Jessica M. Fritz

Recent developments in osteogenesis imperfecta

Osteogenesis imperfecta (OI) is an uncommon genetic bone disease associated with brittle bones and fractures in children and adults. Although OI is most commonly associated with mutations of the genes for type I collagen, many other genes (some associated with type I collagen processing) have now been identified. The genetics of OI and advances in our understanding of the biomechanical properties of OI bone are reviewed in this article. Treatment includes physiotherapy, fall prevention, and sometimes orthopedic procedures. In this brief review, we will also discuss current understanding of pharmacologic therapies for treatment of OI.

Biomechanical model to assess injury reduction during impact

This paper implements a biomechanical model and actual tipover trajectory data to assess the risk of head and neck injuries in standup forklift accidents. Seven accident scenarios were analyzed for right tipover, left tipover and off-dock accidents both with and without a door on the operator compartment. Each model had specific data including human anthropometry and trajectory input into the modeling and analysis software packages, Visual-Safe MAD and MADYMO. For all three accident scenarios, each of the seven biomechanical models was analyzed for Injury Assessment Reference Values (IARVs) including angular velocity (omega, ω), angular acceleration (alpha, a), Head Injury Criterion (HIC), Neck Injury Criterion - shear, tension and bending (NIC) and the biomechanical Neck Injury Predictor (Ny). The study concluded that, in general, the addition of a door to the standup forklift operator compartment leads to a reduction in injury during tipover and off-dock accidents. The ability to brace for impact is not included in these MADYMO models. Bracing is far more effective with an enclosed compartment provided by a latching rear door.

Amputee Subject Testing Protocol, Results, and Analysis of a Powered Transtibial Prosthetic Device

A powered ankle-foot prothesis and its control system were previously designed and built. To evaluate this prosthesis, amputee subject testing was performed. The testing results are analyzed and compared between the powered prosthesis, passive prosthesis, and able-bodied gait. Qualitative comparison showed the prosthesis achieved the design objectives. During stance phase, active ankle moment was generated in the powered prosthesis before push-off to help the amputee walk more naturally. During swing phase, the powered prosthesis was able to move to natural position to achieve foot clearance. However, the prosthesis is slightly under powered compared with the able-bodied ankle.

Distribution of segmental foot kinematics in patients with degenerative joint disease of the ankle: SEGMENTAL KINEMATICS IN ANKLE ARTHRITIS

Degenerative joint disease (DJD) of the ankle is a debilitating chronic disease associated with severe pain and dysfunction resulting in antalgic gait alteration. Little information is available about segmental foot and ankle motion distribution during gait in ankle osteoarthritis. The aim of the current study was to dynamically characterize segmental foot and ankle kinematics of patients with severe ankle arthrosis requiring total ankle replacement. This was a prospective study involving 36 (19 M, 17 F) adult patients with a clinical diagnosis of ankle arthrosis (“DJD” group) and 36 (23 M, 13 F) healthy subjects (“Control” group). Motion data were collected at 120 Hz using a 3‐D motion camera system at self‐selected speed along a 6‐m walkway and processed using the Milwaukee Foot Model (MFM). The SF‐36 Health Survey and Orthopaedic Foot and Ankle Society (AOFAS) ankle‐hindfoot scale were administered to evaluate functional levels. Findings include decreases in walking speed, cadence, stride length and swing phase, and reduced outcomes scores (SF‐36 and AOFAS). Multisegemental motion in patients with ankle DJD demonstrates significant changes in foot mechanics characterized by altered segment kinematics and significant reduction in dynamic ROM at the tibia, hindfoot, forefoot, and hallux when compared to controls. The results demonstrate decreased temporal‐spatial parameters and low outcomes scores indicative of functional limitations. Statement of clinical significance: Altered segment kinematics and reduced overall range of motion demonstrate how a single joint pathology affects kinematic distribution in the other segments of the foot and ankle and alters patients’ overall gait.

