Is intramedullary screw fixation biomechanically superior to locking plate fixation and/or tension band wiring in transverse olecranon fractures? A cadaveric biomechanical comparison study.

OBJECTIVES: To compare clinically important mechanical properties of three techniques used to fix transverse olecranon fractures (Arbeitsgemeinschaft fur Osteosynthesefragen and Orthopaedic Trauma Association class 2U1B1): (1) intramedullary (IM) screw, (2) locking plate, and (3) tension band wire in a realistic loading protocol using a cadaveric model. METHODS: Fresh frozen cadaveric transverse olecranon fracture models were fixed with an IM screw (n = 6), a locking plate (n = 6), or a tension band (n = 6). Compression after fixation was recorded using a pressure sensor in the fracture before samples were loaded through the triceps tendon for 500 cycles of 0-500 N, assessing implant survival. The primary outcome measure was compression force before loading. The secondary outcome was frequency of implant failure defined as breakage of the implant itself or fracture gapping >5 mm. Binary outcomes were compared with χ2, and continuous variables were compared with unadjusted analysis of variance and a multivariable regression model adjusting for age, sex, dual-energy X-ray absorptiometry T-score, and testing order. RESULTS: No statistically significant difference was shown in fracture compression between IM screw (mean, 162 N; 95% confidence interval [CI], 27-297 N), locking plate (mean, 125 N; 95% CI, -9-260 N), and tension band (mean, 163 N; 95% CI, 29-298 N) in unadjusted (p = 0.89) and adjusted (p = 0.82) analyses. A 100% implant failure rate was observed with tension band compared with 0% implant failure with IM screw or locking plate (p < 0.01). CONCLUSION: We found no statistically significant differences in compression across the fracture site among techniques. We did find a higher risk of implant failure with tension band compared with IM screw and locking plate during cyclic loading in cadaveric bone.

Fracture of the distal radius with radial artery injury: injury description and outcome of vascular repair.

INTRODUCTION: The ideal treatment of an isolated radial artery injury that is associated with a fracture of the distal radius is unknown. Our purposes were to assess the incidence of this injury pattern and to describe the outcomes of our treatment protocol. We hypothesised that combined routine repair of the artery during operative treatment results in a satisfactory outcome. METHODS: Our study group consisted of 14 patients who were treated by one surgeon with a consistent treatment algorithm. The average follow-up duration was 52 weeks. Our control group consisted of 380 patients with fracture of the distal radius without radial artery injury, who were treated by the same surgeon during a 3-year period. RESULTS: We observed a 2% incidence of isolated radial artery injury in patients treated with open reduction and internal fixation (ORIF) of the distal radius. Outcomes were comparable to those reported for operative treatment of fractures of the distal radius without radial artery injury. CONCLUSIONS: Our protocol resulted in adequate outcomes, a 71% patency rate (five of seven fractures with adequate vascular follow-up) and no evidence of symptoms related to a poorly perfused hand.

Biomechanical comparison of two headless compression screws for scaphoid fixation.

This study compared compression generation between two headless compression screws: the Synthes 3.0-mm and the Acutrak standard. Twenty scaphoids were harvested from 10 pairs of fresh cadaveric forearms. A washer-shaped load cell was inserted between the halves of each scaphoid created by a simulated fracture via osteotomy. One scaphoid of each pair was tested with the Synthes and the other with the Acutrak. Parameters of interest were peak screw torque and fracture site compression. Differences in parameters of interest were checked for significance (p < .05) with paired t tests. No significant differences were shown in mean (+/- standard deviation) peak torque (57 +/- 28 Ncm vs. 55 +/- 32 Ncm; p < .84), compression immediately after insertion (119 +/- 54 N vs. 91 +/- 37 N; p < .15), or compression 5 min after insertion (32 +/- 30 N vs. 38 +/- 24 N; p < .61) between the Synthes and Acutrak screw fixations, respectively. The choice between these two screws to stabilize scaphoid waist fractures should be based on parameters other than compression generation, such as size, availability, cost, and ease of use of the implant.