AAOS 2013：单钢板能为肱骨远端关节外骨折提供足够的稳定性吗?

引言：伴有严重干骺端粉碎并且骨骼质量欠佳的肱骨远端关节外骨折的处理极具挑战性。对这类骨折需要获得牢固的复位固定以利于术后早期进行主动功能锻炼，从而最大可能地恢复肢体功能。同样重要的还有降低并发症的发生，尽可能缩短手术时间以及减少软组织剥离等。上述目标通过使用一块锁定钢板就可能达到，而不需要使用两块钢板。我们猜想对于肱骨远端关节外的骨折，以一块锁定钢板予以固定即能达到以两块普通钢板呈90度或180度安放那样所能提供的足够大的轴向及扭转强度。

方法：将18根由合成材料制造的人工肱骨平分为三组：1、两块3.5mm普通重建钢板分别安放于肱骨内外侧相互间成180度位固定组（n=6）；2、两块3.5mm普通重建钢板分别安放于外侧及后侧相互间成90度位固定组；3、一块预弯的肱骨远端干骺端锁定钢板固定组。于人工肱骨标本远端关节面以上4cm处横型截除1cm长一段骨质，然后分别按上述方式安放钢板予以固定。测量内固定装置在矢状面上和外翻应力下的抗弯曲以及抗扭转强度。以光学跟踪方法进行3维评估。

结果：单纯一块干骺端锁定钢板固定装置在矢状面上的抗弯曲强度最大（p<0.01）。而两块普通钢板固定组，不论是相互成90度还是180度安放，其外侧弯曲强度均较单一锁定钢板固定装置要高（p=0.33及p=0.59）。而两块普通钢板成180度安放的固定装置抗扭转强度最高（p<0.01）。

讨论和结论：对于肱骨远端关节外骨折而言，单一干骺端锁定钢板固定即能提供足够的稳定性。本研究所采用的三种固定装置中，单一锁定钢板固定装置在肘关节的主要活动平面，即矢状面上的强度最高，而在次要活动平面上与传统的双钢板固定装置相当。尽管两块普通钢板成90度安放时抗扭转强度最高，但这样做带来创伤较大。单一锁定钢板可以通过微创置入的方式完成手术，因此具有降低血管神经损伤以及因手术剥离较少而影响局部骨质血供的风险。

与肱骨相关的拓展阅读：

• 2013AAOS：不同年龄段幼儿肱骨髁上移位骨折的临床特征差异
• Injury：儿童肱骨髁上移位骨折早期和延迟手术并发症无差别
• 新辅化疗+假体治疗肱骨肿瘤
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Extra-articular Distal Humerus Fractures: Is One Plate Enough?
INTRODUCTION
Metaphyseal comminution and poor bone quality can make extra-articular distal humerus fractures challenging to manage. Stable reduction and fixation of this fracture pattern is required to allow for early active motion to produce the best possible result. Decreasing morbidity, minimizing operative time and surgical dissection is also desirable. Locking plate could accomplish these goals by using one plate instead of two. Our hypothesis is that a single posterolateral locking plate used for fixation of extra-articular distal humerus fractures provides a construct with axial and torsional stiffness comparable to that of dual non-locked plates, in either a 90 degree or 180 degree configuration.
METHODS
Eighteen synthetic humeri were divided into three fixation groups (n=6): 1. Medial and lateral 3.5 mm reconstruction plates at 180°, 2. Medial and posterolateral 3.5 mm reconstruction plates oriented at 90°, 3. Single pre-contoured distal humerus metaphyseal locking plate. A 1 cm transverse osteotomy was created 4 cm from the distal articular surface and plates were applied. Stiffness in the sagittal plane, lateral bending and torsion were evaluated. 3D evaluation was done using optical tracking.
RESULTS
Single metaphyseal locking plate constructs had significantly greater sagittal plane stiffness (p<0.01). The 90° and 180[[unable to display character: ⁰]] plating constructs had greater lateral bending stiffness (p=0.33 and p=0.59). The 180° plating had the greatest torsional stiffness (p<0.01).
DISCUSSION AND CONCLUSIONS
A single metaphyseal locking plate is clinically useful for extra-articular distal humerus fractures. This study revealed that this construct is significantly stiffer in the sagittal plane, the main plane of motion of the elbow and comparable to traditional two-plate constructs in secondary planes of elbow motion. Although 90° plating was stiffest in the coronal plane and 180° plating was stiffest in torsion, they are inherently more invasive. The single locked plate allows for a less invasive construct that potentially decreases the risk of neurovascular injury and devascularizing the bone by limiting surgical dissection.