Akagi M, Nakamura T, Matsusue Y, Ueo T, Nishijyo K, Ohnishi E
Department of Orthopaedic Surgery, Kyoto University, Kyoto City, Japan.
J Bone Joint Surg Am. 2000 Nov;82(11):1626-33. doi: 10.2106/00004623-200011000-00017.
The Bisurface knee prosthesis was designed in 1989 to improve knee flexion without affecting the durability of the prosthesis. The prosthesis has a unique ball-and-socket joint in the midposterior portion of the femoral and tibial components, which functions as a posterior stabilizing cam mechanism and causes femoral rollback. The femoral component was made of alumina ceramic. The purpose of this study was to review the clinical results of the first 223 arthroplasties performed with this prosthesis in order to assess whether this new implant had achieved its design objectives.
From December 1989 to May 1994, all patients who were scheduled for primary total knee arthroplasty were enrolled in a prospective study of the Bisurface knee. The patients were evaluated clinically according to The Hospital for Special Surgery knee-rating system and with a self-administered questionnaire, and they were evaluated radiographically according to the system of the Knee Society. Kaplan-Meier survivorship analysis was performed with revision of the knee or recommendation for revision as the end point.
One hundred and sixty-six patients treated with a total of 223 consecutive primary total knee arthroplasties were enrolled in the study, and 182 knees were followed for 3.9 to 9.0 years (mean, 5.8 years). Preoperatively, the mean Hospital for Special Surgery knee score was 44.5 points. At the time of latest follow-up, the mean knee score was 86.3 points. The mean preoperative and postoperative ranges of flexion were 119 and 124 degrees, respectively. The patients, even those with a good preoperative range of motion, rarely lost deep flexion of the knee after the procedure. A revision operation was performed in eight knees (because of infection in five, instability in two, and breakage of the peg of the patellar component in one). Two knees had recurrent medial-lateral subluxations of the femorotibial articulation, which were treated nonoperatively. No prosthesis had loosened aseptically and no alumina ceramic femoral component had broken by the time of latest follow-up. The rate of survival of the implant was 94 percent (95 percent confidence interval, 90 to 98 percent) at six years. According to the patient questionnaires, 20 percent of the knees sometimes felt loose in daily living activities, which prompted us to improve the intrinsic stability of the prosthesis by improving the congruity of the ball-and-socket joint.
Total knee arthroplasty with the Bisurface prosthesis resulted in an excellent range of motion and a high level of satisfaction with the operation; the durability of the prosthesis is promising.
双表面膝关节假体于1989年设计，旨在改善膝关节屈曲功能而不影响假体的耐用性。该假体在股骨和胫骨部件的中后部有独特的球窝关节，其作用是作为后稳定凸轮机制并导致股骨后滚。股骨部件由氧化铝陶瓷制成。本研究的目的是回顾使用该假体进行的前223例关节成形术的临床结果，以评估这种新型植入物是否实现了其设计目标。
从1989年12月至1994年5月，所有计划进行初次全膝关节置换术的患者均纳入双表面膝关节的前瞻性研究。根据特种外科医院膝关节评分系统对患者进行临床评估，并使用自行填写的问卷，同时根据膝关节协会的系统对患者进行影像学评估。以膝关节翻修或翻修建议为终点进行Kaplan-Meier生存分析。
166例接受了共223例连续初次全膝关节置换术的患者纳入研究，182个膝关节随访了3.9至9.0年（平均5.8年）。术前，特种外科医院膝关节平均评分为44.5分。在最近一次随访时，膝关节平均评分为86.3分。术前和术后平均屈曲范围分别为119度和124度。患者，即使是术前活动范围良好的患者，术后很少失去膝关节的深度屈曲。8个膝关节进行了翻修手术（5个因感染，2个因不稳定，1个因髌骨关节部件的栓子断裂）。2个膝关节出现股胫关节复发性内外侧半脱位，采用非手术治疗。到最近一次随访时，没有假体发生无菌性松动，也没有氧化铝陶瓷股骨部件断裂。植入物在6年时的生存率为94%（95%置信区间，90%至98%）。根据患者问卷，20%的膝关节在日常生活活动中有时感觉松动，这促使我们通过改善球窝关节的匹配度来提高假体的固有稳定性。
使用双表面假体进行全膝关节置换术可获得极佳的活动范围，患者对手术满意度高；假体的耐用性前景良好。
