IntroductionIt is recommended to use a tourniquet cuff pressure between 40-80% of the individuals’ arterial occlusion pressure (AOP) during blood flow restriction (BFR) exercise. The AOP is usually determined in one limb for unilateral BFR exercise or in both limbs individually for bilateral BFR exercise. However, given that the tourniquet cuffs are inflated at both limbs simultaneously during bilateral BFR exercises (e.g., cycling, walking, and squat exercise), it is currently not known if the respective AOP also needs to be determined during bilateral tourniquet cuff inflation. Consequently, the present study aimed to compare the AOP during unilateral versus bilateral tourniquet cuff inflation in the lower extremities.MethodsIn a randomized cross-over trial, the AOP of 25 young healthy participants was determined during unilateral and bilateral tourniquet cuff inflation in supine, seated, and standing position. All measurements were completed in one experimental session with a rest period of 5 min in between. At the beginning and end of each condition, heart rate and blood pressure were recorded.ResultsRegardless of body position, AOP was higher during bilateral compared to unilateral tourniquet cuff inflation (mean difference = 3.2 mmHg [95% confidence interval: 1.0, 5.4], p = 0.006, d = 0.12). Furthermore, AOP and heart rate increased with change in body position from supine to seated to standing position (p < 0.001, d ≥ 0.76).DiscussionEven though there was a statistically significant difference in AOP between unilateral and bilateral tourniquet cuff inflation irrespective of body position, bilateral cuff inflation during AOP determination appears to have only minor impact on AOP in the lower extremities given the small mean difference and trivial effect size. However, since differences in AOP between unilateral and bilateral tourniquet cuff inflation of ≥ 30 mmHg have been recorded, practitioners must be aware of potentially pronounced differences between unilateral and bilateral cuff inflation during AOP determination in some individuals using the specific BFR device and AOP measurement protocol employed in this study. These results need to be verified for different inflation protocols, devices (i.e., manual versus automatic AOP determination), and populations (e.g., older adults, patients).

Background: Periprosthetic joint infections (PJI) represent a serious complication following joint arthroplasty and require, in addition to surgical intervention, a targeted antibiotic therapy. The aim of this study was to compare microbiological recommendations for the antibiotic treatment of fictitious PJI patients generated by an artificial intelligence (AI) system with those of an interdisciplinary team (IT) consisting of microbiologists and orthopedic surgeons. The differences between the recommendations suggested by AI and the IT were analyzed with regard to the suggested agents and duration of antibiotic therapy. Methods: Based on meta-analyses, a cohort of 100 fictitious patients with acute early- and acute late-onset PJI was created, reflecting the typical demographic data, comorbidities and pathogen profiles of such a population. This information was input into the AI system ChatGPT (OpenAI, GPT-5 "Thinking mode" accessed via ChatGPT Plus, San Francisco, CA, USA) to generate corresponding recommendations. The objective was to use these profiles to obtain recommendations for definitive antibiotic therapy, including daily dosage, intravenous and oral treatment durations. Simultaneously, the same fictitious patient data were reviewed by the IT to produce their own recommendations. Results: The results revealed both concordances and discrepancies in the selection of antibiotics. Notably, in cases involving multidrug-resistant organisms and more complex clinical scenarios, the AI-generated recommendations were incongruent with those of the IT, with estimated percentage agreement ranging from 0-33%. In straightforward clinical scenarios with monomicrobial infections, AI reached an estimated percentage agreement of up to 57% (95%-CI [0.47-0.67]). Furthermore, AI consistently recommended 12 weeks of therapy duration vs. six weeks usually recommended by the IT. Conclusions: The study provides important insights into the potential and limitations of AI-assisted decision-making models in orthopedic infection treatments. Consultation of AI is universally accessible at all times of day, which may offer a significant advantage in the future for the treatment of PJI. This kind of application will be of particular interest for institutions without in-house microbiology services. However, from our perspective, the current level of incongruence between the AI-generated recommendations and those of an experienced interdisciplinary team remains too high for this approach to be clinically implemented at this time. Furthermore, AI lacks transparency regarding the sources it uses to inform about its decision-making and therapeutic recommendations, currently carries no legal weight and clinical implementation is severely hindered by restrictive privacy laws regarding health care data.

