Yoshihara Yasushi, Arai Yuji, Nakagawa Shuji, Inoue Hiroaki, Ueshima Keiichiro, Fujiwara Hiroyoshi, Oda Ryo, Taniguchi Daigo, Kubo Toshikazu
Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, 465 Kajiicho, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan.
Knee Surg Sports Traumatol Arthrosc. 2016 Aug;24(8):2512-6. doi: 10.1007/s00167-015-3601-0. Epub 2015 Apr 17.
Favourable long-term results after total knee arthroplasty (TKA) require appropriate soft tissue balance. However, the relationships between long-term results after TKA surgery and mediolateral laxities at extension and at 90° flexion remain unknown. This study therefore quantitatively assessed ligament balance at extension and at 90° knee flexion at least 10 years after primary TKA, as well as clarifying the relationships between long-term outcomes and mediolateral laxities.
This study included 49 knees (19 CR type and 30 PS type) of 33 patients followed up for at least 10 years after TKA at our hospital. Plain radiographs were obtained with about 150 N of varus or valgus stress using a Telos arthrometer at extension. At 90° flexion, epicondylar views were obtained under a 1.5-kg load and with about 10 kg of varus or valgus stress.
Lateral laxity of about 5° was observed in both extension and flexion, with total laxities of varus and valgus stress each less than 10°. Postoperative clinical outcomes were good, with significant improvements in extension angle, femorotibial angle, and KSS, and no loosening in any knee.
Good long-term results of TKA can be obtained with a lateral laxity of about 5°, equivalent to that of healthy knees.
III.
全膝关节置换术（TKA）后获得良好的长期效果需要适当的软组织平衡。然而，TKA手术后的长期效果与伸直位和90°屈曲位时的内外侧松弛度之间的关系尚不清楚。因此，本研究定量评估了初次TKA术后至少10年时伸直位和膝关节90°屈曲位时的韧带平衡情况，并阐明了长期结果与内外侧松弛度之间的关系。
本研究纳入了我院33例患者的49个膝关节（19个CR型和30个PS型），这些患者在TKA术后至少随访了10年。使用Telos关节测量仪在伸直位施加约150 N的内翻或外翻应力，获取X线平片。在90°屈曲位时，在1.5 kg负荷下并施加约10 kg的内翻或外翻应力，获取髁上视图。
伸直位和屈曲位均观察到约5°的外侧松弛，内翻和外翻应力的总松弛度均小于10°。术后临床效果良好，伸直角度、股胫角和膝关节协会评分（KSS）均有显著改善，且所有膝关节均无松动。
TKA术后可获得良好的长期效果，外侧松弛度约为5°，与健康膝关节相当。
III级。
