Relationship between hamstring strength and hop performance at 8 and 12 months after ACL reconstruction with hamstring tendon autografts.

BACKGROUND: The relationship between hamstring strength and hop performance after anterior cruciate ligament (ACL) reconstruction with hamstring tendon (HT) autografts has not been well elucidated. The aim was to investigate the relationship between eccentric hamstring strength, assessed with the NordBord, and concentric hamstring strength, assessed with the Biodex, with hop performance at 8 and 12 months after ACL reconstruction. METHODS: Registry study. Patients ≥ 16 years who had undergone primary ACL reconstruction with HT autograft, followed by muscle strength and hop tests at 8 and 12 months were included. Correlations of the relative hamstring strength (Nm/kg or N/kg) and limb symmetry index (LSI) with hop performance were analyzed. Pearson's correlation coefficient, and coefficient of determination (r2) were used for statistical analysis. RESULTS: A total of 90 patients were included, of which 48 (53%) were women. The mean age at ACL reconstruction was 27.0 ± 8.0 years. Relative hamstring strength had significant positive correlations with hop performance, ranging from r = 0.25-0.66, whereas hamstring strength LSI had significant positive correlations which ranged from r = 0.22-0.37 at 8 and 12 months after ACL reconstruction. At 12 months, the relative hamstring strength in the Biodex explained 32.5-43.6% of the hop performance in vertical hop height, hop for distance relative to height, and the total number of side hops, whereas the relative hamstring strength in the NordBord explained 15.2-23.0% of the hop performance. CONCLUSION: The relative hamstring strength in the Biodex test explained 32.5-43.6% of the hop performance, whereas the relative hamstring strength in the NordBord explained 15.2-23.0%. Thus, our findings suggest that relative hamstring strength, especially in the hip-flexed position may be a better indicator of hop performance at 8 and 12 months after ACL reconstruction in patients treated with HT autograft.

Measurement properties of the Swedish version of the anterior cruciate ligament return to sport after injury scale (ACL-RSI): A Rasch analysis.

Purpose: This study aimed to investigate the measurement properties, according to the Rasch Measurement Theory, of the anterior cruciate ligament return to sport after injury scale (ACL-RSI) in patients treated with ACL reconstruction in Sweden. Methods: ACL-RSI responses from 1065 patients treated with ACL reconstruction were extracted from a rehabilitation-specific registry. Rasch analyses were performed on ACL-RSI item response data using the RUMM2030plus software. The analyses focused on targeting (person-item threshold distribution), item hierarchy, response category thresholds, overall and individual item and person fit, differential item functioning (DIF), unidimensionality and reliability. Results: The ACL-RSI had compromised fit to the Rasch model, including DIF and malfunctioning response categories. Several items correlate with each other and the presumptions to aggregate item responses into one single score were not met. When accounting for local dependency, the measurement properties of the ACL-RSI improved in terms of model fit and DIF and unidimensionality were supported. Conclusion: The ACL-RSI was found to have signs of multidimensionality and local dependency, that is, the answers to one item are influenced by the answers to other items. As such, researchers should be careful when using the ACL-RSI as one single score to evaluate patients treated with ACL reconstruction, unless local dependency is accounted for in the scoring process. Level of Evidence: Level III.

Shedding light on the non-operative treatment of the forgotten side of the knee: rehabilitation of medial collateral ligament injuries-a systematic review.

