Grosjean G, Courpied J-P, Moindreau M, Hunou N, Mathieu M, Hamadouche M
Centre de recherches orthopédiques cliniques, centre hospitalo-universitaire Cochin-Port-Royal (AP-HP), université Paris-V, 27, rue du Faubourg-St-Jacques, 75014 Paris, France.
Rev Chir Orthop Reparatrice Appar Mot. 2008 Nov;94(7):670-7. doi: 10.1016/j.rco.2008.05.004. Epub 2008 Jul 26.
The main reason for revision of Charnley type total hip arthroplasty is socket loosening related to high polyethylene wear and periacetabular osteolysis. In these situations, the monobloc cemented stem is frequently not loosened and it is not clear whether the femoral component can be retained during the revision procedure. The aim of this study was to evaluate surface and sphericity damage to the femoral head of a prospective and consecutive series of revision total hip arthroplasties during which the cemented monobloc femoral component has been systematically revised.
We performed 22 revisions of both components of Charnley type cemented total hip arthroplasties. In all cases, the 22.2 mm head of the monobloc femoral component was made of 316 L stainless steel. The international standard for such femoral heads includes an average surface roughness (Ra) of 0.05 microm, a total roughness (Rt) value of 0.5 microm and a sphericity of +/-5 microm. The mean age of the patients at the time of the index arthroplasty was 51.3 years. The average time to revision was 14.8 years (seven to 25 years). The reasons for revision included isolated socket loosening (12), extensive periacetabular osteolysis without socket loosening (two), recurrent dislocation associated with socket loosening (one), sepsis without implant loosening (one), loosening of both components (one), and isolated loosening of the femoral component (five). Hence, 15 of the 22 (68.2%) femoral components could theoretically have been retained. The surface roughness of the femoral heads was evaluated using a contact-type profilometer. For each head, the apex and two zones, either macroscopically scratched or with loss of the mirror finish, were analyzed. Moreover, the sphericity of the heads was measured using a spherometer.
The stem explanted after recurrent dislocation was analyzed separately as the femoral head had major scratches. The mean Ra and Rt of the series at the apex was 0.029 and 0.876 microm, respectively. The mean Ra and Rt of the series for the macroscopically damaged areas was 0.05 microm and 1.540 microm, respectively. The mean sphericity of the series was 7.2 microm. Hence among the 22 explanted stems, 10 femoral heads (45.4%) had Ra or Rt apex and 18 (81.8%) Ra or Rt scratched area values beyond ISO standards, respectively. Sphericity was greater than +/-5mm for 13 of the 22 femoral heads (59.1%). With the numbers available, the age at the time of the index arthroplasty, the BMI, the time and the reason for revision were not significantly associated with the degree of femoral head damage for both roughness and sphericity parameters.
Retaining the femoral component during revision of the total hip arthroplasty including a monobloc femoral component is theoretically an interesting alternative. However, femoral head surface damage occurring in vivo would have lead us to retain severely scratched heads in over 80% of the hips, and heads with abnormal roughness and sphericity values in over 90% of the hips. Bases upon our results, we recommend systematically revising the femoral component during revision THA including a monobloc stem, irrespective of the reason for revision.
Charnley型全髋关节置换术翻修的主要原因是与高聚乙烯磨损和髋臼周围骨溶解相关的髋臼杯松动。在这些情况下，一体式骨水泥柄通常未松动，并且在翻修手术期间股骨部件是否能够保留尚不清楚。本研究的目的是评估一系列前瞻性且连续的翻修全髋关节置换术中股骨头的表面和球形度损伤情况，在此系列手术中，一体式骨水泥股骨部件已被系统地翻修。
我们对Charnley型骨水泥全髋关节置换术的两个部件进行了22例翻修手术。在所有病例中，一体式股骨部件的22.2毫米股骨头由316L不锈钢制成。此类股骨头的国际标准包括平均表面粗糙度（Ra）为0.05微米、总粗糙度（Rt）值为0.5微米以及球形度为±5微米。初次置换手术时患者的平均年龄为51.3岁。平均翻修时间为14.8年（7至25年）。翻修原因包括孤立性髋臼杯松动（12例）、无髋臼杯松动的广泛性髋臼周围骨溶解（2例）、与髋臼杯松动相关的复发性脱位（1例）、无植入物松动的败血症（1例）、两个部件均松动（1例）以及股骨部件孤立性松动（5例）。因此，22例中的15例（68.2%）股骨部件理论上本可保留。使用接触式轮廓仪评估股骨头的表面粗糙度。对于每个股骨头，分析其顶点以及两个宏观上有划痕或失去镜面光泽的区域。此外，使用球径仪测量股骨头的球形度。
因复发性脱位而取出的柄单独进行分析，因为股骨头有严重划痕。该系列顶点处的平均Ra和Rt分别为0.029微米和0.876微米。宏观受损区域系列的平均Ra和Rt分别为0.05微米和1.540微米。该系列的平均球形度为7.2微米。因此，在22个取出的柄中，10个股骨头（45.4%）的顶点处Ra或Rt以及18个（81.8%）有划痕区域的Ra或Rt超出ISO标准。22个股骨头中有13个（59.1%）的球形度大于±5毫米。就现有数据而言，初次置换手术时的年龄、体重指数、翻修时间和翻修原因与粗糙度和球形度参数的股骨头损伤程度均无显著相关性。
在包括一体式股骨部件的全髋关节置换术翻修过程中保留股骨部件在理论上是一个有吸引力的选择。然而，体内发生的股骨头表面损伤会导致我们在超过80%的髋关节中保留严重划痕的股骨头，以及在超过90%的髋关节中保留粗糙度和球形度值异常的股骨头。基于我们的结果，我们建议在包括一体式柄的翻修全髋关节置换术期间系统地翻修股骨部件，无论翻修原因如何。
