After Anterior Cruciate Ligament Injury Research Articles

Determining Maximal Outcome Improvement Thresholds for Patient-Reported Outcome Measures After Primary ACL Reconstruction: A Mid-Term Follow-up Study Using the Anchor Method.

The clinical interpretation of patient-reported outcome measures (PROMs) after anterior cruciate ligament (ACL) reconstruction (ACLR) can be challenging. This study aimed to establish the clinical relevance of PROMs by determining maximal outcome improvement (MOI) thresholds at mid-term follow-up after primary ACLR. A total of 343 patients who underwent primary single-bundle ACLR using hamstring tendon autograft at our institute were included. Patients were queried with a 2-option anchor question regarding satisfaction with their current knee symptom state. The MOI of a PROM was calculated for each patient as the percentage of improvement normalized by the maximal possible improvement. The MOI threshold for each PROM was determined as the optimal cutoff value for predicting patient satisfaction based on receiver operating characteristic curve analysis. Multivariable logistic regression analyses were performed to identify predictors of achieving these thresholds. Subgroup analyses that stratified the time from injury to surgery within the cohort were performed, and MOI thresholds were recalculated within each of these subgroups. The PROMs evaluated in this study were the modified Lysholm Knee Score and the International Knee Documentation Committee Subjective Knee Evaluation Form (IKDC) score. The calculated MOI threshold was 35.1% for the Lysholm score and 46.7% for the IKDC score. A longer time from injury to surgery reduced the odds of achieving the MOI threshold for the Lysholm score (odds ratio [OR] per time bracket = 0.7114, p < 0.0001) and IKDC score (OR = 0.8038, p = 0.0003). Male sex was associated with higher odds of achieving the MOI threshold for the IKDC score (OR = 1.9645, p = 0.0143). For patients with chronicity of ≤6 months, the MOI threshold was 35.1% for the Lysholm score and 57.9% for the IKDC score, and for patients with chronicity of >6 months, the thresholds were 24.5% and 27.1%, respectively. The calculated MOI thresholds for the Lysholm and IKDC scores at mid-term follow-up after primary ACLR were 35.1% and 46.7%, respectively. Greater chronicity of the ACL injury was associated with lower odds of achieving the MOI thresholds for the PROMs at mid-term follow-up. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Rate and Timing of Revision and Contralateral Anterior Cruciate Ligament Reconstruction Relative to Index Surgery.

After anterior cruciate ligament (ACL) reconstruction (ACLR), ipsilateral ACL graft reinjury or contralateral ACL injury has been reported. The rate and predictors of such subsequent ACL injuries have not been reported in recent years and in large patient cohorts. The current study utilized a large, national, multi-insurance, administrative database to assess subsequent ACLR and factors associated with its occurrence. Cross-sectional study; Level of evidence, 3. Using the PearlDiver M151 database, patients who underwent ACLR within the United States between 2015 and 2021 were abstracted. All included patients had ≥3 years of evaluation after initial ACLR. Patients who underwent a subsequent reconstruction (ipsilateral or contralateral) within 3 years were determined and the timing assessed. Using univariable and multivariable logistic regression, the factors associated with having a subsequent ACLR and the factors associated with returning for ipsilateral versus contralateral ACLR were examined. In total, 40,151 patients who underwent initial ACLR during the study period were identified. Of these, subsequent ACLR was performed for 1689 patients (4.2%). These included ipsilateral revision for 1018 (60.3%) and contralateral reconstruction for 671 (39.7%) patients. Patients returning for ipsilateral reconstruction did so sooner than patients needing a contralateral reconstruction. On multivariable analysis, the only factor independently associated with subsequent ACLR was younger age (odds ratio [OR] = 4.17 for 10-14 years relative to 25-29 years; P < .0001). Factors associated with returning for an ipsilateral revision ACLR as opposed to contralateral ACLR were earlier revision (OR = 1.49 within 1.5 years relative to after 1.5 years; P = .0001) and female sex (OR = 0.62 relative to male sex; P < .0001). The overall rate of requiring a subsequent ACLR was found to be 4.2%, with 60.3% of these being to the ipsilateral ACL. This information may be helpful for evolving injury-prevention programs and patient counseling.

Patient Acceptable Symptom State Thresholds for IKDC-SKF and KOOS at the 10-Year Follow-up After Anterior Cruciate Ligament Injury: A Study From the Delaware-Oslo ACL Cohort.

