TO THE EDITOR:
I read with interest "A Femoral Component Inserted without Cement in Total Hip Arthroplasty. A Study of the Tri-Lock Component with an Average Ten-Year Duration of Follow-up" (80-A: 952—960, July 1998), by Burt et al., and I would like to comment on the nomenclature that is currently in vogue with regard to total hip arthroplasty. It seems curious that a paper should be given a title or that a prosthesis should be described with negative terminology. I refer to the use of "without cement" in this title and "cementless" in much of the orthopaedic literature.
While cement was the mainstay of early joint-replacement procedures, there is now a large volume of literature describing components that are designed to be fixed by means of bone ingrowth or bone ongrowth. Indeed, numerous prostheses that are currently in use are intended to be stabilized by means of bone ongrowth rather than either bone ingrowth or cement fixation. I therefore seek the indulgence of the editors of The Journal to ask that, when a specific prosthesis is used, authors provide a descriptive title that defines the uniqueness of that component on the basis of its design features.
The initial stability of the prosthesis in the article by Burt et al. may have been related not only to the proximal coating but also to the geometry of the design. In addition, although the authors specified the pore size in their description, it may be that the enduring stability of this implant is related to the effect of bone ongrowth rather than bone ingrowth.
The orthopaedic literature appears to describe femoral stems as if there were only two types: those inserted with cement and those designed for bone ingrowth. In contrast, the Alloclassic (formerly Zweymüller) hip, which was introduced in Europe in the late 1970s, is intended to be fixed by means of bone ongrowth as it has no porous surface. A body of literature confirms the efficacy of this device3,4. Similar bone-ongrowth prostheses are manufactured by a number of companies, and it seems that these devices are ignored when generic terminology is used to describe prostheses that are inserted without cement1,2. Prostheses that have a plasma-sprayed coating make up yet another group of implants for which the principal method of biological fixation may be bone ongrowth rather than bone ingrowth.
Therefore, this letter is a plea to all authors and to the editors of The Journal to use titles that accurately reflect the uniqueness of the implant or implants being described and also to avoid using generic terminology in the title that does not accurately reflect the content of the paper.
Bruce R. T. Love, F.R.A.C.S.: East Melbourne Orthopaedic Clinic, 518 Victoria Parade, East Melbourne 3002, Australia
Dr. Burt, Dr. Garvin, Dr. Otterberg, and Dr. Jardon reply:
We thank Mr. Love for his comments. He is correct that we used a general descriptive term in the title. Nevertheless, this term describes how the prosthesis was placed within the femoral canal. The more specific name is the Tri-Lock femoral component, which was clearly described in the Materials and Methods section as a cobalt-chromium, tapered, porous-coated stem. However, we did not believe that it was essential for all of these descriptive terms to be used in the title.
Mr. Love questions the role of surface finish and raises the concern that the long-term stability may be attributed to the geometry of the implant and to bone ongrowth rather than to bone ingrowth. We agree that these are interesting questions, but we did not perform histological analyses in our study and therefore cannot comment on whether there was evidence of bone ingrowth or bone ongrowth.
Finally, the specific name of the Tri-Lock femoral component is unique, but the stem, like any other, can be inserted with or without cement. All of the patients in our study had insertion of the Tri-Lock component without cement. Certainly, it would have been possible to entitle the article "A Porous-Coated Femoral Prosthesis in Total Hip Arthroplasty Inserted without Cement. Average Ten-Year Follow-up of the Tri-Lock Femoral Component." However, it was our belief that this title would have been redundant as it would have named the prosthesis, described the prosthesis, and described how the prosthesis was inserted. As stated, the component was described in the Materials and Methods section.
We fully agree with Mr. Love that titles should be accurate and succinct, and we believe that the title of our manuscript meets these criteria.
Charles F. Burt, M.D.: 4239 Farnam, Suite 409, Omaha, Nebraska 68131
Kevin L. Garvin, M.D.; Erik T. Otterberg, M.D.; O. Max Jardon, M.D.: Department of Orthopaedic Surgery, 981080 Nebraska Medical Center, Omaha, Nebraska 68198-1080