Objective To investigate the biomechanical influence of the elbow stability after resection of radial head and reconstruction using autogenous iliac bone graft (To fuse the radial head with the ulna, and partial excise the radial neck to form a false joint). Method 8 fresh human cadaveric elbows were dissected to establish the specimens with elbow joint and ligament. To test the contact stress at the lateral border of radial head and Coronoid process of ulna with Fuji pressure sensitive film in the conditions of eversion, 2Nm and 4 Nm valgus torque, 100N vertical load, and 0°、 30°、 60°、 90°、 120° respectively on the following groups : ①Normal control group; ②After excision of the radial head or release of the medial collateral ligament; ③After excision of the radial head together with release of the medial collateral ligament; ④After improved excision of radial head or medial collateral ligament reconstruction; ⑤After improved excision of radial head together with medial collateral ligament reconstruction. All dates were analyzed with SPSS 13.0 to make a comparison of valgus contact stress in each group. Result At 2 Nm valgus torque, in control group, the contact stress was 0.75±0.08MPa. While in experiment: (l)The contact stress was 1.04±0.11MPa (I=3.26, P < 0.05) afterexcision of the radial head, 0.82±0.07MPa (r=2.523, P>0.05) after improved radial head reconstruction, andl.00±0.09MPa (I=3.023, P < 0.05) after release of the medial collateral ligament, 0.84±0.07MPa (I=2.612, P > 0.05) after medial collateral ligament reconstruction while the elbow got the normal shape together with well stability. (2)The contact stress was 1.02±0.11MPa (t=3.261, P < 0.05) after release of the medial collateral ligament. And after excision of the radial head, the elbow lost stability obviously. Although after medial collateral ligament reconstruction, the stability got improved, it still has great influence on the elbow function. While after medial collateral ligament together with improved excision of radial head, the elbow got well stability, and the contact stress was 0.83±0.07MPa (r=2.862, P > 0.05) which is almost normal. (3)When the elbow flexed in different angle, the contact stress changed as force triangle cos30°、 cos60°、 cos90°、 cos 120° changed, the same as the experiment group. (4) At 4 Nm valgus torque, the curve of contact stress was same with at 2 Nm valgus torque, the contact stress raised obviously (1 raised 1.60times, 2 raised 1.48times), =3.534, P< 0.05. Conclusion Resection ofradial head and reconstruction using autogenous iliac bone graft can recover the contact feature of elbow, raise contact areas, and decrease valgus stress, increase stability of joint. It can also relieve complication after traditional excision ofradial head, especially in those combine with ligament injure around elbow and also can improve the fundamental of elbow dynamics. From the biomechanical view, resection of radial head and reconstruction using autogenous iliac bone graft is valuable.%目的 研究桡骨头粉碎骨折切除后用自体髂骨再造对肘关节稳定性的生物力学影响.方法 新鲜成人尸体上肢标本8侧,制成肘关节"骨-韧带"标本.在外翻力矩2Nm和4 Nm 时竖向载荷100N的压力作用下,分别在肘关节不同屈伸位时,用超低压型压力敏感片测量2 组试验标本(不同工况)在肘关节外翻时桡骨头及尺骨冠突外侧缘的压力和应力变化,用SPSS 10.0 软件作同体配对资料的检验.结果 ⑴在外翻力矩2 Nm肘关节完整时接触应力为0.75±0.08MPa,A 组:先行桡骨头切除后接触应力为1.04±0.11MPa(t=3.26,P＜ 0.05),行自体髂骨再造桡骨头后接触应力为0.82±0.07MPa(t=2.523,＞ 0.05),再行尺侧副韧带切断后接触应力为1.00±0.09MPa(t=3.023,P＜ 0.05),然后行尺侧副韧带重建后其接触应力为0.84±0.07MPa(t=2.612,P＞ 0.05),关节基本上能回复原状,肘关节稳定.B 组:先行尺侧副韧带切断后接触应力为1.02±0.11MPa(t=3.261,P＜0.05),行桡骨头切除后肘关节明显失稳,再将尺侧副韧带重建,关节接触特征虽有所改善,但影响仍很严重,再行自体髂骨再造桡骨头后标本回复到正常关节接触状态,其接触应力为0.83±0.07MPa(t=2.862,P＞ 0.05),肘关节稳定.⑵肘关节不同屈伸位时,桡骨头及尺骨冠突外侧缘的压力变化呈力三角形cos30°、cos60°、cos90°、cos120°的变化,与实验组的关节接触特征参数变化规律相一致.⑶在外翻力矩为4 Nm 时,关节接触应力值明显增加A组增加1.60倍,B 组增加1.48 倍,(t=3.534,P＜ 0.05),关节接触应力曲线与外翻力矩2 Nm 时的变化规律相一致.结论 自体髂骨再造桡骨头术能恢复肘关节的接触特征,增加关节接触面积,降低外翻应力,增加肘关节的稳定性,可减轻传统桡骨头切除术后的多种并发症,尤其在合并肘关节周围韧带损伤的情况下,有利于改善肘关节的动力学基础,从生物力学角度证明该手术方法是行之有效的.
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