Objective: The purpose of this study was to review the current literature regarding the non-operative treatment of isolated medial collateral ligament (MCL) injuries. Design: Systematic review, registered in the Open Science Framework (https://doi.org/10.17605/OSF.IO/E9CP4). Data sources: The Embase, MEDLINE and PEDro databases were searched; last search was performed on December 2023. Eligibility criteria: Peer-reviewed original reports from studies that included information about individuals who sustained an isolated MCL injury with non-surgical treatment as an intervention, or reports comparing surgical with non-surgical treatment were eligible for inclusion. Included reports were synthesised qualitatively. Risk of bias was assessed with the Risk of Bias Assessment tool for Non-randomized Studies. Certainty of evidence was determined using the Grading of Recommendations Assessment Development and Evaluation. Results: A total of 26 reports (1912 patients) were included, of which 18 were published before the year 2000 and 8 after. No differences in non-operative treatment were reported between grade I and II injuries, where immediate weight bearing and ambulation were tolerated, and rehabilitation comprised different types of strengthening exercises with poorly reported details. Some reports used immobilisation with a brace as a treatment method, while others did not use any equipment. The use of a brace and duration of use was inconsistently reported. Conclusion: There is substantial heterogeneity and lack of detail regarding the non-operative treatment of isolated MCL injuries. This should prompt researchers and clinicians to produce high-quality evidence studies on the promising non-operative treatment of isolated MCL injuries to aid in decision-making and guide rehabilitation after MCL injury. Level of evidence: Level I, systematic review.

A practical guide to the implementation of artificial intelligence in orthopaedic research-Part 2: A technical introduction.

Recent advances in artificial intelligence (AI) present a broad range of possibilities in medical research. However, orthopaedic researchers aiming to participate in research projects implementing AI-based techniques require a sound understanding of the technical fundamentals of this rapidly developing field. Initial sections of this technical primer provide an overview of the general and the more detailed taxonomy of AI methods. Researchers are presented with the technical basics of the most frequently performed machine learning (ML) tasks, such as classification, regression, clustering and dimensionality reduction. Additionally, the spectrum of supervision in ML including the domains of supervised, unsupervised, semisupervised and self-supervised learning will be explored. Recent advances in neural networks (NNs) and deep learning (DL) architectures have rendered them essential tools for the analysis of complex medical data, which warrants a rudimentary technical introduction to orthopaedic researchers. Furthermore, the capability of natural language processing (NLP) to interpret patterns in human language is discussed and may offer several potential applications in medical text classification, patient sentiment analysis and clinical decision support. The technical discussion concludes with the transformative potential of generative AI and large language models (LLMs) on AI research. Consequently, this second article of the series aims to equip orthopaedic researchers with the fundamental technical knowledge required to engage in interdisciplinary collaboration in AI-driven orthopaedic research. Level of Evidence: Level IV.

Rehabilitation and Return to Sport After Anterior Cruciate Ligament Reconstruction.

Rehabilitation after an anterior cruciate ligament (ACL) reconstruction requires patience, devotion, and discipline. Rehabilitation should be individualized to each patient's specific need and sport. Return to sport is a continuum throughout the rehabilitation, and patients should not return to performance before passing a battery of muscle function tests and patient-reported outcomes, as well as change of direction-specific tests. Return to full participation should be an agreement between the patient, physical therapist, surgeon, and coach. For minimal risk for second ACL injury, patients should continue with maintenance and prevention training even after returning to sport.

Wrestling with a ghost: facing an opponent I can neither see nor clinch - the experience of professional wrestlers who have suffered an ACL injury.

This study explored professional wrestlers' experiences of the consequences of an anterior cruciate ligament (ACL) injury and their perception of whether the ACL injury could have been prevented. We interviewed 10 professional wrestlers (60% women, age range 21-34) treated with ACL reconstruction with semistructured interviews. Transcripts were analysed using qualitative content analysis: One major theme, 'Wrestling with a ghost: facing an opponent I can neither see nor clinch', supported by five main categories, emerged from the collected data. The five main categories were: My ACL injury: bad luck or bad planning?; The way back: a fight to return to sport; Only performance counts; The injury's impact on life: a wrestling with emotions; In hindsight, personal growth. Professional wrestlers who experienced an ACL injury expressed that not only the injury itself but also the subsequent recovery posed major challenges that they did not know how to deal with and that, in some cases, ended the athletes' wrestling careers. Professional wrestlers attributed their ACL injuries to bad luck or large training loads and wished that they had more support from the wrestling community when injured.

The NordBord test reveals persistent knee flexor strength asymmetry when assessed two and five years after ACL reconstruction with hamstring tendon autograft.

