BACKGROUND Radiographic imaging is an important tool to assess osteoarthritis (OA). Lateral compartment osteoarthritis (valgus OA) usually starts with cartilage degeneration along the posterior aspect of the lateral femoral condyle. There is evidence that the posterior-anterior (PA)-flexed view is more sensitive when diagnosing early stages of valgus OA compared to the anterior-posterior (AP) view. The current paper analyzes the value of the PA-flexed view for patients scheduled for total knee arthroplasty (TKA). METHODS Radiographs of 134 valgus knees were assessed prior to TKA. The minimal joint space width (minJSW) was measured on AP and PA-flexed views. The extent of mechanical deformity was measured on hip to ankle standing films. RESULTS 49 (36.6%) AP views showed Kellgren and Lawrence (K/L)-grade 4 osteoarthritis in the lateral compartment, 82 (63.4%) showed grade 3 or less. The PA-flexed view resulted in an increased K/L-grading to grade 4 for 53 knees (62.4%) that were considered grade 3 or less on standard AP-radiographs. There was a significant differences between lateral minJSW on AP and PA-flexed view for patients with up to 10 degrees of mechanical valgus deformity (p < 0.001), as well as 11 to 15 degrees of mechanical deformity (p = 0.021). Only knees with severe deformity of more than 15 degrees did not show a difference in minJSW between PA-flexed view and AP view (p = 0.345). CONCLUSIONS The PA-flexed view is superior to the standard AP view in quantifying the extent of valgus OA in patients with zero to fifteen degrees of valgus deformity. It is recommended for the initial assessment of patients with valgus osteoarthritis and better documents the extent of osteoarthritis prior to TKA.

中文翻译：

---

前后弯曲视图对于评估外翻性骨关节炎至关重要。134例外翻膝盖的前瞻性研究。

背景技术射线照相成像是评估骨关节炎（OA）的重要工具。外侧室骨关节炎（外翻OA）通常始于沿股lateral外侧后方的软骨退行性变。有证据表明，在诊断外翻OA的早期阶段时，与前-后（AP）视图相比，后-前（PA）弯曲视图更为敏感。当前的论文分析了PA屈曲视图对于计划进行全膝关节置换术（TKA）的患者的价值。方法在进行TKA之前，对134个外翻膝盖的X线照片进行了评估。在AP和PA弯曲视图上测量最小关节间隙宽度（minJSW）。机械变形的程度在髋部至踝部的站立膜上测量。结果49（36。6％）的AP观察显示侧房室的Kellgren和Lawrence（K / L）4级骨关节炎，82级（63.4％）显示3级或以下。PA弯曲的视图导致53个膝盖（62.4％）的K / L分级增加到4级，在标准AP射线照相上被认为是3级或以下。机械外翻畸形程度最高为10度（p <0.001）以及机械畸形程度为11至15度（p = 0.021）的患者，AP和PA屈曲侧位minJSW之间存在显着差异。仅膝关节严重畸形超过15度时，PA屈曲视角和AP视角之间的minJSW差异没有显示（p = 0.345）。结论在量化外翻畸形为0到15度的患者中，PA屈曲视角优于标准AP视角。