Sharma Gaurav, Liu David, Malhotra Rajesh, Zhou Yi Xin, Akagi Masao, Kim T K
Joint Reconstruction Center, Seoul National University Bundang Hospital, Seongnam, Gyeonggi-do, Republic of Korea.
Gold Coast Centre for Bone and Joint Surgery, John Flynn Private Hospital, Gold Coast, Queensland, Australia.
JB JS Open Access. 2017 May 18;2(2):e0014. doi: 10.2106/JBJS.OA.16.00014. eCollection 2017 Jun 26.
Anatomical variation may represent a challenge in achieving a close fit between a prosthesis and a patient's osseous geometry in total knee arthroplasty (TKA). The purposes of this study were to determine whether the shape of the distal part of the femur differs among ethnicities, whether these differences affect the fit of the femoral component of a standard prosthesis, and whether the additional availability of a femoral component with a reduced mediolateral dimension for the same anteroposterior dimension improves femoral component fit across ethnicities.
Femoral dimensions were measured intraoperatively during 967 TKAs performed using the same type of prosthesis in patients of 5 different ethnicities. Aspect ratios were calculated to determine whether the shapes of the femora differed among ethnicities. The component fit ("perfect," overhang, or underhang) when only standard prostheses were available was compared with the fit when both standard and narrow prostheses were available in all ethnic groups. This enabled us to determine whether the femoral component fit was improved by the additional availability of the narrow version.
Wide variations in shape were found among ethnicities as were variations among individuals of the same ethnicity. Differences in shape among ethnicities influenced the rate of overhang. However, overhang was more frequent at the trochlear than at the condylar level across all ethnicities. The availability of both the standard and the narrow femoral components improved the rate of a perfect fit in women in 3 of the 5 ethnic groups and reduced the overhang rate in women in all 5 of the ethnic groups. In contrast, only modest improvements in femoral component fit, which were not statistically significant, were seen in men.
The shape of the distal part of the femur varies not only among ethnicities but also within ethnic groups, leading to a high prevalence of overhang when only standard prostheses are available. The additional availability of a femoral component with a reduced mediolateral dimension for the same anteroposterior size can reduce overhang and improve component fit across ethnicities.
在全膝关节置换术（TKA）中，解剖变异可能是实现假体与患者骨几何形状紧密贴合的一项挑战。本研究的目的是确定不同种族之间股骨远端的形状是否存在差异，这些差异是否会影响标准假体股骨部件的贴合度，以及对于相同的前后径，额外提供一种内外侧尺寸减小的股骨部件是否能改善不同种族的股骨部件贴合度。
在使用同类型假体对5个不同种族的患者进行的967例TKA手术中，术中测量股骨尺寸。计算纵横比以确定不同种族之间股骨形状是否存在差异。比较所有种族中仅使用标准假体时的部件贴合情况（“完美”、悬垂或不足）与同时有标准假体和窄型假体时的贴合情况。这使我们能够确定窄型假体的额外提供是否改善了股骨部件的贴合度。
不同种族之间以及同一种族个体之间均发现形状存在广泛差异。种族之间的形状差异影响了悬垂率。然而，在所有种族中，滑车处的悬垂比髁部更常见。标准和窄型股骨部件的同时提供提高了5个种族中3个种族女性的完美贴合率，并降低了所有5个种族女性的悬垂率。相比之下，男性的股骨部件贴合度仅略有改善，且无统计学意义。
股骨远端的形状不仅在不同种族之间存在差异，在同一种族内部也存在差异，这导致仅使用标准假体时悬垂的发生率较高。对于相同的前后尺寸，额外提供一种内外侧尺寸减小的股骨部件可以减少悬垂并改善不同种族的部件贴合度。
