Simple decision rules can reduce reinjury risk by 84% after ACL reconstruction: the Delaware-Oslo ACL cohort study

Editorial Commentary: Anterior Cruciate Ligament Patients Must Be Provided With Both Motivation and Tools to Continue Physical Therapy, Supervised or Independently, Beyond the Early Recovery Phase

Given the current American health insurance environment, many patients do not access physical therapy in the mid and later stages of recovery from anterior cruciate ligament (ACL) reconstruction. This trend is well established in the literature and seems very unlikely to change in the future. While highly competitive athletes generally have year-round access to therapists and trainers to guide them through months of recovery, most patients recovering from ACL reconstruction are recreational athletes with jobs, families, and varying levels of insurance coverage. This trend is well established in the literature, and recent research shows a substantial drop-off in physical therapy participation after 3 months. There are many potential reasons for the decreased utilization, including limitations in physical therapy visits covered by insurance, patient improvement to levels of near-normal motion and gait, and participation fatigue. Thankfully, this may be one of the instances where the latest technologies such as artificial intelligence can be beneficial, and many studies have shown advantages of telehealth in the field of physical therapy. Most of all, surgeons must act as educators and provide our post-ACL reconstruction patients with motivation and tools to continue physical therapy, if not supervised, then independently, beyond the early recovery phase.

Joint Effusion at 3 Months After Anterior Cruciate Ligament Reconstruction: Its Risk Factors and Association With Subsequent Muscle Strength and Graft Remodeling

Background

Joint effusion at 3 months after anterior cruciate ligament (ACL) reconstruction is a risk factor for ACL reinjury. However, factors associated with joint effusion at 3 months postoperatively and the effect of joint effusion on subsequent quadriceps muscle strength and graft remodeling remain unknown.

Purposes

To identify factors associated with joint effusion and investigate the association between joint effusion and quadriceps muscle strength and graft remodeling in the postoperative period.

Study Design

Case-control study; Level of evidence, 3.

Methods

In this retrospective multicenter study, the medical records of patients who underwent single-bundle ACL reconstruction between 2015 and 2021 were reviewed. The study included the data of 174 patients (mean age, 23.5 ± 10.6 years). Demographic data, including sex, age at surgery, time from injury to surgery in months, body mass index, preinjury Tegner activity score, presence of meniscus, and chondral injuries, were collected. Magnetic resonance imaging was performed 3 months postoperatively. Joint effusion was defined as grade 3 (range of grades, 0-3) according to the ACL Osteoarthritis Score. Isokinetic strength testing was performed at 60 deg/s, while the limb symmetry index (LSI) of quadriceps strength was evaluated at 6 months postoperatively. Moreover, graft remodeling was evaluated using magnetic resonance imaging-derived signal intensity ratio (SIR) measures at 1 year postoperatively. The authors used multivariate logistic and linear regression analyses to identify the factors influencing joint effusion at 3 months and those associated with postoperative quadriceps strength LSI and SIR values, respectively.

Results

Greater preinjury Tegner activity scores (odds ratio, 1.59; 95% CI, 1.08 to 2.34; P = .02) increased the odds of joint effusion at 3 months postoperatively. Multivariable linear regression analysis revealed that joint effusion (β = -23.8; 95% CI, -36.0 to -11.7; P < .001) was an independent factor associated with LSI of the quadriceps. Furthermore, joint effusion (β = 1.33; 95% CI, 0.53 to 2.14; P = .001) was associated with a higher SIR value of the reconstructed graft.

Conclusion

The preinjury Tegner activity score was a factor associated with joint effusion at 3 months postoperatively, and joint effusion was associated with subsequent muscle weakness and delayed graft remodeling.

Neurocognitive and Neuromuscular Rehabilitation Techniques after ACL injury - Part 2: Maximizing Performance in the Advanced Return to Sport Phase

Background

Anterior cruciate ligament (ACL) injury and reinjury rates are on the rise, despite improved surgical techniques and prevention programs. ACL injuries also lead to a variety of neuroplastic and neuromuscular alterations. Emerging research highlights the importance of addressing neurocognitive deficits that can persist after injury including altered proprioception, impaired motor control, muscle recruitment and heightened reliance on visual feedback. This suggests a shift from subconscious movement, to movements that require increased volitional control, which may contribute to increased risk of re-injury and thus impede return to sport.

Clinical Question

Given the neurophysiological changes associated with anterior cruciate ligament (ACL) injury that persistent into the late stages of rehabilitation, does the integration of neurocognitive training into mid to late stage rehabilitation protocols improve functional outcomes and reduce the risk of re-injury following ACL reconstruction (ACLR) in athletes?

Purpose

The purpose of Part 2 of this clinical commentary is to offer strategies to implement neurocognitive training elements into the traditional ACLR rehabilitation (in weeks 9+) and review updated testing metrics that may better discern an athletes readiness to return to competition. A comprehensive rehabilitation framework incorporating both physical and neurocognitive components is proposed, aiming to improve both long-term outcomes and return to sport testing, as well as diminishing re-injury risk.

Conclusion

Updates to the traditional rehabilitation approach post ACLR, that include increased emphasis on neuroplastic, cognitive, and visual-motor capabilities exist. These help prepare athletes for the unpredictable and chaotic nature of the sporting environment and may facilitate a more effective return to sport for athletes, potentially mitigating the risk of re-injury.

Level of Evidence

5.

A Novel Method to Measure Dual-Task Capacity in Young Football Players: A Preliminary Study

CONTEXT

When deciding to return to sport, in the literature, evaluations based on physical abilities have usually been used. However, in the current literature, we have been urged to use more than physical performance evaluations. Classical dual-task testing methods do not simulate in-game loads and cannot sufficiently measure football players' dual-task capacity.

OBJECTIVE

To create a dual-task test that would simulate football players' in-game situations and measure their capacity.

DESIGN

Cross-sectional study.

SETTING

Football pitch.

PATIENTS OR OTHER PARTICIPANTS

Twenty-two football players (age = 17.37 ± 0.52 years) who played in a professional club (U19, elite league) were recruited for our study.

INTERVENTION(S)

A novel dual-task test with questions containing scenarios from a football game to cognitively load players while they are performing a modified t test.

MAIN OUTCOME MEASURE(S)

After the warmup period, participants attended 4 tests in random order: juggling (foot), speed dribbling, long passing, and novel dual-task tests.

RESULTS

No significant relationship was found between physical performance parameters and dual-task parameters (all P > .05). A significant increase was found in the completion time of the modified t test when performed under the dual-task condition (Z = -7.568, P < .001). The increase in completion time was 2.14 ± 1.29 seconds. This duration difference was calculated as 22.79% ± 14.58%, as dual-task cost.

CONCLUSIONS

Our test provides a new method to measure athletes' dual-task capacity, which is not related to physical performance and cannot be measured with current tests. This test also showed players with lower dual-task ability could not keep up their performance under dual-task conditions, such as passing a ball to a teammate when being pressed by an opponent. Players with good dual-task ability could maintain their performance (were affected only up to 10%); players with poor dual-task ability could not maintain their performance and were affected by up to 50% (with a mean of 22.79%).

A simple 2D multibody model to better quantify the movement quality of anterior cruciate ligament patients during single leg hop

Patients with anterior cruciate ligament reconstruction frequently present asymmetries in the sagittal plane dynamics when performing single leg jumps but their assessment is inaccessible to health-care professionals as it requires a complex and expensive system. With the development of deep learning methods for human pose detection, kinematics can be quantified based on a video and this study aimed to investigate whether a relatively simple 2D multibody model could predict relevant dynamic biomarkers based on the kinematics using inverse dynamics. Six participants performed ten vertical and forward single leg hops while the kinematics and the ground reaction force "GRF" were captured using an optoelectronic system coupled with a force platform. The participants are modelled by a seven rigid bodies system and the sagittal plane kinematics was used as model input. Model outputs were compared to values measured by the force platform using intraclass correlation coefficients for seven outcomes: the peak vertical and antero-posterior GRFs and the impulses during the propulsion and landing phases and the loading ratio. The model reliability is either good or excellent for all outcomes (0,845 ≤ ICC ≤ 0.987). The study results are promising for deploying the developed model following a kinematics analysis based on a video. This could enable clinicians to assess their patients' jumps more effectively using video recordings made with widely available smartphones, even outside the laboratory.

Associations Between Race and Socioeconomic Status, Lower Extremity Strength, and Patient-Reported Outcomes Following Anterior Cruciate Ligament Reconstruction

CONTEXT

There are significant disparities in access to health care, but there are limited data about the impact of race and socioeconomic status on postoperative outcomes following anterior cruciate ligament reconstruction (ACLR) surgery.

OBJECTIVE

To identify associations between the Area Deprivation Index (ADI), strength measures, and patient-reported outcomes following ACLR and examine differences in outcomes between race, sex, and socioeconomic status.

DESIGN

Case-control study in a single hospital setting.

SETTING

Database secondary analysis.

PATIENTS OR OTHER PARTICIPANTS

Data were collected from 340 patients who underwent primary, isolated, unilateral ACLR.

MAIN OUTCOME MEASURE(S)

Strength measures and patient-reported outcomes were obtained at patients' postoperative assessments at approximately 6 months postsurgery. Area Deprivation Index values were calculated on each patient's census tract, as determined through medical records review. Correlations were conducted to determine the relationship between the ADI and Knee Injury and Osteoarthritis Outcome Score measures, International Knee Documentation Committee, and limb symmetry on strength measurements. The racial composition of the sample was heavily skewed and was excluded from statistical analyses.

RESULTS

The ADI was weakly correlated with International Knee Documentation Committee (ρ = 0.11, P = .04) outcomes, with more disadvantaged patients reporting better quality of life and knee function. The ADI was not correlated with other outcomes of interest. The median ADI value of the sample was 32 (range, 1-86 [interquartile range, 19-47]).

CONCLUSIONS

Our study revealed a weak correlation between higher levels of socioeconomic disadvantage as measured by the ADI and improved subjective assessment of knee function and quality of life as measured by International Knee Documentation Committee. These findings are contrary to what other studies on this subject have found and highlight the importance of further research into the impact of socioeconomic status and other social determinants of health on post-ACLR outcomes.

Higher isokinetic quadriceps peak force is associated with a patient-acceptable symptom-state 1 and 3 years after ACL reconstruction

PURPOSE

The main purpose was to determine cut-off values for absolute (QNm/kg) and relative (QLSI) isokinetic knee extensor (KE) strength for achieving a patient-acceptable symptom state (PASS) in the Knee injury and Osteoarthritis Outcome Score (KOOS) subscales and for different age groups to determine the association between QNm/kg and QLSI and PASS, at 1 and 3 years after an anterior cruciate ligament reconstruction (ACLR).

