Sportklinik Stuttgart, Taubenheimstr. 8, 70372, Stuttgart, Germany.
Orthopädische Universitätsklinik RWTH Aachen, Aachen, Germany.
Knee Surg Sports Traumatol Arthrosc. 2019 Mar;27(3):685-691. doi: 10.1007/s00167-018-4965-8. Epub 2018 May 21.
With the growing interest in resurfacing procedures, several new implants have been recently introduced for isolated patello-femoral joint arthroplasty (PFA). However, not much data are available for these new techniques or about the right indications for each type of implant.
Out of a retrospective cohort of 20 inlay PFA, 11 PFA with an elevated Insall-Salvati index and an increased patello-femoral congruence angle showed an initial satisfactory result, but presented thereafter with recurrent pain and "clunk" phenomena. They were all revised after a median time of 25 months (range 8-28 months) into an onlay technique PFA and analyzed for their failure mode and revision technique.
Clinical symptoms such as clunking, as well as abraded areas craniolateral of the inlay implant found intraoperatively, were the main observations of this study. The modified Insall-Salvati index (mISI) was significantly higher in the revised knees compared to the unrevised (median 1.8 versus 1.6; p = 0.041). VAS and KSS significantly improved after revision (median VAS reduction in pain of 4.0 points, median KSS improvement of 20.0 points; p < 0.05).
Patients with high-normal patellar height index or patella alta, as well as a craniolateral type of arthritis with additional lateralization, should be considered contra-indicated for an inlay technique PFA. They could be considered for a PFA system reaching further proximal into the distal femur. An onlay PFA can be an option for early revision of failed inlay implants. The clinical relevance of this study is that patella alta and patellar subluxation are more difficult to adjust for with an inlay PFJ component.
Level IV.
随着对表面置换术兴趣的增加，最近已经推出了几种新的植入物用于孤立的髌股关节置换术（PFA）。然而，这些新技术或每种植入物的正确适应证的数据并不多。
在回顾性队列的 20 例嵌体 PFA 中，11 例 Insall-Salvati 指数升高且髌股吻合角增加的 PFA 最初结果满意，但随后出现反复疼痛和“咔嗒”现象。在中位数为 25 个月（范围 8-28 个月）的时间后，所有患者均采用嵌体技术行 PFA 翻修，并分析其失败模式和翻修技术。
术中发现的咔嗒声等临床症状以及嵌体植入物颅侧磨损区域是本研究的主要观察结果。与未翻修组相比，翻修组的改良 Insall-Salvati 指数（mISI）明显更高（中位数 1.8 比 1.6；p=0.041）。翻修后 VAS 和 KSS 显著改善（疼痛 VAS 评分中位数降低 4.0 分，KSS 中位数改善 20.0 分；p<0.05）。
髌股高度指数高或高位髌骨，以及伴有外侧化的颅侧关节炎的患者，应被视为不适合嵌体技术 PFA 的指征。对于股骨远端更向近端延伸的 PFA 系统，他们可以被考虑。嵌体 PFA 可作为早期翻修失败嵌体植入物的选择。本研究的临床意义在于，髌股关节高位和髌骨半脱位更难通过嵌体 PFJ 组件进行调整。
IV 级。
