Evaluation of the Back-in-Action test Battery In Uninjured High School American Football Players.

Background: Return to sport testing is an established routine, especially for athletes who have ruptured their anterior cruciate ligament (ACL). Various tests are performed, often combined in test batteries, such as the Back-in-action (BIA) test battery. Unfortunately, pre-injury performance is often unknown, and only few athletes pass the high demands of these test batteries. Purpose: The aim of the study was to determine the performance of under 18 American football players on the BIA to establish pre-injury sport specific benchmarks for future RTS testing and to compare these values to data from an age-matched reference group. Methods: Fifty-three healthy male American football players underwent a functional assessment using the "Back-in-action" test battery evaluating agility, speed (Parkour-Jumps and Quick-Feet test), balance (using a PC based balance board), and power (Counter-Movement-Jump [CMJ]) as objective measures. Their results were compared with a previously tested reference group (RP) and within the american football players (AF) through three subgroups according to field playing position. Results: Overall, the American football (AF) athletes showed lower balance scores for both legs (AF: 3.71/3.57/3.61; RP: 3.4/3.2/3.2; p<0.002) compared to the reference population (RP). CMJ height and Quick-Feet results were not statistically different (p>0.05), Parkour-Jump times (AF: 8.18/ 8.13 sec.; RP: 5.9/5.9sec.; p<0.001) were significantly slower. Power output in all CMJ's (AF: 46.86/36.94/37.36 W/kg; RP: 43.2/29.5/29 W/kg; p<0.001) was significantly higher than the RP. Passing and running game involved players (G2 & G3) showed significantly better balance scores (G2+G3: 3.36/3.27/3.33; G1: 4.22/4.06/4.10; p<0.001), higher jump height (G2&G3: 38.87/24.02/24.96 cm; G1: 32.03/19.50/18.96 cm; p<0.001) and more watts/kg (G2&G3: 48.83/37.21/37.64 W/kg; G1: 43.95/36.88/36.53 W/kg; p<0.001) compared to blocking players like Linemen (G1) and to the age matched reference population (RP). Conclusion: Only 53% of the healthy athletes would have been cleared for sport using the BIA test criteria, which highlights the challenging passing criteria. Despite significantly greater power measurements, scores of balance and agility were poorer compared to the reference group, especially for linemen. These data may serve as sport and position specific reference for high school American football players, instead of using the non-specific reference group data. Study design: cross-sectional study. Level of evidence: IIb.

Acute traumatic patellar tendon rupture and simultaneous fracture of the tibial tubercle avulsion in a premature soccer player.

Bone-tendon junctions are prone for acute trauma due to its structural weakness, especially in premature males. For the lower limb, the most eminent area is the tibial tubercle apophysis. Osgood Schlatter disease (OSD) due to repetitive trauma or epiphyseal fractures due to one trauma is well described in literature and known in pediatric practice. Traumatic distal patella tendon ruptures on the other hand are a typical injury of the knee extensor mechanism of mature patients in the fourth decade. Here, the very rare condition of fracture of the tibial tubercle apophysis with simultaneous rupture of the distal patellar tendon of a 15 year old soccer player with previous history of OSD is presented including a review of the recent literature.

[Injuries in the First German Inline Skater Hockey League]. / Verletzungen in der 1. Inline-Skaterhockey-Bundesliga.

