Motion preservation for open book injuries of the pubic symphysis -a biomechanical cadaver study.

INTRODUCTION: Open book injuries are challenging injuries that oftentimes require surgical treatment. Currently, treatment is performed with symphyseal plating requiring extensive surgery and entirely limiting physiological movement of the symphyseal joint, frequently resulting in implant failure. Therefore, we investigated the biomechanical properties of a minimally invasive tape suture construct (modified SpeedBridge™) as an alternative stabilization technique for the treatment of open book injuries in human cadaver pelvic rings. MATERIALS AND METHODS: The symphysis of 9 human cadaver pelvises was dissected and dilated to 3 cm creating an open book injury. Next, the two osteosynthesis methods (plating, modified SpeedBridge™) were applied. All specimens then underwent cyclic horizontal and vertical loading, simulating biomechanical forces while sitting, standing and walking. For statistical analysis, 3D dislocation (mm) was calculated. RESULTS: Total displacement (mm) of the pubic symphysis displayed the following means and standard deviations: native group 1.34 ± 0.62 mm, open book group 3.01 ± 1.26 mm, tape group 1.94 ± 0.59 mm and plate group 1.37 ± 0.41 mm. Comparison between native and open book (p = 0.029), open book and plate (p = 0.004), open book and tape (p = 0.031), as well as tape and plate group (p = 0.002) showed significant differences. No significant differences were found when comparing the native and tape (p = 0.059), as well as the native and plate (p = 0.999) group. CONCLUSION: While both osteosynthesis techniques sufficiently stabilized the injury, symphyseal plating displayed the highest rigidity. The modified SpeedBridge™ as a tape suture construct provided statistically sufficient biomechanical stability while maintaining symphyseal micro mobility, consequently allowing ligamental healing of the injured joint without iatrogenic arthrodesis.

It Is Always the Same-A Complication Classification following Angular Stable Plating of Proximal Humeral Fractures.

INTRODUCTION: The aim of this study was to create a novel complication classification for osteosynthesis-related complications following angular stable plating of the proximal humerus subsuming the influence of these complications on clinical outcome in relation to fracture morphology and consequent revision strategies. A total of 1047 proximal humerus fractures with overall 193 osteosynthesis-associated complications (24.5%) were included. The following complication types could be clarified: complication Type 1 is defined by mild varus (<20°) or valgus displacement of the humeral head without resulting in a screw cutout through the humeral head cortex. Type 2a is defined by varus displacement (<20°) of the humeral head associated with screw cutout through the humeral head cortex. Type 2b complication is limited to displacement of the greater tuberosity, lesser tuberosity, or both tuberosities. Complication Type 2c is defined by severe varus dislocation (>20°) of the humeral head with screw cutout at the humeral head cortex. Complication Type 3 describes a displacement of the angular stable plate in the humeral shaft region with associated shaft-sided screw cutout, while the position of the humeral head remains static. Complication Type 4 is characterized by the occurrence of AVN with or without glenoidal affection (4a/b). Clinical outcome according to the constant score was mainly affected by type 2-4, leading to a deteriorated result. Depending on the type of complication, specific revision strategies can be considered. Additionally, more complex fracture patterns fostered the incidence of complications.

Mid-term functional outcome (minimum 24 months, mean 4 years) after locking plate osteosynthesis for displaced fractures of the proximal humerus in 557 cases.

BACKGROUND: The best surgical management of displaced proximal humeral fractures remains a matter of considerable debate. This study presents mid-term functional outcome (median 4 years) after locking plate osteosynthesis for displaced proximal humeral fractures. METHODS: Between February 2002 and December 2014 1031 patients with 1047 displaced proximal humeral fractures were treated by open reduction and locking plate fixation with the same implant and received consecutive prospective follow up at least 24 months after surgical treatment. Clinical follow-up consisted of Constant Murley score (CS), Disabilities of the Arm, Shoulder and Hand score (DASH), and Short Form 36 questionnaire (SF-36). Complete follow-up could be performed in 557 (53.2%) cases, with a mean follow-up of 4.0 ± 2.7 years. RESULTS: Of 557 patients (67% women; mean age at time of osteosynthesis: 68.3 ± 15.5 years) absolute CS of all patients 4 ± 2.7 years after surgery was 68.4 ± 20.3 points. Normalized CS according to Katolik was 80.4 ± 23.8 points, and CS in percentage to the contralateral side (%CS) was 87.2 ± 27.9%. DASH score was at 23.8 ± 20.8 points. Osteosynthesis related complications (secondary displacement, screw cutout, avascular necrosis (n = 117 patients) were associated with lower functional scores (mean CS was 54.5 ± 19.0 p.; nCS 64.5 ± 22.9 p.;%CS 71.2 ± 25.0%; DASH score 31.9 ± 22.4 p.). The SF 36 was 66.5 points in the case cohort and a vitality mean of 69.4 points. Patients with a complication showed lower results (SF 36 56.7; vitality mean 64.9 points). CONCLUSIONS: Overall, patients following locking plate osteosynthesis of displaced proximal humeral fractures showed good to moderate outcomes four years after surgery. Mid-term functional outcomes correlate significantly with those at 1 year postoperatively. Furthermore, there is a significant negative correlation of midterm functional outcome with the occurrence of complications. LEVEL OF EVIDENCE: Level III, prospective nonconsecutive patients.

Biomechanical comparison of screw vs. cerclage refixation in orthogeriatric lesser trochanteric fractures: a cadaveric study.

PURPOSE: Osteoporosis-related proximal femur fractures continue to increase significantly due to demographic change. This study was designed to evaluate the biomechanical stability of two different fixation methods (cerclage vs. screw) for refixation of a trochanter minor fragment in the pertrochanteric fractures in cadaveric bones. METHODS: Artificial bones (n = 14) and human bones (n = 16) were treated with a DHS and the trochanter minor fragment was reduced by cerclage wiring or direct screw fixation. After preloading the simulated iliopsoas with 10 N, a tensile test was performed, ending with either a 70% loss of strength or avulsion of the fragment. The mean values of the avulsion force and the surface strain were recorded. RESULTS: All tensile tests showed no significant differences between refixation using a direct screw or wire cerclage, for both artificial bones and human specimens. Absolute values showed higher avulsion forces after direct screw fixation than refixation with a wire cerclage. The surface tension of specimens treated with direct screw fixation was lower than that of specimens treated with wire cerclage. An opposite effect was seen in artificial bones. Both effects were not statistically significant. CONCLUSION: Based on the equal stability after lag screw placement compared to cerclage wiring, we promote the placement of a lag screw into the lesser trochanter fragment in pertrochanteric femur fractures when using a dynamic hip screw. LEVEL OF EVIDENCE: Level III.