Development of a test system to analyze different hip fracture osteosyntheses under simulated walking

The mechanical complications of osteosyntheses after hip fractures are previously investigated by mostly static or dynamic uniaxial loading test systems. However, the physiologic loading of the hip joint during a normal gait is a multiplanar, dynamic movement. Therefore, we constructed a system to test osteosyntheses for hip fractures under physiologic multiplanar loading representative of normal gait. To evaluate the testing system, 12 femora pairs were tested under 25,000 cycles with two standard osteosyntheses (Proximal Femoral Nail Antirotation/Gamma3 Nail). For angular movement, the varus collapse to cut out (proportional to(CO)) (proportional to(CO) = 4.8 degrees +/- 2.1 degrees for blade and proportional to(CO) = 7.8 degrees +/- 3.8 degrees for screw) was the dominant failure mode, and only slight rotational angle shifts (proportional to(Rot)) (proportional to(Rot) = 1.7 degrees +/- 0.4 degrees for blade and proportional to(Rot) = 2.4 degrees +/- 0.3 degrees for screw) of the femoral head around the implant axis were observed. Angular displacements in varus direction and rotation were higher in specimens reinforced with screws. Hence, the cut out model and the migration directions showed a distinction between helical blade and hip screw. However, there were no significant differences between the different implants. The new setup is able to create clinical failures and allows to give evidence about the anchorage stability of different implant types under dynamic gait motion pattern

Fractures' associated mortality risk in orthogeriatric inpatients: a prospective 2-year survey

Purpose!#!The most common osteoporotic fragility fractures are hip, vertebral and upper extremity fractures. An association with increased mortality is widely described with their occurrence. Fracture-specific associated death rates were determined in a 2-year follow-up for patients treated on an orthogeriatric ward. These were compared amongst each other, examined for changes with age and their impact on the relative mortality risk in relation to the corresponding population.!##!Methods!#!We assessed all patients that were treated in the course of a year on an orthogeriatric ward and suffered from the following injuries: hip (HF), vertebral (VF) and upper extremity fractures (UEF). In a 2-year follow-up it was possible to determine the month of death in the case of the patient's decease. Pairwise comparisons of the three fracture type death rates were performed through Cox-Regression. We stratified the fracture-dependent absolute mortality and age-specific mortality risk (ASMR) for age groups 71-80, 81-90 and 91-95.!##!Results!#!Overall, we assessed 240 patients with HF, 96 with VF and 127 with UEF over the span of a year. 1- and 2-year-mortality was: HF: 29.6% a.e. 42.9%, VF: 29.2% a.e. 36.5%, UEF: 20.5% a.e 34.6%. Pairwise comparisons of these mortality values revealed no significant differences. In association with HF and VF, we observed a significant increase of 2-year mortality for the oldest compared to the youngest patients (HF: 60.4% vs. 22.5%; p = 0.028) (VF 70% vs. 14.3%; p = 0.033). The analogue comparison for UEF revealed no relevant difference in age-dependent mortality (40.9% vs. 31.1%; p = 0.784). Common for all fracture types ASMR's were more elevated in the younger patients and decreased with higher age.!##!Conclusion!#!The fracture-related mortality in the 2-year follow-up was comparable. We observed a reduction of relative mortality risk in the oldest patients. While a direct influence of fracture on mortality must be supposed, we support the thesis of the fracture rather being an indicator of higher susceptibility of timely death

Synthese von 1,2,3,3,6,6-Hexamethyl-1-cyclohexen. Eine Umlagerungskaskade von C12H23+-Kationen

6-Chlor-2,6,7,7-tetramethyl-2-octen (4), das Prenylchlorid-Additionsprodukt an 2,3,3-Trimethyl-1-buten, geht bei Raumtemperatur in Gegenwart von Zinkchlorid und Chlorwasserstoff eine Cyclokondensation unter Bildung von 1,2,3,3,6,6-Hexamethyl-1-cyclohexen (1) ein. Der Reaktionsmechanismus wird durch die Isolierung intermediär auftretender fünfgliedriger Ringe und durch Kraftfeldrechnungen aufgeklärt