Inline skater hockey is a sport originating from ice hockey, which is practised in Germany by about 6000 athletes. There are some differences to ice hockey, which lead to a special risk profile of the athletes.All 315 active players of the First German Inline Skater Hockey League in the years 2018 and 2019 were contacted to participate in an online survey. The subjects of the study completed an anonymised 83-item multiple-choice questionnaire about injuries, training frequency, training content, and sports equipment. 178 athletes responded and 116 questionnaires could be analysed (100 men, 8 women, 8 without information/16 goalies, 55 forwards, 44 defenders).The overall injury incidence was 36.98 per 1000 hours. Minor injuries (wounds, bruises, and blunt muscle injuries) most frequently comprised leg injuries (9.4/1000 hours) and arm injuries (7.2/1000 hours). Relevant injuries (fractures, dislocations, and ligamentous injuries) were most common to the foot (2.4/1000 hours) (n=147) and to the head (1.9/1000 hours) (n=140) and knee (1.7/1000 hours) (n=126). Of 76 fractures, 48 (63.2%) resulted from direct or indirect body contact. Goalkeepers suffered more knee injuries compared with field players, while field players sustained more shoulder injuries. Head injuries (fractures, dental injuries, traumatic brain injuries) were significantly more frequent in players without face protection (3.0/1000h vs. 1.8/1000h). Players who did not perform additional fitness training had significantly more relevant injuries. In this group, knee injuries occurred more frequently as well (4.2/1000h vs. 1.3/1000h). The duration of stretching exercises showed a negative correlation with overall injury incidence (0 minutes: 53.5/1000 hours, 1-4 minutes: 55.8/1000 hours, 5-9 minutes: 23.5/1000 hours, ≥10 minutes: 21.5/1000 hours, p<0.05).In particular, mild injuries occurred with a highly significant reduction in frequency if the subjects performed stretching exercises. Inline skater hockey in the First German League is characterised by a high risk of injury, which can be compared with professional ice hockey. Serious injuries are mainly caused by physical contact. Relevant injuries are most common to the head and lower extremity. The implementation of fitness training had a positive influence on the frequency of injuries. In the context of further professionalisation of this sport, these findings can contribute to the prevention of injuries in inline skater hockey.

Do we still need to screen our patients?-Orthopaedic scoring based on motion tracking.

PURPOSE: Orthopaedic scores are essential for the clinical assessment of movement disorders but require an experienced clinician for the manual scoring. Wearable systems are taking root in the medical field and offer a possibility for the convenient collection of motion tracking data. The purpose of this work is to demonstrate the feasibility of automated orthopaedic scorings based on motion tracking data using the Harris Hip Score and the Knee Society Score as examples. METHODS: Seventy-eight patients received a clinical examination and an instrumental gait analysis after hip or knee arthroplasty. Seven hundred forty-four gait features were extracted from each patient's representative gait cycle. For each score, a hierarchical multiple regression analysis was conducted with a subsequent tenfold cross-validation. A data split of 70%/30% was applied for training/testing. RESULTS: Both scores can be reproduced with excellent coefficients of determination R2 for training, testing and cross-validation by applying regression models based on four to six features from instrumental gait analysis as well as the patient-reported parameter 'pain' as an offset factor. CONCLUSION: Computing established orthopaedic scores based on motion tracking data yields an automated evaluation of a joint function at the hip and knee which is suitable for direct clinical interpretation. In combination with novel technologies for wearable data collection, these computations can support healthcare staff with objective and telemedical applicable scorings for a large number of patients without the need for trained clinicians.

Measures of Knee Capability in Handball Players Differ by Age: A Cross Sectional Study.

The return to sport after knee injury is challenging. This is burdensome for sports with a high incidence of injuries, such as team handball. Various tests guide decision making, but often the athlete's preinjury performance of these measures remains unknown. Moreover, objective return-to-sport criteria of a matching population are missing. The purpose of this study was to evaluate objective measures of knee capability in handball depending on players' age. Two hundred sixty-one handball players performed a functional test battery designed to evaluate knee capability after an anterior cruciate ligament injury: two- and one-legged stability analysis, jumps, speed tests, and agility assessments. For age-specific evaluation, athletes were divided into three age groups (16-19; 20-29;≥30 years). Male players showed differences in two and one-legged jumping height (p<0.02) as well as power per body weight (p<0.01) between age groups. Young female players reached better results in two-and one-legged stability. Besides the quick feet test, results of females did not differ between age groups. Functional knee stability in healthy handball players is partly influenced by age, and females show better results in stability and male athletes in power measurements. This aspect should be considered for return to sports testing and underlines the importance of performance measures in athletic testing.

Functionalization of Synthetic Bone Substitutes.

Bone substitutes have been applied to treat osseous defects for a long time. To prevent implant related infection (IRI) and enhance bone healing functionalized biomaterials, antibiotics and osteoinductive substances have been introduced. This study gives an overview of the current available surface-coated bone substitutes and provides an outlook for future perspectives.

Functional Knee Performance Differences in Handball are Depending on Playing Class.

