Journal ArticleDOI
Sagittal plane knee laxity after ligament retaining unconstrained arthroplasty: a mathematical analysis
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TLDR
A sagittal plane mathematical model of the knee with intact ligaments and unconstrained prosthetic components is used to analyze antero-posterior (A–P) knee laxity during passive flexion at different force levels and suggests that the UKA 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 ligament retaining unconstrained unicompartmental knee arthroplasty (UKA) can affect the ligament forces and, hence, the knee laxity. In the present study, a sagittal plane mathematical model of the knee with intact ligaments and unconstrained prosthetic components is used to analyze antero-posterior (A–P) knee laxity during passive flexion at different force levels. Also, the effects of errors in component placement are evaluated. The model calculations show a reasonable agreement with the experimental observations reported in literature. The results show that the A–P laxity during 0°–120° flexion first increases from 0° to about 30°, remains nearly constant for another 10° and then decreases somewhat linearly for higher flexion angles. Some errors in the placement of femoral component of the order of 1 mm can affect the knee laxity by nearly 3 mm in some flexion positions. The analysis has clinical relevance and suggests that the UKA requires close attention to component placement.read more
Citations
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Book ChapterDOI
Computer Graphics Based Approach as an Aid to Analyze Mechanics of the Replaced Knee
TL;DR: A planar mathematical model of the human knee is used for analyzing the mechanics of the joint after replacement with artificial implants using computer programming, motion and force data is generated for a large number of joint positions, which is used to simulate the knee mechanics during flexion/extension.
Book ChapterDOI
Computer Graphics Based Analysis of Loading Patterns in the Anterior Cruciate Ligament of the Human Knee
TL;DR: A computer-based model of the knee with intact ligaments and anatomical articular surfaces was used to visualize contributions of different fiber bundles in the ligament with distinct areas of attachment on the femoral bone that are searched for appropriate positions of femoral tunnel during single or double bundle ligament reconstruction.
Book ChapterDOI
Computer Graphics-Based Analysis of Anterior Cruciate Ligament in a Partially Replaced Knee.
TL;DR: Artificial human knee with partial prosthetic replacement was modelled in the sagittal plane in order to analyze the role of anterior cruciate ligament in an unconstrained artificial knee and helped in visual analysis and in gaining insight into the joint behavior with clinical relevance.
Book ChapterDOI
Estimates of Cruciate Ligament Forces Resulting from Anterior Tibial Translation During Simulated Flexion Motion of the Human Knee
TL;DR: In this article , a mathematical model is used to simulate such laxity tests and estimate cruciate ligament forces when the lower leg at the knee is translated anterior to thigh, thus, stretching the anterior cruciato ligament.
References
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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.
Journal ArticleDOI
Clinical results of the Oxford knee. Surface arthroplasty of the tibiofemoral joint with a meniscal bearing prosthesis.
John Goodfellow,John O'Connor +1 more
TL;DR: The Oxford method of knee arthroplasty is proposed as a reliable and safe alternative to more invasive prostheses in rheumatoid and osteoarthritic joints in which the disease is still limited to the articular surfaces.
Journal ArticleDOI
The geometry of the knee in the sagittal plane.
TL;DR: A geometric simulation of the tibio-femoral joint in the sagittal plane is developed which illustrates the central role played by the cruciate ligaments in the kinematics of the knee and which can be used for the analysis of ligament and contact forces.