Computed tomography-based comparison of the greater sigmoid notch restoration after tension-band wiring in osteotomized olecranon and transverse olecranon fracture.

Abstract

PurposeTo determine whether the restoration of greater sigmoid notch (GSN) congruity differs between osteotomized and simple fractured olecranon treated with tension-band wiring (TBW) using arc center distance (ACD) as a quantitative radiographic indicator.MethodsWe retrospectively evaluated 45 patients who underwent TBW with ring pins, including 23 who underwent olecranon osteotomy and 22 with Mayo type 2A olecranon fractures. Postoperative sagittal computed tomography images were analysed to measure ACD, articular gap, step-off, interfragmentary distance (IFD), and osteotomy angle. GSN was considered congruent when ACD was <2 mm. Subgroup analysis evaluated the association between osteotomy angle and GSN restoration using receiver operating characteristic (ROC) analysis.ResultsCongruent GSN was achieved less frequently in the osteotomy group than in the fracture group (60.9% vs 90.9%, <i>p</i> = 0.019). The osteotomy group showed a higher ACD (1.2 ± 1.1 mm vs 0.5 ± 0.8 mm); however, there were no differences in articular gap, step-off, IFD, and bone mineral density between the groups. In the osteotomy group, the mean osteotomy angle was significantly smaller in the incongruent subgroup than in the congruent subgroup (12.2 ± 3.6° vs 20.7 ± 4.4°). ROC analysis identified a 19.0° cutoff (area under the curve = 0.948) for predicting congruent restoration, with 100% sensitivity and 78.6% specificity.ConclusionGSN restoration after TBW was less accurate in olecranon osteotomies than in simple olecranon fractures. A more transverse osteotomy angle (<19°) was associated with incongruent restoration. Maintaining an osteotomy obliquity of approximately 20° may help preserve articular congruity.