Handball is one of the most traumatic sports. The knee is the most commonly injured joint. To prevent knee injuries, optimal functional knee stability is of great importance. Nevertheless, there is still no consensus about objective criteria for knee function. Depending on playing class, injury rates seem to differ. The purpose of this study was to evaluate knee function in handball depending on playing class and to establish reference data for functional knee stability. 261 handball players (25.1±5.8 years) performed a functional test including two- and one-legged stability assessments, jump tests, speed and agility analysis. Except for balance, differences between playing classes were detected in all tests with superior performance of high-class players (Germany's 1st ("Oberliga") and 2nd ("Verbandsliga") non-elite playing class). High-class players achieved significant better results in jumping height (p≤0.011-0.029), relative power per body weight in the two-legged counter movement jump (p≤0.023) and speed and agility tests (p≤0.001). This study illustrates the relevance of playing class specific screening. Sports and playing class-specific databases will help to identify individual deficits and strengths in order to prevent injury and increase performance. Moreover, objective criteria for return to sports can be established.

Functional knee stability in non-elite handball: balance and jump performance differ based on players' position.

PURPOSE: Despite the great evolvement of sports medicine, there is still a lack of consensus among sports physicians regarding the decision of return to sports after knee injury, especially in non-elite sports. Currently, no sport-specific reference data for an objective reliable evaluation of functional knee stability exist. The purpose of this study was to assess objective measures on knee joint stability from an established test battery in non-elite handball. It was assumed that players' knee stability differs depending on their field position. METHODS: One-hundred and sixty-five non-elite handball players with a mean age of 24.3 ± 5.5 years underwent a test battery including two-legged and one-legged stability tests, two-legged and one-legged counter movement jumps, two-legged plyometric jumps, one-legged speedy jumps, and a quick feed test. RESULTS: Athletes' physical performance differs in terms of field position. Significant differences between handball players of different positions were found in regard to two-legged stability (p < 0.036) and one-legged stability in the dominant leg (p < 0.009). Players of different positions differed in ground contact time of the plyometric jumps (p < 0.017), whereas the other functional tests did not show significant differences. CONCLUSION: This study is first to report differences in functional knee stability of non-elite handball players on the basis of objective data. Significant differences of functional performance were noted, which were in congruence with position-specific demands. These findings demonstrate the importance of position-specific screening and training to prevent injuries. LEVEL OF EVIDENCE: II.

[Functional Knee Stability in Handball: An Indispensable Criterion For Safe Sport]. / Funktionelle Kniestabilität im Handball: Ein unverzichtbares Kriterium für sicheren Sport.

Various studies in recent years have shown that, within ball sports, handball players have a high risk of accidents and injuries. The knee joint is the most frequently injured body region, and ruptures of the anterior cruciate ligament the most common injury to the knee. To prevent consequential damage or recurrent knee injury, good functional stability of the knee is of high importance. Stability not only prevents injuries, but is also crucial for optimising handball-specific movements. Although there are numerous studies on injuries in handball - mostly performed on professional athletes - the field of research focusing on functional knee stability is deficient. This article provides an overview of the current state of research and discusses existing prevention approaches.

Tensiomyography parameters and serum biomarkers after eccentric exercise of the elbow flexors.

PURPOSE: The tensiomyography (TMG) technique is increasingly used to determine muscle contractile properties in exercise and injury management. The present study investigated the informative value of TMG parameters in correlation with commonly used (creatine kinase, CK; myoglobin, Mb) and novel candidate biomarkers of muscle damage (heart-type fatty acid-binding protein, h-FABP; high-mobility group box 1, HMGB1). METHODS: Ten untrained men performed 6 × 10 eccentric contractions of the elbow flexors at 110% of the concentric one repetition maximum. CK, Mb, h-FABP, HMGB1, arm circumference, pain and TMG data, including maximal displacement (Dm) and temporal outcomes as the contraction time (Tc), sustained time (Ts), delay time (Td), and relaxation time (Tr), were assessed pre-exercise, post-exercise, 20 min, 2 h and on the consecutive 3 days post-exercise. RESULTS: CK and h-FABP significantly increased beginning at 24 h, Mb already increased at 2 h (p < 0.05). HMGB1 was only increased immediately post-exercise (p = 0.02). Tc and Td remained unchanged, whereas Ts and Tr were significantly slower beginning at 24 h (p < 0.05). Dm was decreased within the first 24 h and after 72 h (p < 0.01). The % change from pre-exercise correlated for Dm with CK, Mb, and h-FABP the highest at 48 h (r = - 0.95, - 0.87 and - 0.79; p < 0.01) and for h-FABP with CK and Mb the highest at 24 h (r = 0.96 and 0.94, for all p < 0.001). CONCLUSION: This study supports the correlation of TMG parameters with muscle damage markers after eccentric exercise. Therefore, TMG could represent a non-invasive and cost effective alternative to quantify the degree of muscle damage after exercise interventions.

