Indole-3-pyruvate: Analysis and Control of Tautomerism and Reactivity.

It is well-known in biochemistry that structure confers function, meaning that chemical structural elucidation is critical to truly understanding the function of a given metabolite. Indole-3-pyruvate (IPyA) exists in an equilibrium between the keto and enol tautomeric forms. IPyA is suggested to play a role in immune function; however, determining whether the tautomeric forms function differently can only be studied if an analytical method is capable of distinguishing between the two forms. Herein, we describe the use of UHPLC-HRMS to gain insight into the physical variables that govern IPyA tautomer equilibrium, reactivity, and detection limit. We use hydrogen-deuterium exchange (HDX) to identify enol and keto peaks, and we show that tautomers exhibit a valley of fronting followed by a tailing peak shape (though separation is still attainable) and identical MS/MS spectra. We observed drastically different ratios of keto and enol forms in different solvents, which is an important consideration for in vitro studies. IPyA was found to be highly unstable with accelerated reactivity in peroxides. Through in vitro reactivity studies, IPyA produced a myriad of known and unknown metabolites via nonenzymatic processes, many of which were mapped in vivo via the analysis of human plasma. Finally, we show that vitamin C (ascorbic acid) can slow this reactivity and enable sensitive detection in whole blood.

The projected increase of vertebral osteomyelitis in Germany implies a demanding challenge for future healthcare management of aging populations.

PURPOSE: Since an increase in the occurrence of native vertebral osteomyelitis (VO) is expected and reliable projections are missing, it is urgent to provide a reliable forecast model and make it a part of future health care considerations. METHODS: Comprehensive nationwide data provided by the Federal Statistical Office of Germany were used to forecast total numbers and incidence rates (IR) of VO as a function of age and gender until 2040. Projections were done using autoregressive integrated moving average model on historical data from 2005 to 2019 in relation to official population projections from 2020 to 2040. RESULTS: The IR of VO is expected to increase from 12.4 in 2019 to 21.5 per 100,000 inhabitants [95% CI 20.9-22.1] in 2040. The highest increase is predicted in patients over 75 years of age for both men and women leading to a steep increase in absolute numbers, which is fourfold higher compared to patients younger than 75 years. While the IR per age group will not increase any further after 2035, the subsequent increase is due to a higher number of individuals aged 75 years or older. CONCLUSIONS: Our data suggest that increasing IR of VO will seriously challenge healthcare systems, particularly due to demographic change and increasing proportions of populations turning 75 years and older. With respect to globally fast aging populations, future health care policies need to address this burden by anticipating limitations in financial and human resources and developing high-level evidence-based guidelines for prevention and interdisciplinary treatment.

Conflicting effects of recombination on the evolvability and robustness in neutrally evolving populations.

Understanding the benefits and costs of recombination under different scenarios of evolutionary adaptation remains an open problem for theoretical and experimental research. In this study, we focus on finite populations evolving on neutral networks comprising viable and unfit genotypes. We provide a comprehensive overview of the effects of recombination by jointly considering different measures of evolvability and mutational robustness over a broad parameter range, such that many evolutionary regimes are covered. We find that several of these measures vary non-monotonically with the rates of mutation and recombination. Moreover, the presence of unfit genotypes that introduce inhomogeneities in the network of viable states qualitatively alters the effects of recombination. We conclude that conflicting trends induced by recombination can be explained by an emerging trade-off between evolvability on the one hand, and mutational robustness on the other. Finally, we discuss how different implementations of the recombination scheme in theoretical models can affect the observed dependence on recombination rate through a coupling between recombination and genetic drift.

Projections From Surgical Use Models in Germany Suggest a Rising Number of Spinal Fusions in Patients 75 Years and Older Will Challenge Healthcare Systems Worldwide.

