King G J, Itoi E, Risung F, Niebur G L, Morrey B F, An K N
Hand and Upper Limb Centre, University of Western Ontario, London, Canada.
Acta Orthop Scand. 1993 Dec;64(6):657-63. doi: 10.3109/17453679308994592.
We investigated the effect of simulated muscle loading and the contribution of the radial head to stability of the Norway elbow in 6 cadavers using an electromagnetic tracking device. The kinematics of the elbow after implantation of the prosthesis were similar to the intact elbow in their valgus-varus orientation, however, the forearms were slightly externally rotated, probably due to a small amount of external rotation of the humeral components at the time of implantation. The valgus-varus laxity limit of the implants were greater than in the intact specimens averaging 8.0 and 5.6 degrees, respectively. Simulated muscle loading stabilized both the intact and the Norway elbows. Excision of the radial head after implant arthroplasty increased their valgus-varus laxity, suggesting that preservation of the radial head may be indicated if it is not too severely involved by the underlying disease process. The laxity permitted by the prosthesis articulation is greater than that measured after implantation of the Norway arthroplasty. This suggests that the prosthesis may behave as an unconstrained arthroplasty. This should minimize the stress experienced by the bone-cement interface and may reduce the incidence of loosening. The laxity of the elbows after joint arthroplasty were only slightly greater than normal, possibly explaining the low incidence of prosthesis dislocation which has been observed with clinical use.
我们使用电磁跟踪设备，在6具尸体上研究了模拟肌肉负荷以及桡骨头对挪威式肘关节稳定性的影响。植入假体后肘关节的运动学在内外翻方向上与完整肘关节相似，然而，前臂略有外旋，这可能是由于植入时肱骨组件有少量外旋。植入物的内外翻松弛极限大于完整标本，平均分别为8.0度和5.6度。模拟肌肉负荷使完整肘关节和挪威式肘关节都得到了稳定。植入关节成形术后切除桡骨头会增加其内外翻松弛度，这表明如果桡骨头未被潜在疾病过程严重累及，可能需要保留它。假体关节允许的松弛度大于挪威关节成形术植入后测量的松弛度。这表明该假体可能表现为非限制性关节成形术。这应能使骨水泥界面所承受的应力最小化，并可能降低松动的发生率。关节成形术后肘关节的松弛度仅略大于正常情况，这可能解释了临床使用中观察到的假体脱位发生率较低的原因。
