A quick, portable and reliable tool for predicting ACL injury could be an invaluable instrument for athletes, coaches, and clinicians. The gold standard, Vicon motion analysis, despite having a high sensitivity and risk specificity, is not practical for coaches or clinicians to use on a routine basis for assessing athletes. The present study validated the Kinect device to the currently used method of chart review in predicting athletes at high risk.

A total of 114 participants were recruited from both the men and women McGill Varsity Sports Program. 69 males and 45 female athletes were evaluated to assess the specificity and sensitivity of the Kinect device in predicting athletes at high risk of injury. Each athlete performed three-drop vertical jumps off of a 31cm box and the data was recorded and risk score was generated. Generation of this data is done by our uniquely programmed software that measures landing angles at different time frames and compares live results to previously known data of injured athletes. A chart review was then performed by a clinician, blinded to these risk scores, to risk stratify the same athletes as high or low risk of ACL injury based on their medical charts. Data reviewed incorporated pre-season physical exams along with documented known risk factors for ACL injury, including previous knee injuries, family history of ACL injury, gender, sport, and BMI. Positive risk factors were assigned one point while negative risk factors assigned zero points.

The Kinect device, powered by our software, identified 40 athletes as having a high-risk score (> 55%), and subsequently, five (4.39%) sustained an ACL injury by the end of their respective sport seasons. Two male and two female basketball players along with one male soccer player sustained non-contact ACL injuries. Given that all five of the injured athletes were in the cohort of 40 identified as high risk by the Kinect, this yielded a sensitivity of 100% for the device. As for the specificity, the Kinect computed 35 false positives, yielding a specificity of 68% for the duration of the study. The medical chart review identified 36 athletes as high risk and 60 as being low risk of ACL injury. Four of the athletes that sustained an ACL injury were in the group of 36 identified as high risk by the clinician. However, one of the five participants who sustained an ACL injury was not captured by the medical chart assessment, yielding a sensitivity of 80% and a specificity of 65% for the clinician.

When it comes to injury prediction, it is preferred to have a high sensitivity even if the specificity is slightly lower as this ensures that all athletes who are at risk will be captured. Our data demonstrated that the chart analysis provided one false negative and led to missing one high-risk athlete who ended up sustaining an ACL injury. Based on the comparison of sensitivity and specificity, the Kinect system provides a slightly better predictive analysis for predicting ACL injury compared to chart review.

Our study is still in progress. The results mentioned in the abstract are preliminary results. The final results will be provided at the time of presentation.

Over the past decade, the widespread availability of high-resolution ultrasonography coupled with advances in regional anaesthesia have popularised peripheral nerve blocks for anterior cruciate ligament reconstructions (ACLRs). The aim of this study is to investigate whether the femoral nerve block (FNB) administered at the time of ACLR has any long-term impact on the quadriceps strength as compared to patients who did not receive a FNB.

This is a retrospective study. Four hundred charts of patients who underwent ACLR at our institution and had subsequent Biodex testing (an isokinetic rehabilitation test that provides objective information about muscle strength deficits and imbalances of the operated leg compared to the non-operated leg) from 2004 to 2015 were reviewed. Patients who had prior ipsilateral knee surgery, multi-ligament knee injury or at extreme ages were excluded from the study. The following baseline patient characteristics was recorded for each reviewed chart: age, sex, medical comorbidities, the date of the injury, date of the surgery, surgery technical notes and associated procedures, the surgeon, the hospital were the patient was operated, the Biodex test date and the Biodex test results. Data extraction assessed any association between the ACLR patients' who received FNB with the results of the Biodex test after completing the rehabilitation protocol. Descriptive statistics were used to compare the type of anaesthesia, mode of pain control and the results of the Biodex tests between patients grouped by the mode of anaesthesia used at the time of surgery (FNB versus no FNB). A multivariate regression model then compared quadriceps strength (inferred by Biodex test results) between groups while controlling for baseline differences between groups.

Fifty five percent of the ACLR patients received FNB compared to 45% that did not receive FNB over the last 11 years of performing ACLRs (2004–2015) at our institute. Fifty percent of the patients that received FNB failed to achieve more than or equal to 80% quadriceps strength (compared to the contralateral non-operated leg) at 6 months on Biodex test. On the other hand, only 20% of the non-FNB group failed to achieve more than or equal to 80% quadriceps strength.

This study lead us to think that ACLR patients that received FNB are significantly weaker in quadriceps strength at 6 months post ACLR in comparison to non-FNB ACLR patients. This finding subsequently might affect the time needed to return to sports and might indicate a considerable clinical consequence of the FNB on ACL-reconstruction patients.

Purpose

Twelve case reports of distal femur fractures as post-operative complications after anterior cruciate ligament (ACL) reconstruction have been described in the literature. The femoral tunnel has been suggested as a potential stress riser for fracture formation. The recent increase in double bundle ACL reconstructions may compound this risk. This is the first biomechanical study to examine the stress riser effect of the femoral tunnel(s) after ACL reconstruction. The hypotheses tested in this study are that the femoral tunnel acts as a stress riser to fracture and that this effect increases with the size of the tunnel (8mm versus 10mm) and with the number of tunnels (one versus two).