BACKGROUND: Spinal fusion is a well-established procedure in the treatment of degenerative spinal diseases. Previous research shows that the use of this operative treatment has been growing in recent decades in industrialized countries and has become one of the most cost-intensive surgical procedures. It seems that in some countries such as Germany-with its large, industrialized, European population-this increase is mainly driven by demographic changes with low fertility rates, increasing life expectancy, and an aging population. Based on current projections, however, Germany faces a population trend that many other countries are likely to follow within a few decades. An increasingly shrinking and aging working population may eventually put the healthcare system under enormous pressure, with greater demands for spinal fusions and associated higher costs. Thus, we aimed to provide reliable projections regarding the future demand for posterior spinal fusion procedures including age- and gender-related trends up to 2060, which will be necessary for future resource planning and possible improvements in actual treatment strategies. QUESTIONS/PURPOSES: (1) How is the use of posterior spinal fusions in Germany expected to change from 2019 through 2060, if currents trends continue? (2) How is the use of posterior spinal fusions in Germany expected to change depending on patients' age and gender during this time period? METHODS: Comprehensive nationwide data provided by the Federal Statistical Office, the official institution for documenting all data on operations and procedures performed in Germany, were used to quantify posterior spinal fusion rates as a function of calendar year, age, and gender. Because there is a lack of evidence regarding future trends in the use of posterior spinal fusions, an autoregressive integrated moving average model on historical procedure rates from 2005 to 2019 in relation to official population projections from 2020 to 2060 was chosen to forecast future absolute numbers and incidence rates of this procedure in Germany. Long-term forecasting is more prone to unexpected disruptions than forecasting over short-term periods; however, longer spans facilitate estimates of how trends may challenge future healthcare systems if those trends continue, and thus are useful for research and planning. RESULTS: The incidence rate of posterior spinal fusion was projected to increase by approximately 83% (95% CI 28% to 139%) to 102% per 100,000 inhabitants (95% CI 71% to 133%) in 2060, with a 1.3-fold higher rate of women undergoing surgery in terms of absolute numbers. The highest increase identified by the model occurred in patients 75 years and older with 38,974 (95% CI 27,294 to 50,653) posterior spinal fusions in 2060, compared with 14,657 in 2019. This trend applied for both women and men, with a 246% (95% CI 138% to 355%) increase in the total number of posterior spinal fusions for women 75 years and older and a 296% (95% CI 222% to 370%) increase for men 75 years and older. At the same time, posterior spinal fusions in all age groups younger than 55 years were projected to follow a constant or even negative trend up to 2060. CONCLUSION: Our findings suggest that increasing use of posterior spinal fusion, particularly in patients 75 years and older, will challenge healthcare systems worldwide if current trends persist. This study may serve as a model for many other industrialized countries facing similar demographic and procedure-specific developments in the future. This emphasizes the need to focus on frailty research as well as appropriate financial and human resource management. Effective perioperative medical management, multidisciplinary treatment, and interinstitutional protocols are warranted, especially in older patients as we attempt to manage these trends in the future. LEVEL OF EVIDENCE: Level III, economic and decision analysis.

Mid-term outcome following radial head arthroplasty in acute trauma: risk factors for poor outcome.

BACKGROUND: The aims of this study were to evaluate the outcomes of a single type of radial head implant in a large cohort of patients at mid-term follow-up and to determine the associated risk factors for inferior functional outcomes. METHODS: We performed a retrospective follow-up assessment of 65 patients (33 women and 32 men; mean age, 53.3 years [range, 22-81 years]) who underwent radial head arthroplasty (RHA) for acute trauma between 2012 and 2018, after a minimum follow-up period of 3 years. The Mayo Elbow Performance Score, Oxford Elbow Score, Disabilities of the Arm, Shoulder and Hand score, and Mayo Modified Wrist Score were evaluated, and all available radiographs were analyzed. All complications and revision procedures were assessed. Bivariate and multivariate regression analyses were performed to identify potential risk factors for a poor outcome following RHA. RESULTS: After an average follow-up period of 4.1 years (range, 3-9.4 years), the mean Mayo Elbow Performance Score was 77.2 (standard deviation [SD], 18.9); mean Oxford Elbow Score, 32.0 (SD, 10.6); mean Mayo Modified Wrist Score, 74.6 (SD, 13.7); and mean Disabilities of the Arm, Shoulder and Hand score, 29.0 (SD, 21.2). Average range of motion measured 10° (SD, 15°) in extension, 125° (SD, 14°) in flexion, 81° (SD, 14°) in pronation, and 63° (SD, 24°) in supination. The overall complication and reoperation rates were 38.5% and 30.8%, respectively, with severe elbow stiffness being the most common reason for revision. Patient age >50 years, the use of an external fixator, the presence of accompanying medial collateral ligament injuries, and the development of higher-grade osteoarthritis were associated with a poor outcome. CONCLUSION: Satisfactory medium-term outcomes can be achieved using a monopolar, long-stemmed RHA in patients with acute trauma. However, complication and revision rates are high, frequently leading to inferior outcome scores. Additionally, a higher patient age, the use of an external fixator, the presence of accompanying medial collateral ligament injuries, and the occurrence of higher-grade osteoarthritis were associated with a poor outcome; these factors should raise awareness by the treating trauma surgeon.

