Return to play after anterior cruciate ligament reconstruction in National Football League athletes

Risk of Anterior Cruciate Ligament Tears in National Football League Players by Short, Normal, or Long Rest Weeks

Anterior cruciate ligament (ACL) tears in National Football League (NFL) players are devastating injuries that take nearly a year to recover. Players that do return to sport have worse overall performance compared to pre-ACL tear. NFL players typically play regular season games on Sunday with the next game played on the following Sunday, allowing for 6 days between games. Deviation from the usual 6-day rest week has been proposed as a potential risk for ACL tear. The main objective of this study was to evaluate the risk of decreased rest or increased rest on ACL tear rates in NFL players. ACL injury data of NFL players from the 2012 to 2013 season and 2022 to 2023 season were gathered from publicly available sources. Player demographic data, position, age at time of injury, seasons played, injury mechanism, and playing surface type were recorded. Injuries were characterized as short, normal, or long week injuries. ACL tears that occurred during the preseason, postseason, or during week 1 were excluded. Descriptive statistics were calculated to report means, ranges, and percentages. Data were analyzed to determine statistically significant differences using Fisher's exact, chi-square, or one-way analysis of variance tests. A total of 524 ACL tears were recorded in NFL players during the study window. Note that 304 ACL tears were excluded and 220 fit inclusion criteria. Twenty-four ACL tears occurred during short weeks, 68 during long weeks, and 128 during normal weeks. Players were 1.8 times more likely to tear their ACL during a long week compared to a normal week (p < 0.001), and 1.5 times more likely to tear their ACL during a short week compared to a normal week (p = 0.02). The findings from this study suggest that deviation from the normal 7-day NFL week increases the risk of an ACL tear in NFL players when increasing or decreasing rest time. Further research exploring the impact of short and long rest times on player injury risk should be conducted to prevent season-ending injuries.

Practice Patterns and Return-to-Sports Timing of National Football League Head Team Physicians for ACL Reconstruction

Background

Previous surveys of the practice patterns for anterior cruciate ligament (ACL) reconstruction in collegiate and professional team physicians have shown bone-patellar tendon-bone (BPTB) autograft being the most common graft, with variable return-to-sports timing.

Purpose

To evaluate the current practice patterns and return-to-sports timing of National Football League (NFL) head team physicians for ACL reconstruction.

Study Design

Cross-sectional study.

Method

All 32 NFL head team orthopaedic surgeons were surveyed and asked their primary ACL graft preference, revision ACL graft preference, use of lateral extra-articular tenodesis (LET) or anterolateral ligament reconstruction (ALL), use of suture brace augmentation, return-to-sport timing, and whether functional testing was utilized in determining readiness of return to play. The years of experience of the physician were also evaluated.

Results

All 32 head team physicians responded, with 31 (97%) using ipsilateral BPTB autograft in the primary setting and 1 using ipsilateral quadriceps autograft. In the revision setting, 24 (75%) physicians preferred a contralateral BPTB autograft, while 5 (16%) used an ipsilateral quadriceps autograft, 1 (3%) used a contralateral quadriceps autograft, and 2 (6%) used a BPTB allograft. One respondent (3%) used suture brace augmentation "most of the time" in the primary setting and always in the revision setting. No respondents utilized an ALL or LET in the primary setting and 2 (6%) respondents always performed an LET in revisions. Five others (16%) have performed at least 1 ALL or LET in an NFL athlete. Mean return to sports was at 9 months postoperatively, with no physicians allowing players to return before 7 months. All but 1 respondent used functional testing in return-to-sports decision-making.

Conclusion

All but 1 of the 32 NFL head team physicians used BPTB autograft in primary ACL reconstruction. The majority preferred contralateral BPTB autograft in revisions, with a few considering extra-articular procedures or suture bracing in addition. On average, head team physicians allowed players to return at 9 months postoperatively, with none allowing return before 7 months. Nearly all utilized functional testing to aid in return-to-play decision-making. These homogenous findings in this high-risk and public athletic cohort aid in patient education and clinical decision-making for best treatment of ACL injuries, particularly in contact athletes.

Anterior Cruciate Ligament Ruptures in Russian Premier League Soccer Players During the 2010 to 2021/2022 Competitive Seasons: The Epidemiology and Details of Return to Sports

Background

There are limited data on the epidemiology of anterior cruciate ligament (ACL) ruptures in elite adult soccer players, especially in the Russian Premier League (RPL). There is an increased risk of injury due to a combination of additional risk factors such as playing in extremely high and low temperatures, frequent long flights, and regular play on natural and artificial surfaces.

Purpose

To study the epidemiology of ACL ruptures and determine the patterns associated with their occurrence in RPL soccer players.

Study Design

Descriptive epidemiology study.

Methods

All ACL ruptures requiring surgery sustained by players competing in the RPL across 12 competitive seasons between 2010 and 2022 were analyzed. All required data were collected from media analysis and confirmed by club doctors.

Results

A total of 85 players sustained 100 injuries during 12 competitive seasons. A total of 96.5% of players returned to competitive play. The injury incidence in RPL and during participation of RPL teams in European Cups were 0.4760 and 0.5622 per 1000 playing hours, respectively. When analyzing the outcomes of the primary ACL surgery (a total of 76 operations), the following data were obtained: in 11 cases (14.5%), there was a reinjury on the ipsilateral knee joint and in 4 cases (5.3%) on the contralateral knee joint. The mean return-to-play time after all operations was 284 ± 116 days. The time of return to play after primary reconstruction was 289 ± 136 days, 278 ± 91 days after reconstruction on the contralateral knee and 271 ± 51.5 days after the first ACL revision reconstruction on the ipsilateral knee joints.

Conclusion

RPL ACL injury epidemiology is similar to that in the other leagues from around the world, although there are factors that can potentially influence the number of these injuries.

Long-term Outcomes of Multiligament Knee Injuries in American Football Players

BACKGROUND

Long-term outcomes for isolated anterior cruciate ligament (ACL) reconstructions in competitive American football athletes are well reported in the literature, but little data currently exist regarding multiligament knee injury (MLKI) reconstruction outcomes.

PURPOSE

To examine patient-reported and return-to-sport outcomes of competitive American football athletes who underwent primary, single-staged, multiligament knee reconstruction.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

We identified patients from our institution's prospectively collected data repository between 2001 and 2020 who underwent single-staged surgical reconstruction of an MLKI sustained during competitive participation in American football. We assessed patient-reported outcomes at a minimum of 2 years after surgery using the International Knee Documentation Committee (IKDC) Subjective Knee Form and questions regarding surgical satisfaction and return to sport. Successful return to sport was defined as a return to preinjury level of competition. We summarized all outcome data and compared outcomes between 2-ligament and >2-ligament groups and between ACL-only MLKI injury and bicruciate MLKI injury groups using independent t test for IKDC scores and chi-square test for return to sport. Additionally, we evaluated predictors of postoperative IKDC scores using linear regression and predictors of return to sport using logistic regression.

RESULTS

Outcome data were successfully collected for 53 of 73 total eligible patients (73%; mean follow-up time, 7.7 ± 4.0 years; all male; mean age at surgery, 18.1 ± 2.7 years). The mean postoperative IKDC score was 84 ± 16. The most common level of preinjury competition was high school (n = 36; 68%), followed by college (n = 10; 19%). Seven patients did not return to sport competition at any level due to limitations from their knee surgery, and 82% of patients that attempted to return to preinjury level of sport were able to do so. A total of 50 patients (94%) were satisfied or very satisfied with their surgical outcome. The 2-ligament (n = 39) and >2-ligament (n = 14) groups did not significantly differ in IKDC scores (P = .96) or proportions with successful return to sport (P = .77). Similarly, the ACL-MLKI injury (n = 39) and bicruciate MLKI injury (n = 14) groups did not significantly differ in IKDC scores (P = .89) or proportions with successful return to sport (P = .77). Age and body mass index were not significantly associated with IKDC scores or successful return to sport at follow-up (all P > .05).

CONCLUSION

This study may represent the largest cohort of competitive American football athletes evaluated for longitudinal outcomes after multiligament knee reconstruction. Despite the severity of these injuries, we found good knee-related function and that the large majority of athletes who attempted to return to sport were successful. The majority of athletes (94%) were satisfied with their operative treatment.

Psychological Impact and Posttraumatic Stress Disorder Symptomatology After Ulnar Collateral Ligament Injuries in Baseball Players

Background

Significant psychological impact and prevalence of posttraumatic stress disorder (PTSD) have been well documented in patients sustaining anterior cruciate ligament injury.

Purpose

To examine PTSD symptomatology in baseball players after sustaining elbow ulnar collateral ligament (UCL) injury.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

Male baseball players of various competition levels (high school through Minor League Baseball [MiLB]) who underwent surgery for a UCL injury between April 2019 and June 2022 participated in the study. Before surgery, patients completed the Impact of Event Scale-Revised (IES-R) to assess PTSD symptomatology. Subgroup analysis was conducted according to level of play and player position.

Results

A total of 104 male baseball players with a mean age of 19.4 years (range, 15-29 years) were included in the study; 32 players (30.8%) were in high school, 65 (62.5%) were in college, and 7 (6.7%) were in MiLB. There were 64 (61.5%) pitchers, 18 (17.3%) position players, and 22 (21.2%) 2-way players (both pitching and playing on the field). A total of 30 (28.8%) patients scored high enough on the IES-R to support PTSD as a probable diagnosis, and another 22 patients (21.2%) scored high enough to support PTSD as a clinical concern. Nineteen patients (18.3%) had potentially severe PTSD. Only 4 players (3.8%) were completely asymptomatic. Subgroup analysis revealed college players as significantly more symptomatic than high school players (P = .02), and 2-way players were found to be significantly less susceptible to developing symptoms of PTSD compared with pitchers (P = .04).

Conclusion

Nearly 30% of baseball players who sustained a UCL injury qualified for a probable diagnosis of PTSD based on the IES-R. Pitchers and college athletes were at increased risk for PTSD after UCL injury compared with 2-way players and high school athletes, respectively.

Differences in Biomechanical Determinants of ACL Injury Risk in Change of Direction Tasks Between Males and Females: A Systematic Review and Meta-Analysis

BACKGROUND

Change of direction (COD) movements are associated with non-contact anterior cruciate ligament (ACL) injuries in multidirectional sports. Females appear at increased risk compared to males, which could be attributable to whole body kinematic strategies and greater multiplanar knee joint loads (KJLs) during COD which can increase ACL loading.

OBJECTIVE

The aim of this systematic review and meta-analysis was to examine and quantitatively synthesise the evidence for differences between males and females regarding KJLs and their biomechanical determinants (whole body kinematic strategies determining KJLs) during COD tasks.

