Biomechanics and situational patterns associated with anterior cruciate ligament injuries in the National Basketball Association (NBA)

A Systematic Video Analysis of Anterior Cruciate Ligament Injuries in Professional Female Basketball Players

BACKGROUND

Anterior cruciate ligament (ACL) injuries are common in female basketball players, who have a 2 to 3 times higher risk for an ACL injury than their male counterparts. Improving our understanding of the situations and biomechanics that result in an ACL injury in basketball players may support the design of more effective programs to mitigate the injury risk.

PURPOSE

To describe the injury mechanisms, situational patterns, and biomechanics of ACL injuries during matches in professional female basketball players.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A total of 105 ACL injuries in professional female European basketball leagues from the 2018 to 2023 seasons were identified. There were 41 (39%) injury videos analyzed for injury mechanisms and situational patterns, while biomechanical analysis was possible in 33 cases. There were 3 independent reviewers who rated each video. Data according to player position, phase of the match, and location on the court were also evaluated (n = 41). Analysis regarding neurocognitive perturbation was assessed in 41 cases (100%).

RESULTS

Most injuries (n = 28 [68%]) occurred during offensive possession. Indirect contact injuries were more prevalent (n = 23 [56%]) than noncontact injuries (n = 18 [44%]). Overall, 3 main situational patterns constituted 95% of injuries: offensive cut (n = 20 [49%]), defensive cut (n = 12 [29%]), and landing from a jump (n = 7 [17%]). Injuries involving a knee-dominant pattern with valgus were identified in 64% of cases. Injuries were evenly distributed between the first (53%) and second (47%) halves of a game. Half (50%) occurred within the first 10 minutes of effective playing time, and the most frequent months of injury were October and November (44%; early season). Nearly half (46%) of the injuries occurred in small forwards, with 59% of injuries occurring in zone 5. Neurocognitive errors were seen in 56% of injuries, while 92% of defensive injuries showed signs of neurocognitive errors.

CONCLUSION

ACL injuries in professional female basketball players were caused by indirect contact or noncontact, involving offensive and defensive cuts as well as landing from a jump. Biomechanical analysis confirmed a multiplanar mechanism with a knee-dominant pattern and valgus. Most injuries occurred early in the season and within the first 20 effective minutes played (89%), making accumulated fatigue an unlikely risk factor for ACL injuries in basketball players.

Young male players exhibit higher eccentric hamstring muscle fatigue than females and older males after a basketball match participation

OBJECTIVES

Investigating hamstring eccentric strength before and after a basketball match.

DESIGN

Cohort observational study.

SETTING

Playing facilities of local basketball teams on official championship matches.

PARTICIPANTS

Forty-four healthy male and female 14-25-year-old basketball athletes.

MAIN OUTCOME MEASURES

Hamstring mean, absolute peak torque, and total work were measured during the execution of the Nordic hamstring exercise before and after a match. Anterior knee laxity was also measured.

RESULTS

The results showed non-significant intersex pre- vs. post-match changes for all measured parameters. The 14-19-year-old male players showed a significantly lower post-match mean hamstring peak torque than their 20-25-year-old peers (p = 0.013). Hamstring strength correlated with age in males with the younger players significantly weaker post-match than the older athletes. Younger vs. older males experienced a mean eccentric hamstring peak torque decrease of 16.4 ± 38.18 Nm (-5.6 %) vs. an increase of 27.55 ± 41.87 Nm (11.8 % - Spearman R = 0.408), an absolute eccentric hamstring peak torque reduction of 13.32 ± 35.45 Nm (-4 %) vs. an improvement of 31.5 ± 43.83 Nm (11.6 % - R = 0.434), and a hamstring work decline of 1474.5 ± 1370.83 J (-19.2 %) vs. an increment of 560.32 ± 1584.28 J (13.2 % - R = 0.627) respectively.

CONCLUSIONS

Younger male basketball players were more fatigued post-match compared to their older same-sex peers.

