Maniar Rajesh N, Tushar Singhi, Singh Ashish, Gupta Himanshu, Nanivadekar Arun, Maniar Parul Rajesh
Lilavati Hospital, India.
Orthopedics. 2012 Aug 1;35(8):e1159-65. doi: 10.3928/01477447-20120725-13.
Rotating-platform knee implants have successively undergone modifications to improve postoperative flexion. The cruciate-sacrificing Low Contact Stress (LCS) implant (DePuy Orthopaedics, Inc, Warsaw, Indiana) was modified into the cruciate-substituting PFC Sigma RP (ΣRP) implant and further into the PFC Sigma RPF (ΣRPF) implant (DePuy Orthopaedics, Inc). The goal of this study was to determine whether these modifications improved postoperative flexion. Postoperative flexion at 2 years was compared against preoperative flexion with regard to the general demographics of each group.Statistical analysis showed that the pre- to postoperative flexion changes achieved by the ΣRP (14.6°) and the ΣRPF (2.9°) were better (P<.001) than that achieved by the LCS (-10.3°); however, between the ΣRP (14.6°) and the ΣRPF (2.9°), the change was statistically insignificant (P=.045). In subgroups with preoperative flexion less than 125°, postoperative flexion achieved was 100.1° with the LCS, 119.8° with the ΣRP, and 121.3° with the ΣRPF. The difference between the ΣRP and ΣRPF and the LCS was statistically significant (P<.001), but between the ΣRP and the ΣRPF was statistically insignificant (P=.621). In subgroups with preoperative flexion 125° or more, postoperative flexion was 125° with the LCS, 132° with the ΣRP, and 130° with the ΣRPF, with no significant difference between groups (P=.416). Both cruciate-substituting designs produced better postoperative flexion than the cruciate-sacrificing design. The ΣRP, despite less preoperative flexion (P=.004), achieved statistically better postoperative flexion than the LCS (P<.001). In subgroups with comparable preoperative flexion, no statistical difference in postoperative flexion was achieved by the ΣRP and the ΣRPF.
旋转平台膝关节植入物已先后进行了改进，以提高术后屈曲度。牺牲交叉韧带的低接触应力（LCS）植入物（迪普伊骨科公司，印第安纳州华沙）被改进为替代交叉韧带的PFC Sigma RP（ΣRP）植入物，并进一步改进为PFC Sigma RPF（ΣRPF）植入物（迪普伊骨科公司）。本研究的目的是确定这些改进是否改善了术后屈曲度。将每组患者的一般人口统计学资料与术后2年的屈曲度与术前屈曲度进行比较。统计分析表明，ΣRP（14.6°）和ΣRPF（2.9°）术前至术后的屈曲度变化比LCS（-10.3°）更好（P<0.001）；然而，在ΣRP（14.6°）和ΣRPF（2.9°）之间，变化无统计学意义（P=0.045）。在术前屈曲度小于125°的亚组中，LCS术后屈曲度为100.1°，ΣRP为119.8°，ΣRPF为121.3°。ΣRP和ΣRPF与LCS之间的差异有统计学意义（P<0.001），但ΣRP和ΣRPF之间无统计学意义（P=0.621）。在术前屈曲度为125°或更高的亚组中，LCS术后屈曲度为125°，ΣRP为132°，ΣRPF为130°，组间无显著差异（P=0.416）。两种替代交叉韧带的设计术后屈曲度均优于牺牲交叉韧带的设计。尽管ΣRP术前屈曲度较低（P=0.004），但其术后屈曲度在统计学上优于LCS（P<0.001）。在术前屈曲度相当的亚组中，ΣRP和ΣRPF术后屈曲度无统计学差异。
