scholarly journals The Medial Eminence Line for Predicting Tibial Fracture Risk after Unicompartmental Knee Arthroplasty

2020 ◽  
Vol 12 (2) ◽  
pp. 166 ◽  
Author(s):  
Ryo Yoshikawa ◽  
Takafumi Hiranaka ◽  
Koji Okamoto ◽  
Takaaki Fujishiro ◽  
Yuichi Hida ◽  
...  
2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Elvis Chun-sing Chui ◽  
Lawrence Chun-man Lau ◽  
Carson Ka-bon Kwok ◽  
Jonathan Patrick Ng ◽  
Yuk-wah Hung ◽  
...  

Abstract Background Periprosthetic fracture of the tibia after unicompartmental knee arthroplasty has been reported to be associated with excessive pin holes created for stabilization of the cutting guide. However, fractures have also been reported in cases using two pins as in the method suggested by the manufacturer. It is currently unclear whether variations in pinhole positions make a difference in proximal tibial fracture risk. Methods Finite element models were constructed using Chinese female bone computed tomography images, with bone cuts made according to the surgical steps of implanting a fixed bearing unicompartmental arthroplasty. Four combinations of pinholes (pins placed more closely to the medial tibial cortex or centrally along the mechanical axis as allowed by the tibial cutting guide) created for tibial cutting guide placement were tested by finite element analyses. Testing loads were applied for simulating standing postures. The maximum von Mises stress on the tibial plateau was evaluated. Results Pinhole placed close to the medial edge of the proximal tibial plateau is associated with the highest stress (27.67 Mpa) and is more likely to result in medial tibial fracture. On the contrary, pinhole placed along the central axis near the tibial tuberosity has the lowest stress (1.71 Mpa) and reflects lower risk of fracture. Conclusion The present study revealed that placing tibial cutting guide holding pins centrally would lower the risks of periprosthetic fracture of the medial tibial plateau by analyzing the associated stress in various pin hole positions using finite element analysis.


Author(s):  
D. M. Moore ◽  
G. A. Sheridan ◽  
A. Welch-Phillips ◽  
J. M. O’Byrne ◽  
P. Kenny

Abstract Purpose Unicompartmental knee arthroplasty (UKA) provides patients with an alternative treatment to TKA in isolated medial compartment osteoarthritis providing better functional outcomes and faster recovery in the short term. Our aim was to quantify revision rates, predictors of revision, mortality rate and functionality of the Oxford Phase 3 UKA in a non-designer institution. Methods This was a retrospective review of prospectively collected regional registry data. All Oxford Phase 3 UKAs performed for medial tibio-femoral osteoarthritis of the knee joint were included from a single academic institution between the period of January 1st 2006 and December 30th 2009. Kaplan-Meier survivorship curves adjusting for loss to follow-up and deceased patients were generated. Primary outcome variables included all-cause and aseptic revision. Secondary outcome variables included functional outcome scores. Patients were reviewed at 6 months, 2 years, 5 years, 10 years and 15 years. Results A total of 64 cemented Oxford phase 3 UKAs were performed between January 2006 and November 2009. Fifteen-year follow-up data were available for 51 patients, of these 12 required revision. Survival rates, adjusting for patients that were either lost to follow-up or deceased, were 87.5% at 5 years, 81.4% at 10 years and 76.4% at 15 years. The overall aseptic revision rate at the time of review was 18.75% (n = 12). The only significant predictor of postoperative WOMAC score at 15 years was the preoperative WOMAC score (p = 0.03). Conclusion The Oxford Phase 3 UKA for medial tibio-femoral arthritis has promising outcomes at 15-year follow-up with a survival rate of 76.4% in a non-designer centre. Level of Evidence III.


Sign in / Sign up

Export Citation Format

Share Document