Considerable variation in current coronoid height and fracture measurement techniques: a systematic review.

Background: Coronoid fractures usually occur in the presence of a significant osseoligamentous injury to the elbow. Fracture size and location correlate with degree of instability and many authors have attempted to analyze the effect of fracture variation on decision making and outcome. There remains no standardized technique for measuring coronoid height or fracture size. The aim of this study was to appraise the literature regarding techniques for coronoid height measurement in order to understand variation.

Methods: Preferred Reporting Items of Systematic Reviews and Meta-Analyses guidelines were followed. A search was performed to identify studies with either a description of coronoid height, fracture size, or bone loss using the terms (Coronoid) AND (Measurement) OR (Size) OR (Height). Articles were shortlisted by screening for topic relevance based on title, abstract and, if required, full-text review. Exclusion criteria were non-English articles, those on nonhuman species or parts other than the ulna coronoid process, and studies that included patients with pre-existing elbow pathology. Shortlisted articles were grouped based on study type, imaging modality, measurement technique, and measurement parameter as well as its location along the coronoid.

Results: Thirty out of the initially identified 494 articles met the inclusion criteria. Twenty-one articles were clinical studies, 8 were cadaveric studies, and 1 combined patients as well as cadavers. A variety of imaging modalities (plain radiographs, 2-dimensional computed tomography [CT], 3-dimensional CT, magnetic resonance imaging or a combination of these) were used with CT scan (either 2-dimensional images or 3-dimensional reconstructions or both) being the most common modality used by 21 studies. Measurement technique also varied from uniplanar linear measurements in 15 studies to multiplanar area and volumetric measurements in 6 studies to techniques describing various angles and indices as an indirect measure of coronoid height in 8 studies. Across the 30 shortlisted studies, 19 different measurement techniques were identified. Fifteen studies measured normal coronoid height while the other 15 measured intact coronoid and/or fracture fragment height. The location of this measurement was also variable between studies with measurements at the apex of the coronoid in 24/30 (80%) of studies. Measurement accuracy was assessed by only 1 study. A total of 12/30 (40%) studies reported on the interobserver and intraobserver reliability of their measurement technique.

Conclusion: The systemic review demonstrated considerable variability between studies that report coronoid height or fracture size measurements. This variability makes comparison of coronoid height or fracture measurements and recommendations based on these between studies unreliable. There is need for development of a consistent, easy to use, and reproducible technique for coronoid height and bone loss.