in reverse total shoulder arthroplasty [4], all-suture distal clavicle fracture repair [5,19], and acromioclavicular joint repair [20]. However, there is a lack of literature evaluating the novel dynamic self-tightening suture materials in clinical scenarios.…”

“…Compared to the surgeons` knot, double-stranded knots are biomechanically stronger, stiffer, less bulky, and can preserve applied tension during tying better than conventional knots [2]. Therefore, they are suitable in orthopaedic procedures requiring resistance to high tensile forces, e.g., when using cerclage sutures for fracture xation [3], as well as during tubercle re xation after fracture hemiarthroplasty [4] or lateral clavicle fracture stabilization [5]. Although various double-stranded knot con gurations are described in the literature, in a biomechanical study by Meyer et al reported that Cow-hitch and Nice-knots are the best performing and technically most simple knots, best suited to exploit the enormous mechanical capabilities of modern high-strength suture materials [2] (Figure 1).…”

Biomechanical evaluation of fixation of the coracoclavicular stand-alone cow-hitch suture reconstruction in comparison to two established techniques for highly unstable distal clavicle fractures (Neer type V)

“… 10 , 20 We compared these with a simple CC suture reconstruction technique, the stand-alone cow-hitch technique, which has been introduced for AC joint stabilizations and distal clavicle fractures and was evaluated regarding biomechanical stability in Neer type II fractures with good results. 6 , 16 , 17 Previous biomechanical studies focused mainly on type II fractures. 16 , 33 A recent study by Laux et al 16 compared the cow-hitch suture reconstruction technique with the well-established suture tape double-button fixation for Neer type IIB fractures, with the cow-hitch suture reconstruction showing promising and noninferior results.…”

“… 6 , 16 , 17 Previous biomechanical studies focused mainly on type II fractures. 16 , 33 A recent study by Laux et al 16 compared the cow-hitch suture reconstruction technique with the well-established suture tape double-button fixation for Neer type IIB fractures, with the cow-hitch suture reconstruction showing promising and noninferior results. Therefore, this fairly novel, simple, and cost-effective technique 6 can be considered as a treatment option for Neer type V fractures as well.…”

Comparing the Anatomical Landmarks Versus the Coracoid-Based Landmarks Techniques for Coracoclavicular Stabilization After High-Grade Acromioclavicular Injury: A Biomechanical Study

“…We used a force of 70 N in both the vertical and horizontal directions to assess stability, based on previous studies. 7 , 13 , 15 , 24 , 25 A displacement rate of 1 mm/min was applied to the joint until the load cell force reached 70 N, and the displacement values and stiffness were recorded. Each joint underwent this process 3 times.…”