Sexual Dimorphisms in Anterior Cruciate Ligament Injury: A Current Concepts Review

Disparity in anterior cruciate ligament injury management: a case series review across six National Health Service trusts

BACKGROUND

Effective management of anterior cruciate ligament (ACL) injuries requires a comprehensive approach, from initial assessment, through treatment, rehabilitation, and discharge, however no gold standard care pathway exists to help guide clinicians. This case series provides an overview of current ACL injury management processes in six National Health Service (NHS) Trusts.

METHODS

This study utilised a retrospective case series design within six NHS Trusts in the Yorkshire region of the United Kingdom. Using a standard operating procedure, each Trust selected ten consecutive ACL injured patients (≥ 16 years), managed either surgically or non-surgically. Data relating to the patient injury journey, patient and injury characteristics, key pathway events, rehabilitation management, outcome measures, and discharge, were collected. Data was anonymised and analysed using descriptive statistics.

RESULTS

Reviews covered 55 patients, median age 25.5 years, (41 males, 14 females). Median time to specialist assessment from injury was 12 days (Interquartile Range [IQR] 6 to 20 days), with 43 patients managed operatively, and 12 non operatively. The median number of physiotherapy sessions was 21 (IQR 9 to 29.5), with outcome measures being variably used across Trusts. Trusts using patient reported outcome measures (PROMS) consistently with their patients provided more physiotherapy appointments (34.5 and 27) and achieved higher return to sport (RTS) rates. Time from injury to discharge varied with a median of 421 (IQR 249 to 546) days. Discharge criteria were applied inconsistently across Trusts, with 31% of cases not using specific criteria. However, Trusts using standardised discharge criteria showed better RTS outcomes, with 27 (61%) patients successfully returning to sport.

CONCLUSIONS

This case series review highlighted some good practice in initial ACL management across six NHS Trusts in the Yorkshire region. However, from time to MRI diagnosis to discharge, substantial variation in care is observed. Whether treated operatively or non-operatively, for patients aiming to RTS, this was achieved with greater consistency when more physiotherapy appointments were undertaken, outcome measures and PROMs were used, and specific discharge criteria was utilised. Future larger pathway investigation studies incorporating causative and predictive analysis studies on a national scale are required to determine whether similar trends are observed in a wider ACL injured population, which could help to improve national pathways for patients and clinicians working towards ensuring more positive and standardised patient-related ACL injury outcomes.

Use of Hormonal Contraceptives Is Associated With Decreased Incidence of Anterior Cruciate Ligament Injuries Requiring Reconstruction in Female Patients

PURPOSE

To investigate associations between hormonal contraceptive use and female patients who had sustained an anterior cruciate ligament (ACL) injury requiring reconstruction.

METHODS

Deidentified data collected from female patients aged 15 to 35 years between 2011 and 2024 were obtained from the Colorado Health Data Compass database. The study patients were separated into female patients who sustained an ACL injury that was treated by arthroscopic ACL reconstruction and female patients without a history of ACL injury. Among these groups, non-contraceptive users, total hormonal systemic contraceptive users (including oral contraceptive pills [OCPs], implants, rings, injections, and patches), and OCP users (including formulations of norethindrone [NE] only, drospirenone plus ethinyl estradiol (EE), NE plus EE, and norgestimate plus EE) were included in the analysis.

RESULTS

The 2,120,628 female patients in the systemic hormonal contraceptive use group had a lower incidence of ACL injury (0.079%; 95% confidence interval [CI], 0.075%-0.083%) than the 12,766,138 female patients in the non-contraceptive use group (0.12%; 95% CI, 0.118%-0.121%). In addition, the 745,062 female patients in the OCP use group had a lower ACL injury incidence (0.088%; 95% CI, 0.081%-0.095%), suggesting an association between contraceptive use and ACL injury. When data were stratified by 5-year age intervals, the 15- to 19-year-old group showed no difference in the ACL injury incidence between the OCP use group (0.101%; 95% CI, 0.081%-0.125%) and the non-contraceptive use group (0.118%; 95% CI, 0.114%-0.122%), whereas all other age groups showed a lower ACL injury incidence in the OCP use group. All age groups in the systemic hormonal contraceptive use group had a lower ACL injury incidence than the non-contraceptive use group. Additionally, different contraceptive formulations showed a similar injury incidence, with a lower proportion of ACL injuries in NE-only users (0.03%) compared with norgestimate-EE users (0.093%), NE-EE users (0.099%), and drospirenone-EE users (0.096%).

