Return to play and future ACL injury risk after ACL reconstruction in soccer athletes from the Multicenter Orthopaedic Outcomes Network (MOON) group

Factors Influencing Return to Play and Second Anterior Cruciate Ligament Injury Rates in Level 1 Athletes After Primary Anterior Cruciate Ligament Reconstruction: 2-Year Follow-up on 1432 Reconstructions at a Single Center

BACKGROUND

Despite the importance of return-to-play (RTP) rates, second anterior cruciate ligament (ACL) injury rates, and patient-reported outcomes of athletes returning to sports after ACL reconstruction (ACLR), these outcomes have not been evaluated together across a single cohort nor the pre- and intraoperative factors influencing outcomes explored.

PURPOSE

To prospectively report outcomes after ACLR relating to RTP, second ACL injury, and International Knee Document Committee (IKDC) scores in a large cohort of athletes at a single center to examine the influence of pre- and intraoperative variables on these outcomes.

DESIGN

Cohort study; Level of evidence, 3.

METHODS

A consecutive cohort of 1432 athletes undergoing primary ACLR by 2 orthopaedic surgeons was followed up prospectively more than 2 years after surgery. Pre- and intraoperative findings were reported with outcomes at follow-up relating to RTP, second ACL injury, and IKDC. Between-group differences for each outcome were reported and the predictive ability of pre- and intraoperative variables relating to each outcome assessed with logistic regression.

RESULTS

There was >95% follow-up 2 years after surgery. The RTP rate was 81%, and of those who returned, 1.3% of those with patellar tendon grafts and 8.3% of those with hamstring grafts experienced ipsilateral rerupture (hazard ratio, 0.17). The contralateral ACL injury rate was 6.6%, and the IKDC score at follow-up was 86.8, with a greater proportion of patients with patellar tendon grafts scoring <80 on the IKDC (odds ratio, 1.56; 95% CI, 1.15-3.12). There was no relationship between time to RTP and second ACL injury, and there was a moderate correlation between ACL-Return to Sport After Injury score and RTP at follow-up (P < .001, rho = 0.46). There were a number of differences in pre- and intraoperative variables between groups for each outcome, but they demonstrated a poor ability to predict outcomes in level 1 athletes at 2-year follow-up.

CONCLUSION

Findings demonstrated high overall RTP rates, lower reinjury rates with patellar tendon graft after 2-year follow-up in level 1 athletes, and no influence of time to RTP on second ACL injury. Despite differences between groups, there was poor predictive ability of pre- and intraoperative variables. Results suggest pre- and intraoperative variables for consideration to optimize outcomes in level 1 athletes after ACLR, but future research exploring other factors, such as physical and psychological recovery, may be needed to improve outcome prediction after ACLR.

REGISTRATION

NCT02771548 (ClinicalTrials.gov identifier).

Risk Factors for Early Subsequent (Revision or Contralateral) ACL Reconstruction: A Retrospective Database Study

Background:

Many factors contribute to the risk for subsequent anterior cruciate ligament reconstruction (ACLR) within 2 years from the index procedure.

Purpose/Hypothesis:

The purpose of this study was 2-fold: (1) to evaluate the incidence of subsequent (revision or contralateral) ACLR at 2 years in a large cohort and (2) to explore the association between patient-specific factors and early subsequent ACLR risk by age group. We hypothesize that 2-year subsequent (revision or contralateral) ACLR rates will be low and that risk factors for subsequent (revision or contralateral) ACLR will vary depending on a patient’s age group.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

The California Office of Statewide Health Planning and Development Ambulatory Surgery Database was retrospectively reviewed to assess the incidence of 2-year subsequent (revision or contralateral) ACLR and to identify patient-specific risk factors for early subsequent (revision or contralateral) ACLR by age group between 2005 and 2014.

Results:

Of 94,108 patients included, the rate of subsequent (revision or contralateral) ACLR was highest in patients younger than 21 years (2.4 per 100 person-years; 95% CI, 2.3-2.6) and lowest in those older than 40 years (1.3 per 100 person-years; 95% CI, 1.2-1.4). Younger age, white race (compared with Hispanic in all age groups and Asian in age <21 or >40 years), private insurance if age younger than 21 years, public insurance or worker's compensation claims if age older than 30 years were significantly associated with an increased risk of subsequent (revision or contralateral) ACLR at 2 years.

Conclusion:

Results of the present study provide insight into subsequent (revision or contralateral) ACL reconstruction, which can be used to assess and modify treatment for at-risk patients and highlight the need for data mining to generate clinically applicable research using national and international databases.

Clinical Outcomes of Arthroscopic Primary Anterior Cruciate Ligament Repair: A Systematic Review from the Scientific Anterior Cruciate Ligament Network International Study Group

PURPOSE

To perform a systematic review of contemporary studies reporting clinical outcomes of primary anterior cruciate ligament (ACL) repair to determine whether these studies demonstrate any significant benefit of ACL repair and whether there is evidence of a deterioration of mid-term outcomes as seen in historical data.

METHODS

A systematic review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. A PubMed search using the keywords "repair" AND "Anterior Cruciate Ligament" was performed (limits: English language, publication date between January 1, 2014, and January 13, 2019). All identified studies reporting clinical outcomes of arthroscopic ACL repair were included. Critical appraisal was conducted using the Cochrane Risk of Bias Tool for Randomized Clinical Trials and the Methodological Index for Non-Randomized Studies. Basic parameters of each study including population characteristics, repair technique, physical examination findings, and clinical outcome scores were recorded and evaluated.

RESULTS

Nineteen eligible studies were identified (including 5 comparative studies). None of the comparative studies showed any significant difference between repair and reconstruction groups with respect to International Knee Documentation Committee (IKDC), Lysholm, Tegner, side-to-side laxity difference, Lachman, pivot shift tests, or graft rupture rates. Four non-comparative studies reported outcomes at medium- to long-term follow up (range of mean follow up 43.3-79 months) with a mean Lysholm score between 85.3 and 100, mean IKDC subjective score between 87.3 and 100, and mean Tegner activity score between 5 and 7.

CONCLUSIONS

Comparative studies identified no significant differences between ACL repair and reconstruction with respect to Lysholm, IKDC, side-to-side laxity difference, pivot shift grade, or graft rupture rates. However, these studies had major limitations including small numbers and short durations of follow up. Case series demonstrated that excellent outcomes can be achieved at medium- to long-term follow up with the SAR technique.

LEVEL OF EVIDENCE

IV; Systematic review of Level II to IV investigations.

Quadriceps Neuromuscular and Physical Function After Anterior Cruciate Ligament Reconstruction

CONTEXT

Persistent neuromuscular deficits in the surgical limb after anterior cruciate ligament reconstruction (ACLR) have been repeatedly described in the literature, yet little is known regarding their association with physical performance and patient-reported function.

OBJECTIVE

To describe (1) interlimb differences in neuromuscular and functional outcomes and (2) the associations of neuromuscular outcomes with measures of physical and knee-related patient-reported function.

DESIGN

Cross-sectional study.

SETTING

Laboratory.

PATIENTS OR OTHER PARTICIPANTS

Thirty individuals after primary, unilateral ACLR (19 males; age = 21.5 years [range, 14-41 years]; 8 months [range = 6-23 months] postsurgery).

MAIN OUTCOME MEASURE(S)

Knee-extensor isometric and isokinetic peak torque was measured with an isokinetic dynamometer. Cross-sectional area (CSA) was measured bilaterally for each of the quadriceps muscles via magnetic resonance imaging. We measured quadriceps central activation bilaterally via the superimposed-burst technique. Physical performance (single-legged hop tests, step length via spatiotemporal gait analysis) and patient-reported outcomes (International Knee Documentation Committee questionnaire and Knee Injury and Osteoarthritis Outcome Score Sport and Recreation subscale) were also recorded. We conducted Wilcoxon signed rank tests to identify interlimb differences. Spearman ρ correlation analyses revealed associations between limb symmetry and neuromuscular and functional outcomes, as well as with patient-reported function.

RESULTS

Deficits in the surgical limb as compared with the nonsurgical limb were present for all outcomes (P values < .05). Greater single-legged hop-test symmetry (83%) was significantly correlated with greater symmetry in knee-extensor isometric (63%; r_s = 0.567, P = .002) and isokinetic (68%; r_s = 0.540, P = .003) strength, as well as greater cross-sectional area of the vastus medialis (78%; r_s = 0.519, P = .006) and vastus lateralis (82%; r_s = 0.752, P < .001). A higher International Knee Documentation Committee questionnaire score (82.2) was significantly correlated with greater symmetry in knee-extensor isokinetic strength (r_s = 0.379, P = .039).

CONCLUSIONS

Although deficits were observed in the surgical limb for all neuromuscular measures, greater symmetry in the size and strength of the quadriceps, rather than activation, was more strongly associated with physical performance after ACLR. Greater symmetry in strength was also more strongly associated with patient-reported function.

Cognitive-behavioral-based physical therapy to enhance return to sport after anterior cruciate ligament reconstruction: An open pilot study

OBJECTIVES

To describe feasibility, adherence, acceptability, and outcomes of a cognitive-behavioral-based physical therapy (CBPT-ACLR) intervention for improving postoperative recovery after anterior cruciate ligament reconstruction (ACLR).

DESIGN

Pilot study.

SETTING

Academic medical center.

PARTICIPANTS

Eight patients (mean age [SD] = 20.1 [2.6] years, 6 females) participated in a 7-session telephone-based CBPT-ACLR intervention beginning preoperatively and lasting 8 weeks after surgery.

MAIN OUTCOME MEASURES

At 6 months, patients completed Knee Injury and Osteoarthritis Outcome Score (KOOS) sports/recreation and quality of life (QOL) subscales, International Knee Documentation Committee (IKDC), Tampa Scale of Kinesiophobia (TSK), Pain Catastrophizing Scale (PCS), and Knee Self-Efficacy Scale (K-SES), return to sport (Subjective Patient Outcome for Return to Sports), and satisfaction. Minimal clinically important difference (MCID) was used for meaningful change.