OBJECTIVE: Comparison of knee flexor strength limb symmetry index (LSI) between the NordBord-test and the Biodex-test, and to determine the relationship between knee flexor strength and function in patients 2 and 5 years after anterior cruciate ligament reconstruction (ACL-R) with hamstring tendon (HT) autografts. DESIGN: Observational registry study. SETTING: Primary care. PATIENTS: Cross-sectional data from 96 patients (55% women) participating in a rehabilitation-registry after ACL-R with HT autografts. MAIN OUTCOME MEASURES: Comparison of knee flexor strength symmetry between the Biodex-test and the NordBord-test. Secondly, the relationship between knee flexor strength test and perceived knee function, activity level, and hop performance. RESULTS: The NordBord-test demonstrated greater strength deficits compared to the Biodex-test with a mean difference of 12.5% ± 15.1% 95 % CI [8.1; 16.9%] at 2 years, and 11.1% ± 11.9% 95 % CI [7.7; 14.6 %] at 5 years after ACL-R. Relative concentric knee flexor strength (Nm/kg) in the Biodex demonstrated significant weak-to-moderate correlations with activity level and hop performance (r = 0.33-0.67) at 2 and 5 years. CONCLUSION: The NordBord-test identified deficits in knee flexor strength LSI not seen with the Biodex-test at 2 and 5 years after ACL-R. No significant correlations were found between the persistent knee flexor strength asymmetry and perceived function, activity level or hop performance.

To achieve the unachievable-Patients' experiences of opting for delayed anterior cruciate ligament reconstruction after trying rehabilitation alone as primary treatment: A qualitative study.

INTRODUCTION: About 50% of patients who sustain an anterior cruciate ligament (ACL) injury are treated without ACL reconstruction (ACL-R). A significant proportion of these patients opt for late ACL-R. Patients' experience of changing treatment has not yet been investigated and presented in the scientific literature. AIM: To explore patients' experiences before and after changing treatment from ACL rehabilitation alone to ACL-R. METHOD: Fifteen patients were interviewed in semi-structured interviews, which were recorded, transcribed, and analyzed with qualitative content analysis, based on the method described by Graneheim and Lundman. Patients were between 26 and 58 years old, and had tried rehabilitation for a minimum of 9 months prior to ACL-R. RESULTS: Two themes, "Expecting what could not be achieved: the struggle to recover and not becoming stable", and "Internal completeness: expectations can be achieved", emerged from the analysis. Each theme was supported by three main categories and 5-6 subcategories. The first theme represents the journey before ACL-R, where patients experienced getting stronger, but perceived the knee as unstable. The second theme represents the journey after ACL-R, where patients expressed that they felt whole after their ACL-R, and where able to achieve their expections. Patients experienced a greater support from the healthcare system, and ultimately expressed a feeling of having achieved the unachievable after ACL-R. SUMMARY: Patients who cross over from ACL rehabilitation to ACL-R experienced rehabilitation alone as insufficient to achieve the desired outcomes, which resulted in a need to opt for delayed ACL-R. Healthcare providers need to support patients, who primarily choose to undergo rehabilitation alone and later opt for ACL-R, throughout the whole rehabilitation process.

Comparison of knee flexor strength recovery between semitendinosus alone versus semitendinosus with gracilis autograft for ACL reconstruction: a systematic review and meta-analysis.