CONCLUSIONS

Systemic hormonal contraceptive use is associated with a lower incidence of ACL injury requiring ACL reconstruction compared with no contraceptive use in female patients aged 15 to 35 years, with a stronger association with progestin-only OCPs. Female patients aged 15 to 19 years showed no difference in the association with the ACL injury incidence between OCP use and no contraceptive use.

LEVEL OF EVIDENCE

Level III, prognostic retrospective comparative study.

Limitations of athlete-exposures as a construct for comparisons of injury rates by gender/sex: a narrative review

High rates of anterior cruciate ligament (ACL) injuries in girls' and women's sports have garnered significant attention from researchers, sport organisations and the media. Gender/sex disparities in ACL injury rates are often estimated using the construct of athlete-exposures (AEs), a widely used measure of exposure time in sports science and epidemiology that is defined as one athlete participating in one practice or competition. In this narrative review, we explain the limitations of AEs as a measure of exposure time and develop a series of conceptual critiques regarding the use of AEs for the purposes of comparing injury rates by gender/sex. We show that the differing training-to-match ratio and average team size between women and men-rooted in persistent gendered inequities in sports participation and professionalisation-may jeopardise the validity of using AEs for cross-gender comparisons and skew gender/sex disparities in ACL injury rates. To avoid bias, we invite researchers interested in gender/sex disparities in injury rates to collect finer-grained data including individual-level AEs disaggregated by training and competition, as well as to appropriately control for team size and training-to-match ratio at the data analysis stage. Any quantitative comparisons of injury rates should also thoroughly contextualise the limitations of AEs, including their inability to capture the potential qualitative differences between women's and men's training and sporting environments that may influence injury rates.

Long-term observation of marrow adipose tissue and trabecular bone in the rat proximal tibial epiphysis after anterior cruciate ligament reconstruction: effects of immobilization and non-weightbearing

Anterior cruciate ligament (ACL) injury and subsequent reconstruction induce marrow adipose tissue (MAT) accumulation accompanied by bone loss. Short-term immobilization or non-weightbearing after ACL reconstruction further promotes MAT accumulation. However, it is unclear if combining immobilization and non-weightbearing synergistically promotes MAT accumulation. Additionally, it is unknown whether MAT increase induced by immobilization or non-weightbearing can be reversed through remobilization or reloading. We aimed to address these questions. ACL-reconstructed rats were divided into four groups: no intervention, immobilization, non-weightbearing, or immobilization plus non-weightbearing. Immobilization and non-weightbearing were applied for 2 weeks, after which all rats were allowed to move unrestricted. Intact rats were used as controls. The marrow adiposity and trabecular bone in the proximal tibia were histologically assessed at 2-, 4-, and 12-weeks post-surgery. ACL reconstruction induced MAT accumulation and trabecular bone loss accompanied by increased osteoclastogenesis. Two weeks of immobilization and non-weightbearing after ACL reconstruction individually promoted MAT accumulation, but the combined use of these interventions had a similar impact on MAT accumulation as either of each intervention. Importantly, the increased MAT induced by immobilization or non-weightbearing did not reverse even after remobilization or reloading. Neither immobilization, non-weightbearing, nor both conditions combined after ACL reconstruction further decreased trabecular bone compared to no intervention. These findings suggest no synergistic effect of immobilization and non-weightbearing on MAT accumulation, and MAT accumulation induced by 2 weeks of both immobilization or non-weightbearing did not decrease even after at least 10 weeks of remobilization or reloading. MAT accumulation due to both immobilization and non-weightbearing did not have negative effects on trabecular bone.

Functional outcome of anterior cruciate ligament reconstruction with hamstring tendon autograft in Indian population: A systematic review and meta-analysis

Background

Anterior cruciate ligament (ACL) injury is a significant orthopedic issue globally with varying success rates among different populations. Better understanding of functional outcome can help design suitable protocols for ACL reconstruction and recovery. This review aims to evaluate the epidemiological trends and functional outcomes of ACLR procedures in India.

Methods

The review was conducted following PRISMA guidelines, by searching in Google Scholar, Pubmed, Web of Science and Science Direct databases in February 2024. The study encompassed patient demographics, and postoperative outcomes in Indian populations upon ACLR using hamstring tendon autografts. Meta-analysis was conducted with RevMan 5.4 using random-effects models. Funnel plots were used to explore publication bias. Subgroup analyses of follow-up terms and age were also performed.

