Incidence of Injury for Professional Soccer Players in the United States: A 6-Year Prospective Study of Major League Soccer.

Background: Despite an abundance of injury research focusing on European professional soccer athletes, there are limited injury data on professional soccer players in the United States. Purpose: To describe the epidemiology of injury across multiple years in Major League Soccer (MLS) players. Study Design: Descriptive epidemiology study. Methods: A web-based health management platform was used to prospectively collect injury data from all MLS teams between 2014 and 2019. An injury was defined as an incident that required medical attention and was recorded into the health management platform anytime over the course of the 2014-2019 seasons. Injuries and exposure data were recorded in training and match settings to calculate injury incidence. Results: A total of 9713 injuries were recorded between 2014 and 2019. A mean 1.1 injuries per year per player were identified, with midfielders sustaining the largest number of injuries. The most common injuries were hamstring strains (12.3%), ankle sprains (8.5%), and adductor strains (7.6%). The mean time missed per injury was 15.8 days, with 44.2% of injuries resulting in no days missed. Overall injury incidence was 8.7 per 1000 hours of exposure, declining over the course of the investigation, with a 4.1-times greater mean incidence during matches (14.0/1000 h) than training (3.4/1000 h). Conclusion: Between 2014 and 2019, the most commonly reported injuries in MLS players were hamstring strains, ankle sprains, and adductor strains. Injury incidence during matches was 4.1 times greater when compared with training, while overall injury incidence was found to decline during the course of the study period.

Increased Bite Distance From the Edge Lowers Risk of Pullout of Simple Sutures from Acellular Dermal Allograft.

PURPOSE: To investigate whether pullout strength in the acellular dermal allograft matrix (ADM) used for superior capsule reconstruction depends on the distance from the edge of the graft. METHODS: ADM used for superior capsule reconstruction was obtained and cut into 30 squares. Two sutures were placed through the center of each graft by using a loaded Keith needle and forming a simple stitch. The grafts were divided into 3 groups of 10 grafts with a distance of 5 mm, 10 mm or 15 mm from the closest edge of the graft, respectively. The grafts were then preloaded to 5 N and pulled to failure at a rate of 12 mm/s on an MTS 858 MiniBionix servohydraulic mechanical test frame. The load to failure was recorded as well as the stiffness of each graft. RESULTS: The mean load to failure was 34.5 N (SD 7.89) for the 5 mm grafts, 31.7 N (SD 5.99) for the 10 mm grafts, and 66.2 N (SD 18.4) for the 15 mm grafts. There was a significant difference (< 0.0001) between the large grafts (15 mm) and the 2 smaller grafts (10 mm, 5 mm). There was no significant difference in stiffness between the groups of graft (P 0.40). CONCLUSION: Placing the suture at least 15 mm from the edge of the graft increases the graft's ultimate yield strength to suture pullout. CLINICAL RELEVANCE: The depths of the suture in ADM could improve pullout strength for constructs of superior capsular reconstructions.

Injury Surveillance in Major League Soccer: A 4-Year Comparison of Injury on Natural Grass Versus Artificial Turf Field.

BACKGROUND: Artificial playing surfaces are becoming more common due to decreased cost of maintenance and increased field usability across different environmental conditions. The Fédération Internationale de Football Association (FIFA) has approved newer generation artificial turf for soccer competition at the elite level, but many elite-level athletes prefer to play on natural grass surfaces due to a perceived increase in injury rate, discomfort, and fatigability on artificial turf. HYPOTHESIS: Injury rates and rates of individually categorized types of injury experienced on artificial turf are noninferior to rates of injury on the standard comparator, natural grass, in elite-level Major League Soccer athletes. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: Over the course of 4 Major League Soccer seasons (2013-2016), athlete injury data were recorded electronically. Injury data recorded in matches between 2 Major League Soccer teams were then analyzed. Playing surface was known for each venue, and all artificial turf surfaces were rated as 2-star according to FIFA criteria. Incidence rate ratios (Artificial Turf ÷ Natural Grass) were calculated with a 95% CI (α = .05) for both overall injury incidence and individual injury subgroups. A noninferiority margin (δ) of 0.15 was used to determine noninferiority of injury incidence rates. RESULTS: A total of 2174 in-game injuries were recorded during the study period, with 1.54 injuries per game on artificial turf and 1.49 injuries per game on natural grass (incidence rate ratio, 1.033; 95% CI, 0.937-1.139). Within injury subgroups, overall ankle injury, Achilles injury, and ankle fracture were found to have a statistically higher incidence on artificial turf. Artificial turf was found to be noninferior to natural grass for overall foot injury and forefoot injury. No statistically significant differences were found in knee injuries between the 2 surfaces. CONCLUSION: The overall rate of injury on artificial turf was noninferior to that on natural grass. Within individual injury categories, a higher rate of ankle injury was found on artificial turf. No other injury subgroup demonstrated statistically significant differences between surfaces. CLINICAL RELEVANCE: FIFA 2-star rated artificial turf is a viable alternative to natural grass in elite-level soccer competition. Innovative research methods for comparing artificial turf versus natural grass may elucidate relative advantages with respect to player safety.

