Purpose

The coordination of the glenohumeral joint and the shoulder girdle has been known as scapulohumeral rhythm. The effects of anatomical total shoulder arthroplasty (aTSA) are still subject to research. Former studies showed a higher amount of scapula lateral rotation to compensate for reduced glenohumeral elevation. The purpose of the present study was to confirm this mechanism and examine additional effects on the sternoclavicular and acromioclavicular joints’ kinematics.

Methods

3D motion analysis was used to examine 23 shoulders of 16 patients with a mean age of 71.2 (SD: 5.2) years with a mean follow up of 5.4 (SD: 2.1) years after aTSA and to compare kinematics and coordination to 22 shoulders of 11 healthy age-matched individuals with a mean age of 69.6 (SD: 5.3) years while performing elevation movement in frontal and sagittal plane.

Results

The ratio of glenohumeral to shoulder girdle contribution was reduced compared to healthy individuals: Shoulder girdle contribution to elevation was 36.5% (SD: 8.1) in the aTSA group vs. 28.5% (SD: 8.2) in the control group in the sagittal plane and 38.1% (SD: 9.1) vs. 30.2% (SD: 7.1) in the frontal plane. Kinematics of the sternoclavicular and acromioclavicular joints showed significantly different patterns.

Conclusion

Patients after aTSA showed altered shoulder girdle kinematics and higher contribution of the shoulder girdle towards elevation. Whether this is a result of the surgery, of limited glenohumeral range of motion or due to the preoperative status remains unclear. Further investigation with a prospective study design is necessary.

中文翻译：

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与年龄相匹配的健康个体相比，全肩关节置换术后患者的肩肱节律。

目的

盂肱关节和肩带的协调被称为肩肱节律。解剖型全肩关节置换术（aTSA）的效果仍需研究。以前的研究表明，肩s骨的横向旋转量较大，以补偿降低的肱骨肱骨抬高。本研究的目的是证实这种机制，并检查对肩锁和肩锁关节运动的附加影响。

方法

使用3D运动分析检查了16名患者的23个肩部，平均年龄为71.2（SD：5.2）岁，aTSA后平均随访了5.4（SD：2.1）年，并将运动学和协调性与11个患者的22个肩部进行了比较健康的年龄匹配个体，平均年龄为69.6（SD：5.3）岁，并在额叶和矢状位进行抬高运动。

结果

与健康人相比，肩肱带与肩带的贡献比例降低了：aTSA组的肩带对抬高的贡献为36.5％（SD：8.1），而对照组在矢状面和肩带的贡献为28.5％（SD：8.2）。 38.1％（SD：9.1）与额叶面的30.2％（SD：7.1）。肩锁和肩锁关节的运动学表现出明显不同的模式。

结论

aTSA后的患者表现出肩带运动学改变，肩带对抬高的贡献更大。目前尚不清楚这是外科手术的结果，盂肱运动受限还是由于术前状态所致。有必要进行前瞻性研究设计的进一步调查。