Results

A total of 26 studies were pooled for overall qualitative and quantitative analysis. Sports injuries (52 %) were found to be more common, followed by road traffic accidents (31 %). Injuries were mostly on the right knees (56 %). Functional outcome analysis using Lysholm Knee Scoring Scale (MD 34.74, 95 % CI 31.58 to 37.89), International Knee Documentation Committee (MD 36.74, 95 % CI 32.36 to 41.13), Tegner Activity Scale (MD 0.90, 95 % CI -0.01 to 1.80) revealed statistically significant overall outcome effect. Statistically non-significant differences were found between follow-up to 6 months and follow-up above 6 months as well as with age. However, meta-analysis showed high level of heterogeneity.

Conclusion

ACLR in Indian population is largely successful in restoring functional activity. However, the outcome of this review is limited by the heterogeneity factor. Further, the Indian studies have not focused on factors affecting the outcome. Therefore, future studies in this direction are needed for understanding the clinical success.

Influence of the Menstrual Cycle and Training on the Performance of a Perturbed Single-Leg Squatting Task in Female Collegiate Athletes

Background

Anterior cruciate ligament (ACL) injuries often occur when an athlete experiences an unexpected disruption, or perturbation, during sports. ACL injury rates may also be influenced by the menstrual cycle.

Purpose

To determine whether training adaptations to knee control and muscle activity during a perturbed single-leg squatting (SLS) task depend on menstrual cycle phase in female athletes.

Study Design

Controlled laboratory study.

Methods

A total of 21 healthy female collegiate athletes (current or former [<3 years]) who competed in 9 different sports performed an SLS task in which they attempted to match their knee position (user signal) to a target signal. The protocol consisted of a 9-condition pretest, 5 sets of 3 training trials, and a 9-condition posttest. One perturbation was delivered in each condition by altering the resistance of the device. Sagittal knee control (absolute error between the target signal and user signal) was assessed using a potentiometer. Muscle activity during perturbed squat cycles was normalized to maximal activation and to corresponding muscle activity during unperturbed squat cycles (%unperturbed) within the same test condition. Athletes performed the protocol during a distinct menstrual cycle phase (early follicular [EF], late follicular [LF], midluteal [ML]). Two-way mixed analysis of variance was used to determine the effects of the menstrual cycle and training on knee control and muscle activity during task performance. Venous blood was collected for hormonal analysis, and a series of health questionnaires and anthropometric measures were also assessed to determine differences among the menstrual cycle groups.

Results

After training, athletes demonstrated better knee control during the perturbed squat cycles (lower absolute error, P < .001) and greater soleus feedback responses to the perturbation (%unperturbed, P = .035). Better knee control was demonstrated in the ML phase versus the EF phase during unperturbed and perturbed squat cycles (P < .039 for both). Quadriceps activation was greater in the ML phase compared with the EF and LF phases, both immediately before and after the perturbation (P < .001 for all).

Conclusion

Athletes learned to improve knee control during the perturbed performance regardless of menstrual cycle phase. The best knee control and greatest quadriceps activation during the perturbed squatting task was found in the ML phase.

Clinical Relevance

These findings may correspond to a lower incidence of ACL injury in the luteal phase and alterations in exercise performance across the menstrual cycle.

Functional knee brace use for 21 h leads to a longer duration to achieve peak vertical ground reaction forces and the removal of the brace after 17.5 h results in faster loading of the knee joint

PURPOSE

To investigate the landing strategies used after discontinuing and continuing the use of a functional knee brace (FKB) while performing a drop jump.

METHODS

Following published methodology and power analysis, 23 uninjured male athletes, mean age of 19.4 ± 3.0 years, performed seven tests, during three test conditions (nonbraced, braced and removed brace or continued brace use), over 6 days of 12 testing sessions (S) for a total of 38.5 h. Each subject was provided with a custom-fitted FKB. This study focuses on the single leg drop jump kinetics during S12 when subjects were randomly selected to remove the FKB after 17.5 h or continued use of FKB. The time to peak vertical ground reaction forces (PVGRF) and PVGRF were recorded on landing in eight trials.

