Impact of Tunnels and Tenodesis Screws on Clavicle Fracture: A Biomechanical Study of Varying Coracoclavicular Ligament Reconstruction Techniques
The purpose of this study was to compare the load to fracture of distal clavicles with no tunnels, one tunnel, or 2 tunnels and to evaluate the effect of inserting tenodesis screws in the tunnels on load to fracture of the distal clavicle.
Fifty right sawbone clavicles were obtained and divided into 5 groups (n = 10): group 1, normal clavicle; group 2, one tunnel, no tenodesis screw; group 3, 2 tunnels, no tenodesis screws; group 4, one tunnel with tenodesis screw; and group 5, 2 tunnels with 2 tenodesis screws. Tunnels were created using a 5-mm-diameter reamer, and 5.5 × 10 mm polyethyl ethyl ketone tenodesis screws were used. A 4-point bending load was applied to the distal clavicles. Load to failure was noted for each specimen.
Load to failure in clavicles without tunnels was significantly higher (1,157.18 ± 147.10 N) than in all other groups (P < .0005). No statistical differences were noted between groups 2, 3, 4, and 5. Load to failure was not statistically different in clavicles with one versus 2 tunnels. In addition, the use of tenodesis screws in the tunnels did not affect the load required to fracture.
The use of tunnels in the clavicle for coracoclavicular (CC) ligament reconstruction significantly reduces the load required to fracture the distal clavicle. The addition of tenodesis screws does not appear to significantly increase the strength of the clavicle in this construct.
CC ligament reconstruction techniques commonly use tunnels in the distal clavicle, which may render the clavicle more susceptible to fracture. This study helps quantify the effect of these tunnels on the strength of the distal clavicle.
Available from: Ulrich Spiegl
[Show abstract] [Hide abstract]
Lateral clavicle fractures have been reported following coracoclavicular (CC) ligament reconstruction with bone tunnels through the clavicle. Several techniques for CC reconstruction with different drill-hole measurements have been described. Our objective was to evaluate clavicle weakening related to tunnel diameters for common CC-reconstruction techniques.
Testing was performed on 2 groups of 18 matched pair clavicles, which were randomly distributed between groups. There were no significant differences between the groups regarding bone mess density (BMD), clavicle width, age, and gender. One clavicle from each pair was prepared according to one of two reconstruction techniques; the contralateral clavicle was left intact. Both techniques placed 2 tunnels through the medial clavicle, 30 mm and 45 mm from the lateral border. Group 1 (mean age: 53, range: 44-63; mean BMD: 0.48, range: 0.39-0.59) was prepared with 2.4 mm tunnels and augmentation devices. Group 2 (mean age: 56, range: 45-63; mean BMD: 0.47, range 0.35-0.61) was prepared with 6.0 mm tunnels with hamstring grafts and tenodesis screws. A 3-point bending load was applied to the distal clavicles at 15 mm/min until failure. Ultimate failure load and anterior-posterior width 45 mm medial from the lateral border were recorded for each specimen. Strength reduction was determined as the percent reduction in ultimate failure load between paired intact and surgically prepared clavicles. Relative tunnel size was determined as the quotient of tunnel diameter and clavicle width. An independent observer performed all clavicle width measurements. Non-parametric statistics were used (MWU, Kendall’s Tau).
The 6.0 mm technique significantly reduced clavicle strength relative to intact (p = 0.02) and caused significantly more strength reduction than the 2.4 mm technique (p = 0.02) (Figure). The 2.4 mm technique was not significantly different from intact. All but one fractures occurred at the medial tunnel. Clavicle width at the medial hole varied highly (mean: 18.1 mm, range: 12.3 - 27.1 mm). There was a significant approximately linear correlation between clavicle width and strength reduction (p = 0.04, tau = -0.36) and between relative tunnel size and strength reduction (p < 0.01, tau = 0.51). Therefore, clavicle strength reductions of 30% and 50% relative to the intact state can be expected with relative tunnel diameters of 34.5% and 49.8% of the clavicle width, respectively. The intra-observer correlation coefficient of the width measurement was excellent (0.99; 95% CI: 0.98 - 0.99).
Coracoclavicular ligamentous reconstruction with 6.0 mm tunnels, graft, and tenodesis screws caused significantly greater decreases in the strength of the clavicle when compared to 2.4 mm tunnels with augementation devices and undrilled controls. Additionally, strength reductions correlated highly with the ratio of tunnel width relative to overall clavicle width. This information can help optimize techniques for reconstructing unstable distal clavicles and can influence the intraoperative decision-making process based on the individual clavicle width.
[Show abstract] [Hide abstract]
ABSTRACT: Management strategies for acromioclavicular (AC) joint injuries depend heavily on the severity of the injury. Operative treatment is typically indicated for Rockwood grades IV-VI injuries and selected grade III injuries, especially after failure of nonoperative management. When surgical treatment is indicated, we prefer to reconstruct the unstable AC joint using an anatomic coracoclavicular ligament reconstruction (ACCR) technique with tendon graft looped around both the coracoid and the clavicle. The purpose of this article is to present the biomechanical rationale, our detailed surgical technique and reported clinical outcomes for ACCR with tendon graft.
Available from: Xinning Li
[Show abstract] [Hide abstract]
ABSTRACT: Complications of the acromioclavicular joint injuries can occur as a result of the injury itself, conservative management, or surgical treatment. Fortunately, the majority of acromioclavicular surgeries utilizing modern techniques and instrumentation result in successful outcomes. However, clinical failures do occur with frequency. The ability to identify the causative factor of failures makes revision surgery more likely to be successful. The purposes of this review are to highlight common problems that can occur following acromioclavicular joint surgery and discuss techniques that can be utilized in revision surgery.
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.