METHODS

Databases including SPORTDiscus, Web of Science, and PubMed were systematically searched (July 2021-June 2023) for studies that compared differences in knee joint loads and biomechanical determinants of KJLs during COD between males and females. Inclusion criteria were: (1) females and males with no prior history of ACL injury (18-40 years); (2) examined biomechanical determinants of KJLs and/ or KJLs during COD tasks > 20°; (3) compared ≥ 1 outcome measure between males and females. Studies published between 2000 and 2023 examining a cutting task > 20° with a preceding approach run that compared KJLs or the whole body multiplanar kinematics associated with them, between sexes, using three-dimensional motion analysis.

RESULTS

This meta-analysis included 17 studies with a pooled sample size of 451 participants (227 males, 224 females). Meta-analysis revealed females displayed significantly less peak knee flexion during stance (SMD: 0.374, 95% CI 0.098-0.649, p = 0.008, I2: 0%); greater knee abduction at initial contact (IC) (SMD: 0.687, 95% CI 0.299-1.076, p = 0.001, I2: 55%); less hip internal rotation (SMD: 0.437, 95% CI 0.134-0.741, p = 0.005, I2: 34%) and hip abduction at IC (SMD: -0.454, 95% CI 0.151-0.758, p = 0.003, I2: 33%). No significant differences were observed between males and females for any internal or externally applied KJLs. All retrieved studies failed to control for strength, resistance training or skill history status.

CONCLUSION

No differences were observed in KJLs between males and females despite females displaying greater knee abduction at IC and less peak knee flexion during the stance phase of CODs, which are visual characteristics of non-contact ACL injury. Further research is required to examine if this translates to a similar injury risk, considering morphological differences in strain characteristics of the ACL between males and females. This observation may in part explain the disproportionate ACL injury incidence in female multidirectional athletes. Further higher quality controlled research is required whereby participants are matched by skill training history, resistance training history and strength status to ensure an appropriate comparison between males and females.

Suture-Augmented Anterior Cruciate Ligament Repair for Proximal Avulsion or High-Grade Partial Tears Shows Similar Side-to-Side Difference and No Clinical Differences at Two Years Versus Conventional Anterior Cruciate Ligament Reconstruction for Mid-Substance Tears or Poor Anterior Cruciate Ligament Tissue Quality

PURPOSE

To compare objective and subjective clinical outcomes between suture-augmented anterior cruciate ligament (ACL) repair (SAACLR) and conventional ACL reconstruction (CACLR) with minimum 2-year follow-up.

METHODS

In this nonrandomized, prospective study, 30 patients underwent SAACLR for proximal ACL avulsion or high-grade partial ACL tear (Sherman grade 1 or 2) and 30 patients underwent CACLR for proximal one-third/distal two-thirds junction tears and mid-substance tears (Sherman grade 3 or 4) tear types by 1 surgeon between 2018 and 2020. Failure was defined as ACL reinjury. Outcome measures were KT-1000 for side-to-side knee laxity evaluation, Visual Analog Scale for pain, International Knee Documentation Committee (IKDC) Subjective Knee Evaluation Form, Knee Injury and Osteoarthritis Severity Score (KOOS), Tegner Activity Scale, Western Ontario and McMaster Universities Osteoarthritis Index, Lysholm Knee Scoring Scale, and Single Assessment Numeric Evaluation. Minimal clinically important difference (MCID) was calculated for IKDC and KOOS subscores.

RESULTS

Three failures (10%) occurred in the SAACLR group, with no failures in the CACLR group (P = .24). A total of 23 (85%) SAACLR patients and 27 (90%) CACLR patients had patient-reported outcomes and physical examination at minimum 2 years. Two-year KT-1000 testing with 20 lbs showed less than 1 mm side-to-side difference between the groups. No significant differences in the percentage of patients meeting the MCID were found between the SAACLR and CACLR groups at 2 years: IKDC, 10.81 (82%) versus 10.54 (93%) (P = .48); KOOS Pain, 11.55 (73%) versus 10.58 (78%) (P = .94); KOOS Symptoms, 8.15 (77%) versus 10.32 (74%) (P = 1.0); KOOS Activities of Daily Living, 12.19 (59%) versus 12.28 (70%) (P = .60); 18.99 (71%) versus 16.77 (86%) (P = .42). Significantly higher IKDC scores were observed with SAACLR versus CACLR at 3 months (P = .01) and 6 months (P = .02), and significantly higher Lysholm scale, Tegner Activity Scale, and all KOOS subscale scores were observed at 6 months.

CONCLUSIONS

At 2 years after surgery, KT-1000 testing showed less than 1 mm side-to-side difference and no differences were observed between the groups in the percentage of patients who met or exceeded the MCID. Significantly higher early patient-reported outcome scores were found with SAACLR versus CACLR. The rerupture rate between the groups was not significantly different.

LEVEL OF EVIDENCE

Level II, Prospective cohort study.

Does playing surface affect the risk of anterior cruciate ligament injuries in the National Football League? A look at the 2017 - 2021 NFL seasons

BACKGROUND

Anterior cruciate ligament (ACL) injuries are devastating injuries for athletes. Prior studies have shown increased ACL injury rates on non-natural surfaces versus natural grass in several sports. The purpose of this study is to calculate the prevalence of ACL injuries in the NFL on natural versus non-natural surfaces to determine if there is a significant increase on non-natural surfaces.

METHODS

Accessing publicly available data for NFL seasons beginning with the 2017-2018 season through 2021-2022 seasons, all ACL injuries with publicly available data concerning timing and playing surface were recorded and categorized according to playing surface. Practice injuries or those without an identifiable playing surface were excluded. Incidence rates, defined as ACL ruptures per game, were calculated. ACL injuries were recorded for each playing surface, as well as the combined category of non-natural grass surface. Odds ratio was calculated to compare the risk of ACL rupture on non-natural surfaces vs natural grass.

RESULTS

During the 2017-2021 NFL seasons, 173 ACL ruptures were identified with known surfaces. Injury rate for non-natural surfaces was 0.134 compared to 0.097 for grass. Injury rate ratio for non-natural vs natural grass surfaces was 1.211, a 21.1% increased risk of ACL injury in the NFL on non-natural surfaces vs natural grass. OR for non-natural surfaces 1.239 (95% CI 0.900-1.704). Based on these findings there is a trend toward increased risk of ACL injury on non natural grass surfaces, however this did not reach statistical significance.

CONCLUSION

Numerous published studies show trends toward increasing rates of ACL injuries on non-natural playing surfaces vs natural grass. Based on our findings the difference is not statistically significant, however it does trend toward increased risk of ACL injury with non-natural surfaces. Further studies should be performed with larger sample sizes in order to further determine the risk of non-natural surfaces.

Lower hamstring to quadriceps muscle strength ratio and lower body weight as factors associated with noncontact anterior cruciate ligament injury in male American football players: A prospective cohort study

Background

Previous studies have aimed to determine the use of certain risk factors in predicting the occurrence of noncontact anterior cruciate ligament (ACL) injuries. Unfortunately, evidence regarding noncontact ACL injuries in male American football players is limited. This prospective cohort study aimed to identify intrinsic risk factors for noncontact ACL injury among male American football players.

Methods

This study evaluated 152 male American football players in Japan for potential noncontact ACL injury risk factors during a preseason medical assessment, including anthropometric, joint laxity, and flexibility, muscle flexibility, muscle strength, and balance measurements. A total of 25 variables were examined. Participants were monitored during each season for noncontact ACL injury, as diagnosed by physicians.

Results

Noncontact ACL injuries occurred in 11 knees of 11 players (prevalence; 7.1 %). Injured players were significantly more likely to have lightweight (P = 0.049). No statistically significant between-group differences were found for any other variables. Participants with a lower hamstring to quadriceps (H/Q) ratio (P = 0.04) were more likely to sustain noncontact ACL injuries.

Conclusion

Lower H/Q ratio and lower body weight were significantly associated with new-onset noncontact ACL injury in male American football players. These findings will help develop strategies to prevent noncontact ACL injuries in male American football players.

Predictors of Return to Activity at 2 Years After Anterior Cruciate Ligament Reconstruction Among Patients With High Preinjury Marx Activity Scores: A MOON Prospective Cohort Study

BACKGROUND

Predictors of return to activity after anterior cruciate ligament reconstruction (ACLR) among patients with relatively high preinjury activity levels remain poorly understood.

PURPOSE/HYPOTHESIS

The purpose of this study was to identify predictors of return to preinjury levels of activity after ACLR, defined as achieving a Marx activity score within 2 points of the preinjury value, among patients with Marx activity scores of 12 to 16 who had been prospectively enrolled in the Multicenter Orthopaedic Outcomes Network (MOON) cohort. We hypothesized that age, sex, preinjury activity level, meniscal injuries and/or procedures, and concurrent articular cartilage injuries would predict return to preinjury activity levels at 2 years after ACLR.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

All unilateral ACLR procedures from 2002 to 2008 performed in patients enrolled in the MOON, with preinjury Marx activity scores ranging from 12 to 16, were evaluated with a specific focus on return to preinjury activity levels at 2 years postoperatively. Return to activity was defined as a Marx activity score within 2 points of the preinjury value. The proportion of patients able to return to preinjury activity levels was calculated, and multivariable modeling was performed to identify risk factors for patients' inability to return to preinjury activity levels.

RESULTS

A total of 1188 patients were included in the final analysis. The median preinjury Marx activity score was 16 (interquartile range, 12-16). Overall, 466 patients (39.2%) were able to return to preinjury levels of activity, and 722 patients (60.8%) were not able to return to preinjury levels of activity. Female sex, smoking at the time of ACLR, fewer years of education, lower 36-Item Short Form Health Survey Mental Component Summary scores, and higher preinjury Marx activity scores were predictive of patients' inability to return to preinjury activity levels. Graft type, revision ACLR, the presence of medial and/or lateral meniscal injuries, a history of meniscal surgery, the presence of articular cartilage injuries, a history of articular cartilage treatment, and the presence of high-grade knee laxity were not predictive of a patient's ability to return to preinjury activity level.

CONCLUSION

At 2 years after ACLR, most patients with high preinjury Marx activity scores did not return to their preinjury level of activity. The higher the preinjury Marx activity score that a patient reported at the time of enrollment, the less likely he/she was able to return to preinjury activity level. Smoking and lower mental health at the time of ACLR were the only modifiable risk factors in this cohort that predicted an inability to return to preinjury activity levels. Continued effort and investigation are required to maximize functional recovery after ACLR in patients with high preinjury levels of activity.

MRI Findings Associated With Anterior Cruciate Ligament Tears in National Football League Athletes

Background

Anterior cruciate ligament (ACL) tears are a high-frequency injury requiring a lengthy recovery in professional American football players. Concomitant pathology associated with ACL tears as identified on magnetic resonance imaging (MRI) is not well understood in these athletes.

Purpose

To describe the MRI findings of concomitant injuries associated with ACL tears among athletes in the National Football League (NFL).