RESULTS

After brace removal, a significantly shorter mean time to PVGRF was recorded (9.4 ± 22.9 msec (3.9%), p = 0.005, 95% confidence interval (95% CI): -168.1, 36.1), while continued brace use required a nonsignificant (n.s.) longer mean duration to achieve PVGRF (19.4 ± 53.6 msec (8.9%), n.s., 95% CI: -49.7, 73.4). No significant mean PVGRF difference was found in brace removal (25.3 ± 65.8 N) and continued brace use (25.1 ± 23.0 N).

CONCLUSION

Removal of FKB after 17.5 h of use led to a significantly shorter time to achieve PVGRF, while continued brace use for 21 h required a longer duration to achieve PVGRF, suggesting faster and slower knee joint loading, respectively. Understanding the concerns associated with the use of FKB and the kinetics of the knee joint will assist clinicians in counselling athletes about the risks and benefits of using an FKB.

LEVEL OF EVIDENCE

Level II.

Investigating and Practicing Orthopedics at the Intersection of Sex and Gender: Understanding the Physiological Basis, Pathology, and Treatment Response of Orthopedic Conditions by Adopting a Gender Lens: A Narrative Overview

In the biomedical field, the differentiation between sex and gender is crucial for enhancing the understanding of human health and personalizing medical treatments, particularly within the domain of orthopedics. This distinction, often overlooked or misunderstood, is vital for dissecting and treating musculoskeletal conditions effectively. This review delves into the sex- and gender-specific physiology of bones, cartilage, ligaments, and tendons, highlighting how hormonal differences impact the musculoskeletal system's structure and function, and exploring the physiopathology of orthopedic conditions from an epidemiological, molecular, and clinical perspective, shedding light on the discrepancies in disease manifestation across sexes. Examples such as the higher rates of deformities (adolescent idiopathic and adult degenerative scoliosis and hallux valgus) in females and osteoporosis in postmenopausal women illustrate the critical role of sex and gender in orthopedic health. Additionally, the review addresses the morbidity-mortality paradox, where women, despite appearing less healthy on frailty indexes, show lower mortality rates, highlighting the complex interplay between biological and social determinants of health. Injuries and chronic orthopedic conditions such osteoarthritis exhibit gender- and sex-specific prevalence and progression patterns, necessitating a nuanced approach to treatment that considers these differences to optimize outcomes. Moreover, the review underscores the importance of recognizing the unique needs of sexual minority and gender-diverse individuals in orthopedic care, emphasizing the impact of gender-affirming hormone therapy on aspects like bone health and perioperative risks. To foster advancements in sex- and gender-specific orthopedics, we advocate for the strategic disaggregation of data by sex and gender and the inclusion of "Sexual Orientation and Gender Identity" (SOGI) data in research and clinical practice. Such measures can enrich clinical insights, ensure tailored patient care, and promote inclusivity within orthopedic treatments, ultimately enhancing the precision and effectiveness of care for diverse patient populations. Integrating sex and gender considerations into orthopedic research and practice is paramount for addressing the complex and varied needs of patients. By embracing this comprehensive approach, orthopedic medicine can move towards more personalized, effective, and inclusive treatment strategies, thereby improving patient outcomes and advancing the field.

Whether Patients with Anterior Cruciate Ligament Reconstruction Walking at a Fast Speed Show more Kinematic Asymmetries?

OBJECTIVE

Knee kinematic asymmetries after anterior cruciate ligament reconstruction (ACLR) are correlated with poor clinical outcomes, such as the progression of knee cartilage degenerations or reinjuries. Fast walking in patients with knee conditions may exacerbate knee kinematic asymmetries, but its impact on ACLR patients is uncertain. The aim of this study is to investigate if fast walking induces more knee kinematic asymmetries in unilateral ACLR patients.

METHODS

This cross-sectional study enrolled 55 patients with unilateral ACLR from January 2020 to July 2022. There were 48 males and seven females with an average age of 30.6 ± 6.4 years. Knee kinematic data were collected at three walking speeds: self-selected, fast (150% normal), and slow (50% normal). A 3D knee kinematic analysis system measured the data, and self-reported outcomes assessed comfort levels during walking. We used SPM1D for two-way repeated ANOVA and posthoc paired t-tests to analyze kinematic differences in groups.

