Efficacy of lysostaphin-coated titanium plates on implant-associated MRSA osteitis in minipigs.

PURPOSE: The growing incidence of implant-associated infections (IAIs) caused by biofilm-forming Staphylococcus aureus in combination with an increasing resistance to antibiotics requires new therapeutic strategies. Lysostaphin has been shown to eliminate this biofilm. Own studies confirm the effectiveness in a murine model. The current study characterizes the effects of lysostaphin-coated plates in an IAI minipig model. METHODS: The femur of 30 minipigs was stabilized with a five-hole plate, a bone defect was created, and in 20 cases methicillin-resistant Staphylococcus aureus was applied. Ten animals served as control group. After 14 days, local debridement, lavage, and plate exchange (seven-hole plate) were performed. Ten of the infected minipigs received an uncoated plate and 10 a lysostaphin-coated plate. On day 84, the minipigs were again lavaged, followed by euthanasia. Bacterial load was quantified by colony-forming units (CFU). Immunological response was determined by neutrophils, as well as interleukins. Fracture healing was assessed radiologically. RESULTS: CFU showed significant difference between infected minipigs with an uncoated plate and minipigs with a lysostaphin-coated plate (p = 0.0411). The infection-related excessive callus formation and calcification was significantly greater in the infected animals with an uncoated plate than in animals with a lysostaphin-coated plate (p = 0.0164/p = 0.0033). The analysis of polymorphonuclear neutrophils and interleukins did not reveal any pioneering findings. CONCLUSION: This study confirms the minipig model for examining IAI. Furthermore, coating of plates using lysostaphin could be a promising tool in the therapeutic strategies of IAI. Future studies should focus on coating technology of implants and on translation into a clinical model.

The influence of fracture severity on postoperative outcome and quality of life after locking plate fixation of proximal humeral fractures.

Objective: For proximal humeral fractures open reduction und internal fixation (ORIF) with a fixed-angle plate is considered the gold standard for surgical management. However, it can lead to poor functional outcomes and is associated with postoperative complications. Therefore, the purpose of this study was to investigate the influence of fracture severity by applying a new classification (simple versus complex) on clinical outcome and quality of life after ORIF of proximal humerus fractures. Methods: We conducted a prospective clinical study with an average follow-up period of 12 (SD 1) months after ORIF of proximal humeral fractures with a fixed-angle plate. The postoperative function and quality of life was measured using the Oxford Shoulder Score (OSS) and the Constant Score. Data was tested for statistical significance with the Mann-Whitney test and Fisher's exact test. Based on the findings of this study a simplified fracture classification system has been developed. Results: Seventy-two patients with a mean age of 65 years (SD 12) with 69% being males were included. According to the Neer classification, 35% (n=25) non-displaced ("one-part fractures"), 19% (n=14) two-part fractures, 15% (n=11) three-part fractures and 31% (n=22) four-part fractures were detected. Regarding the AO/OTA classification, 18% (n=13) were type A fractures, 43% (n=31) type B and 39% (n=28) type C fractures. From these criteria we derived our own fracture classification, including 50% (n=36) simple and 50% (n=36) severe fractures. Patients with simple fracture types achieved significantly higher total values in the Constant Score as well as the OSS (p=0.008; p=0.013). The cumulative incidence of complications in the entire patient collective was 14% (n=10) with humeral head necrosis (n=5) occurring only in the severe fracture group. Conclusions: The postoperative clinical outcome as well as the incidence of humeral head necrosis after ORIF of proximal humeral fractures with a fixed-angle plate correlates with the fracture type and severity. The newly derived fracture classification into simple and severe fractures is suitable with regard to clinical results and complication rate. However, prospective studies comparing ORIF vs. conservative treatment of proximal humeral fractures of the same severity are required. Level of Evidence: III.

Plate-associated localized osteitis in mini-pig by biofilm-forming Methicillin-resistant Staphylococcus aureus (MRSA): establishment of a novel experimental model.

