Anna Janine Schreiner

Extremely low frequency pulsed electromagnetic fields cause antioxidative defense mechanisms in human osteoblasts via induction of •O 2 − and H 2 O 2

Recently, we identified a specific extremely low-frequency pulsed electromagnetic field (ELF-PEMF) that supports human osteoblast (hOBs) function in an ERK1/2-dependent manner, suggesting reactive oxygen species (ROS) being key regulators in this process. Thus, this study aimed at investigating how ELF-PEMF exposure can modulate hOBs function via ROS. Our results show that single exposure to ELF-PEMF induced ROS production in hOBs, without reducing intracellular glutathione. Repetitive exposure (>3) to ELF-PEMF however reduced ROS-levels, suggesting alterations in the cells antioxidative stress response. The main ROS induced by ELF-PEMF were •O2− and H2O2, therefore expression/activity of antioxidative enzymes related to these ROS were further investigated. ELF-PEMF exposure induced expression of GPX3, SOD2, CAT and GSR on mRNA, protein and enzyme activity level. Scavenging •O2− and H2O2 diminished the ELF-PEMF effect on hOBs function (AP activity and mineralization). Challenging the hOBs with low amounts of H2O2 on the other hand improved hOBs function. In summary, our data show that ELF-PEMF treatment favors differentiation of hOBs by producing non-toxic amounts of ROS, which induces antioxidative defense mechanisms in these cells. Thus, ELF-PEMF treatment might represent an interesting adjunct to conventional therapy supporting bone formation under oxidative stress conditions, e.g. during fracture healing.

Komplikationen in der Behandlung periprothetischer Frakturen bei einliegender Knietotalendoprothese – eine klinisch-radiologische Outcome-Analyse

Background The incidence of periprosthetic fractures associated with total knee arthroplasty (PpFxK) has been reported to be 0.3 – 5.5%. 40% of all cases are related to revision TKA. The most common localisation is the distal femur. Classification is performed according to Rorabeck (RB). RB I – II fractures are usually treated with locked plating and retrograde intramedullary nailing, whereas RB III fractures are an indication for revision arthroplasty using a hinged endoprosthesis. PpFxK of the patella can be classified according to Goldberg and PpFxK of the proximal tibia can be grouped as in Felix. Interprosthetic fractures can be regarded as a special type of PpFx. Due to the increasing numbers of TKA being performed, increasing numbers of adverse events in arthroplasty can be expected. Adverse events in the treatment of PpFxK occur in up to 41% of patients according to the literature and revision is needed in approximately 29% of all cases. Risk factors are age, osteoporosis, infection, malalignment, osteolysis/loosening of the implant and status post revision. Patients A clinical and radiographic follow-up was performed with 50 patients (14 men, 36 women) treated for PpFxK of the femur, tibia and patella between 2011 and 2015 at the department of arthroplasty at a level 1 trauma center in Europe. Results The follow-up of all patients was 68%, with an average of 19.1 ± 14.6 (1 – 49) months between PpFxK and clinical follow-up. 16% of the patients were allocated for further treatment or revision surgery from other hospitals. The patientsʼ median age was 78.0 ± 8.8 (55 – 94) years. Most patients were affected by several orthopaedic and internal medical comorbidities. PpFxK classified as RB II were the most common fractures (60%, n = 30). PpFxK usually occurred 5.0 ± 4.8 (0 – 20) years after index TKA (primary or revision TKA), mostly in patients with CR-retaining endoprosthesis, whereas PpFxK according to Felix occurred significantly earlier and mostly in hinged TKAs. Patients achieved on average a mean Oxford Knee Score of 31.1 ± 9.9 (14 – 46) points. The functional Knee Society Score (KSS) was 52.6 ± 24.4 (20 – 100) and the mean KSS was 58.7 ± 26.8 (0 – 99) points (n = 25). Radiographic evaluation of the RB I – II patients showed frontal and sagittal malalignment in 20.6% of all cases after reduction and plate fixation. The overall rate of surgical adverse events was 50%; 44% of all RB patients needed revision surgery. Adverse events comprised non-union, failure of osteosynthesis, infection, wound healing disorders and re-fractures in the RB II and the Felix subgroup. Conclusion PpFxK are severe injuries and are associated with a high rate of adverse events related to treatment. Patients often have a complex background and a history of revision surgery or periprosthetic joint infection. The treatment of PpFxK should therefore take place at a centre with expertise in traumatology as well as in revision arthroplasty. Preoperative infection diagnostic testing as well as adequate imaging (X-rays and CT) are essential. We furthermore advise early evaluation of revision arthroplasty, especially in elderly patients suffering from PpFxK with insufficient bone quality around the TKA and closeness between fracture and TKA. In the case of plate fixation, it is important to give attention to correct reduction – to prevent non-union, loosening of the implant and failure of the osteosynthesis – as well as to consider double plating.