METHODS

PASS was defined as reaching cut-off values for all KOOS subscales. Data from follow-ups were extracted from a rehabilitation registry. Male and female patients were divided into two age groups based on their age at primary ACLR: 16-24 years and 25-65 years. Odds Ratios between the QNm/kg and QLSI cut-off values and achieving PASS were calculated. Receiver Operating Characteristic curves were constructed to determine the individual predictive capacity for achieving PASS of QNm/kg and of QLSI using the area under the curve (AUC).

RESULTS

Results from 755 and 145 patients (females = 51% and 52%; preinjury Tegner Activity level ≥6 = 82% and 74%) were used in the 1- and 3-year follow-up analyses. Reaching the cut-off values for the QNm/kg, ranging between ≥2.1 and ≥2.7, entailed between 2.09 and 5.12 times the odds of achieving PASS, across all groups at the 1-year follow-up. At the 3-year follow-up, the cut-off values of ≥3.4 and ≥2.6QNm/kg were associated with patients achieving PASS with acceptable accuracy (AUC = 0.700-0.780) in 16-41 year-old males and females.

CONCLUSION

At 1 year after ACLR, patients of both sexes and age groups reaching cut-off values for absolute KE strength had two to five times the odds, that were clinically relevant, to achieve PASS. Acceptable discriminative capacity was found for the absolute KE strength among male and female patients 16-24 years old, at 3 years after ACLR.

LEVEL OF EVIDENCE

Level III.

Limited Use of Supervised Physical Rehabilitation Beyond 3 Months After Arthroscopic Anterior Cruciate Ligament Reconstruction With Greater Use in Female and Younger Patients

PURPOSE

To characterize the initiation and use of supervised physical rehabilitation after arthroscopic anterior cruciate ligament reconstruction (ACLR), including overall duration of rehabilitation and number of rehabilitation visits, and to describe demographic and clinical predictors of rehabilitation initiation and use characteristics.

METHODS

Patients aged 14 to 64 years in the United States who underwent ACLR from 2017 to 2020 were identified using the Merative MarketScan Database. For patients initiating rehabilitation within 45 days postoperatively, the overall duration and number of visits within 1 year after surgery were determined. Visits were categorized into rehabilitation phases, with visits 0-90 days postoperatively categorized as phase I, 91-180 days as phase II, 181-270 days as phase III, and 271-365 days as phase IV. Multivariable regression models identified predictors of rehabilitation initiation, duration in days, and number of visits.

RESULTS

Of 20,097 patients who underwent ACLR, 88.1% (n = 17,704) initiated postoperative rehabilitation, receiving phase I services. Additionally, 55.0% (n = 11,053) received phase II services, 17.0% (n = 3417) phase III services, and 3.9% (n = 779) phase IV services. The median duration was 104 days (interquartile range 63-157), and the median number of visits was 21 (interquartile range 12-32). Multiple significant predictors of rehabilitation initiation, duration, and number of visits were found.

CONCLUSIONS

Although most patients use supervised physical rehabilitation after ACLR, only 55% receive rehabilitation beyond 3 months and only 17% beyond 6 months after surgery. There are several significant drivers of rehabilitation initiation, overall duration, and number of visits. Female and younger patients have greater use of rehabilitation, and notable regional differences suggest an opportunity to improve standardization of care.

LEVEL OF EVIDENCE

Level III, retrospective descriptive study.

Improved Quadriceps Torque Production With Optimized Biofeedback in Patients After Anterior Cruciate Ligament Reconstruction

Hogg, JA, Barger, NB, Bruce, JR, White, CC, Myer, GD, and Diekfuss, JA. Improved quadriceps torque production with optimized biofeedback in patients after anterior cruciate ligament reconstruction. J Strength Cond Res XX(X): 000–000, 2024—Optimizing performance through intrinsic motivation and attention for learning: prevention rehabilitation exercise play (OPTIMAL PREP) training strategies incorporate motor learning principles to enhance movement acquisition and retention. We aimed to use OPTIMAL PREP biofeedback to evaluate its potential to improve quadriceps and hamstring torque production in patients with anterior cruciate ligament reconstruction (ACL-R). Thirteen subjects 23 ± 19 months post ACL-R completed 5 concentric quadriceps/hamstrings repetitions on an isokinetic dynamometer for each limb and counterbalanced condition at 60°·s−1. For the control condition, subjects were instructed to perform the exercise “as hard and fast as possible.” For the OPTIMAL PREP condition, subjects were additionally told that “Research shows that if you focus on moving the line on the screen (external focus) you will exhibit greater quadriceps output (enhanced expectancies)” and were given the choice of graphical representation for the biofeedback (autonomy support). Quadriceps and hamstrings peak torque, rate of force development, and torque-angle waveforms were analyzed with 2 × 2 RMANOVAs (a priori >0.06). The ACL-R limb demonstrated increased quadriceps peak torque in the OPTIMAL PREP condition than in the control condition ( = 0.13, interaction p = 0.21, pairwise Cohen's d = 0.63). Anterior cruciate ligament reconstruction limb quadriceps deficits remained near terminal extension (14–45°; peak Cohen's d = 0.57, p < 0.001). For hamstrings peak torque, we observed moderate effects for condition (OPTIMAL PREP greater; = 0.10, p = 0.29) and limb (uninvolved greater; = 0.13, p = 0.22). Easily implementable OPTIMAL PREP training strategies improved ACL-R limb quadriceps torque production, resulting in between-limb parity. However, asymmetries still existed near terminal extension.

From Fear to Resilience: A Scoping Review of Psychological Components in Anterior Cruciate Ligament Rehabilitation

CONTEXT

Anterior cruciate ligament (ACL) injuries, prevalent in athletic contexts have profound physical and psychological impacts. Despite extensive research on the physiological aspects of ACL recovery, the psychological dimensions of this process have gained increased attention. This scoping review delves into the intricate landscape of psychological factors influencing ACL rehabilitation.

DESIGN

Scoping review.

METHODS

A literature search across multiple databases was conducted to identify relevant published studies that provide insight into the psychological aspects of ACL recovery. This search spanned various study designs, enabling a nuanced understanding of the psychological intricacies surrounding ACL recovery. Overall, a total of 1830 unique articles were screened, of which 66 were included in this review. Our findings are further contextualized through alignment with insights from prior reviews on similar themes. Through a comprehensive analysis of diverse literature, we explore 3 key themes: psychological challenges, current rehabilitation programs, and the integration of psychological support.

RESULTS

Psychological challenges emerged as a pervasive aspect of ACL rehabilitation, encompassing fear, anxiety, motivation, and depression. The nuanced emotional responses, particularly the fear of reinjury, impact treatment adherence and overall well-being. Contemporary rehabilitation programs revealed inconsistencies in incorporating psychological support, emphasizing the need for standardized, multidisciplinary approaches. The alignment with prior reviews in the literature reinforced the importance of psychological traits, such as knee self-efficacy, in predicting positive outcomes.

CONCLUSION

This scoping review provides a comprehensive overview of psychological factors within ACL rehabilitation, highlighting the importance of tailored interventions and standardized approaches. The integration of multidisciplinary expertise emerges as crucial for optimizing patient outcomes. Our findings not only contribute to a nuanced understanding of psychological nuances in ACL rehabilitation but also offer valuable implications for clinical practice and policy development.

Advanced Neuromuscular Training Differentially Changes Performance on Visuomotor Reaction Tests and Single-leg Hop Tests in Patients with ACL Reconstruction

Background

Advanced neuromuscular training prepares patients with anterior cruciate ligament reconstruction (ACLR) for sport participation. Return-to-sport testing often includes single-leg hop tests, yet combining motor and cognitive tasks (i.e., dual-task) might reveal neurocognitive reliance.

Purpose/Hypothesis

This study examined changes in performance on visuomotor reactions tests and single-leg hop tests following advanced neuromuscular training in patients with ACLR. The hypothesis was that performance would improve less on reaction tests than on single-leg hop tests.

Study Design

Quasi experimental, Pretest-Posttest.

Methods

Twenty-five patients with ACLR (11 males) completed 10 sessions of advanced neuromuscular training and pre-and post-training testing. Reaction tests outcomes were from a platform and visual display. The double-leg reaction test involved touching target dots with either leg for 20 seconds; correct touches and errors were recorded. The single-leg reaction test involved hopping on the test leg to 10 target dots; hop time and errors were recorded. Single-leg hop tests included forward, triple, crossover triple, and timed hop; limb symmetry index was recorded. Effect sizes were calculated for corrected touches on the double-leg reaction test, surgical side hop time on the single-leg reaction test, and surgical side hop distance or time on single-leg hop tests.

Results

Correct touches on the double-leg reaction test significantly increased from pre- to post-training (20.4 +/- 4.3 vs. 23.9 +/- 2.8, p<0.001). Hop time on the single-leg reaction test significantly decreased from pre- to post-training (Surgical leg 13.2 vs. 12.3 seconds, non-surgical leg 13.0 vs. 12.1 seconds, p=0.003). Mean errors did not significantly change on either reaction test (p> 0.05). Cohens d effect sizes in descending order was single-leg hop tests (d=0.9 to 1.3), double-leg reaction test (d=0.9), and single-leg reaction test (d=0.5).

Conclusion

Motor performance improved after advanced neuromuscular training, but the effect size was less on visuomotor reaction tests than single-leg hop tests. The results suggest persistence of neurocognitive reliance after ACLR and a need for more dual-task challenges in training.

Level of Evidence

3.

Effective Prevention and Rehabilitation Strategies to Mitigate Non-Contact Anterior Cruciate Ligament Injuries: A Narrative Review

Non-contact anterior cruciate ligament injuries (NC-ACLs) represent a significant concern in sports medicine, particularly among athletes and physically active individuals. These injuries not only result in immediate functional impairment but also predispose individuals to long-term issues such as recurrent instability and early-onset osteoarthritis. This narrative review examines the biomechanical, neuromuscular, and environmental factors that contribute to the high incidence of NC-ACLs and evaluates the effectiveness of current prevention and rehabilitation strategies. The review identifies key risk factors, including improper landing mechanics, deficits in neuromuscular control, and muscle imbalances, which are pivotal in the etiology of NC-ACLs. Prevention programs that incorporate plyometric exercises, strength training, and neuromuscular education have shown efficacy in reducing injury rates. Rehabilitation protocols that emphasize a gradual return to sport, focusing on pain management, restoration of range of motion, and progressive strengthening, are critical for successful recovery and prevention of re-injury. The evidence suggests that an integrated approach, combining prevention and rehabilitation strategies tailored to the individual, is essential for minimizing NC-ACL risk and improving outcomes in affected populations.

