華人踝關節形態學研究

Abstract

過去的手術失敗率太高的使得舊型的人工踝關節無法成為患者的首選，新的人工踝關節設計可以讓全踝關節成形術再次的獲得青睞，但到目前為止始終不及全髖關節成形術或是全膝關節成形術那般的成功。目前只有少部份文章討論到人工踝關節置換物的設計，而這些設計通常都被要求符合解剖學或是符合骨頭與韌帶結構的設計，然而只有非常少的文章討論到踝關節的形態學，至於專屬華人的踝關節形態學研究則完全沒有人發表，這樣的研究是可以被期待來設計專屬華人的人工踝關節，並改善華人的生活品質。 50隻在腳踝處沒有任何外傷及疾病的腳踝於本次的研究中被採用(平均長22.03公分)，全部試體都被固定在壓克力製的固定架上並經過電腦斷層掃描後，使用Amira重建得到踝關節的三維幾何模型，利用MATLAB自行開發的程式來分析踝關節的形態學參數並且分析距骨頂斷面與現行人工踝關節之差異。 本研究發現華人踝關節參數皆比高加索人小，但是小的比例並不相同，華人在距骨頂端的長寬比為1.21而高加索人的為1.37，華人比高加索人小13.2%，華人的距骨較近似正方形而高加索人的距骨較類似長方形，由此證明華人與高加索人在距骨上的差異，在與國外研究做比較後，華人的SRTa比高加索人的小10.4%，SRTi小34.45%，TaAL小20.57%。 在距骨頂斷面分析中，本研究發現現行的人工踝關節在標準安裝程序下，華人都無法安裝，原因是華人距骨頂斷面長度不足，造成安裝面積不足，此結果再次驗證華人與高加索人的差異，證明華人需要專屬於華人的人工踝關節。

Modern designs are now contributing to a remarkable renewed interest in total ankle arthroplasty (TAA), but TAA is still not as successful as total hip and total knee arthroplasty. Among the remaining issues there is the design of the prosthesis components, which are often claimed to be 'anatomical' or compatible with the bony and ligament structures. However, very little is reported in the literature about the morphology of the distal tibia and proximal talus. Not a single is dedicated to the ankle morphological parameters in the Chinese population, which are expected to be addressed particularly in prosthesis designs dedicated to meeting the requirements of oriental life style. The purpose of the current study was to bridge the gap. 50 ankle/foot cadaver specimens without traumas or diseases (mean foot length: 22.03cm) were used for the current study. Each specimen was fixed at the neutral position by a plastic clip for preparation of computerized tomography (CT) scan with a slice thickness of 0.625 mm. The 3D model of the bones were constructed based on the CT data by utilizing Amira. A MATLAB program was designed to obtain the morphological parameters of the distal tibia and proximal talus. This bar chart compares the results of the current study and those reported by Stagni and Hayes et al. In addition to above morphological parameters, we also calculated the ratio of length over width for tibia and talus. We found that although the lengths and widths of the tibia were smaller in the Chinese, the radius were not different between habitants of the two regions. Generally, the shape of talus in Chinese populations is close to a square, which is different from the rectangle shape of the talus in Caucasian. Compared to the Caucasian population, radius of the trochlea tali arc of the Chinese population is 10.4% smaller. Radius of the tibial mortise arc is 34.45% smaller. Trochlea tali length is 20.57% smaller.