Department of Orthopaedic Surgery and Traumatology, Kantonsspital Bruderholz, 4101, Bruderholz, Switzerland.
Knee Surg Sports Traumatol Arthrosc. 2011 May;19(5):747-52. doi: 10.1007/s00167-010-1346-3. Epub 2010 Dec 11.
Excessive varus and valgus stress forces during arthroscopy might exceed minimal compressive strength of cancellous bone. In extreme cases, this could lead to post-arthroscopic osteonecrosis. It was our purpose to measure the valgus and varus stress forces during arthroscopy and draw conclusions on the development of osteonecrosis.
On 24 consecutive patients undergoing arthroscopy, the maximum varus and valgus stress forces (N) were measured in vivo using a strain gauge mounted to a leg holder. The forces (N) and contact stresses (kPa) on the femoral condyles were calculated based on the measured acting lateral force at the femur fixation based on the lever principle.
The maximum contact stress during varus on the medial condyle was significantly lower in patients with intact meniscus (mean ± standard error of the mean: 243 ± 29 kPa) than in patients with meniscus-deficient knees (520 ± 61 kPa; P < 0.01). A similar finding was obtained for the maximum contact stress during valgus on the lateral condyle: 630 ± 72 kPa in patients with intact meniscus compared to 2,173 ± 159 kPa in patients with meniscus-deficient knees (P < 0.01). In 19 patients (79%), the maximum contact stress was higher during valgus than during varus. The maximum contact stress on the lateral condyle during valgus was significantly higher for more experienced surgeons (P = 0.01).
The maximum contact stresses in knees with intact menisci did not exceed the critical threshold of the compressive strength in cancellous bone. However, the maximum contact stresses in meniscus-deficient knees were frequently higher than the threshold. However, these stresses were much lower than those during daily activities and therefore unlikely to lead to post-arthroscopic osteonecrosis.
Diagnostic study, Level II.
关节镜检查过程中过度的内翻和外翻应力可能超过松质骨的最小抗压强度。在极端情况下，这可能导致关节镜检查后骨坏死。我们的目的是测量关节镜检查过程中的外翻和内翻应力，并得出关于骨坏死发展的结论。
对 24 例连续接受关节镜检查的患者，使用安装在腿部固定器上的应变计在体内测量最大内翻和外翻应力（N）。根据杠杆原理，基于测量的股骨固定处的作用横向力，计算股骨髁上的力（N）和接触应力（kPa）。
内侧髁在进行内翻时的最大接触应力在半月板完整的患者中明显低于半月板缺失的患者（平均值±均数标准误差：243±29kPa）（P<0.01）。在外侧髁进行外翻时的最大接触应力也得到了类似的发现：半月板完整的患者为 630±72kPa，而半月板缺失的患者为 2173±159kPa（P<0.01）。在 19 例患者（79%）中，外翻时的最大接触应力高于内翻时。外侧髁在进行外翻时的最大接触应力在经验更丰富的外科医生中更高（P=0.01）。
半月板完整的膝关节中的最大接触应力未超过松质骨抗压强度的临界阈值。然而，半月板缺失的膝关节中的最大接触应力经常高于阈值。然而，这些应力远低于日常活动中的应力，因此不太可能导致关节镜检查后骨坏死。
诊断研究，II 级。
