Matsuki Keisuke, Hoshika Shota, Takahashi Norimasa, Sugaya Hiroyuki, Kawashima Itaru, Banks Scott A
Sports Medicine & Joint Center, Funabashi Orthopaedic Hospital, Funabashi, Chiba, Japan.
Sports Medicine & Joint Center, Funabashi Orthopaedic Hospital, Funabashi, Chiba, Japan.
J Shoulder Elbow Surg. 2025 Sep;34(9):e740-e749. doi: 10.1016/j.jse.2024.12.016. Epub 2025 Jan 31.
Biomechanical differences between reverse shoulder arthroplasty (RSA) designs, specifically those with larger neck-shaft angles like the Grammont-type prosthesis and those with smaller neck-shaft angles such as lateralized humerus RSAs, have been analyzed in ex vivo studies. However, there are limited data on the differences in in vivo shoulder kinematics between these designs. The purpose of this study was to analyze in vivo kinematics of lateralized humerus RSA during active scaption and external rotation at the side, and to compare them to previously reported data for Grammont-type RSA.
Twenty shoulders that underwent RSA using a lateralized onlay prosthesis were included in this study. They consisted of 10 males and 5 females with a mean age of 76 years (range: 69-83). Patients underwent fluoroscopy during active scaption and external rotation at the side at or after postoperative 1 year; additionally, computed tomography was performed to create three-dimensional scapular implant models. Using these fluoroscopic images and three-dimensional models, three-dimensional shoulder kinematics were computed using model-image registration techniques. Scaption kinematics and scapular-neck distance were compared with data from previous studies on Grammont-type RSA, which were analyzed using the same techniques as in this study.
There were no significant differences in scaption kinematics between lateralized humerus and Grammont-type RSA. However, the scapular neck-insert distance during active external rotation at the side was significantly greater in lateralized humerus RSA (3.2-5 mm) than in Grammont-type RSA (approximately 1 mm, P < .001), despite the glenohumeral abduction angles being significantly smaller (P = .03).
Lateralized humerus RSA showed similar scaption kinematics to Grammont-type RSA; however, the scapular neck-insert distance during active external rotation at the side was significantly greater in lateralized humerus RSA than in Grammont-type RSA. The greater neck-insert distance may contribute to a lower incidence of scapular notching.
在体外研究中已经分析了反向肩关节置换术（RSA）设计之间的生物力学差异，特别是那些具有较大颈干角的设计，如Grammont型假体，以及那些具有较小颈干角的设计，如肱骨侧方移位的RSA。然而，关于这些设计之间体内肩关节运动学差异的数据有限。本研究的目的是分析肱骨侧方移位RSA在主动前屈上举和体侧外旋时的体内运动学，并将其与先前报道的Grammont型RSA的数据进行比较。
本研究纳入了20例使用肱骨侧方移位嵌体假体进行RSA的肩关节。其中包括10名男性和5名女性，平均年龄76岁（范围：69 - 83岁）。患者在术后1年或之后进行主动前屈上举和体侧外旋时接受荧光透视检查；此外，还进行了计算机断层扫描以创建三维肩胛植入物模型。使用这些荧光透视图像和三维模型，采用模型-图像配准技术计算三维肩关节运动学。将前屈上举运动学和肩胛-颈部距离与先前关于Grammont型RSA的研究数据进行比较，这些数据采用与本研究相同的技术进行分析。
肱骨侧方移位RSA和Grammont型RSA在前屈上举运动学方面没有显著差异。然而，尽管盂肱外展角度显著较小（P = 0.03），但在体侧主动外旋时，肱骨侧方移位RSA的肩胛颈部-植入物距离（3.2 - 5毫米）明显大于Grammont型RSA（约1毫米，P < 0.001）。
肱骨侧方移位RSA显示出与Grammont型RSA相似的前屈上举运动学；然而，在体侧主动外旋时，肱骨侧方移位RSA的肩胛颈部-植入物距离明显大于Grammont型RSA。更大的颈部-植入物距离可能有助于降低肩胛切迹的发生率。
