Shoulder dislocations in professional male football (soccer): A retrospective epidemiological analysis of the German Bundesliga from season 2012/2013 until 2022/2023.

PURPOSE: Injuries exert a detrimental impact on the team performance in professional football. Shoulder dislocations are known for their severity and often cause substantial lay-off times. However, there is a notable gap in the general understanding regarding the frequency and convalescence of these events in professional football. Thus, the aims of this study were (1) to determine the incidence, (2) to evaluate return to competition (RTC) and redislocation events (RDEs) and (3) to identify relevant player-, match- and injury-related parameters. METHODS: All shoulder dislocations within the highest three German football leagues (1.-3. Bundesliga) during the seasons 2012/2013 until 2022/2023 were identified. Player-, injury- and match-related data were obtained by performing a media analysis. Data were analysed using descriptive statistics. p Value was set at 0.05. RESULTS: A total of 90 first-time shoulder dislocations in 89 players with a median age of 25 years (interquartile range [IQR]: 23-28) were available for analysis. The incidence was 9.1 per 1000 Bundesliga matches played and increased over time. Forty-four (49%) shoulder dislocations were treated conservatively and 46 (51%) operatively. Median RTC was 24 days (IQR: 12-43) following conservative and 103 days (IQR: 85-135) following surgical treatment (p < 0.001). Twenty-two (24%) players suffered a redislocation, of whom 13 (59%) underwent initial conservative and nine (41%) initial surgical treatment (not significant [n.s.]). RDE following conservative treatment was after a median of 4 months (IQR: 2-22) and 7 months (IQR: 3-23) following surgical treatment (n.s.). CONCLUSION: The incidence of shoulder dislocation within professional football is increasing and currently amounts to 9.1 per 1000 matches played. A conservative treatment leads to a quicker RTC, while frequency and time to RDE were similar regardless of treatment. The increasing incidence of shoulder dislocations in professional football necessitates an analysis of relevant injury mechanisms and the implementation of specific preventive measures. LEVEL OF EVIDENCE: Level III.

How shoulder immobilization after surgery influences daily activity - a prospective pedometer-based study.

PURPOSE: Immobilization, especially of the lower extremity, after orthopaedic surgery has been associated with reduced physical activity. Previous interventions from our study group showed even in young, healthy people reduced activity levels after immobilization of the shoulder. Therefore, this study investigates the change in physical activity due to shoulder immobilization after a reconstructive surgery. METHODS: This prospective study includes 40 patients undergoing surgery from May 2019 to December 2020. Daily activity was measured before surgery, after discharge and three weeks postoperatively each time for six days. Activity including step counts and active time were measured by Fitbit™ inspire. Range of motion before and after surgery as well as Pain (VAS) were documented. RESULTS: Steps became significantly less immediately postoperatively with an immobilized shoulder joint than before surgery (9728.8 vs. 6022.6, p < 0.05). At follow-up, the number of steps increased again, but still showed a significantly lower number of steps (mean 8833.2) compared to preoperative. Patients preoperatively showed mostly an "active" activity pattern, whereas postoperatively a "low active" behaviour predominated. The proportion of sedentary behaviour ("basal activity" and "limited activity") was almost three times higher postoperatively (12.5% vs. 30%). CONCLUSION: General physical activity is restricted during upper limb immobilization in adults. Therefore, activity-enhancing measures should be implemented in the early phase of rehabilitation after upper extremity surgery.

Surgeons' non-transparent facemasks challenge the physician-patient relationship in the orthopedic outpatient clinic of a tertiary university hospital during the COVID-19 pandemic: a prospective cohort study of 285 patients.

