Return To Play Time Research Articles

Epidemiology, Treatment, and Performance-Based Outcomes in American Professional Baseball Players With Symptomatic Spondylolysis and Isthmic Spondylolisthesis

Background: Repetitive lumbar hyperextension and rotation during athletic activity affect the structural integrity of the lumbar spine. While many sports have been associated with an increased risk of developing a pars defect, few previous studies have systematically investigated spondylolysis and spondylolisthesis in professional baseball players. Purpose: To characterize the epidemiology and treatment of symptomatic lumbar spondylolysis and isthmic spondylolisthesis in American professional baseball players. We also sought to report the return-to-play (RTP) and performance-based outcomes associated with the diagnosis of a pars defect in this elite athlete population. Study Design: Descriptive epidemiology study. Methods: A retrospective cohort study was conducted among all Major and Minor League Baseball (MLB and MiLB, respectively) players who had low back pain and underwent lumbar spine imaging between 2011 and 2016. Players with radiological evidence of a pars defect (with or without listhesis) were included. Analyses were conducted to assess the association between player-specific characteristics and RTP time. Baseball performance metrics were also compared before and after the injury episode to determine whether there was an association between the diagnosis of a pars defect and diminished player performance. Results: During the study period of 6 MLB seasons, 272 professional baseball players had low back pain and underwent lumbar spine imaging. Overall, 75 of these athletes (27.6%) received a diagnosis of pars defect. All affected athletes except one (98.7%) successfully returned to professional baseball, with a median RTP time of 51 days. Players with spondylolisthesis returned to play faster than those with spondylolysis, MLB athletes returned faster than MiLB athletes, and position players returned faster than pitchers. Athletes with a diagnosed pars defect did not show a significant decline in performance after returning to competition after their injury episode. Conclusion: Lumbar pars defects were a common cause of low back pain in American professional baseball players. The vast majority of affected athletes were able to return to competition without demonstrating a significant decline in baseball performance.

Modified Jobe Versus Docking Technique for Elbow Ulnar Collateral Ligament Reconstruction: A Systematic Review and Meta-analysis of Clinical Outcomes

Background: The modified Jobe and docking techniques are the most common techniques used for elbow ulnar collateral ligament (UCL) reconstruction. Previous systematic reviews have suggested that the docking technique results in superior outcomes as compared with the Jobe (figure-of-8) technique. However, these included results from earlier studies in which the flexor-pronator mass (FPM) was detached and an obligatory submuscular ulnar nerve transposition was performed. Purpose/Hypothesis: The purpose was to compare the outcomes and return-to-play (RTP) time between the docking and figure-of-8 techniques for UCL reconstruction. We hypothesized that there would be no significant difference in the proportion of excellent outcomes between techniques when the FPM was preserved and no obligatory submuscular ulnar nerve transposition was performed. We also hypothesized that there would be no significant difference in RTP time between techniques. Study Design: Systematic review and meta-analysis. Methods: This study was performed in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. In the primary analysis, techniques were compared in random effects models by using the restricted maximum likelihood method, with weighted effect sizes calculated as the Freeman-Tukey double-arcsine transformed proportion of excellent outcomes for variance stabilization and with summary effects estimated from the inverse double-arcsine transformation per the harmonic mean of the sample sizes. Mean RTP times for techniques were compared in a separate model. Results: There were 21 eligible articles identified, with results for 1842 UCL reconstructions (n = 320, docking; n = 1466, figure-of-8). Without controlling for the effects of flexor-pronator detachment and submuscular ulnar nerve transposition, a significantly larger proportion of excellent outcomes was observed with docking reconstruction (86.58%; 95% CI, 80.42%-91.85%) than with figure-of-8 reconstruction (76.76%; 95% CI, 69.65%-83.25%; P = .031); however, there was no significant difference between techniques when controlling for FPM preservation or detachment with submuscular nerve transposition (P = .139). There was no significant difference between techniques in time to return to sports (P = .729), although no reconstructions with FPM detachment and submuscular ulnar nerve transposition were available for RTP time analysis. Conclusion: There was no significant difference in the proportion of excellent Conway Scale outcomes or RTP time between the docking and modified Jobe techniques for UCL reconstruction when the FPM was preserved and routine submuscular ulnar nerve transposition was not performed.

