We performed a retrospective level 4 study of case series.

In a retrospective study we analyzed the functional and radiological outcome of 30 proximal humeral fractures, treated by PHILOS-plate, a fixed-angle device. Two of them were characterized as type Neer III, 14 as type Neer IV, 5 as type Neer V and 9 as type Neer VI. There were 2 2-part, 16 3-part and 12 4-part fractures. According to the constant-score, the normalized constant-score and the UCLA-score, good to excellent results were obtained in 66.7, 76.7 and 76.7%. Twenty-six (86.7%) patients had no or mild pain. Active forward flexion and active abduction over 90° was possible in 26 (86.7%) cases. Four (13.3%) patients developed partial avascular necrosis. Screw perforation was seen in 3 (10%) cases, delayed union in 1 (3.3%) case, malunion in 1 case and a loosening of plate and screws in another one. A secondary varus displacement of 5°-35° with a mean of 7° was found in 19 (63.3%) cases. The average time to union was 75 days. Fixation with PHILOS-plate is an adequate treatment for displaced 2- to 4-part fractures. Even in dislocated or 4-part fractures or in patients over 65 years good to excellent results were seen in the majority of cases.

Purpose Intramedullary nailing and locked plating for fixation of olecranon fractures has recently gained popularity. However, these two new technologies have not been compared for their biomechanical efficacy. The aim of this study was to evaluate the biomechanical stability of two newly designed fracture fixation devices for treating olecranon fractures during dynamic continuous loading: the ION intramedullary locking nail and the LCP precontoured locking compression plate. Methods Simulated oblique olecranon fractures were created in eight pairs of fresh-frozen cadaver ulnae and stabilised using either the LCP or ION. Specimens were then subjected to continuous dynamic loading (from 25 to 200 N), with a continuous angle alteration between 0°and 90°of flexion, to perform a matched-pairs comparison. Significant differences in the distance between markers surrounding the fracture gap was determined using the Wilcoxon test after four and 300 loading cycles. Results The ION resulted in significantly less displacement in the fracture gap at 0°extension (P=0.036), 45°flexion (P=0.035) and 90°flexion (P=0.017) after 300 cycles of continuous loading. The measured displacements were small and were probably not of clinical significance. No mechanical failure or hardware migration was seen with either fixation technique.Conclusion This study shows significantly less micromotion for the ION than for the LCP in treating oblique olecranon fractures after 300 cycles of dynamic loading. Both implant types could be appropriate surgical techniques for fixation of selected olecranon fractures and osteotomies.

Numerous angular stable plates for the distal radius exist, and technically based comparisons of the polyaxial locking interfaces are lacking. The aim of this mechanical study was to investigate three different locking interfaces of angular stable volar plates by cantilever bending: VA-LCP Two-Column Distal Radius Plates 2.4 mm (Synthes® GmbH, Oberdorf, Switzerland), IXOS® P4 (Martin, Tuttlingen, Germany) and VariAX™ (Stryker®, Duisburg, Germany). We assessed the strength of 0°, 5°, 10° and 15° screw locking angles and tested the bending strength from 10° to 5° angles by cyclic loading until breakage. The final setup repeated the above assessments by inclusion of four locking screws. The single screw-plate interfaces of the VA-LCP showed the highest bending moment at an angle of 0° and 5°, the IXOS® P4 at an angle of 10° and 15° and the VariAX™ when changing the insertion angle from 10° into 5°. The strength of polyaxial locking interfaces and mechanism of failure proved to be different among the examined plates.