Arthroscopic Bankart repair: how many knotless anchors do we need for anatomic reconstruction of the shoulder?-a prospective randomized controlled study.

PURPOSE: The optimal strategy for surgical repair of traumatic anterior shoulder instability remains controversial. While several study groups have reported that the clinical and radiological outcomes of arthroscopic procedures performed with two anchors are not fully adequate, these conclusions are not supported by the findings published in other studies. A prospective randomized study was conducted to compare the structural and clinical outcomes of surgical procedures involving two vs. three anchors. METHODS: Patients who underwent arthroscopic Bankart repair were randomly assigned to either Group I, which underwent procedures involving two double-loaded 3.5-mm knotless anchors, or Group II, which underwent procedures involving three single-loaded 2.9-mm knotless anchors. All patients underwent bilateral MRI assessments at a minimum of 12 months and clinical assessment at a minimum of 24 months postoperatively. To evaluate the reconstruction of the labral capsular ligamentous complex (LCLC), the labrum-glenoid height index (LGHI), restored labral height (LH), and labral slope (LS) were measured for both shoulders. For clinical assessment, the redislocation rate and functional outcome scores (Constant score (CS), American Shoulder and Elbow Surgeon score (ASES), Walch Duplay score (WDS), and Rowe score (RS)) were evaluated at follow-up visits. RESULTS: Bankart repair with two knotless anchors showed lower values for anterior reconstruction of the LCLC compared to the uninjured contralateral shoulder. Likewise, significant differences were noted when comparing these measurements to those from patients who underwent reconstruction with three anchors. No differences were demonstrated with regard to the reconstruction of the inferior LCLC. Clinical assessment showed good to excellent results in both groups. In total, three patients experienced redislocation of the shoulder: two in group I and one in group II. No significant differences were found with respect to clinical outcomes and redislocation rates. CONCLUSION: Bankart repair with both two and three knotless anchors results in effective anatomical reconstruction of the labral capsular ligamentous complex. Although the two-anchor technique yields significantly lower values for the anterior portion compared with the contralateral side, none of these differences reach clinical relevance as per our original definition.

Coronoid tip fractures in terrible triad injuries can be safely treated without fixation.

INTRODUCTION: The optimal treatment of terrible triad injuries of the elbow (TTI) remains topic of ongoing discussion. The aim of this study was to determine whether different treatment strategies for coronoid tip fractures in terrible triad injuries influences the clinical and radiological results in a mid-term follow-up. METHODS: A total of 62 patients with surgical treatment of a TTI including a coronoid tip fracture (37 women, 25 men; mean age, 51 years) were available for follow-up assessment after an average of 4.2 years (range 24-110 months). Thirteen patients had O'Driscoll 1.1 and 49 O'Driscoll 1.2 coronoid fractures, of which 26 were treated with and 36 without fixation. Range of motion, the Mayo Elbow Performance Score (MEPS), Oxford Elbow Score (OES), and Disabilities of the Arm, Shoulder and Hand (DASH) score as well as grip strength were evaluated. Radiographs were analyzed for all participants. RESULTS: No significant benefit in outcome variables could be detected between patients, whose coronoid had been fixed, compared to patients without fixation of the coronoid. In the coronoid fixation group, patients had mean outcome scores of 81.5 ± SD 19.1 (range 35-100) for MEPS, 31.0 ± SD 12.5 (range 11-48) for OES and 27.7 ± SD 23 (range 0-61) for DASH score, while in the no-fixation group, mean MEPS was 90.8 ± SD 16.5 (range 40-100), mean OES was 39.0 ± SD 10.4 (range 16-48) and mean DASH score was 14.5 ± SD 19.9 (range 0-48). Mean range of motion was 116° ± SD 21° (range 85-140°) versus 124° ± SD 24° (range 80-150°) in extension-flexion and 158° ± SD 23° (range 70-180°) versus 165° ± SD 12° (range 85-180°) in pronation-supination. Overall complication rate was 43.5% and revision rate was 24.2%, with no significant differences between both groups. Suboptimal results were more frequently seen in patients who had degenerative or heterotopic changes on their latest radiograph. CONCLUSIONS: Sufficient elbow stability and good outcomes can be achieved in most patients with TTI and coronoid tip fractures. Although some bias in treatment allocation and group heterogeneity cannot be completely omitted, our analysis detected no significant benefit in outcome when the coronoid tip fracture has been fixed compared to patients with non-fixed coronoid tip. Therefore, we would suggest a no-fixation approach for coronoid tip fractures as primary treatment in TTI of the elbow. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Value of closed suction drainage in arthroscopic and minimally invasive surgery of the ankle joint: a prospective randomised study.