RESULTS

Seven (88%) patients completed all sessions. Seven (88%) patients exceeded MCID on the TSK, 6 (75%) on the PCS, 5 (63%) on the KOOS sports/recreation subscale, 4 (50%) on the IKDC, and 3 (38%) on the KOOS QOL subscale. Three (38%) patients returned to their same sport at the same level of effort and performance. All patients were satisfied with their recovery.

CONCLUSIONS

A CBPT-ACLR program is feasible and acceptable for addressing psychological risk factors after ACLR.

Osteoarthritis and ACL Reconstruction-Myths and Risks

PURPOSE OF REVIEW

Anterior cruciate ligament (ACL) injury is one of the most common ligamentous injuries suffered by athletes participating in cutting sports. A common misperception is that ACL reconstruction can prevent osteoarthritis (OA). The goal of this paper is to review and discuss the contributing factors for the development of OA following ACL injury.

RECENT FINDINGS

There has been interesting new research related to ACL reconstruction. As understanding of knee biomechanics following ACL injury and reconstruction has changed over time, many surgeons have changed their surgical techniques to low anterior drilling to position their femoral tunnel in an attempt to place the ACL in a more anatomic position. Even with this change in the femoral tunnel position, 85% of knees following ACL reconstruction have abnormal tibial motion compared to contralateral non-injured knees. Studies have shown increases in inflammatory cytokines in the knee following ACL injury, and newer MRI sequences have allowed for earlier objective detection of degenerative changes to cartilage following injury. Recent studies have shown that injecting IL-1 receptor antagonist and corticosteroids can modulate the post-injury inflammatory cascade. ACL reconstruction does not prevent the development of OA but can improve knee kinematics and reduce secondary injury to the cartilage and meniscus. Advancements in imaging studies has allowed for earlier detection of degenerative changes in the knee, which has allowed researchers to study how new interventions can alter the course of degenerative change in the knee following ACL injury.

High Risk of Further Anterior Cruciate Ligament Injury in a 10-Year Follow-up Study of Anterior Cruciate Ligament-Reconstructed Soccer Players in the Swedish National Knee Ligament Registry

PURPOSE

To follow up on soccer players 10 years after a primary anterior cruciate ligament (ACL) reconstruction to find out how many players returned to play soccer, what influenced their decision, and if there are any differences in additional ACL injuries (graft failure and/or contralateral ACL injury) between those who returned to play and those who did not.

METHODS

The study cohort consists of 1661 soccer players from the Swedish National Knee Ligament Registry. A questionnaire was sent to each player regarding their return to play and additional knee injuries that may have occurred 10 years after their primary ACL. The results are based on the 684 responders. Data such as age, sex, surgical procedural data, associated injuries, patient-reported outcome measures, and additional knee surgeries were collected from the registry.

RESULTS

In this study, 51% returned to play soccer. For those who did not return to play, the primary reason was knee related (65.4% of the cases). The most common knee-related reasons for not returning were pain and/or instability (50%; n = 109), followed by fear of reinjury (32%; n = 69). Players who return to soccer have a significantly higher risk of additional ACL injury. Of the players who returned to play soccer, 28.7% (odds ratio [OR] 2.3, P < .001) had additional ACL injury, 9.7% (OR 2.9, P < .001) had a graft failure and 20.6% (OR 2.1, P < .001) had a contralateral ACL injury.

CONCLUSIONS

Players that return to soccer have a significantly higher risk of sustaining further ACL injury. Only half of the soccer players return to play after ACL reconstruction, and in two-thirds of those who did not return, the reason was knee related. The high risk of sustaining additional knee injury is of serious concern to the player's future knee health and should be considered when deciding on a return to play.

LEVEL OF EVIDENCE

Level III retrospective case-control study.

Editorial Commentary: Anterior Cruciate Ligament Injury and Reconstruction in Soccer Players: The Major Challenge Is Always Going for Our Goals!

Anterior cruciate ligament (ACL) injury affects a large number of athletes worldwide, and long-term rate of return to soccer is approximately 50% or less. ACL injury, which is noncontact in approximately 90% of cases, has a complex multifactorial etiology. Younger and higher-level players do better, and 10-year outcomes are superior to baseline. The role of genomics, hormonal status, neuromuscular deficiencies, anatomy, and the environment are all potential contributory risk factors that vary with respect to the individual, especially the female athlete. Furthermore, ACL injury results in a local and regional catabolic cascade and cytokine release, creating an intra-articular environment that is a homeostatic perfect storm and spectrum of scalable articular cartilage and meniscal injury. Once these complexities in the knee organ are defined and understood, the surgeon's early objectives are stabilization, repair, and restoration with full harmonization of biomechanics, neuromuscular control, and homeostasis. The goal is optimizing long-term outcomes, decreasing the rate of subsequent ACL injury, and preventing osteoarthritis.

Anterior cruciate ligament reconstruction using a double bundle hamstring autograft configuration in patients under 30 years

BACKGROUND

Anterior cruciate ligament reconstruction (ACLR) has a high incidence of re-tear in younger patients. Despite comparable functional outcomes, the incidence of re-tear using single and double bundle ACLR methods has not been well reported.

AIM

To hypothesize that double bundle hamstring ACLR has a lower graft rupture rate compared with single bundle hamstring ACLR grafts in young patients.

METHODS

One hundred and twelve patients < 30 years of age at the time of primary double bundle ACLR were eligible for study participation. 91 (81.3%) could be contacted, with a mean age of 20.4 years (range 13-29) and mean post-operative follow-up time of 59 mo (range 25-107). Telephone questionnaires evaluated the incidence (and timing) of subsequent re-tear and contralateral ACL tear, further surgeries, incidence and time to return to sport, and patient satisfaction.

RESULTS

Of the 91 patients, there were 6 (6.6%, 95%CI: 1.4-11.7) ACL graft re-ruptures, with a mean time to re-rupture of 28 mo (range 12-84). Fourteen patients (15.4%) experienced a contralateral ACL rupture and 14 patients (15.4%) required further surgery to their ipsilateral knee. fifty patients (54.9%) returned to pre-injury level of sport. Of those < 20 years (n = 45), 4 patients (8.9%, 95%CI: 0.4-17.3) experienced a re-rupture, with mean time to re-injury 15 mo (range 12-24). Comparative analysis with existing literature and revealed a non-significant Chi-squared statistic of 2.348 (P = 0.125).

CONCLUSION

A trend existed toward lower graft rupture rates in young patients undergoing double bundle ACLR utilizing a hamstring autograft, compared with rates reported after single bundle ACLR.

Return to Play and Long-term Participation in Pivoting Sports After Anterior Cruciate Ligament Reconstruction

BACKGROUND

Rupture of the anterior cruciate ligament (ACL) is a common and feared injury among athletes because of its potential effect on further sports participation. Reported rates of return to pivoting sports after ACL reconstruction (ACLR) vary in the literature, and the long-term consequences of returning have rarely been studied.

PURPOSE

To examine the rate and level of return to pivoting sports after ACLR, the duration of sports participation, and long-term consequences of returning to pivoting sports.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

All primary ACLRs with a bone-patellar tendon-bone autograft between 1987 and 1994 (N = 234) in athletes participating in team handball, basketball, or soccer before injury were selected from a single-center quality database. A long-term evaluation (median, 25 years; range, 22-30 years) was performed using a questionnaire focusing on return to pivoting sports, the duration of sports activity after surgery, later contralateral ACL injuries, revision surgery, and knee replacement surgery. Participants were stratified into 2 groups depending on the time between injury and surgery (early, <24 months; late, ≥24 months).

RESULTS

A total of 93% of patients (n = 217) responded to the questionnaire. Although 83% of patients returned to pivoting sports after early ACLR, only 53% returned to preinjury level. Similar return-to-sport rates were observed in males and females (P > .05), but males had longer sports careers (median, 10 years; range, 1-23 years) than females (median, 4 years; range, 1-25 years; P < .001). The incidence of contralateral ACL injuries was 28% among athletes who returned to sports versus 4% among athletes who did not return (P = .017) after early ACLR. The pooled reinjury rate after return to preinjury level of sports was 41% (30%, contralateral injuries; 11%, revision surgery). The incidence of contralateral ACL injuries was 32% among females versus 23% among males (P > .05) and, for revision surgery, was 12% among females versus 7% among males (P > .05) after returning to sports. Having a late ACLR was associated with an increased risk of knee replacement surgery (9% vs 3%; P = .049) when compared with having an early ACLR.

CONCLUSION

ACLR does not necessarily enable a return to preinjury sports participation. By returning to pivoting sports after ACLR, athletes are also facing a high risk of contralateral ACL injuries. Long-term evaluations in risk assessments after ACLR are important, as a significant number of subsequent ACL injuries occur later than the routine follow-up.

Trends in Recurrent Anterior Cruciate Ligament Injuries Differ From New Anterior Cruciate Ligament Injuries in College and High School Sports: 2009-2010 Through 2016-2017

Background:

Knee injuries are common and result in extended time missed from sports participation. Little is known regarding the comparative characteristics of recurrent versus first-time anterior cruciate ligament (ACL) injuries sustained during athletic events and how they are influenced by sex, sports participation level, and game-time features.

Purpose:

To evaluate the characteristics (sex, sports level, and game timing [ie, early vs late in the game]) of recurrent ACL injury in National Collegiate Athletic Association (NCAA) and high school athletes compared with first-time ACL injury.

Study Design:

Descriptive epidemiology study.

Methods:

Athletic trainers reported ACL injury occurrences and characteristics for collegiate athletes during the 2009-2010 through 2016-2017 academic years and for high school athletes during the 2011-2012 through 2013-2014 academic years. Logistic regression was used to estimate odds ratios (ORs) and 95% CIs for recurrent versus first-time ACL injury. The number of ACL injuries, proportions, and ORs were calculated by sex, competition level, and time in game played. Results were also classified according to injury mechanism: noncontact, overuse, or surface contact.