Head Injury in Soccer: From Science to the Field; summary of the head injury summit held in April 2017 in New York City, New York.

There has been an increased focus and awareness of head injury and sport-related concussion (SRC) across all sports from the medical and scientific communities, sports organisations, legislators, the media and the general population. Soccer, in particular, has been a focus of attention due to the popularity of the game, the frequency of SRC and the hypothesised effects of repetitive heading of the ball. Major League Soccer, US Soccer and the National Women's Soccer League jointly hosted a conference entitled, 'Head Injury in Soccer: From Science to the Field', on 21-22 April 2017 in New York City, New York. The mission of this conference was to identify, discuss and disseminate evidence-based science related to the findings and conclusions of the fifth International Conference on Concussion in Sport held by the Concussion in Sport Group and apply them to the sport of soccer. In addition, we reviewed information regarding the epidemiology and mechanism of head injuries in soccer at all levels of play, data regarding the biomechanics and effects of repetitive head impacts and other soccer-specific considerations. We discussed how to release the information raised during the summit to key stakeholders including athletes, parents, coaches and healthcare providers. We identified future areas for research and collaboration to enhance the health and safety of soccer (football) players.

The Effect of Playing Position on Injury Risk in Male Soccer Players: Systematic Review of the Literature and Risk Considerations for Each Playing Position.

Soccer (football) is a complex contact sport with a substantial risk of injury. As injury surveillance is the first step of the injury prevention paradigm, soccer epidemiology is well reported in the existing literature, but less is known about the actual role of player position on the general injury risk. The goal of this study is to present the existing evidence regarding the influence of player's position on general injury risk in male soccer. A systematic review of the Medline database was carried out. Only English written studies on male soccer and citing playing position as a possible determinant of injury risk were included. One hundred and two full texts were evaluated for eligibility, and 11 studies were selected for the qualitative synthesis. Of the 11 studies included in the systematic review, 5 didn't find any significant correlation with between player's position and general injury risk, while the remaining 6 studies found player's position to be correlated with injury risk, with mixed findings depending on each study. The most consistent finding was a tendency for goalkeepers (GKs) to sustain less injuries compared to outfield players. When considering only the studies reporting just the match injury risk, forwards seemed to be at higher risk, even if there wasn't a complete agreement. Few studies have evaluated a possible effect of playing position on general injury risk in male soccer. There is no agreement if weather or not different playing positions are associated to a higher injury risk. GKs seem to be at lower risk of injury when compared to outfield players.

Variables Associated with Chondral and Meniscal Injuries in Anterior Cruciate Ligament Surgery.

This article aims to evaluate factors associated with chondral and meniscal lesions in primary and revision anterior cruciate ligament (ACL) reconstructions. ACL reconstructions from 2001 to 2008 at a single institution were retrospectively analyzed. Logistic regression was used to estimate the association between chondral and meniscal injuries and age, gender, tear chronicity, additional ligamentous injuries, sport type, and participation level. Of the 3,040 ACL reconstructions analyzed, 90.4% were primary reconstructions and 9.6% were revisions. Meniscal injuries were significantly lower in the revision group (44.0 vs. 51.9%; p = 0.01), while chondral injuries were significantly higher in the revision group (39.9 vs. 24.0%; p < 0.0001). Inspection of the small subgroup (n = 85) receiving both primary and revision ACL surgery at our center indicated that meniscal injuries at revision were evenly split between menisci with and without previous repairs, whereas the vast majority of Grade III and IV chondral lesions were new. More patients presented for surgery later in the revision group than in the primary group (56.5 vs. 35.3%; p < 0.0001). Male gender, primary reconstruction, and short interval (less than 2 weeks) between injury and surgery were associated with increased likelihood of meniscus tear. Age (greater than 22 years) and long interval (greater than 6 weeks) between injury to surgery and higher sport activity level were associated with chondral lesions. Revision ACL reconstructions are associated with a higher proportion of chondral lesions and a lower proportion of meniscal tears. Early primary and revision ACL construction is recommended to reduce the probability of chondral lesions.