Clinicians need thresholds for the Patient Acceptable Symptom State (PASS) and Treatment Failure to interpret group-based patient-reported outcome measures after anterior cruciate ligament (ACL) injury. Validated thresholds that are crucial for accurately discerning patient symptom state and facilitating effective interpretation have not been determined for long-term follow-up after ACL injury. To calculate and validate thresholds for PASS and Treatment Failure for the International Knee Documentation Committee Subjective Knee Form (IKDC-SKF) and the Knee injury and Osteoarthritis Outcome Score (KOOS) subscales at the 10-year follow-up after ACL injury. Cohort study; Level of evidence, 3. A total of 163 participants with unilateral ACL injury (treated with reconstruction or rehabilitation alone) from the Delaware-Oslo ACL Cohort were included. Thresholds for PASS were calculated for IKDC-SKF and KOOS subscales using anchor-based predictive modeling and receiver operating characteristic (ROC) analysis. Too few participants had self-reported Treatment Failure to calculate thresholds for that outcome. Nonparametric bootstrapping was used to derive 95% CIs. The criterion validity of the predictive modeling and ROC-derived thresholds were assessed by comparing actual patient-reported PASS outcome with the calculated PASS outcome for each method of calculation and calculating their positive and negative predictive values with respect to the anchor questions. A total of 127 (78%) participants reported satisfactory symptom state. Predictive modeling PASS thresholds (95% CIs) were 76.2 points (72.1-79.4 points) for IKDC-SKF, 85.4 points (80.9-89.2 points) for KOOS Pain, 76.5 points (67.8-84.7 points) for KOOS Symptoms, 93.8 points (90.1-96.9 points) for KOOS activities of daily living, 71.6 points (63.4-77.7 points) for KOOS Sports, and 59.0 points (53.7-63.9 points) for KOOS quality of life (QoL). Predictive modeling thresholds classified 81% to 93% of the participants as having satisfactory symptom state, whereas ROC-derived thresholds classified >50% as unsatisfied. The thresholds for IKDC-SKF, KOOS Sports, and KOOS QoL resulted in the most accurate percentages of PASS among all identified thresholds and therefore demonstrate the highest validity. Predictive modeling provided valid PASS thresholds for IKDC-SKF and KOOS at the 10-year follow-up after ACL injury. The thresholds for IKDC-SKF, KOOS Sports, and KOOS QoL should be used when determining satisfactory outcomes. ROC-derived thresholds result in substantial misclassification rates of the participants who reported satisfactory symptom state.

Return to Work After Anterior Cruciate Ligament Reconstruction: A Systematic Review.

The timing of return to work (RTW) after anterior cruciate ligament (ACL) reconstruction (ACLR) is a less studied milestone compared with return to sports. To systematically review the rate and postoperative timing of RTW after ACLR. Systematic review; Level of evidence, 4. This study was conducted in accordance with the 2020 PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. A literature search was performed in PubMed, Embase, Cochrane, and Ovid databases for clinical studies reporting RTW after ACLR, and 806 studies were identified in August 2022. A quality assessment was performed using the Methodological Index of Nonrandomized Studies (MINORS) grading system. The following data were extracted from studies: study characteristics, cohort demographics, ACLR technique, concomitant meniscal and/or cartilage procedures, preoperative patient-reported outcomes, rates of RTW, and days required for RTW after ACLR. A total of 13 studies met inclusion criteria, totaling 1791 patients (86.4% male). Wide variability was observed in the methodological quality of the assessed studies (MINORS score range, 8-17). Hamstring tendon (HT) autograft was used in 76.8% (n = 1377; mean age, 30.5 years old), allograft in 17.1% (n = 308; mean age, 33.1 years old), the ligament advanced reinforcement system in 2.5% (n = 46; mean age, 33.2 years old), bone-patellar tendon-bone autograft in 2% (n = 36; mean age, 28.5 years old), and quadriceps tendon autograft in 1.3% (n = 24; mean age, 24.1 years old). Among the included patients, 99.1% (n = 1781) reported successful RTW after surgery. The mean time to RTW was 84.2 days (range, 31.4-107.1 days) for HT and 69.5 days (range, 49-56.6 days) for allograft. While data regarding work intensity before and after ACL injury were absent, our study results suggested that patients most often RTW within 90 days of surgery. Patients with allograft ACLR may RTW earlier than patients undergoing ACLR with HT autograft.

Association of Concomitant MRI-Determined Anterolateral Complex Injury With Quantitative Measurements of Altered Rotational Tibiofemoral Position on MRI in Patients With ACL Injury.