Results:

A total of 705 ACL injuries were reported, including 644 first-time injures and 61 recurrent injuries. When restricting to noncontact ACL injuries, 416 were reported (373 first-time injuries and 43 recurrent injuries). The odds of a recurrent versus new ACL injury in NCAA student-athletes were 4.6 times that of high school student-athletes (95% CI, 1.41-15.24; P = .01). When restricting to noncontact ACL injuries, the odds of a recurrent versus new ACL injury during postseason and preseason were 4.5 and 2.8 times that during the regular season, respectively. Athletes in limited-contact and noncontact sports had greater odds of a recurrent versus new ACL injury compared with athletes playing football and other contact and collision sports. There was no significant difference in the odds of a recurrent ACL injury by sex or time in game.

Conclusion:

Based on the current study, the odds of recurrent ACL injuries are associated with the level of competition but not associated with sex or timing of game play. Determinants of reinjury after primary ACL reconstruction will help advance care for young injured athletes who continue to participate in competitive sports.

Increased Radiographic Posterior Tibial Slope Is Associated With Subsequent Injury Following Revision Anterior Cruciate Ligament Reconstruction

Background:

Increased posterior tibial slope has been identified as a possible risk factor for injury to the anterior cruciate ligament (ACL) and has also been shown to be associated with ACL reconstruction graft failure. It is currently unknown whether increased posterior tibial slope is an additional risk factor for further injury in the context of revision ACL reconstruction.

Purpose:

To determine the relationship between posterior tibial slope and further ACL injury in patients who have already undergone revision ACL reconstruction.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

A total of 330 eligible patients who had undergone revision ACL reconstruction between January 2007 and December 2015 were identified from a clinical database. The slope of the medial and lateral tibial plateaus was measured on perioperative lateral radiographs by 2 fellowship-trained orthopaedic surgeons using a digital software application. The number of subsequent ACL injuries (graft rupture or a contralateral injury to the native ACL) was determined at a minimum follow-up of 2 years (range, 2-8 years). Tibial slope measurements were compared between patients who sustained further ACL injury to either knee and those who did not.

Results:

There were 50 patients who sustained a third ACL injury: 24 of these injuries were to the knee that underwent revision ACL reconstruction, and 26 were to the contralateral knee. Medial and lateral slope values were significantly greater for the third-injury group compared with the no–third injury group (medial, 7.5° vs 6.3° [P = .01]; lateral, 13.6° vs 11.9° [P = .001]).

Conclusion:

Increased posterior tibial slope, as measured from lateral knee radiographs, was associated with increased risk of graft rupture and contralateral ACL injury after revision ACL reconstruction. This is consistent with the concept that increased posterior slope, particularly of the lateral tibial plateau, is an important risk factor for recurrent ACL injury.

Case Study: Muscle Atrophy, Hypertrophy, and Energy Expenditure of a Premier League Soccer Player During Rehabilitation From Anterior Cruciate Ligament Injury

Maintaining muscle mass and function during rehabilitation from anterior cruciate ligament injury is complicated by the challenge of accurately prescribing daily energy intakes aligned to energy expenditure. Accordingly, we present a 38-week case study characterizing whole body and regional rates of muscle atrophy and hypertrophy (as inferred by assessments of fat-free mass from dual-energy X-ray absorptiometry) in a professional male soccer player from the English Premier League. In addition, in Week 6, we also quantified energy intake (via the remote food photographic method) and energy expenditure using the doubly labeled water method. Mean daily energy intake (CHO: 1.9-3.2, protein: 1.7-3.3, and fat: 1.4-2.7 g/kg) and energy expenditure were 2,765 ± 474 and 3,178 kcal/day, respectively. In accordance with an apparent energy deficit, total body mass decreased by 1.9 kg during Weeks 1-6 where fat-free mass loss in the injured and noninjured limb was 0.9 and 0.6 kg, respectively, yet, trunk fat-free mass increased by 0.7 kg. In Weeks 7-28, the athlete was advised to increase daily CHO intake (4-6 g/kg) to facilitate an increased daily energy intake. Throughout this period, total body mass increased by 3.6 kg (attributable to a 2.9 and 0.7 kg increase in fat free and fat mass, respectively). Our data suggest it may be advantageous to avoid excessive reductions in energy intake during the initial 6-8 weeks post anterior cruciate ligament surgery so as to limit muscle atrophy.

Superior 2-Year Functional Outcomes Among Young Female Athletes After ACL Reconstruction in 10 Return-to-Sport Training Sessions: Comparison of ACL-SPORTS Randomized Controlled Trial With Delaware-Oslo and MOON Cohorts

BACKGROUND

Outcomes after anterior cruciate ligament reconstruction (ACLR) are not uniformly good and are worse among young female athletes. Developing better rehabilitation and return-to-sport training programs and evaluating their outcomes are essential.

PURPOSE

(1) Test the effect of strength, agility, plyometric, and secondary prevention (SAPP) exercises with and without perturbation training (SAPP + PERT) on strength, hops, function, activity levels, and return-to-sport rates in young female athletes 1 and 2 years after ACLR and (2) compare 2-year functional outcomes and activity levels among young female athletes in the Anterior Cruciate Ligament Specialized Post-Operative Return-to-Sports (ACL-SPORTS) trial to homogeneous cohorts who completed criterion-based postoperative rehabilitation alone (Multicenter Orthopaedic Outcomes Network [MOON]) and in combination with extended preoperative rehabilitation (Delaware-Oslo).

STUDY DESIGN

Randomized controlled trial, Level of evidence, 1; and cohort study, Level of evidence, 3.

METHODS

A total of 40 level 1 and level 2 female athletes were enrolled after postoperative impairment resolution 3 to 9 months after primary ACLR. Participants were randomized to 10 SAPP or SAPP + PERT sessions and were tested 1 and 2 years after ACLR on quadriceps strength, hop tests, functional outcomes, and return-to-sport rates. Participants were then compared with homogeneous cohorts of young (<25 years) female athletes who completed criterion-based postoperative rehabilitation alone (MOON) and in combination with extended preoperative rehabilitation (Delaware-Oslo) on 2-year functional outcomes.

RESULTS

No significant or meaningful differences were found between SAPP and SAPP + PERT, so groups were collapsed for comparison with the other cohorts. At 2-year follow-up, ACL-SPORTS had the highest scores (P < .01) on the Marx activity rating scale (ACL-SPORTS, 13.5 ± 3.3; Delaware-Oslo, 12.5 ± 2.7; MOON, 10.6 ± 5.1); International Knee Documentation Committee Subjective Knee Evaluation Form (96 ± 7, 92 ± 9, and 84 ± 14, respectively); and Knee injury and Osteoarthritis Outcome Score (KOOS) subscales for Pain (98 ± 4, 94 ± 9, and 90 ± 10, respectively), Symptoms (94 ± 6, 90 ± 9, and 83 ± 14, respectively), Activities of Daily Living (100 ± 1, 99 ± 4, and 96 ± 7, respectively), Sports and Recreation (94 ± 8, 86 ± 15, and 82 ± 17, respectively), and Quality of Life (89 ± 14, 78 ± 18, and 76 ± 19, respectively). The Patient Acceptable Symptom State threshold on the KOOS-Sports and Recreation was achieved by 100% of the ACL-SPORTS cohort compared with 90% of Delaware-Oslo and 78% of MOON (P = .011).

CONCLUSION

Although perturbation training provided no added benefit, 10 sessions of return-to-sport training, compared with criterion-based postoperative rehabilitation alone, yielded statistically significant and clinically meaningfully higher 2-year functional outcomes among young, high-level female athletes after ACLR.

REGISTRATION

NCT01773317 (ClinicalTrials.gov identifier).

Multiplanar Loading of the Knee and Its Influence on Anterior Cruciate Ligament and Medial Collateral Ligament Strain During Simulated Landings and Noncontact Tears

BACKGROUND

Anterior cruciate ligament (ACL) tears and concomitant medial collateral ligament (MCL) injuries are known to occur during dynamic athletic tasks that place combinatorial frontal and transverse plane loads on the knee. A mechanical impact simulator that produces clinical presentation of ACL injury allows for the quantification of individual loading contributors leading to ACL failure.

PURPOSE/HYPOTHESIS

The objective was to delineate the relationship between knee abduction moment, anterior tibial shear, and internal tibial rotation applied at the knee and ACL strain during physiologically defined simulations of impact at a knee flexion angle representative of initial contact landing from a jump. The hypothesis tested was that before ACL failure, abduction moment would induce greater change in ACL strain during landing than either anterior shear or internal rotation.

STUDY DESIGN

Controlled laboratory study.

METHODS

Nineteen cadaveric specimens were subjected to simulated landings in the mechanical impact simulator. During simulations, external knee abduction moment, internal tibial rotation moment, and anterior tibial shear loads were derived from a previously analyzed in vivo cohort and applied to the knee in varying magnitudes with respect to injury risk classification. Implanted strain gauges were used to track knee ligament displacement throughout simulation. Kruskal-Wallis tests were used to assess strain differences among loading factors, with Wilcoxon each pair post hoc tests used to assess differences of magnitude within each loading.

RESULTS

Each loading factor significantly increased ACL strain (P < .005). Within factors, the high-risk magnitude of each factor significantly increased ACL strain relative to the baseline condition (P≤ .002). However, relative to knee abduction moment specifically, ACL strain increased with each increased risk magnitude (P≤ .015).

CONCLUSION

Increased risk levels of each load factor contributed to increased levels of ACL strain during a simulated jump landing. The behavior of increased strain between levels of increased risk loading was most prevalent for changes in knee abduction moment. This behavior was observed in the ACL and MCL.

CLINICAL RELEVANCE

Knee abduction moment may be the predominant precursor to ACL injury and concomitant MCL injury. As knee abduction occurs within the frontal plane, primary preventative focus should incorporate reduction of frontal plane knee loading in landing and cutting tasks, but secondary reduction of transverse plane loading could further increase intervention efficacy. Constraint of motion in these planes should restrict peak ACL strain magnitudes during athletic performance.