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

Of 314 ACL injuries in NFL athletes from 2015 through 2019, 191 complete MRI scans from the time of primary ACL injury were identified and reviewed by 2 fellowship-trained musculoskeletal radiologists. Data were collected on ACL tear type and location, as well as presence and location of bone bruises, meniscal tears, articular cartilage pathology, and concomitant ligament pathology. Mechanism data from video review were linked with imaging data to assess association between injury mechanism (contact vs noncontact) and presence of concomitant pathology.

Results

Bone bruises were evident in 94.8% of ACL tears in this cohort, most often in the lateral tibial plateau (81%). Meniscal, additional ligamentous, and/or cartilage injury was present in 89% of these knees. Meniscal tears were present in 70% of knees, lateral (59%) more than medial (41%). Additional ligamentous injury was present in 71% of all MRI scans, more often a grade 1/2 sprain (67%) rather than a grade 3 tear (33%), and most often involving the medial collateral ligament (MCL) (57%) and least often the posterior cruciate ligament (10%). Chondral damage was evident in 49% of all MRI scans, with ≥1 full-thickness defect in 25% of all MRI scans, most often lateral. Most (79%) ACL tears did not involve direct contact to the injured lower extremity. Direct contact injuries (21%) were more likely to have a concomitant MCL tear and/or medial patellofemoral ligament injury and less likely to have a medial meniscal tear.

Conclusion

ACL tears were rarely isolated injuries in this cohort of professional American football athletes. Bone bruises were almost always present, and additional meniscal, ligamentous, and chondral injuries were also common. MRI findings varied by injury mechanism.

Return to Sport After Multiligament Knee Injury in Young Athletes

Background

While return to sport (RTS) in young athletes after anterior cruciate ligament (ACL) reconstruction has been well studied, little is known regarding their rate of RTS after multiligament knee injury (MLKI).

Purpose

To assess the level of and factors associated with RTS after MLKI in young athletes.

Study Design

Case series; Level of evidence, 4.

Methods

We retrospectively identified 116 patients aged ≤23 years who had sustained an injury to ≥2 knee ligaments and undergone operative reconstruction or repair of ≥1 ligament. Our primary outcome was self-reported RTS at the preinjury level or higher. We estimated the likelihood of RTS using binomial logistic regression. Secondary variables included the 2000 International Knee Documentation Committee Subjective Knee Form (IKDC-SF), ACL-Return to Sport after Injury (ACL-RSI), and 12-Item Short Form Health Survey (SF-12) physical and mental health summaries.

Results

A total of 30 (25.9%) patients (24 men, 6 women; mean age, 18.1 ± 2.5 years) completed patient-reported outcome surveys at a mean follow-up of 7.8 years (median, 6.6 years [range, 1.1-19.5 years]). A total of 28 patients underwent surgical treatment of ≥2 ligaments. RTS was achieved by 90% of patients, and 43.3% returned to their preinjury level or higher. Patients who had played sports at a higher level before injury were more likely to RTS at their preinjury level or higher (odds ratio [OR], 3.516 [95% CI, 1.034-11.955]; P = .044), while those who played cutting sports were less likely to do so (OR, 0.013 [95% CI, 0.000-0.461; P = .017). Patients who achieved RTS at their preinjury level or higher had significantly higher IKDC-SF and ACL-RSI scores versus patients who did not (P = .001 and P = .002, respectively). The number of ligaments injured, age, mental health diagnosis, and SF-12 scores were not associated with the ability to RTS at the preinjury or higher levels.

Conclusion

Most young athletes who sustained MLKI were able to return to play at some level, but a minority returned to their preinjury level. Patients who did return at preinjury or higher levels had higher IKDC-SF and ACL-RSI scores than those who did not. Performance in cutting and/or pivoting sports was negatively associated with RTS.

Musculoskeletal Injury in American Football: A Bibliometric Analysis of the Most Cited Articles

Background

Textbook knowledge and clinical dogma are often insufficient for effective evidence-based decision making when treating musculoskeletal injuries in American football players, given the variability in presentation and outcomes across different sports and different levels of competition. Key evidence can be drawn directly from high-quality published articles to make the appropriate decisions and recommendations for each athlete's unique situation.

Purpose

To identify and analyze the 50 most cited articles related to football-related musculoskeletal injury to provide an efficient tool in the arsenal of trainees, researchers, and evidence-based practitioners alike.

Study Design

Cross-sectional study.

Methods

The ISI Web of Science and SCOPUS databases were queried for articles pertaining to musculoskeletal injury in American football. For each of the top 50 most cited articles, bibliometric elements were evaluated: citation count and density, decade of publication, journal, country, multiple publications by the same first author or senior author, article content (topic, injury area), and level of evidence (LOE).

Results

The mean ± SD number of citations was 102.76 ± 37.11; the most cited article, with 227 citations, was "Syndesmotic Ankle Sprains" published in 1991 by Boytim et al. Several authors served as a first or senior author on >1 publication, including J.S. Torg (n = 6), J.P. Bradley (n = 4), and J.W. Powell (n = 4). The American Journal of Sports Medicine published the majority of the 50 most cited articles (n = 31). A total of 29 articles discussed lower extremity injuries, while only 4 discussed upper extremity injuries. The majority of the articles (n = 28) had an LOE of 4, with only 1 article having an LOE of 1. The articles with an LOE of 3 had the highest mean citation number (133.67 ± 55.23; F = 4.02; P = .05).

Conclusion

The results of this study highlight the need for more prospective research surrounding the management of football-related injury. The low overall number of articles on upper extremity injury (n = 4) also highlights an area for further research.

Use of Fantasy Points in Evaluating Professional Athlete Performance After Anterior Cruciate Ligament (ACL) Reconstruction

Our aim in performing this study was to evaluate whether fantasy and wins above replacement (WAR) scores of athletes undergoing anterior cruciate ligament (ACL) reconstructive surgery in the National Football League (NFL), National Basketball Association (NBA), National Hockey League (NHL), and Major League Baseball (MLB) could be utilized in evaluating their performance post-surgery. We identified publicly accessible data on professional athletes from 1992 to 2015. Fantasy and WAR scores were calculated for each player. A total of 83 professional players met the inclusion criteria for this cross-sectional study. Decreased fantasy scores ranged from 33% to 42% across the four leagues after the index operation. NHL players had the lowest return-to-play (RTP) rate at 11/17 (82%), and MLB players had the highest RTP rate at 14/15 (93%). RTP rates of NBA and NFL players were comparable at 22/26 (85%) and 22/25 (88%), respectively. NFL players had the lowest average career length after surgery at 26 months, while NBA players had the longest average career length at 64 months. MLB players on average required the longest time to return to the pre-surgical level of performance (21 months). NHL players had the shortest average recovery time (eight months), and NBA players had the longest average recovery time (13 months). Approximately, more than half of all the studied players exhibited a decline in fantasy or WAR scores. In addition, NFL players had the lowest average career length, and NBA players enjoyed the longest average career length after surgery. NHL players had the lowest recovery time, while NBA players had the longest recovery time. The strength of this study is the utilization of fantasy points and WAR scores as a single unifying measure of a player's performance, which acts as an objective measure after ACL reconstruction. The average performance of a professional athlete, as evaluated through their fantasy score output, tends to decrease after undergoing ACL reconstruction. There is an overall long-term performance decline after initial spikes in their performance after surgery. Additional larger studies are needed to fully understand the effects of ACL reconstruction in professional athletes; however, the use of fantasy scores may be an objective tool in measuring the success rate of ACL reconstruction.

The incidence of anterior cruciate ligament injury in youth and male soccer athletes: an evaluation of 17,108 players over two consecutive seasons with an age-based sub-analysis

PURPOSE

To evaluate the incidence of anterior cruciate ligament (ACL) injuries in male athletes from professional soccer clubs over two consecutive seasons (2018-2019) with a sub-analysis based on age category: under-13 (U-13), under-15 (U-15), under-17 (U-17), and under-20 (U-20) years.

METHODS

A total of 17,108 young male soccer players were retrospectively reviewed from sixty-three professional clubs in the four highest Brazilian soccer divisions. Data regarding the number of athletes and the number of ACL injuries confirmed by magnetic resonance imaging (MRI) exams in the 2018 and 2019 seasons were collected. Incidence of ACL injury were compared by season, age category (under-13; under-15; under 17; and under-20), demographic region, and club division.

RESULTS

Clubs from all regions of Brazil participated in the study. A total of 336 primary ACL injuries were diagnosed over the two seasons (8,167 athletes during the 2018 season and 8,941 athletes during the 2019 season) among all athletes, which corresponds to 2% of the included athletes. There were 11 cases (0.3%) in the under-13, 53 cases (1.3%) in the under-15, 107 cases (2.5%) in the under-17, and 165 cases (3.8%) in the under-20 age category. There was a higher incidence of ACL injury in the older age groups (p < 0.001).

CONCLUSION

A total of 336 ACL injuries were identified in 17,108 youth soccer players from 63 professional clubs with an overall incidence of 2% over 2 seasons of competition. ACL injury rate ranged from 0.3% to 3.8% and was higher in the older and more competitive club divisions.

LEVEL OF EVIDENCE

IV.

Physiotherapeutic approach to the preoperative period for the anterior cruciate ligament reconstruction: A systematic review

INTRODUCTION

The tearing of the anterior cruciate ligament (ACL) is one of the most common type of knee injury. Current evidence show that there are specific predictors for postoperative success in ACL injuries, but there is a limited number of studies on preoperative rehabilitation. Therefore, the goals of this review were to emphasize physiotherapy approaches to the preoperative period and to verify its effectiveness at the time the athlete returns to sport.

METHOD

We conducted a systematic search in these databases: Medline, Scielo, Lilacs, CINAHL, Web of Science, PeDro and Cochrane Library.

RESULTS

Our searches identified 553 occurences; of these, 511 titles and abstracts underwent triage after removal of duplicates. We identified 120 full texts for a stricter screening, amongst them, three studies included in the review for complying with the elegibility criteria.

CONCLUSION

Physiotherapic preoperative treatment exhibits weak evidence for strength gains and pain relief, as well as strong evidence of functional improvement compared to the control group. These results were reported 4 months after the ACLR, in average.

The Mechanism of Anterior Cruciate Ligament Injuries in the National Football League: A Systematic Video Review

Introduction Anterior cruciate ligament (ACL) injuries are common among American football athletes, although few studies have performed video analyses of ACL injuries to better understand the injury mechanism. This work aims to characterize the mechanism of ACL injury during professional football competitions using video analysis. We hypothesize that football-specific injury trends will emerge, including high rates of contact injuries and associations with shallow knee and hip flexion angles (0°-30°). Methods Videos of professional football players suffering ACL injuries from 2007 to 2016 were analyzed. Injured players were identified using the injured reserve (IR) lists of the National Football League (NFL), and videos were discovered via a systematic Google search. Descriptive statistics and frequency analyses were performed on all variables using the Statistical Package for the Social Sciences (SPSS) version 23.0 (IBM SPSS Statistics, Armonk, NY, USA). Results Of the 429 ACL injuries identified, 53 (12%) videos were available. Deceleration was the most common injury maneuver, present in 32 (60%) athletes. Thirty-one (58%) players suffered contact injuries. Twenty-eight (53%) injuries demonstrated valgus collapse of the knee, and 26 (49%) had neutral knee rotation. Defensive backs (26%) and wide receivers (23%) were the most frequently injured positions. Conclusion Overall, we found that most ACL injuries had preceding contact, deceleration, shallow hip and knee flexion, and heel strike, and subsequent valgus collapse and neutral knee rotation. This understanding of American football-specific ACL tear mechanisms could help direct the focus of future injury prevention training modalities.

