Knees

Allegra Orthopaedics’ principal product, the Active Knee, is a primary total knee replacement prosthesis. It consists of both cementless & cemented options, with 18 femur sizes and 10 tibia sizes to suit a wide patient population. Meniscal inserts are available which allow the surgeon to retain or sacrifice the posterior cruciate ligament. The femoral and tibial components are manufactured from CoCrMo (ASTM F75 / ISO 5832-4) whilst the Meniscal Insert is manufactured from UHMWPE (ISO 5834-1, ISO 5834-2 and ASTM F648) The Active Knee design features include:

• unique, exclusive surface finishing (Ultrapolishing) that imparts wear characteristics approaching that of ceramics;
• cementless design with a sintered hydroxyapatite coating that encourages rapid bone bonding with the implant. For patients that are unsuited to a cementless implant, a cemented version is also produced;
• a cruciate retaining design that, for a total knee, minimises the invasiveness of the operation and patient trauma.

The Allegra Active Knee has an excellent patient success rate. A journal article published in 2005 by the Journal of Bone and Joint Surgery (UK), prospectively reviewed 1000 patients with up to 10 year outcomes, reported excellent patient functional results and an extremely low incidence of revisions (complications). Importantly, the Allegra Active Knee has a clinical history extending over 20 years, demonstrating excellent patient outcomes & therefore considered a thoroughly proven design. The Allegra Active Knee has a growing number of supportive published academic papers as well as thousands of knees implanted worldwide. Product Options And Features Include:

• FDA-approved, CE-marked cemented versions
• Cementless versions with hydroxyapatite and porous in-growth surfaces – CE Marked
• Narrow femoral versions – the World’s First “Female Knee’ – implanted since 2001.
• Ultra-polished surfaces

Allegra has developed new instrumentation, with the following benefits for users:

1. Two options for femoral implantation – distal first or anterior.
2. Newer instruments – ability to cut tibia or femur first.
3. Variable and changeable external rotation guide from internal rotation in one degree increments to six degrees external.
4. Referencing to ensure the femur is bone sparing.
5. Five-in-One femoral cutting blocks, which are shaped like the femur – ensures the user can appreciate the shape and position of trochlear, the width of the femur, and rotation, all before any cuts are made. Allows the user to fully explore all 10 femoral sizes.
6. Tibial guide that is
   • low profile, allowing for minimally invasive surgery and fat pad preservation.
   • thin enough to ensure the saw blade will always cut the tibia without needing to remove the jig and finish off the cuts.
7. Varus and valgus recut guides that are intuitive.
8. Tibial preparation tools for cementing, which don’t impact or damage the femoral cuts.

The high modularity of the MEGASYSTEM-C^® allows partial bone replacements both in the proximal and distal femur in small increments as well as a total replacement of the femur. For knee joint replacement, implants of the knee joint system Endo-Model^® and Endo-Model^® SL^® are integrated into the MEGASYSTEM-C^®.

Features:

• Compatible with standard implant systems (MP^® Hip Revision System and Endo-Model^® knee joint components)
• Modularity of the system makes it possible to react flexibly to intraoperative situations
• Cementable and cementless anchoring stems
• Leg length adjustment in 10 mm increments
• Microporous Implant surfaces support bone ongrowth

Rotational and hinge knee prosthesis for primary and revision surgery Used as primary prosthesis or as revision treatment, as a rotational or hinge knee, with the Endo-Model^® rotational knee prosthesis there are many options available.
Features:

• Minor bone resection with primary implantation
• Natural gait through physiological pivot and axial rotation
• For greater bone substance loss, ligament instabilities and extreme muscular insufficiency

Modular knee prosthesis for primary and revision surgery The modular intracondylar total knee prosthesis Endo-Model^® – M. The modular prosthesis stems are available in two versions for cemented or cementless implantations, in varying lengths.

Features:

• Hinge joint or rotational knee joint with mounted pivot within the physiological area
• Stable position during extension
• Constructively generated, elastic rotational force transmission (overrun brake) for preservation of the anchorage
• Favourable dimensions for bone preservation: only 14 mm resection at the tibia-femur joint level
• Available in lengths of 50 to 280 mm.

The kinematics and anchoring principles of the rotational and hinge knee are based on the Endo-Model^® solution for the fixed-hinge knee replacement, which has been successfully proven for decades.

Features:

• Intraoperative choice between rotational and hinge mechanism
• Compatible with component of the MEGASYSTEM-C^®

In conjunction with the minimally invasive surgical technique MITUS^®, this surface replacement is particularly bone-sparing and gentle on soft tissue.

Features:

• Optimal implant/cement bonding through a globular macrostructure on the undersides of the prostheses
• Tibial plateaus from UHMWPE with and without metal backing
• Minimally invasive or conventional implantation technique possible