Return-to-Play Recommendations After Cervical, Thoracic, and Lumbar Spine Injuries: A Comprehensive Review.

CONTEXT: Currently, there is a national focus on establishing and disseminating standardized guidelines for return to play for athletes at all levels of competition. As more data become available, protocols and guidelines are being refined and implemented to assist physicians, coaches, trainers, players, and parents in making decisions about return to play. To date, no standardized criteria for returning to play exist for injuries to the spine. EVIDENCE ACQUISITION: Electronic databases including PubMed and MEDLINE and professional orthopaedic, neurosurgical, and spine organizational websites were reviewed between 1980 and 2015. STUDY DESIGN: Clinical review. LEVEL OF EVIDENCE: Level 4. RESULTS: Although clinical guidelines have been published for return to play after spine injury, they are almost exclusively derived from expert opinion and clinical experience rather than from well-designed studies. Furthermore, recommendations differ and vary depending on anatomic location, type of sport, and surgery performed. CONCLUSION: Despite a lack of consensus and specific recommendations, there is universal agreement that athletes should be pain free, completely neurologically intact, and have full strength and range of motion before returning to play after spinal injury.

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

BACKGROUND: Rupture of the anterior cruciate ligament (ACL) is a common and potentially career-threatening injury in the National Football League (NFL). The return to play (RTP) percentage and the factors affecting RTP after ACL reconstruction in NFL players are not well defined. PURPOSE: To determine the actual rate of return to professional football play in the NFL after ACL reconstruction surgery and to determine what factors can predict ability to RTP. We hypothesize that the RTP percentage in this unique patient population will differ from previously reported populations. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Forty-nine NFL athletes who had undergone primary ACL reconstruction at our institution were followed to determine their RTP percentages and factors predicting RTP. RESULTS: Sixty-three percent (31 of 49) of NFL athletes returned to NFL game play at an average of 10.8 months after surgery. Age at time of surgery, position, and the type and number of procedures were not significantly different between those who did and did not return to play. The average number of games before surgery was 51 for those who did return to play and 28 for those who did not (P = .039). The odds ratio favoring RTP was 5.5 (P = .016) for those players who had more than 4 years of NFL experience before surgery. The average NFL draft round was 3.4 for the group who returned to play and 6.4 for those who did not (P < .001). The odds ratio favoring RTP was 12.2 (P < .001) for those players drafted in the first 4 rounds of the NFL draft compared with those drafted after the fourth round. CONCLUSIONS: The RTP rates after ACL reconstruction in NFL football players are lower than previously perceived. More experienced and established athletes are more likely to return to competition at the same level after this procedure than those with less professional experience. Being selected in the first 4 rounds of the NFL draft was highly predictive of RTP.

Incomplete bicruciate knee injuries: Results of treatment with isolated anterior cruciate ligament reconstruction.

PURPOSE: To determine how the presence of a partial injury to the posterior cruciate ligament (PCL) in conjunction with an anterior cruciate ligament (ACL) tear affects the outcome of ACL reconstruction. TYPE OF STUDY: Case series. METHODS: Between 1990 and 1998, 18 patients with surgically documented complete ACL ruptures and partial PCL tears, referred to as "incomplete bicruciate knee injuries," were treated with arthroscopic ACL reconstruction and PCL observation. Fifteen patients (83%) were available for follow-up evaluation at a mean of 60 months postoperatively. Follow-up evaluation consisted of physical examination, standard radiographs, isokinetic muscle testing, KT instrumented laxity testing, stress radiographs for posterior and total anterior-posterior translation, and Lysholm, Tegner, and IKDC outcome scores. RESULTS: At follow-up, 11 patients had a negative Lachman and 4 had a 1+ Lachman (3 to 5 mm translation). Instrumented arthrometer tests performed at follow-up showed less than 3 mm of increased anterior translation versus the opposite knee on manual maximum testing at 30 degree in 11 patients, and 3 to 5 mm translation in the remaining 4 patients, with an average of 1.3 mm increased translation. Symptomatic posterior instability was present in only 1 patient who had sustained a repeat injury resulting in a complete PCL tear postoperatively. Final IKDC outcome scores were normal or near normal in 13 patients (87%) and abnormal in 2 (13%). The average Lysholm score was 93 at follow-up, and only 1 patient had a score lower than 80. CONCLUSIONS: Overall, the results of treatment of incomplete bicruciate knee injuries in this study compare favorably with the results of isolated ACL reconstruction reported in other series. We conclude that the clinical significance of an arthroscopically defined partial PCL tear in an ACL-deficient knee is minor, and that isolated ACL reconstruction in this setting appears to be effective treatment.

