Tsukamoto Nobuaki, Mae Takao, Hirabayashi Kenichi, Matsushita Yu, Baba Satoshi, Komiya Norihiro, Hayashida Mitsumasa
Department of Orthopaedic Surgery, Trauma Center, Saga-ken Medical Centre Koseikan, Saga, Japan.
Trauma Case Rep. 2022 Jun 1;40:100666. doi: 10.1016/j.tcr.2022.100666. eCollection 2022 Aug.
Isolated humeral trochlea fracture, particularly in skeletally immature children, is extremely rare. The exact mechanism of this injury remains unknown because the humeral trochlea is embraced within the olecranon fossa without any muscular or ligamentous attachment. We report the treatment of a 6-year-old boy who sustained an isolated trochlea osteochondral fracture when he fell with his elbow in a flexed position while skateboarding. The patient had a history of lateral condyle fracture of the ipsilateral humerus one year previously. At the diagnosis, computed tomography (CT) revealed a small bony fragment displaced anteromedially from the superior border of the trochlea with lifting of its lateral border. Ultrasonography confirmed instability of the fractured segment. At the time of surgery, the anterior trochlea surface fracture formed a hinged fracture line on its proximal and medial border. The fracture was anatomically reduced and fixed using biodegradable pins. Postoperatively, the involved elbow showed a sufficient functional recovery to a normal level without complications during 3 years of observation, although the biodegradable pins remained radiographically in place with partial degradation. The laterally opened avulsed fragment on primary CT clearly depicted the mechanism of injury: the impact entered from the lateral side of the elbow and progressed from the longitudinal ridge of the coronoid process onto the sulcus of the trochlea to shear off the anteromedial portion of the trochlea in a medial direction. The use of biodegradable pins for fixing a trochlea fracture in a skeletally immature patient provided favorable fracture healing; however, close observation is necessary until the completion of skeletal growth because of the lack of sufficient information on the long-term prognosis of trochlea fracture, especially when treated using biodegradable implants.
孤立性肱骨滑车骨折极为罕见，尤其是在骨骼未成熟的儿童中。由于肱骨滑车被包绕在鹰嘴窝内，没有任何肌肉或韧带附着，这种损伤的确切机制尚不清楚。我们报告了一名6岁男孩的治疗情况，他在滑板时肘部屈曲摔倒，导致孤立性滑车骨软骨骨折。该患者一年前曾有同侧肱骨外侧髁骨折史。诊断时，计算机断层扫描（CT）显示一个小骨块从滑车的上缘向前内侧移位，其外侧缘抬起。超声检查证实骨折段不稳定。手术时，滑车前表面骨折在其近端和内侧缘形成一条铰链状骨折线。骨折进行了解剖复位，并用可生物降解的钢针固定。术后，在3年的观察期内，受累肘部功能恢复良好，达到正常水平，无并发症，尽管可生物降解钢针在影像学上仍留在原位且有部分降解。初次CT上外侧开放的撕脱骨块清楚地显示了损伤机制：撞击从肘部外侧进入，从冠状突的纵向嵴延伸到滑车沟，向内剪切掉滑车的前内侧部分。在骨骼未成熟的患者中使用可生物降解钢针固定滑车骨折可实现良好的骨折愈合；然而，由于关于滑车骨折长期预后的信息不足，尤其是使用可生物降解植入物治疗时，在骨骼生长完成之前需要密切观察。
