Concussion Is Associated With Increased Odds of Acute Lower-Extremity Musculoskeletal Injury Among National Basketball Association Players

Overview of Treatment Options for Mild Traumatic Brain Injury: A Literature Review

The incidence and prevalence of concussion, a type of mild traumatic brain injury (mTBI), have steadily increased among athletes, both students and professionals, across a wide variety of sports, including, but not limited to, swimming, tennis, football, and boxing. Recent data have demonstrated that sports are one of the leading causes of concussions among student athletes. While the exact mechanism of concussion onset has yet to be fully elucidated, data suggest that the pathophysiology involves rotational acceleration and deceleration of the brain, leading to axon tearing and disturbance in the metabolic cascade of glucose. Concussive events can have debilitating effects on an athlete, including chronic traumatic encephalopathy (gradual degeneration of brain tissue) that is related to personality changes, emotional disorders, and even dementia. Common symptoms associated with concussion include dizziness, nausea, vomiting, and headaches. The physical assessment consists of a combination of tools involving the mental status examination, vital signs, cervical spine exam, eye exam, and neurological testing. The use of osteopathic manipulative medicine (OMM), pharmacotherapy, hyperbaric oxygen therapy (HBOT), aerobic exercise, balance, and/or vestibular therapy are many common treatment approaches for concussion and post-concussion sequelae. This literature review aims to provide insight into concussions, the current treatment options available, and the new developments in concussions per the Amsterdam 2022 International Consensus Statement on Concussion in Sport published in 2023.

Editorial Commentary: Load Management Is Essential to Prevent Season-Ending Injuries in the National Basketball Association

Each season, National Basketball Association (NBA) athletes subject themselves to a physical season including a minimum of 82 games, intense travel, participation during holidays, innumerable training sessions, and for some, playoffs continuing into June. Intensity and fatigue may contribute to a high rate of injuries, and recent literature has suggested that primary risk factors for season-ending injuries are minutes played per game and later season games. Scheduled periods of rest, or load management, reduce the physiological load a player endures during a grueling season. Disadvantages of load management may include decrements in individual skill, team competitiveness, and financial issues, including disappointed fans. Thus, in 2023, the NBA instituted the Player Participation Policy (PPP) placing stipulations on load management by asking teams to balance player rest between home and away games and to refrain from long-term shutdowns of player participation for nonmedical reasons. From a medical standpoint, safeguarding athlete health is of paramount importance. Managing the workload of NBA players may have numerous player benefits and must be achieved while mitigating the disadvantages.

Concussions: A Review of Physiological Changes and Long-Term Sequelae

A concussion is a type of mild traumatic brain injury (mTBI). It is prevalent among athletes across a wide variety of sports. The exact mechanism of a concussion is unknown, but it is currently accepted that the acceleration and deceleration of the brain is the insult causing disturbances in activity. The most common symptoms of concussions include but are not limited to dizziness, nausea, vomiting, and headaches. With repetitive concussive injuries, athletes can experience permanent changes such as chronic traumatic encephalopathy (gradual degeneration of brain tissue), which can lead to personality changes and memory deficits. This literature review aims to provide insight into concussions and the evaluation of physiological changes and long-term sequelae. A comprehensive literature search was performed from April 2012 to April 2022 using PubMed/MEDLINE (Medical Literature Analysis and Retrieval System Online) and Embase databases. Nineteen articles were finally included in the literature review. The review shows that neuroimaging results demonstrated significant changes in the brain structure and function including alternations in the thalamus, hippocampus, corpus callosum, and the white matter, which can extend beyond the symptom amelioration. In addition, other approaches include brain metabolism, cerebral blood flow, and glucose utilization. Additional techniques include the evaluation of fatigue levels and the alterations in biomarkers, specifically IL-6. These approaches have demonstrated that consequences of concussions, including alternations in brain structure and function, can extend beyond an athlete's report of symptom resolution, and should be taken into consideration for return to play. The physiological changes present after a concussion have the potential to develop into long-term complications such as academic difficulty, cognitive decline, gut microbiome changes, gait changes, and increased risk of lower extremity injury. The findings in the literature review determine that is important to immediately address the symptoms of concussions to expedite treatment and prevent deleterious changes to the brain.