DUAL-TASK BALANCE CONTROL IN ADOLESCENT ATHLETES FOLLOWING CONCUSSION

Background:Previous research has identified deficient dual-task balance control at the time of return to play (RTP) and possible worsening after RTP in older adolescents/young adults with concussion. These findings have not been investigated in younger patients with concussion.Hypothesis/Purpose:We hypothesized that concussed adolescents would have slower walking speed and increased medial-lateral (ML) center of mass (COM) movement, which would normalize by the time of RTP but worsen after resuming activity.Methods:13 adolescent concussion patients (7 male; age 10-17 years) were prospectively evaluated at their initial visit (IV) (mean 18, range 4-43 days post-concussion), at RTP clearance (mean 46, range 12-173 days post-concussion), and one month later (mean 26, range 20-41 days post-RTP) along with 11 controls (3 male) seen for similarly timed visits. Standing balance was assessed using range and root mean squared (RMS) COM motion in the anterior-posterior (AP) and ML directions during standing on both legs with eyes open while performing quiet standing, dual-task audio Stroop, side-to-side head turns, and side-to-side thumb tracking tasks. Dynamic balance was assessed using walking speed and COM ML range and velocity during walking alone and with side-to-side head turns and verbal fluency (reciting words starting with “F”) dual tasks. Patients were compared against controls using t-tests, and changes over time were evaluated using linear mixed-effects regression.Results:During standing, patients had higher COM ML RMS than controls at IV during head turns and higher COM AP range during thumb tracking. COM ML motion decreased from IV to RTP (head turns range -6.5mm, p=0.058; head turns RMS -16.8mm, p=0.002; thumb range 9.2mm, p=0.012) and increased from RTP to 1 month follow-up (head turns RMS +10.0mm, p=0.040; Stroop RMS +8.4mm, p=0.086).Patients walked slower than controls at IV during all tasks, and COM ML range was higher in patients vs. controls during verbal fluency at IV and RTP. Walking speed increased from IV to RTP during verbal fluency (+7.8cm/s, p=0.044), from RTP to post-RTP in single task walking (+6.1cm/s, p=0.041), and at each successive visit during head turns (+6.0cm/s and +6.5cm/s, p<0.07). COM ML range also decreased in patients from IV to RTP with verbal fluency (-14.7mm, p=0.011) and from RTP to post-RTP in single task walking ( 4.0mm, p=0.061).Conclusion:Adolescent concussion patients had deficits in static and dynamic balance control at initial presentation. This tended to improve by RTP and only worsened post-RTP for dual-task ML control during standing, suggesting that current conservative treatment protocols are appropriate.

OCULOMOTOR FUNCTION IN ADOLESCENT ATHLETES FOLLOWING CONCUSSION

Background:Visual impairments affect up to 90% of patients post-concussion. These impairments may include deficits in fixation accuracy, smooth pursuit, saccadic latencies, vergence, accommodation, and vestibule-ocular reflexes. Quantitative assessment of oculomotor function may provide a sensitive and objective measure of concussion diagnosis and recovery since coordinated eye movements require the use of diverse and widely dispersed areas of the brain. This study quantified oculomotor function over time in adolescents following concussion.Hypothesis/Purpose:We hypothesized that adolescent concussion patients would demonstrate deficits of oculomotor function that would resolve by the time of return to play (RTP) and remain stable after RTP.Methods:13 adolescent athletes diagnosed with mild to moderate concussion (7 male; mean age 15.1, SD 2.1, range 10-17 years) were prospectively evaluated at their initial visit (mean 18, range 4-43 days post-concussion), at the time of clearance to RTP (mean 46, range 12-173 days post-concussion), and one month later (mean 26, range 20-41 days after RTP). 11 controls without past concussion or injury (3 male; mean age 12.3, SD 3.1, range 8-17 years) were also tested at similar time points. Eye tracking was recorded as participants followed a target moving on a screen in predefined patterns related to sinusoid and trapezoid smooth pursuit, vergence, saccade, and anti-saccade. Metrics characterizing the speed, accuracy, and variability of tracking were compared between groups and visits using t-tests and linear mixed-effects regression.Results:At their initial visit, patients tended to have greater overshoot and greater variability in tracking compared with controls (Table 1.1). Overshoot and variability of tracking during sinusoid smooth pursuit (both overall variability and variability of overshoot) decreased from initial visit to RTP (Table 1.2). Undershoot during sinusoid smooth pursuit tended to decrease from RTP to 1-month follow-up. The rate of convergence in the distance vergence task increased while the rate of divergence decreased between these time points.Conclusion:The main oculomotor deficits observed in concussed adolescents related to overshoot and variability of tracking during sinusoid smooth pursuit. These deficits resolved by the time of RTP and generally remained stable or continued improving after RTP. These results suggest that oculomotor function recovers sufficiently under current conservative treatment protocols.Table 1.1.Comparison of concussed patients at initial visit vs. controls ConcussedInitial VisitMean (SD)Control Mean (SD)p-valueSaccade latency0.44 (0.07)0.45 (0.07)0.72Anti-saccade latency0.65 (0.12)0.62 (0.08)0.41Rate of convergence1.44 (0.31)1.51 (0.25)0.62Rate of divergence1.56 (0.17)1.55 (0.24)0.94Sinusoid peak phase lag10.40 (6.75)10.55 (1.80)0.95 Sinusoid mean SD of error 3.19 (1.95) 2.00 (0.91) 0.075 Sinusoid mean overshoot 4.72 (4.23) 2.16 (1.54) 0.075 Sinusoid mean undershoot3.07 (0.91)2.90 (0.29)0.57Sinusoid SD overshoot5.17 (4.84)2.30 (1.80)0.080Sinusoid SD undershoot3.35 (1.11)3.28 (0.38)0.83Sinusoid smooth pursuit involves a target moving in a sinusoidal pattern in a horizontal direction. A full period of movement covers 35.6 degrees over 2.4 seconds.Table 1.2.Change between visits for patients Coef (SE)RTP vs. IVp-valueCoef (SE)Follow-up vs. RTPp-valueSaccade latency0.008 (0.022)0.739-0.034 (0.023)0.139Anti-saccade latency-0.015 (0.045)0.729-0.069 (0.050)0.166Rate of convergence-0.073 (0.088)0.410 0.269 (0.097) 0.005 Rate of divergence-0.021 (0.154)0.889 -0.315 (0.172) 0.068 Sinusoid peak phase lag1.52 (1.97)0.441-1.88 (2.05)0.359Sinusoid mean SD of error -1.04 (0.53) 0.048 0.49 (0.52)0.348Sinusoid mean overshoot -1.97 (0.98) 0.045 0.43 (0.97)0.657Sinusoid mean undershoot-0.02 (0.10)0.818 -0.16 (0.09) 0.080 Sinusoid SD overshoot -2.59 (1.04) 0.013 0.86 (1.02)0.396Sinusoid SD undershoot-0.17 (0.29)0.5690.15 (0.29)0.610Sinusoid smooth pursuit involves a target moving in a sinusoidal pattern in a horizontal direction. A full period of movement covers 35.6 degrees over 2.4 seconds.