RESULTS

In fast walking, ACLR knees exhibited more transverse kinematic asymmetries than intact knees, including greater external rotation angle (1.8°, 38%-43%; gait cycle [GC], p < 0.05 & 1.8-2.7°, 50%-61% GC, p < 0.05) and increased proximal tibial translation (2.1-2.5 mm, 2%-6% GC, p < 0.05 & 2.5-3.2 mm, 92%-96% GC, p < 0.05). Additionally, ACLR knees showed greater posterior tibial translation than intact knees (3.6-3.7 mm, 7%-8% GC, p < 0.05) during fast walking. No posterior tibial translation asymmetries were observed in slow walking compared to normal walking levels. ACLR knees have the most comfortable feelings in slow walking speed, and the most uncomfortable feelings in fast walking speed levels (29%).

CONCLUSIONS

Fast walking induces additional external tibial rotation and proximal and posterior tibial translation asymmetries in ACLR patients. This raises concerns about long-term safety and health during fast walking. Fast walking, not self-selected speed, is beneficial for identifying postoperative gait asymmetries in ACLR patients.

Internal Rotation Measurement of the Knee with Polymer-Based Capacitive Strain Gauges versus Mechanical Rotation Measurement Taking Gender Differences into Account: A Comparative Analysis

With the conventional mechanical rotation measurement of joints, only static measurements are possible with the patient at rest. In the future, it would be interesting to carry out dynamic rotation measurements, for example, when walking or participating in sports. Therefore, a measurement method with an elastic polymer-based capacitive measuring system was developed and validated. In our system, the measurement setup was comprised of a capacitive strain gauge made from a polymer, which was connected to a flexible printed circuit board. The electronics integrated into the printed circuit board allowed data acquisition and transmission. As the sensor strip was elongated, it caused a change in the spacing between the strain gauge's electrodes, leading to a modification in capacitance. Consequently, this alteration in capacitance enabled the measurement of strain. The measurement system was affixed to the knee by adhering the sensor to the skin in alignment with the anterolateral ligament (ALL), allowing the lower part of the sensor (made of silicone) and the circuit board to be in direct contact with the knee's surface. It is important to note that the sensor should be attached without any prior stretching. To validate the system, an in vivo test was conducted on 10 healthy volunteers. The dorsiflexion of the ankle was set at 2 Nm using a torque meter to eliminate any rotational laxity in the ankle. A strain gauge sensor was affixed to the Gerdii's tubercle along the course of the anterolateral ligament, just beneath the lateral epicondyle of the thigh. In three successive measurements, the internal rotation of the foot and, consequently, the lower leg was quantified with a 2 Nm torque. The alteration in the stretch mark's length was then compared to the measured internal rotation angle using the static measuring device. A statistically significant difference between genders emerged in the internal rotation range of the knee (p = 0.003), with female participants displaying a greater range of rotation compared to their male counterparts. The polymer-based capacitive strain gauge exhibited consistent linearity across all measurements, remaining within the sensor's initial 20% strain range. The comparison between length change and the knee's internal rotation angle revealed a positive correlation (r = 1, p < 0.01). The current study shows that elastic polymer-based capacitive strain gauges are a reliable instrument for the internal rotation measurement of the knee. This will allow dynamic measurements in the future under many different settings. In addition, significant gender differences in the internal rotation angle were seen.

Incidence of injury and illness among paediatric Team USA athletes competing in the 2020 Tokyo and 2022 Beijing Olympic and Paralympic Games

Objective

To describe the incidence of injuries and illnesses among paediatric Team USA athletes competing in the Tokyo 2020 Olympic and Paralympic Games, and the 2022 Beijing Olympic and Paralympic Games.

Methods

An electronic medical record system documented all injuries and illnesses that occurred while competing in the four Games periods. Incidence (IR) with 95% CI per 1000 athlete days were calculated for both injuries and illnesses. Incidence rate ratios (IRR) were calculated to compare injury and illness rates based on age (paediatric vs non-paediatric) sex, Games period and sport type.

Results

Two hundred paediatric athletes (age range, 15-21 years) competed across the four Games periods, representing 16.1% of all Team USA athletes. The overall injury IR (95% CI) was 13.4 (9.8 to 18.1), and the overall illness IR was 5.5 (3.3 to 8.7). There were no differences in incidence between paediatric and non-paediatric athletes for either injury (IRR (95% CI): 0.9 (0.6 to 1.2)) or illness (IRR (95% CI): 0.9 (0.5 to 1.5)). Female paediatric athletes were more likely to sustain an injury compared with male paediatric athletes (IRR (95% CI): 2.4 (1.1 to 5.3)). The most common mechanism of injury was gradual onset (IR, 4.3 (2.3 to 7.2)), and injuries most commonly occurred during practices (IR, 7.0 (4.5 to 10.5)).