The role of oxidative and nitrosative stress in the pathology of osteoarthritis: Novel candidate biomarkers for quantification of degenerative changes in the knee joint.

Osteoarthritis (OA) is the most frequently diagnosed joint disorder worldwide with increasing prevalence and crucial impact on the quality of life of affected patients through chronic pain, decreasing mobility and invalidity. Although some risk factors, such as age, obesity and previous joint injury are well established, the exact pathogenesis of OA on a cellular and molecular level remains less understood. Today, the role of nitrosative and oxidative stress has not been investigated conclusively in the pathogenesis of OA yet. Therefore, the objective of this study was to identify biological substances for oxidative and nitrosative stress, which mirror the degenerative processes in an osteoarthritic joint. 69 patients suffering from a diagnosed knee pain participated in this study. Based on the orthopedic diagnosis, patients were classified into an osteoarthritis group (OAG, n=24) or in one of two control groups (meniscopathy, CG1, n=11; anterior cruciate ligament rupture, CG2, n=34). Independently from the study protocol, all patients underwent an invasive surgical intervention which was used to collect samples from the synovial membrane, synovial fluid and human serum. Synovial biopsies were analyzed histopathologically for synovitis (Krenn-Score) and immunohistochemically for detection of end products of oxidative (8-isoprostane F2α) and nitrosative (3-nitrotyrosine) stress. Additionally, the fluid samples were analyzed for 8-isoprostane F2α and 3-nitrotyrosine by competitive ELISA method. The analyzation of inflammation in synovial biopsies revealed a slight synovitis in all three investigated groups. Detectable concentrations of 3-nitrotyrosine were reported in all three investigated groups without showing any significant differences between the synovial biopsies, fluid or human serum. In contrast, significant increased concentrations of 8-isoprostane F2α were detected in OAG compared to both control groups. Furthermore, our data showed a significant correlation between the histopathological synovitis and oxidative stress in OAG (r=0.728, P<0.01). There were no significant differences between the concentrations of 8-isoprostane F2α in synovial fluid and human serum. The findings of the current study support the hypothesis that oxidative and nitrosative stress are components of the multi-factory pathophysiological formation of OA. It seems reasonable that an inflammatory process in the synovial membrane triggers the generation of oxidative and nitrosative acting substances which can lead to a further degradation of the articular cartilage. Based on correlations between the observed degree of inflammation and investigated biomarkers, especially 8-isoprostane F2α seems to be a novel candidate biomarker for OA. However, due to the finding that also both control groups showed increased concentrations of selected biomarkers, future studies have to validate the diagnostic potential of these biomarkers in OA and in related conditions of the knee joint.

[Degenerative changes in the hand and wrist in elite MMA fighting - an MRI study in comparison to boxing]. / Degenerative Veränderungen an Hand und Handgelenk bei MMA-Kämpfern ­ Eine MRT Studie im Vergleich zu Boxern.

OBJECTIVE: Mixed martial arts (MMA) is a combination of multiple combat sports. Acute injuries in MMA are well known and have been broadly described. However, there is little knowledge about degenerative changes in the musculoskeletal system. The aim of this study was to investigate the impact of techniques used in MMA on the occurrence of degenerative changes in the hand and wrist in comparison to classical boxing. METHODS: 11 MMA fighters and 10 boxers with chronic wrist pain were clinically examined. Age, weight, years of training, number of fights, level of competition and weekly hours of training were recorded. To determine degenerative changes, an MRI of the symptomatic hand was assessed. RESULTS: Years of training, level of competition and number of fights did not show a significant difference between MMA and boxing fighters (p > 0.05), but MMA fighters showed significantly more hours of training per week (p < 0.001). The MMA fighters had more often and more severe degenerative changes of all examined structures (bone, fibrocartilage, ligaments and tendons), with the category "bone" reaching significance (p = 0.002). CONCLUSION: MMA athletes show significantly greater incidence and degree of degeneration in hand and wrist joints. The exact reasons are still unknown and further research is needed to determine the influence of MMA techniques on the severity of degenerative changes in the hand and wrist.