INTRODUCTION: Closed suction drainage is an established procedure in arthroscopic surgery. It is intended to reduce the retention of wound and irrigation fluids, which form the basis for postoperative swelling, pain, and infection. However, currently, there is no scientific review of the actual benefit of this procedure. METHODS: Between 2020 and 2021, 84 patients (53 males, 31 females; mean age: 42 years) were prospectively randomised into this study. The patients underwent arthroscopic surgery of the ankle joint with (group A) or without (group B) insertion of a closed suction drain (42 patients per group). Assessments included upper ankle swelling using the figure-of-eight-20 method, pain preoperatively and 48 h postoperatively, and unexpected events within 6 weeks postoperatively. RESULTS: The measurements performed 48 h postoperatively showed a mean circumferential increase of 1.38 cm (1.48 and 1.28 cm in groups A and B, respectively; p > 0.05) in all patients. The mean pain at rest, assessed using the visual analogue scale (maximum 10 points), was 2.7 and 2.4 in groups A and B, respectively (p > 0.05). Overall, two minor complications occurred: residual swelling in group A and persistent limitation of movement in group B. The average length of hospital stay was 2.4 days (p > 0.05). CONCLUSIONS: Based on the available data, the routine insertion of a closed suction drainage at the upper ankle does not offer any objective benefit and must be considered obsolete. From both a medical and an economic point of view, the decision to conduct this procedure should be justified on an individual basis. LEVEL OF EVIDENCE: Level I, prospective randomised trial.

Tissue sampling is non-inferior in comparison to sonication in orthopedic revision surgery.

BACKGROUND: The aim of this study was to assess the role of sonication fluid cultures in detecting musculoskeletal infections in orthopedic revision surgery in patients suspected of having peri-prosthetic joint infection (PJI), fracture-related infections (FRI), or postoperative spinal implant infections (PSII). METHODS: Between 2016 and 2019, 149 cases with a data set including sonication fluid cultures and tissue specimen and histological analysis were included. Accuracy of each diagnostic tool as well as the influence of antibiotic therapy was analyzed. Pathogens identified in the sonication cultures and in the associated tissue samples were compared based on the matching of the antibiograms. Therapeutic benefits were then assessed. RESULTS: Of 149 cases, 43.6% (n = 65) were identified as PJI, 2.7% (n = 4) as FRI, 12.8% (n = 19) as PSII, 6.7% (n = 10) as aseptic non-union, and 34.2% (n = 51) as aseptic implant loosening. The sensitivity and specificity of tissue and synovial specimens showed no significant difference with respect to sonication fluid cultures (sensitivity/specificity: tissue: 68.2%/96.7%; sonication fluid cultures: 60.2%/98.4%). The administration of antibiotics over 14 days prior to microbiological sampling (n = 40) resulted in a lower sensitivity of 42.9% each. Histological analysis showed a sensitivity 86.3% and specificity of 97.4%. In 83.9% (n = 125) of the cases, the results of sonication fluid cultures and tissue specimens were identical. Different microorganisms were found in only four cases. In 17 cases, tissue samples (n = 5) or sonication (n = 12) were false-negatives. CONCLUSION: Sonication fluid culture showed no additional benefit compared to conventional microbiological diagnostics of tissue and synovial fluid cultures. Preoperative administration of antibiotics had a clearly negative effect on microbiologic test accuracy. In over 83.9% of the cases, sonication fluid and tissue cultures showed identical results. In the other cases, sonication fluid culture did not further contribute to the therapy decision, whereas other factors, such as fistulas, cell counts, or histological analysis, were decisive in determining therapy.

Comminuted AO-C3 fractures of the patella: good outcome using anatomically contoured locking plate fixation.

