Department of Orthopaedics and Traumatology, Carémeau Teaching Hospital Center, place du Pr-Robert-Debré, 30029 Nîmes cedex 9, France.
Orthop Traumatol Surg Res. 2009 Dec;95(8):579-87. doi: 10.1016/j.otsr.2009.10.001.
Medium-term studies of ABG-1 cementless total hip arthroplasty have shown favorable functional results with excellent femoral component fixation but an abnormally high rate of periacetabular component osteolysis, which may require early revision.
The periacetabular osteolysis rate increases with time with the ABG-1 implant, leading to a high revision rate.
The objective of this study was to test this hypothesis with a minimum follow-up of 10 years and evaluate the progression of periacetabular osteolysis and its consequences on implant fixation.
A continuous series of 111 ABG-1 cementless prostheses implanted by a single operator with a theoretical minimum follow-up of 10 years. Seventy-five implants were analyzed with a mean follow-up of 13 years. All the prostheses had been implanted via a posterolateral approach and consisted of a 28 mm cup matching a head in zirconia and an antidislocation rim design high-density polyethylene insert.
Twelve cups were revised because of progressive retroacetabular osteolysis. The revisions were performed systematically although there was no pain or gross cup loosening. The revisions included resection of the granuloma, cavity filling with morselized bone grafts, and implantation of new uncemented ABG-2 cups in eight cases or cemented cups associated with a support ring in the four other cases. Thirty-two (48.5%) of the cups still in place at the end of the follow-up evaluation presented moderate and asymptomatic radiographic osteolysis, inciting close subsequent observation. No predictive factor of osteolysis onset was identified (age, body mass index, polyethylene wear, or cup orientation). None of the femoral stems was changed because of osteolysis: the only two femoral revisions resulted from periprosthetic fracture and one case of bipolar loosening. The femoral osteolysis images were small and all limited to zones 7a (18.8% of cases), 1a, and 1b (65.2% of cases). The overall survival rate of the series at 13 years of follow-up was 80.5%; the cup survival rate was 83.2%; the femoral implant, 94.3%; and failure of the femoral stem secondary to aseptic loosening was only 1.3%.
DISCUSSION, CONCLUSION: This long-term study confirms the high frequency of retroacetabular osteolysis of ABG-1 prostheses surpassing the osteolysis rate of other uncemented cups with a polyethylene insert. The absence of predictive criteria of osteolysis occurrence and the lack of symptoms warrants periodic follow-up of patients with ABG-1 cups and, if necessary, early repair of bone stock loss with grafts combined with acetabular cup revision. This procedure remains simple as long as performed before the onset of massive bone destruction, confirming the proposed revisions in this series were judicious. This study also confirms the excellent long-term fixation of the ABG-1 femoral stems derived from the osteointegration and proximal seal around the hydroxyapatite coating.
ABG-1 非骨水泥全髋关节置换术的中期研究显示，股骨部件固定效果良好，功能结果令人满意，但髋臼周围部件骨溶解发生率异常高，可能需要早期翻修。
随着时间的推移，ABG-1 植入物的髋臼周围骨溶解发生率会增加，导致翻修率高。
本研究的目的是通过至少 10 年的随访来验证这一假设，并评估髋臼周围骨溶解的进展及其对植入物固定的影响。
对一位医生连续植入的 111 例 ABG-1 非骨水泥假体进行了研究，理论上随访时间至少为 10 年。75 例植入物进行了平均 13 年的随访分析。所有假体均采用后外侧入路植入，由 28mm 髋臼杯匹配氧化锆头和防脱位缘设计的高密度聚乙烯衬垫组成。
12 个髋臼杯因进行性髋臼后缘骨溶解而被翻修。尽管没有疼痛或明显的髋臼杯松动，但仍进行了系统性翻修。翻修包括切除肉芽肿，用碎骨移植进行骨腔填充，并在 8 例中植入新的未固定 ABG-2 髋臼杯，在 4 例中植入固定髋臼杯联合支撑环。在随访评估结束时，仍有 32 个（48.5%）髋臼杯出现中度无症状放射学骨溶解，需要密切观察。未发现骨溶解发病的预测因素（年龄、体重指数、聚乙烯磨损或髋臼杯方向）。由于骨溶解而更换股骨柄的情况没有发生：只有两例股骨柄发生了假体周围骨折和一例双极松动。股骨的骨溶解图像较小，均局限于 7a 区（18.8%的病例）、1a 区和 1b 区（65.2%的病例）。13 年随访时，该系列的总体生存率为 80.5%；髋臼杯生存率为 83.2%；股骨植入物生存率为 94.3%；只有 1.3%的股骨柄因无菌性松动而失效。
讨论，结论：这项长期研究证实，ABG-1 假体的髋臼后缘骨溶解发生率高于其他带聚乙烯衬垫的非骨水泥髋臼杯，且频率较高。骨溶解发生无预测标准，且无症状，这需要对 ABG-1 髋臼杯患者进行定期随访，如果有必要，通过植骨结合髋臼杯翻修来早期修复骨质丢失。只要在发生大量骨破坏之前进行，该手术仍然简单，证实了本系列中提出的翻修是合理的。该研究还证实了 ABG-1 股骨柄的长期固定效果良好，这是由于羟基磷灰石涂层周围的骨整合和近端密封。
