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AbstractThe meniscal ossicle is observed in clinical practice, yet there currently is limited information on its potential clinical significance. The purpose of this study was to assess the clinical presentation, imaging findings, and clinical treatment and outcomes of a series of patients identified as having a meniscal ossicle. An institutional database was reviewed to identify knees with a meniscal ossicle. Clinical presentation, magnetic resonance imaging (MRI), treatment, and outcomes were analyzed. Radiographs were graded using Kellgren–Lawrence (KL) scores. MRIs were reviewed for the presence and location of meniscal ossicles and additional knee pathology. Knee arthroplasty rates were recorded with the remaining patients contacted to obtain final International Knee Documentation Committee (IKDC) and Tegner's scores. Failure was defined as conversion to arthroplasty or failing IKDC score (< 75.4). Forty-five meniscal ossicles in 45 patients (26 males and 19 females) with a mean age of 51 years (standard deviation [SD] = 19.0) were included. Pain was the most common presenting symptom (89%). Forty-two patients (93%) had an associated meniscus root tear on MRI. Eighteen percent of patients that did not have an ossicle on initial imaging subsequently developed an ossicle. Mean KL grades progressed significantly from baseline of 1.84 (SD = 1.0) to 2.55 (SD = 0.93 p < 0.01) on final follow-up. Thirty-nine percent of baseline radiographs showed KL grades of less than 2 compared with only 15% of follow-up radiographs (p = 0.04). Mean IKDC score obtained for patients ≤ 60 at an average follow-up of 3.1 years (SD = 3.2) was 65.2 (SD = 19.0). Eight out of 45 patients (18%) had progressed to total knee arthroplasty (TKA) by latest available follow-up. Sixty-two percent of patients met failure criteria at latest available follow-up. The meniscal ossicle is most commonly found in the posterior horn or root of the medial meniscus and is highly suggestive to be sequelae of a posterior root tear. Therefore, the presence of a meniscal ossicle should alert the orthopaedic surgeon to the high likelihood of the patient having a meniscus root tear. These patients have shown to have poor clinical outcomes and worsening arthritis.

Purpose To report the rate of radiographic union, patient‐reported outcomes, complications, and reoperations after internal fixation of unstable osteochondritis dissecans (OCD) in the skeletally mature knee. Methods A literature search was conducted according to Preferred Reporting Items for Systematic Reviews and Meta‐Analysis guidelines. Patients were included if they were skeletally mature and underwent internal fixation of an unstable OCD lesion of the knee. Risk of bias assessment was performed using the Methodological Index for Non‐randomized Studies scoring system. Surgical technique, rate of union, patient‐reported outcomes, complications, and reoperations were collected. Results Thirteen studies resulted in 148 patients (150 knees) for inclusion. Patient age ranged from 14 to 45 years. Numerous fixation procedures were used, including biodegradable devices (rods, pins, nails, and screws), metal screws, Kirschner wire, and autologous bone sticks. Overall, reported outcome measures were heterogeneous in nature. The rate of radiographic healing ranged from 67% to 100% across 6 studies. Improved subjective results and Hughston criteria on final follow‐up ranged from 83% to 100% across 4 studies each. Mean postoperative Lysholm scores ranged from 42 to 98 in studies that reported them. Both complication and reoperation rates ranged from 0% to 44%. The most commonly performed reoperations were loose body excision and cartilage resurfacing procedures. Conclusions A variety of surgical techniques are available for treatment of unstable OCD lesions in the skeletally mature knee. In this systematic review, internal fixation of the native fragment showed acceptable rates of radiographic union and improved patient‐reported outcomes relative to other techniques. Level of Evidence Level IV, systematic review of level III‐IV studies.

