- The ulnohumeral joint can tolerate substantial articular surface loss without compromising stability.
- Consider BP as an alternative to AS in unreconstructable olecranon fractures.
- Both BP and AS of olecranon fractures maintain elbow stability.
- BP has the advantage of maintaining elbow range of motion.
Olecranon fractures constitute about 10% of all forearm fractures.1 Many are low-energy fractures in osteoporotic bone in the elderly.1,2 Unstable fractures require operative fixation in which the goal is restoration of articular congruity and stability.3 Various fixation methods are used to treat unstable olecranon fractures, and outcomes are good overall.3-21 However, severely comminuted olecranon fractures, especially in osteoporotic bone, pose a unique challenge, where reconstruction may not be feasible.9 Although the articular surface can be reconstructed in most cases, reconstruction is not feasible with severe comminution or low bone mineral density. When articular congruity is no longer possible, the primary goal of fixation becomes elbow stability. Postoperative stability is linked to favorable outcomes, as it allows patients to engage in early range-of-motion (ROM) exercises, which improves joint function.5,21,22
When treating these severely comminuted olecranon fractures, surgeons have 2 options: bridge plating (BP) and acute shortening (AS). In BP, a plate is used to restore the length of the olecranon. The plate is spanned over the comminuted segment with fixation at proximal and distal pieces but without open reduction of the comminuted pieces.8 This process may be performed with or without bone grafting.21 Although any bony defect between the proximal and distal pieces may be filled, there is now a gap in articular congruity within the sigmoid notch. One concern with this fixation method is that joint stability is lost when this gap becomes too large. Surgeons therefore may decide to forgo BP and perform AS instead, as long as the coronoid is intact.21 In AS, often referred to as olecranon excision, comminuted fragments are removed and the triceps muscle advanced distally. AS constructs, often reserved for older, less active patients, yield acceptable results in this population.5 However, the long-term effects of AS in young, active patients are unclear, and biomechanical studies suggest reduced triceps muscle strength.23
Surgeons have had no studies guiding them in deciding which construct to use, BP or AS, in severely comminuted olecranon fractures in which the articular surface cannot be reconstructed.
We conducted a biomechanical study to determine the percentage loss of articular surface at which a BP construct becomes significantly clinically unstable. We also compared BP stability and AS stability for each percentage loss of articular surface and compared initial elbow ROM with the 2 methods. We hypothesized that, at a certain percentage loss of articular congruity, the BP construct would become too unstable and would require conversion to the AS construct.
Materials and Methods
Eight fresh-frozen paired cadaveric upper limbs (2 male, 2 female; mean age, 61.8 years; age range, 56-74 years) were obtained from donors with no history of elbow trauma or prior surgery. Specimens were stored at –20°C, thawed to room temperature before testing, and, using clinical and radiographic evaluation, screened for abnormalities.