American Journal of Sports Medicine

BACKGROUND: The benefits of platelet-rich plasma (PRP) are believed to be in part dependent on growth factor release after platelet activation. Platelet activation is complex and involves multiple mechanisms. One important mechanism is driven by cyclooxygenase 1 (COX-1)-mediated conversion of arachidonic acid (AA) to precursor prostaglandins that then mediate proinflammatory responses that trigger growth factor release. Acetylsalicylic acid (ASA; also known as aspirin) is known to irreversibly inhibit COX-1, thereby blocking AA-mediated signaling; however, it is unclear whether ASA use alters growth factor release from freshly isolated PRP...

BACKGROUND: Injuries remain a significant problem for professional baseball players. There is little information regarding the incidence and outcomes of shoulder surgical procedures among these athletes. PURPOSE/HYPOTHESIS: To report the incidence, pathology, procedure type, demographics, and return-to-sport (RTS) rate of shoulder surgery among Major League Baseball (MLB) players. Most shoulder procedures would be performed on pitchers with a history of injury; the labrum would be the most commonly involved; and that the RTS rate would be >50%...

BACKGROUND: The length of most patient-reported outcome measures creates significant response burden, which hampers follow-up rates. The Patient Acceptable Symptom State (PASS) is a single-item, patient-reported outcome measure that asks patients to consider all aspects of life to determine whether the state of their joint is satisfactory; this measure may be viable for tracking outcomes on a large scale. HYPOTHESIS: The PASS question would identify clinically successful anterior cruciate ligament reconstruction (ACLR) at 1-year follow-up with high sensitivity and moderate specificity...

BACKGROUND: Isolated ulnar nerve decompression/transposition is an uncommon surgical procedure among professional baseball players. PURPOSE/HYPOTHESIS: To determine performance and rate of return to sport (RTS) among professional baseball players after isolated ulnar nerve decompression/transposition, including those who required decompression/transposition after ulnar collateral ligament reconstruction (UCLR), and to compare outcomes between cases and matched controls...

BACKGROUND: An isolated arthroscopic Bankart repair carries a high mid- and long-term risk of recurring instability. Preoperative patient selection based on the Instability Severity Index Score should improve outcomes. PURPOSE: To report the overall long-term recurrence rate for isolated Bankart repair, investigate the predictive factors for recurrence, analyze time to recurrence, and determine a quantitative cutoff point for recurrence in terms of Instability Severity Index Score...

BACKGROUND: Young age and contact sports have been postulated as risk factors for anterior shoulder instability. Management after shoulder instability is controversial, with studies suggesting that nonoperative management increases the risk of recurrence. Several studies examined return to play after an in-season instability episode, and few followed these patients to determine if they were able to successfully compete in a subsequent season. No study has evaluated this question in a high school athlete population...

BACKGROUND: Hip microinstability is an increasingly recognized source of hip pain and disability. Although the clinical entity has been well described, the pathomechanics of this disease remain poorly understood. PURPOSE/HYPOTHESIS: The purpose of this study was to determine the role of capsular laxity in atraumatic hip microinstability. Our hypothesis was that cyclic stretching of the anterior hip capsule would result in increased hip range of motion and femoral head displacement...

BACKGROUND: Return to sport (RTS) remains an important challenge and measure of success for athletes undergoing arthroscopic rotator cuff repair (RCR). PURPOSE: To determine the rate of RTS after RCR and to analyze predictive factors associated with a lower rate of return. STUDY DESIGN: Systematic review and meta-analysis. METHODS: A systematic review of the literature was performed following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines...

BACKGROUND: Platelet-rich plasma (PRP) is an autologous orthobiologic treatment option for musculoskeletal conditions with favorable results in a limited number of high-quality clinical trials. Because different blood-processing methods result in PRP with varying cellular and growth factor content, it is critical that clinicians understand the content of the specific PRP being used in clinical practice. One adjustable system, the Angel System, has few independent laboratory reports on the specific composition of its PRP...

BACKGROUND: In vivo amniotic fluid is known to contain a population of mesenchymal stem cells (MSCs) and growth factors and has been shown to assist in healing when used as an adjunct in procedures across multiple medical specialties. It is unclear whether amniotic fluid products (AFPs) contain MSCs and, if so, whether the cells remain viable after processing. PURPOSE: To determine whether MSCs, growth factors, and hyaluronan are present in commercially available AFPs...