Which technique provides more benefits in return to sports and clinical outcomes after anterior cruciate ligament reconstruction: Double-bundle or single-bundle? A randomized controlled study

BACKGROUND

The achievement of an optimal return to sport (RTS) has remained a key goal after sports-related injuries, with the ongoing debate on the effectiveness of different surgical approaches for anterior cruciate ligament (ACL) rupture. This study aims to assess clinical outcomes and RTS across various surgical methods, such as anatomical single-bundle reconstruction (ASBR), central-axial single-bundle reconstruction (CASBR), and double-bundle reconstruction (DBR).

METHODS

A randomized clinical trial was conducted, comprising 191 patients who underwent ACL rupture. These patients were divided into three groups based on the ACL reconstruction techniques they received (ASBR, CASBR, DBR). Over the 2-year follow-up period, the study assessed RTS through four single-hop tests, isokinetic extension tests, and limb asymmetry indices. Postoperative graft status was determined using the signal-to-noise quotient (SNQ), while knee function was evaluated using the International Knee Documentation Committee 2000 (IKDC-2000) score, Lysholm score, Tegner score, and degree of knee laxity. A binary logistic regression model was developed to forecast the factors influencing ideal RTS.

RESULTS

DBR (67.63%) and CASBR (58.00%) exhibited higher RTS passing rates compared to ASBR (30.39%; χ2 = 19.57, P <0.05). Quadriceps strength symmetry in the lower limbs was identified as the key determinant of RTS (χ2 = 17.08, P <0.05). The RTS rate was influenced by SNQs of the graft's tibial site (odds ratio: 0.544) and quadriceps strength of the reconstructed knee joint at 60°/s (odds ratio: 6.346). Notably, the DBR group showed enhanced knee stability, evidenced by superior results in the Lachman test (χ2 = 13.49, P <0.01), objective IKDC-2000 (χ2 = 27.02, P = 0.002), and anterior instability test (χ2 = 9.46, P <0.01). Furthermore, DBR demonstrated superior clinical outcomes based on the Lysholm score (DBR: 89.57 ± 7.72, CASBR: 83.00 ± 12.71, ASBR: 83.21 ± 11.95; F = 10.452, P <0.01) and IKDC-2000 score (DBR: 90.95 ± 7.00, CASBR: 84.64 ± 12.68, ASBR: 83.63 ± 11.41; F = 11.78, P <0.01).

CONCLUSION

For patients with ACL rupture, more ideal RTS rate and clinical outcomes were shown in the DBR group than in the ASBR and CASBR groups. Autograft status and quadriceps strength are postively related to RTS.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT05400460).

An 8-week physiotherapist-led return to sport group program after anterior cruciate ligament reconstruction improves measures of physical and psychological function: A case series

BACKGROUND

Low return to competitive sport, high reinjury rates and long-term functional impairment of anterior cruciate ligament reconstruction (ACLR) present significant challenges for patients. A program that facilitates a safe return to sport (RTS) following ACLR could potentially improve outcomes.

STUDY DESIGN

Case Series.

METHODS

Sixty participants (median 20-years-old (13-36), 43 males, 18 females, median 7.5 months (4-25) post-ACLR) completed an eight-week exercise program. A battery of physical tests and patient-reported outcome measures were assessed pre and post-program. The number of participants passing RTS criteria was evaluated, and RTS rates were determined. The correlation between the ACL-RSI and measures of physical function was explored.

RESULTS

Improvements in all isometric strength, hop tests, running T-test, and patient reported outcome measures were seen post-program. Five (8%) participants successfully passed all RTS criteria and eighty-five percent of participants returned to their previous level of sport. The ACL-RSI and the IKDC showed correlation across all time points (pre rs = 0.49; post rs = 0.40; change r = 0.40).

CONCLUSIONS

Our study demonstrated improvements in all RTS criteria tests upon completing the 8-week rehabilitation program; however, few participants (8%) passed all RTS criteria. Psychological readiness is more closely related to patient-reported function than functional tests.

Neuroplastic alterations in common synaptic inputs and synergistic motor unit clusters controlling the vastii muscles of individuals with ACL reconstruction

This cross-sectional study aims to elucidate the neural mechanisms underlying the control of knee extension forces in individuals with anterior cruciate ligament reconstruction (ACLR). Eleven soccer players with ACLR and nine control players performed unilateral isometric knee extensions at 10% and 30% of their maximum voluntary force (MVF). Simultaneous recordings of high-density surface electromyography (HDEMG) and force output were conducted for each lower limb, and HDEMG data from the vastus lateralis (VL) and vastus medialis (VM) muscles were decomposed into individual motor unit spike trains. Force steadiness was estimated using the coefficient of variation of force. An intramuscular coherence analysis was adopted to estimate the common synaptic input (CSI) converging to each muscle. A factor analysis was applied to investigate the neural strategies underlying the control of synergistic motor neuron clusters, referred to as motor unit modes. Force steadiness was similar between lower limbs. However, motor neurons innervating the VL on the reconstructed side received a lower proportion of CSI at low-frequency bandwidths (<5 Hz) compared with the unaffected lower limbs (P < 0.01). Furthermore, the reconstructed side demonstrated a higher proportion of motor units associated with the neural input common to the synergistic muscle, as compared with the unaffected lower limbs (P < 0.01). These findings indicate that the VL muscle of reconstructed lower limbs contribute marginally to force steadiness and that a plastic rearrangement in synergistic clusters of motor units involved in the control of knee extension forces is evident following ACLR.NEW & NOTEWORTHY Chronic quadriceps dysfunction is common after anterior cruciate ligament reconstruction (ACLR). We investigated voluntary force control strategies by estimating common inputs to motor neurons innervating the vastii muscles. Our results showed attenuated common inputs to the vastus lateralis and plastic rearrangements in functional clusters of motor neurons modulating knee extension forces in the reconstructed limb. These findings suggest neuroplastic adjustments following ACLR that may occur to fine-tune the control of quadriceps forces.

Return to Play After an Anterior Cruciate Ligament Reconstruction in the Collegiate Athlete: A Systematic Review Evaluating Return to Play Proportions and Associated Factors

OBJECTIVE: To estimate anterior cruciate ligament reconstruction (ACLR) return-to-play (RTP) factors and proportions across all National Collegiate Athletics Association (NCAA) sports. DESIGN: Systematic review with prognosis and etiology components. LITERATURE SEARCH: Two independent reviewers searched PubMed, Cochrane Library, and Embase databases using terms related to RTP, ACLR, and NCAA for articles published up to June 30, 2023. STUDY SELECTION CRITERIA: Articles were included if RTP proportions or factors affecting RTP were reported and if the study population included NCAA collegiate athletes recovering from an ACLR. DATA SYNTHESIS: The proportion represents the total number of athletes who returned to play after ACLR over the total number of ACLR athletes from each cohort. The cumulative proportion represents the aggregated total from each included study. When eligibility information was available (ie, athletes in their final year of eligibility), RTP proportions were adjusted. The Newcastle-Ottawa Scale (NOS) was used to assess the study quality and scored by 2 raters. RESULTS: Nine studies were included. RTP criteria varied across the studies. Proportions of RTP ranged from 69% to 92%, with a cumulative RTP proportion after ACLR of 84% (628/745). The primary factors associated with the proportion of RTP were scholarship status, competitive eligibility remaining, depth chart position, and surgical graft type. CONCLUSIONS: The cumulative proportion of RTP was 84% and was associated with patient-specific and operative factors. Psychological and functional factors were not routinely reported, and rehabilitation protocols were unknown. Data were not explicitly available for any athletes outside of Division I. The criteria for RTP after ACLR varied. J Orthop Sports Phys Ther 2024;54(10):1-9. Epub 10 September 2024. https://doi.org/10.2519/jospt.2024.12483.

Quadriceps tendon size does not affect postoperative strength recovery following quadriceps tendon anterior cruciate ligament reconstruction

OBJECTIVE

The influence of quadriceps tendon (QT) size on postoperative quadriceps strength following QT anterior cruciate ligament reconstruction (ACLR) is unclear. Therefore, this study aimed to determine the relationship between QT morphology and postoperative quadriceps strength recovery following primary ACLR using a QT autograft.

METHODS

Patients who underwent primary ACLR using QT autograft from 2014 to 2022 followed by a postoperative isometric strength measurement between 5 and 8 months were retrospectively reviewed. Using preoperative magnetic resonance imaging findings, the anterior-posterior (A-P) thickness, medial-lateral (M-L) width, and cross-sectional area (CSA) of the QT were measured. Postoperative residual CSA of QT was estimated based on the graft-harvest diameter. The quadriceps index (QI) was also calculated, which was determined by dividing the maximum isometric quadriceps torque on the involved side by the maximum quadriceps torque on the uninvolved side. Associations between the QI and QT morphology were assessed. Furthermore, multivariable logistic regression analysis with the addition of sex as a covariate was performed with the addition of each individual measure of QT morphology to determine the association with a QI ​≥80%.

RESULTS

A total of 84 patients (mean age: 21.9 ​± ​7.3 years; 46 female) were included. Residual CSA showed a statistically significant positive correlation with the QI (r ​= ​0.221, p ​= ​0.043). There were no statistically significant correlations between QI and CSA, A-P thickness, or M-L width. Multivariable logistic analysis adjusting for sex demonstrated that each individual measure of QT morphology was not statistically significantly associated with a QI ​≥80%.

CONCLUSION

A statistically significant correlation between measures of preoperative QT size and postoperative quadriceps strength were not detected in patients undergoing primary QT autograft ACLR. A smaller residual QT CSA based on QT harvest diameter was weakly associated with decreased quadriceps strength 5-8 months postoperatively, but this association was not independent of sex. Future studies examining the impact of QT morphology on quadriceps strength at longer follow-up intervals are needed.

LEVEL OF EVIDENCE

IV.

Residual Performance and Biomechanical Asymmetries During Jumping Tasks in Female Athletes at 9 Months After Anterior Cruciate Ligament Reconstruction

Background

Biomechanics and anterior cruciate ligament injury mechanisms differ in males and females. There is a need for more data on between-limb biomechanical differences after anterior cruciate ligament reconstruction (ACLR) in females.

Purpose

To explore biomechanical asymmetries throughout the kinetic chain during the single-legged (SL) and double-legged (DL) countermovement jump (CMJ) and drop jump (DJ) in female athletes after ACLR.

Study Design

Descriptive laboratory study.

Methods

Kinematic and kinetic between-limb differences were analyzed during the SL and DL CMJ and DJ in 67 female athletes 9 months after ACLR. Biomechanical and performance asymmetries between limbs during the jumps and isokinetic strength testing were analyzed with statistical parametric mapping. The entire stance phase was used for the paired t tests of the biomechanical variables, with Cohen d effect sizes of significant portions of the stance phase (reported as % of stance) calculated in a point-by-point manner.

