D'Antonio J A
Sewickley Valley Hospital, Pennsylvania.
Orthop Clin North Am. 1992 Apr;23(2):279-90.
Periprosthetic bone loss, associated with failed acetabular implants, results in disruption of hip mechanics and complicates further reconstruction. To restore normal biomechanics and idealize implant loads, restoration of the normal center of rotation of the hip is recommended. Johnston et al have shown that medial, inferior, and anterior placement of the acetabular component minimizes prosthetic loading, whereas lateralizing the socket relative to the normal center greatly increases joint reactive forces. Since 1984, I have made every effort to restore the normal hip center, within reason, when dealing with the bony deficient acetabulum. In most every socket revision performed during this period, cavitary lesions have been addressed simply with particulate bone grafting or a larger component. To justify the use of structural allografts for the management of segmental defects, I believe the defect must involve the supporting rim, comprise the ability to obtain prosthetic stability, compromise the ability to restore normal hip mechanics, and be located in a high-stress area, i.e., posterior or posterior-superior. Smaller rim defects, in particular those located superior and anterior, can be ignored if they do not lead to prosthetic instability. Some alteration in hip mechanics can be tolerated to avoid structural allografting, but I have elected not to accept a superior translation of greater than 2 cm nor a medial defect that compromises the ability to lateralize the prosthesis adequately towards the normal center. When segmental defects exist while the prosthesis is well contained and stable in host bone (particularly superior and posterior), structural allografts are not necessary. A possible need for bone graft exists when there is questionable stability of the implant, i.e., a segmental defect combined with poor quality host bone, and when a major part of the posterior or superior rim of the component remains uncovered. The age and activity level of the patient enter into this formula at this point, and when the question exists in a younger patient, bone grafting should be performed. A definite need for structural allografting exists when component stability cannot be obtained in host bone, when there is a loss of the weight-bearing portion of the acetabular, particularly posterior, superior, or both, and when a major alteration of hip mechanics has occurred where no medial support or superior translation of greater than 2 cm has occurred. Prosthetic selection can affect the long-term results of acetabular reconstruction. Smooth-threaded components and bipolars have not performed well in revision acetabular surgery.(ABSTRACT TRUNCATED AT 400 WORDS)
与髋臼假体植入失败相关的假体周围骨丢失会导致髋关节力学功能紊乱，并使进一步重建复杂化。为恢复正常生物力学并使假体负荷理想化，建议恢复髋关节的正常旋转中心。约翰斯顿等人已表明，髋臼组件的内侧、下方和前方放置可使假体负荷最小化，而相对于正常中心将髋臼杯外移则会大大增加关节反应力。自1984年以来，在处理骨质缺损的髋臼时，我一直尽力在合理范围内恢复正常的髋关节中心。在此期间进行的大多数髋臼翻修手术中，空洞性病变仅通过颗粒骨移植或使用更大的组件来处理。为证明使用结构性同种异体骨治疗节段性缺损的合理性，我认为缺损必须累及支撑边缘，影响获得假体稳定性的能力，损害恢复正常髋关节力学的能力，且位于高应力区域，即后方或后上方。较小的边缘缺损，尤其是位于上方和前方的缺损，如果不会导致假体不稳定，则可以忽略。为避免使用结构性同种异体骨，可耐受髋关节力学的一些改变，但我选择不接受大于2厘米的上移或会影响将假体充分外移至正常中心能力的内侧缺损。当假体在宿主骨中包容良好且稳定时（尤其是上方和后方），存在节段性缺损时无需使用结构性同种异体骨。当植入物稳定性存疑时，即节段性缺损合并宿主骨质量差，以及组件后缘或上缘的大部分仍未覆盖时，可能需要进行骨移植。此时患者的年龄和活动水平会纳入考虑范围，当年轻患者存在此问题时，应进行骨移植。当在宿主骨中无法获得组件稳定性、髋臼承重部分尤其是后方、上方或两者均缺失，以及在未发生内侧支撑或大于2厘米上移的情况下髋关节力学发生重大改变时，明确需要使用结构性同种异体骨。假体的选择会影响髋臼重建的长期效果。光滑螺纹组件和双极假体在髋臼翻修手术中的表现不佳。
