Orthopaedic and Trauma Surgery Center, University Medical Center Mannheim of University Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany,
Arch Orthop Trauma Surg. 2014 Jan;134(1):91-7. doi: 10.1007/s00402-013-1896-1. Epub 2013 Nov 28.
Patellofemoral related complications after total knee arthroplasty (TKA) remain clinically relevant. The hypothesis of the present study was that the patellar height changes more than 10% of its preoperative height after TKA. Possible influences of age, gender, side and navigation system on patellar height were evaluated separately in subgroups.
A total of 107 knees were enrolled after primary TKA. The patellar height was determined for each patient preoperatively, 1 week and 1 year postoperatively on routinely performed standing lateral view radiographs at 30° knee flexion. Insall-Salvati index (ISI), modified Insall-Salvati index (MIS) as well as Miura-Kawamura index (MKI) were determined for the whole cohort.
One week after TKA the ISI, MIS and MKI changed by more than 10% in 24 (22%), 33 (30%) and 54 (50%) cases, respectively. Moreover, the 1 year follow-up revealed a decrease or increase of ISI in 30 (28%), MIS in 47 (44 %) and MK in 65 (61%) knees. The frequency of patella alta, norma and baja preoperatively as well as 1 week and 1 year postoperatively were not significantly different. Significant differences of patellar height changes were not noted between the defined subgroups.
The present study demonstrates that TKA leads, at 1 week and 1 year follow-up, to patellar height alteration more than 10% in a significant number of knee joints. However, with the use of ISI and MIS the changes of patellar height did not exceed the defined thresholds to be classified as patella alta or baja.
全膝关节置换术后髌股相关并发症仍然具有临床意义。本研究的假设是，全膝关节置换术后髌股高度比术前增加 10%以上。分别对年龄、性别、侧别和导航系统对髌骨高度的可能影响进行亚组分析。
共纳入 107 例初次 TKA 患者。每位患者在术前、术后 1 周和 1 年时分别在常规站立侧位 30°膝关节屈曲位 X 线片上测量髌骨高度。计算 Insall-Salvati 指数（ISI）、改良 Insall-Salvati 指数（MIS）和 Miura-Kawamura 指数（MKI）。
TKA 后 1 周时，ISI、MIS 和 MKI 分别有 24 例（22%）、33 例（30%）和 54 例（50%）改变超过 10%。此外，1 年随访时，ISI 下降或升高 30 例（28%）、MIS 下降或升高 47 例（44%）、MK 下降或升高 65 例（61%）。术前、术后 1 周及 1 年髌骨高位、正常位和低位的发生率无显著差异。各亚组间髌骨高度变化的差异无统计学意义。
本研究表明，TKA 导致膝关节在 1 周和 1 年随访时，髌骨高度发生超过 10%的改变。然而，使用 ISI 和 MIS 时，髌骨高度的变化并未超过定义的高位或低位阈值。
