Sport-related concussion (SRC) is a common and complex injury in athletic populations. Linear head acceleration (LHA) and rotational head acceleration (RHA) are key biomechanical factors believed to contribute to SRC, each through distinct mechanisms. Evaluating head impact magnitudes across different sports, athlete populations, and measurement methods is essential for advancing SRC injury prevention and risk assessment. We aimed to examine linear and rotational head acceleration magnitudes associated with SRC impacts in athletes participating in team sports across all ages and both sexes. We conducted a systematic review and meta-analysis adhering to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. We searched three databases (MEDLINE, Scopus, SPORTDiscus) until 4 September, 2024, and the literature search was updated on the 10 November, 2025. Observational and experimental studies reporting peak LHA and/or RHA during SRC impacts in team sport athletes were included. Data were extracted on study characteristics, instrumentation, and head impact magnitudes. The risk of bias was assessed using the National Institutes of Health Quality Assessment Tool, and the certainty of the evidence was evaluated using GRADE. Random-effects meta-analyses were conducted to compare SRC and non-concussive impacts, and subgroup analyses were performed by sport type, age group, sex, session type, and instrumentation type, reporting standardized mean difference and mean difference. Between-group differences were assessed using Qb statistics, and heterogeneity was evaluated using the I2 statistics. Sensitivity and publication bias analyses were also performed. Data from 30 articles representing 3262 athletes (12

OBJECTIVES:To evaluate the test-retest reliability of a novel laboratory-based protocol for inducing and measuring head acceleration in multiple directions under anticipated and unanticipated conditions. DESIGN:Laboratory-based test-retest reliability study. METHODS:Thirty physically active adults (50% female) completed standardized head perturbations using a custom-built apparatus. Perturbations were applied in flexion, extension, lateral flexion, and rotation under both anticipated (cervical muscle pre-activation) and unanticipated (no cervical pre-activation) conditions across two sessions conducted within one week. Peak linear head acceleration (g) and rotational head acceleration (rad/s2) were recorded using a motion capture system. Reliability was assessed using intraclass correlation coefficients (ICC3,1), standard error of measurement (SEM%), and Bland-Altman plots. RESULTS:For anticipated perturbations, both linear head acceleration and rotational head acceleration demonstrated good to excellent test-retest reliability (intraclass correlation coefficient 0.75-0.90), with SEM% ranging from 3.52% to 8.54%. For unanticipated perturbations, reliability was within the moderate to good range (intraclass correlation coefficient 0.72-0.85), with SEM% ranging from 3.99% to 11.72%. Bland-Altman plots indicated no systematic differences between sessions and no evidence of heteroscedasticity. CONCLUSIONS:Linear and rotational head acceleration showed moderate to excellent reliability across multiple directions and anticipatory conditions, supporting the utility of this laboratory protocol for head impact biomechanics research. Unanticipated perturbations and rotational accelerations were more variable, likely reflecting the complexity of reflexive and asymmetric neuromuscular responses. Together, these findings provide a methodological foundation for future studies on head impact biomechanics and cervical neuromuscular function.

Knee replacement (KR) is the most common osteoarthritis (OA) related surgery. Studies suggest that there are major international and national disparities in pre-operative information, support and access to rehabilitation which have a substantial impact on patients’ perceived outcomes of the KR. The aim of this qualitative study was to explore experiences and perceptions of the care pathway in patients who have undergone KR and subsequent rehabilitation in Sweden. Four focus group discussions were performed including in total 25 patients (16 women), median age 67.5 (range) (46–81 years), 1 to 15 months after KR. The discussion recordings were transcribed verbatim and were analysed qualitatively using content analysis with an inductive approach. The analysis resulted in four categories: (1) The crooked road towards surgery, (2) Needing support throughout the whole journey, (3) Feelings of psychological distress and (4) A balancing act towards a new life. A lack of pre-operative information regarding expected pain, need of support and mental well-being were described. Although the journey was sometimes tough, patients’ expectations were, however, often fulfilled and they were in general satisfied with the decision to undergo surgery. Some of the challenges identified in this study may be alleviated by sufficient pre-operative information covering realistic expectations on surgery outcomes and mental aspects as well as emphatic and holistic support by healthcare providers. The result of this study will aid in the development and implementation of a national clinical practice guideline to ensure patient-centered care throughout the KR care pathway.

