Johannes Frank

Purpose There are numerous operative procedures to treat osteoarthritic changes or a significant instability of the distal radioulnar joint (DRUJ). The key problem of most methods is the destabilization of the forearm leading to secondary painful impingement between the radius and ulna, as well as a significant limitation of forearm rotation. The Aptis-Prosthesis designed by Scheker represents a complete substitute for the DRUJ. It is mostly used after the failure of various treatment options to solve the primary problems (arthritis, instability). We have used this type of prosthesis mostly after multiple operative treatments for more than 25 years. Methods In the following retrospective study, we analyzed the data of patients that received an Aptis-prosthesis between 2016 and 2021. We have implanted this prosthesis in 13 cases (11 female, 2 male). Routinely, we document the clinical outcome concerning range of motion (ROM), grip strength, and pain according to numeric rate scaling (NRS) after more than 12 months (month 12–24). In addition, complications, osseous changes, and the rate of loosening of the prosthesis were registered. Furthermore, DASH-Score and patients ‘ satisfaction were evaluated. Also—as with other implants—follow-up x-rays were performed. Results Removal or significant revision of any of the prostheses was not needed. The ROM was 68.1° ± 19.7° for pronation and 72.3° ± 20.9° for supination, grip strength amounted to 27.7 kg ± 11.0 kg equaling 83% of the contralateral side. NRS was 0 at rest and 1.2 (0–2) under weight-bearing. A lysis margin of the radial tap was noted in the radiological examination in 2 patients but without any signs of loosening. The DASH-Score added up to 31.8 ± 13.8 (13–55). All patients were satisfied or very satisfied having this implant. Conclusion The semiconstrained Aptis-prosthesis is a safe and efficient treatment option after failed DRUJ surgeries. It is striking that of the 20 implanted prostheses no significant revision or explantations were necessary over a period of 25 years.

For acute and chronic soft tissue infections, radical surgical debridement is required and is considered the gold standard, along with its immediate systemic antibiotic therapy. Treatment with local antibiotics and/or antibiotic-containing materials is commonly used as an additional tool in clinical practice. Spraying with fibrin and antibiotics is a newer technique that has been studied for some antibiotics. However, for gentamicin, data are not yet available on absorption, optimal application, antibiotic fate at the site and transfer of antibiotic into the blood. In an animal study involving 29 Sprague Dawley rats, 116 back wounds were sprayed with gentamicin using either gentamicin alone or one of two possible spray combinations of gentamicin and fibrin. Simultaneous application of gentamicin and fibrin via a spray system to soft tissue wounds resulted in significant antibiotic concentration over a long period of time. The technique is easy and cost-effective. The systemic crossover was significantly minimized in our study, which may have led to fewer side effects in patients. These results could lead to an improvement in local antibiotic therapy.

Objectives: The objective of this work was to evaluate the incremental value of MR angiography over plain radiographs and MRI for the differentiation of aneurysmal bone cysts (ABCs) from unicameral bone cysts (UBCs). Methods: Thirty-six juvenile patients with histologically secured primary ABCs or UBCs were included in this retrospective study. Two radiologists assessed all obtained images in a blinded fashion using a catalog of previously suggested imaging findings. A second readout with supplementary MR angiography images was performed after 8 weeks to prevent observer recall bias. Diagnostic accuracy parameters were calculated for individual imaging findings, and overall diagnostic accuracy and diagnostic confidence were assessed for all readouts. Receiver operating characteristic (ROC) curve comparison was used to determine the incremental value of MR angiography. Results: Of 16 imaging features, only abnormal vascularization in MR angiography provided sufficient diagnostic accuracy for the identification of ABCs. Other imaging features such as fluid–fluid levels and internal septations were insufficient for the differentiation of UBCs from ABCs. Availability of MR angiography images significantly increased diagnostic accuracy (94.4 vs 75.0% and 83.3 vs 69.4%, respectively, p < 0.05) and diagnostic confidence (4.5 vs 3.7, p < 0.05) of reading radiologists. Conclusion: The presence of arterial feeders in MR angiography can accurately discriminate primary ABCs from UBCs and increases the diagnostic accuracy and diagnostic confidence of reporting radiologists. Advances in knowledge: Radiographic differentiation of cystic bone lesions such as ABCs and UBCs remains challenging. We demonstrate that MR angiography provides incremental value and suggest inclusion in standard examination protocols.

