Your COA / Votre association
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protocol used reproducible landmarks only on either the scapula or the humerus respectively so as to avoid any variability secondary to the glenohumeral relationship in space. Glenoid offset and humeral offset were then measured independently using two different methods adapted from previously described planar radiographic techniques. The interobserver and intra-observer reliability were used to identify the optimal bone specific measurement techniques, which were subsequently used for functional analysis. The degree of association between glenohumeral offset and preoperative and postoperative functional outcomes was determined using a multivariable regression analysis. Results: The intra-class correlation coefficients for the preferred humeral and glenoid measurement methods were 0.83 and 0.75, respectively. After controlling for age and sex, postoperative glenoid and combined glenohumeral offset signifi-
cantly correlated with postoperative Constant Shoulder scores (p=0.019 and p=0.023 respectively). There was no significant correlation between preoperative functional scores and preoperative offset measurements. Additionally, no significant correlation was found between the change in GHO from preoperative to postoperative and functional outcomes. Conclusion: A highly reliable technique was developed and used to measure GHO using regular diagnostic CT scans in patients after TSA. Increased postoperative glenoid and combined glenohumeral offset are related to improved functional outcomes. However, there appears to be no relation of functional outcomes to change in GHO from preoperative to postoperative. This highlights the importance of surgically restoring the absolute value of pre-arthritic GHO as opposed to relative increases based on preoperative GHO.
CORA First Prize Poster Award ACL Reconstruction with Supplemental Tibial Fixation: a Biomechanical Study Comparing a Novel All-Soft Tissue Technique for Secondary Fixation with other Techniques Naser AlNusif, McGill University Jason Khoury, Fahad Abduljabbar, Naif Alhamam, Ron Dimentberg, Moreno Morelli Purpose: Fixation failure after an anterior cruciate ligament (ACL) reconstruction occurs more frequently at the tibial site. There are many different techniques and modalities used to supplement the tibial fixation in ACL reconstruction procedures. Those include: metal staples or bio-tenodesis screws. In certain cases, where bony supplemental fixation was used, poor bony purchase was observed. This is mainly seen in patients with poor bone quality, usually encountered in revision surgeries and patients with metabolic diseases. The objective of our study is to compare the biomechanical efficacy of bony versus soft tissue supplemental fixation. We hypothesize that ACL graft-tibial tunnel fixation with bio-interference screw supplemented with a novel technique using medial collateral ligament (MCL) fixation will provide superior strength in mechanical testing when compared to bio-interference screw plus a bio-tenodesis screw. Method: Twelve matched human knees (total of 24 specimens) were used and divided into two groups matched by gender, age, bone mineral density (BMD) and graft diameter. The first group will compare bio-interference screw (BIS) alone versus BIS + bony supplemental fixation “a bio-tenodesis screw”, while the second group will compare BISalone versus BIS + MCL supplemental fixation. In all specimens, the tibial tunnel was prepared using a standard and reproducible way by setting the tibial guide at 55 degrees. The graft was passed through the tibial tunnel and hooked on a custom made hook
COA Bulletin ACO - Fall/Winter - Automne/Hiver 2017
attached to a servohydraulic device. A bio-interference screw was inserted into the tibial tunnel of all specimens. For the bony supplemental fixation group, a bio-tenodesis screw was used. On the other hand, for the MCL supplemental fixation group, the graft was sutured to the superficial MCL using fiber sutures. Finally, all grafts were pre-tensioned then subjected to cyclical displacement followed by load to failure testing. Results: We expect that using supplemental fixation is superior than using a bio-interference screw alone. Furthermore, when comparing both methods of supplemental fixation, we predict that MCL supplemental fixation would be superior in poor bone quality specimens. Conclusion: Based on the expected results, our novel technique of MCL supplemental fixation would be a strong fixation option in all patients, but more importantly in patients with low BMD. Moreover, this technique is more cost effective than most other options of supplemental fixation.