Intensive care unit-acquired weakness (ICUAW) is a prevalent secondary disorder in critically ill patients, characterized by significant loss of muscle mass and strength, often leading to prolonged ICU stays, increased mortality, and reduced post-discharge quality of life. Despite guidelines recommending early mobilization, logistical challenges and inconclusive efficacy have limited its impact on ICUAW prevalence. This study aims to assess the feasibility, safety, and clinical efficacy of exclusively passive physiotherapeutic interventions, including blood flow restriction/ischemic preconditioning (BFR/IPC) and electromyostimulation (EStim), as potential alternatives for muscle preservation in ICU patients who are often sedated or unable to participate in active rehabilitation. This prospective, randomized controlled trial will recruit 120 patients from the surgical ICU at the University Hospital Bonn, who meet the inclusion criteria of a > 48-h ICU stay. Patients will be randomized into four groups: Sham-Control, BFR/IPC, EStim, and combined BFR/IPC + EStim. The study’s primary endpoints include feasibility and safety metrics, such as patient compliance and stress response, alongside secondary endpoints related to clinical outcomes like ICU length of stay, ICUAW prevalence, muscle mass preservation, and rehabilitation efficacy. Measurements include non-invasive assessments of muscle mass, intramuscular microdialysis to monitor metabolic and inflammatory markers, and health-related quality of life evaluations post-discharge. Preliminary literature and a systematic review underscore the need for resource-efficient, non-invasive interventions in ICU settings. BFR/IPC and EStim present promising results, but existing data on their efficacy in ICU populations are limited. This study’s findings will provide foundational data on the viability of passive physiotherapy techniques in ICU settings, potentially improving patient outcomes and reducing healthcare costs associated with prolonged ICU stays. If successful, these results will inform a multicenter randomized trial to further evaluate these interventions. This research represents a crucial step in developing feasible rehabilitation protocols to mitigate ICUAW, addressing a critical gap in critical care management and rehabilitation. ClinicalTrials.gov DRKS00033592. Registered on March 05, 2024.

Background: Periprosthetic joint infections (PJIs) remain a major challenge in arthroplasty. This study tries to evaluate the PJI-TNM classification as predictor for the revision-free implant survival in patients with PJI of the hip or knee joint. Methods: To this end, we perform a retrospective study of all consecutive patients with PJI of an inlying hip or knee arthroplasty between January 2015 and December 2019. Results: A total of 443 cases (hip: n = 247; knee n = 196) were identified. In total, 439 patients underwent surgery (DAIR: n = 138 cases (31%), explantation: n = 272 (61%), irrigation with debridement without exchange of implant components: n = 29 (6.5%)). Four patients refused surgical treatment and 39.5% were lost to follow-up. In total, 78 patients died during follow-up and 27 deaths were directly related to PJI/complications during treatment. Patients with inlying “standard”-implants (p < 0.001) and without previous history of PJI (p = 0.002) displayed a significantly higher postoperative revision-free implant survival. In terms of the PJI-TNM subclassification, patients with loosened implants but without soft-tissue defects (T1) displayed the highest revision-free implant survival. In contrast, patients classified as M3 (no surgical treatment possible) displayed an inferior outcome compared to M0, M1, or M2. Patients with different N-subclassifications (“non-human cells”/causative pathogen) did not display differences in revision-free implant survival. Conclusions: The PJI-TNM classification is well suited to classify PJIs. Its complexity allows for more than 500 different combinations of classifications. Further validation data are needed, but to us, the PJI-TNM classification seems to offer the possibility of comparing patients with PJIs. It may, therefore, be a very valuable tool in order to compare cohorts with PJIs and provide individual data for patient specific outcomes.

