BACKGROUND Avulsion fracture of the medial head of the gastrocnemius muscle is a very rare phenomenon. There are no reports of avulsion fractures associated with multiple ligament injuries before closure of the growth plate. The authors present a case of avulsion fracture of the insertion of the medial head of the gastrocnemius muscle associated with posterior cruciate ligament injury and an avulsion fracture of the medial collateral ligament at the femoral attachment. CASE PRESENTATION A 15-year-old Japanese boy was injured by contact with another player while playing soccer. He was immediately admitted to the authors' hospital with knee pain. Radiography and computed tomography revealed an avulsion fracture of the medial collateral ligament at the femoral attachment and an avulsion fracture of the medial head of the gastrocnemius muscle. In examination under anesthesia, the Lachman test was negative and posterior drawer test was positive. Fixation of the avulsion fractures of the medial collateral ligament and medial head of the gastrocnemius was performed 9 days after the injury. After fixation, valgus instability at full extension had disappeared. The knee was immobilized in a brace for 2 weeks postoperatively. One year postoperatively, the posterior drawer test was slightly positive; however, our patient was able to ambulate without pain and returned to sports without feeling instability in his knee. CONCLUSION A rare case of avulsion fracture of the gastrocnemius muscle combined with multiple ligament injuries before closure of the growth plate is described. A satisfactory result was obtained by fixation of the avulsed bone fragments of the gastrocnemius muscle and medial collateral ligament. The authors believe that avulsion fracture of the medial head of the gastrocnemius muscle associated with posterior cruciate ligament injury should be repaired.

中文翻译：

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闭合生长板前腓肠肌内侧头撕脱性骨折与多条韧带损伤相关：一例报告。

背景技术腓肠肌内侧头撕脱性骨折是非常罕见的现象。在闭合生长板之前，没有撕裂性骨折与多条韧带损伤相关的报道。作者介绍了腓肠肌内侧头插入撕脱性骨折与后交叉韧带损伤以及股骨附件内侧副韧带撕脱性骨折的病例。案例介绍一名15岁的日本男孩在踢足球时与另一名球员接触而受伤。他因膝盖疼痛立即被送进提交人医院。射线照相和计算机断层扫描显示股骨附件内侧副韧带撕脱性骨折和腓肠肌内侧头撕脱性骨折。在麻醉下检查，Lachman试验为阴性，后抽屉试验为阳性。损伤后9天进行内侧副韧带和腓肠肌内侧头撕脱性骨折的固定。固定后，完全延伸的外翻不稳定性消失了。术后2周将膝关节固定在支架中。术后一年，后抽屉试验呈阳性。但是，我们的患者能够轻而易举地走动，并且重新运动后膝盖不会感到不稳定。结论描述了在闭合生长板之前腓肠肌撕脱性骨折合并多条韧带损伤的罕见病例。通过固定腓肠肌和内侧副韧带撕脱的骨碎片获得了满意的结果。作者认为，应修复腓肠肌内侧头撕脱性骨折与后交叉韧带损伤相关的问题。