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Dr Duong Nguyen MPC

MD, FRCSC, MSc(ClinEpi), DipABOS, DipSportsMed(ABOS), FAAOS, CIME, DESS(c), DipSportMed(CASEM), Adjunct Clinical Professor - McMaster University

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Sports Medicine Surgery

The ACL corner - Evidence in Action

An up-to-date critical review of the current literature

J Bone Joint Surg Am. 2014 Feb 19;96(4):292-300.

Does ACL Reconstruction Alter Natural History?: A Systematic Literature Review of Long-Term Outcomes.

Chalmers PN1, Mall NA2, Moric M3, Sherman SL4, Paletta GP4, Cole BJ1, Bach BR Jr1.

Author information



Anterior cruciate ligament (ACL) injury can lead to tibiofemoral instability, decreased functional outcomes, and degenerative joint disease. It is unknown whether ACL reconstruction alters this progression at long-term follow-up.


A systematic literature review of the long-term results (minimum follow-up, more than ten years) after operative intra-articular reconstruction of ACL injuries and after nonoperative management was performed to compare (1) knee stability on physical examination, (2) functional and patient-based outcomes, (3) the need for further surgical intervention, and (4) radiographic outcomes. After application of selection criteria, forty patient cohorts with a mean of 13.9 ± 3.1 years of postoperative follow-up were identified. Twenty-seven cohorts containing 1585 patients had undergone reconstruction, and thirteen containing 685 patients had been treated nonoperatively.


Comparison of operative and nonoperative cohorts revealed no significant differences in age, sex, body mass index, or rate of initial meniscal injury (p > 0.05 for all). Operative cohorts had significantly less need for further surgery (12.4% compared with 24.9% for nonoperative, p = 0.0176), less need for subsequent meniscal surgery (13.9% compared with 29.4%, p = 0.0017), and less decline in the Tegner score (-1.9 compared with -3.1, p = 0.0215). A difference in pivot-shift test results was observed (25.5% pivot-positive compared with 46.6% for nonoperative) but did not reach significance (p = 0.09). No significant differences were seen in outcome scores (Lysholm, International Knee Documentation Committee [IKDC], or final Tegner scores) or the rate of radiographically evident degenerative joint disease (p > 0.05 for all).


At a mean of 13.9 ± 3.1 years after injury, the patients who underwent ACL reconstruction had fewer subsequent meniscal injuries, less need for further surgery, and significantly greater improvement in activity level as measured with the Tegner score. There were no significant differences in the Lysholm score, IKDC score, or development of radiographically evident osteoarthritis.


Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Am J Sports Med. 2013 Dec 4. [Epub ahead of print]

Anterior Cruciate Ligament Tears in Children and Adolescents: A Meta-analysis of Nonoperative Versus Operative Treatment.


BACKGROUND:Debate regarding the optimal initial treatment for anterior cruciate ligament (ACL) injuries in children and adolescents has not resulted in a clear consensus for initial nonoperative treatment or operative reconstruction.Hypothesis/ PURPOSE:The purpose of this meta-analysis was to systematically analyze aggregated data from the literature to determine if a benefit exists for either nonoperative or early operative treatment for ACL injuries in the pediatric patient. The hypothesis was that combined results would favor early operative reconstruction with respect to posttreatment episodes of instability/pathological laxity, symptomatic meniscal tears, clinical outcome scores, and return to activity. STUDY DESIGN:Meta-analysis.

METHODS:A literature selection process included the extraction of data on the following clinical variables: symptomatic meniscal tears, return to activities, clinical outcome scores, return to the operating room, and posttreatment instability/pathological laxity. A symptomatic meniscal tear was defined as occurring after the initial presentation, limiting activity, and requiring further treatment. Instability/pathological laxity was defined for the sake of this study as having an episode of giving way, a grade ≥2 Lachman/pivot-shift test result, or a side-to-side difference of >4 mm as measured by the KT-1000 arthrometer. All studies were evaluated using a formal study quality analysis. Meta-analysis was conducted for aggregated data in each category.

RESULTS:Six studies (217 patients) comparing operative to nonoperative treatment and 5 studies (353 patients) comparing early to delayed reconstruction were identified. Three studies reported posttreatment instability/pathological laxity; 13.6% of patients after operative treatment experienced instability/pathological laxity compared with 75% of patients after nonoperative treatment (P < .01). Two studies reported symptomatic meniscal tears; patients were over 12 times more likely to have a medial meniscal tear after nonoperative treatment than after operative treatment (35.4% vs 3.9%, respectively; P = .02). A significant difference in scores between groups was noted in 1 of 2 studies reporting International Knee Documentation Committee (IKDC) scores (P = .002) and in 1 of 2 studies reporting Tegner scores (P = .007). Two studies reported return to activity; none of the patients in the nonoperative groups returned to their previous level of play compared with 85.7% of patients in the operative groups (P < .01). Study quality analysis revealed that the majority of the studies were inconsistent in reporting outcomes.