Background: Hamstring strains are the most common injury for professional baseball players and can result in significant time on the disabled list. To date, no study has reported the current trends in hamstring strains in professional baseball. Hypothesis: Professional baseball players would have an increased incidence of hamstring strains from 2011 through 2016. Study Design: Descriptive epidemiology study. Methods: Injury data were prospectively collected from 2011 through 2016 for every Major League Baseball (MLB) and Minor League Baseball (MiLB) team and was recorded in the MLB Health and Injury Tracking System. Data collected for this study included date of injury, activity during injury, time lost, primary injury or reinjury status, and imaging findings as well as player demographic information related to level of play, age, and position for all hamstring injury events. Injury rates were reported as hamstring injuries per number of games. Results: From 2011 to 2016, there were 2633 hamstring strains in professional baseball players. The rate of hamstring strains increased in MLB from a low of 1 injury every 39 games in 2011 to a high of 1 injury every 30 games in 2016. In MiLB, there were 2192 hamstring strains, with 1 injury every 35 games in 2011 compared with 1 injury every 30 games in 2016. The majority of injuries occurred in the infielder positions (37.5%) and resulted from base running (>50%), most commonly from home to first base. The most common hamstring injury was a grade 2 injury to the distal biceps femoris. The mean time missed after a hamstring injury was 14.5 days. Grade 3 and grade 2 hamstring strains resulted in significantly more days missed compared with grade 1 injuries ( P = .005 and P = .002, respectively). The rate of recurrent hamstring injuries was 16.3% for MLB and 14.2% for MiLB. Recurrent hamstring injuries resulted in more time lost than primary injuries (mean, 16.4 vs 14.5 days, respectively; P = .02). A total of 42 injuries were treated with platelet-rich plasma, and 19 were treated with surgery. The number of injuries treated with platelet-rich plasma increased in successive years. Conclusion: The rate of hamstring strains in professional baseball players has increased over the past 6 years and has resulted in a significant loss of playing time. Study results indicated that these injuries are affected by injury characteristics, position played, running to first base, seasonal timing, and history of hamstring injuries.

Objectives: Traditional pitching statistics (ERA, WHIP, etc) have been used as surrogates for pitcher performance without being validated. Even amongst healthy pitchers, the normal variability of these parameters has not yet been established. The purpose of this study was to determine the normal variability of basic and advanced pitching statistics in non-injured Major League Baseball (MLB) pitchers. It is our hope that this work will serve as the foundation for the identification and implementation of validated, pitcher dependent statistical measures that can be used to assess return to play performance following injury. Methods: Publicly available data from MLB Statcast and Pitch/Fx databases was used to analyze all non-injured MLB pitchers during 2015 and 2016 seasons who pitcher greater than 100 innings each season without injury. Traditional and advanced baseball pitching statistics were analyzed. The variability of each parameter was assessed by computing coefficient of variation (CV) between individual pitchers and across all pitchers. A CV below 10 is typically indicative of a relatively constant parameter, and parameters with a CV > 10 are generally considered inconsistent and unreliable. Results: A total of 118 pitchers met all inclusion criteria. For each of these healthy pitchers, 38 basic/traditional parameters and 17 advanced parameters were analyzed. Of the traditional pitcher statistics, only 1 (3%) demonstrated a CV value < 10 (average fastball velocity [FBv]; CV 1.5) (Figure 1). In advanced statistics, 9 of 17 (53%) variables demonstrated acceptable consistency as evidenced by a CV value < 10 (Figure 2). Release position from plate (release_pos_y) along with velocity from the plate (vy0) where the two most constant advanced parameters. When separated by pitch type, these two parameters were the most constant (lowest CV) in every pitch type. Conclusion: The validity and variability of baseball statistics as surrogate markers for performance after injury/surgery have not yet been evaluated. It is critical that baseball statistics undergo proper vetting prior to being used to assess recovery. This study reveals average fastball velocity and release position from the plate to be the least variable basic and advanced baseball statistics in MLB pitchers. In total, only 10 of the 55 statistics analyzed demonstrated acceptable consistency and reliability. This study can be further used to determine the minimum time that each of these variables needs to be followed to ensure an appropriate sample size is obtained to detect significant differences in pre- and post- injury performance. [Figure: see text][Figure: see text]