BACKGROUND: A previously published trial showed that patients with chronic gluteal tendinopathy achieved greater clinical improvement at 12 weeks when treated with a single platelet-rich plasma (PRP) injection than those treated with a single corticosteroid injection (CSI). PURPOSE: This follow-up study was conducted to determine whether there would be a sustained long-term difference in the modified Harris Hip Score (mHHS) at 2 years for a leucocyte-rich PRP (LR-PRP) injection in the treatment of chronic gluteal tendinopathy...

BACKGROUND: There is no agreement on the best treatment for displaced midshaft clavicle fractures (MCFs), which are currently addressed by nonoperative or surgical approaches. PURPOSE: The aim of this meta-analysis was to compare fracture healing and functional outcome after surgical versus nonsurgical treatment of MCFs, to help specialists in deciding between these different strategies by providing a synthesis of the best literature evidence. STUDY DESIGN: Meta-analysis...

BACKGROUND: Wearable sensor systems have the potential to quantify head kinematic responses of head impacts in soccer. However, on-field use of sensors (eg, accelerometers) remains challenging, owing to poor coupling to the head and difficulties discriminating low-severity direct head impacts from inertial loading of the head from human movements, such as jumping and landing. PURPOSE: To test the validity of an in-ear sensor for quantifying head impacts in youth soccer...

BACKGROUND: Although data exist on injuries in youth football leagues, there are limited recent data on injury incidence in middle school football. Updated injury incidence estimates can help drive the development of injury prevention strategies. PURPOSE: Describe the epidemiology of injuries in middle school football during school years 2015-2016 to 2017-2018. STUDY DESIGN: Descriptive epidemiology study. METHODS: Data originated from 9 public middle schools in Virginia during school years 2015-2016 to 2017-2018...

BACKGROUND: Meniscal repair is desirable over resection to prevent postmeniscectomy arthritis, especially among young and active patients. However, long-term data are currently lacking following isolated meniscal repair, particularly in the pediatric population. PURPOSE/HYPOTHESIS: To report long-term follow-up of isolated meniscal tears treated by meniscal repair in a pediatric and adolescent population and to compare those results with previous midterm follow-up data reported...

BACKGROUND: Some athletes demonstrate excellent dynamic stability after anterior cruciate ligament (ACL) rupture and return to sport without ACL reconstruction (ACLR) (copers). Others demonstrate persistent instability despite rehabilitation (noncopers) and require surgical stabilization. Testing to determine coper classification can identify potential copers early after rupture. It is unclear how coper classification changes after a brief intervention and how early classification relates to long-term outcomes...

BACKGROUND: Comprehensive studies evaluating quadriceps tendon (QT) autograft for anterior cruciate ligament (ACL) reconstruction are lacking. The optimal choice of graft between bone-patellar tendon-bone (BPTB), hamstring tendon (HT), and QT is still debatable. HYPOTHESIS: The current literature supports the use of QT as a strong autograft with good outcomes when used in ACL reconstruction. STUDY DESIGN: Meta-analysis; Level of evidence, 2...

BACKGROUND: The success of hip arthroscopy has led to increased application in younger populations. However, hip arthroscopy remains a challenging procedure, and its safety and efficacy in the adolescent population have been controversial. Most existing literature on outcomes in such patients contains only short-term follow-up, and a paucity of evidence is available regarding long-term outcomes in adolescents. PURPOSE: To report on clinical outcomes at a minimum 5-year follow-up in patients younger than 18 years who underwent arthroscopic treatment of labral tears...

BACKGROUND: Quadrupled semitendinosus (ST) grafts for anterior cruciate ligament (ACL) reconstruction have advantages of greater graft diameter and gracilis (G) preservation compared with doubled ST-G grafts. However, a paucity of biomechanical data are available regarding different preparation techniques for these constructs. PURPOSE: To biomechanically analyze 3 alternative tendon constructs fixed with adjustable suspensory fixation devices on the femur and tibia compared with a matched 4-strand construct fixed with a tibial screw and femoral fixed loop device...

BACKGROUND: Lower psychological readiness to return to sport has been reported for younger patients (≤20 years) who go on to a second anterior cruciate ligament (ACL) injury. However, changes in psychological readiness and specific psychological responses associated with second injury have not been identified. PURPOSE/HYPOTHESIS: To identify changes in psychological readiness over time associated with a second ACL injury. It was hypothesized that younger patients who suffered a second injury would have smaller changes in psychological readiness to return to sport when compared with those who did not have a second injury...