Adductor injuries in the National Basketball Association: an analysis of return to play and player performance from 2010 to 2019

ABSTRACT Objectives: 1) To evaluate return to play (RTP) timing in National Basketball Association (NBA) athletes following adductor injuries, and 2) to evaluate the effect of adductor injuries on player performance, game availability, and career longevity following RTP. Methods: Adductor injuries in NBA athletes from the 2009–2010 to 2018–2019 seasons were identified utilizing publicly available records via previously validated methodology. RTP time was calculated, and player performance and game availability were compared pre- vs. post-injury. Additionally, an injury-free control group matched for age, BMI, position, and experience was assembled to allow for comparisons in performance, availability, and career length. Results: In total, 79 adductor injuries across 65 NBA athletes were identified. The average injured player was 28.3 ± 4.0 years of age, and had 6.5 ± 4.2 seasons of NBA experience. Guards were injured more frequently than forwards or centers (49% vs 25% vs 25%, respectively). All players were able to RTP following first-time adductor injury after missing an average of 7.7 ± 9.8 games (median [IQR]: 4 [1–9]) and 16.9 ± 20.4 days (median [IQR]: 9 [3.5–20]). Twelve players (18.5%) suffered an adductor re-injury at a mean latency of 509.5 ± 503.9 days. Adductor injuries did not result in significant changes in any major statistical category (points, assists, rebounds, steals, blocks, turnovers, field goal percentage), player efficiency rating (PER), minutes/game, games/season, or a number of all-star selections (all P > 0.05) following RTP. Additionally, when compared to matched controls, no difference was found in pre- to post-injury change of PER, games/season, or minutes/game (all P > 0.05). Career longevity was not significantly different between groups (P = 0.44). Conclusion: Following adductor injury, NBA players returned to gameplay after missing an average of 16 to 17 days, or 7 to 8 games. Adductor injury did not affect player performance, nor game availability or career longevity.

High-grade intramuscular tendon disruption in acute hamstring injury and return to play in Australian Football players.

Recent literature has reported intramuscular tendon (IT) disruption is associated with longer return to play (RTP) following acute hamstring injury. Investigate whether an increase in hamstring injury severity involving high-grade IT disruption and proximal injury location is associated with longer RTP times in elite Australian Rules Football (AFL) players. Hamstring injury records and RTP times from one professional AFL club were obtained over six seasons. MRI of injuries was retrospectively reviewed by a musculo-skeletal radiologist blinded to RTP information. A simplified four-grade classification of acute hamstring injuries was developed based on IT disruption severity and proximodistal injury location. MR0 had no observable MRI tissue damage; MR1 involved muscle-tendon junction, myofascial and low-grade IT injuries; MR2 involved distal and/or single muscle high-grade IT injuries, and MR3 involved high-grade IT injuries of the proximal biceps femoris (BF) IT with concomitant injury to BF+ semitendinosus muscles. Forty-one injuries were available for analysis. Median RTP times were as follows: MR0, 14days; MR1, 21days; MR2, 35days; and MR3, 88days. For MRI-positive injuries (MR1, MR2, MR3), there was a significant difference in the distributions of RTP, with increased injury severity associated with increased RTP times (P<.001). The distributions of RTP were significantly different between MR1 vs MR2 (P=.008), MR1 vs MR3 (P=.002), and MR2 vs MR3 (P=.012). In elite AFL players, acute hamstring injuries with high-grade IT disruption identified on MRI were associated with increased times to RTP compared to injuries with low-grade or no IT disruption.

Mapping brain recovery after concussion: From acute injury to 1 year after medical clearance.