Horizontal jumping biomechanics among elite male handball players with and without anterior cruciate ligament reconstruction. An inertial sensor unit-based study

OBJECTIVES

Anterior cruciate ligament (ACL) tears are one of the most devastating injuries that any handball player can suffer during landing and pivoting actions. The aim of this study was to analyze the horizontal jumping biomechanics among male elite handball players with or without previous ACLR.

DESIGN

Descriptive study.

SETTING

Spanish elite male handball players.

PARTICIPANTS

Twenty-six male participants (6 ACL-R and 20 uninjured controls) were recruited.

MAIN OUTCOME MEASURES

Two horizontal hopping tasks were evaluated using an inertial sensor unit (ISU)-based technology to assess jumping biomechanics through a direct mechanics-based approach.

RESULTS

Non-significant differences were found in relation to any of the biomechanical or performance related analyzed variables.

CONCLUSIONS

Previously ACL-R elite male handball players who have returned to the top level of sports participation do not seem to possess lasting biomechanical and/or performance deficits 6 years after the original surgical ligament repair.

Return to sports and re-rupture rate following anterior cruciate ligament reconstruction in amateur sportsman: long-term outcomes

BACKGROUND

The aim of this study was to retrospectively evaluate patient satisfaction, the return-to-sport rate and activity level at a long-term follow-up in a large cohort of amateur sportsmen who underwent primary anterior cruciate ligament (ACL) reconstruction.

METHODS

A total of 218 patients who underwent primary ACL reconstruction between 2004 and 2011, were successfully recontacted and retrospectively reviewed at an average follow-up of 10.5 years (range, 7 to 14 years). All surgeries were performed by one single surgeon. All of them underwent primary ACL reconstruction with autogenous hamstring tendon grafts. Assessment included Knee Osteoarthritis Outcome Score (KOOS) score, International Knee Documentation Committee (IKDC) Subjective Knee Form, Tegner activity level. Patients were also asked what kind of injury they sustained (either direct or indirect trauma), what kind of sport they were performing when they got injured, at what time they did return to sports and which sport they practised before and after surgery.

RESULTS

Fourteen patients underwent re-rupture. In 11 cases, this was due to a new trauma occurring at an average time of 22.9 (SD 23.8) months following primary surgery. In 3 cases rupture occurred during rehabilitation period. Mean postoperative KOOS score was 88.5 (SD 8.5), while mean IKDC subjective score was 87.5 (SD 10.9). At the time of follow-up, most patients (214 subjects, 98%) were participating in sport. 156 subjects returned to pre-injury level (71.6%).

CONCLUSIONS

The study reported long-term favourable subjective outcomes in amateur sportsman following ACL reconstruction, with a low re-rupture rate and a high percentage of subjects (93.6%) returning to sports participation 12 months after surgery. Most patients (71.6%) were able to return to their preprimary level of activity and sport. Younger age at the time of ACL reconstruction positively affected return to sports; however, younger patients were significantly more likely than older patients to undergo re-rupture.

Identifying candidates for arthroscopic primary repair of the anterior cruciate ligament: A case-control study

INTRODUCTION

There has been a recent resurgence of interest in arthroscopic primary repair of proximal anterior cruciate ligament (ACL) tears. Patient selection is critical but not much is currently known on what predicts the possibility of repair. Goal of this study was therefore to assess predictive factors for the possibility of arthroscopic primary ACL repair.

METHODS

In this retrospective case-control study, all patients undergoing ACL surgery in a ten-year interval were included. Patients were treated with primary repair if there was a proximal tear and good tissue quality, or otherwise underwent ACL reconstruction. Collected data were age, gender, BMI, injury-to-surgery delay, injury mechanism and concomitant injuries. Receiver operating characteristic curves were used to find cutoff values, and all significant dependent variables were used in multivariate logistic analysis to assess independent predictors for the possibility of primary repair.

RESULTS

Three hundred sixty-one patients were included, of which in 158 patients (44%) primary repair was possible. Multivariate analysis (R² = 0.340, p < 0.001) showed that age > 35 years (Odds ratio [OR] 4.2, 95% CI 2.4-7.5,p < 0.001), surgery within 28 days (OR 3.3, 95% CI 1.9-5.7, p < 0.001), and BMI <26 (OR 1.9, 95% CI 1.1-3.3,p = 0.029) were predictive for the possibility of primary repair, and lateral meniscus injury presence decreased the likelihood of repair (OR 0.5, 95% CI 0.3-0.8, p = 0.008).

CONCLUSION

In this large cohort study, it was noted that 44% of patients had repairable ACL tears. Primary repair was more likely to be possible in older patients, patients with lower BMI and when surgery was performed within four weeks of injury.

The use of allograft tendons in primary ACL reconstruction

PURPOSE

Graft choice in primary anterior cruciate ligament (ACL) reconstruction remains controversial. The use of allograft has risen exponentially in recent years with the attraction of absent donor site morbidity, reduced surgical time and reliable graft size. However, the published evidence examining their clinical effectiveness over autograft tendons has been unclear. The aim of this paper is to provide a current review of the clinical evidence available to help guide surgeons through the decision-making process for the use of allografts in primary ACL reconstruction.

METHODS

The literature in relation to allograft healing, storage, sterilisation, differences in surgical technique and rehabilitation have been reviewed in addition to recent comparative studies and all clinical systematic reviews and meta-analyses.

RESULTS

Early reviews have indicated a higher risk of failure with allografts due to association with irradiation for sterilisation and where rehabilitation programs and post-operative loading may ignore the slower incorporation of allografts. More recent analysis indicates a similar low failure rate for allograft and autograft methods of reconstruction when using non-irradiated allografts that have not undergone chemically processing and where rehabilitation has been slower. However, inferior outcomes with allografts have been reported in young (< 25 years) highly active patients, and also when irradiated or chemically processed grafts are used.

CONCLUSION

When considering use of allografts in primary ACL reconstruction, use of irradiation, chemical processing and rehabilitation programs suited to autograft are important negative factors. Allografts, when used for primary ACL reconstruction, should be fresh frozen and non-irradiated. Quantification of the risk of use of allograft in the young requires further evaluation.

LEVELS OF EVIDENCE

III.

Comparison of Short-term Biodex Results After Anatomic Anterior Cruciate Ligament Reconstruction Among 3 Autografts

Background:

An individualized approach to anterior cruciate ligament reconstruction (ACLR) typically includes criteria-based postoperative rehabilitation. However, recent literature has suggested residual quadriceps weakness up to 12 months after ACLR, especially with a quadriceps tendon (QT) autograft.

Hypothesis:

The QT would have poorer quadriceps strength symmetry at 5 to 8 months compared with the hamstring tendon (HS) and patellar tendon (BPTB), but there would be no significant difference at 9 to 15 months among all 3 groups.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Patients who underwent anatomic primary ACLR with an autograft were reviewed retrospectively. Isometric quadriceps and hamstring strength measurements were obtained clinically at 5 to 8 months and 9 to 15 months postoperatively. Return-to-running and return-to-play criteria included greater than 80% and 90% quadriceps strength symmetry, respectively.

Results:

A total of 73 patients with 5- to 8-month follow-up were identified, and 52 patients had 9- to 15-month data. The QT group had a significantly lower quadriceps index at 5 to 8 months (69.5 ± 17.4) compared with the BPTB (82.8 ± 14.6; P = .014) and the HS (86.0 ± 18.6; P = .001) groups. More patients with an BPTB autograft met criteria for return to running and return to play (60% and 47%, respectively) compared with the QT group (26% and 13%, respectively) at 5 to 8 months. Given the sample sizes available, we observed no significant difference in the quadriceps index and return-to-play and return-to-running criteria at 9 to 15 months among those undergoing ACLR with a QT, BPTB, or HS graft.

Conclusion:

Patients undergoing ACLR with a QT graft demonstrated clinically meaningful quadriceps asymmetry at 5 to 8 months and 9 to 15 months postoperatively. Additionally, fewer patients in the QT group met criteria for return to play and running at 5 to 8 months than the BPTB and HS groups. These data suggest that a longer time to return to play and specific rehabilitation protocols that emphasize quadriceps strengthening may be necessary because of residual quadriceps weakness after ACLR with a QT graft.

How Much Do Psychological Factors Affect Lack of Return to Play After Anterior Cruciate Ligament Reconstruction? A Systematic Review

Background:

Variables affecting return to sport after anterior cruciate ligament reconstruction (ACLR) are multifactorial. The nonphysical factors germane to successful return to play (RTP) are being increasingly recognized.

Purpose:

To (1) evaluate the available evidence base for psychological factors relating to RTP after ACLR, (2) identify psychological factors affecting RTP after ACLR, and (3) understand currently available metrics used to assess psychological RTP readiness.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

A review of the MEDLINE database was performed for studies reporting RTP after ACLR. Studies reporting on the psychological determinants of RTP were included. Demographic, methodological, and psychometric properties of the included studies were extracted. Weighted analysis was performed after patients were pooled across included studies.

Results:

Of 999 studies identified in the initial search, 28 (2.8%) studies, comprising 2918 patients, were included; 19 studies (n = 2175 patients) reported RTP rates. The mean time for RTP was 17.2 months. There was a 63.4% rate of RTP, and 36.6% of patients returning to sport were not able to perform at their prior level of play. Of the 795 patients who did not achieve RTP, 514 (64.7%) cited a psychological reason for not returning. Fear of reinjury was the most common reason (n = 394; 76.7%); other psychological factors included lack of confidence in the treated knee (n = 76; 14.8%), depression (n = 29; 5.6%), and lack of interest/motivation (n = 13; 2.5%). The Tampa Scale for Kinesiophobia, the Hospital Anxiety and Depression Scale, the ACL–Return to Sport after Injury scale, and the Knee Self-Efficacy Scale were reported measures for assessing the influence of psychology on RTP.