Background and purpose - Facemasks play a role in preventing the respiratory spread of SARS-CoV-2, but their impact on the physician-patient relationship in the orthopedic outpatient clinic is unclear. We investigated whether the type of surgeons' facemask impacts patients' perception of the physician-patient relationship, influences their understanding of what the surgeon said, or affects their perceived empathy. Patients and methods - All patients with an appointment in the orthopedic outpatient clinic of a tertiary university hospital during the 2-week study period were included. During consultations, all surgeons wore a non-transparent (first study week) or transparent facemask (second study week). Results of 285 of 407 eligible patients were available for analysis. The doctor-patient relationship was evaluated using the standardized Patient Reactions Assessment (PRA) and a 10-point Likert-scale questionnaire ranging from 0 (strongly disagree) to 10 (strongly agree). Results - A non-transparent facemask led to more restrictions in the physician-patient communication and a worse understanding of what the surgeon said. Patients' understanding improved with a transparent facemask with greatest improvements reported by patients aged 65 years and older (non-transparent: 6 [IQR 5-10] vs. transparent: 10 [IQR 9-10], p < 0.001) and by patients with a self-reported hearing impairment (non-transparent: 7 [IQR 3-7] vs. transparent: 9 [IQR 9-10], p < 0.001). The median PRA score was higher when surgeons wore a transparent facemask (p= 0.003). Interpretation - Surgeons' non-transparent facemasks pose a new communication barrier that can negatively affect the physician-patient relationship. While emotional factors like affectivity and empathy seem to be less affected overall, the physician-patient communication and patients' understanding of what the surgeon said seem to be negatively affected.

Function and return to sports after proximal humeral replacement in patients with primary bone sarcoma.

BACKGROUND: Improved patient and limb survival rates have led to an increased interest in the functional outcome and return to sports of patients undergoing megaprosthetic reconstruction in musculoskeletal oncology. This study evaluates the functional outcome and postoperatively performed level of sports in patients undergoing proximal humeral replacement (PHR) following resection of a primary bone sarcoma and identifies potential beneficial and limiting factors. PATIENTS AND METHODS: Between 2007 and 2020, a total of 606 patients underwent resection of a primary bone sarcoma and reconstruction with a single-design modular implant. For 112 (18%) patients, the location of the tumour was the proximal humerus. Exclusion criteria were death (n = 65), patients living overseas (n = 8), and subsequent amputation (n = 1), leaving 38 patients for evaluation, of whom 32 were available for the study (13 women, median age 42 years). Clinical data regarding oncological and surgical treatment as well as subsequent complications were obtained from the patients' electronic medical records. Functional outcome was determined using the Musculoskeletal Tumor Society Score (MSTS) and Toronto Extremity Salvage Score (TESS) as well as the Subjective Shoulder Value (SSV). Return to sports was assessed using the Tegner Activity Score (TS) and the modified Weighted Activity Score (WAS). RESULTS: At the last follow-up after a median of 30 months (IQR 22-58), median MSTS was 18 (IQR 12-24), median TESS was 80% (IQR 69-87), median SSV was 35% (IQR 10-58), median TS was 5 (IQR 4-6) and median WAS was 5 (IQR 0-10). Preservation of the axillary nerve, a reverse shoulder reconstruction and a WAS of > 10 prior to surgery were associated with better functional outcome and return to sports activity scores. CONCLUSION: Following PHR, good to excellent functional outcomes are possible, and patients regularly return to participate in sports activities-most commonly in low-impact types of sports, but some individuals are even able to participate in high-impact sports activities. LEVEL OF EVIDENCE: IV.

Single-row vs. double-row refixation of the subscapularis tendon after primary anatomic shoulder arthroplasty.

BACKGROUND: The postoperative integrity of the subscapularis tendon after primary anatomical shoulder arthroplasty has a significant effect on postoperative results. A transosseus Single Row Refixation technique (SRR) has shown up to 30% of partial tears in literature, a modified Double Row Refixation technique (DRR) has biomechanically shown a significantly reduced tear rate, but is yet to be proven in a clinical setting. Thus, we compared the SRR to the DRR technique using clinical outcome parameters and ultrasound examination. MATERIALS AND METHODS: 36 patients (40 shoulders; 20f, 16 m; øage: 66 years) were included in our retrospective cohort study. 20 shoulders were treated with the SRR technique (12f, 8 m; FU ø40.9 months) and 20 with the DRR technique (11f, 9 m; FU ø31.6 months). The SRR was performed with three to five transosseus mattress sutures. DRR consisted of two medial placed transosseus sutures and four laterally placed single tendon-to-tendon sutures. The postoperative subscapularis integrity was evaluated by ultrasound examination, the clinical outcome was assessed with the Constant-Murley Score (CS) and the American Shoulder and Elbow Surgeons Score (ASES). RESULTS: The subscapularis tendon was intact in 14 patients (70%) after SRR, whereas 18 patients (90%) treated with the DRR demonstrated a sonographically intact postoperative subscapularis tendon. The CS was 61.4 points in the SRR cohort and 67.3 points in the DRR cohort (p = 0.314). No significant differences were found in both cohorts preoperative (øSRR: 21.3 points; øDRR: 16.2 points, p = 0.720) and postoperative absolute ASES Scores (øSRR: 70.2 points; øDRR: 73.0 points, p = 0.792). However, the DRR cohort showed a statistical tendency to a higher postoperative ASES increase than the SRR cohort (øSRR-ASES increase: 48.9 points; øDRR-ASES increase: 56.8 points, p = 0.067). CONCLUSION: The results of this study show that application of the DRR technique can significantly reduce the total rate of postoperative subscapularis tears what effects a clinical tendency towards higher ASES improvements and a better range of motion compared to the SRR technique.