To test the hypothesis that concussion-related brain alterations seen at symptomatic injury and medical clearance to return to play (RTP) will have dissipated by 1 year after RTP. For this observational study, 24 athletes with concussion were scanned longitudinally within 1 week after injury, at RTP, and 1 year after RTP. A large control cohort of 122 athletes were also scanned before the season. Each imaging session assessed global functional connectivity (Gconn) and cerebral blood flow (CBF), along with white matter fractional anisotropy (FA) and mean diffusivity (MD). The main effects of concussion on MRI parameters were evaluated at each postinjury time point. In addition, covariation was assessed between MRI parameters and clinical measures of acute symptom severity and time to RTP. Different aspects of brain physiology showed different patterns of recovery over time. Both Gconn and FA displayed no significant effects at 1 year after RTP, whereas CBF and MD exhibited persistent long-term effects. The effects of concussion on MRI parameters were also dependent on acute symptom severity and time to RTP for all postinjury time points. This study provides the first longitudinal evaluation of concussion focused on time of RTP and 1 year after medical clearance, using multiple different MRI measures to assess brain structure and function. These findings significantly enhance our understanding of the natural course of brain recovery after a concussion.

Comparison of Symptomology, Symptom Resolution Time, and Return to Play Time between Concussions Sustained in the Same Academic Year

ObjectiveThe purpose of this study is to examine symptomology, symptom resolution time, and return to play (RTP) time between concussions sustained in the same academic year.BackgroundPrevious research shows that among those with a history of previous concussions, outcomes for a recurrent concussion are worse, especially when concussions occur within two weeks of each other. Despite this research, there has been little investigation into concussions that occur in the same academic year.Design/MethodsConcussion data was collected from the National Collegiate Athletic Association (NCAA) Injury Surveillance Program (ISP) during the 2009/10-2017/18 academic years. Concussions were reported by athletic trainers (ATs) and were included if the student-athlete sustained two concussions in the same academic year. Proportions and means of symptoms, symptom resolution time, and RTP time were calculated, and, as appropriate, McNemar’s tests and Wilcoxon sign-rank tests were used to compare these between the first and second concussions.ResultsOverall, 138 student-athletes sustained 276 concussions across 15 different sports a mean of 43 days apart (SD: 37.3). Fewer symptoms were reported in the second concussion compared to the first (4.3 vs. 5.2, respectively; p = 0.01). RTP time was, on average, five days longer for the second concussion (p = 0.01), and a larger proportion of second concussions resulted in participation restriction of ≥30 days (first: 7.3%, second: 26.8%; p &lt; 0.01). Symptom resolution time did not differ between the first and second concussions.ConclusionsAlthough the RTP time was greater in second concussions compared to first, symptom resolution time did not differ. This suggests that there may be a difference in AT management of second concussions, with a more conservative, extended RTP progression. Further research is needed to examine the association between time between concussions and differences in concussion presentation.

Observational Study of Prevention and Intervention Strategies That Help Speed Return to Play Post-Concussion in Division I College Football

ObjectiveWe present evidence that a neurovisual oriented training program is associated with decreased concussion incidence and faster return to play (RTP) post injury in this observational cohort study.BackgroundSports concussion has been in the public eye and has been associated with heightened fear concerning playing football and other collision based sports. Protecting from concussion and rehabilitating the brain after a concussion is a high priority for many sports medical practitioners as well as for athletes wanting to play. For these reasons researchers associated with the American Athletic Conference (AAC) have been monitoring concussion incidence in football.Design/MethodsThe 12 schools of the AAC were surveyed for 2014, 2015, and 2016 concerning football induced concussions.ResultsThe average seasonal concussion rate was 10.4 ± 1.02 concussions per year and average RTP time was 13.2 ± 1.21 days. In the one team where there was an aggressive neuro visual conditioning and rehabilitation post-concussion program employed the concussion rate was 3.0 ± 1.0 concussions per year and the RTP time was 6.5 ± 0.5 days. Both numbers are significantly lower than in the other AAC teams.ConclusionsThe current paper reports that there may be mitigation strategies that can be employed to decrease concussion incidence as well as aid in faster RTP times. Such attempts to make football safer are needed as brain injury has been associated with long term consequences. Improving safety and brain health through mitigation strategies along with rehabilitation methods may aid in keeping athletes safer during play and throughout the lifespan.

Return to Play Following Nonoperative Treatment of Partial Ulnar Collateral Ligament Injuries in Professional Baseball Players: A Critically Appraised Topic.

