- Elevated Plantar Pressure in Women with a History of Metatarsal Stress Fractures
- Modeling, Design, and Testing of a Joint Replacement for MTPJ1
- Joint Range-of-Motion After Orthopaedic Surgery
- Quantitative Prescription of Foot Orthoses: A Dose-Response Study of Kinematics in Patients with Foot and Ankle Pain using Biplane Fluoroscopy
- Simple Motion Capture Technology for Readiness of Return to Sport Assessment and Injury Risk Prediction
It is believed that stress fractures to the long bones of the foot (metatarsals) are caused by multiple cycles of bending during activities such as walking. In older individuals – particularly post-menopausal women who may have reduced bone mineral density - the susceptibility to stress fracture may be increased because of reduced bone cross-sectional area and bone mineral density.
Certain foot structures may further increase the risk of stress fracture. For example, if one or two metatarsal heads are taking most of the load during foot contact, these bones will experience greatly increased stresses compared to feet in which there is more load sharing.
In this study, we are recruiting women who have experienced prior metatarsal stress fracture(s) and will examine the characteristics of their feet to identify risk factors. This study will provide important information in working toward developing interventions in at-risk feet (such as customized footwear) that could prevent the occurrence of stress fractures without requiring the individuals to reduce their activity patterns.
If you are interested in taking part in this study, please get in touch with us here.
The first metatarsophalangeal joint (MTPJ1) is one of the sites most commonly affected with osteoarthritis (OA). Worldwide, more than 1 in 5 people are estimated to have pain and functional deficits from MTPJ1 OA.
In contrast to the widely performed joint replacement arthroplasties for degenerative OA at the hip and knee joints, the two most common surgical treatments for MTPJ1 osteoarthritis are cheilectomy and, for more severe cases, arthrodesis. Neither of these approaches have high rates of patient satisfaction.
To date, various designs for MTPJ1 arthroplasty have been proposed, but none have been particularly successful. This is partly because of the relatively small amount of bone in the metatarsal head and proximal phalanx, making it difficult to achieve adequate fixation of the prosthetic components, leading to loosening of the implant over time. Hemi-caps are also available for both the metatarsal head and the phalangeal base and involve the removal of less bone, however failure rates remain high.
Development of new implants that can address these problems is limited by the sparseness of the literature describing the mechanical environment of the MTPJ1, and there are no standardized open source models of the MTPJ1 available to the research community. Similarly, there is very little detailed information in the literature on the required 3D movement of the MTPJ1 during locomotor activities and what data is available is either from cadaver studies or from surface markers attached to the feet of walking subjects. It is likely that these approaches do not adequately capture the range or complexity of MTPJ1 movement due to unrealistic function and soft tissue artifacts.
In this proposal we intend to fill these voids and to generate design criteria for MTPJ1 arthroplasty by: 1) building detailed, parametric models of the MTPJ1 using OpenSim and FEBio; 2) measuring the 3D motion of the first proximal phalanx and the 1st metatarsal bones in different footwear conditions during locomotion using biplane fluoroscopy. In the final phase of the project we will combine information from these two approaches and develop prototypes for new prostheses designed to overcome some of the limitations of previous devices. Specifically, we will explore methods to utilize screw fixation, similar to locking plates. Prototypes of these designs will be 3D printed in stainless steel and tested to assess feasibility and integrity in loading experiments with cadaver feet.
We believe that the proposed work has the potential to reinvigorate the innovative study of MTPJ1 replacement, which is, at present, primarily driven by ideas not by data. To volunteer to take part in this study, please contact Dr Scott Telfer at firstname.lastname@example.org
It is widely believed that outcome evaluations of joint surgeries should include an objective assessment of patient activity, as well as self-assessment by the patient. Excessive activity following a Total Knee Arthroplasty (TKA) has been implicated in adverse outcomes, as has not enough activity following TKA. If an activity assessment is conducted, it is frequently based on the opinion of an observer or patient rather than through objective measurement.
The purpose of this study is to explore the feasibility of measuring joint range-of-motion after surgery in a home setting. The joint range-of-motion in people who have had surgery will be compared to individuals whose joints are healthy.