[Postinfectious reactive arthritis after chlamydia infection in competitive sports : Clinical management and current literature review]. / Postinfektiöse reaktive Arthritis nach Chlamydieninfektion im Leistungssport : Klinisches Management und aktuelle Literaturübersicht.

BACKGROUND: Reactive arthritis following infection with chlamydia is a rare but important differential diagnosis in atraumatic joint swelling. A delayed diagnosis often leads to prolonged periods of absence from physical activity. This can have serious consequences, especially for the career of competitive athletes. OBJECTIVES: Recommendation for the clinical management of postinfectious reactive arthritis for rapid diagnosis and targeted treatment in the symptomatic clinical course. MATERIALS AND METHODS: Review of the literature on the topics "chlamydia", "reactive arthritis", "postinfectious arthritis" and "sexually acquired reactive arthritis", including presentation of two clinical cases of postinfectious reactive arthritis after chlamydia infection from competitive sports. RESULTS AND CONCLUSION: Reactive arthritis following chlamydia infection in competitive athletes is a rare entity. However, it can be accompanied by far-reaching individual consequences, especially with regard to possible downtime in sports. Long-term consequences such as chronic joint damage in maintained synovitis must also be considered. In order to make a diagnosis, a specific anamnesis and the direct detection of the pathogen in the specimen of synovial fluid by polymerase chain reaction is essential. This allows a reliable diagnosis to be made with immediate initiation of therapy. However, a prolonged course of the disease cannot be excluded even if therapy is started in due time.

[Imminent fracture of the tibia due to an osteolytic lesion caused by an intraosseous tenosynovial giant cell tumor : An unusual clinico-histopathological constellation]. / Stabilitätsgefährdende Osteolyse der Tibia durch einen intraossären tenosynovialen Riesenzelltumor : Eine außergewöhnliche klinisch-histopathologische Konstellation.

The tenosynovial giant cell tumor is a rare disease of the joint mucosa, tendon sheaths and bursa. We report on the rare constellation of an intraosseous manifestation of the proximal tibia of a lower leg stump after Burgess amputation as a result of a locally uncontrollable tenosynovial giant cell tumor of the upper ankle. The curettage of the local findings and operative stabilization through an intramedullary composite osteosynthesis led to an early rehabilitation of the exoprosthesis care with regaining patient autonomy.

How shoulder immobilization influences daily physical activity - an accelerometer based preliminary study.

BACKGROUND: To investigate the influence of shoulder immobilization on daily physical activity. INTRODUCTION: The harmful effect of sedentary behavior does not receive much attention in orthopedic surgery even though immobilization, especially of the lower extremity, has been associated with reduced physical activity. Immobilization of the shoulder is common after reconstructive shoulder surgery and could also potentially lead to reduced physical activity and have a negative effect on a patient's general health. METHOD: Twenty-one healthy volunteers were immobilized in an orthosis (DJO Ultrasling III) for 10 h on two consecutive days. In the following week, activity was measured on the same days without the orthosis. Activity including gait cycles per minute and total gait cycles per day was measured by accelerometer based step count StepWatchTMActivity Monitor. Average age was 26 +/- 3 years. A questionnaire was administered to evaluate subjective activity. RESULTS: Participants wearing the shoulder orthosis were significantly less active than without immobilization by 2227.5 gait cycles/day (5501.2 with SO, 7728.7 without SO). Also, significantly more time in sedentary behavior occurred (< 400 steps/h) when the shoulder was immobilized. Patients were significantly more active without shoulder orthosis in medium level activities (800-999 steps/h). Differences for low (400-799 steps/h) and high activity levels (> 1000 steps/h) were not statistically significant. Subjective limitations while wearing the orthosis were graded at 2.343 on a scale of 0-4. CONCLUSION: Results of this study show that even in young, healthy volunteers immobilization of the shoulder in an orthosis for 2 days leads to significantly reduced activity levels. A negative influence on general health, especially in older patients who are immobilized for up to 6 weeks, can potentially occur. Promoting physical activity during the immobilization period should be part of rehabilitation after injuries/surgery of the shoulder. TRIAL REGISTRATION: Retrospectively registered in DRKS (DRKS00017636).