Results

Decreased vertical ground-reaction force, internal knee abduction moment, knee internal rotation angle, hip external rotation angle, internal ankle eversion, and external rotation moments were seen in the ACLR limb during all 4 vertical jump tests. The greatest number and highest value of differences were found during the DLDJ, with asymmetries having medium to large effect sizes. They tended to appear more frequently in the concentric phase (50% to 100% of stance) during the SLCMJ and DLCMJ and in the eccentric (0% to 49% of stance) and concentric (50% to 100% of stance) phase during the SLDJ and DLDJ. For the SLCMJ, SLDJ, and quadriceps strength, performance asymmetries of >15% were detected but not for change of direction.

Conclusion

The findings suggest that return-to-play testing in female athletes should examine the entire stance phase and include assessments of kinetic and kinematic variables throughout the kinetic chain. Greater deficits were highlighted in the DJ than in the CMJ, and greater performance asymmetries were evident in the SL tasks, with greater kinetic and kinematic and compensatory strategies evident in the DL tests.

Clinical Relevance

Biomechanical analysis focusing on contralateral compensation strategies and sex-specific interventions are necessary before return to play.

Successful ACL repair by dynamic intraligamentary stabilisation is non-inferior in functional performance and worse in proprioception compared to healthy controls in a case-matched study

Purpose

The primary aim of this study was to assess non-inferiority in functional performance of the knee after dynamic intraligamentary stabilisation (DIS) surgery at a minimal follow-up of 1 year compared to healthy controls, based on limb symmetry index (LSI) of the single leg hop test (SLH). Additionally, functional performance based on the single leg triple hop test (SLTH) and side hop test (SH), proprioception and subjective outcome were evaluated.

Methods

A total of 45 DIS patients were 1-to-1 matched to a healthy control. Functional performance was evaluated by LSI and absolute values on the SLH, SLTH and SH. Proprioception was assessed by joint position sense (JPS) test and International Knee Documentation Committee (IKDC) scores were obtained.

Results

Non-inferiority in functional performance after DIS compared to healthy controls was confirmed based on the mean LSI of the SLH and SLTH (97.6% vs. 99.6% and 97.5% vs. 100.6%, respectively) and non-confirmed on the SH (98.8% vs. 100.0%, respectively). No significant differences were found in absolute value of the SLH and SLTH and a significantly higher absolute value of the SH was found in the DIS group (p = 0.01). JPS absolute angular error was significantly higher in the DIS group compared to the control group (p = 0.01). The median IKDC score of the DIS group was significantly lower (92, IQR 85-95) than the control group (100, IQR 99-100), p < 0.001.

Conclusions

In conclusion, functional performance after DIS was confirmed non-inferior compared to healthy controls based on the SLH and SLTH, although non-confirmed on the SH.

Level of evidence

Level III.

Association of the COVID-19 Pandemic With Outcomes After Anterior Cruciate Ligament Reconstruction: A Retrospective Comparative Study Examining Changes in Health Care Access, Delivery, and Functional Outcomes

Background

Structured rehabilitation optimizes outcomes and reduces reinjury risk after anterior cruciate ligament reconstruction (ACLR). The coronavirus 2019 (COVID-19) pandemic interrupted standard rehabilitation, possibly affecting ACLR outcomes.

Purpose

To characterize changes to ACLR functional outcomes related to the COVID-19 pandemic.

Study Design

Cohort study; Level of evidence, 3.

Methods

Patients who underwent ACLR between June 11, 2019, and March 11, 2020, (postpandemic group) were compared retrospectively with those who underwent ACLR the year before (June 11, 2018, to March 11, 2019). A mixed-effects linear regression model was used to estimate group differences in isokinetic quadriceps testing. A Kaplan-Meier analysis assessed the probability of achieving >90% limb symmetry index (LSI) for isokinetic quadriceps strength at 60 deg/s and passing all return-to-sport functional outcomes at 1 year postoperatively.

Results

A total of 176 patients (80 in the control group and 96 in the postpandemic group) were included. The rate of achieving >90% LSI in isokinetic strength at 60 deg/s at 1 year postoperatively was 39% (95% CI, 27%-49%) for the control group versus 22% (95% CI, 13%-30%) for the postpandemic group (P = .01). Similarly, the rate of achieving >90% LSI in all functional tests at 1 year postoperatively was 15% (95% CI, 7%-22%) for the control group versus 7% (95% CI, 2%-12%) for the postpandemic group (P = .04). The number of in-person physical therapy visits per patient was 25.8 ± 6.8 in the control group versus 24.4 ± 7.5 in the postpandemic group (P = .23). Only the postpandemic group accessed physical therapy using remote telemedicine. Each additional telehealth rehabilitation visit was associated with a 1-week delay in achieving >90% LSI in isokinetic quadriceps strength for the postpandemic group.

Conclusion

The COVID-19 pandemic was associated with a decrease in lower extremity strength and a lower probability of achieving limb symmetry and passing the criteria for return to sport at 1 year postoperatively. These results were not due to lack of access to physical therapy.

Higher Unilateral Muscle Imbalance at the Contralateral Knee 6 Months after Anterior Cruciate Ligament Reconstruction

There are a considerable number of patients who, after anterior cruciate ligament reconstruction (ACL), suffer from relapses or reduced performance. Data collected from isokinetic dynamometry can provide useful information on the condition of the knee during rehabilitation. Seventy-one young sports patients with ACL reconstruction performed concentric (CON) isokinetic dynamometry (CON/CON 90°/s and CON/CON 240°/s) to assess the muscle strength of the quadriceps (Q) and hamstrings (H) in both knees at 6 months after ACL reconstruction. Limb symmetry index (LSI) and the H/Q ratio were calculated. Comparative statistical tests and multivariate regression were performed. At 90°/s, 57 patients (80.3%) had an LSI below 90% for quadriceps and 28 (60.6%) for hamstring. The number of imbalanced patients according to H/Q ratio was higher in the non-operated knee (n = 56, 78.9%) (p < 0.001). At 240°/s, 49 cases (69.1%) had LSI values above 90% for quadriceps and 37 (52.1%) for hamstrings. Regarding H/Q, imbalanced cases were higher in the non-operated limb (n = 60, 84.5%) (p < 0.001). Strength data at 6 months after ACL reconstruction and post-operative rehabilitation indicated greater unilateral (H/Q) muscle imbalance in the non-operated knee than in the operated knee. Most patients did not achieve the adequate LSI values.

Hopping backward to move forward: Single-leg backward hopping can better detect decreased quadriceps strength induced by a fatigue protocol compared to forward and vertical hopping

BACKGROUND

Deficits in quadriceps strength of the injured leg have been observed in patients following anterior cruciate ligament (ACL) reconstructions and may contribute to ACL re-injury risk. Single-leg forward hopping is a widely used task for assessing knee function in patients following ACL reconstructions as it has been shown not to be particularly challenging to the knee. This study aimed to quantify the effect of decreased quadriceps strength induced by a fatigue protocol on hopping performance and lower limb mechanics in single-leg forward, vertical, and backward hopping.

METHODS

Thirty-four injury-free participants performed single-leg forward, vertical, and backward hopping on both legs pre- and post-fatigue, with 1 leg experiencing a fatigue protocol. Peak moments, power, and work of hip, knee, and ankle joints were quantified during the jumping phase. Hopping performance and bilateral asymmetries in performance were assessed.

RESULTS

Single-leg backward hopping demonstrated the greatest knee moments, power, and work compared to forward and vertical hopping, regardless of leg and fatigue. Fatigue protocol resulted in significantly less knee moments, power, and work, and decreased performance of the fatigued leg among all tasks. Bilateral symmetries in hopping performance decreased in post-fatigue, with the greatest decrease in backward hopping.

CONCLUSION

The greater sensitivity of the backward hopping to detect quadriceps fatigue suggests it may act as a better or at least an additional metric to evaluate quadriceps strength deficits. The findings may contribute to the development of a clinically applicable and valid strength assessment to monitor the rehabilitation progress in patients following ACL reconstructions.

Preoperative Psychological Competitive Ability Is Associated With Emotional States Six Months After Anterior Cruciate Ligament Reconstruction With Hamstring Autograft: A Prospective Study

Background Psychological state has been reported as one of the factors strongly related to a return to sports after anterior cruciate ligament (ACL) reconstruction. However, its relationship with the emotional state remains unclear. The aim of this study was to investigate whether patients who have undergone ACL reconstruction and have a higher preoperative psychological competitive ability have a better emotional status preoperatively and six months postoperatively. Methods Patients with a Tegner activity score of ≥6 who underwent ACL reconstruction between 2015 and 2020 were divided into two groups according to their grades on the Diagnostic Inventory of Psychological Competitive Ability for Athletes (DIPCA.3). The emotional states preoperatively and at six months postoperatively were assessed using the Profile of Mood States Second Edition (POMS2) and compared between the two groups. Furthermore, the possibility of returning to sports was compared between the groups based on participation in the entire practice at six months postoperatively. Results Eighty-four patients were included and divided into the high (DIPCA.3 grades ≥4, n = 23) and low (DIPCA.3 <4, n = 61) groups. Vigor-activity and friendliness were significantly higher in the high group than in the low group preoperatively. The difference was even greater at six months after ACL reconstruction. In addition, the high group showed significantly better results postoperatively for fatigue-inertia and total mood disturbance. Rates of return to sports did not differ significantly between the high and low groups (56.5% vs. 54.1%). Conclusions Those with a higher preoperative psychological competitive ability were in a positive emotional state preoperatively and six months after ACL reconstruction. However, the psychological competitive ability did not affect the rate of participation in the entire practice at six months postoperatively.

Validity, Agreement and Reliability of the ForceFrame Dynamometer in Patients with Anterior Cruciate Ligament Injury

Background

Restoring maximal muscle strength of the knee extensors (KE) and knee flexors (KF) following anterior cruciate ligament (ACL) injury and ACL reconstruction is of great importance to reduce the re-injury rate after ACL reconstruction and to reduce the risk of knee osteoarthritis. Therefore, it is essential that clinicians and healthcare providers use valid and reliable measures to assess knee muscle strength to ensure a safe return to sport.

Purpose

To evaluate the reliability (test-retest reliability, inter-tester reliability and test-retest agreement) and validity (concurrent validity, convergent validity and ForceFrame (FF) vs. isokinetic dynamometer (ID) agreement) of the ForceFrame (FF) dynamometer during isometric testing of the knee extensors and flexors.

Study Design

Cross-sectional study.

