Triceps insertion violation from commonly applied olecranon plating system: a comparison

Surgeons generally avoid compromising tendon insertions during fracture fixation; however, it is a common practice to violate the triceps tendon insertion during olecranon plate fixation. The assumption in these procedures is that minimal triceps insertion is disrupted. The purpose of this study was to quantify the degree of triceps insertion that is violated, intentionally peeled off, by commonly utilized olecranon plating systems. The secondary objectives are to measure the surface area of the triceps insertion and olecranon using a 3-dimensional (3D) technique and compare them to 2 similar papers that were done using 2-dimensional (2D) measurements. Evaluating the amount of olecranon plates' violation to the triceps insertion was not one of the objectives of those papers. It was hypothesized that olecranon plate fixation violates a larger portion of the triceps footprint than previously thought.

Six olecranon plate designs and 12 cadaveric upper-extremity specimens were used. Olecranon plates, triceps insertion footprints, and olecranon surface areas were digitized as 3D surface models with a laser scanner (SG100; ShapeGrabber Inc., Ottawa, Canada). The violated triceps insertion footprint area, required to accommodate the plate surface on the olecranon, was calculated using 3D modeling software (MeshLab; ISTI - CNR Research Center, Pisa, Italy). Results were compared with both 2D and 3D measurements and the 2D surface area measurements of 2 previous studies.

The median triceps insertion footprint violation for 6 common olecranon plates was 46% (range, 40%-62%) using 3D analysis, and 47% (range, 41%-64%) using 2D analysis. The greatest footprint violations were observed with Synthes - Wide VA at 62% and Smith-Nephew Peri-LOC (Smith & Nephew, Andover, MA, USA) plates at 58%, while the least violation was seen with Wright Medical EPS (Wright Medical, Memphis, TN, USA) and Synthes - Extended (DePuy Synthes, Raynham, MA, USA) plates at 40%. The median triceps insertion surface area was 254 mm² (range, 193-348 mm²) and 260 mm² (range, 171-364 mm²) using 2D and 3D methods, respectively. Median olecranon surface area was 645 mm² (range, 478-775 mm²) and 573 mm² (range, 411-722 mm²) by 2D and 3D methods, respectively.

Many commonly used olecranon plating systems violate a large portion of the triceps insertion footprint which is up to 62% in this study. A better understanding of the triceps insertion footprint, olecranon anatomy, and clinical implications of triceps footprint disruption may lead to improvements in olecranon plate design and postoperative outcomes. Future studies should assess the possibility of any clinical implications of triceps insertion disruption.