Clinical Scenario: Ulnar collateral ligament (UCL) injuries are highly prevalent in professional baseball players with the success of operative management being well known in the literature. Return to play (RTP) rates following nonoperative management of partial UCL injuries in professional baseball players are not well established in the literature. With a UCL tear being a potential career-ending injury, it is imperative that the best treatment option is provided to these throwing athletes. There is an increase in the incidence of UCL surgical rates and a lack of general agreement on nonoperative treatment of partial UCL injuries as reported by the American Shoulder and Elbow Surgeons in 2017. There is also a lack of clarity on when to initiate rehabilitation, which may be due to the limited amount of studies reporting success of RTP rates and time to RTP following conservative interventions of partial UCL injuries. Evidence on the RTP rates seen following conservative management of partial UCL tears injuries can help guide health care providers in deciding on the best treatment option for professional baseball athletes who desire to return to their athletic careers. These rates of RTP will add valuable objective input when determining if conservative management is the best choice. To determine the current evidence, inclusion criteria for the literature search consisted of RTP rates following conservative treatment in professional baseball players between inception and 2018. Clinical Question: Is there evidence for successful RTP rates in professional baseball players following conservative treatment of a UCL injury? Summary of Key Findings: Three retrospective studies met the inclusion criteria and were included. Of those, 2 reported RTP rates following a nonoperative rehabilitation program of a UCL injury, whereas 1 reported RTP rates after injection therapy in subjects who attempted a trial of conservative treatment. All 3 studies considered location and grade of UCL tear. Successful RTP rates (66%-100%) were reported in professional baseball players following nonoperative treatment of partial UCL injuries. Clinical Bottom Line: Current evidence supports high success with RTP rates up to 100% after nonoperative treatment of grade 1 UCL injuries in professional baseball players and between 66% and 94% for a grade 2 and above. Strength of Recommendation: There is level C evidence for high RTP rates following nonoperative treatment of partial UCL injuries in professional baseball players.

Concussions in the National Basketball Association: Analysis of Incidence, Return to Play, and Performance From 1999 to 2018.

Background:The effect of concussions on professional athletes has been investigated in many sports. However, few studies have evaluated concussions in National Basketball Association (NBA) players.Hypothesis:We hypothesized that concussion incidence has increased, yet the return-to-play (RTP) rate will remain high following the institution of the NBA concussion policy (NBACP). We also hypothesized that the incidence of repeat concussions will be similar to first occurrences and that player performance and game availability will not be significantly affected by sustaining a concussion.Study Design:Descriptive epidemiology study.Methods:Publicly available records were searched to identify all concussions from NBA seasons 1999-2000 to 2017-2018. Player demographics and information regarding career history were tabulated. Incidence of concussion and RTP timing were evaluated before and after institution of the NBACP (2011). Minutes per game and game score per minute were evaluated pre- versus postconcussion. Player availability and performance were also compared with an age-, body mass index–, position-, and experience-matched control group of players who did not sustain a concussion.Results:A total of 189 concussions were reported in the NBA from 1999 to 2018, with a mean ± SD incidence of 9.7 ± 7.3 concussions per season. Following implementation of the NBACP, incidence significantly increased from 5.7 ± 2.8 to 16.7 ± 7.5 concussions per season (P = .007). All players returned to play following first-time concussion after missing 7.7 ± 8.6 days and 3.5 ± 4.1 games. RTP time was not significantly different after implementation of the NBACP (games missed, P = .24; days missed, P = .27), and there was no difference in concussion-free time interval (P = .29). Game score per minute and minutes per game were not significantly affected by sustaining a concussion (both P > .05).Conclusion:Concussion incidence in NBA players is approximately 17 instances per season since the 2011 institution of a league-wide concussion policy. The number of reported concussions significantly increased following the policy, in line with trends seen in other professional sports leagues. Players have retained a high rate of RTP after 3 to 4 missed games. Player performance and availability are not affected by sustaining a concussion following successful RTP.

Short-Term Outcomes of Concussions in Major League Baseball: A Historical Cohort Study of Return to Play, Performance, Longevity, and Financial Impact.

Background:The short-term outcomes of concussions within Major League Baseball (MLB) warrant further consideration beyond a medical standpoint given that performance, career, and financial data remain unknown. The perception of this injury directly affects decision making from the perspective of both player and franchise.Purpose:To evaluate the effect of concussion on MLB players by (1) establishing return-to-play (RTP) time after concussion; (2) comparing the career length and performance of players with concussion versus those who took nonmedical leave; and (3) analyzing player financial impact after concussion.Study Design:Cohort study; Level of evidence, 3.Methods:Contracts, transactions, injury reports, and performance statistics from 2005 to 2017 were analyzed by comparing matched players who sustained a concussion versus those who took nonmedical leave. Of the 4186 eligible MLB players, 145 sustained concussions resulting in the activation of concussion protocol and 538 took nonmedical leave. RTP time was recorded. Career length was analyzed in reference to an experience-based stratification of full seasons remaining after the concussion. Changes in player performance and salary before and after concussion were compared with the same parameters for players who took nonmedical leave.Results:The mean RTP time was 26 days (95% CI, 20-32 days) for athletes with concussion and 8 days (95% CI, 6-10 days) for those who took nonmedical leave. Athletes with concussion had a mean of 2.8 full seasons remaining, whereas athletes who took nonmedical leave had 3.1 seasons remaining (P = .493). The probability of playing in the MLB after concussion compared with the nonmedical leave pool was not significantly lower (P = .534, log-rank test; hazard ratio, 1.108). Postconcussion performance decreased significantly in position players, including a lower batting average and decreased on-base percentage in the players with concussion compared with those returning from nonmedical leave. Players who sustained a concussion lost a mean of US$654,990 annually compared with players who took nonmedical leave.Conclusion:This study of the short-term outcomes after concussion in limited-contact MLB athletes demonstrates that concussions may not decrease career spans but may result in decreased performance in addition to financial loss when compared with matched controls who took nonmedical leave. In sports such as baseball that are not subject to repetitive head trauma, career spans may not decrease after a single concussive event. However, sentinel concussions have deleterious short-term effects on performance and compensation among MLB players.

