Designing for scale: development of the ReMotion Knee for global emerging markets.

Amputees living in developing countries have a profound need for affordable and reliable lower limb prosthetic devices. The World Health Organization estimates there are approximately 30 million amputees living in low-income countries, with up to 95% lacking access to prosthetic devices. Effective prosthetics can significantly affect the lives of these amputees by increasing opportunity for employment and providing improvements to long-term health and well-being. However, current solutions are inadequate: state-of-the-art solutions from the US and Europe are cost-prohibitive, while low-cost devices have been challenged by poor quality and/or unreliable performance, and have yet to achieve large scale impact. The introduction of new devices is hampered by the lack of a cohesive prosthetics industry in low-income areas; the current network of low-cost prosthetic clinics is informal and loosely organized with significant disparities in geography, patient volume and demographics, device procurement, clinical and logistical infrastructure, and funding. At D-Rev (Design Revolution) we are creating the ReMotion Knee, which is an affordable polycentric prosthetic knee joint that performs on par with devices in more industrialized regions, like the US and Europe. As of September 2012, over 4200 amputees have been fitted with the initial version of the ReMotion Knee through a partnership with the JaipurFoot Organization, with an 79% compliance rate after 2 years. We are currently scaling production of the ReMotion Knee using centralized manufacturing and distribution to serve the existing clinics in low-income countries and increase the availability of devices for amputees without access to appropriate care. At D-Rev, we develop products that target these customers through economically-sustainable models and provide a measurable impact in the lives of the world's amputees.

Estudio del polietileno en artroplastia total de rodilla / No disponible

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Inequalities in access to knee joint replacements for people in need.

OBJECTIVES: To quantify the effects of socioeconomic deprivation and rurality on evidence of need for total knee joint replacement and the use of health services, after adjusting for age and sex. METHODS: A random stratified sample of 15 000 people aged > or =65 years taken from central age/sex registers for the geographical areas covered by the previous Sheffield and Wiltshire Health Authorities. A self completion validated questionnaire was then mailed directly to subjects to assess need for knee joint replacement surgery and whether general practice and hospital services were being used. Subjects were followed up for 18 months to evaluate access to surgery. RESULTS: The response rate was 78% after three mailings. In those aged 65 years and over (with and without comorbidity), the proportion with no comorbid factors and in need of knee replacement was 5.1%; the rate of need among subjects without comorbidity was 7.9%. There were inequalities in health and access to health related to age, sex, geography, and deprivation but not rurality. People who were more deprived had greater need. Older and deprived people were less likely to access health services. Only 6.4% of eligible people received knee replacement surgery after 18 months of follow up. CONCLUSIONS: There is an important unmet need in older people, with significant age, sex, geographical, and deprivation inequalities in levels of need and access to services. The use of waiting list numbers as a performance indicator is perverse for this procedure. There is urgent need to expand orthopaedic services and training.

Unicompartmental knee arthroplasty (alias uni-knee). An overview with nursing implications.

During the past 30 years, the unicompartmental knee arthroplasty has undergone growing pains with various implant designs, refining indications, and improving surgical techniques and instrumentation. Today, studies show survivorship results comparable to the tricompartmental total knee arthroplasty and a renewed interest has emerged. Even though the unicompartmental knee arthroplasty is recommended for only a select 10-15% who have osteoarthritis of the knee, it has many advantages over the total knee arthroplasty. Although the nursing care and rehabilitation are similar to the total knee arthroplasty, including wound care, prophylactic antibiotics, and venous thromboembolism prophylaxis, the patient frequently has less pain, increased range of motion, shorter hospitalization, and fewer complications, resulting in a quicker rehabilitation.

Effect of femoral component designs on the contact and tracking characteristics of the unresurfaced patella in total knee arthroplasty.

OBJECTIVES: To determine the effect of 5 different femoral components used in total knee arthroplasty (TKA) on the contact area and tracking characteristics of the nonresurfaced patella and to identify any design features that might adversely affect these characteristics. DESIGN: An in-vitro study. SETTING: The biomechanics laboratory, Department of Mechanical Engineering, McGill University, Montreal. SPECIMENS: Six fresh-frozen cadaveric knee-joint specimens. INTERVENTIONS: An unconstrained quadriceps simulator was used to apply the conditions of static lifting to the specimens first in their normal state and then sequentially implanted with femoral and tibial components of various designs (Miller/Galante II, Anatomic Modular Knee [AMK] System, Whiteside Ortholoc Modular, press-fit condylar and Insall-Burstein II). OUTCOME MEASURES: Patellar 3-dimensional tracking characteristics, determined by using a 6 degrees-of-freedom electromechanical goniometer attached directly to the patella, and patellar contact pressure measurements, obtained using low-range Fuji Prescale film. RESULTS: Articulation of the normal patella on a prosthetic femoral component resulted in alterations in the normal patellofemoral contact and tracking characteristics. The exact departure depended on the design of the prosthetic trochlea. Although all of the selected prostheses demonstrated satisfactory contact characteristics near extension, marked alterations occurred at higher flexion angles. With 90 degrees or more of flexion, there was incompatibility between the geometries of the prosthetic notch of 2 femoral designs (AMK and PFC) and the normal knee. CONCLUSION: The design of the prosthetic femoral component must be taken into account when determining whether or not to resurface the patella at the time of TKA.

Patient demand matching in total knee arthroplasty: is it necessary?

Patient demand matching has been accepted as an appropriate method of implant management by hospitals for cost reduction. However, there have been no prospective studies to substantiate whether these patients change their demand levels postoperatively. Theoretically, functional activity levels should not increase significantly postoperatively in patients with preoperative low demand levels for patient demand matching to be effective in avoiding premature prosthetic failure. Preoperative and postoperative demand levels were prospectively reviewed in 279 patients undergoing total knee arthroplasty (TKA). Preoperatively, the medium/high-demand patients performed significantly more activities overall than low-demand patients. Postoperatively, both low- and medium/high-demand patients dramatically increased the number of activities performed. The hypothesis that prosthetic choice should be determined by preoperative activity level (demand matching) was not validated by this study because patient activity levels significantly increased in all categories subsequent to TKA.