Performance and return to sport after injury in professional mixed martial arts

BACKGROUND

Mixed Martial Arts (MMA) is an increasingly popular combat sport incorporating striking and grappling that results in a high incidence of injuries.

OBJECTIVES

The purpose of this study was to analyze the impact of injuries on the return to sport and post-injury performance of professional MMA athletes. We hypothesize that increased age is associated with lower probability of return to sport and diminished post-injury performance.

METHODS

Publicly available data (obtained from ESPN.com/MMA, UFC.com, Rotowire.com/MMA) from professional MMA fighters who resigned from fight cards due to injury from 2012 to 2014 were analyzed. Injury history, match history and outcomes, and duration of time to return to professional fighting were recorded and compared to a cohort consisting of uninjured opponents.

RESULTS

454 fighters were included in the analysis. The mean age at the time of injury was 30.0±3.9 years. 94.4% of injured athletes were able to return to professional MMA, and athletes required a mean duration of 6.8±6.7 months between injury and their next professional fight (range 0.3-58 months). There was no significant difference in winning percentage in the post-injury period between the injured group and the uninjured group (p = 0.691). Increased age at the time of injury was associated with the odds of being able to return to professional fighting after injury (OR = 0.822, p = 0.001).

CONCLUSION

In this analysis of publicly available injury data on MMA fighters, there was a high rate of return to professional sport and no evidence of an associated decline in performance following major injury requiring withdrawal from a fight card. Older age at the time of injury was associated with decreased odds of being able to return to professional fighting. With increasing popularity of combat sports, sport-specific prognostic information will help guide and treat specific injuries associated with MMA participation.

Factors affecting return to play and graft re-rupture after primary ACL reconstruction in professional footballers

PURPOSE

Modern ACL reconstruction (ACL-R) techniques have led to improved outcomes in professional footballers. The aim of this study was to identify and assess patient, surgical and post-operative factors that affected rates and time to return to play (RTP) as well as ACL re-rupture rates.

METHODS

A retrospective review of consecutive ACL-R undertaken in professional footballers between 2005 and 2018.

RESULTS

Two-hundred and thirty-two knees in 215 professional footballers (17 bilateral) were included. 205 (88.9%) were male and average age at surgery was 23.3 ± 4.4 years. Two-hundred and twenty-two (96.1%) returned to professional football, with 209 (90.1%) returning to the same or higher Tegner level. Subgroup analysis revealed three factors that independently affected RTP rate: (1) Players under 25 years had a higher rate of RTP (99.3% vs 90.2%. p = 0.001); (2) a subsequent operation prior to RTP decreased RTP rate from 98.2 to 89.7% (p = 0.009).; (3) undergoing meniscal surgery at ACL-R decreased RTP rate (p = 0.002). The mean time to RTP from surgery was 10.5 ± 3.6 months. Factors found to increase RTP time included age under 25 (11.0 vs 9.7 months, p = 0.005), recurrent effusions (11.4 vs 10.2 months, p = 0.035), and medial meniscal repair at ACL-R compared to meniscectomy (12.5 vs 9.6 months, p = 0.022). The surgical technique varied over the study period in relation to graft type, femoral tunnel position and addition of lateral extra-articular tenodesis (LET). Overall, the re-rupture rate was 8.2% at 2 years. Patella tendon autograft in an anteromedial bundle femoral tunnel position with addition of LET has the lowest re-rupture rate (2.0%).

CONCLUSION

Primary ACL-R in professional footballers yields high rates of RTP (96.1%), with 90.1% at the same level or higher, at a mean 10.5 months. Patients under 25 years not only had a significantly higher RTP rate, but also had a lengthier period of rehabilitation.

LEVEL OF EVIDENCE

Level IV.

Thigh muscle co-contraction patterns in individuals with anterior cruciate ligament reconstruction, athletes and controls during a novel double-hop test

Efficient neuromuscular coordination of the thigh muscles is crucial in maintaining dynamic knee stability and thus reducing anterior cruciate ligament (ACL) injury/re-injury risk. This cross-sectional study measured electromyographic (EMG) thigh muscle co-contraction patterns during a novel one-leg double-hop test among individuals with ACL reconstruction (ACLR; n = 34), elite athletes (n = 22) and controls (n = 24). Participants performed a forward hop followed by a 45° unanticipated diagonal hop either in a medial (UMDH) or lateral direction (ULDH). Medial and lateral quadriceps and hamstrings EMG were recorded for one leg (injured/non-dominant). Quadriceps-to-Hamstring (Q:H) ratio, lateral and medial Q:H co-contraction indices (CCIs), and medial-to-lateral Q:H co-contraction ratio (CCR; a ratio of CCIs) were calculated for three phases (100 ms prior to landing, initial contact [IC] and deceleration phases) of landing. We found greater activity of the quadriceps than the hamstrings during the IC and deceleration phases of UMDH/ULDH across groups. However, higher co-contraction of medial rather than lateral thigh muscles during the deceleration phase of landing was found; if such co-contraction patterns cause knee adduction, a putative mechanism to decrease ACL injury risk, during the deceleration phase of landing across groups warrants further investigation.

National Football League Wide Receivers and Running Backs Have Decreased Production Following ACL Reconstruction: An Evaluation of Fantasy Football Performance as an Outcome Measure

Purpose

To use fantasy football points as a simple measure alongside on-field statistics to compare performance in National Football League (NFL) offensive skill position players before and after anterior cruciate ligament (ACL) reconstruction.

Methods

A retrospective review of all NFL quarterbacks (QB), running backs (RB), wide receivers (WR), and tight ends (TE) who sustained an isolated, unilateral ACL injury from 1988 to 2017 was conducted. Data were collected from public data sources, team releases, NFL injury reports, press releases, and other Internet resources. For each player, a matched control with similar demographics was identified. Their in-game performance post-ACL reconstruction was analyzed using fantasy football points as an outcome measure.

Results

A total of 13 QBs, 30 RBs, and 29 WRs who underwent ACL reconstruction from 1988 to 2017 and who met inclusion criteria were retrospectively identified and reviewed. Of the 13 quarterbacks included in the study, there was no statistically significant difference in fantasy football points between the pre- and post-ACL reconstruction groups, as well as post-ACL and matched control groups. There was a statistically significant decrease in career fantasy football performance of running backs post-ACL reconstruction compared with matched control groups (129.6 vs 553.6; P < .0001). There was also a statistically significant decrease in per game fantasy football points post-ACL reconstruction (4.4 vs 11.2; P < .0001). Lastly, WRs also demonstrated a decrease in career fantasy football performance post-ACL reconstruction compared with matched controls (145.3 vs 460.9; P = .002). In addition, they also had a decrease in per game fantasy football performance (5.0 vs 7.7; P = .042).

Conclusions

Quarterbacks did not have a statistically significant decrease in performance following ACL reconstruction based on fantasy football performance. Conversely, both running backs and wide receivers had decreased per game and career performance post-ACL reconstruction based on their fantasy football statistics. Furthermore, RBs had the largest decline in production each season over a 3-year period following ACLR compared to QBs and WRs, respectively.

Level of Evidence

Level III, case-control study.

Return to Play and Performance After Anterior Cruciate Ligament Reconstruction in National Football League Players

Background:

Considerable variability exists in return-to-play rates after anterior cruciate ligament (ACL) injury and reconstruction (ACLR) among National Football League (NFL) players of different positions.

Purpose/Hypothesis:

The purpose of this study was to compare return-to-play and performance levels by position in NFL players after ACLR. It was hypothesized that (1) ACL injuries have significant effects on the careers of NFL players, including return to play and performance, and (2) players of certain positions that involve relatively less pivoting and cutting perform better after ACLR.

Study Design:

Descriptive epidemiology study.

Methods:

All NFL players who underwent ACLR between 2013 and 2018 were identified using the FantasyData injury database. Player characteristics, snap count, games played, games started, and performance metrics were collected for 3 years before and after injury using the Pro Football Reference database. Performance was measured using an approximate value (AV) algorithm to compare performance across positions and over time. Nonparametric tests were used to compare the pre- and postinjury data and the percentage change in performance between different positions.

Results:

Overall, 312 NFL players were included in this study, and 174 (55.8%) returned to play. Of the eligible players, only 28.5% (n = 59/207) remained in the league 3 years postinjury. Within the first 3 years postinjury, players played in fewer games (8.7 vs 13.7; P < .0001), started in fewer games (3.0 vs 8.3; P < .0001), had lower AVs (1.5 vs 4.3; P < .0001), and had decreased snap counts (259.0 vs 619.0; P < .0001) compared with preinjury. Quarterbacks were most likely to return to play (92.9% vs 53.7%; P = .0040) and to return to performance (2% vs 50% decrease in AV; P = .0165) compared with the other positions. Running backs had the largest decrease in AV (90.5%), followed by defensive linemen (76.2%) and linebackers (62.5%).

Conclusion:

The study findings indicated that NFL players are severely affected by ACL injury, with only 28.5% still active in the league 3 years after the injury. Running backs, defensive linemen, and linebackers performed the worst after injury. Quarterbacks were most likely to return to play and had superior postinjury performance compared with the other positions.

ACL Tears in the National Football League From 2013 to 2020: Analysis of the 2020 Season After Delays and Schedule Changes From the Early COVID-19 Pandemic Relative to Prior Seasons

Background:

The impact of fatigue and preseason preparation on anterior cruciate ligament (ACL) tears in the National Football League (NFL) are not well described. The 2020 NFL season did not include the standard preseason in response to changes secondary to the coronavirus disease-2019 (COVID-19) pandemic.

Purpose:

To evaluate the association of game play on ACL tears in NFL athletes and to determine if differences in ACL tear epidemiology were present based on season of play from 2013 to 2020.

Study Design:

Descriptive epidemiology study.

Methods:

ACL tears in NFL athletes were identified using publicly available data. Games played and snap counts at the time of injury were recorded for each athlete sustaining game-related injuries. Tear rates were determined, and injuries were also calculated per 1000 athlete-exposures. Incidence rate ratios (IRRs) with 95% confidence intervals (CIs) were calculated.