Inflection points in longitudinal models: Tracking recovery and return to play following concussion.

The return to play (RTP) process may occur during longitudinal studies tracking recovery after concussion. This factor, which is often omitted within statistical designs, could affect the fit and overall interpretation of the statistical model. This article demonstrates the difference in results and interpretation between 2 linear mixed-model designs: (1) a between-group longitudinal (GROUP) analysis and (2) a between-group longitudinal model that used an inflection point to account for changes around the time of RTP (RTP analysis). These analyses were conducted on instrumented balance data collected on 23 concussed athletes and 25 controls over 8weeks following concussion. Total sway area and the range of mediolateral acceleration were used as outcome measures. No significant findings were found in the GROUP design for either outcome measure. In contrast, the RTP analysis revealed significant effects of time (P=.007) and RTP change (P=.007), and group*time (P=.028) and group*RTP change (P=.022) interactions for total sway area, and effects of group (P=.011), time (P=.010), and RTP change (P=.014), and group*time (P = .013) and group*RTP change interactions (P=.013) for range of mediolateral acceleration. For both outcomes, the RTP model fit the data significantly better on comparison of likelihood ratios (P≤.027). These results suggest that allowing for an inflection point in the statistical design may assist understanding of what happens around clinically meaningful time points. The choice of statistical model had a considerable effect on the interpretation of findings, and provokes discussion around the best method for analyzing longitudinal datasets when important clinical time points like RTP exist.

O 032 - Investigating the gender-related response of muscle fatigue of the medial longitudinal arch height in healthy young

Ankle sprain is a common injury in professional soccer, but to date midtarsal sprain has not been investigated in this context. The purpose of this study was to determine the prevalence of midtarsal sprain by MRI and to assess its impact on the time of return to play in professional soccer players.We included 52 professional soccer players who underwent 59 MRI examinations after acute ankle trauma between January 2012 and September 2019. Images were retrospectively reviewed in consensus by two radiologists for assessment of midtarsal sprain and ankle sprain. Ligaments were graded as i) normal, ii) partial tear, or iii) complete tear. Time to return to play (RTP) for each athlete was retrieved from team medical records. A Kruskal-Wallis test and Dunn’s pairwise tests were used to calculate differences in RTP time between groups with i) isolated midtarsal sprain, ii) isolated lateral ankle sprain, and iii) combined midtarsal and lateral ankle sprain.MRI revealed isolated ankle sprain in 24 of 59 MRI examinations (40.6 %). Acute midtarsal ligament injury was present in 15 examinations (25.4 %). Four of the 15 examinations (26.7 %) had isolated midtarsal injuries and eleven of the 15 examinations (73.3 %) had concomitant ankle sprain. RTP time was 39 days (range 9–70 days) for isolated midtarsal sprain. RTP time was significantly higher for athletes with combined ankle and midtarsal sprain (47 days, range 15–74 days) when compared to athletes with isolated ankle sprain (24 days, range 2–59 days) (p = .019).Our MRI study reveals that midtarsal sprain is a frequent injury in professional soccer players with ankle sprain. Midtarsal ligament findings on MRI combined with evidence of lateral ankle sprain is associated with a longer time of return to play compared to isolated lateral ligament injuries.Retrospective study, observational study.

Neurofilament light and tau as blood biomarkers for sports-related concussion.

ObjectiveTo compare neurofilament light (NfL) and tau as blood-based biomarkers for acute sports-related concussion (SRC) and determine whether their concentrations at different time points after the injury are associated with prolonged time to return to play (RTP).MethodsA total of 288 professional hockey players were followed longitudinally from September 1, 2012, to April 30, 2015. Data collection and biomarker analyses were conducted between 2015 and 2017. Associations were tested between blood concentrations of NfL and tau, and RTP time. Serum concentrations of S100B and neuron-specific enolase (NSE) were also measured for comparison.ResultsOf 288 players, 105 sustained an SRC. Of these, 87 underwent blood sampling 1, 12, 36, and 144 hours after SRC and at the RTP time point. Serum NfL concentrations 1, 12, 36, and 144 hours after SRC were related to prolonged RTP time, and could separate players with RTP >10 days from those with RTP ≤10 days (area under the receiver operating characteristic curve [AUROC] 0.82). Also, serum NfL 144 hours after SRC discriminated players who resigned from the game due to persistent postconcussion symptoms (PCS) from those who returned to play (AUROC 0.89). Plasma tau 1 hour after SRC was related to RTP but less strongly than NfL, while S100B and NSE showed no such associations.ConclusionSerum NfL outperformed tau, S100B, and NSE as a biomarker for SRC. From a clinical standpoint, serum NfL may be useful to identify individuals at risk of prolonged PCS, and may aid in biomarker-informed decisions with regard to when RTP should be considered.