Purpose (the aim of the study): To compare individual and clinical characteristics of individuals with knee OA, with or without prior knee surgery.

Objective: To describe the SHIELD cohort in terms of symptoms indicative of early knee osteoarthritis (OA) and to investigate associations between patient characteristics (demographics, activity/injury-related) and these symptoms at 1 (cross-sectional) and 3 years (longitudinal) post anterior cruciate ligament reconstruction (ACLR). Method: 106 participants (50 % women, mean [SD] age 25 [5] years) were included. Symptoms indicative of early knee OA were evaluated by the Knee injury and Osteoarthritis Outcome Score (KOOS) subscale pain, KOOS subscale pain <= 72 (KOOSpain <= 72), and <= 85 on two out of four KOOS subscales (pain, symptoms, activity of daily living, quality of life) (modified Luyten). Results: Mean (SD) KOOS pain scores were 83.2 (15.7) and 87.3 (12.7) at 1 and 3 years, respectively. At 1 year and 3 years post ACLR, 18/101 (18 %) and 14/86 (16 %) participants met the KOOSpain <= 72 criterion, whereas 83/101 (82 %) and 67/86 (78 %) met the modified Luyten criterion. 7/15 (47 %) (KOOSpain <= 72) and 59/70 (84 %) (modified Luyten) classified as having knee OA symptoms 1 year post ACLR were still classified as having OA symptoms after 3 years. Lower activity level at 1 year was the sole variable consistently associated with all three outcomes 3 years post ACLR. Conclusion: The proportion of participants fulfilling existing classification criteria for symptoms indicative of early OA after ACLR is highly dependent on the criteria applied and different criteria seem to capture varying aspects of early OA symptoms. Future studies will reveal if these symptoms will persist long-term or just reflect more transient issues.

BACKGROUND:There is limited knowledge on whether prior knee surgery impacts the clinical profile and treatment outcomes for individuals with knee osteoarthritis (OA). OBJECTIVES:The study aimed to (i) compare individual and clinical characteristics, and (ii) evaluate whether outcomes of first-line treatment differ between individuals with prior knee surgery and those without. METHODS:This study used data from the Swedish Osteoarthritis Register to compare individuals with and without prior knee surgery. Independent t-tests and chi-square tests analyzed characteristics, while linear and logistic regressions assessed group differences at the 3-month follow-up. RESULTS:Of the 94 116 individuals included, 15 637 (17 %) had prior knee surgery. At baseline, those with prior knee surgery were more likely to be male (48 % vs. 29 %), younger (mean age 63 vs. 67 years), and meet physical activity recommendations (69 % vs. 66 %). At the 3-month follow-up, individuals with prior knee surgery had higher odds of expressing willingness to undergo surgery (OR 1.50 [95 % CI, 1.40 to 1.60]), experiencing walking difficulties (OR 1.24 [95 % CI, 1.19 to 1.30]), and to reaching the recommended level of physical activity (OR 1.21 [95 % CI, 1.14 to 1.27]). CONCLUSION:The findings suggest that individuals with knee OA and a history of prior knee surgery may represent a specific clinical phenotype, characterized by a younger age, male sex, and higher levels of physical activity when entering first-line treatment. Despite positive treatment responses in both groups, individuals with a history of surgery more often reported ongoing clinical features at the 3-month follow-up.