Objectives: The variability of throwing metrics, particularly elbow torque and ball velocity, during structured long-toss programs is yet to be fully elucidated. The primary aims of this study were to assess various throwing metrics through a structured long-toss program using wearable technology and to quantify the intra and inter thrower variability of these metrics at each stage of throwing. Methods: This was a descriptive laboratory study in which 60 high school and collegiate pitchers participated in a predetermined, structured, progressive long-toss program. All players wore a motusBASEBALL sleeve (Motus Global, Inc.; Rockville Centre, NY), which measured arm slot, arm velocity, shoulder rotation, and elbow varus torque. Radar guns were used to measure ball velocity. These metrics were compared within and between all pitchers at each of the following throwing distances: 90 ft, 120 ft, 150 ft, 180 ft, and maximum effort mound pitching. Intra- and inter- thrower reliabilities were calculated for each throwing metric at every stage of the program. Excellent intra-thrower reliability was defined by an Intra-class coefficient (ICC) >0.750. Acceptable inter-thrower reliability was defined by a Coefficient of Variation (CV) <5%. Results: Ball velocity significantly changed at each progressive throwing distance, but this did not consistently correlate with an increase in elbow torque. Pitching from the mound did not place more torque on the elbow than throwing from 120 ft and beyond. Intra-thrower reliability was excellent throughout the progressive long-toss program for each throwing metric. Ninety-one percent of throwers had acceptable inter-thrower reliability for ball velocity, whereas only 79% of throwers had acceptable inter-thrower reliability for elbow torque. Conclusion: Based on trends in elbow torque, it may be practical to incorporate pitching from the mound earlier in the program (once a player is comfortable throwing from 120 ft). Ball velocity and elbow torque do not necessarily correlate with one another, so a degree of caution should be exercised when using radar guns to estimate elbow torque. Given the variability in elbow torque between throwers, some athletes would likely benefit from an individualized throwing program.

Objectives: Progressive throwing programs are a mainstay of rehabilitating the throwing athlete after injury or surgery. Athletes are commonly asked to throw at reduced levels of effort (i.e. “50% effort”, ”75%,” etc) to minimize stress to healing tissues. However, it is unknown whether players’ perceived exertion matches actual exertion. The purpose of this study was to determine whether decreased effort correlates with decreased throwing metrics, whether metrics decrease to a predictable degree, and to quantify variability of these metrics within a given athlete when attempting to throw at sub-maximal effort. Methods: Sixty healthy, high school and collegiate baseball pitchers participated in a structured throwing program. After warming up, each pitcher was asked to throw five, max effort long toss throws at a distance of 120 feet. Afterwards, they were asked to give 5 throws at both 75% effort and 50% effort from the same distance. A motusBASEBALL sleeve (Motus Global, Inc.; Massapequa, NY) was worn by all players, which measured arm slot, velocity, shoulder rotation, and elbow varus torque (Nm). Ball velocity was measured in miles per hour (MPH) using a radar gun. The observed changes in throwing metrics were compared to one another across each of the throwing scenarios using a general estimating equation to control for multiple comparisons. They were also compared to the expected change to see if a decrease from 100% effort to 75%, and then to 50% resulted in proportional decreases in elbow torque and ball velocity. Intra-thrower variability was determined for each throwing metric at each degree of effort, and these results are reported using intra-class correlation coefficients (ICC) where an ICC > 0.75 was considered to represent excellent agreement. Results: Mean elbow torque decreased as players decreased their perceived effort from 100% (72.7 Nm) to 75% (67.3 Nm) to 50% (62.s Nm) (p<0.001). Mean ball velocity also decreased as they progressed from 100% effort (77.8 MPH) to 75% effort (66.5) to 50% effort (60.3 MPH) throws (p<0.001). However, these observed decreases in torque and velocity were much smaller in magnitude than the decreases in perceived effort. During the 75% effort throws, torque and velocity were not reduced to 75% of max. Instead, elbow torque was only reduced to 93.3% of max, and velocity dropped to 86.1% of max. Similarly, for the 50% effort throws, torque remained 86.5% of max effort torque, while velocity remained 78.1% of max. Accordingly, for every 25% decrease in perceived effort, torque only decreased 7%, and velocity only decreased 11%. These observed differences were all significantly different than the expected differences (p<0.001 for all). Intra-thrower reliability was considered excellent for all metrics within each throwing scenario: max effort, 75% effort, and 50% effort (ICC>0.75 for all). Conclusion: Measured effort was significantly greater than perceived effort during this standardized throwing program for all metrics tested. This is especially true for ball velocity and varus elbow torque. Ultimately, when players throw at what they perceive to be “reduced effort,” their actual throwing metrics do not decrease at the same rate as their perceived exertion. This has significant implications for throwers during the rehabilitation process as their elbows are likely experiencing more stress than desired. Clinicians and coaches must be aware and may want to consider transitioning to more objective measures of effort during rehabilition.