How much is enough in rehabilitation? High running workloads following lower limb muscle injury delay return to play but protect against subsequent injury

ObjectivesExamine the influence of rehabilitation training loads on return to play (RTP) time and subsequent injury in elite Australian footballers. DesignProspective cohort study. MethodsInternal (sessional rating of perceived exertion: sRPE) and external (distance, sprint distance) workload and lower limb non-contact muscle injury data was collected from 58 players over 5 seasons. Rehabilitation periods were analysed for running workloads and time spent in 3 rehabilitation stages (1: off-legs training, 2: non-football running, 3: group football training) was calculated. Multi-level survival analyses with random effects accounting for player and season were performed. Hazard ratios (HR) and 95% confidence intervals (CI) for each variable were produced for RTP time and time to subsequent injury. ResultsOf 85 lower limb muscle injuries, 70 were rehabilitated to RTP, with 30 cases of subsequent injury recorded (recurrence rate=11.8%, new site injury rate=31.4%). Completion of high rehabilitation workloads delayed RTP (distance: >49,775m [reference: 34,613–49,775m]: HR 0.12, 95%CI 0.04–0.36, sRPE: >1266AU [reference: 852–1266AU]: HR 0.09, 95%CI 0.03–0.32). Return to running within 4days increased subsequent injury risk (3–4days [reference: 5–6 days]: HR 25.88, 95%CI 2.06–324.4). Attaining moderate-high sprint distance (427–710m) was protective against subsequent injury (154–426m: [reference: 427–710m]: HR 37.41, 95%CI 2.70–518.64). ConclusionsTraining load monitoring can inform player rehabilitation programs. Higher rehabilitation training loads delayed RTP; however, moderate-high sprint running loads can protect against subsequent injury. Shared-decision making regarding RTP should include accumulated training loads and consider the trade-off between expedited RTP and lower subsequent injury risk.

Following ulnar collateral ligament reconstruction, professional baseball position players return to play faster than pitchers, but catchers return less frequently

Although much as been done to characterize trends of medial ulnar collateral ligament (UCL) reconstruction in pitchers, outcomes in position players (PPs) (non-pitchers) remain undefined in the current literature. Three resources were combined to identify all known Major League Baseball and Minor League Baseball (MiLB) PPs who have ever undergone UCL reconstruction. A multitude of player and surgical variables were included. Trends over time were analyzed collectively, based on level of play, revision status (primary vs revision), and position. Additional comparisons were made with a known cohort of professional baseball pitchers having undergone UCL reconstruction. We identified 168 UCL reconstructions in professional PPs. The annual rate of primary UCL reconstruction rose significantly from 1984 to 2015 (P < .001), and the proportion of cases performed in MiLB PPs (vs Major League Baseball PPs) increased steadily (P < .001). Of PPs, 75.5% returned to play at any level at a mean of 342 days. Catchers demonstrated the lowest return-to-play (RTP) rate (58.6%) compared with infielders (75.6%) and outfielders (88.9%). The overall revision rate was low, at 4.8%. Compared with pitchers, PPs demonstrated a lower rate of RTP (75.5% for PPs vs 83.7% for pitchers, P = .040) but shorter RTP times for those able to return (342 days for PPs vs 435 days for pitchers, P < .001). The incidence of UCL reconstruction in PPs continues to rise, a trend that is significantly more pronounced at the MiLB level. Although PPs (particularly catchers) are less likely to return to professional baseball compared with pitchers, those who are able to RTP do so more rapidly.

Athletic pubalgia: Return to play after targeted surgery.

Surgery for athletic pubalgia usually consists in abdominal wall repair combined with routine bilateral adductor tenotomy. We currently confine the surgical procedure to the injured structure(s) (abdominal wall only, adductor tendon only, or both) to limit morbidity and expedite recovery. Outcomes of this à la carte approach are unclear. The objectives of this retrospective study were to determine the return to play (RTP) time, evaluate the potential influence of injury location, and assess the frequency of recurrence or contralateral involvement. À la carte surgery for athletic pubalgia is associated with similar RTP times as the conventional procedure and is not followed by recurrence. Consecutive adults younger than 40 years of age who underwent surgery for athletic pubalgia with injury to the abdominal wall and/or adductor attachment sites between 2009 and 2015 were included. Patients with intra-articular hip disorders, isolated pubic symphysis involvement, or herniation were not eligible. The diagnosis was established clinically then confirmed by at least one imaging technique (ultrasonography plus either a radiograph of the pelvis or magnetic resonance imaging of the pelvis). The criterion for performing surgery was failure of appropriate conservative therapy followed for at least 3 months. Of the 27 included patients, eight had abdominal wall involvement only, seven adductor tendon involvement only, and 12 both. Overall, 25 (92.6%) patients returned to play at their previous level, after a mean of 112±38 days (range, 53-223 days), and experienced no recurrence during the 1-year follow-up. Mean RTP time was significantly shorter in the group with abdominal wall injury only (91.1±21.0 days) compared to the groups with adductor tendon injury only (101.7±42.0 days) or combined injuries (132.5±39.0) (p=0.02). In patients with athletic pubalgia, à la carte surgery confined to the injured structure(s) produces excellent RTP outcomes. RTP time is shortest in patients with isolated lower abdominal wall injuries. IV, retrospective study with no control group.