α-Synuclein Penetrates Mucin Hydrogels Despite Its Mucoadhesive Properties.

Recent research indicates that the progression of Parkinson's disease can start from neurons of the enteric nervous system, which are in close contact with the gastrointestinal epithelium: α-synuclein molecules can be transferred from these epithelial cells in a prion-like fashion to enteric neurons. Thin mucus layers constitute a defense line against the exposure of noninfected cells to potentially harmful α-synuclein species. We show that-despite its mucoadhesive properties-α-synuclein can translocate across mucin hydrogels, and this process is accompanied by structural rearrangements of the mucin molecules within the gel. Penetration experiments with different α-synuclein variants and synthetic peptides suggest that two binding sites on α-synuclein are required to accomplish this rearrangement of the mucin matrix. Our results support the notion that the translocation of α-synuclein across mucus barriers observed here might be a critical step in the infection of the gastrointestinal epithelium and the development of Parkinson's disease.

Adaptive Changes on the Dominant Shoulder of Collegiate Handball Players-A Comparative Study.

Vogler, T, Schorn, D, Gosheger, G, Kurpiers, N, Schneider, K, Rickert, C, Andreou, D, and Liem, D. Adaptive changes on the dominant shoulder of collegiate handball players-A comparative study. J Strength Cond Res 33(3): 701-707, 2019-Handball players are susceptible to adaptive bony and soft-tissue changes of the dominant shoulder. Our goal was to compare the glenohumeral range of motion and posterior capsule thickness between the dominant and nondominant arm of throwing athletes and between the dominant arm of nonthrowers and throwing athletes. Twenty-three collegiate handball players and 23 nonthrowing athletes underwent an examination of the dominant and the nondominant shoulder. Humeral retroversion and posterior capsule thickness were assessed with an ultrasound examination, whereas external rotation and internal rotation were determined with a digital inclinometer. The dominant shoulder of handball players had a significantly higher external rotation compared with their nondominant shoulder and the dominant shoulder of nonthrowing athletes. Furthermore, the dominant shoulder of handball players had a significantly lower internal rotation compared with their nondominant shoulder, with no differences compared with the dominant shoulder of the nonthrowing athletes. There was a trend for an increased posterior capsule thickness and an increased humeral retroversion between the dominant and the contralateral shoulder of handball players. Moreover, we found a significant increase in the capsule thickness of the dominant shoulder of throwing athletes compared with the dominant shoulder of nonthrowers. However, there were no differences in humeral retroversion. Our analysis suggests that a comparison of the dominant shoulder of overhead throwing athletes with the dominant shoulder of nonthrowing athletes might be more appropriate than the comparison of the dominant and the nondominant shoulder to evaluate the adaptive changes on the dominant side.

Long-term outcomes after combined arthroscopic medial reefing and lateral release in patients with recurrent patellar instability - a retrospective analysis.

