Background: 

Stemless humeral components for anatomic total shoulder arthroplasty (aTSA) have several reported potential benefits compared with stemmed implants. However, we are aware of no Level-I, randomized controlled trials (RCTs) that have compared stemless implants with stemmed implants in patients managed with aTSA. We sought to directly compare the short-term clinical and radiographic outcomes of stemless and stemmed implants to determine if the stemless implant is noninferior to the stemmed implant.

Methods: 

We performed a prospective, multicenter, single-blinded RCT comparing stemless and short-stemmed implants in patients managed with aTSA. Range-of-motion measurements and American Shoulder and Elbow Surgeons (ASES), Single Assessment Numeric Evaluation (SANE), and Constant scores were obtained at multiple time points. Device-related complications were recorded. Radiographic evaluation for evidence of loosening, fractures, dislocation, or other component complications was performed. Statistical analysis for noninferiority was performed at 2 years of follow-up for 3 primary end points: ASES score, absence of device-related complications, and radiographic signs of loosening. All other data were compared between cohorts at all time points as secondary measures.

Results: 

Two hundred and sixty-five shoulders (including 176 shoulders in male patients and 89 shoulders in female patients) were randomized and received the allocated treatment. The mean age of the patients (and standard deviation) was 62.6 ± 9.3 years, and 99% of the shoulders had a primary diagnosis of osteoarthritis. At 2 years, the mean ASES score was 92.5 ± 14.9 for the stemless cohort and 92.2 ± 13.5 for the stemmed cohort (p value for noninferiority test, <0.0001), the proportion of shoulders without device-related complications was 92% (107 of 116) for the stemless cohort and 93% (114 of 123) for the stemmed cohort (p value for noninferiority test, 0.0063), and no shoulder in either cohort had radiographic signs of loosening. Range-of-motion measurements and ASES, SANE, and Constant scores did not differ significantly between cohorts at any time point within the 2-year follow-up.

Conclusions: 

At 2 years of follow-up, the safety and effectiveness of the stemless humeral implant were noninferior to those of the stemmed humeral implant in patients managed with aTSA for the treatment of osteoarthritis. These short-term results are promising given the potential benefits of stemless designs over traditional, stemmed humeral components.

Level of Evidence: 

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

中文翻译：

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解剖性全肩关节置换术中无茎与茎肱骨组件的前瞻性，盲法，随机对照试验：短期随访结果

背景： 

与茎干植入物相比，解剖型全肩关节置换术（aTSA）的无茎肱骨部件具有多种潜在优势。但是，我们知道，尚无任何I级随机对照试验（RCT）将无茎植入物与茎植入物进行了aTSA治疗的患者进行了比较。我们试图直接比较无茎和有茎植入物的短期临床和影像学结果，以确定无茎植入物是否劣于有茎植入物。

方法： 

我们进行了一项前瞻性，多中心，单盲RCT，比较了接受aTSA治疗的患者的无茎和短茎植入物。在多个时间点获得了运动范围测量值和美国肩肘外科医师（ASES），单次评估数字评估（SANE）和常数得分。记录与设备有关的并发症。进行影像学评估以发现松动，骨折，脱位或其他并发症。在随访的2年中对3个主要终点进行了非劣效性统计分析：ASES评分，不存在与设备相关的并发症以及影像学上的松动迹象。将所有其他数据在所有时间点之间进行比较，以作为第二指标。

结果： 

265例肩（其中男性患者176例，女性患者89例）被随机分配并接受分配治疗。患者的平均年龄（和标准差）为62.6±9.3岁，并且99％的肩部患者初步诊断为骨关节炎。在2年时，无茎队列的ASES平均得分为92.5±14.9，而有茎队列的平均ASES得分为92.2±13.5（非劣效性测试的p值，<0.0001），无器械相关并发症的肩膀比例为92％（107分116例为无茎队列，而93％（123之114）为茎队列（非劣效性检验的p值，0.0063），且两个队列中没有肩部出现放射学上的松动迹象。运动范围测量和ASES，SANE，

结论： 

经过2年的随访，在接受aTSA治疗骨关节炎的患者中，无茎肱骨植入物的安全性和有效性不亚于茎干肱骨植入物的安全性和有效性。考虑到无杆设计比传统的肱骨干部件具有潜在的优势，这些短期结果令人鼓舞。

证据级别： 

治疗I级。有关证据水平的完整说明，请参见《作者说明》。