Einschätzung der Auswirkungen eines Diabetes mellitus und einer Mangelernährung auf die postoperative Komplikationsrate und Lebensqualität von Patienten in einer unfallchirurgischen Schwerpunktklinik

BACKGROUND The prevalence of diabetes mellitus (DM) or malnutrition in hospitalised patients depends on the clinical domain, but is much higher than in the normal population. In trauma surgery, this increase is frequently associated with more postoperative complications and constantly rising costs. In addition, the quality of life of this target group is decreased, but there are only limited data from departments of traumatology and/or orthopaedics. Therefore, we aim to analyse the factors influencing the postoperative complication rate as well as the quality of life of orthopaedic and trauma patients. METHODS Within this prospective trial in the period of 06/2014 to 02/2017, we analysed data of 1643 patients from traumatology - geriatric and septic traumatology - as well as endoprosthetics with regard to the clinical outcome, the complication rate and the quality of life (Short Form Health Survey 36, SF-36) associated with diabetes mellitus (DM) and the nutritional status (Nutritional Risk Screening 2002, NRS). RESULTS Within our hospitalised group of trauma patients, the prevalence of diabetes mellitus was 12.4% and the risk for malnutrition (NRS ≥ 3) was 18.3%, which is much higher than in the normal population (DM 7.2%). Patients suffering from diabetes mellitus had significantly more complications than patients without diabetes mellitus. Similar results were found when comparing patients with a risk of malnutrition to the patients without. Furthermore, patients with DM evaluate their subjective quality of life lower than do patients without DM in the most domains of the SF-36, especially in the subjective-physical domains, while patients with NRS ≥ 3 assess their quality of life as being lower than do patients without a risk of malnutrition in all domains of the SF-36 (physical and mental). Additionally, we showed that reduced nutritional status has a greater influence on the decline in quality of life than did diabetes mellitus. CONCLUSION Both diabetes mellitus and malnutrition seems to influence the subjective quality of life and the complication rate of hospitalised trauma patients. A nationwide data collection and targeted interventions within the frame of interdisciplinary cooperation are necessary. In this way, the postoperative complication rate as well as associated higher treatment costs could be reduced.

Periprosthetic tibial fractures in total knee arthroplasty – an outcome analysis of a challenging and underreported surgical issue

BackgroundPeriprosthetic fractures after total knee arthroplasty (TKA) are an increasing problem and challenging to treat. The tibial side is commonly less affected than the femoral side wherefore few studies and case reports are available. The aim of this study was to analyze the outcome of periprosthetic tibial fractures and compare our data with current literature.MethodsAll periprosthetic tibial TKA fractures that were treated at our Level 1 Trauma Center between 2011 and 2015 were included and analyzed consecutively. The Felix classification was used to assess the fracture type and evaluation included the radiological and clinical outcome (Knee Society Score/KSS, Oxford Knee Score/OKS).ResultsFrom a total of 50 periprosthetic TKA fractures, 9 cases (7 female, 2 male; 2 cruciate retaining, 7 constrained TKAs) involving the tibial side were identified. The mean age in this group was 77 (65–85) years with a follow-up rate of 67% after a mean of 22 (0–36) months. The Felix classification showed type IB (n = 1), type IIB (n = 2), type IIIA (n = 4) and type IIIB (n = 2) and surgical intervention included ORIF (n = 6), revision arthroplasty (n = 1), arthrodesis (n = 1) and amputation (n = 1). The rate of adverse events and revision was 55.6% including impaired wound healing, infection and re-fracture respectively peri-implant fracture. Main revision surgery included soft tissue surgery, arthrodesis, amputation and re-osteosynthesis. The clinical outcome showed a mean OKS of 29 (19–39) points and a functional/knee KSS of 53 (40–70)/41 (17–72) points. Radiological analyses showed 4 cases of malalignment after reduction and plate fixation.ConclusionsPeriprosthetic tibial fractures predominantly affect elderly patients with a reduced bone quality and reveal a high complication rate. Careful operative planning with individual solutions respecting the individual patient condition is crucial. If ORIF with a plate is considered, restoration of the correct alignment and careful soft tissue management including minimal invasive procedures seem important factors for the postoperative outcome.

Implantation einer modularen Knietotalendoprothese mit distalem Femurersatz mit kompressiver Osteointegration als Rückzugsoption bei komplexer femoraler posttraumatischer Ausgangssituation

BACKGROUND Large bone defects and losses play a crucial role in both tumour surgery and in complex primary and revision total knee replacement. The established options of cemented or uncemented long intramedullary stems are limited by large bone defects and are at risk from relatively high exposure to aseptic loosening. There is no general valid agreement on implant fixation of the distal femur. A further option is the cementless fixation method with compressive osseointegration, based on the so-called Wolff law of bone remodelling. This method was developed in order to reduce the high loosening rates in revision arthroplasty due to intense stress shielding and is intended to be applied in patients with huge bone losses. The so-called Compress® system (or CPS) allows such a distal femur reconstruction. It has mainly been applied and evaluated in tumor endoprosthetics. There are currently few data on the application of this system in complex distal femoral posttraumatic deformity or revision arthroplasty. PATIENTS A case report of two male patients aged 59/56 years with a 1-year follow-up is presented. Both patients had a complex post-traumatic femoral deformity with bone loss, prior surgery and an ipsilateral hip replacement. Implantation was performed of a modular total knee replacement, consisting of a cemented modular tibia base plate and distal femoral replacement with cementless implant fixation by compressive osseointegration. Both patients were clinically and radiologically evaluated prospectively. RESULTS Good clinical and radiological results were demonstrated in both patients after distal femoral replacement by compressive osseointegration. There was no need for further or revision surgery. Both patients were rapidly able to resume their jobs. The survival rates for CPS were comparable to published values with conventional procedures. There are yet no long-term results or extensive data for revision arthroplasty or posttraumatic cases. CONCLUSIONS Besides distal femoral replacement with compressive osseointegration in oncological arthroplasty, the indication of complex distal femoral settings with large bone defects can be evaluated for daily clinical routine. Especially if there is ipsilateral total hip replacement, this option might be used to avoid interprosthetic stress risers.