PURPOSE: The increasing number of implant-associated infections during trauma and orthopedic surgery caused by biofilm-forming Staphylococcus aureus in combination with an increasing resistance of conventional antibiotics requires new therapeutic strategies. One possibility could be testing for different therapeutic strategies with differently coated plates. Therefore, a clinically realistic model is required. The pig offers the best comparability to the human situation, thus it was chosen for this model. The present study characterizes a novel model of a standardized low-grade acute osteitis with bone defect in the femur in mini-pigs, which is stabilized by a titanium locking plate to enable further studies with various coatings. METHODS: A bone defect was performed on the femur of 7 Aachen mini-pigs and infected with Methicillin-resistant S. aureus (MRSA ATCC 33592). The defect zone was stabilized with a titanium plate. After 14 days, a plate change, wound debridement and lavage were performed. Finally, after 42 days, the animals were lavaged and debrided again, followed by euthanasia. The fracture healing was evaluated radiologically and histologically. RESULTS: A local osteitis with radiologically visible lysis of the bone could be established. The unchanged high Colony-forming Units (CFU) in lavage, the significant differences in Interleukin (IL)-6 in blood compared to lavage and the lack of increase in Alkaline Phosphates (ALP) in serum over the entire observation period show the constant local infection. CONCLUSION: The study shows the successful induction of local osteitis with lysis of the bone and the lack of enzymatic activity to mineralize the bone. Therefore, this standardized mini-pig model can be used in further clinical studies, to investigate various coated implants, bone healing, biofilm formation and immune response in implant-associated osteitis.

Normal CRP and WBC values in total hip arthroplasty (THA) with signs of loosening. Do we need a joint aspiration?

PURPOSE: Overall Total hip arthroplasty (THA) is a very successful procedure. However, in case of complication dedicated management is required. Two major complications of THA failures are aseptic loosening (AL) and periprosthetic joint infection (PJI). The primary hypothesis of this study was that joint aspirations in patients with signs of loosening after THA are capable to detect PJI in suspected AL with negative serologic testing. METHODS: In this study a total of 108 symptomatic patients with radiographic signs of prosthetic loosening and hip pain in THA were included. Based on a standardized algorithm all patients underwent serological testing followed by joint aspiration preoperatively. Intraoperatively harvested samples were subjected to microbiological testing and served as the gold standard in differential diagnosis. Demographics, as well as the results of serologic and microbiological testing were collected from the medical records. RESULTS: Of the included patients 85 were finally diagnosed with an AL and 23 with PJI. Within the patients with PJI 13 (56%) patients demonstrated elevated CRP and WBC counts, as well as positive synovial cultures after joint aspiration. In ten patients (44%) diagnosed with PJI neither CRP nor WBC were abnormal. CONCLUSION: The diagnosis of PJI can be difficult in THA with radiographic signs of loosening. Clinical features including pain, fever, and local sings of infection are uncommon especially a long period after index operation. First-line screening testing relies on serological evaluation of CRP and WBC. However, normal CRP and WBC values cannot rule out a PJI. These cases can be detected by joint aspiration and synovial cultures reliably.

Aseptic Loosening after THA and TKA - Do gender, tobacco use and BMI have an impact on implant survival time?

PURPOSE: Aseptic loosening (AL) has been reported to be one of the most frequent complications in Total Knee Arthroplasty (TKA) and Total Hip Arthroplasty (THA). The aim of this study was to identify the effects of gender, current tobacco use and BMI on the incidence of AL and implant survival time in THA and TKA. METHODS: Between July 2012 and December 2016 all patients that were diagnosed with an AL of a primary THA or primary TKA and underwent revision surgery at a single institution were retrospectively reviewed for this study. For each patient gender, current tobacco use, BMI, and implant survival time were obtained from the medical records. RESULTS: 202 patients with 85 THA and 117 TKA were included in this study. There was no impact of the gender on implant survival times (p > 0.05) in THA and TKA. In the TKA group current tobacco use was associated with a significant shorter implant survival time (p < 0.05). For THA and TKA with cemented stem fixation a significant increase of AL was seen in overweight compared to normal weight patients (p < 0.05) and in obese compared to normal weight patients (p < 0.05). CONCLUSION: The results demonstrate that current tobacco use and elevated BMI are associated with increased rates of AL in TKA. Also, in THA with cemented stem fixation an elevated BMI is associated with an increased incidence of AL.

