BACKGROUND The terrible triad injury involves an ulnohumeral dislocation, radial head fracture, and coronoid process fracture. According to traditional teaching, these injuries are strongly associated with anterolateral coronoid tip fractures and can be addressed via a lateral approach to the elbow. However, recent small clinical series suggest that some terrible triad injuries have larger coronoid fractures involving the anteromedial facet. It is important to understand how often these larger coronoid fractures occur because anteromedial facet fractures may need a different approach and different implants for fixation. An improved understanding of coronoid fracture morphology in terrible triad injuries may help surgeons construct a surgical plan. QUESTIONS/PURPOSES To better define coronoid fracture morphology in combined coronoid and radial head fractures, we therefore asked: What is the distribution of anterolateral facet versus anteromedial facet coronoid fragments in combined coronoid and radial head fractures without an ulnar shaft fracture? METHODS This retrospective, multicenter descriptive study evaluated preoperative CT scans from adult patients (18 years or older) diagnosed with combined coronoid and radial head fractures. Between February 2014 and March 2023, we identified 10,016 adult patients with elbow or forearm injuries who underwent CT scans. Among these patients, we considered those diagnosed with combined coronoid and radial head fractures without an ulnar shaft fracture based on elbow CT scans performed within 4 weeks of the injury as potentially eligible. During that time, elbow CT scans were generally ordered to assess complex fractures, confirm diagnoses when radiographs were inconclusive, evaluate joint involvement, or plan for surgical interventions. Based on that, 2% (175 of 10,016) were eligible; a further 0.001% (8 of 10,016) were excluded because of preexisting elbow pathology, prior surgery, or low-quality CT images (including slice thickness greater than 2 mm, motion artifacts, and incomplete visualization of the osseous structure of the elbow and all its articulations), leaving 2% (167 of 10,016) for analysis. The mean age was 50 ± 15 years, and more than half of the patients were female (54% [90 of 167]). Coronoid fractures in patients with combined coronoid and radial head fractures were classified using the O'Driscoll classification into three types: Type 1 (anterolateral tip fractures), Type 2 (anteromedial facet fractures), and Type 3 (base fractures). Each type was further subcategorized based on specific fracture characteristics. Two of three trained researchers independently classified the coronoid fracture type of each patient using radiographs, two-dimensional (2D) CT scans, three-dimensional (3D) CT scans, and intraoperative findings, with interrater reliability assessed by the Cohen kappa, yielding a substantial agreement value of 0.658. Disagreements were resolved through discussions with a fellowship-trained orthopaedic trauma surgeon. RESULTS Sixty-five percent (109 of 167) of patients had a Type 1 anterolateral coronoid tip fracture, 30% (50 of 167) had a Type 2 anteromedial facet fracture, and 5% (8 of 167) had a Type 3 basal fracture. CONCLUSION Surgeons should recognize that anteromedial facet involvement in coronoid fractures is more prevalent in combined coronoid and radial head fractures than previously appreciated. Future research should investigate whether these anteromedial fractures are more likely to need an additional medial approach to improve patient outcomes. CLINICAL RELEVANCE This study suggests that anteromedial facet involvement is more common than traditionally recognized in terrible triad injuries, and surgeons should be prepared to address a larger fragment when treating these injuries.

中文翻译：

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与传统教学相比，前内侧冠状突更多地参与冠状突和桡骨头的联合骨折。


背景 可怕的三联征损伤包括尺肱关节脱位、桡骨头骨折和冠状突骨折。根据传统教义，这些损伤与前外侧冠状突尖端骨折密切相关，可以通过肘部外侧入路来解决。然而，最近的小型临床系列研究表明，一些可怕的三联体损伤具有更大的冠状突骨折，累及前内侧小关节。了解这些较大的冠状突骨折发生的频率很重要，因为前内侧小关节突骨折可能需要不同的方法和不同的植入物进行固定。更好地了解可怕的三联征损伤中的冠状骨骨折形态可能有助于外科医生制定手术计划。问题/目的 为了更好地定义冠状突和桡骨头联合骨折中的冠状突骨折形态，我们因此提出了以下问题：在没有尺骨干骨折的冠状突和桡骨头合并骨折中，前外侧关节突与前内侧关节突冠状骨碎片的分布如何？方法 这项回顾性、多中心描述性研究评估了诊断为冠状突和桡骨头联合骨折的成年患者 （18 岁或以上） 的术前 CT 扫描。在 2014 年 2 月至 2023 年 3 月期间，我们确定了 10,016 名接受 CT 扫描的肘部或前臂损伤成年患者。在这些患者中，我们认为那些根据受伤后 4 周内进行的肘部 CT 扫描诊断为冠状体和桡骨头联合骨折而没有尺骨干骨折的患者可能符合条件。 在此期间，通常要求进行肘部 CT 扫描以评估复杂骨折、在 X 线照片不确定时确认诊断、评估关节受累或计划手术干预。基于此，2%（10,016 人中的 175 人）符合条件;另有 0.001%（10,016 例中的 8 例）被排除在外，因为先前存在的肘部病变、既往手术或低质量 CT 图像（包括切片厚度大于 2 毫米、运动伪影以及肘部骨结构及其所有关节的不完全可视化），留下 2%（10,016 例中的 167 例）用于分析。平均年龄为 50 ± 15 岁，超过一半的患者为女性 （54% [90/167]）。冠状突和桡骨头合并骨折患者的冠状突骨折使用 O'Driscoll 分类分为三种类型：1 型 （前外侧尖端骨折）、2 型 （前内侧小关节突骨折） 和 3 型 （基底骨折）。根据特定的断裂特征对每种类型进行进一步的亚分类。三名训练有素的研究人员中的两名使用 X 光片、二维 （2D） CT 扫描、三维 （3D） CT 扫描和术中发现独立对每位患者的冠状骨折类型进行分类，评分者间信度由 Cohen kappa 评估，得出 0.658 的实质性一致性值。通过与受过奖学金培训的骨科创伤外科医生讨论解决了分歧。结果 65% （167 例中的 109 例） 患者发生 1 型前外侧冠状突尖端骨折，30% （167 例中的 50 例） 发生 2 型前内侧关节突骨折，5% （167 例中的 8 例） 发生 3 型基底骨折。 结论 外科医生应该认识到，冠状突骨折中前内侧关节受累在冠状突和桡骨头联合骨折中比以前认识到的更普遍。未来的研究应调查这些前内侧骨折是否更可能需要额外的内侧入路来改善患者的预后。临床相关性 这项研究表明，在可怕的三联体损伤中，前内侧小关节受累比传统上认为的更常见，外科医生在治疗这些损伤时应准备好处理更大的碎片。