BACKGROUND: There is currently no consensus regarding the optimal surgical treatment method for patients with recurrent patella instability. Our goal was to evaluate the long-term results of combined arthroscopic medial reefing and lateral release, to identify possible risk factors for recurrent dislocations and residual complaints after surgical treatment and to assess functional outcome. METHODS: We performed a retrospective study of 38 patients (43 knees) treated with all-inside technique between 2001 and 2010. The functional outcome was evaluated with the Kujala score, while pain intensity was scored on a visual analogue scale (VAS). Contingency tables were analysed with Fisher's exact test. Non-parametric analyses were carried out with the Mann-Whitney U and the Wilcoxon signed-rank test. Survival curves were calculated with the Kaplan-Meier method and compared with the log-rank test. RESULTS: The median age at surgery was 16 years (range, 9-44 years) and the median follow-up amounted to 9.7 years (range, 4.7-14.7 years). Residual complaints were present in 34 cases (79%). Patients with residual complaints had a trend for a higher body mass index (BMI) at surgery (25.7 vs. 21.6, P = .086). Twenty-two cases had recurrent dislocation after a median interval of 30 months. The probability of recurrent dislocations amounted to 16% after 1 year and 52% after 10 years. There were no significant differences in the presence of residual complaints (P = .721) and median VAS score (P = .313) between patients with or without recurrent dislocation. Patients with recurrent dislocations had a trend towards younger age at surgery (15 vs. 18 years, P = .076). The median Kujala score of the affected knee was 81. Patients with recurrent dislocations had a significantly lower score compared to patients without recurrent dislocations (67 vs. 91, P < .001). CONCLUSIONS: The combined arthroscopic lateral release with medial reefing does not appear to be an adequate treatment for patients with chronic patellar instability in long-term follow-up. Younger patients might be at a higher risk for recurrent dislocations, while a higher BMI at surgery might be associated with residual complaints.

A Mucin-Based Bio-Ink for 3D Printing of Objects with Anti-Biofouling Properties.

With its potential to revolutionize the field of personalized medicine by producing customized medical devices and constructs for tissue engineering at low costs, 3D printing has emerged as a highly promising technology. Recent advancements have sparked increasing interest in the printing of biopolymeric hydrogels. However, owing to the limited printability of those soft materials, the lack of variability in available bio-inks remains a major challenge. In this study, a novel bio-ink is developed based on functionalized mucin-a glycoprotein that exhibits a multitude of biomedically interesting properties such as immunomodulating activity and strong anti-biofouling behavior. To achieve sufficient printability of the mucin-based ink, its rheological properties are tuned by incorporating Laponite XLG as a stabilizing agent. It is shown that cured objects generated from this novel bio-ink exhibit mechanical properties partially similar to that of soft tissue, show strong anti-biofouling properties, good biocompatibility, tunable cell adhesion, and immunomodulating behavior. The presented findings suggest that this 3D printable bio-ink has a great potential for a wide range of biomedical applications, including tissue engineering, wound healing, and soft robotics.

Multifunctional glycoprotein coatings improve the surface properties of highly oxygen permeable contact lenses.

To achieve and maintain good operability of medical devices while reducing putative side effects for the patient, a promising strategy is to tailor the surface properties of such devices as they critically dictate the tissue compatibility and the biofouling behavior. Indeed, those properties can be strongly improved by generating mucin coatings on such medical devices. However, using coatings on optical systems, e.g., contact lenses, comes with various challenges: here, the geometrical and optical characteristics of the lens may not be compromised by either the coating process or the coating itself. In this study, we show how mucin macromolecules can be attached onto the surfaces of rigid, gas permeable contact lenses while maintaining all critical lens parameters. We demonstrate that the generated coatings improve the surface wettability (contact angles are reduced from 105° to 40° and liquid film break-up times are increased from <1 s to 31 s) and prevent tribological damage to corneal tissue. Additionally, such coatings are highly transparent (transmission values above 98 % compared to an uncoated sample are reached) and efficiently reduce lipid deposition to the lens surface by 90 % but fully maintain the geometrical and mechanical properties of the lenses. Thus, such mucin coatings could also be highly beneficial for other optical systems that are used in direct contact with tissues or body fluids.

Distal Humeral Replacement in Patients with Primary Bone Sarcoma: The Functional Outcome and Return to Sports.

Distal humeral replacement (DHR) is a limb-salvage option for the endoprosthetic reconstruction of bone defects following the resection of a primary bone sarcoma. As primary bone sarcomas are only occasionally located around the distal humerus, there is a paucity of information regarding postoperative function, and patients' resumption of sporting activities. With advances in diagnostics and in surgical and oncological treatment leading to an increased patient life expectancy and higher quality of life, patients' functional outcome and return to sports activities are of increasing interest. Between 1997 and 2021, a total of 24 patients underwent DHR with a single-design modular implant at a tertiary sarcoma center. A total of 14 patients who died of their disease were excluded, leaving a study cohort of 10 patients, with a median age of 30 years on the day of surgery (IQR 20-37). At the last follow-up, after a median of 230 months (IQR 165-262), the median MSTS was 19 (IQR 13-24), the median TESS was 79 (IQR 66-87), the median SEV was 38% (IQR 24-53), the median TS was 6 (IQR 4-7), and the median WAS was 3 (IQR 1-8). Among the variables of gender, surgery on the dominant extremity, intraoperative nerve resection, extra-articular tumor resection, chemotherapy, radiotherapy, and revision surgeries, none were associated with a better/lower functional outcome score or return to sports activities. However, a higher level of sports performance prior to diagnosis (WAS > 10) was associated with a higher level of sports performance postoperatively (p = 0.044).

