scholarly journals All-Polyethylene Tibial Component Does Not Affect Survivorship of Medial Unicompartmental Knee Arthroplasty at Mid-Term Follow-Up

Author(s):  
Michele Gagliardi ◽  
Francesco Zambianchi ◽  
Alois Franz ◽  
Vitantonio Digennaro ◽  
Fabio Catani

AbstractThe present study's primary aim was to determine the survivorship of a large cohort of patients implanted with a single design all-polyethylene tibial component medial unicompartmental knee arthroplasty (UKA). Its secondary purpose was to investigate the reasons underlying implant failure, with specific attention to component positioning and limb alignment. Between 2007 and 2013, 166 patients underwent medial UKA with a single design all-polyethylene tibial component at two centers. Preoperatively and postoperatively, patients were administered clinical outcome scores and radiographic information were collected. Postoperative complications and causes of revision were recorded. A total of 140 patients (80 in Center A and 60 in Center B) who underwent all-polyethylene tibial component medial UKA (82 cases in Center A and 60 in Center B) were taken into account. Kaplan–Meier cumulative survivorship of implants was 96.5% (confidence interval [CI]: 91.7–98.6%) at an average follow-up of 61.1 months. Tibial aseptic loosening was accounted for failure in one case, while no correlation was found between implant positioning and failure. Two revisions were performed in Center A and three in Center B. Slight correction of the preoperative varus deformity was performed at both centers. All-polyethylene tibial component UKA provided satisfactory clinical and functional outcome, with excellent survival rate in the early and mid-term follow-up. Continued patient follow-up is needed to determine long-term survivorship of the examined UKA model.

2019 ◽  
Vol 33 (02) ◽  
pp. 180-189 ◽  
Author(s):  
Giuseppe Gianluca Costa ◽  
Mirco Lo Presti ◽  
Alberto Grassi ◽  
Giuseppe Agrò ◽  
Sergio Cialdella ◽  
...  

AbstractLong-term results of unicompartmental knee arthroplasty (UKA) have shown a slightly higher revision rate than total knee arthroplasty (TKA), and implant fixation geometry seems to affect prosthetic survivorship. Whether metal-backed tibial component leads to superior performance over the all-polyethylene design is unclear, and a lack of evidence exists in literature. Our purpose was to demonstrate which implant design of UKA (all-polyethylene or metal-backed tibial component) is clinically superior regarding revision rates and clinical functioning, and investigate the role of potential factors that could affect the revision rate. A systematic review was conducted for clinical studies comparing all-polyethylene and metal-backed tibial components used in primary UKAs in terms of revision rates and clinical scores. Meta-regression techniques were used to explore factors modifying the observed effect. All causes of revision were extracted and analyzed, to find statistically significant differences between the two groups. Our research strategy generated a systematic review of nine studies comprising 1,101 UKAs in 1,088 patients with 87 revisions for any reason. Meta-analysis showed a higher, but not statistically significant, risk of aseptic revision in the all-polyethylene group. Studies with a smaller sample size and higher percentage of female patients were correlated to a higher relative risk of revision in favor of all-polyethylene UKAs. Differently, patients' age and duration of follow-up did not influence the risk ratio. The main cause for revision was aseptic loosening in both implants' component, with no statistically differences in the two groups examined. Our results do not show a superiority of the metal-backed tibial component in UKAs in terms of survivorship, although extreme care must be given for patients with high risk of early failure, such as female patients. However, surgical experience, in combination with careful patient selection, remains paramount and may lead to better long-term outcomes in patients requiring UKA. This is a Level III, therapeutic study.


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