Background:Rehabilitation after Knee Replacement (KR) surgery often entails an extensive rehabilitation in primary care but evidence-based high-quality guidelines are lacking. There is also a knowledge gap regarding current rehabilitation modalities applied in primary care in Sweden. This study aimed to (I) describe rehabilitation in primary care after KR and (II) explore physiotherapists' perceptions of patients' challenges during the rehabilitation. Methods:A cross-sectional, web-based survey was conducted among Swedish physiotherapists working in primary care. Questions were categorical or open-ended and related to current rehabilitation practices, treatment modalities, and physiotherapists' perceptions of patients' challenges in rehabilitation after KR. Data were described descriptively and open-ended answers were analyzed with quantitative and qualitative content analysis. Results:In total, 202 physiotherapists answered the survey. Rehabilitation focused on home exercises with recurrent physiotherapy visits. Common treatment modalities were knee range of motion exercises, strength training, and stationary cycling. Key rehabilitation challenges included the following categories: Patients are unprepared, Challenging to find the optimal load, and Restoring function and trust in the knee. Conclusion:Rehabilitation after KR in Swedish primary care seems to be in line with previously recommended international treatment modalities. According to the physiotherapists in this study, some of the key challenges that patients faced were not being prepared for the severe pain regaining function and trust in the knee, balancing load/recovery, and resuming physically demanding activities.

Background: Osteoarthritis (OA) is the most common joint disease. A prior knee injury (with or without surgery) is a risk factor for OA and might represent a specific phenotype in knee OA. However, little is known about whether individuals with knee OA and a history of a prior knee surgery differ in individual and clinical characteristics from individuals with knee OA without a knee surgery. Possible specific characteristics of individuals with knee OA and a prior knee surgery, may promote more patient-centered care decisions in clinical practice. Objectives: To compare individual and clinical characteristics of individuals with knee OA with or without prior knee surgery. Methods: This observational registry-based study includes data from the Swedish Osteoarthritis Register between 2008-2022. The Swedish Osteoarthritis Register contains data about individuals participating in first-line OA treatment (education and exercise) in primary care in Sweden. Individuals with a self-reported prior knee surgery were compared to individuals without a prior knee surgery with regards to individual characteristics (sex, age, BMI) and clinical characteristics (Charnley classification, intake of OA medication, fear of movement, walking difficulties, willingness of surgery, physical activity level, pain, and health-related quality of life) using logistic regression and Odds ratio (OR). Results: The analysis included 77 791 individuals with knee OA of which 13 558 (21 %) reported a prior knee surgery. Individuals with a prior knee surgery had lower odds of being a woman (OR 0.439, 95% CI 0.416 to 0.464) were younger, (OR 0.957, 95% CI 0.954 to 0.959), had a lower BMI (OR 0.966, 95% CI 0.969 to 0.972), and less fear of movement (OR 0.913, 95% CI 0.852 to 0.979) compared to those without prior surgery. On the other hand, those who reported a prior knee surgery had higher odds of being physically active (OR 1.159, 95%CI 1.095 to 1.228), having walking difficulties (OR 1.856, 95%CI 1.744 to 1.975), having a wish for surgery due to OA symptoms (OR 1.856, 95%CI 1.744 to 1.975) and higher health-related quality of life (OR 1.228, 95% CI 1.028 to 1.466). There was no difference between individuals with and without a prior knee surgery for Charnley classification, pain intensity, pain frequency or intake of OA medication. Conclusion: Individuals with knee OA, with and without a prior knee surgery differ in both individual and clinical characteristics. Individuals with knee OA and a prior knee surgery seem to enter first-line treatment at a younger age, with a lower BMI, with less fear of movement, a higher level of physical activity, a higher self-reported health-related quality of life but with more walking difficulties and a higher willingness of surgery. These group differences need to be considered in clinical practice to enhance individualized OA treatment in this group of individuals. REFERENCES: NIL. Acknowledgements: NIL. Disclosure of Interests: None declared.