Conclusion:

Psychological factors play an important role in RTP after ACLR. Among studies evaluating the impact of psychology on RTP, there was a delay in returning as well as lower RTP rates compared with the previously reported normative literature. Fear of reinjury was the most commonly reported impediment to RTP. The psychosocial measures identified in this review may have a role in RTP protocols for assessing mental resiliency; however, their roles need to be further investigated and validated in patients who have undergone ACLR.

Sex Differences in Common Sports-Related Injuries

Sex plays a role in mediating different susceptibilities and outcomes of disease and injury. Sports injuries are included in this phenomenon, as recent research demonstrates that males and females show differences in incidences of varying injuries, presentations of injury, and treatment outcomes. Incidence of certain sports injuries like anterior cruciate ligament injury or patellofemoral pain syndrome may vary widely between male and female athletes, with female athletes being more susceptible to anterior cruciate ligament injury and patellofemoral pain syndrome. Treatment outcomes for males and females may also vary widely. For example, males have a higher risk of recurrent shoulder instability compared with females. These variances among incidence and outcome following certain injuries highlight the necessity of understanding these differences to provide quality care. It is especially important for the school nurse to be aware of these sex differences as they are well positioned to make youth athletes and their families aware of the varying injury susceptibilities among them.

Shear wave elastography of the healing human patellar tendon following ACL reconstruction

PURPOSE

Anterior cruciate ligament (ACL) ruptures are common and are frequently reconstructed using a patellar tendon (PT) autograft. Unfortunately, the time course of PT healing after ACL reconstruction is not particularly well understood. Thus, the primary objective of this study was to use shear wave elastography (SWE) to evaluate the extent to which shear wave speed (SWS) is associated with time after ACL reconstruction.

METHODS

Longitudinal SWE images were acquired from lateral, central, and medial regions of the PT from two groups: 30 patients who had undergone ACL reconstruction with a PT autograft within the preceding 40 months, and 30 age-matched asymptomatic control subjects. SWE images were acquired at 20° and 90° of passive flexion from both knees. In each subject group, statistical analyses assessed changes in mean SWS with time post-surgery, as well as differences in mean SWS between PT regions and limbs.

RESULTS

In the ACL reconstruction patients, mean SWS increased with time post-surgery in the lateral region of the involved knee (p = 0.025) and decreased with time post-surgery in the central region of the contralateral knee (p = 0.022).

CONCLUSION

The findings suggest that there is an association between the mechanical properties of the PT and time post-surgery in both the involved and contralateral limbs after ACL reconstruction. These changes are likely due to maturation of the donor site tissue and changes in gait/loading patterns following ACL rupture and reconstruction.

LEVEL OF EVIDENCE

Level II - Prospective Cohort.

Partial meniscectomy adversely affects return-to-sport outcome after anatomical double-bundle anterior cruciate ligament reconstruction

PURPOSE

The purposes of this study were to determine whether the partial meniscectomy combined with ACL reconstruction affect the postoperative return-to-sport and to identify if partial meniscectomy has an influence on the graft failure following an anatomical double-bundle ACL reconstruction case.

METHODS

A retrospective cohort study including 426 primary double bundle ACL reconstruction cases. There were 206 males and 220 females, median age of 28.4 years, median BMI of 23.0, median preinjury Tegner score of 7.0 and median follow-up period after surgery of 24.0 months. Patients with less than 12 months of follow-up, revision surgery, multi-ligaments injury, previous contralateral knee ligaments injury and postoperative infection cases were excluded. Furthermore, patients who had meniscal repair were excluded in order to compare the outcomes between patients who had intact menisci and those who underwent partial meniscectomy. There were 227 patients with intact menisci (group A) and 199 patients with partial meniscectomy (group B). The median age was younger and the preoperative Tegner score was higher in group A. The patients in group B were subcategorized as the site of partial meniscectomy, including medial (group C), lateral (group D) and bicompartmental (group E) meniscectomy. There were 74, 94, and 31 patients in group C, D, and E, respectively. Return-to-sport (running and sport phase) and graft failure were included in our primary outcomes, and functional outcome as Lysholm knee scores was included in secondary outcome.

RESULTS

The rate of return to running phase and sport phase were 91% (387/426) and 76% (303/399), the mean time taken to return to running and sport phase were 5.7 months and 11.1 months, respectively. There was significant difference in the returning to sport phase between group A and B (p = 0.01), and between group A and D/E subgroups (p = 0.007). There were fourteen graft failures (3.5%) in total. In addition, 9 and 5 graft failures in group A and B, respectively. Of the 5 graft failures in group B, 2 and 3 graft failures in group C and D, respectively. There was no significant difference of the graft failure ratio among the groups.

CONCLUSION

Our study demonstrates that partial meniscectomy has an adverse effect on the return to sport phase following the anatomical double-bundle ACL reconstruction. Therefore, greater postoperative care would be needed to return to sport with partial meniscectomy in ACL reconstruction cases. On the contrary, partial meniscectomy is not considered to be the risk factor for graft failure at short-term follow-up.

LEVEL OF EVIDENCE

Case-control study, Level III.

Factors influencing return to play following conservatively treated ankle sprain: a systematic review

BACKGROUND

Ankle sprain is a very common injury, yet uncertainty exists in what is appropriate time to return to play (RTP). Such guidance may inform treatment pathways and effective practice.

OBJECTIVES

To determine if consensus exist about potential influencing factors for time to RTP in conservatively treated ankle sprain.

METHODS

We searched AMED, CINAHL Plus, Cochrane library, EMBASE, MEDLINE (EBSCO), SPOERDiscus, PsycINFO, PEDro, Scopus, unpublished literature and ongoing trials and Google Scholar from inception until April 2017. The quality of the eligible papers was assessed using the Downs and Black tool for randomized controlled trials (RCTs) and Critical Appraisal Skills Program (CASP) for observational studies.

RESULTS

The initial search identified 1885 articles. After screening, 14 articles were included. Of these, 11 were RCTs and 3 were prospective observational studies. Individual treatment methods that resulted in a shorter time to RTP were functional treatment, compression stockings, anteroposterior joint mobilization, hyaluronic acid injection (HA), Jump Stretch Flex Band programme (JSFB) and diclofenac medication. Prognostic factors for determining time to RTP in the included prospective observational studies were measures of Global function, SF 36PF, athlete's ambulation status, weight-bearing activity scores and self-reported athletic ability.

CONCLUSION

To our knowledge, this is the first review to report influencing factors for time to RTP following conservatively treated ankle sprain. Findings from this review identified factors that influence time to RTP. However, caution should be taken in generalizing these results due to the heterogeneity of studies and inability to clearly define and list the criteria for safe RTP. The inclusion of factors such as age, sex, BMI, level of sport, injury related factors in future studies might help to understand the course of injury and therefore assist in constructing safer criteria.

The relationship between frontal plane trunk control during landing and lower extremity muscle strength in young athletes after anterior cruciate ligament reconstruction

BACKGROUND

Lower extremity landing asymmetries are common and associated with strength deficits after anterior cruciate ligament reconstruction. However, less is known regarding trunk control during landing. This study's hypotheses were that frontal plane trunk excursion during single-leg landing would be greater in young athletes after anterior cruciate ligament reconstruction compared to controls and would be associated with strength deficits.

METHODS

Participants included 130 young athletes recently cleared for return-to-sport following anterior cruciate ligament reconstruction and 56 uninjured young athletes. Frontal plane trunk excursion was quantified using three-dimensional motion analysis during a single-leg landing task. Quadriceps and hip abduction strength were measured using an isokinetic dynamometer. Frontal plane trunk excursion was compared between the anterior cruciate ligament reconstruction and control groups and among quadriceps strength subgroups using independent t-tests and one-way analysis of variance. Linear regression examined the association between frontal plane trunk excursion and strength measures in the anterior cruciate ligament reconstruction group.

FINDINGS

The anterior cruciate ligament reconstruction group demonstrated greater frontal plane trunk excursion compared to controls. The low-quadriceps group demonstrated greater frontal plane trunk excursion compared to both the high-quadriceps and control groups. Additionally, the high-quadriceps group demonstrated greater frontal plane trunk excursion compared to controls. In the anterior cruciate ligament reconstruction group, lower quadriceps and hip abduction strength were weakly associated with greater frontal plane trunk excursion.

INTERPRETATION

Young athletes at time of return-to-sport after anterior cruciate ligament reconstruction demonstrated increased frontal plane trunk excursion during single-leg landing. Additionally, increased frontal plane trunk excursion was weakly associated with strength deficits.

Sex differences in sagittal plane control emerge during adolescent growth: a prospective investigation

PURPOSE

Females athletes have a higher incidence of non-contact knee joint injuries compared to their male counterparts. This may be attributable to sex-specific differences in neuromuscular control, which arise during the pubertal growth spurt. The purpose of this longitudinal study was to assess the development of landing kinematics of adolescent male and female athletes during the adolescent growth-spurt.

METHODS

One hundred and eighty-four adolescent athletes (55% male, 45% female; mean age = 13 ± 0.3 years) participated. Testing was undertaken at baseline and then repeated at 6, 12, 18 and 24 months. Participants performed three drop vertical jump (DVJ) trials from a 31 cm box. Frontal and sagittal plane knee joint angles were recorded. The average measurement of the three jumps was used for analysis at each time point. To assess maturation status, participants were categorised according to their age from peak height velocity at baseline. Pre-initial contact knee flexion (pre-IC), peak knee flexion and knee valgus displacement were the dependant variables. The categorical independent variables were sex (male versus female) and time.

RESULTS

There was a significant sex*time interaction for pre-IC knee flexion, with males increasing knee flexion with time to a greater extent than females. There was no significant sex*time interaction for knee valgus displacement; although females displayed greater knee valgus displacement across all time points.

CONCLUSIONS

Adolescent male and female athletes display differing kinematic profiles across growth and development. This has clinical relevance for emphasising increased knee flexion, as well as decreasing abnormal frontal plane displacement in injury prevention programmes for adolescent females.