Characterization of Ankle Injuries and Associated Risk Factors in the National Basketball Association: Minutes Per Game and Usage Rate Associated With Time Loss

Background

Ankle injuries are more common in the National Basketball Association (NBA) compared with other professional sports.

Purpose/Hypothesis

The purpose of this study was to report the incidence and associated risk factors of ankle injuries in NBA athletes. It was hypothesized that factors associated with an increased physiologic burden, such as minutes per game (MPG), usage rate, and associated lower extremity injury, would be associated with increased ankle injury risk and time loss.

Study Design

Descriptive epidemiology study.

Methods

Ankle injury data from the 2015-2016 through 2020-2021 NBA seasons were evaluated. The truncated 2019-2020 season due to the COVID-19 pandemic was omitted. The primary outcome was the incidence of ankle injuries, reported per 1000 game-exposures (GEs). Secondary analysis was performed to identify risk factors for ankle injuries through bivariate analysis and multivariable logistic regression of player demographic characteristics, performance statistics, injury characteristics, and previous lower extremity injuries. Factors influencing the time loss after injury were assessed via a negative binomial regression analysis.

Results

A total of 554 ankle injuries (4.06 injuries per 1000 GEs) were sustained by NBA players over 5 NBA seasons, with sprain/strain the most common injury type (3.71 injuries per 1000 GEs). The majority of ankle injury events (55%) resulted in 2 to 10 game absences. The likelihood of sustaining an ankle injury was significantly associated with a greater number of games played (P = .029) and previous injury to the hip, hamstring, or quadriceps (P = .004). Increased length of absence due to ankle injury was associated with greater height (P = .019), MPG (P < .001), usage rate (P = .025), points per game (P = .011), and a prior history of foot (P = .003), ankle (P < .001), and knee injuries (P < .001).

Conclusion

The incidence of ankle injuries was 4.06 per 1000 GEs in professional basketball players. Games played and prior history of hip, hamstring, or quadriceps injuries were found to be risk factors for ankle injuries. Factors associated with physiologic burden such as MPG and usage rate were associated with an increased time loss after injury.

Risk of Lower Extremity Ligamentous Injury Following Concussion Diagnosis: A TriNetX Database Study

Background Concussion is one of the most frequently reported sports-related injuries in the United States; there is evidence that residual deficits in neurocognition may increase the risk of lower extremity musculoskeletal injury after concussion in high school, college, and professional athletes. The purpose of this study is to identify whether similar trends are identified in community-based populations.  Methods The TriNetX Research Network database was queried for patients 10-60 years old who experienced an ambulatory or emergency visit from 2018-2020. Cohorts were defined by patients seen for concussion and patients seen for other reasons. These cohorts were then propensity score matched based on significant differences in demographics; after matching, each cohort included 97,708 patients. The propensity score-matched cohorts were then evaluated to identify patients who experienced subsequent lower extremity ligamentous injury within 12 months. Results Patients with a history of concussion were more likely to experience posterior cruciate ligament (PCL) sprain (0.04% vs. 0.02%, risk ratio (RR)=1.79, p=.039), medial collateral ligament (MCL) sprain (0.18% vs. 0.08%, RR=2.355, p<.001), lateral collateral ligament (LCL) sprain (0.05% vs. 0.02%, RR=2.202, p=.003) and ankle sprain (1.05% vs. 0.47%, RR=2.265, p<.001). Conclusion Patients diagnosed with concussion were more likely to experience a lower extremity ligamentous injury when compared with patients who did not have concussion. Patients should be counseled regarding this increased risk and additional neuromuscular evaluation and injury prevention education may be indicated following concussion diagnosis.

Lower Extremity Musculoskeletal Injuries After Concussion in Collegiate Student-Athletes

BACKGROUND

An association has been identified between concussion and lower extremity musculoskeletal injury (LEMSKI) after return to sports participation. However, the collegiate student-athlete studies have relied on relatively small single-institution studies, which limits generalizability.