BACKGROUND: Whether there is a difference in harvesting the semitendinosus tendon alone (S) or in combination with the gracilis tendon (SG) for the recovery of knee flexor strength after anterior cruciate ligament (ACL) reconstruction remains inconclusive. Therefore, this study aimed to assess the recovery of knee flexor strength based on the autograft composition, S or SG autograft at 6, 12, and ≥ 24 months after ACL reconstruction. METHODS: A systematic review and meta-analysis was conducted following the PRISMA guidelines. A comprehensive search was performed encompassing the Cochrane Library, Embase, Medline, PEDRo and AMED databases from inception to January 2023. Inclusion criteria were human clinical trials published in English, comprised of randomized controlled trials (RCTs), longitudinal cohort-, cross-sectional and case-control studies that compared knee flexor strength recovery between S and SG autografts in patients undergoing primary ACL reconstruction. Isokinetic peak torques were summarized for angular velocities of 60°/s, 180°/s, and across all angular velocities, assessed at 6, 12, and ≥ 24 months after ACL reconstruction. A random-effects model was used with standardized mean differences and 95% confidence intervals. Risk of bias was assessed with the RoBANS for non-randomized studies and the Cochrane RoB 2 tool for RCTs. Certainty of evidence was appraised using the GRADE working group methodology. RESULTS: Among the 1,227 patients from the 15 included studies, 604 patients received treatment with S autograft (49%), and 623 received SG autograft (51%). Patients treated with S autograft displayed lesser strength deficits at 6 months across all angular velocities d = -0.25, (95% CI -0.40; -0.10, p = 0.001). Beyond 6 months after ACL reconstruction, no significant difference was observed between autograft compositions. CONCLUSION: The harvest of S autograft for ACL reconstruction yields superior knee flexor strength recovery compared to SG autograft 6 months after ACL reconstruction, irrespective of angular velocity at isokinetic testing. However, the clinical significance of the observed difference in knee flexor strength between autograft compositions at 6 months is questionable, given the very low certainty of evidence and small effect size. There was no significant difference in knee flexor strength recovery between autograft compositions beyond 6 months after ACL reconstruction. TRIAL REGISTRATION: CRD42022286773.

No Association Between Hamstrings-to-Quadriceps Strength Ratio and Second ACL Injuries After Accounting for Prognostic Factors: A Cohort Study of 574 Patients After ACL-Reconstruction.

BACKGROUND: The stress on the anterior cruciate ligament (ACL) induced by the quadriceps can be attenuated by activation of the hamstrings by exerting an opposing torque to the anterior translation of tibia. Consequently, considering the ratio between strength of the hamstrings-to-quadriceps (HQ-ratio) may be of value to reduce the odds of second ACL injuries. The objective was therefore to evaluate (1) the association between HQ-ratio and the occurrence of a second ACL injury in patients after ACL-reconstruction within 2 years of return to preinjury sport level and (2) to compare the HQ-ratio between males and females after ACL reconstruction. METHODS: Patients who had undergone primary ACL reconstruction and participated in knee-strenuous activity preinjury were included. Demographics, the occurrence of a second ACL injury, and muscle strength test results before returning to preinjury sport level were extracted from a rehabilitation registry. The endpoint was set at a second ACL injury or 2 years after return to preinjury sport level. A multivariable logistic regression was used to analyze the association between the HQ-ratio and a second ACL injury. RESULTS: A total of 574 patients (50.0% female) with a mean age of 24.0 ± 9.4 years at primary ACL reconstruction were included. In the univariable logistic regression analysis, the odds of sustaining a second ACL injury decreased by 3% for every 1% increase in the HQ-ratio (OR 0.97 [95% CI 0.95-1.00], p = 0.025). After adjusting for the time from reconstruction to return to preinjury sport level, sex, preinjury sport level, graft choice, age, and body mass index, the results were no longer significant (OR 0.98 [95% CI 0.95-1.01], p = 0.16). Females had a higher HQ-ratio compared with males for both the ACL-reconstructed and uninjured side (3.7% [95% CI 5.7; 1.8%], p = 0.0002 and 3.3% [95% CI 4.6; 2.1], p < 0.001, respectively). CONCLUSION: The HQ-ratio did not significantly affect the odds for sustaining a second ACL injury upon return to preinjury sports level after primary ACL reconstruction. Females had a significant higher HQ-ratio than males for both the ACL reconstructed and uninjured side.

Physical symptoms among professional gamers within eSports, a survey study.

