The M.A.S.® socket design is an evolution--and perhaps even a "revolution"--in the development of ischial containment (IC) socket concepts. Since 1999, when Marlo Ortiz Vazquez del Mercado, Ortiz Internacional, Jalisco, Mexico, first unveiled his new design, it has continued to arouse interest throughout the O&P worldwide community. Recently the design was featured in the Thranhardt lecture series during the American Academy of Orthotists & Prosthetists 2004 Annual Meeting and Scientific Symposium.

The new design provides several clinical benefits: patients can sit more comfortably; there is no plastic beneath the gluteus; the prosthesis is easier to don; patients enjoy full range of motion, better functional gait--and important to patients and family members too--much better cosmesis. Seeing a video of patients walking, sitting, and demonstrating the range of motion possible is truly amazing.

What is the M.A.S. Socket

Ortiz describes his design: "It is very important to consider the angle of the ischial ramus. The ischial tuberosity and part of the ramus as well as the medial aspect of the ramus are encapsulated within the medial aspect of the socket brim." Generally, the medial wall is lowered anteriorly to avoid pressure on the ascending ramus; effectively ischioramal weight-bearing eliminates the need for gluteal support, so those tissues can be excluded from the socket, he explained.

In the conventional design, posterior trim lines include part of the gluteus maximus. In the M.A.S. design, the height of the posterior wall has been lowered to the gluteal fold, so the entire muscle belly can be free of the socket. "This will not only improve cosmesis but with this configuration, we have found that ischial tuberosity and part of the ischial ramus are encapsulated more effectively with no restriction in hip movement," Ortiz said.

The Harmony® system effectively reduces the amount of air between the socket and the liner. This is achieved through the use of a pump and an exhaust valve. The system, which is activated at every step when using the mechanical pump or by a sensor with the electronic version, regulates the required negative pressure within a defined range.

A damping and torsion function is also integrated into the mechanical pump. The Harmony® system controls the volume of the residual limb and simultaneously improves blood circulation. High adhesion improves proprioception. The prosthesis wearer feels what is happening under his or her prosthetic foot. This increases safety in everyday life. The Harmony® system is used in conjunction with a polyurethane liner. A standard or custom liner is used depending on the residual limb. The negative pressure system is sealed on the outside by means of a gel-coated sealing sleeve.

www.ossur.com The newly redesigned RHEO KNEE® is an advanced prosthetic device that liberates its users to focus on their chosen activity, instead of having to think about how they are walking. New developments in Össur's proven bionic technology mean that the RHEO KNEE can recognize and respond even better to the most subtle changes in walking speed and terrain. Using sophisticated artificial intelligence, it continuously learns and adapts to an amputee's walking style and environment. As a result, it restores people's ability to walk naturally, comfortably and confidently at any speed. The RHEO KNEE is now available with a female pyramid insert or a Threaded Top adapter ideal for knee disarticulation amputees, those with long transfemoral residual limb or where the low build height is required. Product Highlights: Strong design - now for use by people weighing up to 275lbs / 125kg. Light weight and streamlined, anatomical shape - for easy cosmetic covering. Extremely smooth swing extension - for natural, confident, energy-efficient gait. Optimum stance support - for unparalleled safety, even for less agile, heavier or compromised users. Plug and play design - for fully automated set up and continuous adaptation, ensuring a straightforward experience for CPOs and users alike (includes Bluetooth wireless communication between the knee and PDA). Thanks to its limited build height, the RHEO KNEE is fully compatible with the Flex-Foot range. Together they deliver maximum performance and an extraordinarily natural gait experience. Available with a threaded top adapter where low build height is required.