Reduced graft failure rates have been reported after anterior cruciate ligament (ACL) reconstruction combined with anterolateral complex (ALC) augmentation. However, the preoperative diagnosis of concomitant ALC injury remains a clinical challenge. To identify the altered rotational tibiofemoral position on magnetic resonance imaging (MRI) in ACL-injured patients with concomitant ALC injury. Cross-sectional study; Level of evidence, 3. Based on the evaluation of ALC abnormalities on MRI scans by experienced surgeons, 123 patients with nonchronic (<3 months) ACL injury confirmed by arthroscopy were included. The patients were divided into 2 groups-an ALC-injured group (n = 57) and an ALC-intact group (n = 66). The altered rotational tibiofemoral position was evaluated and compared by quantitatively measuring internal rotational tibial subluxation (IRTS) and axial internal tibial rotation (ITRa) on MRI. Multivariate logistic regression and receiver operating characteristic (ROC) analyses were performed to identify the factors associated with concomitant MRI-determined ALC injury. The ALC-injured group showed significantly increased IRTS (P < .001), ITRa (P < .001), lateral anterior tibial subluxation (ATS) (P < .001), and global ATS (GATS) (P = .002) compared with the ALC-intact group, while no significant difference in medial ATS (P = .810) was observed. A strong positive correlation was identified between IRTS and ITRa (rP = 0.809; P < .001). Multivariate analyses revealed that IRTS (P < .001) and GATS (P = .016) were associated factors for the presence of concomitant MRI-determined ALC injury. IRTS (area under the curve [AUC] = 0.734) was more strongly associated with the outcome than GATS (AUC = 0.658) in ROC analyses, suggesting a more significant internal rotational subluxation than anterior subluxation of the tibia. An IRTS threshold of 3.1 mm demonstrated a specificity of 84.2% for indicating the presence of concomitant MRI-determined ALC injury. The presence of concomitant MRI-determined ALC injury in ACL-injured patients was associated with a significant increase in IRTS and ITRa compared with those with intact ALC, indicating that these MRI measurements of the altered rotational tibiofemoral position could serve as potential quantifiable indicators for identifying concomitant ALC injury in clinical practice.

Distinct patterns of cytokines, chemokines, and growth factors in synovial fluid after ACL injury in comparison to osteoarthritis.

This study analyzed knee synovial fluid after anterior cruciate ligament (ACL) tear and in osteoarthritis (OA) to test the hypotheses that concentrations of cytokines, chemokines, and growth factors differ (a) by diagnosis and (b) after ACL tear by time from injury and presence/absence of concomitant meniscus tear. Synovial fluid samples were collected from two groups, ACL tears (with or without meniscus tear) (N = 13) and Kellgren-Lawrence grade 3 and 4 OA (N = 16), undergoing clinically indicated aspiration of the knee joint. Multiple cytokines, chemokines, and growth factors were assessed using a multiplexed 45-protein panel. Comparisons were made for the concentrations of all molecules between ACL tear and OA patients, isolated versus combined ACL and meniscus tears, and categorized by time from injury: acute or early subacute (<15 days, N = 8) versus late subacute or chronic (>15 days and <3 months, N = 5). ACL tear patients have higher levels of six molecules (IL-4, IL-5, IL-13, PlGF-1, bNGF, TNF-α) in knee synovial fluid compared to OA patients. Isolated ACL tears express higher levels of IL-4, IL-13 and IFN-γ and lower levels of IL-7 than ACL tears with a concomitant meniscus tear. SDF-1α, PlGF-1, IL-1RA, HGF, bNGF, and BDNF levels are elevated immediately after injury and drop off significantly in the late subacute phase (after 15 days). Synovial fluid from knees with ACL tears have elevated metabolic activity compared to knees with OA. The cytokine profiles after ACL tears are influenced by the time from injury and the presence of meniscus tears. These findings offer valuable insights into the levels of cytokines, chemokines, and growth factors in the knee after ACL injury, information which may have important implications for the diagnosis, prognosis and treatment of this common pathology.

The Role of Artificial Intelligence in Anterior Cruciate Ligament Injuries: Current Concepts and Future Perspectives

The remarkable progress in data aggregation and deep learning algorithms has positioned artificial intelligence (AI) and machine learning (ML) to revolutionize the field of medicine. AI is becoming more and more prevalent in the healthcare sector, and its impact on orthopedic surgery is already evident in several fields. This review aims to examine the literature that explores the comprehensive clinical relevance of AI-based tools utilized before, during, and after anterior cruciate ligament (ACL) reconstruction. The review focuses on current clinical applications and future prospects in preoperative management, encompassing risk prediction and diagnostics; intraoperative tools, specifically navigation, identifying complex anatomic landmarks during surgery; and postoperative applications in terms of postoperative care and rehabilitation. Additionally, AI tools in educational and training settings are presented. Orthopedic surgeons are showing a growing interest in AI, as evidenced by the applications discussed in this review, particularly those related to ACL injury. The exponential increase in studies on AI tools applicable to the management of ACL tears promises a significant future impact in its clinical application, with growing attention from orthopedic surgeons.