Objective To estimate patient acceptable symptom state (PASS) and treatment failure (TF) threshold values for Work Productivity and Activity Impairment (WPAI) measure and EQ-5D-5L among people with hip or knee osteoarthritis (OA) 3 and 12 months following participation in a digital self-management intervention (Joint Academy®). Methods Among the participants, we computed work and activity impairments scores (both 0–100, with a higher value reflecting higher impairment) and the Swedish hypothetical- (range: − 0.314 to 1) and experience-based (range: 0.243–0.976) EQ-5D-5L index scores (a higher score indicates better health status) at 3- ( n = 14,607) and 12-month ( n = 2707) follow-ups. Threshold values for PASS and TF were calculated using anchor-based adjusted predictive modeling. We also explored the baseline dependency of threshold values according to pain severity at baseline. Results Around 42.0% and 48.3% of the participants rated their current state as acceptable, while 4.2% and 2.8% considered the treatment had failed at 3 and 12 months, respectively. The 3-month PASS/TF thresholds were 16/29 (work impairment), 26/50 (activity impairment), 0.92/0.77 (hypothetical EQ-5D-5L), and 0.87/0.77 (the experience-based EQ-5D-5L). The thresholds at 12 months were generally comparable to those estimated at 3 months. There were baseline dependencies in PASS/TF thresholds with participants with more severe baseline pain considering poorer (more severe) level of WPAI/EQ-5D-5L as satisfactory. Conclusion PASS and TF threshold values for WPAI and EQ-5D-5L might be useful for meaningful interpretation of these measures among people with OA. The observed baseline dependency of estimated thresholds limits their generalizability and values should be applied with great caution in other settings/populations.

Introduction: Digital options for osteoarthritis (OA) treatment are increasingly available with high patient satisfaction and acceptability. Little is, however, known about physical therapists' (PT) perception of this treatment modality. Objective: To investigate PT's experience of delivering digital treatment for hip and knee OA using a smart-phone application. Method: Nine PTs (mean age 36 years, women n = 5) with 3-24 months experience of delivering digital OA treatment were interviewed using a semi-structured interview guide. The interviews were transcribed verbatim and analyzed using content analysis. Results: Four main categories arose; 1) A feeling of being part of the future, 2) Making an osteoarthritis diagnosis in a digital setting, 3) Facilitators and barriers of digital OA management and 4) Where to go from here? PTs were in general positive for digital treatment delivery but felt that a lack of visual assessments and physical examinations to enhance exercise evaluations and diagnosis accuracy was sometimes a disadvantage. Conclusion: Digital treatment delivery was in general perceived as a time-efficient way of providing high-quality care that may increase patient motivation and adherence without violating the therapeutic alliance. Future implementations of digital OA treatment programs should consider the possibility of including real-time video calls for visual assessment.

Objective: To determine the relative contribution of each of the following aspects: demographics, physical function, and patient-reported outcome measures (PROMs), including both physical and psychological constructs, to return to sport (RTS) (any level) one-year post anterior cruciate ligament reconstruction (ACLR). Design: Cross-sectional cohort study. Methods: We included data for 143 participants (73 women, mean (SD) age 24 (5.8) years) similar to one-year post-ACLR. Data comprised demographics, physical function (hop performance, hip and knee peak torque) and PROMs (Knee Osteoarthritis Outcome Score subscales, perceived stress, and ACL Return to Sport after Injury scale (ACL-RSI)). We then used a Z-normalized multivariable logistic regression model to establish the relative contribution of factors associated with RTS. Results: Sixty-four (45%) of the participants had returned to sport at one year post-ACLR. In the regression model, greater hip abduction peak torque (OR = 1.70, 95% CI; 1.01 to 2.84) and greater psychological readiness to RTS (OR = 2.32, 95% CI; 1.30 to 4.12) were the only variables associated with RTS (R-2 = 0.352). Conclusions: The significant contribution of hip abduction strength and psychological readiness to RTS was still relatively small, suggesting other potential factors explaining RTS which may not be captured by common RTS criteria.

