Outcomes of Cementless-Backed Patellar Components.

Abstract

Because of the early follow-up positive outcomes with cementless fixation, continued evaluations need to be performed to ensure longer-term efficacy. Additionally, although many studies report on the results of femoral and tibial component fixation, few studies report specifically on patellar outcomes. Therefore, the purpose of this study was to report on the: (1) implant survivorship; (2) complications; and (3) radiographic outcomes in a large cohort of patients who received cementless total knee arthroplasties (TKAs), with particular attention to the patellar component. A total of 261 patients who underwent cementless TKA by a single, high-volume academic surgeon were studied. Patients had a mean age of 66 years and were distributed between 192 women (74%) and 69 men. All patients received the same cementless tibial, femoral, and patellar components. Mean follow-up period was 4.5 years (range, 4-5 years). Primary outcomes evaluated included all postoperative complications, with particular emphasis on the patellar component. Only one patellar loosened leading to a patellar aseptic loosening rate of 0.3% (1 of 261). The one patellar loosening was the component being dislodged after a manipulation under anesthesia (MUA) at 6 weeks. This was revised to a cemented component and the patient is doing well 4 years later. A second patient experienced a patellar tendon rupture, later surgically repaired. Another patient sustained a patella fracture that was managed nonoperatively. The fracture healed by 1 year and the patient continued to have an otherwise successful outcome, now at 2 years follow-up. No progressive radiolucencies, subsidence, or changes in initial postoperative axial alignment were observed at final follow-up. The results from this study highlight a 98% success rate at mean 4.5 years follow-up in a large cohort of patients with a diverse spread of demographic details. Specific to the patella, only one patient experienced an adverse event, which was managed nonoperatively. Therefore, based on this data, patellar fixation in cementless TKA can be considered a safe technique.