股骨近端截骨術之電腦輔助術前規劃

Computer-Assisted Preoperative Planning for Proximal Femoral Osteotomy

侯順興(Shun-Hsin Hou)

指導教授 ： 陳文斌

中原大學/工學院/醫學工程研究所/碩士(2001年)

https://doi.org/10.6840/cycu200100364

摘要

對於年輕而較具活動性的股骨頭缺血性壞死之病患而言，股骨近端截骨術是髖關節置換術之外的另一可選擇之外科手術，理論上經由此手術可將股骨頭壞死區域轉移到非重量承載區，以減輕壞死區上應力，進而可預防股骨頭的塌陷。此研究的目的是建立3維的術前規劃，並且評估股骨近端截骨術後股骨頭上的力學變化情形。研究中的程序可提供一個較快速且有效的術前規劃，並且期望更改善股骨近端截骨術的結果。

本研究針對一個五十三歲之病人進行電腦斷層掃描並加以處理後可產生三維實體模型及有限元素模型。術前規劃程序的執行，評估前轉和後轉截骨術的術前及術後情形，壞死區落於重量承載區內的百分比例。再者，可產生模擬正常、病患的股骨近端截骨術術前及術後情形的有限元素模型。

對此特定病人經由術前規劃的結果，在幾何觀點上而言，前轉90度的手術是一個較佳的選擇，經執行後，落於重量承載區內的壞死區面積比例從74.49％減少到6.49％。在有限元素分析結果，術前模型的分析，壞死區及海綿質骨的平均蒙麥斯應力值皆超過所能承受的強度，這樣的結果顯示股骨球頭長期下來可能發生塌陷。模擬手術後轉110度的模型分析結果，處於重量承載區內壞死區的平均應力值仍是超過降伏強度。而手術前轉90度的結果，壞死區的平均應力量值則低於降伏強度。研究中病患依據術前規劃及有限元素分析結果，其建議90度的前轉可明顯的降低壞死區的應力值，並且可預防股骨球頭的塌陷。壞死區的範圍及位置都會影響股骨近端截骨術所需的方向及角度大小，經由本研究的術前規劃程序，將可根據病患個別的情況快速的提供較佳的術前建議。

關鍵字

股骨近端截骨術 ； 股骨頭缺血性壞死 ； 電腦輔助手術 ； 有限元素分析 ； 術前規劃

並列摘要

Proximal femoral osteotomy (PFO) is an alternative surgical procedure besides total hip replacement for younger and more active patients of femoral head avascular necrosis. The rationale of the procedure is to reposition the necrotic area of the femoral head to a non-weight-bearing locale, and to reduce the stresses on the necrotic zone. Then it can prevent progressive collapse of the femoral head. The purpose of this study is to develop a three-dimensional pre-surgical planner and to evaluate the biomechanical changes of the femoral head following PFO. This procedure can provide a quicker and better preoperative planning and hopefully to improve the outcome for the PFO.

Computed tomography (CT) data of a 53 year patient was processed to create a 3-D solid model and a finite element model. The preoperative planning procedure was performed by evaluating the percent ratio for the necrotic area overlapping with the weight-bearing region divided by the weight-bearing area before and after anterior and posterior rotational osteotomy. The finite element models simulating normal, pre- and post-PFO were created.

From the preoperative planning results for this specific patient, anterior rotation of 90°suggests a better choice than other cases from the geometric consideration. The percent ratio of the necrotic area overlapping with the weight-bearing area can be reduced from 74.49% to 6.49% when a 90°anterior rotation was performed. From the finite element analysis results, for the preoperative model, the average von Mises stresses of the necrotic area and the cancellous bone are greater than their yield strength. This result indicates that the collapse of femoral head may prevail. For the results of the posterior 110°rotation model, the average stress of necrotic area under weight-bearing still exceeded the yield strength. For the 90°anterior rotation model, the average stress of necrotic area was less than yield strength. Based on the preoperative planning and the finite element analysis results for this particular patient, it suggests that a 90°anterior rotation can significantly reduce the stresses on the necrotic region and can prevent progressive collapse of the femoral head. We concluded that not only the size but also the location of the necrosis would affect the choice of the direction and the angle of PFO. By using the preoperative planning procedure, a better and quicker suggestion can be provided preoperatively depending on the individual patient’s situation.

並列關鍵字

Femoral head avascular necrosis ； Computer-assisted surgery ； Preoperative planning procedure ； Finite element analysis ； roximal femoral osteotomy

參考文獻

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