Correlation of muscle strength and reported knee function after Anterior Cruciate Ligament (ACL) graft, unrepaired ACL injury, and healthy knees

Correlation of muscle strength and reported knee function after Anterior Cruciate Ligament (ACL) graft, unrepaired ACL injury, and healthy knees

Deep Learning Artificial Intelligence Tool for Automated Radiographic Determination of Posterior Tibial Slope in Patients With ACL Injury.

An increased posterior tibial slope (PTS) corresponds with an increased risk of graft failure after anterior cruciate ligament (ACL) reconstruction (ACLR). Validated methods of manual PTS measurements are subject to potential interobserver variability and can be inefficient on large datasets. To develop a deep learning artificial intelligence technique for automated PTS measurement from standard lateral knee radiographs. It was hypothesized that this deep learning tool would be able to measure the PTS on a high volume of radiographs expeditiously and that these measurements would be similar to previously validated manual measurements. Cohort study (diagnosis); Level of evidence, 2. A deep learning U-Net model was developed on a cohort of 300 postoperative short-leg lateral radiographs from patients who underwent ACLR to segment the tibial shaft, tibial joint surface, and tibial tuberosity. The model was trained via a random split after an 80 to 20 train-validation scheme. Masks for training images were manually segmented, and the model was trained for 400 epochs. An image processing pipeline was then deployed to annotate and measure the PTS using the predicted segmentation masks. Finally, the performance of this combined pipeline was compared with human measurements performed by 2 study personnel using a previously validated manual technique for measuring the PTS on short-leg lateral radiographs on an independent test set consisting of both pre- and postoperative images. The U-Net semantic segmentation model achieved a mean Dice similarity coefficient of 0.885 on the validation cohort. The mean difference between the human-made and computer-vision measurements was 1.92° (σ = 2.81° [P = .24]). Extreme disagreements between the human and machine measurements, as defined by ≥5° differences, occurred <5% of the time. The model was incorporated into a web-based digital application front-end for demonstration purposes, which can measure a single uploaded image in Portable Network Graphics format in a mean time of 5 seconds. We developed an efficient and reliable deep learning computer vision algorithm to automate the PTS measurement on short-leg lateral knee radiographs. This tool, which demonstrated good agreement with human annotations, represents an effective clinical adjunct for measuring the PTS as part of the preoperative assessment of patients with ACL injuries.

A comparison between physical therapy clinics with high and low rehabilitation volumes of patients with ACL reconstruction

BackgroundTreatment volume can impact outcomes after surgical procedures of the knee between surgeons with high- and low-patient-volumes. However, the difference between physical therapeutic clinics with high- and low-volumes has not been widely researched. This registry study aims to investigate how patient volume affects knee function outcomes after anterior cruciate ligament (ACL) reconstruction at physical therapy (PT) clinics in terms of odds for a second ACL injury, return to pre-injury level of activity, perceived knee function, and recovery of strength and hop performance.MethodData were extracted from the Project ACL, a local rehabilitation registry. High- and low-volume clinics were defined based on the number of patients who attended different clinics. High-volume clinics were defined as those with > 100 patient registrations in Project ACL during the study period while low-volume clinics were those with ≤ 100 patient registrations. High- and low-volume clinics were compared, based on muscle function and patient-reported outcomes across 4 follow-ups, 2-, 4-, 8-, and 12 months, during the first year after ACL reconstruction, and odds of second ACL injury up to 2 years after ACL reconstruction.ResultOf the 115 rehabilitation clinics included, 111 were classified as low-volume clinics and included 733 patients, and 4 as high-volume clinics which included 1221 patients. There were 31 (1.6%) second ACL injuries to the ipsilateral or contralateral side within the first 12 months and 68 (4.0%) within 2 years. No difference in the incidence of a second ACL injury, within 12 months follow-up odds ratio (OR) 0.95 [95% CI 0.46–1.97] or within 2 years follow-up OR 1.13 [95% CI 0.68–1.88], was found between high- and low-volume clinics. There were early (2 months) and non-clinically relevant differences in patient-reported outcomes (PROs) and physical activity levels early after ACL reconstruction in favor of high-volume clinics. One year after ACL reconstruction, no differences were observed between high- and low-volume clinics in terms of PROs, muscle function, and return to pre-injury level of activity.ConclusionNo clinically relevant difference in the incidence of secondary ACL injuries in patients who underwent rehabilitation after ACL reconstruction at high- or low-volume physical therapist clinics was found. In addition, no clinically relevant differences in outcomes were found during the first year in terms of patient-reported outcomes, recovery of muscle function, or return to pre-injury level of activity.