Conclusion

Paediatric athletes account for a substantial proportion of Team USA athletes. It is essential that paediatric sports medicine experts are included in the medical team given that paediatric Team USA athletes are just as likely as their adult teammates to sustain an injury or illness.

Digital measurement of anterolateral knee laxity using strain sensors

PURPOSE

The ambition of the research group was to develop a sensor-based system that allowed the transfer of results with strain sensors applied to the knee joint. This system was to be validated in comparison to the current static mechanical measurement system. For this purpose, the internal rotation laxity of the knee joint was measured, as it is relevant for anterolateral knee laxity and anterior cruciate ligament (ACL) injury.

METHODS

This is a noninvasive measurement method using strain sensors which are applied to the skin in the course of the anterolateral ligament. The subjects were placed in supine position. First the left and then the right leg were clinically examined sequentially and documented by means of an examination form. 11 subjects aged 21 to 45 years, 5 women and 6 men were examined. Internal rotation of the lower leg was performed with a torque of 2 Nm at a knee flexion angle of 30°.

RESULTS

Comparison of correlation between length change and internal knee rotation angle showed a strong positive correlation (r = 1, p < 0.01). Whereas females showed a significant higher laxity vs. males (p = 0.003).

CONCLUSIONS

The present study showed that the capacitive strain sensors can be used for reproducible measurement of anterolateral knee laxity. In contrast to the previous static systems, a dynamic measurement will be possible by this method in the future.

Demographic characteristics of patients who underwent anterior cruciate ligament reconstruction at a tertiary care hospital in India

BACKGROUND

Anterior cruciate ligament (ACL) tears are common sports-related injuries. Their incidence is not the same either for all the sports or for the same sport across various nations. This information is maintained by many sports leagues in their registries. However, very few nationwide registries exist for such injuries. This study is carried out to know the demographic characteristics of patients who underwent ACL reconstruction at our hospital in India.

AIM

To know the demographic characteristics of patients who underwent ACL reconstruction at a tertiary care hospital in India.

METHODS

All the patients who underwent ACL reconstruction from January 2020 to December 2021 were retrospectively studied. Patients with multi-ligament injuries or a history of previous knee surgery were excluded. The patients' history was obtained from the hospital records, they were interviewed telephonically, and online questionnaires were given. Their demographic data was analyzed and compared to the existing literature.

RESULTS

A total of 124 patients were operated on for ACL reconstruction during this period. The mean age of the patients was 27.97 years. One hundred and thirteen patients (91.1%) were male and 11 (8.9%) were female. The majority of the patients (47.6%) sustained this injury by road traffic accidents (RTA) followed by sports-related injuries (39.5%). The commonest presenting complaint was giving way of the knee in 118 patients (95.2%). The mean duration from the injury to the first hospital visit among the patients was 290.1 d. The mean duration from the injury to surgery was 421.8 d.

CONCLUSION

ACL patients' demography is different in developing nations as compared to the developed world. RTA are the leading cause of ACL injuries and are followed by recreational sports as a cause. There is delayed access to healthcare leading to delayed diagnosis as well as even greater time to surgery. This, in turn, leads to poorer prognosis and longer rehabilitation. National registries for developing nations are the need of the hour due to the different demographics of ACL injuries in developing countries.

Sex differences in musculoskeletal injury and disease risks across the lifespan: Are there unique subsets of females at higher risk than males for these conditions at distinct stages of the life cycle?

Sex differences have been reported for diseases of the musculoskeletal system (MSK) as well as the risk for injuries to tissues of the MSK system. For females, some of these occur prior to the onset of puberty, following the onset of puberty, and following the onset of menopause. Therefore, they can occur across the lifespan. While some conditions are related to immune dysfunction, others are associated with specific tissues of the MSK more directly. Based on this life spectrum of sex differences in both risk for injury and onset of diseases, a role for sex hormones in the initiation and progression of this risk is somewhat variable. Sex hormone receptor expression and functioning can also vary with life events such as the menstrual cycle in females, with different tissues being affected. Furthermore, some sex hormone receptors can affect gene expression independent of sex hormones and some transitional events such as puberty are accompanied by epigenetic alterations that can further lead to sex differences in MSK gene regulation. Some of the sex differences in injury risk and the post-menopausal disease risk may be "imprinted" in the genomes of females and males during development and sex hormones and their consequences only modulators of such risks later in life as the sex hormone milieu changes. The purpose of this review is to discuss some of the relevant conditions associated with sex differences in risks for loss of MSK tissue integrity across the lifespan, and further discuss several of the implications of their variable relationship with sex hormones, their receptors and life events.