CONCLUSION:Meta-analysis revealed multiple trends that favor early surgical stabilization over nonoperative or delayed treatment. Patients after nonoperative and delayed treatment experienced more instability/pathological laxity and inability to return to previous activity levels than did patients treated with early surgical stabilization.


adolescent, anterior cruciate ligament (ACL), management, meta-analysis, pediatricACLreconstruction

Am J Sports Med. 2013 Jun;41(6):1310-8. doi: 10.1177/0363546513482718. Epub 2013 Apr 5.

Gait patterns differ between ACL-reconstructed athletes who pass return-to-sport criteria and those who fail.



The current standard of practice for an athlete to return to sport after anterior cruciate ligament (ACL) reconstruction is varied. Attempt to return to activity is typically advised 6 months after surgery, but functional performance deficits and gait abnormalities are often still evident and may have important implications on future function.


When comparing the involved and uninvolved limbs, patients who failed return-to-sport (RTS) criteria would demonstrate (1) smaller peak knee angles, extensor moments, and peak power absorption at the knee of the involved limb and (2) larger peak hip angles, extensor moments, and peak power generation of the involved limb.


Controlled laboratory study.


A total of 42 patients completed functional and biomechanical gait assessment 6 months after ACL reconstruction. Functional testing involved an isometric quadriceps strength test, 4 single-legged hop tests, and 2 self-report questionnaires. Three-dimensional motion analysis was used to measure sagittal plane kinematics and kinetics of the hip and knee. A mixed-model analysis of variance and post hoc t tests were used to compare the limb symmetry of those who passed and those who did not pass RTS criteria. Minimal clinically important differences were calculated from healthy gait data and used to further define meaningful limb asymmetries.


Twenty of the 42 (48%) patients passed RTS criteria 6 months after ACL reconstruction. Patients who did not pass the criteria demonstrated statistically significant differences between limbs on all kinematic and kinetic variables at the knee (P ≤ .027). Clinically meaningful asymmetries at the hip were also identified in this group. Only kinetic asymmetries at the knee were identified in the patients who passed RTS criteria.


Athletes who demonstrate superior functional performance 6 months after ACL reconstruction may have fewer abnormal and asymmetrical gait behaviors than their poorer performing counterparts. Patients who did not pass RTS criteria not only demonstrated larger kinematic and kinetic asymmetries between limbs but also appeared to use a gait strategy more closely aligned with athletes early after ACL rupture.


Poor performance on a battery of functional performance measures may be related to the presence of movement asymmetries in athletes after ACL reconstruction. Objective RTS criteria have the potential to provide information to clinicians who determine when these athletes return to activity, and may aid in the prescription of targeted rehabilitation to address underlying movement asymmetry.


ACL reconstruction, function, gait mechanics, noncopers, return to sport

Arthroscopy. 2014 Feb;30(2):245-55. doi: 10.1016/j.arthro.2013.10.009. Epub 2013 Dec 30.

Neuromuscular retraining intervention programs: do they reduce noncontact anterior cruciate ligament injury rates in adolescent female athletes?



The purpose of this study was to identify neuromuscular training intervention programs that significantly reduced the incidence of noncontact anterior cruciate ligament (ACL) injury rates in female adolescent athletes.


A systematic search of PubMed was conducted to determine the outcome of ACL neuromuscular retraining programs in a specific population. The inclusion criteria were English language, published from 1994-2013, original clinical trials, all evidence levels, female athletes aged 19 years or younger, and noncontact ACL injury incidence rates determined by athlete-exposures.


Of 694 articles identified, 8 met the inclusion criteria. Three training programs significantly reduced noncontact ACL injury incidence rates in female adolescent athletes. These were the Sportsmetrics, Prevent Injury and Enhance Performance, and Knee Injury Prevention programs. The estimated number of athletes who needed to train to prevent 1 ACL injury in these 3 studies ranged from 70 to 98, and the relative risk reduction ranged from 75% to 100%. Five programs did not significantly reduce noncontact ACL injury incidence rates. The ACL injury incidence rates for control subjects were lower in these studies (0.03 to 0.08 per 1,000 athlete-exposures) than in those investigations that had a significant effect (0.21 to 0.49 per 1,000 athlete-exposures). There was wide variability among all programs in the frequency, duration, and timing of training; how training was conducted, supervised, or controlled; the components of the program; how exposure data were calculated; noncontact ACL injury incidence rates in the control groups; and compliance with training.


Three ACL intervention programs successfully reduced noncontact ACL injury incidence rates in female adolescent athletes. Pooling of data of all ACL intervention programs is not recommended because of numerous methodologic differences among studies.


Level II, systematic review of Level I and II studies.