Proceedings ArticleDOI
Knee laxity after unicompartmental joint replacement: A planar mathematical analysis
Ahmed Imran
- pp 424-427
TLDR
A sagittal plane mathematical model of the knee with unicompartmental replacement is used to analyze the passive antero-posterior laxity during flexion and suggests that the UKR requires close attention to component placement.Abstract:
Passive knee laxity is an important clinical measure to assess function after joint replacement. Clinical observations suggest that the use of minimally invasive surgical techniques in knee arthroplasty may affect the surgeon's ability to orient and position the prosthetic components accurately. Further, recent studies suggest that malplaced prosthetic components in unicompartmental knee replacement (UKR) can affect the ligament forces and, hence, the knee laxity. In the present study, a sagittal plane mathematical model of the knee with unicompartmental replacement is used to analyze the passive antero-posterior (A-P) laxity during flexion using different force levels. Also, the effects of errors in component position are evaluated. The results show that for all force levels, the A-P laxity first increases from 0° to about 30° flexion, remains nearly constant for another 10° and then decreases somewhat linearly for higher flexion angles. Changes in the position of the femoral component by 1mm can affect the knee laxity by 2mm or more in some flexion positions. The analysis has clinical relevance and suggests that the UKR requires close attention to component placement.read more
Citations
More filters
Proceedings ArticleDOI
A Force Line Trajectory Measuring System and Algorithms for Unicondylar Knee Replacement Surgery
Zhe Su,Zhihua Wang,Hong Chen +2 more
TL;DR: An UKA force line trajectory measurement system, which includes the pressure sensors array, the controlling circuits, the transceivers, and the receiving recorder, which meets the requirement of real-time display force line trajectories and the calculation amount is significantly reduced compared to the finite element analysis method.
Passive Anterior-Posterior Knee Stability After Unconstrained Unicompartmental Arthroplasty
TL;DR: A mathematical model of the knee with unconstrained unicompartmental arthroplasty was used to study relative translations of the bones during a simulated A-P laxity test and agreed in general with the experimental measurements showing similar patterns during flexion.
References
More filters
Journal ArticleDOI
The Mechanics of the Knee and Prosthesis Design
John Goodfellow,John J. O'Connor +1 more
TL;DR: Some principles which might guide the design of knee prostheses are deduced and it is shown that current designs transgress some of these principles.
Journal ArticleDOI
The role of joint load in knee stability.
TL;DR: Fresh cadaver knees were tested at full extension and at 20 degrees of fiexion in specially designed fixtures that allowed tibiofemoral contact forces to be applied to the knee while movement of the joint was not restricted.
Journal ArticleDOI
Rapid recovery after oxford unicompartmental arthroplasty through a short incision.
TL;DR: Accuracy of implantation, assessed from 11 variables seen on fluoroscopically centered postoperative radiographs, was the same after UCA by the short-incision approach as after the open approach, suggesting that theshort-term advantage of increased speed of recovery was gained without affecting the long-term results.