PURPOSE: The treatment of comminuted patellar fractures remains a challenge for orthopedic surgeons. The aim of this study was to assess the clinical, functional, and radiological outcome after treatment of comminuted patellar fractures using an anatomically contoured plating system. METHODS: Between January 2015 and December 2019 (5 years), 29 patients with complex C3 fractures according to AO classification (18 female, 11 male; mean age: 53 years) were treated using an anatomically contoured plating system (patella SuturePlate™, Arthrex®, Naples, USA). Indication for surgery was based on instability and/or initial fragment dislocation (> 2 mm). After a minimum follow-up of 12 months, patients were examined using a standardized clinical examination and functional outcome was assessed using specific knee scores (Lysholm, WOMAC, IKDC, Kujala, and Tegner score). In addition, complications were recorded and all available radiographs were evaluated regarding osteoarthritis and reduction quality. RESULTS: All patients returned for follow-up investigation after an average of 19 months (range: 12-48 months). A mean range of motion (ROM) of 131° (range: 100-150) was recorded. Overall good functional outcome parameters could be reported, with a mean Lysholm score of 84.7 (range: 100-45), a WOMAC of 5.1 (range: 0-19.2), a Kujala scale of 85.5 (range: 100-48), an IKDC of 76.6 (range: 100-44.8), and a Tegner score of 4.3 (range: 10-3) with a difference of 0.62 to pre-operative. Patient satisfaction was rated 8.4 (range: 4-10) using a VAS. No loss of reduction, mechanical failure, or implant complications were detected. Radiological follow-up showed no evidence of relevant post-traumatic retropatellar osteoarthritis. In 7 cases, implants were removed due to subjective mechanical irritation. CONCLUSION: Anatomically contoured patellar plates allow secure fixation of the fracture fragments even in comminuted cases. Especially when tension-band wiring is prone to early failure, locking plate fixation represents a viable option leading to good functional results and low complication rates.

Proximal ulna non-union: treatment concept and postoperative outcome.

PURPOSE: Non-union of the proximal ulna is a serious complication after surgical treatment of olecranon and complex elbow fractures, frequently leading to poor functional outcome. To date, there is a lack of data regarding optimal treatment strategies and functional outcome parameters after surgical revision. METHODS: From 02/2010 to 12/2018, 31 patients undergoing surgical treatment of proximal ulna non-union could be included. Follow-up period was seven years (SD 2.5 years). All patients were clinically assessed using a clinical assessment tool set and standard elbow scores (MEPS, OES, DASH score). All complications and unplanned revision surgeries were recorded and all radiographic material was analyzed. RESULTS: Initial non-union procedures were performed at an average of 6.6 months (SD 3 months) after the index procedures. Those included the use of autologous spongiosa graft in all patients and concomitant compression re-osteosynthesis in 28 patients. Radiological consolidation was achieved in all patients. Overall, patients achieved a good to fair functional outcome with Mayo elbow performance score measuring 78.5 (SD 9.1), DASH score 34.7 (SD 14.4), and Oxford elbow score 31.2 (SD 6.6) points. Initial malreduction/implant-malposition could be identified as a main reason for the occurrence of the non-union. Furthermore, inferior postoperative outcome was detected in patients > 60 years and BMI > 30 kg/m2. CONCLUSION: Using a standardized protocol, bony union and acceptable functional outcomes can be achieved in proximal ulna non-unions. However, surgeons should be aware of potential risk factors and proper initial fracture reduction as key to achieve sufficient bone healing.

Superiority of upper ankle arthrodesis over total ankle replacement in the treatment of end-stage posttraumatic ankle arthrosis.

PURPOSE: Surgical treatment of end-stage posttraumatic upper ankle arthrosis is challenging. Highly variable revision rates have been reported with total ankle arthroplasty (TAA) of the upper ankle joint. The aim of this retrospective study was to compare revision rates with tibiotalar arthrodesis (TTA) and TAA with a prosthesis to determine the superior treatment approach. METHODS: Data for 148 patients (96 males and 52 females) with end-stage posttraumatic upper ankle arthrosis-including 88 treated with TTA and 60 with TAA between 2008 and 2013, with a mean follow-up of 59 months-were analysed. Bone fusion was confirmed by x-ray radiography and computed tomography. RESULTS: The overall revision rate was 28%; the rate was higher with TAA (42%) than with TTA (18%). The TAA group showed an increase in revisions from 12- to 24-month postsurgery. The most common cause of revision in the TAA group was cysts (20%), and the most frequent reason for revision was nonunion (8%). Mean American Orthopaedic Foot and Ankle Society (AOFAS) and Foot and Ankle Outcome (FAO) scores in all patients were 55.5 and 53.1, respectively, with no significant difference between the TTA and TAA groups (p > 0.05). In nine cases (15%) the prosthesis was explanted or converted to TTA. TAA patients who underwent conversion to TTA had worse outcomes (AOFAS score = 39; FAO score = 35.29). CONCLUSION: TAA is associated with a high rate of revisions, especially from the 2nd year postsurgery. Therefore, TTA is the treatment of choice for end-stage posttraumatic upper ankle arthrosis. Level of evidence Level III, comparative series.

