Background

 MMATECH developed a novel advanced, tough, low-friction, biocompatible, wear and cold flow resistant polyimide MP-1™, for medical implants that will revolutionize the multi-billion dollar orthopedic markets. The MP-1™ acetabular liner is 3 times more durable than current materials.

MMATECH Milestones

• 2005 -First-proof of MP-1™ biomaterial as potential platform for medical applications

• 2006 –first in man Hip MP-1™ liner implant (Custom made) – 12Y follow up
• 2011- CE MARK and ISO 13485 approval
• 2012 – MMATECH becomes a medical device company. Agreement with orthopedic Company
• 2013-today – 74 patients were implanted with MP1™ liner in the first post marketing clinical study in New Zealand medical center. Technological proof-of-concept and efficacy of the MP-1™ implant have been successfully established.
• 2017 – New groundbreaking trauma device is being developed, new IP covering the invention received an EU grant

Orthopedic implantation is possibly the greatest advance in the past century. The concept of introducing an artificial joint was impossible until new materials and fixation methods were developed. These were applied by successful collaboration of materials scientists, engineers and surgeons. A joint replacement has the great advantage of providing pain free movement for injured or aging patients.

Plastics hold an important role in the field of medicine as structural materials implanted in the body and as surgical aids. Polymeric materials are advantageous compared to metals and ceramics due to their low weight, high mechanical strength (on a strength-to-weight basis), chemical stability and are non-corrosive.

Plastic materials are also easily shaped and machined and commercially available in diverse forms and structures.

Total hip prosthesis implanted currently consists mostly of hard metal on metal, or ceramic femoral head on ultra-high-molecular weight-polyethylene (UHMWPE) acetabular cup with or without cement fixation. Currently around 900,000 artificial hips are implanted in USA and Europe per year. The low-friction, low-wear UHMWPE was considered for the last two decades as the best solution for total artificial hip implants. Despite the success, over the last 10 years these prostheses showed frequent failures due to late aseptic loosening, migration, and inflammation resulting in revision surgeries. No implant survived more than 17 years, while most of the implants lasted only between 10 to 15 years. The increased need to implant hip prosthesis in younger, more active patients due to car accidents or sport injuries, requires new artificial hip joints using alternative more advanced materials and designs. The research for extending lifetime of artificial implants became the major issue within the orthopedic community.

The material chosen for an implant should endure the different loads (tensile, compression and shear) and resist friction and wear of the articulating joints.

UHMWPE(3-5) -promotes bone lysis (Periprosthetic Osteolysis) due to release of tiny sub-microns size debris into the human cells and surrounding soft tissues of the implant as a result of wear. The body reacts by releasing agents (macrophages) that attack the bone implant interface causing loosening and infection. The UHMWPE implant degrades in the body, chips off, exposing the base metal and releasing from the cemented fixation. There are 20-30 % failure cases within 5-7 years of implantation.

UHMWPE -Crosslinked(2) – shows 50% less wear than UHMWPE ,thus longer term of stability, but still has a risk of wear debris stimulated osteolysis. There is a risk of oxidation of the UHMWPE by the Gamma radiation during the cross-linking process releasing free radicals. This oxidation weakens the material and causes embrittlement during aging.

CERAMIC implants(6) are composed of Alumina and Zirconia and are mostly used in Europe. Ceramic has excellent biocompatibility (highly oxidized), good lubrication, friction and low wear, high hardness, and smooth surface finish. The drawbacks of ceramic implants are low fracture toughness and brittleness causing fragmentation, wear scars and catastrophic failure of the implant into small fragments. Failures include femoral head fractures and ceramic liners. Improved performance depends on careful operation techniques with correct positioning of the prosthesis. Massive wear and osteolysis occur between the femoral neck and the rim of the acetabular cup. Small sharp edged granular debris (0.4 µm and less) appeared in macrophages near the surface of the implant. Zirconia wear debris are more frequent than alumina. Osteolysis appeares after a mean implantation time of 92 months. Loosening and migration of acetabular fragments demanded revision surgery. Other disadvantages of ceramics are the high specific density (causing elevated weight of the implant), water hydrolysis causing crack formation in wet environment and high cost. At present, the ceramic implant occupy only 10-18% of the implant market.

Metal implants(5-7) consist today mostly of CoCrMo alloy which exhibits low wear (40-100 times lower than UHMWPE), good surface finish and high mechanical properties. The drawbacks of metals are metallic electrochemical corrosion risk (biocompatibility issue) caused by the salty body fluids and oxygen environment, formation of chemically active degradation products, and production of wear particles. The wear particles are very small (mostly 10-25 nm) but the numbers of particles exceed those of UHMWPE (13 to 500 times more). The small size and large number of the particles raise a new issue of remote distribution in the human body and biologically effectiveness on various cells and tissues. Some particles may corrode or dissolve in the lymphatic vessels. The hematological spread of the metal particles may access any tissue in the body even the brain. Metal debris in the lymph nodes cause structural changes including necrosis and fibrosis. There is an increased risk for development of tumors of the lymphatic system (carcinogenic potential). Hypersensitivity of the body to metal ions released is another problem since metal ions may bind to body proteins inducing T lymphocyte response. Another problem is the toxicity of the metal ions (Co and Cr) reducing cell viability even at low concentrations, These ions are toxic to osteoblast cells by inhibiting their differentiation. Compared to UHMWPE metal prosthesis have elevated weight. Titanium is a much lighter metal but is a poor bearing material. It wears fourfold more than CoCr and in some cases toxic. It activates macrophages and causes osteolysis. The level of inflammation depends on the amount, size and shape of the debris.

The solution: MP-1™ biomaterial:

MP-1™, a high performance polymer originating as a spin-off from Jet engine ball bearings, exhibits a superior combination of strength, toughness, wear, creep and fatigue resistance, and excellent biocompatibility, which makes it suitable for medical device applications.

MP-1™ was first designed to replace the acetabular liner of the Total Hip Replacement (THR) implant.

MP-1™ is processed by conventional techniques of compression molding allowing a broad design and manufacture flexibility, resulting in cost effectiveness.