Impact of anterior cruciate ligament tears on player efficiency ratings and salary in National Basketball Association over the past 20 years: a retrospective case control study

OBJECTIVES

Players in the National Basketball Association (NBA) are at high risk for ACL tears which are detrimental to their career due to the months of rehabilitation. The authors hypothesize that after anterior crucial ligament (ACL) injury, older players will be less likely to return to the NBA, players that do return will have a lower performance efficiency rating (PER), and the decrease in PER will be associated with a lower salary.

METHODS

This case-control study utilized the publicly available database maintained by the NBA, professional basketball players from 2002 to 2022 who suffered an ACL tear were identified. Controls, without ACL tears, were matched by age, BMI, position, race, and average minutes played before the injury date to uninjured controls. Return to NBA, pre-injury and post-return player efficiency ratings (PER), and salary change after injury were analyzed by multivariate analyses.

RESULTS

A total of 67 players suffered an ACL tear. Fifty-six (83.6%) players returned to the NBA at some point after their injury, while 11 (16.4%) did not. Multivariate logistic regression showed that older age and the presence of multi-ligament injury predicted retiring from the NBA (ß = 1.4 and 10.7). Older age and greater minutes played before surgery to be the only significant predictors of decreased PER after return to the NBA (ß = -0.5 and -0.2). Players with a multiyear contract and with improvements in PER after injury tended to have greater salary increases (ß = 6.5 and 0.7). All p < 0.05. PER in players with ACL tears decreased by about 3 points (13.1 to 9.9) compared to controls without ACL tears (13.2 to 12.9).

CONCLUSION

Older age and multiligament injuries are associated with retiring for the NBA; older and increased minutes played are associated with a decreased PER upon return; and, PER decreases are associated with decreased salary. Players with ACL tears, even when case-control matched, showed decreased PER upon return. These results can be attributed to age-related changes in athleticism and health.

Single-Leg Countermovement Jump Compensation Assessment: Content Validity of a Checklist

Jump actions are common in several sports, and their performance is related to a myriad of biomechanical and physiological factors, with links to athletic performance and imbalances. Currently, a valid, field-based, easy-to-use tool to assess the quality of an explosive jump movement, similar to the required sports movements, is unavailable. Thus, the present study aimed to design and validate a field-based, easy-to-use tool that can be used to assess the quality of movement during an explosive single-leg countermovement jump (SL-CMJ). Ten experts participated in the content validation process for the checklist, including checking item relevance, definition accuracy, and scoring adequacy. Content validity was measured using the Aikens V format. The checklist included the items "Foot orientation," "Knee valgus/varus," "Internal/external hip flexed orientation," "Pelvis tilt," "Thorax tilt," "Thorax rotation," "Foot pronation/supination," "Asymmetrical hip," and "Lumbo-pelvic association". The items achieved a 0.60-0.99 in relevance, 0.70-1.00 in definition accuracy, and 0.80-0.83 in scoring adequacies in the Aikens V proof. The results from the context validation process suggest that the tool may be appropriate to assess athletes' quality of explosive movement. Furthermore, the results derived from such assessments may help to design better and safer training interventions.

A systematic review and network meta-analysis on the effectiveness of exercise-based interventions for reducing the injury incidence in youth team-sport players. Part 2: an analysis by movement patterns

The objectives of this network meta-analysis were: (a) to estimate and compare the pooled effects of some injury prevention programs (IPPs) whose exercise-based components were categorized using a movement pattern-specific taxonomy on reducing overall and some specific body regions (lower extremity, thigh, knee, and ankle) injury incidences in youth team sport athletes and (b) to explore the individual effects of these components on the injury incidence rates (IIRs) previously mentioned. Searches were performed in PubMed, Web of Science, SPORTDiscus, and Cochrane Library. Eligible criteria were: exercise-based interventions comprised of exercises involving athletic motor skill competencies and evaluated against a control group, overall IIRs were reported, and youth (≤19 years old) team sport players. For the current analysis, a taxonomy based on movement patterns was employed for exercise component identification (upper body pushing and pulling; lower body concentric and eccentric; core; mechanics; acceleration; and lower body stability). Pooled effects were calculated by frequentist random effects pairwise and network meta-analyses. Nineteen studies were included. Most of the IPPs exhibit risk reduction when compared to their control groups on overall, lower extremity, and ankle injuries. Interventions comprised of lower body concentric and eccentric, core, mechanics, and lower body stability exercises were the most effective measures for reducing these injuries. None of the IPPs demonstrated to be effective for reducing thigh injuries, and contradictory results were found for knee injuries. Individual analysis at component level revealed that the lower body (bilateral and unilateral, concentric, and eccentric) component was the only one associated with a significant reduction on overall injuries. Indirect evidence suggests that interventions incorporating lower body concentric and eccentric, core, mechanics, and lower body stability exercises might be the most effective for reducing overall, lower extremity, and ankle injuries in youth team sports.