Material and Methods

Twenty-seven participants with ACL injury or reconstruction were recruited for participation in this study. maximal voluntary isometric contration (MVIC) of the knee extensors and flexors was tested on two separate days. Day one included validity assessments with FF, a gold-standard ID and a handheld dynamometer (HHD). Day two included reliability assessments with FF performed by two assessors. Main outcome measures were day-to-day test-retest reliability and agreement and inter-tester reliability of FF, and concurrent validity (FF vs. an ID and a HHD). Reliability was tested as test-retest and inter-tester reliability using interclass correlation coefficient (ICC), while agreement was tested using Bland & Altman plots with limits of agreement (LOA), standard error of measurement (SEM) and smallest detectable change (SDC). Concurrent validity between FF, ID, and HHD was assessed using Pearson's correlations and mean difference was evaluated by Bland & Altman plots.

Results

Twenty-seven participants (10 females, 17 males) with a median age of 25 years (range 19-60) were included in this study. There was a good day-to-day test-retest reliability for MVIC of KE (ICC=0.77, CI95:0.48-0.90) and KF (ICC=0.83, CI95:0.61-0.92) and excellent inter-tester reliability for MVIC of KE (ICC=0.97, CI95:0.94-0.98) and KF (ICC=0.93, 95CI:0.85-0.97). Standard error of measurement (SEM) was 8% and 9%, while the smallest detectable change (SDC) was 22% and 27% for KE and KF, respectively. FF showed fair concurrent validity compared to ID for KE (r=0.56), poor concurrent validity for knee flexors (KF (r=0.24) and compared to HHD a moderate correlation for KE (r=0.74) and poor correlation for KF (r=0.12). Bland & Altman plots between FF and the ID showed a mean difference of -0.51 Nm/kg for KE and -0.32Nm/kg for KF.

Conclusions

FF can be used to obtain reliable and valid results to assess MVIC of the KE, but not the KF. It should be noted that absolute results produced by the FF may be considered an underestimation of actual MVIC. The test position to assess KF in FF does not appear to be optimal, and different test-positions may be considered.

Level of evidence

Level 3.

Comparison of Time Needed to Meet Common Rehabilitation Milestones After Anterior Cruciate Ligament Reconstruction According to Graft Type

Background

The use of bone-patellar tendon-bone (BPTB) and hamstring tendon (HT) autografts is common in anterior cruciate ligament reconstruction (ACLR). After ACLR, patients typically progress through specific rehabilitation milestones, and graft type may play a role in patient progression.

Purpose

To compare the time to meet rehabilitation milestones between BPTB and HT autografts after ACLR.

Design

Cohort study; Level of evidence, 3.

Methods

This was a single-institution study on patients who underwent ACLR with either BPTB or HT autograft between June 2018 and July 2021. The primary outcomes were time to meet return-to-sport criteria, including >90% limb symmetry index (LSI) for isokinetic quadriceps and hamstring strength, horizontal hop, 4-crossover hop, and single-hop height. The time to satisfaction of each criterion was compared between graft groups using Wilcoxon tests and Cox proportional hazards models.

Results

Included in the analysis were 410 participants who underwent ACLR with either BPTB (n = 232) or HT (n = 178). The BPTB group took longer to achieve >90% LSI for knee extension than HT (11.1 ± 4.1 vs 7.63 ± 2.8 months; P < .001). Similarly, the BPTB group took longer than the HT group to achieve >90% LSI for horizontal hop (11.4 ± 3.5 vs 9.82 ± 2.8 months; P < .001), 4-crossover hop (11.8 ± 3.6 vs 10.4 ± 2.8 months; P = .002), and single-hop height testing (11 ± 3.7 vs 8.81 ± 3.2 months; P < .001). The median time to achieve >90% LSI for hamstring strength was similar between groups (7.18 ± 3 vs 7.56 ± 3.1 months; P = .2).

Conclusion

Patients that underwent ACLR with BPTB autograft took longer than patients with HT to meet commonly used postoperative rehabilitation milestones. Clinicians should consider these differences when guiding patients regarding graft choice, postoperative expectations, and rehabilitation.

Knowledge and awareness of anterior cruciate ligament injury among Turkish professional athletes: an online survey

The purpose of this study was to assess the awareness and knowledge of professional team sport athletes about ACL injuries, injury prevention programs, and the return to sports after ACL injuries. A total of 419 athletes representing soccer, basketball, volleyball and handball sports were included in the study. We utilized a 15-item self-report survey to assess the awareness of athletes about ACL injury, ACL injury prevention program, and return to sport after ACL injuries. Male and soccer players participated in prevention programs more than female athletes (p = 0.001). Participation in prevention programs was significantly higher in the ≥ 18 years old group than in the < 18 years old group (p = 0.040). Participants who were informed about ACL injuries were 8.4 times more likely to participate in the ACL injuries prevention program than others (OR: 8.38, 95% CI: 3.823-18.376, p < 0.001). The majority of participants believed that return to sport after ACL injury takes 6 months and 81.4% of them thought that it is not possible to do sport without an ACL. This study revealed that the awareness and performance of ACL prevention training programs among professional team sport athletes were insufficient. The athletes' knowledge regarding return to sports after ACL injuries was also inadequate. Improving athletes' knowledge of ACL injuries may lead to increased participation in ACL injury prevention programs. Thus, the provision of tailored educational interventions to athletes could potentially enhance their awareness and understanding of ACL injuries, consequently contributing towards the prevention of such injuries.

Limitations of Separating Athletes into High or Low-Risk Groups based on a Cut-Off. A Clinical Commentary

Background

Athlete injury risk assessment and management is an important, yet challenging task for sport and exercise medicine professionals. A common approach to injury risk screening is to stratify athletes into risk groups based on their performance on a test relative to a cut-off threshold. However, one potential reason for ineffective injury prevention efforts is the over-reliance on identifying these 'at-risk' groups using arbitrary cut-offs for these tests and measures. The purpose of this commentary is to discuss the conceptual and technical issues related to the use of a cut-off in both research and clinical practice.

Clinical Question

How can we better assess and interpret clinical tests or measures to enable a more effective injury risk assessment in athletes?

Key Results

Cut-offs typically lack strong biologic plausibility to support them; and are typically derived in a data-driven manner and thus not generalizable to other samples. When a cut-off is used in analyses, information is lost, leading to potentially misleading results and less accurate injury risk prediction. Dichotomizing a continuous variable using a cut-off should be avoided. Using continuous variables on its original scale is advantageous because information is not discarded, outcome prediction accuracy is not lost, and personalized medicine can be facilitated.

Clinical Application

Researchers and clinicians are encouraged to analyze and interpret the results of tests and measures using continuous variables and avoid relying on singular cut-offs to guide decisions. Injury risk can be predicted more accurately when using continuous variables in their natural form. A more accurate risk prediction will facilitate personalized approaches to injury risk mitigation and may lead to a decline in injury rates.

Level of Evidence

5.

Anterior Cruciate Ligament Tears in Soccer Players

Anterior cruciate ligament (ACL) injuries to soccer players present unique challenges in sports medicine, given the sport's global prevalence and intricate injury dynamics. These injuries, especially in the youth and female demographic, have become a substantial concern in sports medicine. This review explores the epidemiology, mechanism of injury, diagnostic procedures, treatment modalities, and rehabilitation strategies related to ACL tears within the soccer community. Progress in diagnostics, treatments, and rehabilitation underscores the importance of evidence-based approaches. As soccer continues its ascent in popularity, addressing the specific risks and nuances of ACL injuries in this context remains of paramount significance.

Predicting the Recovery of Isokinetic Knee Strength 6 Months After Anterior Cruciate Ligament Reconstruction

Background

The limb symmetry index (LSI) is a metric of strength restoration. It is key to successfully return to sports after anterior cruciate ligament (ACL) reconstruction. The threshold for return to sports is generally considered an LSI of ≥85%.

Purpose

To develop a statistical model for predicting the recovery of knee extension and flexion strength (with LSI ≥85%) at 6 months after ACL reconstruction.

Study Design

Case-control study; Level of evidence: 3.

Methods

Patients who underwent arthroscopic ACL reconstruction between November 2015 and December 2020 were included. The patients were classified into 2 groups: "pass" if the LSI at 6 months postoperatively was ≥85% and "fail" if the LSI was <85%. Factors in 25 categories with 74 levels, including patient characteristics, periarticular procedures, intra-articular lesions and treatment, and perioperative management, were collected. A multivariable logistic regression combined with backward variable elimination was used to determine the predictive parameters for recovery of knee extension and flexion strength.

Results

A total of 948 patients were included. Graft site, preoperative isokinetic strength, treatment of meniscal injury, and injured side (left vs right) were identified as general predictors for both knee extension and flexion strength. For knee extension strength, age at injury and partial weightbearing duration were identified as additional predictors. For knee flexion strength, type of meniscal injury, surgeon volume, cartilage procedures, and periarticular procedures were identified as additional predictors. The Nagelkerke R 2 of the final model was 0.178, and the c-statistic was 0.716 (95% CI, 0.676-0.754). The Hosmer-Lemeshow test indicated good calibration (P = .879).

Conclusion

Several factors including preoperative isokinetic strength, treatment of meniscal injuries, left vs. right side and graft site were found to predict recovery of ≥85% LSI in knee extension and flexion strength. Despite the numerous factors that were analyzed, the predictive power was moderate (c-statistic = 0.716), indicating there were other nonincluded factors that significantly influence strength performance at 6 months postoperatively.

Sure Steps: Key Strategies for Protecting Basketball Players from Injuries-A Systematic Review

Background: Basketball is a high-intensity sport, which includes actions such as jumping, changes of direction, accelerations, and decelerations, which generates fatigue situations that may increase the risk of injury. Specifically, the joints at greatest risk are the ankle and knee, with ankle sprains and anterior cruciate ligament (ACL) tears being the most prevalent injuries. There are several strategies aimed at reducing the incidence, based on training methods or other prophylactic measures. Therefore, the purpose of the study is to perform a systematic review of the different injury prevention strategies in competitive-level basketball players with respect to general injuries, ankle sprains, and ACL injuries. Methods: For this purpose, the PRISMA methodology was applied, performing a search in three databases (PubMed, SPORTDiscus, and Cochrane) between 25 September 2023 and 8 October 2023. Results: A total of 964 articles were identified, out of which 283 were duplicates and 644 were discarded. Out of the remaining 37, 23 were excluded because they did not meet the inclusion criteria; therefore, 14 articles were finally included. With respect to general injuries, 8 out of 14 studies reviewed them. Concerning ankle sprains, 7 studies specifically analyzed them. Finally, 3 studies focused on ACL injuries. Conclusions: Training programs that combine different contents, known as neuromuscular training, including strength work, stabilization or core, mobility, and agility are the most effective for both general injuries and ACL injuries. For ankle sprains, the most effective measures are training programs based on analytical ankle stability exercises and the use of ankle braces. Adherence to prevention programs is essential, so they can be included as part of the warm-up. Other strategies such as training load control, functional assessment, or rule modification are not used in the included articles, so their effectiveness as prophylactic methods could not be justified.

