MoP的Head-Neck腐蝕，在過去，由於從未常規篩檢，而一直被忽略低估。近年來，透過數以百計的臨床研究，才讓此問題得以真正浮現。現在對於鈷離子溶出的機制、局部和系統性的病變、以及如何診斷與治療，已經知之甚詳，一致的共識就是避免使用金屬頭，便可將問題的真正根源「鈷」完全排除：
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金屬頭腐蝕已被證實在MoP普遍存在，因爲出現症狀，且鈷離子濃度超標，而需立即翻修的比例，遠超過之前想像。
“The diagnosis of ALTR secondary to corrosion is associated with cobalt levels of >1 ppb. Patients initially presented with new onset pain at a mean of 4.3 years.” J Arthroplasty. 2016 Jan;31(1):264-8.
“56.7% patients with metal heads had detectable cobalt levels with a mean of 2.0 μg/L. All patients with a ceramic head had nondetectable cobalt levels.”
J Arthroplasty. 2016 Oct;31(10):2215-20.
“Symptomatic MACC was present in 43 of 1352 patients (3.2%).”
J Arthroplasty. 2017 Aug;32(8):2546-2551.
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為了避免腐蝕病變，許多醫師已經棄用鈷鉻金屬頭。
“Retrieval studies have suggested a 28~42% prevalence of moderate to severe head/neck MACC”, “In fact, many surgeons have abandoned CoCr heads.” J Arthroplasty. 2016 Jul;31(7):1378-80.
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是時候考慮讓每位病人都使用陶瓷頭了。
“Ceramic heads should be used in all patients: a gold standard choice.” 16th Annual CCJR. 2019 Dec; Session II #10.
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在英國，早在2009年，陶瓷頭的使用量便已超越金屬頭（如下圖），時至今日，陶瓷頭更已經成為全世界的主流，有些國家甚至近乎全面使用（如日本、韓國、加拿大）。
除了慎選材質之外，大頭更已成為不可或缺的重要考量：
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36mm以上的大頭可以有效幫助降低脫臼發生率。
“The risk of revision due to dislocation is lower for 36mm or larger bearings.” EFORT Open Rev. 2018 May 21;3(5):225-231.
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金屬頭勿超過32mm，因爲會造成摩擦力矩、磨損體積、錐部壓力的劇增；若要用到36以上，應使用陶瓷頭。
“When paired with XLPE liners, the mean frictional torque of 36-mm and 40-mm CoCr heads was significantly greater than 28-mm and 32-mm.” J Arthroplasty. 2016 Mar;31(3):710-4.
“36/40-mm CoCr heads had higher volumetric wear than did 28/32-mm.”
Clin Orthop Relat Res. 2016 Feb;474(2):365-71.
“Fretting and corrosion of CoCr head is encouraged by elevated stress. Results showed that trunnion stress increases with increasing head size.”
J Arthroplasty. 2019 Jan;34(1):157-162.
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36/40陶瓷頭的使用在美國已經非常普遍，32/28小頭則逐漸式微。
“Cross-linked PE in combination with ceramic heads (particularly 36-mm) becoming the dominant bearing surface of choice.” J Arthroplasty. 2019 Jul;34(7S):S24-S27.
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