LEVEL OF EVIDENCE

II.

Outcome of isolated posterior cruciate ligament reconstruction at mean 6.3-year follow up: a consecutive case series

OBJECTIVES

There is a paucity of reporting on surgical outcomes of isolated posterior cruciate ligament reconstruction (PCLR). We hypothesize that isolated PCL injuries failing nonoperative treatment achieve good outcomes and are able to return to sport following PCLR.

METHODS

A retrospective analysis was performed to identify patients with isolated PCL injuries that underwent reconstruction between 2001 and 2014. Patients with multi-ligamentous injury or another concomitant knee pathology were excluded. Medical records were reviewed for demographic, clinical and operative data. Patients were contacted for administration of a telephone-based questionnaire which included the International Knee Documentation Committee (IKDC) Subjective Knee Evaluation form, Lysholm-Tegner scales, Marx activity scale (MAS), return to sport status, and patient satisfaction instruments.

RESULTS

A total of 15 isolated PCL reconstructions in 14 patients with a mean age of 27.5 years (range 17-43) met the study inclusion criteria; mean follow up was 6.3 years (range 1.4-15.2). Pre-operatively, the primary complaint was knee instability in all patients; on physical examination, lack of a firm end point during posterior drawer testing was found in 93% (14/15) of the knees. In total, 12 of 15 knees underwent transtibial, single-bundle PCLR and three of 15 underwent tibial inlay, double bundle PCLR. Graft types included: quadriceps autograft (7/15), Achilles allograft (6/15), and hamstring autograft (2/15). There were no graft failures in our patient cohort. At most recent follow up the mean scores respectively on the IKDC form, Lysholm-Tegner scales and MAS were (standard deviation): 77.3 (16.5), 83.1 (17.9), 6.13 (2.6), and 7.1 (6.0). All fourteen patients were athletes prior to their injury and 79% (11/14) returned to sport and overall patient satisfaction was 9.2/10.

CONCLUSIONS

Isolated PCLR provides good outcomes at mean medium-term follow up with restoration of function, high rate of return to sport and overall patient satisfaction.

Editorial Commentary: Anatomy of the Anterolateral Ligament of the Knee-The Science of Looking for Bigfoot

The anterolateral ligament of the knee continues to create a spirited debate within orthopaedics. This can be traced as far back as 1879, when Segond initially described a "pearly, resistant, fibrous band" of the anterolateral aspect of the knee. More recently, much orthopaedic research has been aimed at not only the clinical significance-but defining its very existence. At times, it seems akin to a modern-day search for Bigfoot-some see it, some do not. The authors of this commentary are becoming less skeptical of the anterolateral ligament's existence but remain in search of its surgical significance.

A research update on the state of play for return to sport after anterior cruciate ligament reconstruction

Most athletes who undergo anterior cruciate ligament (ACL) reconstruction surgery plan to return to some level of sporting activity. However, rates of return to pre-injury sport are often less than might be expected and many factors influence whether individuals return to sport after this surgery. They include surgical and rehabilitation factors as well as social, psychological and demographic characteristics. The fate of the younger athlete who sustains an ACL injury is a topic that has received recent attention due to accumulating evidence that younger athletes are at considerable risk for not only one, but multiple ACL injuries. Little is known about how to determine when it is safe to return to sport following ACL reconstruction or how to predict whether an athlete will be able to successfully return. The notion that a set of return to sport criteria can be applied to reduce the risk of further injury has become popular with many different criteria proposed. Another risk of returning to sport following ACL reconstruction is that of sustaining injury to the menisci or articular surfaces, which may in turn increase the risk of developing osteoarthritis. Although there is some evidence that ACL reconstruction reduces the risk of osteoarthritis there is stronger evidence that it does little to protect the knee from long term degeneration. Therefore, it should be recognized that return to sport following ACL reconstruction is associated with a risk of further injury and potential development of osteoarthritis.Level of evidence: V.

Young age and high BMI are predictors of early revision surgery after primary anterior cruciate ligament reconstruction: a cohort study from the Swedish and Norwegian knee ligament registries based on 30,747 patients

PURPOSE

To analyse patient-related risk factors for 2-year ACL revision after primary reconstruction. The hypothesis was that younger athletes would have a higher incidence of an early ACL revision.

METHODS

This prospective cohort study was based on data from the Norwegian and Swedish National Knee Ligament Registries and included patients who underwent primary ACL reconstruction from 2004 to 2014. The primary end-point was the 2-year incidence of ACL revision. The impact of activity at the time of injury, patient sex, age, height, weight, BMI, and tobacco usage on the incidence of early ACL revision were described by relative risks (RR) with 95% confidence intervals (CI).

RESULTS

A total of 58,692 patients were evaluated for eligibility and 30,591 patients were included in the study. The mean incidence of ACL revision within 2 years was 2.82% (95% CI 2.64-3.02%). Young age (13-19) was associated with an increased risk of early ACL revision (males RR = 1.54 [95% CI 1.27-1.86] p < 0.001 and females RR = 1.58 [95% CI 1.28-1.96] p < 0.001). Females over 1 SD in weight ran an increased risk of early ACL revision (RR = 1.82, [95% CI 1.15-2.88] p = 0.0099). Individuals with a BMI of over 25 ran an increased risk of early ACL revision (males: RR = 1.78, [95% CI 1.38-2.30] p < 0.001 and females: RR = 1.84, [95% CI 1.29-2.63] p = 0.008).

CONCLUSION

Young age, a BMI over 25, and overweight females were risk factors for an early ACL revision.

LEVEL OF EVIDENCE

II.

The negative impact of anterior cruciate ligament reconstruction in professional male footballers

BACKGROUND

Soccer is one of the most common international sports in which ACL injuries occur, with previous studies reporting high return-to-play rates following ACL reconstruction (ACLR). Return-to-play analysis fails to take into consideration how effective a player remains once returning to competition. The aims of this study are to provide a large-scale international analysis of return-to-play and player performance statistics among professional soccer athletes following ACLR.

METHODS

Using publicly available sources, professional soccer athletes who have undergone ACLR between the 1996 and 2015 seasons were identified. Player metrics including statistical performance, recovery time, and return-to-play rates were analyzed both before and after reconstruction. Furthermore, player performance statistics during each of three consecutive seasons post-ACLR were compared.

RESULTS

A total of 176 athletes who underwent ACLR were included in this study. The return-to-play rate was 93.2% (164 athletes). Cumulative post-surgical statistical analysis of ACLR players demonstrated fewer games/season, minutes/season, minutes/game, goals/season, and more fouls/season following ACLR (p < 0.04). Analysis of player performance statistics suggests that athletes do not return to their baseline number of games/season and minutes/game until two and three seasons post-ACLR, respectively. At three seasons post-ACLR, athletes are still starting fewer games/season and scoring fewer goals/90 min (p < 0.04).

CONCLUSION

Return-to-play rate is high following ACLR; however, athletes exhibit poorer statistical performance, especially in the first few seasons upon return. Our data shows that athletes continue to start fewer games/season and score fewer goals/90 min at three seasons post-ACLR.

Female Soccer Players With Anterior Cruciate Ligament Reconstruction Have a Higher Risk of New Knee Injuries and Quit Soccer to a Higher Degree Than Knee-Healthy Controls

BACKGROUND

Many patients with anterior cruciate ligament (ACL) reconstruction who return to sport suffer new ACL injuries or quit sports soon after returning.

PURPOSE

To prospectively follow a cohort of female soccer players with primary unilateral ACL reconstruction and matched knee-healthy controls from the same soccer teams to compare (1) the rate of new traumatic and nontraumatic knee injuries and other injuries, (2) the proportion of players who quit soccer, and (3) player-reported activity level and satisfaction with activity level and knee function.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A total of 117 active female soccer players (mean ± SD age, 19.9 ± 2.5 years) 18.9 ± 8.7 months after ACL reconstruction and 119 knee-healthy female soccer players (19.5 ± 2.5 years) matched from the same teams were prospectively followed for 2 years for new knee injuries, other injuries, soccer playing level, activity level according to the Tegner Activity Scale, and satisfaction with activity level and knee function.

RESULTS

Players with ACL reconstruction had a higher rate of new ACL injuries (n = 29 vs 8; 19 vs 4 per 100 player years; rate ratio [RR], 4.82; 95% CI, 2.20-10.54; P < .001), other traumatic knee injuries (29 vs 16 per 100 player years; RR, 1.84; 95% CI, 1.16-2.93; P < .01), and nontraumatic knee injuries (33 vs 9 per 100 player years; RR, 3.62; 95% CI, 2.11-6.21; P < .001) as compared with controls. There was no difference in the rate of other (not knee) injuries (43 vs 48 per 100 player years; RR, 0.90; 95% CI, 0.65-1.23; P = .494). During the 2-year follow-up, 72 (62%) players with ACL reconstruction quit soccer, as opposed to 43 (36%) controls ( P = .001). The median Tegner Activity Scale score decreased in both groups ( P < .001) but more for the ACL-reconstructed group ( P < .015).

CONCLUSION

Female soccer players with ACL reconstruction had nearly a 5-fold-higher rate of new ACL injuries and a 2- to 4-fold-higher rate of other new knee injuries, quit soccer to a higher degree, and reduced their activity level to a greater extent as compared with knee-healthy controls.

Return to sport and re-tears after anterior cruciate ligament reconstruction in children and adolescents

BACKGROUND

The primary objective of this study was to determine the time to and level of return to sports after anterior cruciate ligament (ACL) reconstruction in children and adolescents. The secondary objectives were to evaluate the risk of early ACL re-tear after return to sports and the risk of ACL tear in the contralateral knee.

HYPOTHESIS

The time to return to sports in young patients is considerably longer than in adults.