Machine learning approaches for biomolecular, biophysical, and biomaterials research.

A fluent conversation with a virtual assistant, person-tailored news feeds, and deep-fake images created within seconds-all those things that have been unthinkable for a long time are now a part of our everyday lives. What these examples have in common is that they are realized by different means of machine learning (ML), a technology that has fundamentally changed many aspects of the modern world. The possibility to process enormous amount of data in multi-hierarchical, digital constructs has paved the way not only for creating intelligent systems but also for obtaining surprising new insight into many scientific problems. However, in the different areas of biosciences, which typically rely heavily on the collection of time-consuming experimental data, applying ML methods is a bit more challenging: Here, difficulties can arise from small datasets and the inherent, broad variability, and complexity associated with studying biological objects and phenomena. In this Review, we give an overview of commonly used ML algorithms (which are often referred to as "machines") and learning strategies as well as their applications in different bio-disciplines such as molecular biology, drug development, biophysics, and biomaterials science. We highlight how selected research questions from those fields were successfully translated into machine readable formats, discuss typical problems that can arise in this context, and provide an overview of how to resolve those encountered difficulties.

Topography quantifications allow for identifying the contribution of parental strains to physical properties of co-cultured biofilms.

Most biofilm research has so far focused on investigating biofilms generated by single bacterial strains. However, such single-species biofilms are rare in nature where bacteria typically coexist with other microorganisms. Although, from a biological view, the possible interactions occurring between different bacteria are well studied, little is known about what determines the material properties of a multi-species biofilm. Here, we ask how the co-cultivation of two B. subtilis strains affects certain important biofilm properties such as surface topography and wetting behavior. We find that, even though each daughter colony typically resembles one of the parent colonies in terms of morphology and wetting, it nevertheless exhibits a significantly different surface topography. Yet, this difference is only detectable via a quantitative metrological analysis of the biofilm surface. Furthermore, we show that this difference is due to the presence of bacteria belonging to the 'other' parent strain, which does not dominate the biofilm features. The findings presented here may pinpoint new strategies for how biofilms with hybrid properties could be generated from two different bacterial strains. In such engineered biofilms, it might be possible to combine desired properties from two strains by co-cultivation.

Machine Learning Approach to Analyze the Surface Properties of Biological Materials.

Similar to how CRISPR has revolutionized the field of molecular biology, machine learning may drastically boost research in the area of materials science. Machine learning is a fast-evolving method that allows for analyzing big data and unveiling correlations that otherwise would remain undiscovered. It may hold invaluable potential to engineer novel functional materials with desired properties, a field, which is currently limited by time-consuming trial and error approaches and our limited understanding of how different material properties depend on each other. Here, we apply machine learning algorithms to classify complex biological materials based on their microtopography. With this approach, the surfaces of different variants of biofilms and plant leaves can not only be distinguished but also correctly classified according to their wettability. Furthermore, an importance ranking provided by one of the algorithms allows us to identify those surface features that are critical for a successful sample classification. Our study exemplifies how machine learning can contribute to the analysis and categorization of complex surfaces, a tool, which can be highly useful for other areas of materials science, such as damage assessment as well as adhesion or friction studies.

The Bateman-Type Soft Tissue Reconstruction around Proximal or Total Humeral Megaprostheses in Patients with Primary Malignant Bone Tumors-Functional Outcome and Endoprosthetic Complications.

