BACKGROUND In shoulders with traumatic anterior instability, a bipolar bone defect has recently been recognized as an important indicator of the prognosis. PURPOSE To investigate the influence of bipolar bone defects on postoperative recurrence after arthroscopic Bankart repair performed at primary instability. STUDY DESIGN Cohort study; Level of evidence, 3. METHODS The study group consisted of 45 patients (45 shoulders) who underwent arthroscopic Bankart repair at primary instability before recurrence and were followed for at least 2 years. The control group consisted of 95 patients (95 shoulders) with recurrent instability who underwent Bankart repair and were followed for at least 2 years. Glenoid defects and Hill-Sachs lesions were classified into 5 size categories on 3-dimensional computed tomography and were allocated scores ranging from 0 for no defect to 4 for the largest defect. The shoulders were classified according to the total score for both lesions (0-8 points). The postoperative recurrence rate was investigated for each score of bipolar bone defects and was compared between patients with primary instability and patients with recurrent instability. The same analysis was performed for the age at operation (<20 years, 20-29 years, or ≥30 years) and for the presence of an off-track Hill-Sachs lesion. RESULTS Bipolar bone defects were smaller in shoulders with primary instability (mean ± SD defect score, 1.4 ± 1.5 points) than in those with recurrent instability (3.6 ± 1.9 points) and were larger in older patients than in younger patients at the time of primary instability. The postoperative recurrence rate was low (6.7%) in shoulders with primary instability regardless of the size of the bipolar bone defect and the patient's age, whereas the postoperative recurrence rate was high (23.2%) in shoulders with recurrent instability, especially among patients younger than 20 years with bipolar bone defects of 2 points or greater. An off-track Hill-Sachs lesion was found in only 1 patient in the oldest age group (2.2%) at primary instability, but it was found in 19 patients (20%) at recurrent instability, including 14 patients younger than 30 years. Among patients with an off-track lesion, the postoperative recurrence rate was significantly higher in patients younger than 20 years with recurrent instability (recurrence rates: <20 years, 71.4%; 20-29 years, 14.3%; ≥30 years, 0%). CONCLUSION The recurrence rate was consistently low in patients with primary instability and was significantly influenced by bipolar bone defect size and patient age in patients with recurrent instability.

中文翻译：

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关节镜Bankart修复原发性肩部不稳定性与复发性不稳定性相比，术后复发性不稳定性：双极骨缺损大小的影响。

背景技术在具有创伤性前部不稳定性的肩膀中，双极型骨缺损最近被认为是预后的重要指标。目的探讨双极骨缺损对关节镜行原发性不稳行Bankart修复后术后复发的影响。研究设计队列研究；证据等级，3。方法该研究组由45例患者（45肩）组成，他们在复发前进行了原发性不稳定的关节镜下Bankart修复，并至少随访了2年。对照组由95例（95例肩膀）复发性不稳定性患者组成，他们接受了Bankart修复，并接受了至少2年的随访。关节盂缺损和Hill-Sachs病变在3维计算机断层扫描上分为5个大小类别，并分配分数，范围从0（无缺陷）到4（最大缺陷）。根据两种病变的总分（0-8分）对肩膀进行分类。对每个双极性骨缺损评分评估了术后复发率，并比较了原发性不稳定患者和复发性不稳定患者的术后复发率。对于手术年龄（<20岁，20-29岁或≥30岁）以及是否存在偏离轨道的希尔-萨克斯病灶，进行了相同的分析。结果原发性不稳定的肩膀双极性骨缺损（平均值±SD缺损评分，1.4±1.5分）比复发性不稳定的肩膀小（3.6±1）。9分），并且在原发性不稳定时，老年患者比年轻患者更大。不管双极性骨缺损的大小和患者的年龄如何，原发性不稳定的肩膀的术后复发率均较低（6.7％），而复发性不稳定的肩膀的术后复发率较高（23.2％），尤其是在年龄较小的患者中超过20年的双极性骨缺损为2分或更高。在原发性不稳定性中，只有一名年龄最大的患者（2.2％）发现了偏离轨道的希尔-萨克斯病灶，但在复发性不稳定性中发现了19名患者（20％），其中包括14名年龄小于30岁的患者。在病灶外的患者中，年龄小于20岁的复发性不稳定患者的术后复发率显着更高（复发率：<20岁，占71.4％； 20-29岁，占14.3％；≥30岁，占0％）。结论原发性不稳定患者的复发率一直较低，并且复发性不稳定患者的双极性骨缺损大小和患者年龄显着影响其复发率。