Three-dimensional printing, especially fused filament fabrication (FFF), offers great possibilities in (bio-)medical applications, but a major downside is the difficulty in sterilizing the produced parts. This study evaluates the questions of whether autoclaving is a possible solution for FFF-printed parts and if the printer itself could be seen as an inherent sterilization method. In a first step, an investigation was performed on the deformation of cylindrically shaped test parts after running them through the autoclaving process. Furthermore, the inherent sterility possibilities of the printing process itself were evaluated using culture medium sterility tests. It could be shown that, depending on the needed accuracy, parts down to a diameter of 5–10 mm can still be sterilized using autoclaving, while finer parts suffer from major deformations. For these, inherent sterilization of the printer itself is an option. During the printing process, over a certain contact time, heat at a higher level than that used in autoclaving is applied to the printed parts. The contact time, depending on the printing parameters, is calculated using the established formula. The results show that for stronger parts, autoclaving offers a cheap and good option for sterilization after FFF-printing. However, the inherent sterility possibilities of the printer itself can be considered, especially when printing with small layer heights for finer parts.

Large bone defects are commonly treated by replacement with auto- and allografts, which have substantial drawbacks including limited supply, donor site morbidity, and possible tissue rejection. This study aimed to improve bone defect treatment using a custom-made filament for tissue engineering scaffolds. The filament consists of biodegradable polylactide acid (PLA) and a varying amount (up to 20%) of osteoconductive S53P4 bioglass. By employing an innovative, additive manufacturing technique, scaffolds with optimized physico-mechanical and biological properties were produced. The scaffolds feature adjustable macro- and microporosity (200–2000 µm) with adaptable mechanical properties (83–135 MPa). Additionally, controllable calcium release kinetics (0–0.25 nMol/µL after 24 h), tunable mesenchymal stem cell (MSC) adhesion potential (after 24 h by a factor of 14), and proliferation (after 168 h by a factor of 18) were attained. Microgrooves resulting from the 3D-printing process on the surface act as a nucleus for cell aggregation, thus being a potential cell niche for spheroid formation or possible cell guidance. The scaffold design with its adjustable biomechanics and the bioglass with its antimicrobial properties are of particular importance for the preclinical translation of the results. This study comprehensibly demonstrates the potential of a 3D-printed bioglass composite scaffold for the treatment of critical-sized bone defects.

Epoxyeicosatrienoic acids (EET) facilitate regeneration in different tissues, and their benefit in dermal wound healing has been proven under normal conditions. In this study, we investigated the effect of 11,12 EET on dermal wound healing in diabetes. We induced diabetes by i.p. injection of streptozotocin 2 weeks prior to wound creation on the dorsal side of the mouse ear. 11,12 EET was applied every second day on the wound, whereas the control groups received only solvent. Epithelialization was monitored every second day intravitally up to wound closure. Wounds were stained for VEGF, CD31, TGF-β, TNF-α, SDF-1α, NF-κB, and Ki-67, and fibroblasts were counted after hematoxylin-eosin stain on days 3, 6, 9, and 16 after wounding. After induction of diabetes, wounds closed on day 13.00 ± 2.20 standard deviation (SD). Local 11,12 ETT application improved wound closure significantly to day 8.40 ± 1.39 SD. EET treatment enhanced VEGF and CD31 expression in wounds on day 3. It also seemed to raise TNF-α level on all days investigated as well as TGF-β level on days 3 and 6. A decrease in NF-κB could be observed on days 9 and 16 after EET application. The latter findings were not significant. SDF-1α expression was not influenced by EET application, and Ki-67 was significantly less in the EET group on day 9 after EET application. The number of fibroblasts was significantly increased on day 9 after the 11,12 EET application. 11,12 EET improve deteriorated wound healing in diabetes by enhancing neoangiogenesis, especially in the early phase of wound healing. Furthermore, they contribute to the dissolution of the initial inflammatory reaction, allowing the crucial transition from the inflammatory to proliferative phase in wound healing.

