[Femoral neck stress fracture in a young runner - a rare but severe injury]. / Laterale Schenkelhalsstressfraktur eines 29-jährigen Marathonläufers ­ eine seltene und risikobehaftete Überlastungsfraktur des Sportlers.

A 29-year-old athlete suffered from vague hip pain during the preparation for a marathon competition. During the competition, severe pain forced him to drop out after 29 kilometres. He underwent conventional x-rays immediately, which showed a displaced lateral fracture of the femoral neck. The fracture was immediately treated with a dynamic hip screw. A few days later, the patient was discharged. He returned to sport upon completion of treatment. Vague hip pain after exercise may be an indicator for a rare stress fracture of the femoral neck and should be taken into consideration in athletes. Delayed diagnostic investigation and treatment reduce return-to-sport rates and outcomes.

Biomechanical comparison of screw osteosyntheses and anatomical plating for coronoid shear fractures of the ulna.

INTRODUCTION: Among the few techniques described for the treatment of coronoid fractures, osteosynthesis techniques include screw osteosynthesis from anterior to posterior (AP) or from posterior to anterior (PA) and plate osteosynthesis. The aim of this study was to test the biomechanical stability of screw osteosynthesis and plate osteosynthesis using anatomical plates in coronoid process fractures. MATERIALS AND METHODS: On a total of 25 biomechanical synthetical ulnae, a coronoid shear fracture including 70% of the coronoid height was simulated. Osteosynthesis was then performed using two 2.7 mm screws from anterior, posterior and with use of three different anatomical plates of the coronoid process. For the biomechanical testing, axial load was applied to the fragment with 1000 cycles from 5 to 250 N, load to failure and load at 100 µm displacement. Displacements were measured using a point-based three-dimensional motion analysis system. RESULTS: Osteosynthesis using the PA-screw showed significant more displacement during cyclic loading compared with all other osteosyntheses (0.99 mm), whereas AP-screw showed the smallest displacement (0.10 mm) during cyclic loading. The PA-screw technique showed a significant lower load to failure compared to all other osteosynthesis with the highest load in AP-screw osteosynthesis. The load for 100 µm displacement was the smallest in PA-screw with a significant difference to the AP-screw and one plate osteosynthesis. CONCLUSION: Osteosynthesis of large coronoid shear fractures with two small-fragment screws from anterior allows stable fixation that is not inferior to anterior plate osteosynthesis and might be an alternative in specific fracture types. Posterior screw fixation was found as the weakest fixation method. LEVEL OF EVIDENCE: Basic science study.

Sonication of retrieved implants improves sensitivity in the diagnosis of periprosthetic joint infection.

BACKGROUND: Sonication is a valuable tool in the diagnosis of periprosthetic joint infections (PJI). However, conditions and definition criteria for PJI vary among studies. The aim of this study was to determine the diagnostic performance (i.e., specificity, sensitivity) of sonicate fluid culture (SFC) against periprosthetic tissue culture (PTC), when using European Bone and Joint Infection Society (EBJIS) criteria. METHODS: From March 2017 to April 2018, 257 implants were submitted for sonication. PJI was defined according to the EBJIS criteria as well as according to the International Consensus Meeting criteria of 2018 (ICM 2018). Only cases with at least one corresponding tissue sample were included. Samples were cultured using traditional microbiological plating techniques. Sensitivity and specificity were determined using two-by-two contingency tables. McNemar's test was used to compare proportions among paired samples. Subgroup analysis was performed dividing the cohort according to the site of PJI, previous antibiotic treatment, and time of manifestation. Prevalence of pathogens was determined for all patients as well as for specific subgroups. RESULTS: Among the 257 cases, 145 and 112 were defined as PJI and aseptic failure, respectively. When using the EBJIS criteria, the sensitivity of SFC and PTC was 69.0 and 62.8%, respectively (p = .04). Meanwhile, the specificity was 90.2 and 92.9%, respectively (p = .65). When adopting ICM 2018 criteria, the sensitivity of SFC and PTC was 87.5 and 84.4% (p = .63) respectively, while the specificity was 85.1 and 92.5% (p = .05), respectively. The most commonly identified pathogens were coagulase-negative staphylococci (26% overall), while 31% of PJI were culture-negative and 9% polymicrobial. CONCLUSIONS: SFC exhibited significantly greater sensitivity versus PTC when using the EBJIS criteria. Nevertheless, the diagnosis of PJI remains a difficult challenge and different diagnostic tools are necessary to optimize the outcome.

Bilateral Proximal Humerus Fracture - a Rare Combination with a High Complication Rate after Surgery. / Die beidseitige proximale Humerusfraktur ­ eine seltene Kombination mit hoher Komplikationsrate nach operativer Versorgung.

INTRODUCTION: Bilateral acute proximal humerus fractures are rare. There are no data available about these bilateral injuries. The aim of the study was to analyse bilateral proximal humerus fractures retrospectively in terms of incidence, complications and revisions. METHODS: All bilateral proximal humerus fractures were evaluated retrospectively using the institution's database, with the focus on cause of the injury, fracture severity and the clinical course compared to published information on monolateral proximal humerus fractures. Bilateral posterior dislocation fractures were excluded, because these fractures are a separate entity. RESULTS: Between 2005 and 2016, n = 17 patients were primarily treated within our hospital for an acute proximal humerus fracture on both sides (n = 12 female, n = 5 male, average age: 68 years; overall 34 proximal humerus fractures). The general trauma mechanism was a fall on both arms (82% [18% polytrauma]). There were 65% displaced 3-/4-part proximal humerus fractures. Angle-stable plate osteosynthesis was performed predominantly (64%), followed by fracture prosthesis (18%; tension wiring: 3%; non-operatively: 15%). Overall, n = 10 patients (59%) or n = 18 (53%) proximal humerus fractures developed a complication, primarily with loss of reduction or implant loosening (44%). In n = 14 (78%) of the complications further operations were necessary. Alcohol abuse was increasingly found in 29% of the cases within the bilateral patient cohort compared to patients with monolateral fractures. CONCLUSION: Bilateral proximal humerus fractures are mainly associated with comminuted displaced fractures and a higher complication rate in comparison to monolateral fractures after surgical treatment.