Combining return to sport, psychological readiness, body mass, hamstring strength symmetry, and hamstring/quadriceps ratio increases the risk of a second anterior cruciate ligament injury.

To investigate the combinations of variables that comprise the biopsychosocial model domains to identify clinical profiles of risk and protection of second anterior cruciate ligament injury. One hundred and forty-five patients for return-to-sport testing after anterior cruciate ligament (ACL) reconstruction (ACLR) were contacted, and 97 were deemed eligible. All were evaluated between 6 and 24months and followed up for 2years. Participants answered the International Knee Documentation Committee (IKDC) and Anterior Cruciate Ligament-Return to Sport after Injury Scale (ACL-RSI), performed the postural stability assessment using the Biodex Balance System, and assessed muscle strength at 60° and 300°/s on the isokinetic dynamometer. Personal factors (age, gender, body mass index), body structures (graft type and concomitant injuries), and environmental factors (time between surgery and evaluation) were also collected. The participants were asked about the occurrence of a second ACL injury and return to sport after 2years of follow-up. Classification and regression tree (CART) analysis was used to determine predictors of a second ACL injury. The receiver operating characteristic (ROC) curve was performed to verify the accuracy of the CART analysis, in addition to the sensitivity, specificity, and relative risk (RR) of the model. Of the initial 97 participants, 88 (89.8%) responded to follow-up and 14 (15.9%) had a second ACL injury (11 graft ruptures and three contralateral ACL). CART analysis identified the following variables as predictors of second ACL injury: return to sport, hamstring strength symmetry at 300°/s, ACL-RSI score, hamstrings/quadriceps ratio at 60°/s, and body mass index (BMI). CART correctly identified 9 (64.3%) of the 14 participants who were reinjured and 71 (95.9%) of the 74 participants who were not. The total correct classification was 90.9%. The area under the ROC curve was 0.88 (95% CI 0.72-0.99; p < 0.001), and the model showed a sensitivity of 75% (95% CI 42.8-94.5), specificity of 93.4% (95% CI 85.3-97.8), and RR of 15.9 (95% CI 4.9-51.4; p < 0.0001). The combination of hamstring strength symmetry, hamstring/quadriceps ratio (body functions); return to sport (activity and participation); psychological readiness; and BMI (personal factors) could identify three clinical risk profiles for a second ACL injury with good accuracy. IV.

Poster 277: Return to Sport after Multi-Ligament Knee Injury in Young Athletes

Objectives: While return to sport (RTS) has been well studied in young athletes after anterior cruciate ligament (ACL) reconstruction, there is a paucity of literature on RTS following reconstructive surgery for multi-ligament knee injury (MLKI). The purpose of this study is to assess level of RTS following MLKI in athletes 23 years old or younger at the time of injury and evaluate the factors associated with RTS. Methods: This was a retrospective study. We identified 116 patients at our Level 1 referral center who sustained MLKI at an age of 23 years old or younger. All 116 patients underwent operative reconstruction. Patients were contacted via mail and then completed surveys by telephone if willing to participate. Our primary outcome variable was self-reported ability to return to sport at their preoperative level or higher following surgery. Secondary variables included 2000 International Knee Documentation Committee Subjective Form (2000 IKDC-SF), ACL Return to Sport After Injury (ACL-RSI), and Short-Form 12 (SF-12) physical and mental health scales. Dependent variables included age, participation in cutting sports, number of and specific ligaments injured, and any concurrent mental health diagnoses. Results: A total of 30 (25.9%) patients completed surveys at an average follow-up of 7.8 years postoperatively (24 male, 6 female, 18.1±2.5 years old at time of injury). Of this cohort, 90% of patients returned to sport at some level, while 43.3% returned to their preoperative level or higher. Participation in cutting sports was associated with significantly lower rate of RTS at the same level or higher (p=0.017). Higher 2000 IKDC-SF and ACL-RSI scores were associated with significantly higher rate of RTS at the same level or higher (p=0.001 and 0.002, respectively). Patients who participated in higher level of sport preoperatively demonstrated a higher odds ratio (OR) of returning to their same athletic level or higher following MLKI (OR=3.516 [1.034-11.955]; p=0.044). Number of ligaments injured, age at time of injury, concurrent mental health diagnosis, and SF-12 scores were not associated with a statistically significant change in RTS at the same level or higher. Patients with concurrent ACL and MCL injuries trended toward higher rate of RTS at the same level or higher than two- or three-ligament injuries involving the ACL and PCL and/or LCL, but this was not statistically significant (50% vs. 25%, p=0.225). Conclusions: While a high percentage of young athletes return to some level of sport following MLKI, less than half return to their previous level. Those participating in cutting sports were significantly less likely to return to their pre-injury level of sport following MLKI. Participation in higher level of sport preoperatively was associated with a higher OR of return to sport at the same level or higher. Those who returned to the same level or higher reported significantly higher scores on the ACL-RSI and the 2000 IKDC-SF. There was no significant difference in those returning to sport at their previous level or higher based on SF-12 physical or mental scores, number of ligaments injured, presence of a mental health diagnosis, or age at injury. Future studies will focus on larger cohorts and any modifiable variables to obtain a functional return to sport. [Table: see text][Table: see text][Table: see text][Table: see text]