Objectives: The incidence of shoulder and elbow overuse injury continues to rise in youth baseball players. Several throwing programs designed to reduce stress on the elbow have been described, but most are not evidence-based. The aim of this study was to compare the kinetics and kinematics between mound and flat-ground pitching at two different distances with the goal of developing evidenced-based injury prevention and recovery guidelines for youth throwers. Methods: Fifteen healthy, high school varsity-level baseball pitchers (mean age 16.7 ± 0.7 yrs; height 182.2 ± 6.2 cm; weight 76.0 ± 9.4 kg;) participated in the study. Players were fitted with a motusBASEBALLTM sensor and sleeve (Motus Global, Rockville Centre, NY), which has been shown to have good reliability and correlation with in-laboratory measures. Each pitcher was asked to pitch 5 fastballs to a catcher under each of the 4 conditions: mound at 60.5 ft (regulation distance), flat ground at 60.5 ft, mound at 50.5 ft, and flat ground at 50.5 ft. For each pitch, the sensor recorded arm speed, arm slot, shoulder rotation, and elbow varus torque. Ball velocity was tracked with a radar gun (Stalker Radar, Richardson, TX). Linear mixed-effects models were used to account for both within and between-subject variability. A multivariable model was used to evaluate the association of mound pitching (vs flat ground), distance (50.5 vs 60.5 ft), and their interaction on each of the following outcomes: arm speed, arm slot, shoulder rotation, elbow varus torque, and ball velocity. Results: There were no statistically significant effects of mound vs flat ground or distance variation on both arm speed or shoulder rotation. Arm slot was significantly higher on pitches from the mound at 60.5 ft [+4.58 (95% CI: 1.26, 7.90), p=0.007]. Elbow varus torque was significantly lower on throws from the mound [-1.88 (95% CI: -3.56, -0.20), p=0.03] and from a longer distance [-2.21 (95% CI: -3.89, -0.53), p=0.01]. Pitches thrown from the mound were significantly faster compared to flat ground at both distances, with throws at 60.5 ft of greater velocity than at 50.5 ft [+1.03 (95% CI: 0.66, 1.40), p<0.001]. Please see the Table for full results. Conclusion: The findings suggest that throwing from the mound may not be higher risk compared to flat ground, contrary to long-standing notions. The lower elbow varus torque and higher arm slot, which has previously been shown to be associated with reduced stress, from throwing from the mound may even indicate a protective effect. Compared to 50.5 ft, there was lower elbow varus torque and faster ball velocity at the longer distance, indicating that elbow stress and ball velocity may not correlate perfectly, and radar guns may not be an appropriate surrogate measure of elbow varus torque. A better understanding of the kinetic and kinematic implications of various throwing programs will allow for designing programs that are based on objective data to achieve the goal of preventing injuries in young baseball players. [Table: see text]

Objectives: Ulnar collateral ligament (UCL) reconstruction of the elbow is a commonly performed surgery on professional baseball pitchers. Recent reports have suggested that revision rates are on the rise and may be higher than previously thought. The purpose of this study is to provide a comprehensive report on current trends, surgical techniques, and outcomes of revision UCL reconstructions performed on professional baseball pitchers between 2010 and 2016. Methods: The Major League Baseball (MLB) Health and Injury Tracking System (HITS) was used to compile records of all revision UCL reconstructions performed on professional baseball pitchers between 2010 and 2016. Player data and outcomes were obtained from HITS while surgical details were obtained from operative reports. Descriptive statistical analysis was performed on epidemiologic data. Outcomes (return to play rates, return to play times, subsequent injuries, and subsequent surgeries) were compared across the most common surgical techniques (Docking vs. Modified Jobe) and graft sources (palmaris longus autograft vs. hamstring autograft). Results: A total of 69 professional baseball pitchers underwent revision UCL reconstruction from 2010 to 2016 at an average of 1,424 days (47 months) after their primary surgery. There was a trend toward increasing numbers of revision surgeries over time (R2=0.441; p=0.104). The most commonly used tunnel configuration was the Modified Jobe technique (n=41, 59.4%) and the most common graft utilized was hamstring autograft (n=34, 49.3%). 76.6% of pitchers were able to return to play (RTP) and 55.3% were able to return to the same level of play. Mean time to RTP in players with a palmaris longus autograft was 436 days versus 540 days for hamstring autograft (p=0.108) and the mean time to RTP in players was 423 days for the Docking technique versus 519 days for the Modified Jobe technique (p=0.296). Similar rates of subsequent injuries and surgeries were noted between the two revision techniques and two most commonly used graft constructs. Conclusion: This report detailing revision UCL reconstruction amongst professional baseball pitchers showed a trend towards increasing numbers of revisions being performed, a finding consistent with other recent studies. The overall return to play percentage was higher than previously reported (76.6%); however, significantly fewer (55.3%) players returned to the same level of play. This work also demonstrated decreased return to play times (n=484 days, SD: 117.3) compared to other investigations. The Modified Jobe was the most commonly used surgical technique and the two most commonly used graft constructs were hamstring autograft and palmaris longus autograft. Although this analysis did not reveal any statistically significant comparative differences between surgical techniques or graft constructs, future studies involving head-to-head comparisons of these surgical variables, specific to revision UCL reconstruction, may be helpful in improving player outcomes and career performance.

