To The Editor:
I would like to make a few observations regarding the article "Mennen
Plate Fixation for the Treatment of Periprosthetic Femoral Fractures. A
Multicenter Study of Thirty-six Fractures" (2002;84:2211-5), by Noorda
and Wuisman.
The study reviewed thirty-six periprosthetic fractures that had been
treated at twenty-one institutions in The Netherlands, which amounted to an
average of 1.7 operations per institution and, therefore, per surgeon. One has
to conclude that these surgeons had limited experience with the procedure and
thus were novices with respect to the technique. The article quite clearly
stated that, in the majority of cases, the postoperative management was not
followed as proposed by the instruction manual. The cases described in the
study ranged from the worst possible fractures to the simplest periprosthetic
fractures, which makes a comparative study illegitimate. At least from a
scientific point of view, the different fractures should have been analyzed
and placed into comparative groups. This categorization would allow one to
determine which factors are important and which are prognostic indicators of
outcome that can be used in the treatment of periprosthetic fractures.
It is well known that periprosthetic fractures are difficult to treat. I
know of no system that has had consistently good results, and therefore it is
most important to follow the suggested instructions regarding the technique
and postoperative management. It would be reasonable and more honest to
criticize the incorrect technique rather than the implant.
The percentage of failures cited is incorrect. Eight failures among
thirty-six cases amounts to a rate of 22%—not 28%.
A 72% success rate in a very diverse group of difficult fractures that were
operated on by inexperienced surgeons should certainly not be regarded as
disastrous. Therefore, the conclusion that this plate is not recommended for
periprosthetic fractures makes little sense. Had the surgeons followed the
instructions and gained some experience by performing more than an average of
1.7 operations, the success rate would certainly have been well above 80%. I
would be pleased if the authors of this paper could notify me of any other
procedure with a higher success rate.
We thank Dr. Mennen for his observations regarding our article. The study
was a compilation of the cases of thirty-six fractures collected from
twenty-one institutions in The Netherlands. In fifteen institutions, the
experience of each surgeon with the procedure consisted of only one case.
However, in the remaining six institutions, the experience of the surgeons
with the procedure ranged from two to six cases, but these institutions also
had disappointing results. Moreover, because periprosthetic femoral fractures
are rare, we believe the treatment method should be simple and well
established even for a surgeon with limited experience.
The instruction manual (CMW Laboratories, Exeter, England) suggested
postoperative mobilization with use of either ischial weight-bearing calipers
or a functional brace consisting of a thigh cuff to provide auxiliary axial
support but, most importantly, to provide essential rotational control. We
agree with Dr. Mennen that in the majority of cases an external support was
not used postoperatively. Most cases were managed with non-weight-bearing on
the involved limb with crutches until clinical and radiographic signs of union
were present. Although braces might be important after this method of
treatment, their use can be complicated by pressure sores, especially in older
patients and those with peripheral neuropathy.
We classified the fractures according to the system of Johansson et
al.1. In the
Discussion section, the results of Mennen plate fixation were related to the
type of fracture. Type-II and III fractures were more unstable than type-I
fractures.
We presume that Dr. Mennen misinterpreted the results in the article. Not
eight but ten failures were described, and ten failures among thirty-six
fractures is a rate of 28%. Moreover, one more mechanical failure of the plate
(with union of the fracture) increased the rate to 31%.
We agree with Dr. Mennen that the success rate of procedure is not
disastrous. However, on the basis of our study (with the highest number of
patients in the literature, to our knowledge and a review of subsequent
reports in the
literature2,3,
we believe that the mechanical properties of the Mennen plate cannot withstand
the weight-bearing forces associated with fractures of the femur.
Johansson JE, McBroom R, Barrington
TW, Hunter GA. Fracture of the ipsilateral femur in patients with total
hip replacement. J Bone Joint Surg Am.1981;63:
1435-42.631435
1981
[PubMed]
Hagroo GA, Qurashi V, Butt MS.
Breakage of Mennen femur device. Injury.1996;27:
593-5.27593
1996
[PubMed][CrossRef]
Liu AM, Flores M, Nadarajan P.
Failure of Mennen femoral plate. Injury.1995;26:
202-3.26202
1995
[PubMed][CrossRef]