Comparison of Primary Repair of the Anterior Cruciate Ligament and Anterolateral Structures to Reconstruction and Lateral Extra-articular Tenodesis at 2-Year Follow-up

Background: Lateral extra-articular procedures have been effective in reducing graft rupture rates after anterior cruciate ligament (ACL) reconstruction (ACLR), but the evidence supporting their role in ACL repair is sparse. Purpose/Hypothesis: The purpose was to compare clinical and radiological outcomes of ACLR and lateral extra-articular tenodesis (LET) (ACLR+LET) against combined repair of the ACL and anterolateral (AL) structures (ACL+AL Repair). It was hypothesized that patients undergoing ACL+AL Repair would have noninferior clinical and radiological outcomes with respect to International Knee Documentation Committee (IKDC) scores, knee laxity parameters, and magnetic resonance imaging (MRI) characteristics. Furthermore, it was hypothesized that patients undergoing repair would have significantly better Forgotten Joint Score–12 (FJS-12) values and shorter times to return to the preinjury level of sport, without any increase in the rate of ipsilateral second ACL injury. Study Design: Cohort study; Level of evidence, 2. Methods: Consecutive patients evaluated with an acute ACL tear were considered for study eligibility. ACLR+LET was only performed when intraoperative tear characteristics contraindicated ACL repair. Patient-reported outcome measures such as the IKDC score, Lysholm score, and Knee injury and Osteoarthritis Outcome Score (KOOS); reinjury rates; anteroposterior side-to-side laxity difference; and MRI characteristics were reported at a minimum follow-up of 2 years. The noninferiority study was based on the IKDC subjective score; side-to-side anteroposterior laxity difference; and signal-to-noise quotient (SNQ). The noninferiority margins were defined using the existing literature. An a priori sample size calculation was performed using the IKDC subjective score as the primary outcome measure. Results: A total of 100 patients (47 ACLR+LET, 53 ACL+AL Repair) with a mean follow-up of 25.2 months (range, 24-31 months) were enrolled and underwent surgery within 15 days of injury. At the final follow-up, the differences between groups with respect to the IKDC score, anteroposterior side-to-side laxity difference, and SNQ did not exceed noninferiority thresholds. ACL+AL Repair was associated with a shorter time to return to the preinjury level of sport (ACL+AL Repair: mean, 6.4 months; ACLR+LET: mean, 9.5 months; P < .01), better FJS-12 values (ACL+AL Repair: mean, 91.4; ACLR+LET: mean, 97.4; P = .04), and a higher proportion of patients achieving the Patient Acceptable Symptom State (PASS) for the KOOS subdomains studied (Symptoms: 90.2% vs 67.4%, P = .005; Sport and Recreation: 94.1% vs 67.4%, P < .001; Quality of Life: 92.2% vs 73.9%, P = .01). There were no significant differences between groups with respect to ipsilateral second ACL injury rates (ACL+AL Repair group, 3.8% and ACLR+LET group, 2.1% [n = 1]; P = .63). Conclusion: ACL+AL Repair yielded clinical outcomes that were noninferior to (or not significantly different from) ACLR+LET with respect to IKDC subjective, Tegner activity level, and Lysholm scores; knee laxity parameters; graft maturity; and rates of failure and reoperation. However, there were significant advantages of ACL+AL Repair, including a shorter duration of time to return to the preinjury level of sport, better FJS-12 values, and a higher proportion of patients achieving PASS for KOOS subdomains studied (Symptoms, Sport and Recreation, Quality of Life).

Combining Neurocognitive and Functional Tests to Improve Return-to-Sport Decisions Following ACL Reconstruction.

SYNOPSIS: Neuroplasticity after anterior cruciate ligament (ACL) injury alters how the nervous system generates movement and maintains dynamic joint stability. The postinjury neuroplasticity can cause neural compensations that increase reliance on neurocognition. Return-to-sport testing quantifies physical function but fails to detect important neural compensations. To assess for neural compensations in a clinical setting, we recommend evaluating athletes' neurocognitive reliance by augmenting return-to-sport testing with combined neurocognitive and motor dual-task challenges. In this Viewpoint, we (1) share the latest evidence related to ACL injury neuroplasticity and (2) share simple principles and new assessments with preliminary data to improve return-to-sport decisions following ACL reconstruction. J Orthop Sports Phys Ther 2023;53(8):1-5. Epub: 16 May 2023. doi:10.2519/jospt.2023.11489.