PURPOSE

To assess odds of, and time to, LEMSKI after concussion in US collegiate athletes, using the National Collegiate Athletic Association (NCAA) Injury Surveillance Program (ISP).

STUDY DESIGN

Descriptive epidemiology study.

METHODS

Data from the NCAA ISP during the 2010-2011 through 2019-2020 athletic seasons were considered for analysis. Frequency distributions were examined for details related to the initial and subsequent injuries (injuries to bone, bursa, joint, ligament, muscle, or tendon). Multivariable logistic regression models and random-effects Poisson regression models examined odds of time loss (TL) and non-time loss (NTL) LEMSKI after concussion, as well as the time interval between initial concussion and subsequent LEMSKI in a single athletic season, or initial musculoskeletal injury (MSKI) and subsequent LEMSKI in a single athletic season. Analyses were performed separately for football and other sports.

RESULTS

A total of 31,556 initial injuries were recorded (football: 11,900; other sports: 19,656), which were followed by 0 or 1 injury in the same season. Overall, first injury type was not a significant predictor of subsequent LEMSKI, although certain contrasts yielded significant estimates. In football, the odds of NTL LEMSKI were higher after concussion than after upper extremity MSKI (UEMSKI; adjusted odds ratio [OR_Adj], 1.56; 95% CI, 1.06-2.31). In football, the odds of TL LEMSKI were lower after concussion than after UEMSKI (OR_Adj, 0.71; 95% CI, 0.51-0.99). No other significant effect estimates were observed for football or other sports.

CONCLUSION

First injury type, either concussion or upper extremity, was not associated with an elevated risk of LEMSKI. Specifically, the results of this study did not identify an elevated odds of LEMSKI after a concussion. However, the authors observed greater odds of NTL LEMSKI and lower odds of TL LEMSKI in football.

Performance Is Regained Within 2 Seasons After Quadriceps Tendon Tears in National Basketball Association Players

Purpose

To characterize quadriceps tendon injuries over 30 National Basketball Association (NBA) seasons and assess the effects on player performance upon return to play.

Methods

Partial and complete quadriceps tendon tears in NBA players between the 1990-1991 and 2021-2022 seasons were queried from a publicly available database. The primary outcomes were changes in player performance statistics obtained from each player's preindex season and first 2 postindex seasons. These interseason changes were compared with the changes of a healthy control cohort. Each injured player was matched with 2 controls using position, career length and win shares by season. The secondary measure of this study was the rate of return to play.

Results

Nine quadriceps tendon tears (6 partial, 3 complete) were identified in NBA players. Seven (78%) of the players returned to play in NBA games, missing 50 ± 30 games and 214 ± 112 calendar days on average. Comparisons between these player's preindex and first postindex seasons revealed significant declines in games played (73.2 ± 6.6 vs 41.8 ± 10.8, P = .009) and minutes per game (27.2 ± 2.9 vs 23.0 ± 3.7, P = .042). When compared with controls, only the decrease in games played was significant (-31.3 ± 7.6 vs 1.4 ± 8.2, P = .004). These findings were consistent when comparing preindex and second postindex seasons (games played: 79.6 ± 1.9 vs -28.4 ± 5.4, P = .006; minutes per game: 29.3 ± 2.6 vs 51.2 ± 4.6, P = .003). All other player performance metrics including player efficiency rating returned to near-baseline levels in the first 2 seasons after injury.

Conclusion

NBA players with quadriceps tendon tears return to play in 78% of cases. These athletes achieved preinjury levels of performance within 1 to 2 seasons, but with reduced games played per season.

Level of Evidence

IV, therapeutic case series.

Effect of a Condensed NBA Season on Injury Risk: An Analysis of the 2020 Season and Player Safety

Background:

Health and safety concerns surrounding the coronavirus 2019 (COVID-19) pandemic led the National Basketball Association (NBA) to condense and accelerate the 2020 season. Although prior literature has suggested that inadequate rest may lead to an increased injury risk, the unique circumstances surrounding this season offer a unique opportunity to evaluate player safety in the setting of reduced interval rest.