Introduction: In an emergency department, the majority of pediatric trauma patients present because of minor injuries. The aim of this study was to evaluate temporal changes in age-related injury pattern, trauma mechanism, and surgeries in pediatric patients. Methods: This retrospective study included patients < 18 years of age following trauma from 01/2009 to 12/2018 at a level I trauma center. They were divided into two groups: group A (A: 01/2009 to 12/2013) and group B (B: 01/2014 to 12/2018). Injury mechanism, injury pattern, and surgeries were analyzed. As major injuries fractures, dislocations, and organ injuries and as minor injuries contusions and superficial wounds were defined. Results: 23,582 patients were included (58% male, median age 8.2 years). There was a slight increase in patients comparing A (n = 11,557) and B (n = 12,025) with no difference concerning demographic characteristics. Significant more patients (A: 1.9%; B: 2.4%) were admitted to resuscitation room, though the number of multiple injured patients was not significantly different. In A (25.5%), major injuries occurred significantly less frequently than in B (27.0%), minor injuries occurred equally. Extremity fractures were significantly more frequent in B (21.5%) than in A (20.2%), peaking at 8–12 years. Most trauma mechanisms of both groups were constant, with a rising of sport injuries at 8–12 years. Conclusion: Although number of patients increases only slightly over a decade, there was a clear increase in major injuries, particularly extremity fractures, peaking at 8–12 years. At this age also sport accidents significantly increased. At least, admittance to resuscitation room rose but without an increase of multiple injured patients.

Background: Surgical complications are associated with a significant burden to patients and hospitals and are increasingly discussed in recent literature. This cohort study reviewed surgery-related complications in a Level I trauma center. The effect of a complication avoidance care bundle on the rate of surgical complications was analyzed. Methods: All complications (surgical and nonsurgical) that occur in our trauma department are prospectively captured using a standardized documentation form and are discussed and analyzed in a weekly trauma Morbidity and Mortality (M&M) conference. Surgical complication rates are calculated using the annual surgical procedure numbers. Based on discussions in the M&M conference, a complication avoidance care bundle consisting of five measures was established: (1) Improving team situational awareness; (2) reducing operating room traffic by staff members and limiting door-opening events; (3) preoperative screening for infectious foci; (4) adapted preoperative antibiotic prophylaxis in anatomic regions with a high risk of infectious complications; and (5) use of iodine-impregnated adhesive drape. Results: The number of surgical procedures steadily increased over the study years, from 3587 in 2015 to 3962 in 2019 (an increase of 10.5%). Within this 5-year study period, the overall rate of surgical complications was 0.8%. Surgical site infections were the most frequently found complications (n = 40, 24.8% of all surgical complications), followed by screw malposition (n = 20, 12.4%), postoperative dislocations of arthroplasties (n = 18, 11.2%), and suboptimal fracture reduction (n = 18, 11.2%). Following implementation of the complication avoidance care bundle, the overall rate of surgical complications significantly decreased, from 1.14% in the year 2016 to 0.56% in the study year 2019, which represents a reduction of 51% within a 3-year time period. Conclusions: A multimodal strategy targeted at reducing the surgical complication rate can be successfully established based on a transparent discussion of adverse surgical outcomes. The combination of the different preventive measures was associated with reducing the overall complication rate by half within a 3-year time period.

In Bone Tissue Engineering (BTE), autologous bone-regenerative cells are combined with a scaffold for large bone defect treatment (LBDT). Microporous, polylactic acid (PLA) scaffolds showed good healing results in small animals. However, transfer to large animal models is not easily achieved simply by upscaling the design. Increasing diffusion distances have a negative impact on cell survival and nutrition supply, leading to cell death and ultimately implant failure. Here, a novel scaffold architecture was designed to meet all requirements for an advanced bone substitute. Biofunctional, porous subunits in a load-bearing, compression-resistant frame structure characterize this approach. An open, macro- and microporous internal architecture (100 µm–2 mm pores) optimizes conditions for oxygen and nutrient supply to the implant’s inner areas by diffusion. A prototype was 3D-printed applying Fused Filament Fabrication using PLA. After incubation with Saos-2 (Sarcoma osteogenic) cells for 14 days, cell morphology, cell distribution, cell survival (fluorescence microscopy and LDH-based cytotoxicity assay), metabolic activity (MTT test), and osteogenic gene expression were determined. The adherent cells showed colonization properties, proliferation potential, and osteogenic differentiation. The innovative design, with its porous structure, is a promising matrix for cell settlement and proliferation. The modular design allows easy upscaling and offers a solution for LBDT.

In acute and chronic infections of soft tissue, a radical surgical debridement is necessary, and is regarded as the ‘Gold Standard, as well as an immediately systemic antibiotic therapy. Additional treatment with local antibiotics and/or antibiotic-containing materials is commonly used in clinical settings, but the efficient concentration of the antibiotic is not well-known.