Despite growing interest in blood flow restriction (BFR) for enhancing training adaptations, its acute impacts on local and systemic physiological stress remain incompletely understood. This study compared the metabolic and perceptual responses of low-intensity cycling (LI) with BFR (LI + BFR) to both LI and high-intensity (HI) cycling without BFR, matched for time and external work. Ten males (26.9 ± 4.6 years) completed LI (20 min at 55% peak aerobic power output, PPO), LI + BFR (with 50% limb occlusion pressure), and HI (10 × 1 min at 90% PPO interspersed with 1-min recovery at 20% PPO) protocols in a randomized cross-over design. Interstitial metabolic responses were assessed via microdialysis in the vastus lateralis; systemic blood responses were evaluated via venous blood gas analysis. Cardiorespiratory responses, including heart rate, oxygen uptake, and ventilation, were continuously monitored during exercise. Serum creatine kinase (CK) and lactate dehydrogenase (LDH) were measured as indirect markers of muscle damage, and perceptual responses were documented. Muscle interstitial lactate and pyruvate were highest in HI, followed by LI + BFR, and lowest in LI (p < 0.05). Systemic blood and cardiorespiratory responses were comparable between LI + BFR and HI and exceeded LI (p < 0.05), while electrolyte shifts occurred across all conditions (p < 0.001) without between-condition differences. All protocols increased CK and LDH 24-48 h post-exercise, with the greatest increases in HI (p < 0.05). Perceived exertion and pain were higher in LI + BFR than in other conditions (p < 0.05). In conclusion, BFR intensifies local and systemic stress during LI and may be a potent strategy to promote muscle adaptive stimulus. However, when time and total external work are matched, high mechanical loading appears more effective in inducing local stress, which may be essential for further muscular adaptation processes.

Background: Periprosthetic joint infection (PJI) is one of the most serious complications following total joint arthroplasty. The debridement, antibiotics, irrigation, and implant retention (DAIR) procedure is commonly employed to treat acute, early-stage infections, but its success is highly variable, influenced by factors such as pathogen virulence and antibiotic susceptibility profiles. This study aimed to evaluate the impact of pathogens responsible for these infections on the outcome of DAIR. Methods: This retrospective, single-center study analyzed the microbiological profiles of 116 patients (66 hips and 50 knees) treated for acute periprosthetic joint infections (PJIs) with DAIR between 2018 and 2022. Acute PJI was defined as a duration of symptom less than three weeks, according to the criteria established by the Tsukayama and Izakovicova classification. Preoperative joint aspirations, intraoperatively collected tissue samples, and sonication of the exchanged mobile parts were analyzed for each case. We differentiated between monomicrobial PJI, polymicrobial PJI (defined as the identification of more than one microorganism from preoperative joint fluid aspiration or intraoperative samples), and difficult-to-treat (DTT) pathogens. Results: In this cohort, the following pathogen profiles were identified: culture-negative cases accounted for 11.1% of infections, while 64.2% were attributed to Gram-positive bacteria, 19.8% to Gram-negative bacteria, and 4.9% to fungal pathogens. Among the identified microorganisms, coagulase-negative staphylococci (CNS) were the most frequently detected, exhibiting a notable oxacillin resistance rate of 52.9% and rifampicin resistance rate of 28.7%. Additionally, no significant difference in revision-free implant survival was found between patients with DTT pathogens and/or polymicrobial PJI and those without such infections. Conclusions: This study highlights that pathogens in prosthetic joint infections (PJIs) do not solely determine outcomes, as patient-specific factors (comorbidities, implant type) may also play a key role. Regional variations in pathogens and antibiotic resistance patterns should guide empirical therapy. For instance, this study found a high reliance on vancomycin due to high oxacillin resistance in CNS, the most frequent causative pathogen.