Wear Kinetics of Highly Cross-Linked and Conventional Polyethylene Are Similar at Medium-term Follow-Up After Primary Total Hip Arthroplasty.

BACKGROUND: Wear debris is a major factor in aseptic loosening of total hip arthroplasty. Ultra high molecular weight polyethylene inlays are known for significant wear, and the following generation, highly cross-linked polyethylene (HCLPE), has shown promising in vitro and short-term in vivo results. This study aimed to investigate wear debris of HCLPE liners with ceramic heads after 9 years to reveal the in vivo wear kinetics of this common bearing combination. METHODS: Fifty-seven patients (72 hips; 46.5 ± 15.5 years; range 16-76 years) who underwent hip arthroplasty with an HCLPE liner (28- or 32-mm Biolox forte ceramic head) were followed up (mean 9.1 ± 2.4 years; range 3.9-13.8 years). Conventional anteroposterior X-rays were analyzed using Hip Analysis Suite software. RESULTS: Volumetric wear had a mean of 38.67 ± 22.09 mm3/year, 333.08 ± 183.93 mm3 overall, and linear wear was 0.063 ± 0.03 mm/year and 0.546 ± 0.27 mm overall. Male patients had a significantly higher wear rate (46.42 ± 27.68 mm3/year) and total wear (400.71 ± 235.21 mm3). Larger femoral heads had a significantly higher wear rate (43.10 ± 23.93 mm3/year) and total wear (364.23 ± 203.68 mm3). Regression analysis showed a significant cubic relationship (R2 = 0.307) with increasing yearly wear after approximately 108 months postoperatively. CONCLUSIONS: HCLPE liners show significant in vivo wear after 9 years. While the total wear compared to ultra high molecular weight polyethylene liners was decreased, the wear kinetics show a comparable course. The increase in wear rate after only 108 months postoperatively is especially alarming. Longer term follow-up is needed to distinguish the long-term superiority of HCLPE liners in polyethylene-ceramic paired hip arthroplasty.

Blood flow restriction training as a prehabilitation concept in total knee arthroplasty: A narrative review about current preoperative interventions and the potential impact of BFR.

Osteoarthritis of the knee is one of the most commonly diagnosed joint ailments and responsible for increased rates of total knee arthroplasty surgeries worldwide. Whereas the surgical approach is able to diminish the perceived knee pain of concerned patients', the postoperative recovery is often accompanied by persistent skeletal muscle dysfunctions and atrophy, which is responsible for functional deficits for up to several years. Recent findings indicate that surgery induced adverse effects on skeletal muscles are largely associated with the use of pneumatic tourniquets, wherefore several studies try to reduce tourniquet use in orthopedic surgery. However, due to comparable incidence of muscle impairment and increased surgical challenge, the most frequently applied surgical technique in TKA is still associated with the use of tourniquets. When attenuating TKA induced adverse effects, the preoperative preparation of patients by specific exercises (called prehabilitation) was able to enhance preoperative overall fitness through associated accelerated recovery. Based on patients' limited functional activity, prehabilitation techniques have to be particularly designed to allow regular adherence. The present paper is based on a narrative review of current literature, and provides a novel hypothesis by which blood flow restriction exercises (BFR) are able to improve patients' compliance to prehabilitation. BFR training is characterized by the application of low-resistance exercise with similar intensities as daily living tasks in association with a suppression of venous blood flow in an extremity, achieving significant morphological and neuromuscular adaptations in skeletal muscles. In addition, preoperative enhancements in muscle health with corresponding benefits in overall fitness, BFR induced molecular alterations could also be able to interfere with TKA induced pathological signaling. Therefore, based on the known major impact of BFR on skeletal muscle physiology, the present paper aims to illustrate the potential beneficial impact of BFR training as a prehabilitation concept to promote patients regular adherence to preoperative exercises and thus achieve an accelerated recovery and increases in patients' satisfaction.

Ischemic Preconditioning Blunts Muscle Damage Responses Induced by Eccentric Exercise.