Results:

Overall, 379 ACL tears were identified, including 256 (67.6%) during game play and 118 (31.1%) during practice. Practice-based injuries were significantly higher in the preseason versus the remainder of the season. Games and snaps at the time of injury did not differ by year. The incidence rate of preseason injuries was significantly greater relative to in-season injuries (IRR = 2.68; 95% CI, 2.18-3.29; P < .00001). There was an elevated incidence rate of in-season injuries in 2020 relative to 2014-2019 combined (IRR = 1.49; 95% CI, 0.98-2.19; P = .048). In 2013 to 2019, the most frequent month of injury was the first month of the preseason in August (119/334 tears; 35.6%), whereas in 2020, the most frequent month was September (13/41 tears, 31.7%). The proportion of tears in September 2020 was not different from the proportion of tears in August 2013 to 2019.

Conclusion:

There was an increased proportion of in-season ACL tears in the 2020 NFL season relative to 2014 to 2019; this is attributable to a frameshift in the consistent trend of injuries in the 1st month to return of competitive play, with 2020 being in the regular season in September as opposed to the preseason in August.

Lower extremity injuries in the baseball athlete

Baseball is unique in its multiple facets: pitching, hitting, base rounding, and fielding are distinct activities that require different athletic skills to perform at a high level. Likewise, these different aspects of the game can contribute to a multitude of varying injuries. While high-velocity overhead throwing, along with batting, can produce a plethora of upper extremity injuries that often garner attention, injuries to the lower extremity can severely impact a player’s performance and ability to compete. The rigors of the short, explosive sprinting required for base running, as well as the dynamic movement required for fielding, create ample opportunity for lower limb injury, and even subtle pathology can affect a pitcher’s ability to perform or increase their long-term risk of injury. Chronic injury from conditions such as femoroacetabular impingement and hip labral tears can also occur. The purpose of the present review is to summarize the relevant epidemiology, pathophysiology, and treatment of lower extremity injuries in baseball athletes, with reference to current research into the prevention and management of such injuries.

High Return to Play and Low Reinjury Rates in National Collegiate Athletic Association Division I Football Players Following Anterior Cruciate Ligament Reconstruction Using Quadrupled Hamstring Autograft

PURPOSE

The purpose of this study was to examine the outcomes of anterior cruciate ligament (ACL) reconstruction using quadrupled hamstring (QH) autograft in a cohort of National Collegiate Athletic Association (NCAA) Division I football players.

METHODS

A retrospective analysis was performed on NCAA Division I football players at a single institution who had transtibial ACL reconstruction using QH autograft between 2001 and 2016. Primary outcomes were ACL reinjury and return to play (RTP). Secondary outcomes were position, percent of eligibility used after surgery, graft diameter, Tegner-Lysholm scores, concomitant injuries/surgeries, and postcollegiate professional play.

RESULTS

Between 2001 and 2016, 34 players had QH autograft ACL reconstruction, and 29 players achieved RTP. Of the 29, 2 (6.9%) sustained ACL reinjuries. The average RTP was 318 days (range 115-628) after surgery. Players used 79.5% of their remaining collegiate eligibility after surgery. Nine players sustained multiligamentous knee injuries. This did not have a significant effect on RTP (P = 0.709; mean 306±24 days for isolated ACL, mean of 353±51 for 2 ligaments, mean of 324±114 for 3 + ligaments) and none sustained reinjury. Associated meniscal injuries were sustained by 28, and 8 sustained chondral injuries. The mean postoperative Tegner-Lysholm score was 90.7 of 100, with mean follow-up of 102 months. Of these players, 18 went on to play professionally, with 17 joining National Football League rosters and 1 an arena team roster.

CONCLUSION

QH demonstrated an ACL reinjury and RTP rates similar to those in previously published, predominantly bone-patella tendon-bone ACL reinjury data in elite athletes. This study demonstrates that QH autograft may be a viable option in elite athletes.

LEVEL OF EVIDENCE

IV, case series.

ACL Reconstruction Rehabilitation: Clinical Data, Biologic Healing, and Criterion-Based Milestones to Inform a Return-to-Sport Guideline

CONTEXT

Anterior cruciate ligament (ACL) reconstruction (ACLR) and postoperative rehabilitation continues to be a multidisciplinary focus in both research and clinical environments. Recent research on ACLR warrants a reexamination of clinicians' current rehabilitation practices to optimize the strikingly variable clinical outcomes after ACLR and return to sport. The purpose of the article and updated guidelines is to use contemporary evidence to systematically revisit our practice guidelines and validate our clinical milestones with data from our university-based practice.

EVIDENCE ACQUISITION

Using the PubMed search engine, articles that reported on ACLR rehabilitation and protocols, guidelines, graft type, healing and strain, return to sport, psychological considerations, and secondary injury prevention published from 1979 to 2020 were identified using the search terms ACLR protocols, guidelines, ACLR rehabilitation, ACL graft, ACL open kinetic chain (OKC) exercise and closed kinetic chain (CKC) exercise, ACLR return to sport, ACLR psychological factors, and ACL injury prevention.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 5.

RESULTS

Clinical milestones after ACLR were validated using clinical data collected from 2013 to 2017 at a university-based practice. Variables including knee joint range of motion, effusion, Knee Outcome Survey-Activities of Daily Living Scale, and quadriceps strength index were tracked throughout rehabilitation and analyzed to help inform an updated ACLR rehabilitation guideline.

CONCLUSION

Incorporating the latest research, combined with direct clinical data, provides a current, realistic, and clinically benchmarked strategy for ACLR rehabilitation. Commonly held clinical beliefs regarding rehabilitation after ACL injury must be challenged by the latest research to improve patient outcomes and decrease the risk of reinjury. Key updates to the practice guidelines include the use of frequent and accurate quadriceps strength testing, delayed return-to-sport timeline, immediate use of open kinetic chain exercise, criterion-based progressions for running, sprinting, plyometrics, agility, cutting/pivoting, return to competition, and the inclusion of a secondary prevention program after return to sport.

STRENGTH OF RECOMMENDATION TAXONOMY (SORT)

B.

Anterior Cruciate Ligament Reconstruction: Is Biological Augmentation Beneficial?

Surgical reconstruction in anterior cruciate ligament (ACL) ruptures has proven to be a highly effective technique that usually provides satisfactory results. However, despite the majority of patients recovering their function after this procedure, ACL reconstruction (ACLR) is still imperfect. To improve these results, various biological augmentation (BA) techniques have been employed mostly in animal models. They include: (1) growth factors (bone morphogenetic protein, epidermal growth factor, granulocyte colony-stimulating factor, basic fibroblast growth factor, transforming growth factor-β, hepatocyte growth factor, vascular endothelial growth factor, and platelet concentrates such as platelet-rich plasma, fibrin clot, and autologous conditioned serum), (2) mesenchymal stem cells, (3) autologous tissue, (4) various pharmaceuticals (matrix metalloproteinase-inhibitor alpha-2-macroglobulin bisphosphonates), (5) biophysical/environmental methods (hyperbaric oxygen, low-intensity pulsed ultrasound, extracorporeal shockwave therapy), (6) biomaterials (fixation methods, biological coatings, biosynthetic bone substitutes, osteoconductive materials), and (7) gene therapy. All of them have shown good results in experimental studies; however, the clinical studies on BA published so far are highly heterogeneous and have a low degree of evidence. The most widely used technique to date is platelet-rich plasma. My position is that orthopedic surgeons must be very cautious when considering using PRP or other BA methods in ACLR.

Preseason elimination impact on anterior cruciate ligament injury in the National Football League

BACKGROUND

Anterior cruciate ligament (ACL) injuries represent detrimental injuries in the National Football League (NFL). A significant portion of these injuries often occur in preseason exhibitions. The Coronavirus disease 2019 pandemic presented a unique disruption to preseason NFL football with the cancelation of all preseason games.

AIM

To compare the incidence of ACL tears through the first eight weeks of the NFL season in 2020 to the mean incidence over the previous 5 seasons (2015-2019) and determine if there was any change in incidence with the elimination of the preseason.

METHODS

NFL players who suffered ACL tears during the preseason and first eight weeks of the NFL season from 2015-2020 were identified. The number of ACL injuries for the 2015-2019 seasons was compared to the 2020 season for four different timeframes. For each analysis, the cumulative number of ACL injuries to that time point was used to calculate the percent difference for descriptive analysis. Additionally, the number of teams with at least one player suffering an ACL tear were identified and compared using Chi-Squared testing. Finally, a cumulative relative risk was calculated for each week played.

RESULTS

There were 14 ACL tears through the first four games of the 2020 season, a 118.8% (14 vs 6.4) increase in comparison to the 5-year average over the first 4 regular season weeks of 2015-2019. However, when accounting for injuries occurring during the preseason from 2015-2019, there were 18.6% (14 vs 17.2) fewer total ACL injuries through regular season week 4 with no significant difference in percentage of teams impacted when these preseason injuries were accounted for P = 0.394. Results were similar (19 vs 17.2) over 8 total games played (whether regular season or preseason), and over 8 regular season games (P = 0.196, P = 0.600).

CONCLUSION

The elimination of the NFL preseason resulted in a higher rate of injuries during the first 4 games of the regular season. However, these increases are offset by the injuries typically sustained during the preseason. This suggests there may be front-loading of injuries over the course of an NFL season, such that players may be more prone to injury when the intensity of play suddenly increases, whether in the preseason or regular season.

Factors Associated With the Mechanism of ACL Tears in the National Football League: A Video-Based Analysis

Background

The factors associated with anterior cruciate ligament (ACL) injury mechanism in professional American football players are not well-understood.

Hypothesis

It was hypothesized that football-related and player-specific factors, such as position and body mass index (BMI), are associated with ACL injury mechanism in these athletes.

Study Design

Descriptive epidemiology study.

Methods

Videos of ACL tears occurring in National Football League (NFL) games over 6 consecutive seasons from 2014 to 2019 were reviewed by 2 orthopaedic surgeons who specialize in sports medicine. For each injury, the role of contact (direct contact [contact to the injured knee/lower extremity], indirect contact [contact not involving the injured knee/lower extremity], or no contact) as well as playing situation and lower extremity position were recorded. Additional player characteristics, timing of injury, and surface information were obtained from NFL game-day and injury database statistics.

Results

Of the 140 ACL tears, a minority occurred via direct contact to the injured lower extremity (30%), although this varied by position. Just over two-thirds (70%) of ACL tears in offensive linemen occurred via direct contact to the injured lower extremity, while wide receivers had no direct contact ACL tears. Elevated BMI was associated with a greater likelihood of ACL tears occurring via direct contact (53% in players with BMI ≥35 kg/m² vs 24% in players with BMI <35 kg/m²; P = <.01). Rookies had the lowest percentage of direct contact ACL tears (18%; P = .22). ACL tears that occurred during the middle 8 weeks of the regular season resulted more often from direct contact (38%; P = .06). ACL tears that occurred in the third quarter were the most likely to occur via direct contact (44%), while those that occurred in the fourth quarter were the least likely to occur via direct contact (13%; P < .01).

Conclusion

Although most NFL players sustained ACL tears via a noncontact mechanism (ie, through indirect or no contact), players with an elevated BMI, especially on the offensive line, were more likely to injure their ACL through direct contact. Position-dependent variance in injury mechanism may help guide injury prevention efforts in these athletes.

