TO THE EDITOR:
In "Arthrodesis of the Knee with a Modular Titanium Intramedullary Nail" (79-A: 26—35, Jan. 1997), Arroyo et al. described a mixed group of twenty-one patients, some of whom had a failed total knee arthroplasty and some of whom had a tumor; all were managed with a modular titanium intramedullary nail to aid in achieving fusion of the knee. The rate of complications was high (38 per cent), with three noteworthy peroneal nerve palsies.
I would like to point out the following.
1. At least one other study in the literature1, which was not cited, demonstrated a markedly lower rate of complications.
2. Insertion of an intramedullary rod in the femur across the knee and tibia is generally thought to be unacceptable in a patient who has a failed total knee arthroplasty associated with infection1. Two of three patients who had this diagnosis in the study by Arroyo et al. had moderate pain two and one-half years postoperatively.
3. A failed total knee arthroplasty for which an arthrodesis is chosen as treatment usually represents a difficult, if not desperate, situation. It should be stressed that the specific operative approach, including the fixation, needs to be individualized, not generalized1. The abnormal anatomy of the specific patient dictates the best fixation1.
Samuel J. Chmell, M.D.: Humana Health Care Plans, 2545 South Dr. Martin Luther King Drive, Chicago, Illinois 60616
Dr. Arroyo, Dr. Garvin, and Dr. Neff reply:
We agree that many options are available for arthrodesis of the knee. It was not our intent to suggest that the modular nail system is indicated for every arthrodesis. We described our experience and results with this system, which we used primarily after resection of a tumor (sixteen patients) and less frequently after failure of a total knee arthroplasty (five patients, three of whom had the failure because of infection).
Arthrodesis of the knee after a failed total knee arthroplasty is challenging, particularly when there is substantial bone loss or infection. Dr. Chmell considers the placement of an intramedullary rod across the knee unacceptable when there is a history of infection. We believe that this statement is broad and inaccurate. The literature supports reimplantation of knee components after eradication of an infection, and we believe that this can be extrapolated to an intramedullary rod for arthrodesis of the knee. In our article, we cautioned readers that there must be absolute certainty that the infection has been eradicated before a modular nail is used after a knee arthroplasty associated with infection.
Regarding our rate of complications, it is in line with that in other large series in the literature2-5. There were three peroneal nerve palsies, which we attributed to resection of a large tumor around the knee and not to the instrumentation.
Finally, we did not purposefully omit the article1 cited by Dr. Chmell. However, in reviewing that article, we found it to be a small series in which many techniques had been used for arthrodesis. Behr et al.1 achieved a successful arthrodesis in eight of their nine patients. They reported two complications—a rate that is unlikely to be significantly lower than that in our series or in other large series in the literature.
Julian S. Arroyo, M.D.; Kevin L. Garvin, M.D.; James R. Neff, M.D.: Department of Orthopaedics, University of Nebraska Medical Center, 600 South 42nd Street, Omaha, Nebraska 68198-1080