Ishii Orthopaedic and Rehabilitation Clinic, 1089 Shimo-Oshi, Gyoda, Saitama, 361-0037, Japan.
Knee Surg Sports Traumatol Arthrosc. 2012 Oct;20(10):1988-93. doi: 10.1007/s00167-011-1783-7. Epub 2011 Nov 25.
This randomized, prospective study was performed to evaluate changes in varus-valgus laxity over time and to evaluate the relationship between laxity and retention of the posterior cruciate ligament.
Sixty knees of 60 patients with osteoarthritis received mobile-bearing prostheses. Thirty patients received posterior cruciate ligament-retaining prostheses (average follow-up, 75 months), and 30 patients received posterior cruciate ligament-sacrificing prostheses (average follow-up, 78 months). Varus-valgus laxity was measured with the knee in extension at 6 months, 1 and 2 years after surgery, and at final follow-up examination (average, 77 months).
Varus laxity measurements for patients with posterior cruciate ligament-retaining prostheses at 6 months, 1 year, 2 years, and final examination were 3.7° ± 1.2°, 4.0° ± 1.3°, 4.1° ± 1.7°, and 4.2° ± 1.3°, respectively; corresponding valgus laxity measurements were 3.5° ± 1.1°, 3.5° ± 1.3°, 3.5° ± 1.1°, and 3.6° ± 1.1°, respectively. Varus laxity measurements for patients with posterior cruciate ligament-sacrificing prostheses at 6 months, 1 year, 2 years, and final examination were 4.3° ± 1.9°, 4.3° ± 1.9°, 4.3° ± 1.8°, and 4.4° ± 1.7°, respectively; corresponding valgus laxity measurements were 3.7° ± 1.3°, 3.4° ± 1.3°, 3.5° ± 1.1°, and 3.6° ± 1.3°, respectively.
There were no significant differences in varus and valgus laxities between the two groups. This study demonstrates that coronal laxity does not change over time in either type of knee prostheses and that the posterior cruciate ligament does not affect coronal stability during varus-valgus stress.
Prognostic study, See the Guidelines for Authors for a complete description of levels of evidence, Level I.
本随机前瞻性研究旨在评估随时间推移的内翻-外翻松弛度变化，并评估松弛度与后交叉韧带保留之间的关系。
60 例骨关节炎患者的 60 膝接受了活动平台假体。30 例患者接受了保留后交叉韧带的假体（平均随访 75 个月），30 例患者接受了牺牲后交叉韧带的假体（平均随访 78 个月）。术后 6 个月、1 年和 2 年以及最终随访检查时（平均 77 个月），在膝关节伸展位测量内翻-外翻松弛度。
保留后交叉韧带假体患者的内翻松弛度测量值在术后 6 个月、1 年、2 年和最终检查时分别为 3.7°±1.2°、4.0°±1.3°、4.1°±1.7°和 4.2°±1.3°；相应的外翻松弛度测量值分别为 3.5°±1.1°、3.5°±1.3°、3.5°±1.1°和 3.6°±1.1°。牺牲后交叉韧带假体患者的内翻松弛度测量值在术后 6 个月、1 年、2 年和最终检查时分别为 4.3°±1.9°、4.3°±1.9°、4.3°±1.8°和 4.4°±1.7°；相应的外翻松弛度测量值分别为 3.7°±1.3°、3.4°±1.3°、3.5°±1.1°和 3.6°±1.3°。
两组间内翻和外翻松弛度无显著差异。本研究表明，两种膝关节假体的冠状松弛度均不会随时间而改变，后交叉韧带在内外翻应力下不会影响冠状稳定性。
预后研究，详见作者指南中对证据水平的完整描述，I 级。
