Watanabe Yoshinobu, Terashima Yuichiro, Takenaka Nobuyuki, Kobayashi Makoto, Matsushita Takashi
Department of Orthopaedic Surgery, Teikyo University School of Medicine, Tokyo, Japan.
J Orthop Trauma. 2007 Aug;21(7):456-61. doi: 10.1097/BOT.0b013e318126bb56.
To measure the intramedullary oxygen tension of the proximal femur after a femoral neck fracture and to evaluate the usefulness of that monitoring for prediction of subsequent avascular necrosis.
Prospective case series with comparison group.
University hospital.
Measurement of intramedullary oxygen tension of the femoral head and neck during internal fixation using the Hansson hook-pin system.
Intramedullary oxygen tension was measured directly during surgery in 17 patients with 18 femoral neck fractures treated by internal fixation between October 2000 and February 2002. The intramedullary oxygen tension was measured by using polarographic oxygen electrodes and an oxygen monitor at four points: (A) 1 cm distal from the joint surface; (B) 1 cm proximal from the fracture site; (C) 1 cm distal from the fracture site; and (D) 1 cm proximal from the lateral wall. The presence or absence of avascular necrosis was evaluated by magnetic resonance imaging (MRI) at 2, 6, and 12 months after surgery.
MRI evaluation showed 11 fractures healed without complications, and 7 fractures developed avascular necrosis. We found significant differences in the distribution of intramedullary oxygen tension of the femoral head between points A (1 cm from the joint surface) and B (1 cm proximal from the fracture site) in those patients who developed avascular necrosis (P = 0.039); that is the oxygen tension was lower at point A than at point B. In contrast, in those patients who did not develop avascular necrosis there was no significant differences between point A and B were found (P = 0.059). The sensitivity and specificity for prediction of avascular necrosis were 1.0 and 0.82 (Fischer exact probability test, P = 0.002), respectively, when the cut-off level of oxygen tension differences between points A and B was set at 3.1 mm Hg.
We believe that this method of measuring intramedullary oxygen tension is simpler and less invasive than other currently used methods and has the possibility for intraoperatively identifying a risk group that can develop a late segmental collapse of the femoral head secondary to avascular necrosis.
测量股骨颈骨折后股骨近端的髓内氧张力，并评估该监测对于预测随后发生的股骨头缺血性坏死的有效性。
设有对照组的前瞻性病例系列研究。
大学医院。
使用汉森钩针系统在内固定手术过程中测量股骨头和股骨颈的髓内氧张力。
在2000年10月至2002年2月期间，对17例接受内固定治疗的18处股骨颈骨折患者在手术过程中直接测量髓内氧张力。使用极谱氧电极和氧监测仪在四个点测量髓内氧张力：（A）距关节面1厘米远；（B）距骨折部位近端1厘米；（C）距骨折部位远端1厘米；（D）距外侧壁近端1厘米。在术后2、6和12个月通过磁共振成像（MRI）评估是否存在缺血性坏死。
MRI评估显示11处骨折愈合且无并发症，7处骨折发生了缺血性坏死。我们发现发生缺血性坏死的患者中，在点A（距关节面1厘米）和点B（距骨折部位近端1厘米）之间股骨头髓内氧张力分布存在显著差异（P = 0.039）；即点A处的氧张力低于点B处。相比之下，未发生缺血性坏死的患者中，点A和点B之间未发现显著差异（P = 0.059）。当将点A和点B之间氧张力差异的截断水平设定为3.1毫米汞柱时，预测缺血性坏死的敏感性和特异性分别为1.0和0.82（费舍尔精确概率检验，P = 0.002）。
我们认为这种测量髓内氧张力的方法比目前使用的其他方法更简单且侵入性更小，并且有可能在术中识别出可能因缺血性坏死而发生股骨头晚期节段性塌陷的风险组。
