McGrory James E, Trousdale Robert T, Pagnano Mark W, Nigbur Michael
Naval Medical Center Portsmouth, Portsmouth, VA, USA.
Clin Orthop Relat Res. 2002 Nov(404):196-202. doi: 10.1097/00003086-200211000-00032.
Whether a preoperative long leg radiograph taken with the patient standing helps the surgeon reproduce a normal mechanical axis after total knee arthroplasty is unknown. The purpose of the current study was to evaluate whether a preoperative long leg radiograph helps to restore normal limb alignment after total knee arthroplasty. Ninety-four patients (124 primary total knee arthroplasties) were randomized to either receive or not receive a preoperative long leg standing radiograph. Patients with previous hip or ankle surgery, femoral or tibial fracture, deformity of 15 degrees or greater, or those who were obese (body weight index > 40 kg/m2) were excluded. All arthroplasties were done by one surgeon. The angle of distal femoral resection varied between 5 degrees and 8 degrees (mean, 6.2 degrees) among patients with long leg radiographs. In patients without long leg radiographs, the distal femur was cut at 5 degrees. Long leg radiographs were obtained postoperatively in all patients and the mechanical axis was assessed, first by whether the mechanical axis fell within the central third of the knee, and second by the distance in millimeters that the mechanical axis fell from the knee center. No significant difference in the postoperative mechanical axis was detected between the two groups. Eighty-six percent of the patients with long leg preoperative radiographs and 92% of the patients without long leg preoperative radiographs had the mechanical axis pass through the central (1/3) of the knee. Preoperative hip to ankle long leg radiographs taken with the patient standing did not significantly help to obtain a neutral mechanical axis during routine total knee arthroplasty.
患者站立位时术前拍摄的长腿X线片是否有助于外科医生在全膝关节置换术后重现正常的机械轴尚不清楚。本研究的目的是评估术前长腿X线片是否有助于全膝关节置换术后恢复正常的肢体对线。94例患者（124例初次全膝关节置换术）被随机分为接受或不接受术前站立位长腿X线片检查两组。排除既往有髋关节或踝关节手术史、股骨或胫骨骨折、畸形15度或以上的患者，或肥胖患者（体重指数>40kg/m2）。所有关节置换术均由一名外科医生完成。有长腿X线片的患者中，股骨远端截骨角度在5度至8度之间（平均6.2度）。没有长腿X线片的患者，股骨远端截骨角度为5度。所有患者术后均获得长腿X线片并评估机械轴，首先评估机械轴是否落在膝关节中央三分之一范围内，其次评估机械轴距膝关节中心的毫米数。两组术后机械轴无显著差异。术前有长腿X线片的患者中86%以及术前没有长腿X线片的患者中92%的机械轴穿过膝关节中央（1/3）。患者站立位时术前髋关节至踝关节的长腿X线片在常规全膝关节置换术中对获得中立的机械轴并无显著帮助。