Assessment of Kinematics and Electromyography Following Arthroscopic Single-Tendon Rotator Cuff Repair

The increasing demand for rotator cuff (RC) repair patients to return to work as soon as they are physically able has led to exploration of when this is feasible. Current guidelines from our orthopedic surgery clinic recommend a return to work at 9 weeks postoperation. To more fully define capacity to return to work, the current study was conducted using a unique series of quantitative tools. To date, no study has combined 3‐dimensional (3D) motion analysis with electromyography (EMG) assessment during activities of daily living (ADLs), including desk tasks, and commonly prescribed rehabilitation exercise.

Sagittal Subtalar and Talocrural Joint Assessment During Ambulation With Controlled Ankle Movement (CAM) Boots

Background: The purpose of the current study was to determine sagittal plane talocrural and subtalar kinematic differences between barefoot and controlled ankle movement (CAM) boot walking. This study used fluoroscopic images to determine talar motion relative to tibia and calcaneal motion relative to talus. Methods: Fourteen male subjects (mean age 24.1 ± 3.5 years) screened for normal gait were tested. A fluoroscopy unit was used to collect images at 200 Hz during stance. Sagittal motion of the talocrural and subtalar joints were analyzed barefoot and within short and tall CAM boots. Results: Barefoot talocrural mean maximum plantar and dorsiflexion were 9.2 ± 5.4 degrees and −7.5 ± 7.4 degrees, respectively; short CAM boot mean maximum plantar and dorsiflexion were 3.2 ± 4.0 degrees and −4.8 ± 10.2 degrees, respectively; and tall CAM boot mean maximum plantar and dorsiflexion were −0.2 ± 3.5 degrees and −2.4 ± 5.1 degrees, respectively. Talocrural mean range of motion (ROM) decreased from barefoot (16.7 ± 5.1 degrees) to short CAM boot (8.0 ± 4.9 degrees) to tall CAM boot (2.2 ± 2.5 degrees). Subtalar mean maximum plantarflexion angles were 5.3 ± 5.6 degrees for barefoot walking, 4.1 ± 5.9 degrees for short CAM boot walking, and 3.0 ± 4.7 degrees for tall CAM boot walking. Mean minimum subtalar plantarflexion angles were 0.7 ± 3.2 degrees for barefoot walking, 0.7 ± 2.9 degrees for short CAM boot walking, and 0.1 ± 4.8 degrees for tall CAM boot walking. Subtalar mean ROM decreased from barefoot (4.6 ± 3.9 degrees) to short CAM boot (3.4 ± 3.8 degrees) to tall CAM boot (2.9 ± 2.6 degrees). Conclusion: Tall and short CAM boot intervention was shown to limit both talocrural and subtalar motion in the sagittal plane during ambulation. The greatest reductions were seen with the tall CAM boot, which limited talocrural motion by 86.8% and subtalar motion by 37.0% compared to barefoot. Short CAM boot intervention reduced talocrural motion by 52.1% and subtalar motion by 26.1% compared to barefoot. Clinical Relevance: Both short and tall CAM boots reduced talocrural and subtalar motion during gait. The short CAM boot was more convenient to use, whereas the tall CAM boot more effectively reduced motion. In treatments requiring greater immobilization of the talocrural and subtalar joints, the tall CAM boot should be considered.

TRID Cranial Analysis During Rear Impact Simulation With MADYMO

Early studies of cranial kinematics were primarily limited to sagittal plane assessments of motion secondary to impact in volunteers, models, anthropometric dummies and human specimens [1]. With advances in instrumentation and imaging technology, more relevant studies of three dimensional (3-D) motion began to emerge. More complex 3-D head kinematics were first quantified with arrays of precisely positioned multi-axis accelerometers [1]. This evolution in quantitative ability has continued to the present time with the application of high speed motion capture systems and more sophisticated mathematical models.Copyright