Kobayashi H, Akamatsu Y, Kumagai K, Kusayama Y, Aratake M, Saito T
Department of orthopaedic surgery, Yokohama city university, school of medicine, 3-9, Fukuura, Kanazawa, Yokohama, Kanagawa 236-0004, Japan.
Department of orthopaedic surgery, Yokohama city university, school of medicine, 3-9, Fukuura, Kanazawa, Yokohama, Kanagawa 236-0004, Japan.
Orthop Traumatol Surg Res. 2017 Apr;103(2):251-256. doi: 10.1016/j.otsr.2016.11.017. Epub 2017 Jan 11.
Coronal alignment is an important factor for the function and longevity of total knee arthroplasty (TKA). Coronal bowing of the lower extremity is common among Asians and it may pose a risk for malalignment of the lower leg and malposition of component.
We hypothesized that coronal bowing itself has a risk for malalignment of the lower leg and malposition of femoral/tibial components and that navigation TKA is beneficial for patients with coronal bowing. We investigated the incidence of femoral/tibial bowing in patients treated with TKA and compared the radiographic parameters between the navigation group and the conventional group. Additionally, the influence of coronal bowing on these radiographic parameters was investigated.
We enrolled 35 patients with knee osteoarthritis and 70 bilateral simultaneous TKAs. The patients underwent TKA with the use of a computer tomography-free navigation in one knee and conventional TKA in the contralateral knee. Preoperative coronal bowing were measured, and the subjects were divided into 2 subgroups, i.e. the bowing group and the non-bowing group. Lateral bowing was expressed as plus (+) and medial bowing was expressed as minus (-). Various radiographic parameters, including coronal bowing, lower leg alignment, component position, and outliers were compared between the navigation group and the conventional group.
Femoral bowing varied from -7.4° to 10.9° with an average of 3.0°. Tibial bowing varied from -4.1° to 4.6° with an average of 0.4°. The femoral component was placed more properly in the navigation group. Number of outlier regarding to the coronal femoral component angle to the femoral mechanical axis was 14 cases (37.8%) in the bowing group and 6 cases (18.2%) in the non-bowing group (P=0.04).
In conclusion, coronal femoral bowing has an important effect on femoral bone cut in TKA. The navigated TKA was more consistent than conventional TKA in aiding proper alignments of femoral component.
Level II, comparative prospective study.
冠状面排列是全膝关节置换术（TKA）功能及长期效果的重要因素。下肢冠状面弓形在亚洲人中较为常见，可能会导致小腿排列不齐及假体位置不当。
我们假设冠状面弓形本身会导致小腿排列不齐及股骨/胫骨假体位置不当，且导航全膝关节置换术对冠状面弓形患者有益。我们调查了接受全膝关节置换术患者的股骨/胫骨弓形发生率，并比较了导航组和传统组的影像学参数。此外，还研究了冠状面弓形对这些影像学参数的影响。
我们纳入了35例膝关节骨关节炎患者及70例双侧同时进行的全膝关节置换术。患者一侧膝关节采用无计算机断层扫描导航进行全膝关节置换术，对侧膝关节采用传统全膝关节置换术。测量术前冠状面弓形，并将受试者分为2个亚组，即弓形组和非弓形组。外侧弓形表示为正（+），内侧弓形表示为负（-）。比较导航组和传统组之间的各种影像学参数，包括冠状面弓形、小腿排列、假体位置和异常值。
股骨弓形范围为-7.4°至10.9°，平均为3.0°。胫骨弓形范围为-4.1°至4.6°，平均为0.4°。导航组股骨假体放置更合适。弓形组中，冠状面股骨假体角度与股骨机械轴相关的异常值有14例（37.8%），非弓形组有6例（18.2%）（P=0.04）。
总之，冠状面股骨弓形对全膝关节置换术中股骨截骨有重要影响。在辅助股骨假体正确排列方面，导航全膝关节置换术比传统全膝关节置换术更稳定。
二级，比较性前瞻性研究。