Game Utilization and Performance Following RTP From ACL Reconstruction Does not Influence a Subsequent Second ACL Injury in National Football League Players

Purpose

The purpose of this study is to evaluate differences in game utilization or performance following primary anterior cruciate ligament (ACL) reconstruction between National Football League (NFL) players with and without a second ACL injury.

Methods

NFL players who underwent ACL reconstruction between 2013 and 2017 were identified. Players were classified as having one injury (“tear”) or having later sustained a subsequent second (reinjury or contralateral) ACL injury (“retear”). Players were excluded if they tore their ACL prior to the NFL, did not return to play (RTP), did not play the season before injury, or had concomitant injuries. Demographic characteristics, game utilization statistics, and season approximate value (SAV) performance metrics were recorded. Statistical analysis compared data after RTP from primary ACL reconstruction (seasons +1, +2, and +3) relative to the season before injury (season −1) between cohorts using mean differences and relative percentages.

Results

Analysis included a total of 45 players, 32 in the “tear” group and 13 in the “retear” group. Demographics, level of play, and time to RTP after primary ACL reconstruction did not differ between the groups (P > .05). Tear and retear groups demonstrated similar utilization and performance metrics the season prior to injury (−1) and the 3 seasons following RTP (season of injury is “0”). Both groups had a similar decrease (relative percentage) in games played and started, snap counts, and SAV during the 3 seasons following RTP compared to baseline (P > .05). The draft pick position was correlated with the relative percentage of games started the first season after RTP (r = .6, P = .02).

Conclusions

Game utilization and performance metrics following ACL reconstruction were not associated with a subsequent second ACL injury. Players with a higher draft pick position were more likely to return to the starting lineup following primary ACL reconstruction. Ultimately, player game utilization and performance following primary ACL reconstruction is not predictive of a subsequent second ACL injury.

Level of Evidence

Level III, retrospective case-control study

ACL Study Group survey reveals the evolution of anterior cruciate ligament reconstruction graft choice over the past three decades

PURPOSE

Anterior cruciate ligament reconstruction (ACLR) aims to restore knee function and stability, allowing patients to return to the activities they enjoy and minimize further injury to the meniscus and cartilage and their ultimate progression to osteoarthritis. This study aims to present the evolution of graft choice over the last three decades according to members of the ACL Study Group (SG).

METHODS

Prior to the January 2020 ACL SG biannual meeting, a survey was administered consisting of 87 questions and 16 categories, including ACLR graft choice. A similar questionnaire has been administered prior to each meeting and survey results from the past 14 meetings (1992 through 2020, excluding 1994) are included in this work. Survey responses are reported as frequencies in percentages to quantify changes in practice over the surgery period.

RESULTS

In 1992, the most frequent graft choice for primary ACLR was bone-patellar tendon-bone (BTB) autograft, at nearly 90%. Hamstring tendon (HT) autografts have increased in popularity, currently over 50%, followed by just under 40% BTB autograft. Recently, quadriceps tendon (QT) autograft has increased in popularity since 2014.

CONCLUSION

Autograft (HT, BTB, QT) is an overwhelming favorite for primary ACLR over allograft. The preference for HT autograft increased over the study period relative to BTB autograft, with QT autograft gaining in popularity in recent years. Graft selection should be individualized for each patient and understanding the global trends in graft choice can help orthopaedic surgeons discuss graft options with their patients and determine the appropriate graft for each case.

LEVEL OF EVIDENCE

Level V, Expert Opinion.

ACL Study Group presents the global trends in ACL reconstruction: biennial survey of the ACL Study Group

OBJECTIVES

The primary objective of this survey was to gauge the current global trends in anterior cruciate ligament reconstruction (ACLR) as reported by the members of the Anterior Cruciate Ligament (ACL) Study Group (SG).

METHODS

A survey was created and distributed among the members of the ACL SG consisting of 87 questions and 16 categories related to ACLR, including member demographics, preoperative management, primary ACLR techniques and graft choice, use of concomitant procedures and biological augmentation, postoperative rehabilitation, and more.

RESULTS

The survey was completed by the 140 members of the ACL SG. Fifty per cent of members are from Europe, 29% from the USA, 15% from the Asia-Pacific and the remaining 6% are from Latin America, the Middle East, New Zealand and Africa. Most (92%) do not believe there is a role for non-operative management of ACL tears in higher level athletes; conversely, most agree there is a role for non-operative management in lower impact athletes (92%). A single-bundle (90%) technique with hamstring autograft (53%) were most common for primary ACLR. Tunnel position varied among respondents. Sixty-one per cent do not use allograft for primary ACLR. Fifty per cent of respondents use cortical suspensory fixation on the femur, with variable responses on the tibia. Most (79%) do not use biologics in primary ACLR, while 83% think there is a selective role for extra-articular augmentation in primary ACLR. Fifty per cent prefer bone-tendon-bone autograft for revision ACLR and extra-articular augmentation is more commonly used (13% always, 26% often) than in primary ACLR (0% always, 15% often). A majority (53%) use a brace after primary ACLR. The most common responses for minimal time to return to play after primary ACLR were 6-8 months (44%) and 8-12 months (41%).

CONCLUSION

We presented the thoughts and preferences of the ACL SG on the management of ACL injuries. This survey will help to facilitate an ongoing discussion with regard to ACLR by providing global insights into the current surgical trends in ACLR.

LEVEL OF EVIDENCE

Level V, Expert Opinion.

Sport activity levels following ankle fusion

PURPOSE

Ankle arthrodesis (AA) is frequently employed in the treatment of end-stage ankle arthritis, which is common following trauma and athletic injuries. While AA remains a popular therapeutic option, little data exists about activity and sporting capacity following AA. The objective of this research was to determine functional outcomes and sporting activity levels in patients following Ankle Arthrodesis.

METHODS

Validated questionnaires were emailed to 35 patients with a history of AA at an average follow-up of 52 months. Functional outcomes were assessed using the Foot and Ankle Disability Index (FADI), as well as the associated FADI-Sport. Responses were compared to those from a control population of RESULTS: 24 patients scheduled for AA, at an average pre-operative visit of three months. Activity levels were assessed prior to injury as well as pre- and post-operatively using the Tegner activity level scale. Average Tegner scores of the 35 surgical patients decreased from 3.82 ± 0.38 before their injury, to 1.15 ± 0.19 immediately pre-op, with recovery to 2.67 ± 0.26 following fusion. Average post arthrodesis FADI and FADI-sport scores in our patients were 76.5 ± 3.19% and 33.8 ± 23.06%. For the pre-operative control population, corresponding scores were 47.41 ± 2.61% and 22.24 ± 1.03%. Following AA, we found that patients improved upon their pre-op Tegner score, although they did not return to their pre-injury level of sporting participation. Additionally, patients reported that they had no current dysfunction with their lower leg.

CONCLUSION

Patients undergoing Ankle Arthrodesis should expect improved lower leg function, though will not likely return to their pre-injury level of activity.

The Non-injured Leg Can Be Used as a Reference for the Injured Leg in Single-legged Hop Tests

BACKGROUND

Single-legged hop tests are frequently used in substantiating return to sport decisions following lower extremity injury. Evidence for using the non-injured leg as a reference for the injured leg in the return to sport decision-making at the criterion-based point of return to sport following lower extremity injury is lacking.

PURPOSE

To compare absolute values in single-legged hop tests between the non-injured leg of athletes returning to high-impact sports after lower extremity injury and the matched leg of healthy athletes.

STUDY DESIGN

Cross-sectional study.

METHODS

One hundred and sixty-nine athletes returning to high-impact sports after lower extremity injury and 169 matched healthy athletes executed five single-legged hop tests. Differences between athletes returning to high-impact sports after lower extremity injury and matched healthy athletes on five single-legged hop tests were analyzed using paired t-tests.

RESULTS

There were no statistically significant differences between the non-injured leg of athletes returning to sport and the matched leg of healthy athletes. Effect sizes ranged from 0.05 to 0.14 indicating negligible effects.

CONCLUSION

Clinicians can use the non-injured leg as a reference for the injured leg in single-legged hop tests for deciding on return to high-impact sports after lower extremity injuries.

LEVEL OF EVIDENCE

3b.

Epidemiology of Anterior Cruciate Ligament Tears in the National Football League

BACKGROUND

Anterior cruciate ligament (ACL) tears are common in contact athletics and have a significant effect on the athletic performance and well-being of affected players. The prevalence, timing, and characteristics of ACL tears in National Football League (NFL) athletes are lacking.

PURPOSE

To define the epidemiology of ACL tears among NFL athletes.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

This retrospective study includes all ACL injuries entered into the NFL injury database through the centralized leaguewide electronic health record system for the 2015-2019 seasons.

RESULTS

A total of 314 ACL injuries occurred during the 5-year study period, with a mean of 62 per year. The overall 1-season injury risk of an NFL player sustaining an ACL injury was 1.9% (95% CI, 1.7%-2.1%). Most ACL injuries occurred during games (n = 199), with a higher rate observed in the preseason games as compared with the regular season games (6.1 vs 2.7 per 10,000 player-plays; P < .01). NFL players with ≤3 of experience had a higher preseason injury rate (9.57 ACL tears per 1000 player-seasons) than those with ≥4 years of experience (5.12 ACL tears per 1000 player-seasons; P < .01). NFL athletes playing on special teams had the highest rate of ACL injuries (7.6 per 10,000 player-plays) in comparison with all other player positions.

CONCLUSION

ACL injury incidence was fairly consistent across all years studied and occurred more frequently in players with ≤3 years of NFL experience. Tears were more common during games, special teams play, and the preseason.

Decreased Performance and Return to Play Following Anterior Cruciate Ligament Reconstruction in National Football League Wide Receivers

Purpose

To identify the time to return to play (RTP) and evaluate the performance level in wide receivers in the National Football League following anterior cruciate ligament (ACL) reconstruction.

Methods

A total of 29 wide receivers in the National Football League who underwent ACL reconstruction between 2013 and 2017 who met inclusion criteria were retrospectively identified and reviewed. For each player, a matched control with similar demographics was identified to compare various in-game performance measurements and seasons played.

Results

Of the wide receivers that met the inclusion criteria, 9 of 29 (31%) did not RTP in a regular season game following ACL reconstruction. For players who did RTP, 20 of 29 (69%), the average time was 10.9 months (331.4 ± 41.6 days). When we compared the tear group with the matched control cohort, players with ACL tears ended their careers on an average of 1.9 seasons earlier (2.2 vs 4.1 seasons, P < .001) and also played less than half the number of games (25.5 vs 56.6 games, P = .001), respectively. Those that RTP also saw decreased performance statistics in targets (353.6 vs 125.2 P < .001), receptions (208.0 vs 74.4, P = .001), receiving yards (2691.0 vs 987.9, P = .001), and touchdowns (17.4 vs 6.2, P = .002).

