Buechel F F, Rosa R A, Pappas M J
University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark.
Clin Orthop Relat Res. 1989 Nov(248):34-49.
A congruent-contact, metal-backed, rotating-bearing patellar prosthesis has been used clinically over an 11-year period. The features of this implant include a congruent-contact, rotating bearing attached to a thin metallic anchoring plate fixed to the bone by cruciate fixturing fins. The device was initially used with methylmethacrylate and later used as a cementless, porous-coated, ingrowth fixation implant. The benefits of congruent contact with mobility to adjust its tracking position during flexion and extension help to eliminate axial shear stresses at the bone-prosthesis interface and lower the contact stresses at the bearing-metal interface to improve wear properties. Prostheses were implanted in 515 knees over a period of six months to 11 years. Of these 515 knees, 331 patellar prostheses have been followed for 24 to 132 months (mean, 73 months). Of that group of 331 implants, 141 were cemented and 190 were cementless. Specific complications involving the use of this implant were as follows. One intraoperative vertical midpatellar fracture in a cemented case went on to uneventful healing with an excellent result. Two displaced postoperative transverse midpatellar fractures (0.39%) occurred in two revision total knee arthroplasties that involved major lateral releases. One of those was a cemented revision and required removal of the implant and a partial patellectomy to gain an excellent result. In the other, a noncemented revision, the patient lacks 45 degrees of quadriceps extension and has a poor result following traumatic fracture at three years postsurgery. One patellar dislocation (0.19%) occurred in a 270-pound, osteoarthritic man in whom undersized components were used. No polyethylene wear-through, separation from the metal anchoring plate, or implant breakage was seen in this series. Overall, the performance of this congruent-contact, metal-backed, rotating-bearing patellar prosthesis indicates the prosthesis can provide long-term function and stability with few short-term or long-term complications.
一种贴合接触、金属背衬、旋转轴承的髌骨假体已在临床上使用了11年。该植入物的特点包括贴合接触、旋转轴承，其连接到一个薄金属锚固板上，该锚固板通过十字固定鳍固定在骨头上。该装置最初与甲基丙烯酸甲酯一起使用，后来用作无水泥、多孔涂层、骨长入固定植入物。贴合接触并具有在屈伸过程中调整其跟踪位置的灵活性，有助于消除骨-假体界面处的轴向剪切应力，并降低轴承-金属界面处的接触应力，从而改善磨损性能。在六个月至11年的时间里，共为515个膝关节植入了假体。在这515个膝关节中，331个髌骨假体接受了24至132个月（平均73个月）的随访。在这331个植入物中，141个采用骨水泥固定，190个为无水泥固定。使用该植入物的具体并发症如下。1例骨水泥固定病例术中发生垂直髌骨中部骨折，顺利愈合，效果良好。2例翻修全膝关节置换术中发生2例移位的术后髌骨中部横行骨折（0.39%），均涉及大范围的外侧松解。其中1例为骨水泥翻修，需要取出植入物并进行部分髌骨切除术，以获得良好效果。另一例为无水泥翻修，患者术后三年因创伤性骨折导致股四头肌伸展缺失45度，效果不佳。1例髌骨脱位（0.19%）发生在一名体重270磅的骨关节炎男性患者身上，该患者使用了尺寸过小的部件。该系列中未观察到聚乙烯磨损穿透、与金属锚固板分离或植入物断裂的情况。总体而言，这种贴合接触、金属背衬、旋转轴承的髌骨假体的性能表明，该假体能够提供长期功能和稳定性，短期或长期并发症较少。