Hypothesis:

We hypothesized that the condensed 2020 NBA season resulted in an increased overall injury risk as compared with the 2015 to 2018 seasons.

Study Design:

Descriptive epidemiology study.

Methods:

A publicly available database, Pro Sports Transactions, was queried for injuries that forced players to miss ≥1 game between the 2015 and 2020 seasons. Data from the 2019 season were omitted given the abrupt suspension of the league year. All injury incidences were calculated per 1000 game-exposures (GEs). The primary outcome was the overall injury proportion ratio (IPR) between the 2020 season and previous seasons. Secondary measures included injury incidences stratified by type, severity, age, position, and minutes per game.

Results:

A total of 4346 injuries occurred over a 5-season span among 2572 unique player-seasons. The overall incidence of injury during the 2020 season was 48.20 per 1000 GEs but decreased to 39.97 per 1000 GEs when excluding COVID-19. Despite this exclusion, the overall injury rate in 2020 remained significantly greater (IPR, 1.42 [95% CI, 1.32-1.52]) than that of the 2015 to 2018 seasons (28.20 per 1000 GEs). On closer evaluation, the most notable increases seen in the 2020 season occurred within minor injuries requiring only a 1-game absence (IPR, 1.53 [95% CI, 1.37-1.70]) and in players who were aged 25 to 29 years (IPR, 1.57 [95% CI, 1.40-2.63]), averaging ≥30.0 minutes per game (IPR, 1.67 [95% CI, 1.47-1.90]), and playing the point guard position (IPR, 1.67 [95% 1.44-1.95]).

Conclusion:

Players in the condensed 2020 NBA season had a significantly higher incidence of injuries when compared with the prior 4 seasons, even when excluding COVID-19–related absences. This rise is consistent with the other congested NBA seasons of 1998 and 2011. These findings suggest that condensing the NBA schedule is associated with an increased risk to player health and safety.

Knee Injuries and Associated Risk Factors in National Basketball Association Athletes

Purpose

To determine structural knee injury rates and to identify risk factors and the number of games missed associated with these injuries in National Basketball Association (NBA) players from the 2015 to 2020 seasons.

Methods

Publicly available player records of active NBA players between the 2015 and 2020 seasons (excluding the shortened 2019 season) were reviewed to identify players with a knee injury associated with missing one or more games. Player demographics, anthropometric measurements, statistics, injury characteristics, and history of other lower-extremity injuries were recorded. We sought factors associated with having a structural knee injury in bivariate analysis and multivariable logistic regression. Negative binomial regression was conducted to evaluate factors associated with the total number of games missed.

Results

Two hundred twelve players (of 1,011, 21%) sustained a structural knee injury. Accounting for potential confounders, having a structural knee injury was associated with more minutes per game played (odds ratio [OR] 1.1; 95% confidence interval [CI] 1.0-1.2; P = .002), a greater usage rate (OR 1.1; 95% CI 1.0-1.2; P = .004), and a lower player efficiency rating (OR 0.94; 95% CI 0.89-1.0; P = .041). A greater number of missed games was associated with more minutes per game (regression coefficient [RC] 0.065; 0.028-0.10; P = .001), fewer points per game (RC –0.078; –0.14 to –0.017; P = .013), and greater usage rate (RC 0.032; 0.0040-0.060; P = .025).

Conclusions

Structural knee injuries occurred in 21% of players in this study with an overall rate of 5.42 injuries per 1,000 game exposures. Significant risk factors associated with injury were minutes per game, usage rate, and true shooting percentage. Player efficiency was significantly associated with a decreased risk of injury. Increased minutes per game and usage rate were significantly associated with a longer duration of game loss.

Level of Evidence

Level IV, case series.

