Beaulé P-E, Roussignol X, Schmalzried T-P, Udomkiat P, Amstutz H-C, Dujardin F-H
Joint Replacement Institute at Orthopaedic Hospital, 2400S. Flower Street, Los Angeles, CA 90007, Etats-Unis.
Rev Chir Orthop Reparatrice Appar Mot. 2003 May;89(3):242-9.
The purpose of this study was to assess the results of revision surgery for recurrent total hip prosthesis dislocation using a tripolar prosthesis composed of a conventional stem with a mobile head of an intermediary prosthesis measuring more than 40 mm and a modified cup. This technique was used in two centers in Rouen France and Los Angeles USA.
Twenty-one hips in 21 patients were operated on. The mobile heads measured 40 to 47 mm. Mean patient age was 70 years (range 29-92). The indication for the tripolar prosthesis was reserved for extremely unstable hips in patients with major risk factors for recurrent dislocation. These 21 patients had experienced 95 dislocations. The acetabular cup was custom-made for the large-diameter heads. A cemented polyethylene cup was used in 14 cases and a press-fit metal-backed around a polyethylene insert in 7. The polyethylene thickness varied from 6.5 to 16 mm for the cemented cups and 4 to 5 mm for the press-fit cups. Fourteen femoral stems were left in place as were two press-fit cups where only the inserts were changed. Mean follow-up was 5.4 years (range 3-11.8).
There has been no recurrent dislocation for 20 hips. One patient experienced a dislocation one week after surgery which required a second revision procedure to reposition the acetabular implant. Final outcome was good at 7.6 years for this hip. One patient who had not had any recurrent dislocation died 4 years after the revision surgery due to a cause unrelated to the prosthesis. Two patients were lost to follow-up at 3.7 and 6 years, both were pain free and had no radiological anomalies. Infection occurred in one patient undergoing chemotherapy for a myeloma; the head and neck had to be resected. For the 20 other patients, functional outcome, assessed with the UCLA score, showed improvement in pain (5.8 preoperatively, 9.2 at last follow-up), walking (4.8 and 8 respectively), function (4 and 6 respectively), and daily activities (3.3 and 5.2 respectively). A revision procedure was necessary for one patient during the 4(th) year because of a fracture of the polyethylene insert on a metal-back cup; the insert alone was changed. Excepting the patient with infection, there were no cases of certain or probable loosening during the follow-up.
The tripolar prosthesis with a mobile cup and a large-diameter head appears to be a reliable solution for these severely unstable hips. The procedure can often be limited to the acetabular component, reducing morbidity. The thickness of the polyethylene cup is a limitation which may affect long-term survival. Search for a highly wear-resistant couple continues.
本研究旨在评估使用三极假体进行复发性全髋关节置换脱位翻修手术的结果。该三极假体由一个传统柄部、一个直径超过40毫米的中间假体的活动头以及一个改良髋臼杯组成。此技术在法国鲁昂和美国洛杉矶的两个中心使用。
对21例患者的21个髋关节进行了手术。活动头直径为40至47毫米。患者平均年龄为70岁（范围29 - 92岁）。三极假体的适应证仅限于存在复发性脱位主要危险因素的极不稳定髋关节。这21例患者共经历了95次脱位。髋臼杯是为大直径股骨头定制的。14例使用骨水泥固定的聚乙烯杯，7例使用压配金属背衬并带有聚乙烯内衬。骨水泥固定杯的聚乙烯厚度为6.5至16毫米，压配杯的聚乙烯厚度为4至5毫米。14个股骨柄保留原位，2个压配杯仅更换了内衬。平均随访时间为5.4年（范围3 - 11.8年）。
20个髋关节未再发生脱位。1例患者术后1周发生脱位，需要进行第二次翻修手术重新定位髋臼植入物。该髋关节在7.6年时最终结果良好。1例未发生复发性脱位的患者在翻修手术后4年因与假体无关的原因死亡。2例患者在3.7年和6年时失访，二者均无疼痛且无影像学异常。1例接受骨髓瘤化疗的患者发生感染，不得不切除股骨头和颈部。对于其他20例患者，根据加州大学洛杉矶分校（UCLA）评分评估的功能结果显示，疼痛（术前5.8分，末次随访时9.2分）、行走（分别为4.8分和8分）、功能（分别为4分和6分）以及日常活动（分别为3.3分和5.2分）均有改善。1例患者在第4年因金属背衬杯上的聚乙烯内衬骨折需要进行翻修手术，仅更换了内衬。除感染患者外，随访期间未出现肯定或可能的松动病例。
带有活动杯和大直径头的三极假体似乎是这些严重不稳定髋关节的可靠解决方案。该手术通常可局限于髋臼组件，降低发病率。聚乙烯杯的厚度是一个可能影响长期生存率的限制因素。寻找高度耐磨的配对仍在继续。
