Stoller D W, Markolf K L, Zager S A, Shoemaker S C
Clin Orthop Relat Res. 1983 Apr(174):172-80.
Changes in torsional knee laxity, after subjects ran 3.5 miles during a 30-minute period, were studied in 13 subjects. The effects of ice and ultrasonographic treatments on these laxity changes were then investigated. Knee laxity was determined by measuring torque versus rotation responses of the tibia at 90 degrees of knee flexion. Total rotational laxity of the tibia was tabulated at +/- 10 newton-meters of applied torque. There were significant increases in postexercise laxities over preexercise levels for internal and external tibial rotation. Postexercise laxity changes followed a uniform time course of recovery. The maximum postexercise laxity represented a mean increase of 14% over pre-exercise levels, with a mean recovery time of 52.4 minutes and a standard deviation of 17.8 minutes. The application of ten-minute treatments of either ice or ultrasonography significantly reduced postexercise recovery times, to 20.0 +/- 4.6 SD and 20.9 +/- 6.4 SD, respectively. A common clinical assumption, that cold and heat have opposite effects on knee laxity, was found invalid. In the authors' study, ice and ultrasonography had equivalent effects in accelerating the return to pre-exercise laxities. No laxity changes were observed in unexercised subjects, with either ice or ultrasonographic treatments. The time course of laxity recovery and the subsequent effects of heat and ice are important clinically. Immediately after injury, both knees are more lax than normal, and after approximately one hour, recovery to pre-exercise laxity levels will be complete for the uninjured leg. Ice (or ultrasonography) will shorten this time to 20 minutes. If these recovery time courses are recognized and taken into account, a more accurate diagnosis can be made during this "golden opportunity" period before pain and swelling ensue. The fact that ice and ultrasonography have identical effects on the time course of recovery in the exercised knee raises new questions and suggests additional areas for future work in the recently developing field of sports medicine biomechanics.
对13名受试者在30分钟内跑完3.5英里后膝关节扭转松弛度的变化进行了研究。随后研究了冰敷和超声治疗对这些松弛度变化的影响。通过测量膝关节屈曲90度时胫骨的扭矩与旋转反应来确定膝关节松弛度。在施加±10牛顿米的扭矩时，记录胫骨的总旋转松弛度。运动后胫骨内旋和外旋的松弛度较运动前水平有显著增加。运动后松弛度的变化遵循统一的恢复时间进程。运动后最大松弛度比运动前水平平均增加了14%，平均恢复时间为52.4分钟，标准差为17.8分钟。进行10分钟的冰敷或超声治疗可显著缩短运动后的恢复时间，分别缩短至20.0±4.6标准差和20.9±6.4标准差。一个常见的临床假设，即冷和热对膝关节松弛度有相反的影响，被发现是无效的。在作者的研究中，冰敷和超声治疗在加速恢复到运动前松弛度方面具有同等效果。未运动的受试者在接受冰敷或超声治疗后未观察到松弛度变化。松弛度恢复的时间进程以及随后热和冰的影响在临床上很重要。受伤后立即，双侧膝关节都比正常时更松弛，大约一小时后，未受伤的腿将恢复到运动前的松弛度水平。冰敷（或超声治疗）将把这个时间缩短到20分钟。如果认识到并考虑这些恢复时间进程，在疼痛和肿胀出现之前的这个“黄金时机”期间可以做出更准确的诊断。冰敷和超声治疗对运动后膝关节恢复时间进程具有相同影响这一事实提出了新的问题，并为运动医学生物力学这一新兴领域的未来工作指明了更多方向。