Background and purpose: First-line treatment (education, exercise) for patients with hip and knee osteoarthritis (OA) aims to reduce pain and improve function. We aimed to compare progression to joint replacement within 5 years between responders and non-responders to first-line treatment for hip and knee OA, respectively. Methods: This observational study included data for 30,524 knee OA and 13,787 hip OA patients from the Swedish Osteoarthritis Register, linked with the Swedish Arthroplasty Register, Statistics Sweden, and the Swedish Prescribed Drug Register. The primary prognostic factor was change in pain between baseline and 3-month follow-up, measured on a numeric rating scale (0–10, best to worst) where an improvement of ≥ 2 was classified as responder and ≤ 1 as non-responder. The main outcome was progression to joint replacement surgery within 5 years, assessed using baseline adjusted multivariable Cox regression analyses. Results: At 5 years, in hip OA, 35% (95% confidence interval [CI] 32.2–37.2) of the responders and 48% (CI 45.9–49.5) of the non-responders and in knee OA 14% (CI 13.0–15.3) of the responders and 20% (CI 18.8–20.8) of the non-responders had progressed to joint replacement. Being a responder to the treatment was associated with having a lower probability of progression to surgery for both hip OA (hazard ratio [HR] 0.4, CI 0.4–0.5) and knee OA (HR 0.6, CI 0.5–0.6). Conclusion: Patients with hip or knee OA who experienced pain relief after a first-line OA treatment program were less likely to progress to joint replacement surgery.

Objective To review the efficacy of exercise interventions on sport-related concussion (SRC) incidence, as well as on linear and rotational head accelerations, and isometric neck strength and to assess reporting completeness of exercise interventions using the Consensus on Exercise Reporting Template (CERT).Design Systematic review and meta-analysis, according to the Prisma in Exercise, Rehabilitation, Sport medicine and SporTs science guidelines.Data sources Six databases (MEDLINE, Embase, CINAHL, Scopus, Web of Science CC and SPORTDiscus) were searched up to 26 June 2023.Eligibility criteria for selecting studies Randomised controlled trials (RCTs), cluster RCTs or quasi-experimental studies, evaluating exercise interventions on SRC incidence, linear and rotational head accelerations, and/or isometric neck strength in male and/or female athletes of any age, and/or in a healthy general population.Results A total of 26 articles were included. A large effect size was observed for resistance training (RT) on isometric neck strength (standardised mean difference (SMD) 0.85; 95% CI 0.57 to 1.13; high-quality evidence). Non-significant effect sizes were observed for neuromuscular warm-up programmes on SRC incidence (risk ratio 0.69; 95% CI 0.39 to 1.23; low-quality evidence), or for RT on linear head acceleration (SMD -0.43; 95% CI -1.26 to 0.40; very low-quality evidence) or rotational head acceleration (SMD 0.08; 95% CI -0.61 to 0.77; low-quality evidence). No studies assessed the impact of RT on SRC incidence. CERT scores ranged from 4 to 16 (out of 19) with median score of 11.5 (IQR 9-13).Conclusion RT increases isometric neck strength, but the effect on SRC incidence is unknown. More adequately powered and rigorous trials are needed to evaluate the effect of exercise interventions on SRC incidence, and on linear and rotational head accelerations. Future studies should follow CERT guidelines, as the included interventions were generally not reported in sufficient detail for accurate replication.PROSPERO registration number CRD42023435033.

Purpose (the aim of the study): A history of anterior cruciate ligament (ACL) injury and reconstruction (ACLR) is reported to be associated with a four to six-fold increased risk of developing knee osteoarthritis (OA). Early detection of knee OA is important as this may permit early intervention. Patient-reported pain and other knee symptoms have been suggested as markers indicative of early knee OA. Thus, the aims of the present descriptive study were to investigate 1) the proportion of individuals meeting criteria indicative of early symptomatic knee OA at 1- and 3-years post ACLR and 2) group differences in patient characteristics between participants meeting vs.

