METHODS: Between January 2018 and August 2023, we collected 60 isometric plain films from sixty outpatients and reviewed 56 anisometric plain films from twenty-eight emergency patients with dorsal dislocation of thumb MCP joint at Tianjin Hospital, then took measurements on the hand X-ray images. The sesamoid length on its longitudinal axis was defined as DP, the distance between the distal edge of sesamoid and thumb MCP joint was defined as DJ, and the ratio of DJ and DP was R. An independent-samples t-test and paired-samples t-test was utilized to analyze difference among data groups.
RESULTS: The 60 isometric images were from 30 male and 30 female outpatients with normal bone structure in their hands, and the 56 anisometric images of the 28 emergency patients included both preoperative and postoperative materials. Among the outpatients, the actual distance between the distal edge of sesamoid and thumb MCP joint space (DJ) was 2.09 mm and 1.40 mm in males and females, respectively. The authentic average length of sesamoid (DP) was 4.46 mm in males and 4.22 mm in females. The average value of R (the ratio of DJ and DP) in males and females was 0.49 and 0.34, respectively. There were gender-related statistical differences in DJ (p < 0.01) and R (p=0.01), but no statistical difference in DP (p > 0.05). For the 28 emergency patients, the mean value of R was -0.47 before joint reduction and 0.58 after joint reduction, with statistical difference between them (p < 0.01).
CONCLUSIONS: There was significant difference in the relative position between sesamoid and thumb MCP joint when joint dislocation and joint reduction. The distal edge of sesamoid beyond thumb MCP joint could be an evidence in diagnosing joint dorsal dislocation. The distal edge of sesamoid below thumb MCP joint could be an evidence of joint reduction.
方法:在2018年1月至2023年8月之间,我们从60名门诊患者中收集了60张等距平片,并在天津医院回顾了28例拇指背侧MCP关节脱位急诊患者的56张等距平片,然后测量了手部X射线图像。其纵轴上的芝麻骨长度定义为DP,种骨远端边缘和拇指MCP关节之间的距离定义为DJ,DJ和DP的比值为R。采用独立样本t检验和配对样本t检验来分析数据组之间的差异。
结果:60张等距图像来自30名男性和30名女性门诊患者,他们手中的骨骼结构正常,28例急诊患者的56张非等距图像包括术前和术后材料。在门诊病人中,在男性和女性中,芝麻骨和拇指MCP关节间隙(DJ)的远端边缘之间的实际距离为2.09mm和1.40mm,分别。籽粒(DP)的真实平均长度在男性中为4.46毫米,在女性中为4.22毫米。男性和女性的R(DJ和DP之比)的平均值分别为0.49和0.34。DJ(p<0.01)和R(p=0.01)存在性别相关的统计学差异,但DP无统计学差异(p>0.05)。对于28名急诊患者,关节复位前R的平均值为-0.47,关节复位后R的平均值为0.58,两者有统计学差异(p<0.01)。
结论:关节脱位和关节复位时,芝麻骨和拇指MCP关节的相对位置存在显着差异。超过拇指MCP关节的芝麻骨远端边缘可能是诊断关节背侧脱位的证据。拇指MCP关节下方的芝麻骨远端边缘可能是关节复位的证据。