METHODS

A prospective multicentre study was conducted at 12 centres specialised in knee ligament surgery, in children and adolescents younger than 18 years, between 1 January 2015 and 31 October 2015. The patients were divided into a paediatric group with open physes and a skeletally mature group with closed physes. We recorded the time to return to sport, the type of sport resumed, and the occurrence of early re-tears on the same side. A poor outcome was defined as a re-tear or an objective IKDC score of C or D. A contralateral ACL tear was not considered a poor outcome.

RESULTS

Of 278 included patients, 100 had open physes and 178 closed physes. In the open physes group, return to running occurred after 10.4±4.7 months, return to pivoting/contact sport training after 13.1±3.9 months, and return to pivoting/contact sport competitions after 13.8±3.8 months. Of the 100 patients, 80% returned to the same sport and 63.5% to pivoting/contact sport competitions. Re-tears occurred in 9% of patients, after 11.8±4.1 months, and contralateral tears in 6% of patients, after 17.2±4.4 months. In all, 19.4% of patients had a poor outcome, including 10.4% with an IKDC score of C or D and 9% with re-tears. In the group with closed physes, return to running occurred after 8.8±5.1 months, return to pivoting/contact sport training after 11.7±4.7 months, and return to pivoting/contact sport competitions after 12.3±4.2 months. Of the 178 patients, 76.9% returned to the same sport and 55.6% to pivoting/contact sport competitions. The re-tear rate was only 2.8% and the contralateral tear rate 5%. In all, 14.7% of patients had poor outcome, including 11.9% with an IKDC score of C or D and 2.8% with re-tears. No risk factors for re-tears were identified; the quadruple-bundle semitendinosus technique showed a non-significant association with re-tears.

CONCLUSION

In young children, the return to sport time after ACL reconstruction is considerably longer than 1 year and the return to competitions occurs later and is more difficult. The results of this study indicate that reservations are in order when informing the family about return to sports prospects after ACL reconstruction. The return to pivoting/contact sport competitions should not be allowed until 14 months after surgery in young skeletally immature patients, and the risk of re-injury is high within the first 2 years.

LEVEL OF EVIDENCE

IV, retrospective study.

Athletic Trainers' Effect on Population Health: Improving Access to and Quality of Care

CONTEXT

The scope of athletic training practice combined with the magnitude of scholastic athletic injuries means that the scholastic athletic trainer (AT) is uniquely positioned to positively affect the overall health care of this population. The AT is equipped to serve in the prevention and primary management of injuries and return to activity of scholastic athletes. However, to optimize the musculoskeletal health of all athletes within a given setting, the gaps in clinical care must be continuously evaluated. Quality improvement (QI) approaches are often used to establish a framework for delivering care that promotes the best health status of the targeted population.

OBJECTIVE

To describe the creation, implementation, and early results of a QI initiative aimed at advancing the health of the scholastic athletes served in the Greenville County, South Carolina, school district.

DESIGN

Cohort study.

PATIENTS OR OTHER PARTICIPANTS

A total of 49 793 athletes.

MAIN OUTCOME MEASURE(S)

The QI framework consisted of a process that documented the magnitude of athletic injuries, established risk factors for injury, defined intervention steps for at-risk athletes, and evaluated the QI process before and after implementation. The results were regularly reported to participating stakeholders, including ATs, athletic directors, coaches, parents, and athletes.

RESULTS

After the QI process, injury rates decreased (absolute risk difference between the 2011-2012 and 2016-2017 academic years = 22%) and resources were more strategically allocated, which resulted in a decrease in health care costs of more than 50%.

CONCLUSIONS

Collectively, the QI framework as described provides a systematic process for empowering the AT as the foundation of the scholastic sports medicine team.

KOOS-JR Demonstrates Psychometric Limitations in Measuring Knee Health in Individuals After ACL Reconstruction

BACKGROUND

Measurement properties of the short form of the Knee injury and Osteoarthritis Outcome Score (KOOS-JR) are not established in individuals after anterior cruciate ligament reconstruction (ACLR). The purpose of this study was to determine the extent to which the KOOS-JR measures the construct of knee health in individuals post-ACLR using Rasch analysis.

HYPOTHESIS

The KOOS-JR will fit the Rasch model, but significant ceiling effects will be present.

STUDY DESIGN

Cross-sectional study.

LEVEL OF EVIDENCE

Level 3.

METHODS

Rasch analysis of the KOOS-JR from 166 individuals 10 months post-ACLR was conducted. Unidimensionality, a key criterion of the Rasch model, was evaluated using confirmatory factor analysis. Model fit of the rating scale, items, and persons were evaluated. Mean square fit statistics ≥1.6 and standardized z-scores ≥2.0 were indicative of person or item misfit. Additionally, reliability indicators including person reliability and separation indices were examined.

RESULTS

The KOOS-JR fit the criteria of unidimensionality. All items demonstrated model fit; however, ceiling effects were noted (n = 36; 22%). Person reliability was low (0.47). Calculation of person strata revealed that the KOOS-JR did not separate participants into more than 1 stratum. The mean person measure was 3.56 logits higher than the mean item measure, indicating that this sample is skewed toward increased knee health.

CONCLUSION

Although the KOOS-JR represented a unidimensional construct with items and persons fitting the Rasch model, several limitations were noted: ceiling effects, low person reliability, and poor person differentiation. Ceiling effects indicate that many individuals in this sample experienced better knee health than the KOOS-JR items were able to measure.

CLINICAL RELEVANCE

Evaluating the measurement properties of the KOOS-JR is necessary to determine its clinical value in sports medicine. In later stages after ACLR recovery, administration of the KOOS-JR may not be adequate.

Return to Sport-Specific Performance After Primary Anterior Cruciate Ligament Reconstruction: A Systematic Review

BACKGROUND

Physicians counseling athletes on the prognosis of sport-specific performance outcomes after anterior cruciate ligament reconstruction (ACLR) depend on the published literature. However, critical appraisal of the validity and biases in these studies is required to understand how ACLR affects an athlete's ability to return to sport, the athlete's sport-specific performance, and his or her ability to achieve preinjury levels of performance.

PURPOSE

This review identifies the published prognostic studies evaluating sport-specific performance outcomes after ACLR. A risk of bias assessment and summaries of return to sport and career longevity results are provided for each included study.

STUDY DESIGN

Systematic review.

METHODS

Electronic databases (Ovid MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, and PUBMED) were searched via a defined search strategy with no limits, to identify relevant studies for inclusion in the review. A priori defined eligibility criteria included studies measuring sport-specific performance within an athlete's sport, before and after primary ACLR. Reference lists of eligible studies were hand-searched for additional relevant studies. Data extraction was performed by use of a standardized spreadsheet. Each included study was assessed by use of 6 bias domains of the Quality in Prognosis Studies tool to critically appraise study participation, study attrition, prognostic factors, outcome measurement, confounders, and statistical analysis and reporting. Two authors independently performed each stage of the review and reached consensus through discussion.

RESULTS

Fifteen pertinent prognostic studies evaluated sport-specific performance outcomes and/or return to play after ACLR for athletes participating in competitive soccer, football, ice hockey, basketball, Alpine ski, X-Games ski and snowboarding, and baseball. Twelve of these studies were considered to have a high level of bias.

CONCLUSION

This review demonstrated that most high-performance or professional athletes returned to their preinjury level of sport after ACLR. The bulk of evidence suggests there was a measurable decrease in performance statistics, although this is highly sport-specific. A paucity of literature is available that addresses sport-specific performance in athletes after ACLR. This review has determined that the available literature is highly biased and must be read with caution.

CLINICAL RELEVANCE

By better understanding the validity and biases in the published literature, physicians can provide more informed prognoses about return to sport-specific performance after ACLR while considering risk factors relevant to their patients.

REGISTRATION

CRD42016046709 (International Prospective Register of Systematic Reviews, https://www.crd.york.ac.uk/prospero/ ).

Sex differences in physical activity engagement after ACL reconstruction

OBJECTIVES

To investigate the effects of sex as an effect modifier of objectively measured moderate-to-vigorous physical activity (MVPA) in individuals following ACLR and healthy controls.

DESIGN

Cross-sectional research study.

SETTING

University community.

PARTICIPANTS

59 participants (42.4% male) with a history of ACLR and 55 healthy control participants (40.0% male).

MAIN OUTCOME MEASURES

Participants were outfitted with an ActiGraph wGT3X-BT accelerometer for a period of 7 days to assess MVPA. Weekly time engaged in MVPA (in bouts≥ 10 min), % of total time engaged in MVPA, and odds of meeting national physical activity guidelines (MVPA≥ 150 min/wk) were compared between males and females with a history of ACLR and healthy controls.

RESULTS

There were significant sex X group interactions for weekly MVPA (p = 0.02) and % total time in MVPA (p = 0.01). The odds of a female ACLR participant meeting national physical activity guidelines were significantly worse (X² = 4.18, OR = 2.54, CI₉₅ = 1.03-6.27) when compared to participants without ACLR.

CONCLUSIONS

Female participants with ACLR were found to be less active than healthy control participants and their odds of meeting national MVPA guidelines were also 2.54 times worse than healthy participants.

Current practice: postoperative and return to play trends after ACL reconstruction by fellowship-trained sports surgeons

PURPOSE

Advances in anterior cruciate ligament (ACL) reconstruction have allowed for many progressions in postoperative management. However, there is no standardized protocol for immediate postoperative management or return to play. Our objective was to evaluate current trends in immediate postoperative and return to sport practices after ACL reconstruction.

LEVEL OF EVIDENCE

Cross sectional study, Level IV.

METHODS

Surveys were obtained from four large sports fellowship alumni networks. Demographics included years of practice and ACLs performed per year. Postoperative questions included weight bearing status, brace use and continuous passive motion (CPM) use. Return to play included time for return, brace use and metrics used for clearance to sport.

RESULTS

A total of 143 surveys were completed (32% response rate). Average years in practice were 15.1 years. Average ACL reconstructions performed per year was 20-50 in 44% and 50-100 in 29%. 26% used CPM in all patients, 8% if concomitant meniscal repair and 66% never. Bracing after surgery was used in 84% and 48% after return to play. Return to play was allowed at 6-9 months in 67% and overall 94% from 6 to 12 months. No consensus on return to play metrics was used, with the hop test being most important followed by specific time point after surgery.