PURPOSE: Ischemic preconditioning (IPC) is known to reduce muscle damage induced by ischemia and reperfusion injury during surgery. Because of similarities between the pathophysiological formation of ischemia and reperfusion injury and eccentric exercise-induced muscle damage (EIMD), as characterized by an intracellular accumulation of Ca, an increased production of reactive oxygen species, and increased proinflammatory signaling, the purpose of the present study was to investigate whether IPC performed before eccentric exercise may also protect against EIMD. METHODS: Nineteen healthy men were matched to an eccentric-only (ECC; n = 9) or eccentric proceeded by IPC group (IPC + ECC; n = 10). The exercise protocol consisted of bilateral biceps curls (3 × 10 repetitions at 80% of the concentric one-repetition maximum). In IPC + ECC, IPC was applied bilaterally at the upper arms by a tourniquet (200 mm Hg) immediately before the exercise (3 × 5 min of occlusion, separated by 5 min of reperfusion). Creatine kinase (CK), arm circumference, subjective pain (visual analog scale score), and radial displacement (tensiomyography, maximal radial displacement) were assessed before IPC, preexercise, postexercise, and 20 min, 2 h, 24 h, 48 h, and 72 h postexercise. RESULTS: CK differed from baseline only in ECC at 48 h (P < 0.001) and 72 h (P < 0.001) postexercise. After 24, 48, and 72 h, CK was increased in ECC compared with IPC + ECC (between groups: 24 h, P = 0.004; 48 h, P < 0.001; 72 h, P < 0.001). The visual analog scale score was significantly higher in ECC at 24-72 h postexercise when compared with IPC + ECC (between groups: all P values < 0.001). The maximal radial displacement was decreased on all postexercise days in ECC (all P values < 0.001) but remained statistically unchanged in IPC + ECC (between groups: P < 0.01). CONCLUSIONS: These findings indicate that IPC performed before a bout of eccentric exercise of the elbow flexors blunts EIMD and exercise-induced pain while maintaining the contractile properties of the muscle.

Soft-tissue damage during total knee arthroplasty: Focus on tourniquet-induced metabolic and ionic muscle impairment.

PURPOSE: Advantages of tourniquet use in TKA include benefits for surgeons and patients, varying from a bloodless operation site to a reduced intervention time. The time under ischemia and the reperfusion period are crucial phases for affected soft-tissue, most commonly the extensor mechanism. CASE REPORTS: documented its impact on soft-tissue, ranging from necrotic muscle damage to systemic inflammation. Recently, research regarding tourniquet application patterns discuss clinical outcome parameters in the context of soft-tissue damage, excluding the underlying pathophysiological mechanisms. METHODS: This review summarizes the molecular aspects of soft-tissue damage occurring during tourniquet application in TKA with special focus on ischemia/reperfusion injury. Recent meta-analyses and original trials were reviewed for data on muscle damage and are presented. CONCLUSION: Although underlying pathomechanisms are well known and presented, clinical orthopedic research has so far not addressed this issue. In context of physical training, positive effects regarding postoperative recovery might be possible if more attention is paid to prepare involved muscle preoperatively to TKA (prehabilitation).

Mechanisms underpinning protection against eccentric exercise-induced muscle damage by ischemic preconditioning.

Eccentric exercise training is effective for increasing muscle mass and strength, and improving insulin sensitivity and blood lipid profiles. However, potential muscle damage symptoms such as prolonged loss of muscle function and delayed onset of muscle soreness may restrict the use of eccentric exercise, especially in clinical populations. Therefore, strategies to reduce eccentric exercise-induced muscle damage (EIMD) are necessary, and an extensive number of scientific studies have tried to identify potential intervention modalities to perform eccentric exercises without adverse effects. The present paper is based on a narrative review of current literature, and provides a novel hypothesis by which an ischemic preconditioning (IPC) of the extremities may reduce EIMD. IPC consists of an intermittent application of short-time non-lethal ischemia to an extremity (e.g. using a tourniquet) followed by reperfusion and was discovered in clinical settings in an attempt to minimize inflammatory responses induced by ischemia and ischemia-reperfusion-injury (I/R-Injury) during surgery. The present hypothesis is based on morphological and biochemical similarities in the pathophysiology of skeletal muscle damage during clinical surgery and EIMD. Even though the primary origin of stress differs between I/R-Injury and EIMD, subsequent cellular alterations characterized by an intracellular accumulation of Ca2+, an increased production of reactive oxygen species or increased apoptotic signaling are essential elements for both. Moreover, the incipient immune response appears to be similar in I/R-Injury and EIMD, which is indicated by an infiltration of leukocytes into the damaged soft-tissue. Thus far, IPC is considered as a potential intervention strategy in the area of cardiovascular or orthopedic surgery and provides significant impact on soft-tissue protection and downregulation of undesired excessive inflammation induced by I/R-Injury. Based on the known major impact of IPC on skeletal muscle physiology and immunology, the present paper aims to illustrate the potential protective effects of IPC on EIMD by discussing possible underlying mechanisms.

