Optimising Knee Therapies - Function of the Meniscus and Meniscal Interventions

In the UK, one third of people aged over 45 have sought treatment for osteoarthritis, costing the NHS over £5 billion per year. The knee is the most common site for osteoarthritis. The aging population with expectations of more active lifestyles, coupled with the increasing demand for treatment of younger patients, are challenging the current therapies for knee joint degeneration. Total knee replacement has been relatively successful in treating late stage osteoarthritis in older patients, however device survivorship in younger and more active patients is lower. There is a major unmet clinical need for effective earlier stage interventions that delay or prevent the requirement for total knee replacement surgery.
Less invasive repair and regenerative therapies for the cartilage and bone, as well as for meniscus and ligaments, have potential for large global markets (each >$1bn). Despite the clinical need and large market size, successful early-stage interventions for knee joint damage or degeneration remain elusive. For example, partial meniscectomy is commonly undertaken for damage to the meniscus, but clinical results suggest it is no more successful than a sham procedure. At present there is a lack of understanding of the tribological and biomechanical function of these interventions, which are critical if they are to perform in vivo. The limitations in pre-clinical assessment have forced new products to be advanced prematurely to animal testing, but such tests are extremely costly, represent different morphology and loading environments to human joints, and permit only limited measurement after sacrifice. There is therefore a real need for improved pre-clinical testing methods for tissue-sparing interventions that can represent the biomechanical environment in vivo, and enable the variations in that environment across the patient cohort to be simulated. Our recent research has been the first in the world to develop experimental simulation facilities for testing whole natural knee joints.

The research challenge is to extend our experimental simulation models to investigate the tribological and biomechanical function of the meniscus and meniscal interventions. Specifically to develop experimental models of porcine knees to investigate the effect of meniscus damage, extrusion and repair, and partial meniscectomy.
The model will incorporate variation of the surgical procedure and evaluate how both patient and surgical variance affects function and performance.

Aim:
To investigate the tribological and biomechanical function of the meniscus and meniscal interventions through the development of an experimental porcine model. Time permitting the model will then be extended to human cadaveric knee tissue.

Objectives:
- Develop an experimental model to investigate biomechanics of meniscus extrusion of the porcine knee
- Develop and evaluate experimental models of porcine meniscus extrusion based on meniscus attachment degeneration and meniscus attachment partial rupture
- Establish relationships between attachment changes, amount of extrusion and changes in load distribution between meniscus and articular cartilage
- Investigate effect of meniscus tears on above
- Develop a micro CT loading rig and model of extrusion
- Undertake tribological studies of meniscus extrusion model
Facilities:
Biomechanical and tribological characterisation will be carried out in the iMBE Mechanical Engineering laboratories.
There is considerable investment in the development of early interventions for tissue repair and regeneration in the natural knee, yet there is limited capability to pre-clinically simulate and evaluate the biomechanical or tribological function of regenerative interventions in the natural tibio-femoral knee joint, prior to animal studies or clinical trials.
This project will advance novel enhanced stratified pre-clinical simulation methods for regenerative interventions in the tibio-femoral knee joint.