ACL injury management: a comprehensive review of novel biotherapeutics

The anterior cruciate ligament (ACL) is integral to the stability of the knee joint, serving to limit anterior tibial translation and regulate rotational movements. ACL injuries are among the most common and debilitating forms of knee trauma, often resulting in joint effusion, muscular atrophy, and diminished athletic capabilities. Despite the established efficacy of ACL reconstruction as the standard treatment, it is not uniformly successful. Consequently, there is a growing interest in novel biotherapeutic interventions as potential alternatives. This comprehensive review examines the latest advancements in ACL biotherapy, encompassing the application of hyaluronic acid, self-assembled short peptides, growth factors, stem cell therapy, gene therapy, platelet-rich plasma therapy, bone marrow aspirate concentrate cells, extracorporeal shock wave, electrical stimulation and cross bracing protocol. The collective aim of these innovative treatments is to facilitate the restoration of the ACL's native biological and biomechanical integrity, with the ultimate goal of enhancing clinical outcomes and the functional recovery of affected individuals.

Increased Visual Attentional Demands Alter Lower Extremity Sidestep Cutting Kinematics in Male Basketball Players

Background

In basketball, changing direction is one of the primary mechanisms of anterior cruciate ligament (ACL) injury, often occurring within complex game situations with high cognitive demands. It is unknown how visual attention affects sidestep cutting kinematics during the entire energy absorption phase of the cut in an ecologically valid environment.

Purpose

The purpose of this research was to study the effect of added cognitive load, in the form of increased visual attentional demands, on sidestep cutting kinematics during the energy absorption phase of the cut in an ecologically valid environment.

Study Design

Crossover Study.

Methods

Fifteen male basketball players (aged 22.1 ± 2.3) performed ten sidestep cutting movements without (BASE) and with (VIS) a visual attention dual task. 3D kinematics of the hip, knee and ankle were recorded utilizing Xsens IMU motion capture. Temporal kinematics were analyzed using Statistical Parametric Mapping. Discrete time point kinematics were additionally analyzed at initial contact (IC) and at peak knee flexion utilizing paired t-tests. Effect sizes were calculated.

Results

Hip flexion was significantly reduced in the VIS condition compared to the BASE condition (p<0.01), including at IC (VIS 35.0° ± 7.2°, BASE 40.7° ± 4.9°, p=0.02, d=0.92) and peak (VIS 37.8° ± 9.7°, BASE 45.5° ± 6.9°, p=0.001, d=0.90). Knee flexion was significantly reduced in the VIS condition, in comparison to the BASE condition (p<0.01), at peak (VIS 59.9° ± 7.5°, BASE 64.1° ± 7.4°, p=0.001, d=0.55).

Conclusion

The addition of visual attention during sidestep cutting altered lower limb kinematics, which may increase ACL injury risk. It is suggested that ACL injury risk screening and prevention should include sidestep cutting with visual attentional demands, in order to mimic the cognitive demands of the sports environment.

Level of Evidence

3.

Direct contact and very rapid valgus distortion characterise the injury mechanism of anterior cruciate ligament ruptures in judo

PURPOSE

To analyse anterior cruciate ligament (ACL) rupture (ACLR) injury mechanisms in competitive judo using systematic video analysis, focusing on contact situations and biomechanics.