Treatment of grossly dislocated supracondylar humerus fractures after failed closed reduction: a retrospective analysis of different surgical approaches.

INTRODUCTION: The supracondylar humerus fracture (SCHF) is one of the most common pediatric injuries. Highly displaced fractures can be very challenging. If closed reduction fails, the therapy algorithm remains controversial. MATERIALS AND METHODS: In total, 41 patients (21 boys and 20 girls) with irreducible Gartland type III SCHF, treated with open reduction through three different approaches and cross-pin fixation, were retrospectively evaluated. The mean follow-up was 46 months (min.: 12, max.: 83, SD: 23.9). The Mayo elbow performance score (MEPS) as well as the quick disabilities of arm, shoulder and hand (qDASH) score were used to assess the functional outcome. Baumann's angle and the anterior humeral line (AHL, Roger's line) were obtained from follow-up radiographs. Time to surgery, postoperative nerve-palsy, rate of revision surgery, and complication rate were examined. RESULTS: Two revision surgeries were reported. One due to inadequate reduction and one due to secondary loss of reduction. In this context, the AHL was a sufficient tool to detect unsatisfactory reduction. According to the MEPS the functional outcome was excellent (> 90) in 37/41 patients and good (75-89) in 4/41 at the final visit. Fair or poor results were not documented. The qDASH score was 1.8 (min.: 0, max.: 13.6, SD: 3.4). There were no significant differences between the utilized surgical approaches. An iatrogenic injury of the ulnar nerve was not reported in any case. Overall, one heterotopic ossification without impairment of the range of motion and one preliminary affection of the radial nerve were documented. CONCLUSION: In the rare case of an irreducible SCHF, an anatomical reduction can be achieved by open approaches with excellent functional outcome and a high grade of patient satisfaction. All described open approaches can be utilized with a high safety-level.

The projected volume of primary and revision total knee arthroplasty will place an immense burden on future health care systems over the next 30 years.

PURPOSE: Total knee arthroplasty (TKA) rates have increased substantially in the recent decades worldwide, with Germany being one of the leading countries in the prevalence of TKA. The aim of this study was to provide an overview of treatment changes during the last decade and to project the expected burden of primary and revision TKA (rTKA) for the next 30 years. METHODS: Comprehensive nationwide data from Germany was used to quantify primary and revision TKA rates as a function of age and gender. Projections were performed with use of a Poisson regression models and a combination of exponential smoothing and autoregressive integrated moving average models on historical procedure rates in relation to official population projections from 2020 to 2050. RESULTS: The incidence rate of primary TKAs is projected to increase by around 43% to 299 per 100,000 inhabitants [95% CI 231-368], leading to a projected total number of 225,957 primary TKAs in 2050 (95% CI 178,804-276,442). This increase has been related to a growing number of TKA performed in male patients, with the highest increase modelled in patients between 50 and 65 years of age. At the same time, the annual total number of revision procedures is forecast to increase even more rapidly by almost 90%, accounting for 47,313 (95% CI 15,741-78,885; IR = 62.7 per 100,000, 95% CI 20.8-104.5) procedures by 2050. Those numbers are primarily associated with a rising number of rTKAs secondary to periprosthetic joint infection (PJI). CONCLUSIONS: Using this country- specific forecast approach, a rising number of primary TKA and an even more rapidly growing number of rTKA, especially for PJI, has been projected until 2050, which will inevitably provide a huge challenge for the future health care system. As many other industrialized nations will face similar demographic and procedure-specific developments, these forecasts should be alarming for many health care systems worldwide and emphasize the tremendous need for an appropriate financial and human resource management in the future. LEVEL OF EVIDENCE: Level III, prognostic study, economic and decision analysis.

Epidemiology and Treatment of Radial Head Fractures: A Database Analysis of Over 70,000 Inpatient Cases.