BACKGROUND: There is a need to establish the prevalence of self-reported physical symptoms such as pain in professional gamers (PGs) and to analyse whether there are correlations between lifestyle factors and self-reported physical symptoms. The purpose of this study was to analyse the prevalence of self-reported physical symptoms including eye-related problems in PGs. A further aim was to analyse the association between physical symptoms and lifestyle factors such as sleep time, play time and physical activity. METHODS: This study was designed as a cross-sectional study with data based on an electronic survey, created specifically for this study, through discussion and screening of established validated questionnaires for physical symptoms in musculoskeletal conditions: the Karolinska Sleep Questionnaire and the Nordic Musculoskeletal Questionnaire. The survey comprised age and years of experience as a PG as descriptive variables, as well as questions on sleep, play time, physical activity and physical symptoms for the purpose of analysis. The directors of 10 professional gaming corporations were contacted by email with a link to the study-specific survey to distribute to all employees. RESULTS: A total of 40 answers to the electronic survey were retrieved from 40 PGs, of which 62.5% (n = 25) had experienced at least one physical symptom in the three months prior to answering the survey. There was a significant association between playing time and physical symptoms (OR = 8.0; 95% CI 1.4-44.6, p = 0.018), where playing for more than 35 h a week was positively associated with eight times higher odds of experiencing physical symptoms. CONCLUSION: There is a high prevalence of physical symptoms, such as headache and eye symptoms, in professional eSports gamers. There was an association between playing more than 35 h per week with the prevalence of physical symptoms.

Restoring Knee Flexor Strength Symmetry Requires 2 Years After ACL Reconstruction, But Does It Matter for Second ACL Injuries? A Systematic Review and Meta-analysis.

BACKGROUND: It is unknown whether knee flexor strength recovers after anterior cruciate ligament (ACL) reconstruction with a hamstring tendon (HT) autograft and whether persistent knee flexor strength asymmetry is associated to a second ACL injury. OBJECTIVE: We aimed to systematically review (1) whether knee flexor strength recovers after ACL reconstruction with HT autografts, and (2) whether it influences the association with a second ACL injury. A third aim was to summarize the methodology used to assess knee flexor strength. DESIGN: Systematic review and meta-analysis reported according to PRISMA. METHODS: A systematic search was performed using the Cochrane Library, Embase, Medline, PEDRo, and AMED databases from inception to December 2021 and until completion in January 2023. Human clinical trials written in English and conducted as randomized controlled trials, longitudinal cohort, cross-sectional, and case-control studies on patients with index ACL reconstructions with HT autografts harvested from the ipsilateral side were considered. Knee flexor strength was measured isokinetically in both the reconstructed and uninjured limb to enable the calculation of the limb symmetry index (LSI). The Risk of Bias Assessment Tool for Non-Randomized Studies was used to assess risk of bias for non-randomized studies and the revised Cochrane Risk of Bias tool was used for randomized controlled trials. For the meta-analysis, the LSI (mean ± standard error) for concentric knee flexor strength at angular velocities of 60°/second (s) and 180°/s preoperatively and at 3 months, 6 months, 12 months, and 24 months were pooled as weighted means with standard errors. RESULTS: The search yielded 64 studies with a total of 8378 patients, which were included for the assessment of recovery of knee flexor strength LSI, and a total of 610 patients from four studies that investigated the association between knee flexor strength and second ACL injuries. At 1 year after ACL reconstruction, the knee flexor strength LSI had recovered to 89.0% (95% CI 87.3; 90.7%) and 88.3% (95% CI 85.5; 91.1%) for the velocities of 60°/s and 180°/s, respectively. At 2 years, the LSI was 91.7% (95% CI 90.8; 92.6%) and 91.2% (95% CI 88.1; 94.2%), for velocities of 60°/s and 180°/s, respectively. For the association between knee flexor strength and second ACL injuries, there was insufficient and contradictory data. CONCLUSIONS: There was low to very low certainty of evidence indicating that the recovery of knee flexor strength LSI, defined as ≥ 90% of the uninjured side, takes up to 2 years after ACL reconstruction with HT autografts. Whether knee flexor strength deficits influence the association of second ACL injuries is still uncertain. There was considerable heterogeneity in the methodology used for knee flexor strength assessment, which together with the low to very low certainty of evidence, warrants further caution in the interpretation of our results. REGISTRATION NUMBER: CRD42022286773.

