St. Joseph's Health Centre, Department of Orthopaedic Surgery, Toronto, Ontario, Canada.
Injury. 2010 Jun;41(6):613-9. doi: 10.1016/j.injury.2009.12.012. Epub 2010 Jan 29.
Clavicle hook plates are an effective plate fixation alternative for distal clavicle fractures and severe acromioclavicular joint dislocations. However, post-operative complications associated with the subacromial portion of the hook include acromial osteolysis and subacromial impingement. We examine and quantify the three-dimensional position of the subacromial portion of the hook plate relative to surrounding acromial and subacromial structures in a series of cadaveric shoulders to determine if hook positioning predisposes the shoulder to these noted post-operative complications.
Fifteen cadaveric shoulders (seven males, eight females) were implanted with 15- or 18-mm hook plates. Dimensions of the acromion and hook plate were digitised and reconstructed into a three-dimensional model to measure acromion dimensions and distances of the subacromial hook relative to surrounding acromial and subacromial structures.
Inter-specimen dimensions of the acromion were highly variable. Mean acromion width and thickness were greater in males than in females (p=0.01). The posterior orientation of the subacromial hook varied widely (mean posterior implantation angle=32.5+/-20 degrees, range 0-67 degrees). The hook pierced the subacromial bursa in 13/15 specimens, made contact with the belly of the supraspinatus muscle in 9/15 specimens, and had focal contact at the hook tip with the undersurface of the acromion in 9/15 specimens.
The wide range of acromial dimensions leads to a high degree of variability in the positioning of the subacromial hook. The observed frequency of hook contact with surrounding subacromial structures in a static shoulder confirms that the position of the hook portion of the implant can predispose anatomic structures to the post-operative complications of subacromial impingement and bony erosion.
锁骨钩板是治疗锁骨远端骨折和严重肩锁关节脱位的有效钢板固定替代物。然而，钩的肩峰下部分相关的术后并发症包括肩峰骨溶解和肩峰下撞击。我们在一系列尸体肩上检查并量化了钩钢板肩峰下部分相对于周围肩峰和肩峰下结构的三维位置，以确定钩的位置是否使肩部容易发生这些术后并发症。
15 具尸体肩（7 名男性，8 名女性）植入了 15 或 18 毫米的钩钢板。测量了肩峰和钩板的尺寸，并将其重建为三维模型，以测量肩峰的尺寸和肩峰下钩相对于周围肩峰和肩峰下结构的距离。
肩峰的个体间尺寸差异很大。男性的肩峰宽度和厚度均大于女性（p=0.01）。肩峰下钩的后向位置差异很大（平均后向植入角度=32.5+/-20 度，范围 0-67 度）。13/15 个标本中的钩刺穿肩峰下囊，9/15 个标本中的钩与冈上肌的腹部接触，9/15 个标本中的钩尖端与肩峰下表面有局部接触。
肩峰尺寸的广泛差异导致肩峰下钩的位置存在高度的可变性。在静态肩部中观察到钩与周围肩峰下结构接触的频率证实，植入物钩部分的位置可以使解剖结构容易发生肩峰下撞击和骨侵蚀的术后并发症。