Low-load resistance training with blood flow restriction (BFR) has gained popularity for eliciting muscular adaptations comparable to high-load resistance training. However, its acute metabolic and electrolyte responses within the exercising limb, particularly under exhaustive conditions, remain insufficiently characterized. This study aimed to assess these responses using simultaneous arterial and venous blood sampling during unilateral elbow flexion to volitional failure under three conditions: low-load (LL-RT, 30

The full spectrum of diseases caused by S. infantarius remains poorly understood, particularly its role in musculoskeletal infections. A retrospective study was conducted from January 2008 to May 2024. Patients with bacterial infections and detection of S. infantarius in at least one tissue sample, fluid sample, or blood cultures were included. Follow-up controls in patients with musculoskeletal infection were performed. S. infantarius could be identified in at least one sample (blood cultures, wound fluid, wound swab, bile, tissue or urine sample) of 72 patients. 33 were considered clinically relevant with symptomatic infections (63.4 ± 21.1 years; positive samples: 1.39 ± 0.86; total number of samples: 2.7 ± 1.76). Non-muskuloskeletal infections (n = 29; 61.1 ± 21.5 years; positive samples: 1.28 ± 0.59) included a variety of different infections (sepsis (n = 11), abdominal/gastrointestinal/urogenital infections (n = 16), soft tissue infections (n = 2)). Four patients with musculoskeletal S. infantarius infection (positive samples: 2.25 ± 1.89; diagnosis: acute PJI, spondylodiscitis, chronic PJI and postoperative spinal wound infection) required surgical and/or antimicrobial treatment. Follow-up after musculoskeletal infection varied between 10 and 60 months. Antibiotic susceptibility testing displayed a sensitivity to Penicillin in all isolates. No patient had a recurrent positive sample/infection with S. infantarius. This study describes musculoskeletal infections caused by S. infantarius, highlighting its possible relevance as pathogen in orthopedic infections. The findings underscore the importance of recognizing and appropriately treating S. infantarius. In case of penicillin allergy, clindamycin shows to be an effective alternative treatment.

Strength training responses are influenced by sets, repetitions, and mechanical load, whereas Blood Flow Restriction (BFR) training adds the variable of temporarily restricting blood flow via a tourniquet. This has intensified scientific discussions regarding the vascular responses and thereby safety of the BFR method. To address these concerns, we investigated intravascular pressure changes during low-load (LL-RT), low-load with BFR (LL-BFR-RT), and high-load (HL-RT) exercise. Ten healthy men (26.8 ± 4.59 years) performed unilateral biceps curls to failure in a randomized cross-over design: (1) LL-RT (30% 1RM), (2) LL-BFR-RT (30% 1RM, 50% LOP), and (3) HL-RT (75% 1RM). Total workload was significantly higher in LL-RT (692 ± 251 kg) compared to LL-BFR-RT (378 ± 58.7 kg) and HL-RT (327 ± 65.1 kg, p < 0.001). In terms of mean values, LL-BFR-RT resulted in higher diastolic and mean arterial pressures during rest periods between sets compared to other conditions (p ≤ 0.02). Both LL-RT and LL-BFR-RT led to longer durations spent at increased diastolic (above 90 mmHg, LL-RT: ~419 s vs. LL-BFR-RT: ~356 s vs. Hl-RT: ~122 s), systolic (above 140 mmHg, LL-RT: ~437 s vs. LL-BFR-RT: ~336 s vs. HL-RT: ~199 s), and mean arterial pressures (above 107 mmHg, LL-RT: ~451 s vs. LL-BFR-RT: ~384 s vs. HL-RT: ~168 s) compared to HL-RT (p ≤ 0.028). Relative to total exercise time, LL-BFR-RT resulted in higher proportion of time spent at elevated diastolic (above 90 mmHg, LL-RT: ~56.5% vs. LL-BFR-RT: ~68.7% vs. Hl-RT: ~33.5%) and mean arterial pressures (above 107 mmHg, LL-RT: ~60.8% vs. LL-BFR-RT: ~74.0% vs. HL-RT: ~45.7%) compared to HL-RT (p ≤ 0.034). Peripheral venous pressure was significantly higher in LL-BFR-RT compared to other conditions (p < 0.001), with both absolute and relative time spent at higher pressures (above 75 mmHg, LL-RT: ~57.0 s and ~ 9.12% vs. LL-BFR-RT: ~424 s and ~ 81.7% vs. HL-RT: ~36.0 s and ~ 8.99%, p ≤ 0.002). Our results suggest that BFR training performed to failure imposes greater arterial and venous stress in the exercising limb compared to high-load training without BFR, particularly due to prolonged exposure to elevated pressures. Further research is needed to assess the potential risks of elevated local arterial and venous pressure responses by frequent BFR use, particularly in populations with pre-existing medical conditions.