Only 10% of Patients With a Concomitant MCL Injury Return to Their Preinjury Level of Sport 1 Year After ACL Reconstruction: A Matched Comparison With Isolated ACL Reconstruction.

BACKGROUND: There is a need for an increased understanding of the way a concomitant medial collateral ligament (MCL) injury may influence outcome after anterior cruciate ligament (ACL) reconstruction. HYPOTHESIS: Patients with a concomitant MCL injury would have inferior clinical outcomes compared with a matched cohort of patients undergoing ACL reconstruction without an MCL injury. STUDY DESIGN: Matched registry-based cohort study; case-control. LEVEL OF EVIDENCE: Level 3. METHODS: Data from the Swedish National Knee Ligament Registry and a local rehabilitation outcome registry were utilized. Patients who had undergone a primary ACL reconstruction with a concomitant nonsurgically treated MCL injury (ACL + MCL group) were matched with patients who had undergone an ACL reconstruction without an MCL injury (ACL group), in a 1:3 ratio. The primary outcome was return to knee-strenuous sport, defined as a Tegner activity scale ≥6, at the 1-year follow-up. In addition, return to preinjury level of sport, muscle function tests, and patient-reported outcomes (PROs) were compared between the groups. RESULTS: The ACL + MCL group comprised 30 patients, matched with 90 patients in the ACL group. At the 1-year follow-up, 14 patients (46.7%) in the ACL + MCL group had return to sport (RTS) compared with 44 patients (48.9%) in the ACL group (P = 0.37). A significantly lower proportion of patients in the ACL + MCL group had returned to their preinjury level of sport compared with the ACL group (10.0% compared with 25.6%, adjusted P = 0.01). No differences were found between the groups across a battery of strength and hop tests or in any of the assessed PROs. The ACL + MCL group reported a mean 1-year ACL-RSI after injury of 59.4 (SD 21.6), whereas the ACL group reported 57.9 (SD 19.4), P = 0.60. CONCLUSION: Patients with a concomitant nonsurgically treated MCL injury did not return to their preinjury level of sport to the same extent as patients without an MCL injury 1 year after ACL reconstruction. However, there was no difference between the groups in terms of return to knee strenuous activity, muscle function, or PROs. CLINICAL RELEVANCE: Patients with a concomitant nonsurgically treated MCL injury may reach outcomes similar to those of patients without an MCL injury 1 year after an ACL reconstruction. However, few patients return to their preinjury level of sport at 1 year.

Comparison of Improvement in Patient-Reported Knee Function After Revision and Multiple-Revision ACL Reconstruction Compared With Primary ACL Reconstruction.

Background: Graft failure after anterior cruciate ligament reconstruction (ACLR) is a debilitating complication often requiring revision surgery. It is widely agreed upon that functional knee outcomes after revision ACLR (r-ACLR) are inferior compared with those after primary reconstruction. However, data are scarce on outcomes after multiple-revision ACLR (mr-ACLR). Purpose: To compare patient-reported knee function in terms of Knee injury and Osteoarthritis Outcome Score (KOOS) preoperatively and 1-year postoperatively after primary ACLR, r-ACLR, and mr-ACLR and evaluate the pre- to postoperative improvement in KOOS scores for each procedure. Study Design: Cohort study; Level of evidence, 3. Methods: Patients from the Swedish National Knee Ligament Registry who underwent their index ACLR between 2005 and 2020 with a minimum age of 15 years at the time of surgery were included in this study. All patients had pre- and postoperative KOOS data. The 1-year postoperative KOOS and the pre- to postoperative changes in KOOS were assessed between patients who underwent primary ACLR and those who underwent subsequent r-ACLR and mr-ACLR. Results: Of 20,542 included patients, 19,769 (96.2%) underwent primary ACLR, 760 (3.7%) underwent r-ACLR, and 13 (0.06%) underwent mr-ACLR. Patients who underwent r-ACLR had significantly smaller pre- to postoperative changes on all KOOS subscales compared with patients undergoing primary ACLR (P < .0001 for all). Furthermore, patients in the mr-ACLR group had significantly smaller changes in the KOOS-Pain subscale compared with patients in the r-ACLR group (-9 ± 23.3 vs 2.5 ± 18; P = .024). Conclusion: The study results indicated that while improvement is seen after primary ACLR, r-ACLR, and mr-ACLR, the greatest improvement in functional outcomes is observed after primary ACLR. Patients who underwent at least 1 r-ACLR, specifically mr-ACLR, had lower postoperative outcome scores, indicating that primary ACLR may provide the best chance for recovery after ACL injury.