Regional Alterations of Macroscopy and Histology in Meniscus in an ACL Transection Rabbit Model

Background: Although meniscal injury is common after anterior cruciate ligament (ACL) injury, the underlying process in different meniscal regions remains unclear. Purpose: To investigate macroscopic and histological alterations in different meniscal regions in an ACL transection (ACLT) rabbit model. Study Design: Controlled laboratory study. Methods: ACLT was performed on New Zealand White rabbits. Both the medial meniscus (MM) and the lateral meniscus (LM) of the ACLT knees were obtained at 8 (n = 6) and 26 (n = 6) weeks postoperatively. MM and LM collected from nonoperated knees were considered 0 weeks (n = 6) postoperatively. Menisci were then divided into posterior, central, and anterior regions for macroscopic (width) and histological (hematoxylin and eosin, safranin O/fast green, collagen type 2 [COL2]) analysis. Results: The macroscopic widths of MM and LM increased and then decreased over 26 weeks postoperatively, with all 3 MM widths at 8 weeks significantly wider than at 0 weeks (posterior: P < .01; central: P < .05; anterior: P < .05). In the MM, chondrocyte-like cell density increased and then decreased postoperatively, whereas in the LM, it decreased and then remained almost unchanged. Cell density was significantly higher in the central MM region at 8 weeks than at 0 weeks (P < .05). Glycosaminoglycan (GAG) and COL2 percentages of MM and LM decreased from 0 to 8 weeks and then returned to nearly normal levels at 26 weeks postoperatively. In the MM, the GAG percentage in the posterior (P < .05) and central (P < .01) regions and the COL2 percentage in the posterior region (P < .05) was significantly lower at 8 weeks than at 0 weeks. Conclusion: After ACLT in rabbit meniscus, the extracellular matrix (ECM) initially decreased and then increased to almost normal. Additionally, there were significant differences in the ECM percentage in the posterior and central regions of the MM in comparison with other meniscal regions between 0 and 8 weeks postoperatively. Clinical Relevance: The results indicate that the time for meniscal injury after ACL injury is important, and attention should be paid to the posterior and central regions of the MM after ACLT.

Predicting readiness for return to sport and performance after anterior cruciate ligament reconstruction rehabilitation.

Determining readiness to return to sport after anterior cruciate ligament (ACL) reconstruction is challenging. To develop models to predict initial (directly after rehabilitation) and sustainable (one year after rehabilitation) return to sport and performance in individuals after ACL reconstruction. We conducted a multicentre, prospective cohort study and included 208 participants. Potential predictors - demographics, pain, effusion, knee extension, muscle strength tests, jump tasks and three sport-specific questionnaires - were measured at the end of rehabilitation and 12 months post discharge from rehabilitation. Four prediction models were developed using backward logistic regression. All models were internally validated by bootstrapping. All 4 models shared 3 predictors: the participant's goal to return to their pre-injury level of sport, the participant's psychological readiness and ACL injury on the non-dominant leg. Another predictor for initial return to sport was no knee valgus, and, for sustainable return to sport, the single-leg side hop. Bootstrapping shrinkage factor was between 0.91 and 0.95, therefore the models' properties were similar before and after internal validation. The areas under the curve of the models ranged from 0.74 to 0.86. Nagelkerke's R2 varied from 0.23 to 0.43 and the Hosmer-Lemeshow test results varied from 2.7 (p=0.95) to 8.2 (p=0.41). Initial and sustainable return to sport and performance after anterior cruciate ligament reconstruction rehabilitation can be easily predicted by the sport goal formulated by the individual, the individual's psychological readiness, and whether the affected leg is the dominant or non-dominant leg.

Development and validation of a clinical prediction model for return to work after arthroscopic anterior crucial ligament reconstruction

BackgroundOccupational reintegration after anterior cruciate ligament (ACL) rupture is an important clinical issue including economic and health-related perspectives. This study aims to develop and validate a clinical prediction model of return to work in patients with ACL reconstruction surgery considering evidence-based clinical, anthropometric and occupational factors. MethodsData of 562 patients with an ACL rupture receiving an arthroscopic ACL reconstruction were used for analysis. A model for the binary outcome of experiencing an inability to work period of less or more than 14 days (model 1), and a model for finding predictor variables that are linearly associated with a continuous longer inability to work period of over 14 days (model 2) was calculated. Pre-operative determinants including patient characteristics and peri-operative factors were used as predictors for both models. ResultsFor model 1, the highest increase in odds was observed for the occupational type of work, followed by injury of the medial collateral ligament together with partial weight bearing. Small protective effects were observed for female sex, meniscal suture and work with light occupational strain. The type of occupational work, together with revision surgery, a longer duration of limited range of motion and the presence of cartilage therapy were risk factors for longer inability to work. Discrimination and calibration statistics were satisfactory in internal validation. ConclusionWithin the framework of clinical consideration, these prediction models will serve as an estimator for patients, their treating physicians and the socioeconomic partners to forecast the individual cost and benefit of ACL injury.