Conclusions

Sixty-nine percent of wide receivers who underwent ACL reconstruction were able to RTP at an average of 10.9 months, or 331.4 days. Despite the majority of players being able to RTP, there was a significant decrease in both statistical performance and career duration.

Level of Evidence

Level III, case-control study.

Patient-reported evaluation on giving way is important for return to preinjury activity level after Anterior Cruciate Ligament reconstruction

PURPOSE

The present study evaluated the rate of returning to the preinjury level of competitive sports after ACLR and influential factors.

METHODS

After excluding composite ligament injury cases, 96 patients with a Tegner activity score of ≥ 6 who were managed between April 2015 and March 2016 and had been followed for ≥ 2 years were included in the present study. The patients were evaluated for instability, and the following data were collected: second-look arthroscopy findings, muscle strength, and International Knee Documentation Committee (IKDC) subjective score (follow-up rate: 88.1%).

RESULTS

The rate of returning to the preinjury level of competitive sports was 62/96 (64.6%). Only the total IKDC subjective score (odds ratio, 1.052; 95% confidence interval 1.004-1.102; p = 0.035) and the subjectively evaluated item about giving way (odds ratio, 1.762; 95% confidence interval 1.066-2.911; p = 0.027) were independently associated with the returning to the preinjury level of competitive sports after ACLR in the logistic regression analysis.

CONCLUSION

The rate of returning to the preinjury level of competitive sports after ACLR was 64.6%, even if a good knee stability and healing status of the sutured meniscus were acquired after ACLR. The IKDC subjective score, especially the item about giving way, was significantly associated with the returning to the preinjury level of competitive sports. The factors assessed by patient-reported evaluations concerning giving way that may be related to functional performance, including brain activity, are important to consider to improve the rate of returning to the preinjury level of competitive sports.

LEVEL OF EVIDENCE

III.

Anterior Cruciate Ligament Injuries in Australian Rules Football: Incidence, Prevention and Return to Play Outcomes

Australian Rules football is the most popular of the various codes of football played in Australia. During the game players perform frequent landing, cutting and pivoting manoeuvres that expose them to substantial risk for anterior cruciate ligament (ACL) injury. Recent years have seen the introduction of a professional women's league that has resulted in an exponential growth in the participation of women and girls in this sport. Unfortunately, there is a corresponding growth in ACL injury rates in female players. This review summarizes the incidence of ACL injury in both men's and women's Australian Rules football and reviews potential causative factors and risk reduction strategies. The final section takes an in depth look at return to sport outcomes after ACL reconstruction surgery in these populations. Whilst an ACL injury does not mean the end of a player's career in Australian football, it certainly presents a significant challenge in terms of return to preinjury levels of form and high rates of secondary and tertiary ACL injury are also a significant concern.

Return to sport after anterior cruciate ligament injury: Panther Symposium ACL Injury Return to Sport Consensus Group

OBJECTIVES

A precise and consistent definition of return to sport (RTS) after anterior cruciate ligament (ACL) injury is lacking, and there is controversy surrounding the process of returning patients to sports and their previous activity level. The aim of the Panther Symposium ACL Injury RTS Consensus Group was to provide a clear definition of RTS after ACL injury and description of the RTS continuum, as well as provide clinical guidance on RTS testing and decision-making.

METHODS

An international, multidisciplinary group of ACL experts convened as part of a consensus meeting. Consensus statements were developed using a modified Delphi method. Literature review was performed to report the supporting evidence.

RESULTS

Key points include that RTS is characterised by achievement of the preinjury level of sport and involves a criteria-based progression from return to participation to RTS, and ultimately return to performance. Purely time-based RTS decision-making should be abandoned. Progression occurs along an RTS continuum with decision-making by a multidisciplinary group that incorporates objective physical examination data and validated and peer-reviewed RTS tests, which should involve functional assessment as well as psychological readiness. Consideration should be given to biological healing, contextual factors and concomitant injuries.

CONCLUSION

The resultant consensus statements and scientific rationale aim to inform the reader of the complex process of RTS after ACL injury that occurs along a dynamic continuum. Research is needed to determine the ideal RTS test battery, the best implementation of psychological readiness testing and methods for the biological assessment of healing and recovery.

Return to Sport After Anterior Cruciate Ligament Reconstruction in a Cohort of Division I NCAA Athletes From a Single Institution

Background:

Anterior cruciate ligament (ACL) tears are common in collegiate athletes. The rate of return to the preinjury level of sport activities after ACL reconstruction continues to evolve.

Purpose/Hypothesis:

The purpose was to determine the return-to-sport rate after ACL reconstruction in a cohort of National Collegiate Athletic Association Division I athletes in different sports. It was hypothesized that, with intensive supervision of rehabilitation, the return-to-sport rate would be optimal.

Study Design:

Case series; Level of evidence, 4.

Methods:

We retrospectively reviewed the records of 75 collegiate athletes from a single institution who had undergone unilateral or bilateral ACL reconstruction between 2001 and 2013 and participated in an extensive supervised rehabilitation program. Prospectively collected athlete data as well as data about preinjury exposure, associated lesions, surgical technique, time lost to injury, number of games missed, time to return to full sport activity or retire, and subsequent surgical procedures were extracted from the medical and athletic trainer records.

Results:

The 75 patients (40 male, 35 female; mean age, 20.1 years) underwent 81 reconstruction procedures (73 primary, 8 revision). The mean follow-up was 19.3 months. The overall return-to-sport rate was 92%. After reconstruction, 9 athletes (12%) retired from collegiate sports, but 3 of them returned to sport activities after graduation. Overall, 8 athletes (11%) experienced an ACL graft retear.

Conclusion:

The return-to-sport rate in our National Collegiate Athletic Association Division I athletes compared favorably with that reported in other studies in the literature. The strict follow-up by the surgeon, together with the high-profile, almost daily technical and psychological support given mainly by the athletic trainers during the recovery period, may have contributed to preparing the athletes for a competitive rate of return to sport at their preinjury level.

Professional Athlete Return to Play and Performance After Shoulder Arthroscopy Varies by Sport

Purpose

To determine whether differences in return-to-play (RTP) rate and performance-based outcomes exist following shoulder arthroscopy in athletes from the National Football League (NFL), National Basketball League (NBA), Major League Baseball (MLB), and National Hockey League (NHL).

Methods

Professional athletes from the NFL, NBA, MLB, and NHL who underwent shoulder arthroscopy between January 1998 and December 2016 were identified through an established review of injury reports and public archives. Sport-specific statistics were collected before and after shoulder arthroscopy for each athlete, providing a performance score. RTP was defined as the first game played postsurgery.

Results

Of the 208 professional athletes who met the inclusion criteria, 167 (80.3%) returned to play following shoulder arthroscopy, with MLB players returning at a significantly lower rate than those of other sports (P < .0001). NBA players had significantly shorter recovery times (201 days; P < .01) and MLB players had significantly longer recovery times (413 days; P < .001) when compared with athletes in other sports. The mean number of seasons played after shoulder arthroscopy was 3.7, 4.7, 4.8, and 5.8 for MLB, NFL, NHL, and NBA, respectively. NBA players performed worse in their first season postoperative compared with their preoperative performance (P = .0017), but their postoperative season 2 performance returned to their preoperative performance level (P = .1893). Similarly, NHL players performed worse in their postoperative season 1 compared with preoperative performance (P = .0274), but their postoperative season 2 performance improved upon their preinjury performance level (P = .0861).

Conclusions

There is a modest RTP rate among professional athletes following shoulder arthroscopy. MLB players have the longest average time to RTP and the shortest postinjury careers following shoulder arthroscopy. However, they demonstrate no significant decline in performance following their injury. Conversely, NBA players had the shortest average time to RTP and the longest post-injury career. Both NBA and NHL athletes experienced a decrease in performance in post-operative season one.

Level of Evidence

Level III, retrospective comparative study.

Musculoskeletal Injury History Is Associated With Lower Physical and Mental Health in a Historical Cohort of Former National Football League Players

CONTEXT

Little research has examined health-related quality of life in former National Football League (NFL) players.

OBJECTIVE

Examine the association of musculoskeletal injury history and current self-reported physical and mental health in former NFL players.

SETTING

Cross-sectional questionnaire.

PATIENTS OR OTHER PARTICIPANTS

Historical cohort of 2,103 former NFL players that played at least one season between 1940 and 2001.

INTERVENTION

Players were grouped by self-reported professional career musculoskeletal injury history and whether injuries affected current health: (1) no musculoskeletal injury history; (2) musculoskeletal injury history, currently affected by injuries; and (3) musculoskeletal injury history, not currently affected by injuries.

MAIN OUTCOME MEASURE

The Short Form 36 Measurement Model for Functional Assessment of Health and Well-Being (SF-36) yielded physical and mental health composite scores (PCS and MCS, respectively); higher scores indicated better health. Multivariable linear regression computed mean differences (MD) among injury groups. Covariates included demographics, playing history characteristics, surgical intervention for musculoskeletal injuries, and whether injury resulted in premature end to career. MD with 95% CI excluding 0.00 were deemed significant.

RESULTS

Overall, 90.3% reported at least one musculoskeletal injury during their professional football careers, of which 74.8% reported being affected by their injuries at time of survey completion. Adjusting for covariates, mean PCS in the "injury and affected" group was lower than the "no injury" (MD = -3.2; 95% CI: -4.8, -1.7) and "injury and not affected" groups (MD = -4.3; 95% CI: -5.4, -3.3); mean MCS did not differ.

CONCLUSION

Many players reported musculoskeletal injuries, highlighting the need for developing and evaluating injury management interventions.

Return to Play Rates in NFL Wide Receivers and Running Backs After ACL Reconstruction: An Updated Analysis

Background:

Anterior cruciate ligament (ACL) ruptures are potentially career-threatening injuries to National Football League (NFL) skill position players. A 2006 study showed a return-to-play (RTP) rate of 79% for NFL running backs (RBs) and wide receivers (WRs). Since then, a number of factors affecting RTP, including style of play as well as rules regarding hits to the head, have changed how defensive players tackle offensive ball carriers.

Purpose/Hypothesis:

To determine whether the RTP rate for RBs and WRs in the NFL has changed since data were collected in the 2000s. Additionally, we evaluated player performance before and after ACL reconstruction (ACLR). We hypothesized that there will be a lower RTP rate than previously reported as well as a decrease in performance statistics after ACLR.

Study Design:

Descriptive epidemiology study.

Methods:

Publicly available NFL injury reports between the 2009-2010 and 2015-2016 seasons were utilized for RBs and WRs who underwent ACLR. Successful RTP was indicated by playing in at least 1 NFL game after reconstruction. Position-specific performance statistics from before and after reconstruction were gathered for these players, and the RTP players were compared against the players who did not RTP (dnRTP group). Pre- and postinjury performance measures were also compared against a matched control group of NFL RBs and WRs who had not sustained an ACL injury.