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

BACKGROUND: Treatment 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. METHOD: Data 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. RESULT: Of 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. CONCLUSION: No 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.

Physical inactivity 5-8 years after anterior cruciate ligament reconstruction is associated with knee-related self-efficacy and psychological readiness to return to sport.

Objectives: To investigate whether patient demographics and patient-reported outcomes (PROs), respectively, are associated with physical inactivity (PI) 5-8 years after primary anterior cruciate ligament reconstruction (ACLR). Methods: This case control observational study included individuals who had undergone primary ACLR between the ages of 15 and 65 years and had responded to PROs 18 months postoperatively. These individuals were asked to answer a questionnaire regarding their present level of physical activity (PA) at 5-8 years after ACLR. Patient-demographic data and results from the Knee injury and Osteoarthritis Outcome Score, the Knee Self-Efficacy Scale and the ACL Return to Sport (RTS) after Injury scale from 18 months after ACLR were extracted from a rehabilitation-specific register. Univariable logistic regression analyses were performed with PI (<150 min PA per week/≥150 min PA/week) as the dependent variable. Results: Of 292 eligible participants, 173 (47% women; mean±SD age = 31±11 years) responded to the PA questionnaire. In all, 14% (n=25; 28% women) were classified as physically inactive. Participants with lower levels of present and future self-efficacy, OR 1.35 (CI 1.05 to 1.72) and OR 1.20 (CI 1.12 to 1.45), and lower levels of psychological readiness to RTS, OR 1.19 (CI 1 to 1.43), at the 18-month follow-up, had higher odds of being physically inactive 5-8 years after ACLR. None of the patient demographic variables was able to predict PI. Conclusion: Lower levels of knee-related self-efficacy and psychological readiness to RTS, 18 months after ACLR, were associated with PI 5-8 years after surgery.

Greater self-efficacy, psychological readiness and return to sport amongst paediatric patients compared with adolescents and young adults, 8 and 12 months after ACL reconstruction.

PURPOSE: The purpose of this study was to evaluate differences in rehabilitation-specific outcomes between paediatric patients, adolescents and young adults within the first 2 years after anterior cruciate ligament (ACL) reconstruction. A further aim was to determine whether patient age was associated with an increased risk of not achieving symmetrical muscle function within the first 2 years after ACL reconstruction. METHODS: The patient data in the present study were extracted from the rehabilitation outcome registry, Project ACL. Patients aged 11-25 years registered for primary ACL reconstruction with a hamstring tendon autograft between April 1, 2013 and November 23, 2020 were included. A total of 691 patients met the inclusion criteria and were included in the study; 41 paediatric patients (females 11-13, males 11-15 years), 347 adolescents (females 14-19, males 16-19 years) and 303 young adults (females 20-25, males 20-25 years). RESULTS: The comparison between groups revealed that 70% of paediatric patients, 39% of adolescents and 35% of young adults had returned to knee-strenuous sport at 8 months and that 90% of paediatric patients, 71% of adolescents and 62% of young adults had returned to sport at 12 months. Paediatric patients also reported higher scores compared with both the other patient groups on the Knee Self-Efficacy Scale (K-SES) and the Anterior Cruciate Ligament Return to Sport after Injury scale (ACL-RSI) at 8 and 12 months. CONCLUSIONS: A larger proportion of paediatric patients had returned to sport compared with adolescents and young adults 8 and 12 months after ACL reconstruction. Paediatric patients also reported higher self-efficacy and greater psychological readiness to return to sport at 8 and 12 months than the other two groups. No differences in terms of muscle function tests when comparing paediatric patients, adolescents and young adults were found. LEVEL OF EVIDENCE: II.