We aimed to evaluate the functional outcome and endoprosthetic complications following the Bateman-type soft tissue reconstruction around proximal or total humeral replacements in patients undergoing resection of a primary malignant bone tumor. Between September 2001 and December 2018, a total of 102 patients underwent resection of a primary malignant bone tumor and subsequent reconstruction with a modular humeral megaprosthesis in our department. Fifteen (15%) of these patients underwent a Bateman-type soft tissue reconstruction and were included in this retrospective study. The median Musculoskeletal Tumor Society (MSTS) score was 21, the median Toronto Extremity Salvage Score (TESS) was 70, and the median American Shoulder and Elbow Surgeons (ASES) score was 72. Fifty-three percent (8/15) of all patients required a revision surgery after a median time of 6 months. There were 2 soft tissue failures, 3 infections and 3 tumor recurrences. The revision-free implant survivorship amounted to 53% (95% confidence interval (CI) 28-81) after 1 year and 47% (95% CI 22-73) at last follow-up. The Bateman-type reconstruction is a feasible option for soft tissue reconstruction but functional outcome is overall limited and the risk for revision surgery within the first postoperative year is high.

Periprosthetic Stress Shielding of the Humerus after Reconstruction with Modular Shoulder Megaprostheses in Patients with Sarcoma.

(1) Background: Modular megaprosthetic reconstruction using a proximal humerus replacement has emerged as a commonly chosen approach after bone tumor resection. However, the long-term risk for revision surgery is relatively high. One factor that might be associated with mechanical failures is periprosthetic osteolysis around the stem, also known as stress shielding. The frequency, potential risk factors, and the effect on implant survival are unknown. (2) Methods: A retrospective single-center study of 65 patients with sarcoma who underwent resection of the proximal humerus and subsequent reconstruction with a modular endoprosthesis. Stress shielding was defined as the development of bone resorption around the prosthesis stem beginning at the bone/prosthesis interface. The extent of stress shielding was measured with a new method quantifying bone resorption in relation to the intramedullary stem length. All patients had a minimum follow-up of 12 months with conventional radiographs available and the median follow-up amounted to 36 months. (3) Results: Stress shielding was observed in 92% of patients (60/65). The median longitudinal extent of stress shielding amounted to 14% at last follow-up. Fifteen percent (10/65) showed bone resorption of greater than 50%. The median time to the first radiographic signs of stress shielding was 6 months (IQR 3-9). Patients who underwent chemotherapy (43/65) showed a greater extent of stress shielding compared to those without chemotherapy. Three percent (2/65) of patients were revised for aseptic loosening, and one patient had a periprosthetic fracture (1/65, 1.5%). All these cases had >20% extent of stress shielding (23-57%). (4) Conclusions: Stress shielding of the proximal humerus after shoulder reconstruction with modular megaprosthesis is common. It occurs within the first year of follow-up and might be self-limiting in many patients; however, about one third of patients shows progression beyond the first year. Still, mechanical complications were rare, but stress shielding might be clinically relevant in individual cases. The extent of stress shielding was increased in patients who underwent perioperative chemotherapy. Stress shielding can be quantified with an easy method using the stem length as a reference.

Prevalence of Musculoskeletal Diseases of the Upper Extremity Among Dental Professionals in Germany.

OBJECTIVE: Although many findings on occupational musculoskeletal complaints are available from American and European dentists, the corresponding data from Germany are still scarce. Therefore, the aim of this study was to provide additional information on the prevalence of and risk factors for musculoskeletal disorders of the upper extremity, particularly the shoulder in this specific population. METHODS: A written survey was carried out among 600 dentists in the state of North Rhine-Westphalia, Germany. Questionnaire items included physical and psychosocial workload, general health, and the occurrence of musculoskeletal symptoms during the previous 12 months that led to sick leave and medical care according to a modified version of the Nordic Musculoskeletal Questionnaire (NMQ). Regression analysis was used to evaluate relevant risk factors for severe musculoskeletal disorders. RESULTS: A total of 229 dentists were participated in the study (response rate 38%). Overall, 92.6% of the participants had already suffered from musculoskeletal symptoms in at least one body region. Symptoms were mostly reported in the neck (65.1%) and in the shoulder (58.1%). Limitations in daily activities were experienced by 15.9% due to neck pain and by 15.4% due to shoulder pain. Medical care was sought by 23.7% because of neck pain and by 21.1% due to shoulder pain. Risk factors for symptoms in the upper extremity regions were gender (female), increased physical load, and numerous comorbidities. CONCLUSION: There is a high prevalence of musculoskeletal disorders among dentists. Suitable interventions are therefore needed to prevent musculoskeletal diseases and pain among dental professionals, with particular attention to female dentists.