Sint Maartenskliniek Research, Sint Maartenskliniek, P.O. box 9011, 6500 GM, Nijmegen, The Netherlands.
Department of Orthopedic Surgery, Sint Maartenskliniek, Nijmegen, The Netherlands.
Knee Surg Sports Traumatol Arthrosc. 2019 Nov;27(11):3614-3625. doi: 10.1007/s00167-019-05474-7. Epub 2019 Mar 22.
During total knee arthroplasty (TKA), an orthopaedic surgeon is focused on soft-tissue balance in extension (0°) and in flexion (90°). Patients with instability problems of the knee often report a feeling of instability during daily life activities, at around 30° knee flexion. There are no reference values available for knee laxity of healthy subjects in mid-flexion (30°) and flexion (90°) for comparison with the TKA population. Therefore, the aim was to quantify varus and valgus knee laxity in extension, mid-flexion and flexion in the asymptomatic native knee.
In 40 healthy volunteers matched for age, gender and BMI with the TKA-population, varus and valgus knee laxity in extension (0°), mid-flexion (30°) and flexion (90°) was measured on low-dose radiographs. For each subject, one randomly selected knee was stressed in extension, mid-flexion and flexion (with 15 Nm) using a stress device.
Varus laxity in mid-flexion was higher than in extension and flexion (p < 0.01). Valgus laxity tended to be highest in mid-flexion laxity; however, no differences in knee laxity between flexion angles were seen (n.s.). Varus knee laxity in extension was higher in females than in males (p < 0.05).
Mid-flexion laxity in the native knee is more prominent on the lateral side of the knee, while the medial side is more stable and constrained. Varus knee laxity in extension was shown to be higher in females than in males.
Prognostic Level II.
在全膝关节置换术（TKA）中，矫形外科医生专注于膝关节在伸直位（0°）和屈曲位（90°）时的软组织平衡。膝关节不稳定的患者在日常生活活动中，通常在膝关节屈曲约 30°时会感到不稳定。目前尚无健康受试者在膝关节中-屈曲位（30°）和屈曲位（90°）时的膝关节松弛度的参考值，以便与 TKA 人群进行比较。因此，本研究旨在定量测量无症状自然膝关节在伸直位、中-屈曲位和屈曲位时的内、外翻松弛度。
在 40 名与 TKA 人群年龄、性别和 BMI 相匹配的健康志愿者中，在低剂量 X 线片上测量膝关节在伸直位（0°）、中-屈曲位（30°）和屈曲位（90°）时的内、外翻松弛度。对于每个受试者，使用应力装置在伸展、中-屈曲和屈曲位（施加 15 Nm）下对一只随机选择的膝关节进行受力。
中-屈曲位的内翻松弛度高于伸展位和屈曲位（p<0.01）。外翻松弛度在中-屈曲位时似乎最高，但在不同的屈曲角度之间没有看到膝关节松弛度的差异（无统计学意义）。女性膝关节在伸展位时的内翻松弛度高于男性（p<0.05）。
自然膝关节的中-屈曲位时，膝关节外侧的松弛度更为明显，而内侧则更为稳定和受限。伸展位时的膝关节内翻松弛度在女性中高于男性。
预后 II 级。