Periprosthetic joint infections (PJIs) are severe complications following total joint arthroplasty, with significant implications for implant longevity and patient quality of life. The debridement, antibiotics, irrigation, and implant retention (DAIR) procedure is a key strategy for managing acute PJIs while preserving the prosthesis. However, its success is highly variable, influenced by factors such as pathogen virulence and patient-specific risks. We set out to evaluate revision-free implant survival and potential risk factors influencing outcome at our institution. This retrospective, single-center study analyzed a total of 110 patients (60 hip and 50 knee) treated for acute periprosthetic joint infections (PJI) with DAIR between 2017 and 2022. Exchange of mobile parts was undertaken in all cases. Postoperative management followed a standardized protocol, consisting of two weeks of intravenous antibiotics followed by four weeks of oral antibiotics. Clinical and radiological follow-ups were conducted at predefined intervals, assessing implant stability and signs of reinfection. Comprehensive patient data, including demographics, infection markers, microbiology, implant type, and prior surgical history, were collected and analyzed statistically. Overall, 23.6% (n = 26) of patients were lost to follow-up. Of the remaining 84 patients, we were able to detect 31 cases of tier 1 success according to Fillingham outcome criteria, which represents 36.9%. The patients in whom DAIR failed, tended to be older, have more comorbidities and showed a higher total cell count in preoperative joint aspiration. Furthermore, prior revision arthroplasty was associated with a significantly higher failure rate in the knee group. A preoperative assessment of the likelihood of DAIR success should be undertaken for each patient. For this assessment, our data indicates to look at patient specific factors such as age, ASA score, revision implant, and preoperative cell count. These aspects may enhance risk evaluation and support the selection of an alternative treatment strategy when appropriate.

Background Muscle hypertrophy, the increase in skeletal muscle mass, is a critical adaptive response to resistance training and a key factor not only in athletic performance but also in the clinical setting, such as pre- and rehabilitation. This paper aims to provide a comprehensive overview of the anabolic signals that contribute to muscle hypertrophy and discuss their strategic application in prehabilitation and rehabilitation contexts. Materials and Methods In this narrative review, we examine the primary mechanisms driving muscle growth, including mechanical tension, metabolic stress, and muscle damage, and their molecular mediators such as mTOR signaling, satellite cell activation, and hormonal responses. The review explains how these signals can be manipulated through various training variables, including contraction type, exercise selection, volume, intensity, and frequency. We also discuss the role of nutrition, particularly protein intake and timing, in optimizing the hypertrophic response. Results The current data shows that, contrary to previous assumptions, high mechanical tension is not mandatory to stimulate muscle growth. Metabolic stress is another effective anabolic signal, which expands the range of training stimuli for pre- and rehabilitation training into an important area. Conclusion By integrating current scientific understanding of muscle hypertrophy mechanisms with practical clinical considerations, the results equip sports orthopedists and rehabilitation professionals with evidence-based strategies to enhance the effectiveness of their interventions and improve outcomes for athletes and non-athletes across various stages of their careers and recovery processes.