Let’s talk about sex (and gender) after ACL injury: a systematic review and meta-analysis of self-reported activity and knee-related outcomes

ObjectiveInvestigate sex/gender differences in self-reported activity and knee-related outcomes after anterior cruciate ligament (ACL) injury.DesignSystematic review with meta-analysis.Data sourcesSeven databases were searched in December 2021.Eligibility criteriaObservational or interventional studies with...

The pathological technical and tactical movements of a soccer player during return to sport predicts a second anterior cruciate ligament injury

Background: Return to sport after Anterior Cruciate Ligament (ACL) reconstruction remains a difficult decision-making process that is not structured on shared and homogeneous assessments. This greatly elevates the risk factors for second injuries. Objective: Highlight football-specific gestural, pathological, technical-tactical patterns that contribute to new ACL injuries (ipsilateral graft rupture or contralateral rupture of the native ACL). Material and method: For the purpose of this literature review, peer-reviewed and nonpeer-reviewed indexed journals were consulted from 1979 to the present. Studies were identified by searching them on PubMed/MEDLINE databases. The following search terms were used: “second ACL injury,” “cutting maneuver and ACL”, “sidestep cutting technique and ACL” “Valgus knee in sport” “change of direction and ACL injury” “pressing soccer” tackle in soccer”. The literature search was directed, also, to the Gray Literature. Result: An immediate pressing or re-aggression on the adversary, tackle, or cutting maneuver is clinically read as moments of risk factors, injury, or re-injury, for both the ball bearer and the defender. We found how a good deal of literature emphasizes how side-to-side gestural asymmetries, during technical and tactical movements, present during return to sport can elevate risk factors for second ACL injuries. During ball recovery, 4 main game situations have been found to elevate the risk factors of knee capsular ligament injuries: (1) during tactical moments of collective pressing or individual pressure; (2) in the postural rebalancing phase after moments of instability following the kicking of the ball; (3) dysfunctional moments from gestural instability, in landing, after a header in single-pedal support; (4) during a tackle by direct contact or indirect contact on the joint. Conclusion: Residual pathological movement’s side-to-side asymmetries and postural-dysfunctional pictures related to specific gestures after ACL reconstructive surgery are predictive factors of second ipsilateral ACL injury or injury to the contralateral limb. Given, however, the subjective interpretation of movement quality assessments, their relative reliability and validity in the diagnostic and therapeutic use of complex sports gestures, pressing, and cutting maneuvers, during the process of return to sport should be analyzed together and clinical assessments to identify other and consistent predictors of second ACL injuries.

Think outside the box: Incorporating secondary cognitive tasks into return to sport testing after ACL reconstruction.

The optimal set of return to sport (RTS) tests after anterior cruciate ligament (ACL) injury and ACL reconstruction (ACLR) remains elusive. Many athletes fail to pass current RTS test batteries, fail to RTS, or sustain secondary ACL injuries if they do RTS. The purpose of this review is to summarize current literature regarding functional RTS testing after ACLR and to encourage clinicians to have patients "think" (add a secondary cognitive task) outside the "box" (in reference to the box used during the drop vertical jump task) when performing functional RTS tests. We review important criteria for functional tests in RTS testing, including task-specificity and measurability. Firstly, tests should replicate the sport-specific demands the athlete will encounter when they RTS. Many ACL injuries occur when the athlete is performing a dual cognitive-motor task (e.g., attending to an opponent while performing a cutting maneuver). However, most functional RTS tests do not incorporate a secondary cognitive load. Secondly, tests should be measurable, both through the athlete's ability to complete the task safely (through biomechanical analyses) and efficiently (through measures of performance). We highlight and critically examine three examples of functional tests that are commonly used for RTS testing: the drop vertical jump, single-leg hop tests, and cutting tasks. We discuss how biomechanics and performance can be measured during these tasks, including the relationship these variables may have with injury. We then discuss how cognitive demands can be added to these tasks, and how these demands influence both biomechanics and performance. Lastly, we provide clinicians with practical recommendations on how to implement secondary cognitive tasks into functional testing and how to assess athletes' biomechanics and performance.