This project extends the reach of post-operative orthopaedic care into the home setting. We are providing a tool that will demonstrate the feasibility and value of remote monitoring during rehabilitation after orthopaedic joint surgery. Post-operative monitoring of patients is now recognized as one of the most important frontiers of care that can positively affect patient outcomes. Ensuring that patients are proceeding with their rehabilitation in an appropriate manner will be facilitated through the use of the motion-monitoring system that is being developed for this study.
To volunteer to take part in this study please contact Dr Peter Cavanagh at email@example.com
Quantitative Prescription of Foot Orthoses: A Dose-Response Study of Kinematics in Patients with Foot and Ankle Pain using Biplane Fluoroscopy
Our aim with this proposal is to better understand how in-shoe foot orthoses achieve improvements in foot and ankle function for people with ankle osteoarthritis (OA) and/or adult acquired flatfoot resulting from posterior tibial tendon dysfunction (PTTD). We also aim to be able to predict what the optimal, personalized orthotic device for each patient is.
These are common, painful, and often highly debilitating conditions, with ankle OA estimated to affect around 6% of the adult population and adult acquired flat foot around 3.3% percent of females. It has been shown that foot orthoses can be an effective conservative intervention for these conditions, and can help to postpone or negate surgery.
However, for a significant proportion of patients foot orthoses are unsuccessful, and there is evidence that this may be a result of significant inter-individual variability in joint movement and loading response to the intervention. This may be due to a number of factors, including foot bone shape, muscle strength, and/or joint range of motion. In addition, the design of foot orthoses is often inconsistent between suppliers, largely because of the manual approach that is used to design and manufacture them. A further complicating factor is that prescriptions for foot orthoses are often vaguely written.
Improving our understanding of different foot and ankle responses to variation in foot orthotic design is essential if we are to improve how these devices function at the level of the individual patient.
To measure how the individual bones of the foot move using traditional techniques is, however, very difficult. Such methods rely on skin-mounted markers that are tracked in space to determine foot and ankle kinematics. However, the size and position of the foot and ankle bones makes it impossible to measure them all of them individually. Moreover, the movement between the skin and the underlying bones, known as soft tissue artifact, introduces significant errors into the measurements. This is further complicated by the need to wear shoes for orthoses to function properly.
Our collaborators have developed a biplane fluoroscopy system that is tailored to address the unique issues of measuring foot kinematics. This system has the additional advantage of being able to measure the effects of foot orthotics in unmodified shoes.
To achieve our objective of understanding and being able to predict the effects of orthoses, our specific aims are: : To collect, via biplane fluoroscopy, kinematic data describing the effect of varying the angle of hindfoot posting in foot orthotics. These data will be obtained from 90 participants: 30 with ankle OA; 30 with symptomatic PTTD; and 30 healthy controls. : Using the data from SA1, carry out a regression analysis to identify factors obtained from biplane fluoroscopy and clinical exam that significantly influence an individual’s response (i.e., hindfoot kinematics) to the orthotic intervention. These factors include: foot type, bone geometry, static foot posture, joint axis location, range of motion, and muscle strength. : Using the data from SA1, generate a musculoskeletal model of the foot that allows detailed analysis of the muscles and ligaments controlling ankle movement. This will be developed in the OpenSim modeling platform and made freely available upon project completion.
This proposed research project will improve our understanding of how foot orthotics work and will help us to prescribe more effective devices to patients. This will benefit the large number of people in the population with ankle osteoarthritis and adult acquired flat foot.
Simple Motion Capture Technology for Readiness of Return to Sport Assessment and Injury Risk Prediction
Assessing readiness of return to sport after injuries or surgeries is common in college athletics and complicated by the pressures that athletes face in returning to sport as quickly as possible. Unfortunately, there are few objective measures that are widely used or accepted to help guide athletic trainers and physicians to determine when athletes are ready to return to sport after injury and treatment.
The goal of this study is to use simple motion capture technology (Microsoft Kinect™) to evaluate functional movement data on healthy volunteers and compare the accuracy of this technology against a gold standard motion capture system (Vicon™). Completion of this study will allow an objective, low-cost, portable, and reproducible method to evaluate functional movements in patients before and after injury or surgery.