Concussion is not associated with elevated rates of lower-extremity musculoskeletal injuries in National Football League Players

OBJECTIVE

Emerging evidence has identified an ~2x elevated risk of musculoskeletal (MSK) injury in the year following a concussion. Most of these studies have examined a single college/university athletic department and may lack generalizability to professional sports. Therefore, the purpose of this study was to assess the odds of post-concussion MSK injury utilizing publicly available National Football League (NFL) injury reports.

METHODS

Concussions were identified through a review of published NFL injury reports during the 2015, 2016, and 2017 regular seasons. Concussed players were matched by team and position, and injuries were tracked for both groups for the remainder of the season. A chi-square analysis compared the frequency of MSK injury in both groups and a Cox Proportional Hazard model calculated the risk of sustaining a subsequent MSK injury.

RESULTS

There were 322 concussed NFL players who met inclusion criteria and were successfully matched. From the time of concussion through the remainder of the season, 21.4% of the concussed players were injured and 26.4% of control participants were injured. There was no difference in MSK injury rates (p = 0.166), and the relative risk ratio was 0.90 for subsequent injury in the concussion group. There was no difference in the time to event for subsequent MSK between the two groups (p = 0.123).

CONCLUSION

The primary finding of this study was no elevated risk of post-concussion MSK in NFL football players.

An 8-Week Neuromuscular Training Program After Concussion Reduces 1-Year Subsequent Injury Risk: A Randomized Clinical Trial

BACKGROUND

Existing data suggest that after concussion, athletes experience an increased risk of subsequent injury. Exploring methods that may reduce injury risk after successful postconcussion return to play may lead to new treatment approaches.

PURPOSE

To examine the efficacy of a neuromuscular training (NMT) intervention on acute sports-related time-loss injury over the subsequent year relative to standard of care.

STUDY DESIGN

Randomized clinical trial; Level of evidence, 1.

METHODS

A total of 27 youth athletes were assessed initially postconcussion (median, 7 days postconcussion; interquartile range [IQR], 5-10) and after return-to-play clearance (median, 40 days postconcussion; IQR, 15-52). After return-to-play clearance, they were randomly assigned to NMT intervention (n = 11; mean ± SD age, 14.7 ± 1.7 years; 36% female) or standard of care (n = 16; mean ± SD age, 15.3 ± 1.8 years; 44% female). The intervention (duration, 8 weeks; frequency, 2 times per week) included guided strength exercises with landing stabilization focus. Standard of care received no recommendations. For the subsequent year, athletes prospectively completed a monthly log of sports-related injuries and organized sports competitions.

RESULTS

During the first year after postconcussion return-to-play clearance, sports-related time-loss injuries were more common among standard of care relative to NMT intervention (75% [95% CI, 48%-93%] vs 36% [95% CI, 11%-69%]). After adjusting for age and sex, the hazard of subsequent injury in the standard-of-care group was 3.56 times (95% CI, 1.11-11.49; P = .0334) that of the NMT intervention group. Sports participation was similar between NMT intervention and standard of care during the year-long monitoring period (hours of organized sports per month; median, 12 [IQR, 2.6-32.1] vs 15.6 [IQR, 3.5-105.9]; P = .55). The age- and sex-adjusted incidence of injuries was 10.2 per 1000 competitive exposures (95% CI, 3.7-28.4) in the standard-of-care group as opposed to 3.4 per 1000 (95% CI, 0.9-13.4) in the NMT intervention group. After adjusting for age and sex, incidence of injuries was higher for standard of care vs NMT intervention (rate ratio, 2.96 [95% CI, 0.89-9.85]; P = .076).

CONCLUSION

Although preliminary, our findings suggest that an NMT intervention initiated after return-to-play clearance may significantly reduce sports-related time-loss injuries over the subsequent year.

REGISTRATION

NCT03917290 (ClinicalTrials.gov identifier).

Lower Extremity Injury After Return to Sports From Concussion: A Systematic Review

Background:

Recent studies have suggested increased rates of lower extremity (LE) musculoskeletal injury after a diagnosed concussion, although significant heterogeneity exists.