Results:

Overall, 61.8% of players (64.5% of RBs, 60% of WRs) returned to play at a mean of 13.6 months. Prior to injury, the RTP group had played in significantly more career games and had significantly more rushes and receptions per game than the dnRTP group; however, there was no significant difference in performance after ACLR. The WR RTP group had significantly decreased performance in all measured categories when compared with the control group.

Conclusion:

Our study found a lower RTP rate in RBs and WRs than previous studies conducted in the early 2000s. WRs who achieved RTP had decreased performance when compared with noninjured controls.

Return to Sport and Reinjury Rates in Elite Female Athletes After Anterior Cruciate Ligament Rupture

While there has been significant interest in the documentation of return to sport outcomes following anterior cruciate ligament (ACL) injury, the elite level female athlete has not been a focus of this research. This is despite women being at increased risk for ACL injury and considerable global growth in women participating in sport. Therefore, the focus of this review was to examine the available literature regarding return to sport outcomes in elite level women with an ACL injury. The topics of discussion focus on return to sport rates, timing and determinants of return to sport, longevity of play, return to sport performance, and further ACL injury. Knee health in the longer term is also briefly discussed along with the limitations of the existent literature.

Quadriceps strength to body weight ratio is a significant indicator for initiating jogging after anterior cruciate ligament reconstruction

BACKGROUND

Quadriceps strength recovery after anterior cruciate ligament (ACL) reconstruction is an important criterion for progress in rehabilitation and return to sports. The purpose of this study was to determine whether quadriceps strength to body weight ratio (QS/BW) is a significant indicator for initiating jogging after ACL reconstruction.

METHODS

Isokinetic quadriceps strength at 60°/s was measured and a jogging trial was completed 3 months after ACL reconstruction with hamstring tendon autograft in 83 patients (36 male, 47 female; mean age, 26.6 ± 12.4 years). Based on the jogging trial results, patients were assigned to either a successful jogging group (mean velocity ≥ 9 km/h) or an unsuccessful jogging group (mean velocity < 9 km/h). The association between QS/BW and successful jogging after surgery was investigated by multivariate logistic regression analysis and the cut-off value was determined by receiver operating characteristic analysis.

RESULTS

Forty-four patients (53.0%) were assigned to the successful jogging group and 39 (47.0%) to the unsuccessful jogging group. QS/BW was independently associated with initiating jogging 3 months after surgery. The cut-off value of QS/BW for successful jogging was 1.45 Nm/kg (area under the curve = 0.94; sensitivity = 88.6%, specificity = 87.2%). All of the patients who initiated jogging with QS/BW of > 1.45 Nm/kg at 3 months returned to sports without recurrence or contralateral injury by 10 months after surgery.

CONCLUSIONS

QS/BW is a significant indicator for safely initiating jogging 3 months after ACL reconstruction. The cut-off value of QS/BW for initiating jogging was 1.45 Nm/kg.

Performance Outcomes and Return-to-Sport Rate of National Hockey League Athletes Vary After Common Orthopedic Surgical Procedures

OBJECTIVE

Evaluate performance-based outcomes and return-to-sport rate in National Hockey League (NHL) athletes.

DESIGN

Retrospective cohort study.

SETTING

Public records. No direct patient care was provided.

PARTICIPANTS

National Hockey League athletes who underwent different orthopedic procedures were identified using public records. Three hundred thirty-seven athletes met inclusion criteria.

INDEPENDENT VARIABLES

Common orthopedic surgical procedures in NHL athletes.

MAIN OUTCOME MEASURES

Return-to-play and preoperative and postoperative performance measures were collected to calculate a position-specific performance score. Short-term and medium-term outcomes were defined as 1 and 2 to 3 seasons after surgery, respectively.

RESULTS

Three hundred seven athletes (92.6%) successfully returned to play. The number of games played during the first season after surgery compared with baseline was significantly decreased for hip arthroscopy (HA), noninstability shoulder arthroscopy (ie, shoulder arthroscopy procedure to address pathology other than shoulder instability), knee arthroscopy, and sports hernia repair (P = 0.002, 0.009, 0.03, and 0.01, respectively). The number of games played for seasons 2 and 3 after surgery was significantly decreased for both HA and noninstability shoulder arthroscopy (P = 0.01 and 0.001, respectively). Short-term postoperative performance scores were significantly decreased for HA, noninstability shoulder arthroscopy, and anterior cruciate ligament reconstruction (P = 0.00004, 0.02, and 0.02, respectively) while medium-term scores were significantly decreased for HA only (P = 0.009).

CONCLUSIONS

National Hockey League athletes return to play at a high rate after common orthopedic surgeries. However, certain procedures portend poorer performance scores and game participation than others. In particular, HA and noninstability shoulder arthroscopy have the greatest negative effect on NHL careers after surgery.

Mechanically superior matrices promote osteointegration and regeneration of anterior cruciate ligament tissue in rabbits

The gold standard treatment for anterior cruciate ligament (ACL) reconstruction is the use of tendon autografts and allografts. Limiting factors for this treatment include donor site morbidity, potential disease transmission, and variable graft quality. To address these limitations, we previously developed an off-the-shelf alternative, a poly(l-lactic) acid (PLLA) bioengineered ACL matrix, and demonstrated its feasibility to regenerate ACL tissue. This study aims to 1) accelerate the rate of regeneration using the bioengineered ACL matrix by supplementation with bone marrow aspirate concentrate (BMAC) and growth factors (BMP-2, FGF-2, and FGF-8) and 2) increase matrix strength retention. Histological evaluation showed robust tissue regeneration in all groups. The presence of cuboidal cells reminiscent of ACL fibroblasts and chondrocytes surrounded by an extracellular matrix rich in anionic macromolecules was up-regulated in the BMAC group. This was not observed in previous studies and is indicative of enhanced regeneration. Additionally, intraarticular treatment with FGF-2 and FGF-8 was found to suppress joint inflammation. To increase matrix strength retention, we incorporated nondegradable fibers, polyethylene terephthalate (PET), into the PLLA bioengineered ACL matrix to fabricate a "tiger graft." The tiger graft demonstrated the greatest peak loads among the experimental groups and the highest to date in a rabbit model. Moreover, the tiger graft showed superior osteointegration, making it an ideal bioengineered ACL matrix. The results of this study illustrate the beneficial effect bioactive factors and PET incorporation have on ACL regeneration and signal a promising step toward the clinical translation of a functional bioengineered ACL matrix.

Return to Play Following Isolated and Combined Anterior Cruciate Ligament Reconstruction: 25+ Years of Experience Treating National Football League Athletes

Background

The first case series to report on return to play (RTP) in National Football League (NFL) players after primary anterior cruciate ligament (ACL) reconstruction (ACLR) published an RTP rate of 63%. Other studies that have attempted to estimate RTP after ACLR in these elite athletes have been largely based on secondary sources. This study is the second to report the authors' own results in treating ACL injuries in NFL players spanning a study period of 25+ years.

Purpose

To report the senior authors' experience treating ACL injuries in NFL players as well as revisit the concept of RTP as it is currently used to measure successful surgical outcomes in professional athletes.

Study Design

Case series; Level of evidence, 4.

Methods

A total of 47 NFL players were treated at our institution for knee injuries that included a complete tear of the ACL; of these, 41 were primary ACLR and 6 were revision ACLR. Of the primary ACLRs, 6 were classified as ACL plus additional ligament and 3 were classified as multiligament. Return to game play (RTGP) was defined as returning to play in a regular-season game. Successful return to previous participation (RTPP) was defined as return to a level of participation equal to the level the player had reached before injury. Multivariate analysis was used to assess predictors of successful RTPP.

Results

Using the RTGP criteria proposed by prior authors, the RTGP after primary ACLR was 73%. Using our proposed RTPP criteria, 87.8% of players successfully returned to the same level of participation after primary ACLR. RTGP percentage for all NFL players after ACLR (including multiligament injuries) was 67.6%, and the overall RTPP for those patients was 87.8%. In multivariate analysis, age ≤25 years was predictive of successful RTPP. High draft picks and offensive players played more seasons after primary ACLR. ACL graft rupture occurred in 4.3% of this cohort. Contralateral ACL tear occurred in 8.5%.

Conclusion

Regardless of which definition is used to measure a successful outcome after ACLR surgery, the findings of this study suggest that successful return after primary ACLR in NFL athletes is higher than previously reported. While concomitant reconstruction of a single collateral ligament did not affect RTPP, revision ACLR or bicruciate plus collateral ligament reconstruction was associated with a lower RTPP rate. Age ≤25 years predicted successful RTPP. The risk of a future ACL tear of either knee after index reconstruction was approximately 13%.

Biomechanical Determinants of Knee Joint Loads Associated with Increased Anterior Cruciate Ligament Loading During Cutting: A Systematic Review and Technical Framework

Background

Cutting actions are associated with non-contact ACL injuries in multidirectional sports due to the propensity to generate large multiplanar knee joint loads (KJLs) that have the capacity to increase ACL loading and strain. Numerous studies have investigated the biomechanical determinants of KJLs in cutting tasks. The aim of this systematic review was to comprehensively review the literature regarding biomechanical determinants of KJLs during cutting, in order to develop a cutting technical framework alongside training recommendations for practitioners regarding KJL mitigation.

Methods

Databases (SPORTDiscus, Web of Science and PubMed) were systematically searched using a combination of the following terms: “Biomechanical determinants”, or “Knee abduction moment”, or “Technical determinants”, or “Knee loading”, or “Knee loads”, or “Mechanical determinants”, or “ACL strain”, or “Knee adduction moment”, or “Anterior tibial shear”, or “Knee internal rotation moment”, or “Knee valgus moment” AND “Change of direction”, or “Cutting manoeuvre”, or “Run and cut”, or “Run-and-cut”, or “Sidestepping”, or “Side-stepping”, or “Shuttle run”. Inclusion criteria were as follows: studies examining a cutting task < 110° with a preceding approach run that examined biomechanical determinants of KJLs using three-dimensional motion analysis.

Results

The search returned 6404 possibly eligible articles, and 6 identified through other sources. Following duplicate removal, 4421 titles and abstracts were screened, leaving 246 full texts to be screened for inclusion. Twenty-three full texts were deemed eligible for inclusion and identified numerous determinants of KJLs; 11 trunk, 11 hip, 7 knee, 3 multiplanar KJLs, 5 foot/ankle and 7 identifying ground reaction forces (GRFs) as determinants of KJLs.

Conclusion

Using the framework developed from the results, cutting KJLs can be mitigated through the following: reducing lateral foot-plant distances, thus lowering hip abduction and orientating the foot closer to neutral with a mid-foot or forefoot placement strategy; minimising knee valgus and hip internal rotation angles and motion at initial contact (IC) and weight acceptance (WA); avoiding and limiting lateral trunk flexion and attempt to maintain an upright trunk position or trunk lean into the intended direction; and finally, reducing GRF magnitude during WA, potentially by attenuation through increased knee flexion and emphasising a greater proportion of braking during the penultimate foot contact (PFC).