Fractures in German elite male soccer players.

BACKGROUND: Aim of this retrospective cohort study was to identify fracture epidemiology and off times after different types of fractures in German male elite soccer players from the first division Bundesliga based on information from the public media. METHODS: Exposure and fracture data over 7.5 consecutive seasons (2009/10 until the first half of 2016/17) were collected from two media-based register (transfermarkt.de® and kicker.de®). RESULTS: Overall, 357 fractures from 290 different players were recorded with an incidence of 0.19/1000 hours of exposure (95% CI: 0.14-0.24). Most fractures in German elite soccer players involved the lower extremities (35.3%), the head/face (30.3%) and the upper extremities (24.9%). The median off time after a fracture in German elite male professional soccer in 7.5 Season was 51.1 days (range 0-144). The number of fractures per 100 players per season decreased between 2009 and 2016. There was no significant difference in overall fracture incidence when comparing players at different position (P=0.11). Goalkeepers have a significantly (P<0.02) higher likelihood of suffering hand and finger fractures and they are significantly (P<0.03) less prone of suffering foot fractures, cranial and maxillofacial fractures (P<0.04). compared to outfield players. CONCLUSIONS: This study can confirm that male professional soccer teams experience 1-2 fractures per season in German elite soccer. The incidence of fractures in elite German soccer players decreased between 2009 and 2016. The most fractures occur in the lower extremities and there is no difference in overall fracture risk for players at different playing positions. The information from our study might be of a great importance to medical practitioners, soccer coaches and soccer manager.

Is computerised 3D templating more accurate than 2D templating to predict size of components in primary total hip arthroplasty?

INTRODUCTION: The aim of this study was to compare the accuracy of preoperative templating in total hip arthroplasty (THA) using conventional 2-dimensional (2D) and computed tomography (CT)-based 3-dimensional (3D) measures. METHODS: One hundred and sixteen consecutive primary THAs were analysed. The preoperative diagnosis was primary osteoarthritis in all cases. The 2D templating and the 3D templating were performed by two different residents. All templating results were available for the orthopaedic surgeon performing the procedure. Accuracies with regard to the predicted and actual implant sizes were determined for each procedure. Implantation of the size as planned was defined as "exact", whereas the use of components within one size larger or smaller (±1) as planned were defined as "accurate." RESULTS: The 3D templating was significantly more accurate in predicting implant sizing compared to 2D templating for primary total hip arthroplasty (THA). The difference was statistically significant for the cup templating (''exact'' p = 0.02; ''accurate'' p = 0.01) and for the stem templating (''exact'' p = 0.04; ''accurate'' p = 0.01). CONCLUSION: Our results support the superiority of 3D templating over 2D templating in predicting implant size.

Anterior cruciate ligament ruptures in German elite soccer players: Epidemiology, mechanisms, and return to play.

BACKGROUND: Anterior cruciate ligament ruptures (ACLRs) are severe sports-related injuries with significant consequences for affected players and teams. This study aims to identify the epidemiology and injury-related lay-off after ACLR in professional male soccer players from the first-division German Bundesliga. METHODS: Exposure times and incidence of anterior cruciate ligament ruptures were collected during 7.5 consecutive seasons using two media-based registers. RESULTS: A total of 72 total ACLRs were registered in 66 different players with an incidence of 0.040 per 1000h of exposure (95% CI 0.009-0.12). On average there were 9.6 ACLRs per season and 0.53 per team and season. The mean age of players affected was 24 (standard deviation±3.6) years. The number of ACLRs recorded per season fluctuated during the period observed. Goalkeepers are significantly (P<0.05) less prone to suffer an ACLR compared to outfield players. CONCLUSIONS: Understanding ACLR loading mechanisms, knowing risk factors for the injury and mean off time after ACLR are essential information for the coach, the medical staff, the elite soccer players, the insurance and team managers. Our results are in accordance with reports based on information from medical team staff. Therefore, our analysis of ACLR based on media sources may serve as an alternative for injury reports in elite soccer. The information of this study may be helpful for the medical staff taking care of professional soccer players and for orthopedic surgeons performing ACL reconstructions in this patient population.