CONCLUSION

Immediate weight bearing after surgery is commonplace with intermittent CPM use. Bracing is common postoperatively and half the time with return to play. Return to play is typically allowed after at least 6 months with no consensus on return to sport metrics. Years after fellowship and ACLs performed yearly had no correlation with postoperative practices.

Anatomic and Histological Study of the Anterolateral Aspect of the Knee: A SANTI Group Investigation

Background:

The structure and function of the anterolateral aspect of the knee have been significantly debated, with renewed interest in this topic since the description of the anterolateral ligament (ALL).

Purpose:

To define and describe the distinct structures of the lateral knee and to correlate the macroscopic and histologic anatomic features.

Study Design:

Descriptive laboratory study.

Methods:

Twelve fresh-frozen human cadavers were used for anatomic analysis. In the left knee, a layer-by-layer dissection and macroscopic analysis were performed. In the right knee, an en bloc specimen was obtained encompassing an area from the Gerdy tubercle to the posterior fibular head and extending proximally from the anterior aspect to the posterior aspect of the lateral femoral epicondyle. The en bloc resection was then frozen, sliced at the level of the joint line, and reviewed by a musculoskeletal pathologist.

Results:

Macroscopically, the lateral knee has 4 main layers overlying the capsule of the knee: the aponeurotic layer, the superficial layer including the iliotibial band (ITB), the deep fascial layer, and the ALL. Histologically, 8 of 12 specimens demonstrated 4 consistent, distinct structures: the ITB, the ALL, the lateral collateral ligament, and the meniscus.

Conclusion:

The lateral knee has a complex orientation of layers and fibers. The ALL is a distinct structure from the ITB and is synonymous to the previously described capsulo-osseous layer of the ITB.

Clinical Relevance:

Increasingly, lateral extra-articular procedures are performed at the time of anterior cruciate ligament reconstruction. Understanding the anatomic features of the anterolateral aspect of the knee is necessary to understand the biomechanics and function of the structures present and allows surgeons to attempt to replicate those anatomic characteristics when performing extra-articular reconstruction.

Sex Differences in Common Sports Injuries

Common sports injuries include bone stress injuries (BSIs), anterior cruciate ligament (ACL) injuries, and concussions. Less commonly recognized are the specific sex differences in epidemiology, risk factors, and outcomes of these conditions by sex. An understanding of these factors can improve their clinical management, from prescribing appropriate prehabilitation to guiding postinjury rehabilitation and return to play. This narrative review summarizes the sex differences in the diagnosis and management of BSIs, ACL injuries, and concussions. Although BSIs are more common in female athletes, risk factors for both sexes include prior injury and relative energy deficiency in sport (RED-S). Risk factors in female athletes include smaller calf girth, femoral adduction, and higher rates of loading. Female athletes are also at greater risk for developing ACL injuries in high school and college, but their injury rate is similar in professional sports. Increased lateral tibial slope, smaller ACL size, and suboptimal landing mechanics are additional risk factors more often present in female athletes. Male athletes are more likely to have ACL surgery and have a higher rate of return to sport. Concussions occur more commonly in female athletes; however, female athletes are also more likely to report concussions. Male athletes more commonly sustain concussion through contact with another player. Female athletes more commonly sustain injury from contact with playing equipment. Managing post-concussion symptoms is important, and female athletes may have prolonged symptoms. An understanding of the sex-specific differences in these common sports injuries can help optimize their prehabilitation and rehabilitation. LEVEL OF EVIDENCE: IV.

Countermovement Jump and Isokinetic Dynamometry as Measures of Rehabilitation Status After Anterior Cruciate Ligament Reconstruction

CONTEXT

  Despite an increase in the literature, few definitive guidelines are available to determine when an athlete has been fully rehabilitated after anterior cruciate ligament reconstruction (ACLR).

OBJECTIVE

  To examine countermovement jump and isokinetic dynamometry measures to (1) identify which measures can best distinguish between ACLR and control participants and (2) provide normative values for identified measures in young adult male multidirectional field-sport athletes.

DESIGN

  Cross-sectional study.

SETTING

  Orthopaedic hospital.

PATIENTS OR OTHER PARTICIPANTS

  Young adult male multidirectional field-sport athletes (n = 118) who had undergone unilateral patellar-tendon graft ACLR at least 6 months earlier and healthy male participants (n = 44) with no previous knee injury.

INTERVENTION(S)

  Single-legged countermovement jump (SL CMJ).

MAIN OUTCOME MEASURE(S)

  Three-dimensional biomechanical analysis of the SL CMJ and mean peak concentric knee-extension and -flexion torque using isokinetic dynamometry (ISO) were compared in the 2 groups. A stepwise logistic regression was carried out to identify the best predictors of ACLR- or control-group membership (SL CMJ height, limb symmetry index, peak power, joint power contribution, ISO peak torque, limb symmetry index variables).

RESULTS

  The control group differed strongly from the ACLR group in isokinetic knee-extension peak torque (d = -1.33), SL CMJ performance (d > 0.4), and limb symmetry measures in both ISO and jump outcomes (d > 1.1). The combination of measures from both ISO and SL CMJ identified group membership with an accuracy of 89%.

CONCLUSIONS

  Rehabilitation of ACLR patients may be complete when they achieve isokinetic knee-extension peak torque of 260% (±40%) body mass, SL CMJ performance of >17 cm (±4 cm), and reach-limb symmetry measures of >90% in both strength and jump outcomes. The outcomes in the control group can inform return-to-play criteria for young adult male multidirectional field-sport athletes after ACLR.

Factors associated with additional anterior cruciate ligament reconstruction and register comparison: a systematic review on the Scandinavian knee ligament registers

Objective

To present an overview of the Scandinavian knee ligament registers with regard to factors associated with additional ACL reconstruction, and studies comparing the Scandinavian registers with other knee ligament registers.

Design

Systematic review.

Data sources

Four electronic databases: PubMed, EMBASE, the Cochrane Library and AMED were searched, and 157 studies were identified. Two reviewers independently screened titles, abstracts and full-text studies for eligibility. A modified version of the Downs and Black checklist was applied for quality appraisal.

Eligibility criteria for selecting studies

Eligible studies were those published since the establishment of the Scandinavian registers in 2004, which reported factors associated with additional ACL reconstruction and compared data from other registers.

Results

Thirty-one studies met the inclusion criteria and generally displayed good reporting quality. Adolescent age (<20 years) was the most common factor associated with additional ACL reconstruction. The choice of hamstring tendon graft compared with patella tendon, transportal femoral tunnel drilling, smaller graft diameter and utilisation of suspensory fixation devices were associated with additional ACL reconstruction. Concomitant cartilage injury decreased the likelihood of additional ACL reconstruction. Patient sex alone did not influence the likelihood. The demographics of patients undergoing ACL reconstruction in the Scandinavian registers are comparable to registers in other geographical settings. However, there are differences in surgical factors including the presence of intra-articular pathology and graft choice.

Summary

The studies published from the Scandinavian registers in general have a high reporting quality when regarded as cohort studies. Several factors are associated with undergoing additional ACL reconstruction. The results from the registers may help facilitate treatment decisions.

Sex-based Differences in Common Sports Injuries

The patient's sex plays an important role in mediating the risk for, and experience of, disease. Injuries of the musculoskeletal system are no exception to this phenomenon. Increasing evidence shows that the incidence, clinical presentation, and treatment outcomes for male and female patients with common sports injuries may vary widely. Stress fracture, which is associated with the female athlete triad, is a sports injury with known sex-based differences. Other common sports-related injuries may also have distinct sex-based differences. Understanding these differences is important to optimize each patient's musculoskeletal care.

Multivariate genome-wide association analysis identifies novel and relevant variants associated with anterior cruciate ligament rupture risk in the dog model

Background

Anterior cruciate ligament rupture (ACLR) is a debilitating and potentially life-changing condition in humans, as there is a high prevalence of early-onset osteoarthritis after injury. Identification of high-risk individuals before they become patients is important, as post-treatment lifetime burden of ACLR in the USA ranges from $7.6 to $17.7 billion annually. ACLR is a complex disease with multiple risk factors including genetic predisposition. Naturally occurring ACLR in the dog is an excellent model for human ACLR, as risk factors and disease characteristics in humans and dogs are similar. In a univariate genome-wide association study (GWAS) of 237 Labrador Retrievers, we identified 99 ACLR candidate loci. It is likely that additional variants remain to be identified. Joint analysis of multiple correlated phenotypes is an underutilized technique that increases statistical power, even when only one phenotype is associated with the trait. Proximal tibial morphology has been shown to affect ACLR risk in both humans and dogs. In the present study, tibial plateau angle (TPA) and relative tibial tuberosity width (rTTW) were measured on bilateral radiographs from purebred Labrador Retrievers that were recruited to our initial GWAS. We performed a multivariate genome wide association analysis of ACLR status, TPA, and rTTW.

Results

Our analysis identified 3 loci with moderate evidence of association that were not previously associated with ACLR. A locus on Chr1 associated with both ACLR and rTTW is located within ROR2, a gene important for cartilage and bone development. A locus on Chr4 associated with both ACLR and TPA resides within DOCK2, a gene that has been shown to promote immune cell migration and invasion in synovitis, an important predictor of ACLR. A third locus on Chr23 associated with only ACLR is located near a long non-coding RNA (lncRNA). LncRNA’s are important for regulation of gene transcription and translation.

Conclusions

These results did not overlap with our previous GWAS, which is reflective of the different methods used, and supports the need for further work. The results of the present study are highly relevant to ACLR pathogenesis, and identify potential drug targets for medical treatment.

Electronic supplementary material

The online version of this article (10.1186/s12863-018-0626-7) contains supplementary material, which is available to authorized users.