Maeno Shinichi, Kondo Makoto, Niki Yasuo, Matsumoto Hideo
Department of Orthopedic Surgery, Keio University Hospital, Tokyo, Japan.
Clin Orthop Relat Res. 2006 Nov;452:265-9. doi: 10.1097/01.blo.0000224049.56130.86.
Patella baja developed in seven knees in five patients after posterior stabilized total knee arthroplasties when the patella became impinged against the tibial component. Patellar replacement was performed in four knees, and all patients were able to achieve deep flexion postoperatively. The mean followup was 50 months (range, 24-73 months) for these patients. The mean Insall-Salvati ratio changed from 0.87 (range, 0.70-1) immediately postoperatively to 0.66 (range, 0.55-0.84) at followup. Patellar erosion occurred in three knees without patellar replacements, accompanied by pain and reduced range of flexion. The four knees with patellar replacements showed marked erosion of the patellar component or the patella, but all remained asymptomatic. Achieving deep flexion in addition to patella baja was thought to be a key element. Patellar replacement, joint line preservation, shaving the anterior portion of the tibial component, preventing surgically induced patella baja, and careful radiographic followup should be considered when deep flexion is achieved in a knee with patella baja after a total knee arthroplasty.
在五名患者的七膝后稳定型全膝关节置换术后，当髌骨撞击胫骨部件时出现了低位髌骨。对四膝进行了髌骨置换，所有患者术后均能实现深度屈曲。这些患者的平均随访时间为50个月（范围24 - 73个月）。平均Insall - Salvati比率从术后即刻的0.87（范围0.70 - 1）降至随访时的0.66（范围0.55 - 0.84）。三膝未进行髌骨置换出现了髌骨侵蚀，伴有疼痛和屈曲范围减小。进行了髌骨置换的四膝显示髌骨部件或髌骨有明显侵蚀，但均无症状。除低位髌骨外实现深度屈曲被认为是关键因素。当全膝关节置换术后低位髌骨的膝关节实现深度屈曲时，应考虑髌骨置换、保留关节线、磨削胫骨部件前部、防止手术导致的低位髌骨以及仔细的影像学随访。