Partially loaded plain radiographic measurement to evaluate rotational alignment in total knee arthroplasty.

PURPOSE: Rotational alignment of prosthetic components after total knee arthroplasty (TKA) is predominantly monitored with computer tomography (CT), for example by relating the anatomical transepicondylar axis (a-TEA) of the native femur to the posterior bicondylar axis of the prosthetic component (PBCA). The purpose of the present study was to portray a reliable, novel plain radiographic method that likewise enables the evaluation of rotational positioning of prosthetic components in TKA. Furthermore, it was intended to evaluate the prosthetic femoro-tibial functional behavior under loaded conditions. METHODS: Modified plain axial radiographs under partial weight bearing (20 kg) were performed in 63 patients (63 knees) after TKA. On the obtained radiographs, all established, relevant anatomic, and prosthetic axis and angles reflecting the rotational position of the femoral (i.e., a-TEA/PBCA angle) and tibial component were detected twice by two independent examiners with an interval of one month. Additionally, in 14 cases with anterior knee pain after surgery, radiographic results were compared to obtained computer tomography images; intraclass coefficients (ICC's) for intra- and inter-rater reliability were calculated. RESULTS: All pre-assigned axis and angles could be identified doubtlessly by both examiners in all investigated knees. For all measurements, ICC's for intra-rater and inter-rater reliability ranged from 0.75 to 0.96. The comparison of the radiographic measurements with corresponding CT results (n = 14) revealed no significant differences (p > 0.05). Rotational alignment of the tibial tray in relation to the native tibial bone was not measurable due to display overlaying. Femoro-tibial behaviour of the prosthetic components under partial loading showed a high variability. CONCLUSION: We were able to establish a new reliable radiographic technique that is able to show the most established and relevant anatomic landmarks and prosthetic axis after TKA to assess the rotational alignment of the prosthetic components in TKA in relation to the distal femur. The evaluation of the femoro-tibal behaviour instead shows a high variability and so far does not allow valid explanatory conclusions.

High incidence of hyponatremia in rowers during a four-week training camp.

PURPOSE: To investigate the incidence of hyponatremia and its relationship to plasma copeptin, a surrogate marker for arginine vasopressin (AVP) during 28 days of high-volume rowing training. METHODS: Thirty rowers from the German junior national team (21 male) were studied during a training camp. Serum sodium ([Na(+)]), osmolality, and copeptin were measured before the beginning of the camp (day 0), and at days 7, 13, 18, 24, and 28. Daily fluid intake, body weight, urine parameters, and training volume were recorded. RESULTS: Seventy percent of the rowers developed hyponatremia at least once. At day 18, training volume and incidence of hyponatremia (43%) were highest. [Na(+)] decreased from 143 ± 9 mmol·L(-1) (day 0) to 135 ± 5 mmol·L(-1) (day 18, P < .01). Hyponatremia was correlated significantly with weight gain compared with the previous day (P < .01). Copeptin decreased from day 0 to 28 (male: 6.7 ± 2.8 to 3.6 ± 1.7 pmol·L(-1); P < .05; female: 4.8 ± 1.1 to 3.2 ± 1.5 pmol·L(-1); P < .05), being only partially suppressed. Relative fluid intake per body surface area increased from day 7 (male: 2.79 ± 0.78 L·m(-2); female: 2.20 ± 0.70 L·m(-2)) to day 28 (3.88 ± 0.69 L·m(2) and 2.65 ± 0.93 L·m(-2); P < .05). No athlete developed symptomatic hyponatremia. CONCLUSION: Prolonged high-volume rowing training can lead to a high incidence of hyponatremia. Overdrinking and inadequate suppression of AVP contribute to its development.