Performance-based Outcomes among American Professional Athletes Following Microfracture of the Knee: A Cross-sport Analysis

Objectives:Damage to the articular cartilage of the knee is a common and potentially career-threatening injury among professional athletes. Microfracture is a technique frequently used to treat chondral defects, but the potential benefits of this procedure in the elite athlete population remain unclear. This study sought to assess outcomes after microfracture of the knee among American professional athletes in different sports.Methods:Major League Baseball (MLB), National Basketball Association (NBA), National Football League (NFL), and National Hockey League (NHL) athletes who underwent primary unilateral microfracture of the knee while on the active roster of a professional team and had a definitive date of surgery were identified through a well-established algorithmic approach based on public sources. Demographic information, as well as both pre- and post-surgery regular season player statistics, was compiled for each player. Successful return-to-play (RTP) was defined as returning for at least one professional regular season game after surgery. RTP time was defined as the number of days elapsed between date of surgery and date of first professional game back. Performance scores were calculated for each sport using previously established scoring systems. Players across different sports were compared by adjusting for season and career length differences between sports and by calculating percent change in performance.Results:A total of 131 professional athletes treated with microfracture from 1991 to 2015 met the inclusion criteria. Of these athletes, 103 (78.6%) successfully returned to play (Figure 1). Average time to RTP was 293±146 days. A player’s total career games started-to-games played ratio (GS:GP) before surgery was a significant positive independent predictor of RTP (p=0.039). NBA athletes who returned showed a significant reduction in adjusted games played during their first season post-surgery (61) compared to baseline (100) (p<0.0001). NBA and MLB athletes demonstrated significantly decreased performance one season after surgery (p=0.029 and p=0.002, respectively), and NBA athletes also demonstrated significantly decreased performance during post-operative seasons 2-3 (p=0.024) (Figure 2). BMI, age, career experience (years), games played during index season and total pre-operative career, and GS:GP during index season and total pre-operative career were not found to be predictors of RTP time, career length after surgery (years and games played), or change in performance score.Conclusion:Microfracture of the knee is a serious procedure that has the potential to negatively impact a professional athlete’s career. NFL athletes demonstrated the lowest probability of returning after surgery (71.1%), but for those who returned, performance was recoverable to baseline. NBA athletes had a higher-than-average probability of returning to play (82.4%), but those who returned showed a significant decline in performance one season after surgery that was sustained 2-3 seasons post-surgery, and a reduction in games played one season after surgery that was recoverable to baseline by seasons 2-3 post-surgery. Given the small sample size for NHL, microfracture of the knee may be uncommon in these athletes and definitive conclusions cannot be made. The findings of this study demonstrate that outcomes following microfracture vary significantly depending on sport, which is likely due in part to differences in sport-specific tasks. Figure 1:Return-to-play rates following primary unilateral microfracture of the knee for American professional athletes. *MLB athletes returned to play at a significantly higher rate than athletes of all other sports (p=0.013). **NFL athletes returned to play at a significantly lower rate than athletes of all other sports (p=0.017). Figure 2:Performance-based outcomes among American professional athletes following primary unilateral knee microfracture surgery. “Denotes significant difference (p<0.135) compared with pre-surgery season (baseline) for each athlete in cohort. NHL excluded due to small sample size.

Criteria for Progressing Rehabilitation and Determining Return-to-Play Clearance Following Hamstring Strain Injury: A Systematic Review.

Rehabilitation progression and return-to-play (RTP) decision making following hamstring strain injury (HSI) can be challenging for clinicians, owing to the competing demands of reducing both convalescence and the risk of re-injury. Despite an increased focus on the RTP process following HSI, little attention has been paid to rehabilitation progression and RTP criteria, and subsequent time taken to RTP and re-injury rates. The aim of this systematic review is to identify rehabilitation progression and RTP criteria implemented following HSI and examine the subsequent time taken to RTP and rates of re-injury. A systematic literature review of databases MEDLINE, CINAHL, SPORTDiscus, Cochrane Library, Web of Science and EMBASE was conducted to identify studies of participants with acute HSI reporting time taken to RTP and rates of re-injury after a minimum 6-month follow-up. General guidelines and specific criteria for rehabilitation progression were identified for each study. In addition, RTP criteria were identified and categorised as performance tests, clinical assessments, isokinetic dynamometry or the Askling H-test. Nine studies were included with a total of 601 acute HSI confirmed by clinical examination or magnetic resonance imaging within 10days of initial injury. A feature across all nine studies was that the injured individual's perception of pain was used to guide rehabilitation progression, whilst clinical assessments and performance tests were the most frequently implemented RTP criteria. Mean RTP times were lowest in studies implementing isokinetic dynamometry as part of RTP decision making (12-25days), whilst those implementing the Askling H-test had the lowest rates of re-injury (1.3-3.6%). This systematic review highlights the strong emphasis placed on the alleviation of pain to allow HSI rehabilitation progression, and the reliance on subjective clinical assessments and performance tests as RTP criteria. These results suggest a need for more objective and clinically practical criteria, allowing a more evidence-based approach to rehabilitation progression, and potentially reducing the ambiguity involved in the RTP decision-making process.