Purpose:

To examine the current body of research and determine whether there is an increased risk for LE musculoskeletal injury after a concussion and to identify populations at an increased risk.

Study Design:

Systematic review; Level of evidence, 3.

Methods:

A systematic review of current literature using MEDLINE and PubMed databases was performed. Keywords included concussion, athlete, lower extremity injury, and return to sport. Inclusion criteria required original research articles written in the English language examining the rate of LE injuries after a diagnosed concussion.

Results:

A total of 13 studies involving 4349 athletes (88.1% male and 11.9% female; mean age, 19.8 years) met inclusion criteria. Athletes were classified as high school (46.1%), collegiate (17.0%), or professional (36.9%). Of the 13 studies, 4 demonstrated an increased risk of LE injury within 90 days of a diagnosed concussion (odds ratio [OR], 3.44; 95% CI, 2.99-4.42), and 6 revealed an elevated risk of injury within 1 year of concussion (OR, 1.85; 95% CI, 1.73-2.84). Increased risk was seen in professional (OR, 2.49; 95% CI, 2.40-2.72) and collegiate (OR, 2.00; 95% CI, 1.96-2.16) athletes compared with high school athletes (OR, 0.97; 95% CI, 0.89-1.05). A stepwise increase in risk of sustaining an LE injury was observed with multiple concussions, with increasing risk observed from ≥2 (OR, 2.29; 95% CI, 1.85-2.83) to ≥3 (OR, 2.86; 95% CI, 2.36-3.48) career concussions.

Conclusion:

An increased incidence of LE injuries was observed at 90 days and 1 year after the diagnosis of a concussion. Higher levels of competition, such as at the collegiate and professional levels, resulted in an increased risk of sustaining a subsequent LE injury after a diagnosed concussion. These results suggest an at-risk population who may benefit from injury prevention methods after a concussion. Future studies should focus on identifying which injuries are most common, during what time period athletes are most vulnerable, and methods to prevent injury after return to sports.

Concussion in National Football League Athletes Is Not Associated With Increased Risk of Acute, Noncontact Lower Extremity Musculoskeletal Injury

Background:

Impaired neuromuscular function after concussion has recently been linked to increased risk of lower extremity injuries in athletes.

Purpose:

To determine if National Football League (NFL) athletes have an increased risk of sustaining an acute, noncontact lower extremity injury in the 90-day period after return to play (RTP) and whether on-field performance differs pre- and postconcussion.

Study Design:

Cohort study, Level of evidence, 3.

Methods:

NFL concussions in offensive players from the 2012-2013 to the 2016-2017 seasons were studied. Age, position, injury location/type, RTP, and athlete factors were noted. A 90-day RTP postconcussive period was analyzed for lower extremity injuries. Concussion and injury data were obtained from publicly available sources. Nonconcussed, offensive skill position NFL athletes from the same period were used as a control cohort, with the 2014 season as the reference season. Power rating performance metrics were calculated for ±1, ±2, and ±3 seasons pre- and postconcussion. Conditional logistic regression was used to determine associations between concussion and lower extremity injury as well as the relationship of concussions to on-field performance.

Results:

In total, 116 concussions were recorded in 108 NFL athletes during the study period. There was no statistically significant difference in the incidence of an acute, noncontact lower extremity injury between concussed and control athletes (8.5% vs 12.8%; P = .143), which correlates with an odds ratio of 0.573 (95% CI, 0.270-1.217). Days (66.4 ± 81.9 days vs 45.1 ± 69.2 days; P = .423) and games missed (3.67 ± 3.0 vs 2.9 ± 2.7 games; P = .470) were similar in concussed athletes and control athletes after a lower extremity injury. No significant changes in power ratings were noted in concussed athletes in the acute period (±1 season to injury) when comparing pre- and postconcussion.

Conclusion:

Concussed, NFL offensive athletes did not demonstrate increased odds of acute, noncontact, lower extremity injury in a 90-day RTP period when compared with nonconcussed controls. Immediate on-field performance of skill position players did not appear to be affected by concussion.