Blood flow restriction (BFR) training has been shown to induce exercise-induced muscle damage (EIMD) in some cases, although findings are inconsistent and the influence of the applied arterial occlusion pressure (AOP) remains unclear. This single-blind, randomized controlled trial investigated the effects of different percentages of AOP on EIMD and acute physiological responses in 40 participants allocated to four groups: no pressure (NP), low pressure (LP; 50% AOP), medium pressure (MP; 75% AOP), and high pressure (HP; 100% AOP). Participants performed unilateral knee extensions at 30% of their one-repetition maximum up to four sets of 20 repetitions or until failure. EIMD was primarily assessed by the changes in isokinetic peak torque 24 h, 48 h and 72 h post-exercise (Δ to baseline). Secondary markers included perceived pain, blood biomarkers (creatine kinase, myoglobin) and muscle swelling. Additionally, acute physiological responses were assessed, including continuous measurement of muscle oxygen saturation (SmO2) during exercise, perceived exertion (RPE) immediately after the exercise bout, and blood lactate concentration measured at 1, 3, 7, and 10 min post-exercise. NP showed greater strength loss at 24 h post-exercise compared to MP (MD = − 9.95, p = .042, 95% CI [− 19.7, − 0.19]) and HP (MD = − 10.51, p = .034, 95% CI [− 20.52, − 0.49]). Pain ratings were higher in NP compared to MP (p = .001) and HP (p = .003) at 24 h post, and remained elevated at 48 h compared to MP (p = .003) and HP (p = .047). NP and LP completed more repetitions than MP and HP. HP exhibited a greater reduction in SmO2compared to NP. Perceived exertion was higher in MP and HP. LP showed higher average lactate concentrations than NP (p = .020). CK and MB responses showed no time-specific group differences. These findings suggest that BFR training, even at higher pressures, does not increase EIMD compared to free-flow exercise, and that MP and HP may even attenuate strength loss and pain following exercise.

Introduction: Two-stage revision with an antibiotic-loaded, temporary static cement spacer is a common treatment for periprosthetic joint infection (PJI) of the knee. However, limited data exists on in vivo antibiotic elution kinetics after spacer implantation. This pilot study uses the technique of microdialysis (MD) to collect intra-articular knee samples. The aim was to evaluate MD as an intra-articular sampling method to detect spacer-eluted antibiotics within 72 h after surgery and to determine whether they show specific elution kinetics. Methods: Ten patients (six male, four female; age median 71.5 years) undergoing two-stage revision for knee PJI were included. A MD catheter was inserted into the joint during explantation of the infected inlying implant and implantation of a custom-made static spacer coated with COPAL cement (0.5 g gentamicin (G) and 2 g vancomycin (V)). Over 72 h postoperatively, samples were collected and analyzed for spacer-eluted antibiotics, intravenously administered antibiotics (e.g., cefazolin and cefuroxime), metabolic markers (glucose and lactate), and Interleukin-6 (IL-6). Local and systemic levels were compared. Results: All catheters were positioned successfully and well tolerated for 72 h. Antibiotic concentrations in MD samples peaked within the first 24 h (G: median 9.55 µg/mL [95% CI: 0.4–17.36]; V: 37.57 µg/mL [95% CI: 3.26–81.6]) and decreased significantly over 72 h (for both p < 0.05, G: 4.27 µg/mL [95% CI: 2.26–7.2]; V: 9.69 µg/mL [95% CI: 3.86–24]). MD concentrations consistently exceeded blood levels (p < 0.05), while intravenously administered antibiotics showed higher blood concentrations. Glucose in MD samples decreased from 17.71 mg/dL to 0.89 mg/dL (p < 0.05). IL-6 and lactate concentrations showed no difference between MD and blood samples. Conclusions: Monitoring antibiotics eluted by a static spacer with intra-articular MD for 72 h is feasible. Gentamicin and vancomycin levels remained above the minimal inhibitory concentration. Differentiating infection from surgical response using metabolic and immunological markers remains challenging. Prolonged in vivo studies with MD are required to evaluate extended antibiotic release in two-stage exchanges.