Angle-Specific Analysis of Isokinetic Quadriceps and Hamstring Strength at 6 and 12 Months After Unilateral ACL Reconstruction

BACKGROUND

Quadriceps and hamstring strength deficits are related to the increased risk of reinjury after anterior cruciate ligament reconstruction (ACLR).

HYPOTHESIS

Knee angle-specific quadriceps and hamstring strength differences would be observed in patients with ACLR 6 and 12 months after surgery.

STUDY DESIGN

Case-series.

LEVEL OF EVIDENCE

Level 4.

METHODS

A total of 23 postprimary unilateral ACLR patients followed-up at 6 and 12 months postoperatively and 25 controls were included. Isokinetic knee extension and flexion strength were evaluated at 60 deg/s from 20° to 90°. Statistical parametric mapping were performed to explore the angle-specific strength and the limb symmetry index (LSI).

RESULTS

At 6 months postoperatively, the reconstructed leg demonstrated lower knee extension and flexion strength than the contralateral (20°-77°, 24°-90°) (P < 0.01) and control legs (22°-90°, 40°-82°) (P < 0.01). From 6 months to 12 months, knee extension (60°-90°) and flexion (20°-79°) strength improved in the reconstructed leg (P < 0.05), while LSI remained unchanged (P > 0.02). At 12 months, knee extension strength differences persisted in the reconstructed leg compared with the contralateral (20°-81°) and controls (25°-63°) (P < 0.01). ACLR patients had lower LSI of knee extension strength at 6 (20°-59°) and 12 (24°-57°) months postoperatively than the controls (P < 0.02).

CONCLUSION

The reconstructed leg exhibited differences in knee extension strength compared with the contralateral and control legs. Although bilateral knee extension strength increased from 6 to 12 months postoperatively, LSI did not show improvement during this period.

CLINICAL RELEVANCE

Quadriceps restoration was observed only in knee flexion angles greater than 60° compared with controls. Future studies should investigate whether knee extension strength, especially in lower flexion angles, can be enhanced through rehabilitation programs. Furthermore, assessing the impact of this improvement on long-term outcomes and reinjury risk in ACLR patients is warranted.

Distributed Wearable Ultrasound Sensors Predict Isometric Ground Reaction Force

Rehabilitation from musculoskeletal injuries focuses on reestablishing and monitoring muscle activation patterns to accurately produce force. The aim of this study is to explore the use of a novel low-powered wearable distributed Simultaneous Musculoskeletal Assessment with Real-Time Ultrasound (SMART-US) device to predict force during an isometric squat task. Participants (N = 5) performed maximum isometric squats under two medical imaging techniques; clinical musculoskeletal motion mode (m-mode) ultrasound on the dominant vastus lateralis and SMART-US sensors placed on the rectus femoris, vastus lateralis, medial hamstring, and vastus medialis. Ultrasound features were extracted, and a linear ridge regression model was used to predict ground reaction force. The performance of ultrasound features to predict measured force was tested using either the Clinical M-mode, SMART-US sensors on the vastus lateralis (SMART-US: VL), rectus femoris (SMART-US: RF), medial hamstring (SMART-US: MH), and vastus medialis (SMART-US: VMO) or utilized all four SMART-US sensors (Distributed SMART-US). Model training showed that the Clinical M-mode and the Distributed SMART-US model were both significantly different from the SMART-US: VL, SMART-US: MH, SMART-US: RF, and SMART-US: VMO models (p < 0.05). Model validation showed that the Distributed SMART-US model had an R2 of 0.80 ± 0.04 and was significantly different from SMART-US: VL but not from the Clinical M-mode model. In conclusion, a novel wearable distributed SMART-US system can predict ground reaction force using machine learning, demonstrating the feasibility of wearable ultrasound imaging for ground reaction force estimation.

Qualitative and quantitative return-to-sport test battery and second anterior cruciate ligament injury risk factors

ABSTRACT

Objective

To determine risk factors for second anterior cruciate ligament (ACL) injury following primary ACL reconstruction (ACLR) using return-to-sport (RTS) tests consisting of qualitative and quantitative measures in young athletes.

Methods

A case-control study design was used, and a retrospective review of adolescent athletes after primary ACLR was performed. All athletes completed an RTS test consisting of qualitative and quantitative assessments and psychological assessments with the Tampa Scale of Kinesiophobia. Athlete demographics, surgical characteristics and sports participation were also examined. A binary logistic regression was performed to verify an independent association between risk factors and second ACL injury using adjusted OR (aORs), 95% CI and p<0.05.

Results

In 72 eligible athletes, 12 (16.7%) suffered a second ACL injury. The mean Tegner activity level was 8.4+1.1, and the mean time from ACLR to RTS test completion was 10.4+2.9 months. One variable that showed the lowest p-value in the preliminary analysis was entered into the binary logistic regression model, which resulted in that qualitative assessment of knee valgus during the sidestep cut was associated with second ACL injury (aOR=4.64, 95% CI: 1.18 to 18.23, p=0.03).

Conclusion

Athletes who demonstrated excessive dynamic knee valgus on the involved limb during the sidestep cut were approximately 4.6 times more likely to suffer a second ACL injury.

Assessing the Relationship of Psychological Sport Readiness, Single-leg Vertical Jump, and Non-Sagittal Single-Leg Hops to Quadriceps Strength After Anterior Cruciate Ligament Reconstruction

Background

Limitations exist with current ACLR functional testing assessments that may be mitigated by including single-leg multi-directional testing.

Hypothesis/Purpose

To compare Anterior Cruciate Ligament-Return to Sport after Injury Scale (ACL-RSI) scores, limb symmetry index (LSI) of the single-leg vertical jump (SLVJ), single-leg medial rotation hop (SLMRH), single-leg lateral hop (SLLH), and isokinetic quadriceps strength between participants with an ACLR and healthy controls and assess predictors of quadriceps strength asymmetry. It was hypothesized that ACL-RSI scores and LSIs for all tests would differ between ACLR and healthy control groups and within the ACLR group a strong correlation would exist between all outcome measures and quadriceps strength.

Study Design

Cross-Sectional Study.

Methods

Twenty-six participants with an ACLR (median 13 months after surgery) and twenty-six matched healthy controls were recruited to participate in this study. Performance was assessed via SLVJ, SLMRH, SLLH, and isokinetic quadriceps strength. Between-group comparisons were made with independent t-tests and Mann-Whitney U test. Within the ACLR group, bivariate correlation and multivariate regression analysis were performed to assess the relationship between the outcome measures and quadriceps strength asymmetry.

Results

Significant between-limb differences were only identified in the ACLR group (p< 0.05): SLVJ LSI: 88.5%, SLMRH LSI: 93.6%, SLLH LSI: 92.7%, quadriceps strength LSI 80.9% - 83.9%, which were significantly lower (p <0.05) than the healthy control group. Within the ACLR group, a moderate-strong significant (p < 0.05) correlations existed with quadriceps strength and SLVJ (r=0.44-0.65), SLMRH (r =0.43-0.83), and SLLH (r=0.54-0.63); while ACL-RSI had a weak non-significant (p > 0.05) correlation with quadriceps strength (r= 0.12-0.30).

Conclusion

Single-leg multidirectional test LSIs were less in ACLR participants than matched healthy controls and all were directly related to quadriceps strength. Psychological readiness to return to sport was not related to quadriceps strength.

Hop Distance Symmetry Moderately Reflects Knee Biomechanics Symmetry During Landing But Not For Controlled Propulsions

Background

Landing with poor knee sagittal plane biomechanics has been identified as a risk factor for Anterior Cruciate Ligament (ACL) injury. However, it is unclear if the horizontal hop test battery reflects knee function and biomechanics.

Hypothesis/Purpose

To investigate the correlation between clinical limb symmetry index (LSI) and landing and propulsion knee biomechanics during the hop test battery using markerless motion capture.

Study Design

Cross-sectional biomechanics laboratory study.

Methods

Forty-two participants with and without knee surgery (age 28.0 ± 8.0 years) performed the hop test battery which consisted of a single hop for distance, crossover hop, triple hop, and 6-m timed hop in the order listed. Eight high speed cameras were used to collect simultaneous 3D motion data and Theia 3D (Theia Markerless Inc.) was used to generate 3D body model files. Lower limb joint kinematics were calculated in Visual3D. Correlation (Spearman's ρ) was computed between clinical LSI and symmetry in peak and initial contact (IC) knee flexion angle during propulsion and landing phases of each movement.

Results

In the single hop, clinical LSI showed positive correlation with kinematic LSI at peak landing (ρ= 0.39, p=0.011), but no correlation at peak propulsion (ρ= -0.03, p=0.851). In the crossover hop, non-significant correlations were found in both propulsion and landing. In the triple hop, positive correlation was found at peak propulsion (ρ= 0.38, p=0.027), peak landing (ρ= 0.48 - 0.66, p<0.001), and last landing IC (ρ= 0.45, p=0.009). In the timed hop, peak propulsion showed positive correlation (ρ= 0.51, p=0.003).

Conclusions

Single hop and triple hop distance symmetry reflected landing biomechanical symmetry better than propulsion symmetry. Poor scores on the hop test battery reflect asymmetrical knee landing biomechanics, emphasizing the importance of continuing to use the hop test battery as part of clinical decision making.

Level of Evidence

3b.

Impaired Symmetry in Single-Leg Vertical Jump and Drop Jump Performance 7 Months After ACL Reconstruction

Background

Anterior cruciate ligament reconstruction (ACLR) continues to be associated with a variable rate of return to sports and a concerning rate of further anterior cruciate ligament injury. Persistent functional deficits may explain these results and support the need to keep exploring lower limb functional indexes, especially during vertical jumping. This would help improve rehabilitation through the return-to-sports continuum and improve postoperative outcomes.

Hypothesis

Vertical jumping performance indexes are impaired among patients 7 months after ACLR.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

A total of 202 patients who underwent ACLR and 50 healthy participants performed single-leg vertical jump (SLVJ) and single-leg drop jump (SLDJ) testing. Jump height (H) as well as reactive strength index (RSI) were assessed and the limb symmetry index (LSI) of each parameter was compared between both groups. Vertical jumping indexes were also compared between healthy participants and the injured and contralateral legs of ACLR patients. Frequency analysis (chi-square test) of participants exhibiting an LSI >90% for each parameter was calculated in both groups. The level of association between SLVJ-H, SLDJ-H, and SLDJ-RSI was evaluated using the Pearson coefficient (r).