Effect of Concomitant Lateral Meniscal Management on ACL Reconstruction Revision Rate and Secondary Meniscal and Cartilaginous Injuries.

BACKGROUND: Simultaneous meniscal tears are often present with anterior cruciate ligament (ACL) injuries, and in the acute setting, the lateral meniscus (LM) is more commonly injured than the medial meniscus. PURPOSE: To investigate how a concomitant LM injury, repaired, resected, or left in situ during primary ACL reconstruction (ACLR), affects the ACL revision rate and cartilaginous and meniscal status at the time of revision within 2 years after the primary ACLR. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Data for 31,705 patients with primary ACLR, extracted from the Swedish National Knee Ligament Registry, were used. The odds of revision ACLR, and cartilaginous as well as meniscal injuries at the time of revision ACLR, were assessed between the unexposed comparison group (isolated ACLR) and the exposed groups of interest (ACLR + LM repair, ACLR + LM resection, ACLR + LM repair + LM resection, or ACLR + LM injury left in situ). RESULTS: In total, 719 (2.5%) of the included 29,270 patients with 2 years follow-up data underwent revision ACLR within 2 years after the primary ACLR. No significant difference in revision rate was found between the groups. Patients with concomitant LM repair (OR, 3.56; 95% CI, 1.57-8.10; P = .0024) or LM resection (OR, 1.76; 95% CI, 1.18-2.62; P = .0055) had higher odds of concomitant meniscal injuries (medial or lateral) at the time of revision ACLR than patients undergoing isolated primary ACLR. Additionally, higher odds of concomitant cartilage injuries at the time of revision ACLR were found in patients with LM resection at index ACLR compared with patients undergoing isolated primary ACLR (OR, 1.73; 95% CI, 1.14-2.63; P = .010). CONCLUSION: The results of this study demonstrated higher odds of meniscal and cartilaginous injuries at the time of revision ACLR within 2 years after primary ACLR + LM resection and higher odds of meniscal injury at the time of revision ACLR within 2 years after primary ACLR + LM repair compared with isolated ACLR. Surgeons should be aware of the possibility of concomitant cartilaginous and meniscal injuries at the time of revision ACLR after index ACLR with concomitant LM injury, regardless of the index treatment type received.

No Effect of Return to Sport Test Batteries with and without Psychological PROs on the Risk of a Second ACL Injury: A Critical Assessment of Four Different Test Batteries.

Background: Patients report psychological barriers as important when returning to sport, however, psychological outcome measures are seldom included in return to sport (RTS) assessment. There is a need for clinical trials to integrate psychological patient-reported outcomes (PROs) in return to sport batteries assessing patients treated with ACL reconstruction. Objective: The aim of this study was to determine the association between passing clinical tests of muscle function and psychological PROs and sustaining a second ACL injury in patients who RTS after primary ACL reconstruction. Design: Retrospective Cohort study. Methods: Patients' sex, age, height and weight, and the results of strength and hop tests, as well as answers to PRO's (including Tegner activity scale, the ACL Return to Sport after Injury scale (ACL-RSI) as well as the Quality of Life (QoL) subscale of the Knee injury and Osteoarthritis Outcome Score [KOOS]), were extracted from a rehabilitation-specific registry. Four different test batteries comprising muscle function tests and PROs were created to assess whether patients were ready to RTS. Passing each of the test batteries (yes/no) was used as an independent variable. A multivariable Cox proportional hazard model analysis was performed, with sustaining a second ACL injury (either ipsi- or contralateral; yes/no) within two years of RTS as the dependent variable. Results: A total of 419 patients (male, n=214; 51%) were included, of which 51 (12.2%) suffered a second ACL injury within the first two years after RTS. There were no differences in passing rates in the different RTS test batteries comprising muscle function tests and PROs for patients who suffered a second ACL injury compared to patients who did not. Conclusion: No association between passing the RTS clinical tests batteries comprising muscle function and psychological PROs used, and the risk of a second ACL injury could be found. Level of Evidence: 3©The Author(s).