Analysis of arthroscopically assisted ankle arthrodesis.

PURPOSE: Evaluation of an arthroscopically assisted ankle arthrodesis technique for clinical and radiographic union, function, and patient satisfaction. TYPE OF STUDY: Retrospective analysis and review of the literature. METHODS: Twenty-one patients with a mean age of 52.7 years who underwent arthroscopic ankle arthrodesis were examined at an average follow-up time of 34 months. The mean duration of symptoms was 4.4 years. The most common diagnosis for patients who underwent arthrodesis was post-traumatic arthritis (19 of 21) with 1 patient having a diagnosis of avascular necrosis of the talus and the other patient having rheumatoid arthritis. All patients described severe mechanical pain as the most important reason for undergoing the procedure. RESULTS: Fusion occurred in 20 of 21 patients. The average time to clinical and radiographic union was 8.9 weeks. Nine patients were graded as excellent; no pain, limp, or occupational restriction, and a stable fusion. Eleven were graded as good; mild pain, occasional limp, or occupational restriction with a stable fusion. One was graded as poor; failed union and pain. The failure had extensive avascular necrosis involving approximately 50% of the talus as a preoperative diagnosis. CONCLUSIONS: The advantages of the arthroscopic technique include a high fusion rate, decreased time to fusion, and decreased cost. There are considerable advantages to the arthroscopic technique in appropriately selected patients with no or mild angular deformity and no avascular necrosis greater than 30% of the talus. There is a substantial reduction in time to fusion in the arthroscopic procedure compared with published reports on open procedures for ankle arthrodesis. While this procedure is not indicated in all instances, selected patients with disabling ankle arthrosis may be more appropriately treated with an arthroscopic arthrodesis than by open surgery.

Revision anterior cruciate ligament reconstruction surgery.

In 1995, it was reported that 60,000 to 75,000 anterior cruciate ligament (ACL) reconstructions were being performed annually in the United States. Successful long-term results are achieved in 75% to 95% of these patients, but 8% have unsatisfactory results due to recurrent instability and graft failure. With the increasing popularity of this procedure, ACL revision surgery has also become increasingly common. While the techniques described for ACL revision have been varied, the overall results in the literature do not compare favorably with primary ACL reconstruction. The proper execution of revision ACL reconstruction requires precise preoperative planning to assess the cause of initial failure and avoid repeating the same mistakes with revision reconstruction. Graft choice, hardware removal, revision notchplasty, tunnel placement, and method of fixation are key points for a successful result. The causes of ACL failure, the technical aspects of revision ACL surgery, and the reported results of revision ACL surgery are reviewed.

Thermal capsulorrhaphy in the treatment of multidirectional instability of the shoulder.

The treatment of symptomatic multidirectional instability (MDI) of the shoulder has proven a challenge to orthopaedic surgeons. Patients who refuse activity modification often fail nonsurgical management, and traditional surgical approaches may trade the dysfunction of instability for that of decreased motion and possible future arthrosis. Recently, several methods of arthroscopic thermal capsulorrhaphy have gained popularity. Studies have shown that capsular shrinkage occurs due to the denaturation of type I collagen with maintenance of heat-stable intermolecular cross-links. Thermally treated tissues undergo a predictable healing response. The primary advantages of this procedure are the decreased surgical morbidity and ease of procedure compared with open capsular shift. Additionally, it may provide improved stability and decreased pain while maintaining range of motion. When radiofrequency treatment provides inadequate visualized capsular contracture, arthroscopic rotator interval closure can improve stability without resorting to an open procedure. While initial results in certain clinical series are promising, the long-term efficacy remains to be seen.