Results

At 6.6 ± 0.7 months (mean ± SD) postoperatively, participants after ACLR exhibited poorer LSI than the control group for all parameters (79.1 ± 14.8 vs 93.9 ± 4.5, 77.3 ± 14.6 vs 93.4 ± 5.2, and 71.9 ± 17.4 vs 93.4 ± 3.8; all P < .001; for the SLVJ-H, SLDJ-H, and SLDJ-RSI, respectively). Vertical jumping performance was lower on both injured and contralateral legs compared with healthy participants (all P < .001). Only 27%, 25%, and 16% of the ACLR patients exhibited an LSI >90% for the SLVJ-H, SLDJ-H, and SLDJ-RSI, respectively, in comparison with 80%, 72%, and 86% in the control group. Moderate correlations were observed between SLDJ-H and SLVJ-H (r = 0.494; P < .001) as well as between SLDJ-RSI and SLVJ-H (r = 0.488; P < .001) in the ACLR group.

Conclusion

Vertical jumping indexes (both symmetry and absolute values) were highly impaired 7 months after ACLR. Deficits were more marked for reactive strength ability. Clinicians should focus on restoring vertical jumping abilities to improve functional performance after ACLR.

The effects of isokinetic training in athletes after knee surgery: a systematic review

PURPOSE

To review the effectiveness of isokinetic training as an alternative method to traditional isotonic resistance training.

MATERIALS AND METHODS

Researchers examined data from PubMed, CENTRAL, MEDLINE COMPLETE, and Web of Science until February 2023. A total of 365 entries were obtained from databases, including studies that analyzed the effects of isokinetic vs. isotonic-based rehabilitation in athletes (16-50 years) after a surgical knee intervention. Return to sport (RTS), strength of the flex/extensor compartment of the thigh, muscle mass of the thigh, and knee function were screened as main outcomes. Two reviewers independently screened the studies for eligibility and assessed the risk of bias of the included ones.

RESULTS

Six studies involving 181 athletes were included. Isokinetic training demonstrated significant benefits in peak torque for knee flexor-extensor muscles in four studies. Two studies favored isokinetic training over isotonic for strength. Muscle mass findings were mixed, with one study favoring isokinetic significantly and two showing no significant differences. In terms of returning to sport, the isotonic group displayed slightly better limb symmetry index values, but without significance. Isokinetic training outperformed isotonic in two functionality questionnaire studies, while two others showed no significant differences.

CONCLUSIONS

Isokinetic training appears equally, if not more effective than isotonic, for restoring strength balance between hamstrings and quadriceps. This could lead to more favorable muscle mass changes. Isokinetic training also parallels isotonic rehabilitation for functional outcomes and meeting return-to-sport criteria. Therefore, isokinetic training should be included as one of the main strength restoration strategies after knee surgery, especially in early and middle rehabilitation stages.

REGISTRATION NUMBER

The present systematic review was registered on PROSPERO (registration number: CRD42022370398).

Judgement and Decision Making in Clinical and Return-to-Sports Decision Making: A Narrative Review

Making return-to-sport decisions can be complex and multi-faceted, as it requires an evaluation of an individual's physical, psychological, and social well-being. Specifically, the timing of progression, regression, or return to sport can be difficult to determine due to the multitude of information that needs to be considered by clinicians. With the advent of new sports technology, the increasing volume of data poses a challenge to clinicians in effectively processing and utilising it to enhance the quality of their decisions. To gain a deeper understanding of the mechanisms underlying human decision making and associated biases, this narrative review provides a brief overview of different decision-making models that are relevant to sports rehabilitation settings. Accordingly, decisions can be made intuitively, analytically, and/or with heuristics. This narrative review demonstrates how the decision-making models can be applied in the context of return-to-sport decisions and shed light on strategies that may help clinicians improve decision quality.

Not all patient-reported outcome measures are equivalent at two years compared to one year after anterior cruciate ligament reconstruction based on a retrospective analysis

OBJECTIVE

This article aims to assess for clinically important differences in patient-reported outcome measures (PROMs) at one and two years post anterior cruciate ligament reconstruction (ACLR).

METHODS

A retrospective comparison of prospectively collected PROMs for a single cohort who underwent a primary ACLR with or without associated meniscal surgery from 2016 to 2020 was assessed. Six externally validated PROMs were collected preoperatively and at standardized times postoperatively. Descriptive statistics and paired equivalence testing of PROMs at one and two years after surgery was completed using previously published or calculated minimal clinically important differences as upper and lower equivalence limits. A repeated measures analysis of PROMs that were not clinically equivalent at one and two years after surgery was completed to assess for a clinically significant difference. Subgroup analyses based on sex, age and associated meniscal injury were completed.

RESULTS

One-hundred and forty-five participants with a mean age of 28.7 years (standard deviation: 9.9 years) were included in the final analysis. All PROMs were clinically equivalent at two years compared to one year after ACLR except the quality of life and sport and recreation domains of the Knee Injury and Osteoarthritis Outcome Score (KOOS). The quality of life (mean difference (MD):12.3, P ​< ​0.01, effect size (η2): 0.65) and sport and recreation (MD: 8.78, P ​< ​0.01, η2: 0.50) domains of the KOOS were clinically different at two years compared to one year postoperatively. No major differences were found in the subgroup analyses compared to the entire included sample.

CONCLUSION

While most PROMs were equivalent at two years compared to one year after ACLR, the quality of life and sport and recreation domains of the KOOS, which reflect knee performance during higher demand activities, exhibited a clinically significant difference.

LEVEL OF EVIDENCE

IV.

Quadriceps Activation After Anterior Cruciate Ligament Reconstruction: The Early Bird Gets the Worm!

Arthrogenic Muscle Inhibition (AMI) is a phenomenon observed in individuals with joint injury or pathology, characterized by a reflexive inhibition of surrounding musculature, altered neuromuscular control, and compromised functional performance. After anterior cruciate ligament reconstruction (ACLR) one of the most obvious consequences of AMI is the lack of quadriceps activation and strength. Understanding the underlying mechanisms of AMI is crucial for developing effective therapeutic interventions. The surgical procedure needed to reconstruct the ACL has biochemical et physiological consequences such as inflammation, pain, and altered proprioception. These alterations contribute to the development of AMI. Therapeutic interventions aimed at addressing AMI encompass a multidimensional approach targeting pain reduction, inflammation management, proprioceptive training, and quadriceps activation. Early management focusing on pain modulation through modalities like ice, compression, and pharmacological agents help mitigate the inflammatory response and alleviate pain, thereby reducing the reflexive inhibition of quadriceps. Quadriceps activation techniques such as neuromuscular electrical stimulation (NMES) and biofeedback training aid in overcoming muscle inhibition and restoring muscle strength. NMES elicits muscle contractions through electrical stimulation, bypassing the inhibitory mechanisms associated with AMI, thus facilitating muscle activation and strength gains. Comprehensive rehabilitation programs tailored to individual needs and stage of recovery are essential for optimizing outcomes in AMI. The objective of this clinical viewpoint is to delineate the significance of adopting a multimodal approach for the effective management of AMI, emphasizing the integration of pain modulation, proprioceptive training, muscle activation techniques, and manual therapy interventions. Highlighting the critical role of early intervention and targeted rehabilitation programs, this article aims to underscore their importance in restoring optimal function and mitigating long-term complications associated with AMI.

Safety and Early Return to Sports for Early ACL Reconstruction in Young Athletes: A Retrospective Study

Background and Objectives: Although previous reports have shown that early anterior cruciate ligament (ACL) reconstruction is associated with an increased risk of stiffness, recommendations for delayed surgery are based on outdated literature. The advent of arthroscopic surgery and accelerated rehabilitation protocols warrants a reexamination of the optimal surgical timing. The purpose of this study was to investigate complications during early ACL reconstruction after injury in young athletes. Materials and Methods: A total of 87 patients (27 males and 60 females) were included in this study. Patients who underwent anatomic ACL reconstruction using hamstring autografts were evaluated. Patients under 25 years of age with a Tegner activity score greater than 6 were included and classified into three groups according to the time from injury to surgical treatment: one week from injury to surgery (early group), three to six weeks from injury to surgery (normal group), and three to six months from injury to surgery (delayed group). We evaluated the rates of various complications such as graft rupture, contralateral injury, the need for manipulation for loss of ROM, infection, and fracture around the knee up to 2 years postoperatively. In addition, we investigated postoperative muscle strength, Lysholm score, Tegner activity score, and period of the return to sport from injury. Results: Patients in the delayed group were younger than those in the other groups (p = 0.009). Patients in the early group had a lower range of motion than those in the other groups preoperationly. However, the 1-month postoperative range of motion was comparable between groups. Patients in the early group had greater postoperative Tegner activity scores than those in the other groups. The period of return to sport from injury in the delayed group was longer than in the other groups. There were no statistically significant differences in the postoperative complication rate, muscle strength, or Lysholm score. Conclusions: ACL reconstruction performed 1 week from injury to surgery in young athletic patients indicated the rate of complications were not significantly different among the groups. Early ACL reconstruction with no postoperative complications may be related to early return to sports and a high level of sports.

Changes in isometric mid-thigh pull peak force and symmetry across anterior cruciate ligament reconstruction rehabilitation phases

Background

Whether functionally relevant strength assessments, such as the isometric mid-thigh pull (IMTP), can be used either bilaterally or unilaterally to evaluate and guide rehabilitation progress in those with anterior cruciate ligament reconstruction (ACLR) is under-researched. This study assessed changes in peak force (PF) and asymmetry across 3 phases for bilateral and unilateral IMTP assessments in patients with ACLR. Peak isometric force from the IMTP was compared to peak torque from isokinetic dynamometry as well as against a cohort of healthy, uninjured individuals.

Method

Participants (ACLR, n = 15) completed bilateral and unilateral IMTP assessments at weeks 12 (baseline), 16 (phase 3), and 20 (phase 4) of rehabilitation to evaluate changes in PF and asymmetry. Asymmetry was evaluated using the asymmetry angle. Isometric data from the IMTP were compared to that from an isokinetic dynamometer as well as against a cohort of healthy, uninjured participants (n = 63) allowing for a detailed analysis of limb-specific force production.

Results

The PF during the bilateral IMTP increased for both the injured (0.94 N/kg) and uninjured (0.26 N/kg) limbs from baseline to phase 4, whereas the PF of the injured limb increased by 1.5 N/kg during the unilateral IMTP in the same time frame. Asymmetry values systematically reduced by ∼1% and ∼0.5% for the bilateral and unilateral IMTP tests from baseline to phase 4. Significant differences in PF of the injured limb were evident between those with ACLR and healthy controls across all phases (p = 0.022-0.001). The rate of progression in PF capacity was dependent on test type, amounting to 0.1 and 0.2 body weights per week for the bilateral and unilateral IMTP respectively. Small-to-large correlations (r = 0.12-0.88) were evident between IMTP PF and peak torque from the isokinetic dynamometer as well as between asymmetry metrics from both tests.