Background There is no consensus concerning the rehabilitation protocol following reverse shoulder arthroplasty. Several patients are expecting to be able to use their arms for sports or recreation shortly after their operation. Methods This review was designed as an intervention systematic review with narrative analysis. Authors searched English literature in PubMed and Embase databases from 1/1/1989 until July 2022. Controlled studies comparing rehabilitation protocols for patients undergoing reverse shoulder arthroplasty were included. Data quality was examined with the Cochrane risk of a bias assessment tool for randomized trials, the Methodological Index for Non-Randomized studies (MINORS) tool, as well as the Grading of Recommendations Assessment Development and Evaluation (GRADE) approach. Results Three studies were finally analyzed. At 3 months post-op, forward flexion was found to be significantly higher in the early rehabilitation group (140.5, 95% confidence intervals (CIs): 135.10–145.89; the delayed rehabilitation group mean was 131.24, 95% CI: 125.73–136.74; p = 0.019). Twelve months post-op, no significant difference in any clinical or patient-reported outcome was shown. More complications were reported in the 6 weeks-delayed rehabilitation group. Discussion Newer regimes permit immediate shoulder mobilization but may not be applied to every patient. The lack of strong evidence warrants the need for future controlled studies; subsequently, postoperative rehabilitation should be individualized.

ABSTRACTLow‐load blood‐flow‐restriction resistance training (LL‐BFR‐RT) is gaining popularity, but its physiological effects remain unclear. This study aimed to compare LL‐BFR‐RT with low‐load resistance exercise (LL‐RT) and high‐load resistance exercise (HL‐RT) on metabolism, electrolytes, and ions in the lower extremities by invasive catheter measurements, which are crucial for risk assessment. Ten healthy men (27.6 ± 6.4 years) completed three trials of knee‐extensor exercises with LL‐RT (30% 1RM), LL‐BFR‐RT (30% 1RM, 50% limb occlusion pressure), and HL‐RT (75% 1RM). The exercise protocol consisted of four sets to voluntary muscle failure with 1 min of rest between sets. Blood gas analysis was collected before, during, and after each trial through intravenous catheters at the exercising leg. LL‐BFR‐RT had lower total workload (1274 ± 237 kg, mean ± SD) compared to LL‐RT (1745 ± 604 kg), and HL‐RT (1847 ± 367 kg, p < 0.01), with no difference between LL‐RT and HL‐RT. Pain perception did not differ significantly. Exercise‐induced drop in oxygen partial pressure, lactate accumulation and electrolyte shifts (with increased [K+]) occurred during under all conditions (p < 0.001). Creatine kinase and lactate dehydrogenase increased significantly 24‐ and 48‐h postexercise under all three conditions (p < 0.001). This study, using invasive catheter measurements, found no significant differences in metabolic, ionic, and electrolyte responses among LL‐BFR‐RT, LL‐RT, and HL‐RT when exercised to voluntary muscular failure. LL‐BFR‐RT reduced time to failure without specific physiological responses.

Der Ersatz des Kniegelenks mittels einer Totalendoprothese (TKA) gilt als eine der häufigsten und erfolgreichsten Operationen des orthopädischen Fachgebietes mit stetig wachsenden Patientenzahlen. Einhergehend mit der zum Teil immer jünger werdenden Patientenklientel verändern sich jedoch auch die Erwartungshaltungen an das operative Outcome. Neben der Schmerzreduktion und der Verbesserung der Beweglichkeit sind auch die Langlebigkeit der Prothese und die Wiedererlangung von (Alltags‑)Aktivität im Allgemeinen („return-to-activity“ [RtA]) sowie von sportlicher Aktivität im Speziellen („return-to-sports“ [RtS]) von zunehmender Bedeutung. RtS mit Tendenz zu „Low-impact“-Sportarten scheint generell möglich, ist jedoch stark abhängig von den individuellen Eigenschaften des Patienten. Trotz umfangreicher Studienlage zur Versorgung mittels TKA, gibt es bisher keine systematischen Untersuchungen und aussagekräftigen Ergebnisse zu den entscheidenden Faktoren, die einen Wiedereintritt in eine sportliche Belastung nach TKA ermöglichen. Eine entsprechende Empfehlung seitens der behandelnden Chirurgen bleibt mangels standardisierter Implementierung eines RtA/RtS-Assessment sowie einer notwendigen Verlaufsbeobachtung im Langzeit-Follow-up unter Kontrolle der patientenbezogenen Störfaktoren, abhängig von deren subjektiven Erfahrungen.