Comparison of two different types of hybrid Tibial fixations for anterior cruciate ligament reconstruction: a prospective comparative cohort study

Background

Previous studies have compared different kinds of fixations for anterior cruciate ligament reconstruction. Nevertheless, there is no optimal method to date. To the best of authors’ knowledge, there is no article discussing the combination of adjustable suspensory device and interference screw for hybrid tibial fixation.

Methods

In total, 66 patients (n = 34, adjustable suspensory device and interference screw; n = 32, cortical screw and interference screw) were analyzed. Their International Knee Documentation Committee score and Tegner activity level scale were evaluated before and after a 2-year follow-up. The Single Assessment Numeric Evaluation score was evaluated after a 2-year follow-up. Physical exams such as range of motion, anterior knee pain (VAS > = 3) and Lachman test were assessed before and at least 12 months after surgery. To evaluate tunnel widening, anteroposterior and lateral view radiography was conducted 1 day and at least 12 months after surgery. A more than 10% change was considered tibial tunnel widening. Mann–Whitney U test, independent t test, paired t test, Fisher’s exact test and chi-squared test were used to compare the variables. Linear and logistic regression models were applied to adjust for potential confounders.

Results

No variable except gender (P = 0.006) showed significant difference with regard to demographic data. After adjustment, there was no statistically significant difference between the groups regarding post-operative physical exams. Patients who used adjustable suspensory device and interference screw had lower post-operative Single Assessment Numeric Evaluation score (adjusted β − 8.194; P = 0.017), Tegner activity level scale (adjusted β − 1.295; P = 0.001) and pre-operative degrees of knee flexion (adjusted β − 2.825; P = 0.026). Less percentage of tunnel widening in the lateral view of radiographs was seen in patients in group of adjustable suspensory device and interference screw (adjusted β − 1.733; P = 0.038). No significant difference was observed in the anteroposterior view of radiographs (adjusted β − 0.667; P = 0.26).

Conclusion

In these 66 patients, we observed less tibial tunnel widening and lower post-operative functional scores in the group of adjustable suspensory device and interference screw. Both groups displayed similar outcomes of physical exams as well as improvement after operation. The proposed method may become an alternative option. Nonetheless, the quality of our study is still limited, and thus further studies are warranted to determine the efficacy and further application.

Trial registration

Joint Institutional Review Board of Taipei Medical University, Taipei, Taiwan (No: N201805094).

Study design

Prospective comparative cohort study; Level of evidence, II.

ACLD patients exhibit additional knee kinematic asymmetries at the speed level of healthy subjects

Anterior cruciate ligament deficiency (ACLD) patients tend to walk slowly but try to catch up with the speed level of healthy subjects daily. Exploring the effects of the walking speed level of healthy subjects on the ACLD patients' knee kinematics is important to improving non-operative treatments and delaying the progression of posttraumatic knee osteoarthritis. This study aimed to explore whether healthy controls' walking speed level leads to additional knee kinematic asymmetries in patients with ACLD. 27 ACLD patients and 29 healthy controls were recruited for the study. The ACLD patients walked at two levels of walking speed, including self-selected and healthy controls' walking speed levels. A three-dimensional gait analysis system was used to collect their knee kinematic data. ACLD patients exhibited more kinematic asymmetries when walking at healthy controls' walking speed level than at their self-selected speeds. The kinematic asymmetries included increased posterior tibial translation (4.6 mm) and anteroposterior tibial ROM (3.9 mm), abduction angle (1.5°), and distal tibial translation (3.2 mm) asymmetries (p < 0.05). Our findings are meaningful for developing non-operative treatment strategies for patients with ACLD. To get fewer knee kinematic asymmetries, self-selected walking speed could be suggested for patients with ACLD daily rather than the speed levels of healthy subjects.