Early surgery? In-house mortality after proximal femoral fractures does not increase for surgery up to 48 h after admission

Purpose The economic cost linked to the increasing number of proximal femur fracture and their postoperative care is immense. Mortality rates are high. As early surgery is propagated to lower mortality and reduce complication rates, a 24-h target for surgery is requested. It was our aim to determine the cut-off for the time to surgery from admission and therefore establish a threshold at which the in-house mortality rate changes. Methods A retrospective single-center cohort study was conducted including 1796 patients with an average age of 82.03 years treated operatively for a proximal femoral fracture between January 2016 and June 2020. A single treatment protocol was performed based on the type of anticoagulant, surgery, and renal function. Patient data, surgical procedure, time to surgery, complications, and mortality were assessed. Results In-house mortality rate was 3.95%, and the overall complication rate was 22.7%. A prolonged length of hospital stay was linked to patient age and occurrence of complications. Mortality is influenced by age, number of comorbidities BMI, and postoperative complications of which the most relevant is pneumonia. The mean time to surgery for the entire cohort was 26.4 h. The investigation showed no significant difference in mortality rate among the two groups treated within 24 h and 24 to 48 h while comparing all patients treated within 48 h and after 48 h revealed a significant difference in mortality. Conclusions Age and number of comorbidities significantly influence mortality rates. Time to surgery is not the main factor influencing outcome after proximal femur fractures, and mortality rates do not differ for surgery up to 48 h after admission. Our data suggest that a 24-h target is not necessary, and the first 48 h may be used for optimizing preoperative patient status if necessary

The anterior impingement after mobile-bearing unicomparimental knee arthroplasty—a neglected problem. A clinical report of 14 cases

BACKGROUND: Mobile-bearing unicompartmental knee arthroplasty (MB-UKA) is a proven implant that has reliably delivered excellent results for decades. Based on the constrained implant design in MB-UKA, the occasional occurrence of anterior impingement should be expected. However, surprisingly, there are no clinical reports. METHODS: From 2016 to 2020, 14 patients with anterior medial knee pain were admitted to our arthroplasty center after MB-UKA implantation elsewhere. After taking the medical history and clinical examination, radiological imaging of the implant in at least 2 planes, including a whole-leg anteroposterior view, was performed. The “Knee Society Score (KSS)” and the “Knee Injury and Osteoarthritis Outcome Score (KOOS)” were recorded. Anterior impingement was diagnosed by reviewing the typical findings and specific exclusion of other diagnoses. RESULTS: The 14 patients showed a KSS of 46.6 and a KOOS of 51.5. The average pain level on the “Visual Analog Scale” was 7.8. The positioning of the implants showed consistently noticeable deviations from the standard recommendations. All 14 patients were treated by removing the MB-UKA and changing to a complete TKA. At the 12-month follow-up, the average Visual Analog Scale score was 1.8, and KOOS and KSS were 86 and 82, respectively. CONCLUSIONS: The potential risk of anterior impingement in MB-UKA can be assumed. Diagnosis requires a detailed collection of medical history and clinical details combined with accurate radiological imaging. The cause of anterior impingement in MB-UKA is multifactorial and refers in our small group to the sum of minor deviations in implant positioning compared to the general recommendations

The Role of a Primary Arthroplasty in the Treatment of Proximal Tibia Fractures in Orthogeriatric Patients

The total knee arthroplasty (TKA) is the gold standard for patients with an advanced symptomatic gonarthrosis. However, there are very few publications dealing with the primary TKA for patients with a proximal tibia fracture. In our retrospective study we evaluated 30 patients treated with a TKA for a proximal tibia fracture in our institution between 01/2008 and 12/2014. We collected the following statistical data from each patient: age, classification of the fracture (AO-classification), type of prosthesis used, length of the operation and hospitalization, and complications during the follow-up. We used the Knee Society Score (KSS) and the WOMAC score to evaluate the function. The Knee Society Score showed an average “general knee score” (KSS1) of 81.1 points and an average “functional knee score” (KSS2) of 74.5 points. The average WOMAC score was 78.6 points. Immediate postoperative mobilization with the possibility of a full-weight bearing is of crucial importance for the geriatric patients to maintain the mobility they had prior to the operation and reduce medical complications. Because of these advantages, the primary TKA seems to be a promising alternative to the ORIF of a proximal tibia fracture in the orthogeriatric patient

