Posterior Condylar Offset Does Not Correlate With Knee Flexion After TKA

作者：Ishii Yoshinori^*; Noguchi Hideo; Takeda Mitsuhiro; Sato Junko; Toyabe Shin ichi

来源：Clinical Orthopaedics and Related Research, 2013, 471(9): 2995-3001.

DOI：10.1007/s11999-013-2999-2

Studies of medial and lateral femoral posterior condylar offset have disagreed on whether posterior condylar offset affects maximum knee flexion angle after TKA. %26lt;br%26gt;We asked whether posterior condylar offset was correlated with knee flexion angle 1 year after surgery in (1) a PCL-retaining meniscal-bearing TKA implant, or in (2) a PCL-substituting mobile-bearing TKA implant. %26lt;br%26gt;Knee flexion angle was examined preoperatively and 12 months postoperatively in 170 patients who underwent primary TKAs to clarify the effect of PCL-retaining (85 knees) and PCL-substituting (85 knees) prostheses on knee flexion angle. A quasirandomized design was used; patients were assigned to receive one or the other implant using chart numbers. A quantitative three-dimensional technique with CT was used to examine individual changes in medial and lateral posterior condylar offsets. %26lt;br%26gt;In PCL-retaining meniscal-bearing knees, there were no significant correlations between posterior condylar offset and knee flexion at 1 year. In these knees, the mean (+/- SD) postoperative differences in medial and lateral posterior condylar offsets were 0.0 +/- 3.6 mm and 3.8 +/- 3.6 mm, respectively. The postoperative change in maximum knee flexion angle was -5A degrees +/- 15A degrees. In PCL-substituting rotating-platform knees, similarly, there were no significant correlations between posterior condylar offset and knee flexion 1 year after surgery. In these knees, the mean postoperative differences in medial and lateral posterior condylar offsets were -0.5 +/- 3.3 mm and 3.3 +/- 4.2 mm, respectively. The postoperative change in maximum knee flexion angle was -2A degrees +/- 18A degrees. %26lt;br%26gt;Differences in individual posterior condylar offset with current PCL-retaining or PCL-substituting prostheses did not correlate with changes in knee flexion 1 year after TKA. We should recognize that correctly identifying which condyle affects the results of the TKA may be difficult with conventional radiographic techniques. %26lt;br%26gt;Level II, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

• 出版日期2013-9