AIM:To study the association between within-person changes in patient-reported outcomes (PROMs) and wish for joint surgery during participation in a digital first-line intervention comprising exercise and education for knee/hip osteoarthritis (OA). METHODS:Retrospective observational registry study. Participants enrolled between June 1, 2018 and October 30, 2021, with follow-up data at three months (n = 13,961). We used asymmetric fixed effect (conditional) logistic regressions to study the association between change in wish to undergo surgery at last available time point (3, 6, 9, or 12 months) and improvement or worsening of PROMs pain (0-10), quality of life (QoL) (EQ5D-5L, 0.243-0.976), overall health (0-10), activity impairment (0-10), walking difficulties (yes/no), fear of movement (yes/no), and Knee/Hip injury and Osteoarthritis Outcome Score 12 Items (KOOS-12/HOOS-12, 0-100) function and QoL subscales. RESULTS:The proportion of participants wishing to undergo surgery declined by 2% (95% CI: 1.9, 3.0), from 15.7% at the baseline to 13.3% at 3 months. Generally, improvements in PROMs were associated with reduced likelihood of wishing for surgery, while worsening was associated with increased likelihood. For pain, activity impairment EQ-5D and KOOS/HOOS QoL, a worsening led to a change in the probability of wish for surgery of larger absolute magnitude than an improvement in the same PROM. CONCLUSIONS:Within-person improvements in PROMs are associated with reduced wish for surgery while worsenings with an increased wish for surgery. Larger improvements in PROMs may be needed to match the magnitude of the change in wish for surgery associated with a worsening in the same PROM.

Background: Sports function and psychological readiness to return to sports (RTS) are important outcomes when evaluating rehabilitation after anterior cruciate ligament reconstruction (ACLR). It is, however, unclear which specific factors contribute most to these outcomes. Purpose: To determine associations between demographic characteristics, objective measurements of physical function, patient-reported outcome measure scores, sports-related function assessed with the Knee injury and Osteoarthritis Outcome Score (KOOS) Sport and Recreation subscale, and psychological readiness to RTS assessed with the Anterior Cruciate Ligament–Return to Sport after Injury (ACL-RSI) scale at 1 year after ACLR. Study Design: Cross-sectional study; Level of evidence, 3. Methods: At a mean of 12.5 ± 2.0 months after ACLR, 143 participants (50.3% female), with a mean age of 25.0 ± 5.7 years, were assessed for demographic characteristics, physical factors (hop performance, muscle strength, ankle and hip range of motion), and psychological factors (KOOS Pain and Symptoms subscales, Perceived Stress Scale, fear of reinjury) as well as the KOOS Sport and Recreation subscale and ACL-RSI scale. Backward linear regression models were used to evaluate factors associated with sports function and psychological readiness to RTS. Results: Lower isokinetic knee extension peak torque (limb symmetry index) (B = 18.38 [95% CI, 3.01-33.75]), lower preinjury activity level (B = 2.00 [95% CI, 0.87-3.14]), greater knee pain (B = 0.90 [95% CI, 0.70-1.10]), shorter time between injury and reconstruction (B = 0.16 [95% CI, 0.05-0.26]), and greater fear of reinjury (B = 0.11 [95% CI, 0.01-0.20]) were associated with a worse KOOS Sport and Recreation subscore ( R 2 = 0.683). A shorter hop distance (B = 0.15 [95% CI, 0.00-0.29]) was associated with a lower ACL-RSI score ( R 2 = 0.245). Conclusion: A combination of knee muscle strength, activity level, knee pain, timing of surgery, and fear of reinjury accounted for approximately 70% of the variation in sports function at 1 year after ACLR. In contrast, there was only 1 weak association between physical function and psychological readiness to RTS at this time point. Thus, factors associated with current sports function are much better known than features related to psychological readiness to RTS.