1) What is the press-fit of the Lima Modular Revision Hip (LMRH)?
The LMRH does not use a typical cementless stem measure of press-fit. Instead, the stem utilizes cortical engagement to achieve primary fixation. The fins of the stem circumferentially cut into the cortical bone to achieve primary fixation. For the LMRH, 1mm of fin engages the cortical wall on both sides of the hip for a total of 2mm of cortical engagement. The laminated product reference card provides specific information on the implant versus the last reamer used.
2) What is the recommended last reamer versus the implant?
2mm smaller than the final planned stem implant. For instance, if a size 16 stem is implanted, the final recommended reamer is a 14mm.
3) What material is used in the construction of the LMRH?
The proximal bodies and stems are made of Ti6Al4V, titanium alloy. There is a small anti-rotation peg found in the proximal body locking screw made of UHMWPE. The acetabular reconstruction cages are made of commercially pure titanium
4) What is the fin height on the LMRH?
The fin height depends on the size of stem. For stem sizes 14 and 16 the fins are 1mm in height for both the 140mm and 200mm stem. For stem sizes 18-24mm for both the 140mm and 200mm stems the fin height is 1.5mm.
5) How long has this implant been implanted?
The stem has been implanted in the European market since 1996.
6) What is the taper of the implant stem?
The stem has a 1.6 degree taper angle.
7) What is the range of stem diameters?
The distal stem is available in six sizes from 14 to 24mm stem diameters (every two mm).
8) What is the range of the proximal bodies?
The proximal bodies are available in seven sizes from 50 to 110mm (every ten mm).
9) What is the neck angle of the LMRH?
The standard proximal body has a neck angle of 131 degrees while the offset body has a neck angle of 135 degrees. This is assuming the stem taper is positioned at a neutral position. By varying the stem taper position, a range of neck angles, ranging from 127 degrees to 139 degrees may be achieved.
10) What is the surface finish of the LMRH?
The proximal body and distal stem have a grit-blasted surface finish that has an Ra of 3 to 4 um. The proximal body also has a highly polished neck to help minimize polyethylene debris from impingement.
11) What is the range of implant lengths that can be constructed with the LMRH?
190mm to 310mm
12) What is the height of the stem taper?
30.5mm
13) Why is there a 4 degree tilt to the distal stem taper?
The 4 degree taper angle of the Lima Modular Revision Hip provides additional options for proximal implant positioning with the flexibility of a straight stem. The fluted distal stem can be placed in any 360 degree rotational position for the best reconstruction of the patient's anatomy. The proximal taper angle can be rotated to the anterior/posterior planes to recreate the femur's natural anterior bow or rotated to the medial/lateral planes to provide offset or to recreate the original femoral anatomy of a varus or valgus neck.
14) Is the LMRH taper compatible with DJO Surgical's current femoral head options?
The LMRH is fully compatible with DJO Surgical's full range of acetabular options. These include revision, jumbo, FMP™ multi-hole shells, X-alt™ highly crosslinked polyethylene with offset revision configurations, large diameter BIOLOX® delta ceramic heads, metal on metal and ceramic on ceramic bearing options.
15) What is a Wagner-type stem?
Wagner type hip: [VAHG-nur] is a tapered, fluted, grit-blasted, titanium alloy, revision hip design developed in the 1990s by German orthopedic surgeon Heinz Wagner, MD.
These stems feature a cylindrical, tapered distal portion with longitudinal straight fins for cortical fixation and rotational stability; the original Wagner stem made by Zimmer (Wagner SL) is a one-piece design; many modular revision hips are marketed with Wagner-type distal components.
16) What are the competitive stems to the LMRH?
Wagner SL and ZMR from Zimmer, Restoration from Stryker, Mallory-Head Modular from Biomet, Link MP and Profemur R from Wright Medical are all direct competitors to the LMRH.
17) Is there a gap between the final proximal body and the distal stem?
Yes, there is a 2 to 3mm gap between the proximal body and distal stem when the implant is fully assembled. This is completely normal.
18) How do I know how much to tighten the proximal body to the distal stem?
The taper is held in place with the proximal body wrench while the locking screw is firmly seated using the T-handle with the Allen wrench. An audible squeak is often heard when the body is locked and fully seated onto the stem.
19) Is there an offset or lateral proximal body?
Yes, there is both a standard and offset proximal body.
20) How much more offset does the lateral proximal body provide?
There is 4mm more offset in the lateral proximal body.
21) What stem lengths are available for the LMRH?
There are two stem lengths: 140mm and 200mm.