Spondylodiscitis is a severe spinal infection that requires an effective antibiotic treatment. Therefore, we sought to analyse the causative pathogens from intraoperative specimen in patients with spondylodiscitis and a need for surgery. To this end, we performed a retrospective study of all patients with spondylodiscitis and a need for operative treatment admitted to our hospital between January 2020 and December 2022. A total of 114 cases with spondylodiscitis were identified. A total of 120 different pathogens were detected. Overall, 76.7% of those microorganisms were Gram-positive bacteria. The most common causative pathogen was Staphylococcus aureus (n = 32; 26.6%), followed by coagulase-negative staphylococci (n = 28; 23.4%), of which Staphylococcus epidermidis (n = 18; 15%) was the most frequently detected, as well as enterococci (n = 10; 8.4%) and Streptococcus spp. (n = 11; 9.2%). Moreover, 19.1% (n = 22) and 3.4% (n = 4) of all detected isolates were Gram-negative pathogens or fungi, respectively. Overall, 42.8% of all coagulase-negative staphylococci were oxacillin-resistant, while none of them were vancomycin-resistant. In summary, 50% of the pathogens could be identified as staphylococci. The results of our study highlight the important burden of oxacillin-resistant Gram-positive bacteria as an aetiological cause of spondylodiscitis, providing a relevant finding for antimicrobial stewardship programmes.

AbstractPhysical exercise induces acute psychophysiological responses leading to chronic adaptations when the exercise stimulus is applied repeatedly, at sufficient time periods, and with appropriate magnitude. To maximize long-term training adaptations, it is crucial to control and manipulate the external load and the resulting psychophysiological strain. Therefore, scientists have developed a theoretical framework that distinguishes between the physical work performed during exercise (i.e., external load/intensity) and indicators of the body's psychophysiological response (i.e., internal load/intensity). However, the application of blood flow restriction (BFR) during exercise with low external loads/intensities (e.g., ≤ 30% of the one-repetition-maximum, ≤ 50% of maximum oxygen uptake) can induce physiological and perceptual responses, which are commonly associated with high external loads/intensities. This current opinion aimed to emphasize the mismatch between external and internal load/intensity when BFR is applied during exercise. In this regard, there is evidence that BFR can be used to manipulate both external load/intensity (by reducing total work when exercise is performed to exhaustion) and internal load/intensity (by leading to higher physiological and perceptual responses compared to exercise performed with the same external load/intensity without BFR). Furthermore, it is proposed to consider BFR as an additional exercise determinant, given that the amount of BFR pressure can determine not only the internal but also external load/intensity. Finally, terminological recommendations for the use of the proposed terms in the scientific context and for practitioners are given, which should be considered when designing, reporting, discussing, and presenting BFR studies, exercise, and/or training programs.

Acute and overuse injuries and chronic disabilities of the musculoskeletal system often led to reduced mobility, resulting in muscle weakness and atrophy. Traditional rehabilitation techniques are frequently unsuitable to induce muscle hypertrophy in the early stages of recovery due to physical restrictions for the patient or exercise-induced pain caused by necessary high mechanical loads. Blood Flow Restriction (BFR) training has emerged as a promising alternative, allowing for significant muscular adaptations with low mechanical loads. This technique uses specialized cuffs to modify blood flow during active and passive interventions, stimulating muscle growth and strength comparable to high-load resistance training. While BFR training shows potential for rehabilitation and elite sports, it presents specific risks, particularly in clinical settings. Therefore, this narrative review aims to describe the mechanisms, benefits, and potential risks of BFR training. Additionally, its application in both rehabilitation settings and elite sports will be highlighted by providing recommendations for its safe and effective use.