Willmott H, Al-Wattar Z, Halewood C, Dunning M, Amis A
Department of Orthopaedics, Conquest Hospital, East Sussex Hospitals NHS Trust, United Kingdom.
Department of Orthopaedics, Conquest Hospital, East Sussex Hospitals NHS Trust, United Kingdom.
Foot Ankle Surg. 2018 Jun;24(3):259-263. doi: 10.1016/j.fas.2017.03.001. Epub 2017 Mar 18.
The first metatarsophalangeal joint may be fused in order to treat arthritis or instability. The use of shape-memory staples for fixation is well recognised, but little work has been done into the optimal configuration of staples.
The structural behaviour of first metatarsophalangeal joint (MTPJ) arthrodeses using shape-memory staples or crossed screws was studied using cadaveric porcine joints. Five fixation configurations were tested: single vertical or horizontal staple, paired staples in dorsal-medial configuration (0-90° to the sagittal plane), paired staples in oblique orthogonal configuration (45-135°); or two crossed screws. Specimens were loaded in cyclical dorsiflexion for 1000 cycles. Plantar gapping and shearing were measured. Specimens were then loaded to failure.
Cyclic testing caused more shear in the 45-135° staples than the crossed screws (1.0mm±0.5mm compared to 0.14mm±0.4mm, p<0.01). No significant difference was found in plantar gap formation. Single vertical and horizontal single staples failed at 15N and 19.
N, respectively. Paired 0-90° staples failed at 43N±9N, significantly lower than the 45-135° staples (141N±25N; p<0.001) and crossed screws (180N±67N; p<0.001). There was no significant difference between the 45-135° staples and crossed screws. Screws failed by sudden cortical fracture; staples displayed gradual pull-out and shearing. First MTPJ arthrodeses fixed with single staples are not recommended. Arthrodeses fixed with staples at 0-90° to the sagittal plane were significantly less strong than two crossed screws. However, positioning oblique staples at 45-135° significantly improved stability, creating a construct as strong as, crossed screws. None of the constructs was strong enough for immediate weight bearing.
第一跖趾关节可通过融合来治疗关节炎或关节不稳。使用形状记忆钉进行固定已得到广泛认可，但对于钉的最佳构型研究较少。
使用猪尸体关节研究了采用形状记忆钉或交叉螺钉进行第一跖趾关节（MTPJ）融合术的结构行为。测试了五种固定构型：单个垂直或水平钉、背内侧构型（与矢状面成0 - 90°）的成对钉、斜交正交构型（45 - 135°）的成对钉；或两枚交叉螺钉。标本进行1000次周期性背屈加载。测量跖侧间隙和剪切力。然后将标本加载至破坏。
循环测试中，45 - 135°钉的剪切力比交叉螺钉更大（分别为1.0mm±0.5mm和0.14mm±0.4mm，p<0.01）。跖侧间隙形成方面未发现显著差异。单个垂直和水平单钉分别在15N和19N时失效。
成对的0 - 90°钉在43N±9N时失效，显著低于45 - 135°钉（141N±25N；p<0.001）和交叉螺钉（180N±67N；p<0.001）。45 - 135°钉与交叉螺钉之间无显著差异。螺钉因皮质突然骨折而失效；钉表现为逐渐拔出和剪切。不推荐使用单个钉固定第一MTPJ融合术。与矢状面成0 - 90°的钉固定的融合术明显不如两枚交叉螺钉牢固。然而，将斜钉定位在45 - 135°可显著提高稳定性，形成与交叉螺钉一样牢固的结构。所有结构都不够坚固，无法立即负重。
