Hospices Civils de Lyon, Centre Hospitalier Lyon-Sud, Service de chirurgie Orthopédique et Traumatologique, 69495 Pierre-Bénite cedex, France.
Orthop Traumatol Surg Res. 2013 Oct;99(6 Suppl):S285-95. doi: 10.1016/j.otsr.2013.07.009. Epub 2013 Aug 23.
Medium-term results for total ankle replacement (TAR) are in general satisfactory, but there is a high redo rate for periprosthetic osteolysis associated with the AES implant.
Comparing radioclinical findings and histologic analysis of implant revision procedure specimens can account for the elevated rate of osteolysis associated with the AES TAR implant.
In a prospective series of 84 AES TAR implants (2003-2008), 25 underwent revision for osteolysis (including three undergoing revision twice) at a mean 59.8 months. Eight patients had hydroxyapatite (HA) coated models and the others had titanium-hydroxyapatite (Ti-HA) coatings. Radiographs were systematically analyzed on Besse's protocol and evolution was monitored on AOFAS scores. The 94 specimens taken for histologic analysis during revision were re-examined, focusing specifically on foreign bodies.
Macroscopically, no metallosis or polyethylene wear was found at revision. AOFAS global and pain scores fell respectively from 89.7/100 at 1 year postoperatively to 72.9 before revision and from 32.5/40 to 20.6/40, although global scores were unchanged in 25% of patients. Radiologically, all patients showed tibial and talar osteolytic lesions, 45% showed cortical lysis and in 25% the implant had collapsed into the cysts. All specimens showed macrophagic granulomatous inflammatory reactions in contact with a foreign body; the cysts showed necrotic remodeling. Some of the foreign bodies could be identified on optical histologic examination with polyethylene in 95% of the specimens and metal in 60% (100% of HA-coated models and 33.3% of Ti-HA-coated models). Unidentifiable material was associated: a brownish pigment in Ti-HA-coated models (33.3%) and flakey bodies in 44.4% of the HA-coated models and 18.2% of the Ti-HA-coated models.
The phenomenon of periprosthetic osteolysis is still poorly understood, although implant wear debris seems to be implicated. All the patients with HA-coated implants with modular tibial stem had metal particles in the tissue around the implant, although their exact nature could not be determined. The double-layer Ti-HA coating may induce delamination by fretting while the biological bone anchorage is forming.
Prospective cohort study - Level IV.
全踝关节置换术（TAR）的中期结果通常令人满意，但与 AES 植入物相关的假体周围骨溶解的翻修率较高。
比较 AES TAR 植入物翻修手术标本的放射临床发现和组织学分析，可以解释与 AES TAR 植入物相关的骨溶解率升高的原因。
在 84 例 AES TAR 植入物（2003-2008 年）的前瞻性系列中，25 例因骨溶解而接受翻修（包括 3 例接受两次翻修），平均随访时间为 59.8 个月。8 例患者为羟基磷灰石（HA）涂层模型，其余为钛羟基磷灰石（Ti-HA）涂层。按照 Besse 方案系统分析 X 线片，并根据 AOFAS 评分监测进展。在翻修时共取出 94 份组织学分析标本，再次检查，重点关注异物。
肉眼观察，翻修时未见金属腐蚀或聚乙烯磨损。AOFAS 总评分和疼痛评分分别从术后 1 年的 89.7/100 分降至翻修前的 72.9/100 分，从 32.5/40 分降至 20.6/40 分，尽管 25%的患者总评分无变化。影像学上，所有患者均出现胫骨和距骨骨溶解病变，45%出现皮质溶解，25%的植入物已塌陷至囊肿内。所有标本均显示与异物接触的巨噬细胞肉芽肿性炎症反应；囊肿显示坏死重塑。光学组织学检查发现，95%的标本中有聚乙烯，60%的标本中有金属（100%的 HA 涂层模型和 33.3%的 Ti-HA 涂层模型）。无法识别的物质与以下物质相关：Ti-HA 涂层模型中有棕褐色色素（33.3%），HA 涂层模型中有片状物（44.4%）和 Ti-HA 涂层模型中有 18.2%。
假体周围骨溶解的现象仍未得到很好的理解，尽管植入物磨损碎片似乎与此有关。所有带有模块化胫骨柄的 HA 涂层模型的患者，其组织中有金属颗粒，但无法确定其确切性质。双层 Ti-HA 涂层可能会因微动而分层，而生物性骨固定正在形成。
前瞻性队列研究-四级。