PURPOSE: We aimed to study the epidemiology of radial head fractures within a single national registry database while analyzing trends in available treatments. METHODS: A retrospective analysis of data from 2007 to 2016 provided by a national inpatient database registry was performed using the International Classification of Diseases code for radial head fractures and associated German Procedure Classification (OPS) codes. All surgical interventions were evaluated according to fracture type, patient sex and age, and distribution differences over the last decade to detect changes in the treatment trends. The number of major revision procedures was identified and the revision burden for each procedure calculated. RESULTS: Overall, 70,118 radial head fractures were included, with the annual number rising over 20% during this period. Women were significantly older than men (peak incidence, 55-64 years vs 30-39 years) and more frequently injured (women-to-men, 1.3:1). Surgical interventions increased during the study period, with locking plate fixation of comminuted fractures and radial head arthroplasty (RHA) becoming increasingly performed while radial head resections decreased. The revision burden differed significantly between the fixation techniques, with an increased occurrence of RHA revision procedures more recently. CONCLUSIONS: The data show a higher number and incidence of surgical procedures, especially for comminuted radial head fractures over the study period. Open reduction and internal fixation remains the most frequently used option, with the use of new fixation devices (eg, locking plates) increasing. The use of RHA more than doubled over the past 10 years while the number of radial head resections decreased. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic II.

Secondary reconstruction of chronic Achilles tendon rupture: flexor hallucis longus transfer versus plantaris longus augmentation.

INTRODUCTION: Chronic Achilles tendon rupture is primarily caused by degenerative processes of multifactorial origin. In addition to secondary repair (SR) with augmentation of the plantaris longus tendon, the transfer of the flexor hallucis longus tendon (FHL) to the calcaneus is a recognised reconstruction procedure. This paper aims to provide a direct comparison based on clinical scores and objectifiable strength measurements. METHODS: We analysed data for 60 patients (46 males and 14 females) with chronic Achilles tendon rupture, including 34 (mean age 57 years) treated with FHL and 26 (mean age 52 years) with SR between 2016 and 2020 (mean follow-up of 49 months). The follow-up included the American Orthopaedic Foot and Ankle Society Ankle-Hindfoot Scoring System (AOFAS-AH) and Visual Analogue Scale Foot and Ankle (VAS FA), the 12-item Short Form Survey (SF-12) and the objectifiable strength measurement using the dynamometer BIODEX®. Pre-existing gait disorders and permanent pain therapy led to exclusion. RESULTS: The mean AOFAS-AH was 87.8 points (FHL: 85.6, SR: 90.6), the mean VAS FA was 78.1 points (FHL: 73.7, SR: 83.6), the mean PCS was 48.2 points (FHL: 46.3, SR: 50.7) and the mean MCS was 54.1 points (FHL: 55.0, SR: 53.0). The maximum torque for plantar flexion was 56.7 Nm on average (FHL: 51.0, SR: 63.7). A total of seven (11.7%) wound infections requiring revision occurred (FHL: 4 (11.8%), SR: 3 (11.5%)). All measurements did not differ significantly between the groups (p > 0.05). CONCLUSION: The results of the study prove the equivalence of FHL and SR based on the clinical scores as well as on the strength measurement using BIODEX®. Nevertheless, a higher withdrawal because of morbidity with a tendency for prolonged incapacity to work in the FHL group has to be taken into account. The present work provides the basis for a prospective comparison in future studies.

Future burden of primary and revision hip arthroplasty in Germany: a socio-economic challenge.

INTRODUCTION: Total hip arthroplasty (THA) rates have increased dramatically in the recent decades worldwide, with Germany being one of the leading countries in the prevalence of THA. Simultaneously, a rising number of revision procedures is expected, which will put an enormous economic burden on future health care systems. METHODS: Nationwide data provided by the Federal Statistical Office of Germany were used to quantify primary and revision arthroplasty rates as a function of age and gender. Projections were performed with use of Negative Binomial and Poisson regression models on historical procedure rates in relation to population projections from 2020 to 2060. RESULTS: A 62% increase in the incidence rate of primary THAs is projected until 2060. At the same time, the annual total number of revision procedures is forecast to rise about 40% by the year 2060. The highest numbers of revision arthroplasties were calculated around year 2043. The greatest proportions of revision surgery will be observed in women and in those aged 70 years or older. The revision burden is projected to stabilize around 15% by 2060. CONCLUSIONS: The present projections allow a quantification of the increasing economic burden that (revision) THA will place on the German health care system in the upcoming decades. This study may serve as a model for other countries with similar demographic development as the country-specific approach predicts a substantial increase in the number of these procedures. This highlights the need for appropriate financial and human resource management in the future.

Mid-term clinical outcome comparison of long-stemmed monopolar osseointegrated and short-stemmed bipolar radial head prostheses.