The role of a primary arthroplasty in the treatment of proximal tibia fractures in orthogeriatric patients

The total knee arthroplasty (TKA) is the gold standard for patients with an advanced symptomatic gonarthrosis. However, there are very few publications dealing with the primary TKA for patients with a proximal tibia fracture. In our retrospective study we evaluated 30 patients treated with a TKA for a proximal tibia fracture in our institution between 01/2008 and 12/2014. We collected the following statistical data from each patient: age, classification of the fracture (AO-classification), type of prosthesis used, length of the operation and hospitalization, and complications during the follow-up. We used the Knee Society Score (KSS) and the WOMAC score to evaluate the function. The Knee Society Score showed an average “general knee score” (KSS1) of 81.1 points and an average “functional knee score” (KSS2) of 74.5 points. The average WOMAC score was 78.6 points. Immediate postoperative mobilization with the possibility of a full-weight bearing is of crucial importance for the geriatric patients to maintain the mobility they had prior to the operation and reduce medical complications. Because of these advantages, the primary TKA seems to be a promising alternative to the ORIF of a proximal tibia fracture in the orthogeriatric patient

Accompanying injuries in tibial shaft fractures: how often is there an additional violation of the posterior malleolus and which factors are predictive? A retrospective cohort study

INTRODUCTION: An undislocated fracture of the posterior malleolus is a common concomitant injury in tibial shaft spiral fractures. Nevertheless, these accompanying injuries cannot always be reliably assessed using conventional X-rays. Thus, the aim of the study is to evaluate how often a fracture of the posterior malleolus occurs with tibial shaft fractures (AO:42A/B/C and AO:43A) and which factors—identifiable in conventional X-rays—are predictive. METHODS: Retrospective evaluation of X-ray and CT images revealed a total of 103 patients with low-energy tibial shaft fractures without direct joint involvement. Proximal fractures and fractures involving the knee were excluded. Basic data on injury, the trauma mechanism, the path of the fracture, bony avulsions of the posterior syndesmosis and the procedures performed were evaluated. RESULTS: Thirty-nine fractures were located in the middle third of the tibia, 64 in the distal third. In 65 cases, a spiral fracture (simple or wedge fracture) was found. In 31/103 fractures, an additional osseous avulsion of the posterior syndesmosis could be detected, 5 (16.1%) of them were not recognized preoperatively due to an absence of CT imaging. In three of these patients, a fracture of the posterior malleolus was only recognized postoperatively, and an additional surgery was necessary. The spiral fractures were classified in the a.p. X-ray according to their path from lateral proximal to medial distal (Type A) or from medial proximal to lateral distal (Type B). A Pearson chi-square test and Fisher’s exact test showed a highly significant accumulation of accompanying posterior malleolus fractures for type A fractures (p = 0.001), regardless of the location of the fracture. In addition, the fractures with involvement of the posterior malleolus had a significantly higher proportion in the fractures of the distal third (p = 0.003). There was no statistically significant relationship between the height of the fracture and the path of the fracture (type A or B). These two factors seem to be independent factors for participation of the posterior malleolus. CONCLUSION: In 40.6% of the tibial shaft fractures in the distal third, in 56.9% of the type A spiral fractures and in 67.6% of the type A fractures in the distal third, the ankle joint is involved with bony avulsion of the posterior syndesmosis, which is not always recognized in conventional X-rays. To avoid complications such as additional operations, instability and post-traumatic arthrosis, we recommend preoperative imaging of the ankle using CT for these fractures. LEVEL OF EVIDENCE: III, retrospective cohort study. TRAIL REGISTRATION NUMBER: DRKS00024536