Objectives: Little is known about the natural history and long-term outcome of a surgically treated symptomatic lateral discoid meniscus. The goals of this study were to describe the rate and factors associated with recurrent lateral meniscus tears and progression to symptomatic lateral compartment osteoarthritis (OA) in patients surgically treated for a symptomatic lateral discoid meniscus. Patients with surgically treated lateral discoid meniscus have a high incidence of meniscus re-tear and progression to lateral compartment OA. Methods: A large, geographic database was reviewed to identify and confirm patients presenting with symptomatic lateral discoid meniscus between 1998 and 2015. Charts were reviewed to document treatment and outcomes at a minimum clinical follow-up of two years. Results: 70 discoid meniscus patients (30 F, 40 M) with a mean age of 27 years (Range: 2.0-66.0) were followed for an average of 5.8 years (Range 2.0-23.7). Sixty patients underwent surgical management: 49 (82%) patients underwent partial lateral meniscectomy and 11 (18%) underwent meniscus repair (including saucerization). Tear-free survival following surgery was 93% at 2 years, 69% at 5 years, and 40% at 8 years. Overall progression to symptomatic lateral compartment OA in the surgical group was 10% at 2 years, 23% at 5 years, and 48% at 8 years. Of those patients who developed lateral compartment OA, 55% (11/20) had a Kellgren-Lawrence score 2 or greater at last radiographic follow-up. Young age and open growth plates were associated with increased incidence of postoperative re-tear (HR: 0.96, CI: 0.93-0.99, p = 0.01). Increased age at diagnosis and BMI ≥ 30 were associated with increased risk of progression to lateral compartment OA on final radiographs. Conclusion: Patients with a surgically treated lateral discoid meniscus tear had a high rate of recurrent meniscus tear at long-term follow-up (60% at 8 years) that was associated with young age. Approximately 48% of surgically treated patients developed symptomatic lateral compartment OA at eight years from initial presentation. The risk of progression to OA increased with older age at diagnosis and BMI ≥ 30.

Background: Professional baseball players are at risk of acute and chronic injuries to their upper extremities. Methods: Major League Baseball’s Health and Injury Tracking System, a prospective injury surveillance system, was used to identify and characterize all hand and wrist injuries sustained by all Major League Baseball (MLB) and Minor League Baseball (MiLB) players during the pre-, regular, and postseason throughout 2011-2016. Injuries were included if they resulted in at least 1 day out of play and were sustained during standard baseball activities. Days missed were defined as the time between injury and the first time in which a player was cleared to return to play. Results: During the study period, there were 4478 hand and 1748 wrist injuries throughout MLB and MiLB, which resulted in a total of 105 246 days out of play. This was equivalent to the length of 575 individual MLB player seasons, and the mean days missed per injury was 17 days. Most injuries were traumatic in nature, with 43% (n = 2672) of players injured after being hit by a baseball that mainly occurred during batting (n = 2521; 40%). Injuries that most frequently required surgical intervention were hook of hamate fractures (72%) and scaphoid fractures (60%). Conclusions: Understanding the epidemiology and impact of hand and wrist injuries in MLB and MiLB players may lead to improved management of these injuries and reduce time away from play. Most importantly, preventive measures and/or enhanced protective gear may be developed to minimize these types of injuries in MLB and MiLB.