INTRODUCTION: Comparative data to guide implant choice for radial head replacements are lacking. Here, we compared the clinical results achieved using two different types of radial head prostheses. METHODS: Data from patients with comminuted radial head fractures (n = 66), who underwent radial head arthroplasty with either short-stemmed bipolar (n = 31, Group 1: rHead Small Bone Innovations/USA) or monopolar long-stemmed osseointegrated rigidly fixed (n = 35, Group 2: MoPyC Tornier/France) prostheses, were retrospectively reviewed. Patients were followed-up for an average of 42 months (16-64 months). Range of elbow motion, elbow stability, grip strength, and visual analog scale (VAS) pain were measured, and functional outcome assessed using the Mayo Elbow Performance Score, the Disability of Arm, Shoulder and Hand questionnaire, and the Broberg-Morrey Score. Complications were analyzed and revision surgeries recorded. RESULTS: Most patients achieved good/excellent results for all assessed outcome variables, with no significant differences between the two implant groups; however, regardless of the prosthesis type, a mean extension deficit of 18.5° ± 1.7° remained at latest follow-up. Although complication and surgical revision rates were comparable (bipolar, 23%; monopolar, 18%), significantly more bipolar prostheses were explanted because of painful loosening (16% vs. 3%; p = 0.029). CONCLUSION: Good to excellent mid-term results for radial head arthroplasty of comminuted radial head fractures can be achieved using both a bipolar and a monopolar radial head implant; however, the monopolar implant may be preferable, as it had a lower rate of painful loosening. Extension deficit occurs regularly. LEVEL OF EVIDENCE: Level III Retrospective comparative treatment study.

Recombination and mutational robustness in neutral fitness landscapes.

Mutational robustness quantifies the effect of random mutations on fitness. When mutational robustness is high, most mutations do not change fitness or have only a minor effect on it. From the point of view of fitness landscapes, robust genotypes form neutral networks of almost equal fitness. Using deterministic population models it has been shown that selection favors genotypes inside such networks, which results in increased mutational robustness. Here we demonstrate that this effect is massively enhanced by recombination. Our results are based on a detailed analysis of mesa-shaped fitness landscapes, where we derive precise expressions for the dependence of the robustness on the landscape parameters for recombining and non-recombining populations. In addition, we carry out numerical simulations on different types of random holey landscapes as well as on an empirical fitness landscape. We show that the mutational robustness of a genotype generally correlates with its recombination weight, a new measure that quantifies the likelihood for the genotype to arise from recombination. We argue that the favorable effect of recombination on mutational robustness is a highly universal feature that may have played an important role in the emergence and maintenance of mechanisms of genetic exchange.

No functional differences in anatomic reconstruction with one vs. two suture anchors after non-simultaneous bilateral distal biceps brachii tendon rupture: a case report and review of the literature.

BACKGROUND: Surgical reattachment of the tendon is still the gold standard for ruptures of the distal biceps brachii tendon. Several fixation techniques have been described in the literature, with suture anchors being one of the most common fixation techniques. Currently, there is no data available on how many anchors are required for a safe and stable refixation. In this case report clinical data of a patient with non-simultaneous bilateral distal biceps tendon ruptures treated with a different number of suture anchors for each side (one vs. two) are demonstrated. CASE PRESENTATION: A 47-year-old factory worker suffered a rupture of the distal biceps tendon on both arms following two different occasions. The left side was fixed using a single suture anchor, while refixation on the right side was performed with two anchors. The patient was prospectively followed for one year. Functional outcome was assessed using the Andrews Carson Score (ACS), the Oxford Elbow Score (OES), and the Disabilities of Arm, Shoulder and Hand (DASH) Score after six, twelve, 24 and 48 weeks. Furthermore, an isokinetic strength measurement for flexion strength was performed after 24 and 48 weeks. After 48 weeks the patient presented with excellent functional outcome scores and no follow-up complications. During the follow-up period, no differences in the functional scores nor in the isokinetic flexion strength measurement could be detected. Furthermore, no radiological complications (like heterotopic ossifications) could be detected in the postoperative radiographs after one year. CONCLUSIONS: Anatomic reattachment of the distal biceps tendon is a successful operative treatment option for distal biceps tendon ruptures. Suture anchor fixation remains one of the most common techniques, as it allows fast surgery and provides good results with respect to range of motion (ROM) and functional scoring according to the current literature. However, the number of anchors required for a stable fixation remains unclear. As indicated by our presented case, we hypothesize, that there are no significant differences between a one-point or a two-point fixation. In the presented case report, no intraindividual differences between the usage of one versus two suture anchors were evident in the short-term follow-up.