Conclusion

The findings suggest that IMTP PF has potential for monitoring changes in PF and asymmetry during the ACLR rehabilitation progress. Both injured limb and uninjured limb show improvement in force-generating capacity, implying a positive adaptation to rehabilitation protocols. The findings highlight that ACLR is a unilateral injury that requires bilateral rehabilitation.

Pattern of strength recovery differences Exist in Adolescent athletes after anterior cruciate ligament reconstruction when using quadriceps versus Hamstring tendon autograft

OBJECTIVES

To compare the timeline for post-operative quadriceps and hamstrings strength recovery following anterior cruciate ligament reconstruction (ACLR) using either a quadriceps tendon (QT) or hamstring tendon (HT) autograft.

METHODS

Patients (≤18 years) who underwent ACLR using autograft QT or HT were included. Isokinetic strength was extracted at 3, 6, and 12 months post-operatively. Effects of time and graft type on quadriceps or hamstring limb symmetry index (qLSI/hLSI) was assessed with two-way repeated measures ANOVA. Between group differences at each time point were assessed with unpaired t-tests. Chi-square and Kaplan-Meir analysis analyzed the proportions of subjects able to achieve ≥90% LSI.

RESULTS

A total of 75 subjects (QT n = 38 HT n = 37,15.8 years) were included. There were significant differences in qLSI, with greater symmetry within the HT group at all time points. A higher proportion of subjects with HT grafts were able to achieve ≥90% qLSI within 12 months of surgery (81% vs 45%, p = 0.001).

CONCLUSION

Compared to those with HT autografts, adolescents with QT autografts demonstrate a prolonged timeline for quadriceps recovery. While mean strength values above 90% are achieved, a significantly lower percentage of QT patients are able to achieve 90% qLSI by 12 months post-op.

Prolonged quadriceps latency during gait early after anterior cruciate ligament injury predicts radiographic knee osteoarthritis 6-years after anterior cruciate ligament reconstruction

BACKGROUND

The purpose was to explore quadriceps electromechanical function (quadriceps latency) during gait after anterior cruciate ligament injury as a predictor for radiographic knee osteoarthritis 6-years after anterior cruciate ligament reconstruction. Change in latency after preoperative physical therapy was also examined.

METHODS

Quadriceps latency (time between peak knee moment and quadriceps electromyography) was calculated before preoperative physical therapy (2.4 [0.5-7.5] months after anterior cruciate ligament injury) and after preoperative physical therapy in 24 athletes. Participants were dichotomized into osteoarthritis (Kellgren and Lawrence grade ≥ 2) and non-osteoarthritis groups at 6-years. Forward selection logistic regression was performed using z-score normalized quadriceps latency and demographics. A 2 × 2 repeated measure ANOVA was performed for quadriceps latency between groups before and after preoperative physical therapy.

FINDINGS

Quadriceps latency before preoperative physical therapy was the only predictor of 6-year radiographic osteoarthritis (p = 0.014, odds ratio [95% confidence interval] = 5.859 [1.435-23.924]). Time by group interaction was observed for quadriceps latency (p = 0.039, η2p = 0.179). In the osteoarthritis group, latency may reduce after training (before preoperative physical therapy = 115.7 ± 20.6 ms, after preoperative physical therapy = 99.5 ± 24.0 ms, p = 0.082).

INTERPRETATION

Prolonged latency after anterior cruciate ligament injury may predict post-traumatic knee osteoarthritis 6-years after anterior cruciate ligament reconstruction. Latency may shorten with preoperative physical therapy, yet athletes still moved on to develop osteoarthritis. Quadriceps function may need intervention immediately following anterior cruciate ligament injury for prevention of post-traumatic knee osteoarthritis.

Functional Return-to-Sport Testing Demonstrates Inconsistency in Predicting Short-Term Outcomes Following Anterior Cruciate Ligament Reconstruction: A Systematic Review

PURPOSE

To systematically review the relationship between functional testing at the time of return to sport (RTS) and short-term outcomes, such as second anterior cruciate ligament (ACL) tear and return to a preinjury level of sport, among athletes who underwent anterior cruciate ligament reconstruction (ACLR).

METHODS

A systematic literature search was performed in MEDLINE, EMBASE, Scopus, and Web of Science to identify studies examining athletes who underwent functional RTS testing and were followed for at least 12 months following ACLR. Studies were screened by 2 reviewers. A standardized template was used to extract information regarding study characteristics, ACLR information, functional test results, and risk factors associated with retear or reduced RTS.

RESULTS

Of the 937 studies identified, 22 met the inclusion criteria. The average time between ACLR and RTS testing was 8.5 months. Single leg hop for distance performance had no association with retear risk in any study and no association with RTS rates in most studies. Quadriceps strength had conflicting results in relation to retear risk, whereas it had no relationship with RTS rates. Rates of reinjury and RTS were similar between patients who passed and did not pass combined hop and strength batteries. Asymmetric knee extension and hip moments, along with increased knee valgus and knee flexion angles, demonstrated increased risk of retear.

CONCLUSIONS

Individual hop and strength tests that are often used in RTS protocols following ACLR may have limited and inconsistent value in predicting ACL reinjury and reduced RTS when used in isolation. Combined hop and strength test batteries also demonstrate low sensitivity and negative predictive value, highlighting conflicting evidence to suggest RTS testing algorithm superiority.

LEVEL OF EVIDENCE

Level IV, systematic review of Level I-IV studies.

Management of Anterior Cruciate Ligament Tears in Skeletally Immature Patients

PURPOSE OF REVIEW

Anterior cruciate ligament (ALC) tears are increasingly common in skeletally immature patients, as more children and adolescents participate in intensive sports training and specialization at increasingly younger ages. These injuries were historically treated nonoperatively, given concerns for physeal damage and subsequent growth disturbances after traditional ACL reconstruction techniques. However, there is now sufficient data to suggest superior outcomes with operative treatment, specifically with physeal-sparing and physeal-respecting techniques. This article reviews considerations of skeletal maturity in patients with ACL tears, then discusses surgical techniques, with a focus on their unique indications and outcomes. Additional surgical adjuncts and components of postoperative rehabilitation, which may reduce retear rates, are also considered.

RECENT FINDINGS

Current research shows favorable patient-reported outcomes and high return-to-sport rates after ACL reconstruction in skeletally immature patients. Graft rupture (ACL retear) rates are low, but notably higher than in most adult populations. Historically, there has been insufficient research to comprehensively compare reconstruction techniques used in this patient population. However, thoughtful systematic reviews and multicenter prospective studies are emerging to address this deficit. Also, more recent data suggests the addition of lateral extra-articular procedures and stringent return-to-sports testing may lower retear rates. Physeal-sparing and physeal-respecting ACL reconstructions result in stabilization of the knee, while respecting the growth remaining in children or skeletally immature adolescents. Future research will be essential to compare these techniques, given that more than one may be appropriate for patients of a specific age and skeletal maturity.

Regional healing trajectory of the patellar tendon after bone-patellar tendon-bone autograft harvest for anterior cruciate ligament reconstruction

Graft site morbidities after bone-patellar tendon-bone (BPTB) autograft harvest for anterior cruciate ligament reconstruction (ACLR) negatively impacts rehabilitation. The purpose of this study was to establish tendon structural properties 1-month after BPTB autograft harvest compared to the uninvolved patellar tendon, and subsequently to quantify the healing trajectory of the patellar tendon over the course of rehabilitation. Patellar tendon morphology (ultrasound) and mechanical properties (continuous shear wave elastography) from 3 regions of the tendon (medial, lateral, central) were measured in 34 participants at 1 month, 3-4 months, and 6-9 months after ACLR. Mixed models were used to compare tendon structure between limbs at 1 month, and quantify healing over 3 timepoints. The involved patellar tendon had increased cross-sectional area and thickness in all regions 1-month after ACLR. Thickness reduced uniformly over time. Possible tendon elongation was observed and remained stable over time. Tendon viscosity was uniform across the three regions in the involved limb while the medial region had higher viscosity in the uninvolved limb, and shear modulus was elevated in all three regions at 1 month. Viscosity and shear modulus in only the central region reduced over time. Statement of Clinical Significance: The entire patellar tendon, and not just the central third, is altered after graft harvest. Tendon structure starts to normalize over time, but alterations remain especially in the central third at the time athletes are returning to sport. Early rehabilitation consisting of tendon loading protocols may be necessary to optimize biologic healing at the graft site tendon.

Nonoperative Anterior Cruciate Ligament Injury Treatment

This article outlines the key points in the nonoperative treatment of an anterior cruciate ligament (ACL) injury. Initial evaluation and treatment of an acute knee injury, often performed by a physician with limited experience in the treatment of an ACL injury, follow the basic diagnostic workup that lead to the diagnosis. The principles of rehabilitation after ACL injury have changed from time based to criteria based, and the different phases based on physical criteria are described.

Repair potential of self-assembling peptide hydrogel in a mouse model of anterior cruciate ligament reconstruction

Purpose

Establishing zonal tendon-to-bone attachment could accelerate the anterior cruciate ligament reconstruction (ACLR) rehabilitation schedule and facilitate an earlier return to sports. KI24RGDS is a self-assembling peptide hydrogel scaffold (SAPS) with the RGDS amino acid sequence. This study aimed to elucidate the therapeutic potential of KI24RGDS in facilitating zonal tendon-to-bone attachment after ACLR.

Methods

Sixty-four C57BL/6 mice were divided into the ACLR + SAPS and ACLR groups. ACLR was performed using the tail tendon. To assess the maturation of tendon-to-bone attachment, we quantified the area of mineralized fibrocartilage (MFC) in the tendon graft with demeclocycline. Immunofluorescence staining of α-smooth muscle actin (α-SMA) was performed to evaluate progenitor cell proliferation. The strength of tendon-to-bone attachment was evaluated using a pull-out test.

Results

The MFC and maximum failure load in the ACLR + SAPS group were remarkably higher than in the ACLR group on Day 14. However, no significant difference was observed between the two groups on Day 28. The number of α-SMA-positive cells in the tendon graft was highest on Day 7 after ACLR in both the groups and was significantly higher in the ACLR + SAPS group than in the ACLR group.

Conclusion

This study highlighted the latent healing potential of KI24RGDS in facilitating early-stage zonal attachment of tendon grafts and bone tunnels post-ACLR. These findings may expedite rehabilitation protocols and shorten the timeline for returning to sports.

Level of Evidence

Not applicable.