METHODS

Seventeen videos of judo competitions wherein athletes developed ACLRs were included and retrospectively evaluated by five analysts. In all videos, the moment of initial contact and the index frame were defined. The judo techniques leading to the injury; the occurrence of direct contact, indirect contact or noncontact mechanisms; the time interval between the initial contact and index frame; the positions of the hip, knee and foot in relation to the initial contact and index frame; and the balance status during the initial contact and index frame were recorded.

RESULTS

Eleven (65%) of ACLRs in judo involved direct contact. The mean time interval between initial contact and index frame was 15 ± 22 ms. Thirteen (77%) athletes were not balanced at initial contact. In the index frame, the hip was abducted in all cases and in combination with internal rotation in 12 (71%) cases. From initial contact to index frame, hip flexion increased in all cases; at index frame, the knee joint was internally rotated relative to the trunk in 12 (71%) cases, and the knee flexion angles increased from the initial contact. In the index frame, the foot was externally rotated relative to the knee in 12 (71%) cases, and severe valgus development of the knee with valgus collapse was observed in 14 (82%) cases.

CONCLUSIONS

A direct attack on the knee was the most common injury mechanism observed. Valgus distortion appears to be the most important component of the mechanism of injury. With this knowledge, 'modified defence reactions' for specific judo techniques can be developed to reduce the injury risk.

LEVEL OF EVIDENCE

Level IV.

Decreased sagittal slope of the medial tibial spine and deep concavity of the lateral tibial spine are risk factors for noncontact anterior cruciate ligament injury

PURPOSE

This study aimed to assess the relationship between the geometric features of tibial eminence and susceptibility to noncontact anterior cruciate ligament (ACL) injuries.

METHODS

Patients with unilateral noncontact knee injuries between 2015 and 2021 were consecutively enroled in this study. Based on knee magnetic resonance imaging (MRI) and arthroscopic visualisation, patients were categorised into the case group (ACL rupture) and control group (ACL intact). Using MRI, the geometric features of tibial eminence were characterised by measuring the sagittal slopes, depth of concavity and coronal slopes of the inclined surfaces of the tibial spines. Univariate and multivariate logistic regressions were conducted to explore independent associations between quantified geometric indices of tibial eminence and the risk of noncontact ACL injuries.

RESULTS

This study included 187 cases and 199 controls. A decreased sagittal slope of the medial tibial spine (MTSSS) (combined group: odds ratio [OR]: 0.87 [0.82, 0.92], p < 0.001; females: OR: 0.88 [0.80, 0.98], p = 0.020; males: OR: 0.87 [0.81, 0.93], p < 0.001) and an increased depth of concavity in the lateral tibial spine (LTSD) (combined group: OR: 1.51 [1.24, 1.85], p < 0.001; females: OR: 1.65 [1.12, 2.43], p = 0.012; males: OR: 1.44 [1.11, 1.89], p = 0.007) were independent risk factors for noncontact ACL injuries. Moreover, a steeper coronal slope of the inclined surface of the medial tibial spine was a significant predictor of noncontact ACL injuries for males (MTSCS: OR: 1.04 [1.01, 1.08], p = 0.015) but not for females.

CONCLUSION

Geometric features of tibial eminence, particularly a decreased MTSSS and an increased LTSD, were identified as independent risk factors for noncontact ACL injuries. These findings will help clinicians identify individuals at high risk of ACL injury and facilitate the development of targeted prevention strategies.

LEVEL OF EVIDENCE

Level III.

Team Approach: Neuromuscular Training for Primary and Secondary Prevention of Anterior Cruciate Ligament Injury

Neuromuscular training is a method of performance optimization-typically combining plyometrics, balancing training, agility, and dynamic stabilization-predicated on improving the efficiency of fundamental movement patterns. Neuromuscular training has consistently been shown to reduce the risk of anterior cruciate ligament injury, particularly for athletes engaged in activities associated with noncontact knee injuries (i.e., women's soccer). Successful implementation of neuromuscular training programs requires input from coaches, physical therapists, athletic trainers, and physicians to generate efficacious programs with high rates of adherence.