Letter to the Editor

To the Editor:

We have read with interest the article from Paul Dougherty, MD, “Transtibial Amputees from the Vietnam War: Twenty-eight-Year Follow-up” (JBJS 83-A: 383-389, March, 2001).

The stated goal of the article was to determine long-term follow-up of patients who had sustained a battlefield injury resulting in an amputation. Further, a comparison was made in the paper between patients who had undergone amputation without osteoplasty and patients who had undergone an Ertl osteoplasty. As surgeons and a prosthetist that routinely employ and manage patients who have undergone the osteomyoplastic technique as described by Ertl, we request the author to clarify some issues. We also feel the article contained several inaccuracies, and therefore submit clarifying comments. Our questions and comments are listed below:

1) Several terms are used within the paper: Ertl osteoplasty, Ertl Transtibial Amputation, and the Ertl procedure. There is considerable misconception regarding the principles that constitute the foundation of the procedure, as well as the tissues that are involved, and precisely what the “Ertl Procedure” is. Briefly, in the below-knee-amputation, the Ertl procedure is an osteomyoplastic amputation technique incorporating an osteoplasty procedure to close the medullary canal and obtain a tibio-fibular synostosis such that the patient may be end bearing.1, 8 Periosteal tissue, fibular graft, rib graft, or a combination of these tissues have been utilized. The addition of a myoplasty provides improved soft tissue coverage over the synostosis by bringing the antagonistic muscles together, maintaining residual muscle function and improving regional blood flow.1, 2, 3, 4, 5, 6, 7, 8 At Valley Forge, only the osteoplasty portion of the procedure was performed. Therefore, the terminology used with in the article is not interchangeable and should not be used in this fashion. This creates misunderstanding regarding the correct application of these terms to the surgical procedures. The results obtained in this study should not make the assertion that no statistical difference existed between the Ertl procedure and non-Ertl amputation patients. Only that in this small group of patients with a 41% loss of follow-up, no statistical difference was noted with the data presented between patients who received an osteoplasty amputation versus a non-osteoplastic amputation. 

2) Within the Materials/Methods section of the paper, the SF-36 questionnaire for all contacted amputees was to be compared to normative values within the forty-five to fifty-four age group. Normative values are available for a wide range of age groups, including greater than sixty-five years old. Based on the range of follow-up reported in the Results section, the potential age for some patients would have been greater than fifty-four years of age. We question the use of limited normative parameters in the paper as a potential limiting factor when comparing SF-36 results. If patients within the study group were older than fifty-four, should they have had their SF-36 result compared with an equal age matched group? If study patients fell outside the fifty-four age group parameter, would their SF-36 comparison be negatively skewed to a lower result when compared to the forty-five to fifty-four age group?

3) In accruing patients for the present study, it was stated that the amputee service at Valley Forge was established in February 1, 1969. However, the range of follow-up was up to 35 years, which would put the potential date for follow-up from Valley Forge at 2004. Would the author please clarify this apparent disparity in dates and time? It would suggest that patients had received some or all of their care elsewhere prior to transfer to Valley Forge.

4) As pointed out by the author, in patients with multiple injuries, any amputation may be functional yet the SF-36 score would be expected to be lower due to multiple injuries. In the Results section, the comparison of the SF-36 results between non-Ertl amputees and Ertl osteoplastic amputees were made. However, for each amputation technique, it appears group I and group II patients were combined. Grouping the patients together for comparison would therefore make the results and conclusions regarding outcomes between non-Ertl and Ertl osteoplastic patients skewed to a lower outcome and potentially invalidate a comparison. The data should have been kept separate and reported as group I non-Ertl vs. group I Ertl osteoplastic amputees and group II non-Ertl vs. group II Ertl osteoplastic amputees. Would the author be able to supply that comparison at this date as a follow-up to his study?

5) In the results section, it was documented on the number of prosthetic revisions the patients had undergone. To optimize the surgical technique for amputees who have undergone an Ertl procedure, the ideal prosthesis socket design would incorporate a tolerable percentage of the bodyweight being supported under the terminal synostosis, i.e. end loading. End loading is then increased in an axial fashion as the amputee increases their functional capability. The remainder of the amputee’s bodyweight is also distributed in a total-surface-bearing fashion through the remainder of the residual limb.10, 11 During the author’s data collection, was he able to determine the prosthesis socket design created for the amputees in both groups? Were Ertl osteoplastic amputees utilizing an end bearing designed prosthesis? If not, could this have contributed to the perceived difference in SF-36 scores?

6) There was no discussion regarding the potential differences between non-Ertl and Ertl osteoplastic amputees at the conclusion of the article. This appears to be a significant finding, as reported in the results section, and would be an important topic to discuss based on the stated goal of the paper. Would the author be able to comment at this time based on his observations and the presented data, why there were no perceived differences between the non-Ertl and Ertl osteoplastic patients?

Johann Ertl, M.D. first noted the regenerative capabilities of periosteal tissue through clinical observations in the early 1900’s.9 These observations were applied surgically to cranial reconstruction, facial/mandibular reconstruction, mal-unions, non-unions, spine fusion, and amputation surgery. He presented the principles and technique of the “Ertl Procedure” at a conference for surgery in Berlin 1937. He later published his principles and techniques in his book, “Regeneration: Ihre Anwendung in der Chirurgie”, Verlag von Johann Ambrosius Barth, Leipzig, 1939.8 From that time, various authors have written and lectured on this procedure.  The vast majority of these authors inaccurately and incompletely describe Dr. Ertl’s methods. We feel it is important to understand what the Ertl Osteomyoplastic Amputation Surgical Technique entails and therefore have provided these additional comments. Further, not only with sound surgical practice, we would agree that a comprehensive program involving emotional, psychological, and rehabilitative support is needed to provide an amputee with the greatest potential for recovery. We would encourage the Department of Defense to implement such a program for amputees in designated centers.

References

  1.  Ertl J. Über Amputationsstümpfe. Der Chirurg 20(5): 218-224, 1949.
  2.  Dederich R. Plastic treatment of the muscles and bone in amputation surgery. Joun Bone Joint Surg  45B(1): 60-66, 1963.
  3.  Hansen-Leth C. Muscle blood flow after amputation with special reference to the influence of the amputation level. Acta Orthop Scand 48: 10-14, 1977.
  4.  Hansen-Leth C, Reimann I. Amputations with and without myoplasty on rabbits with special reference to the vascularization. Acta Orthop Scand 43: 68-77, 1972.
  5.  Erikson U, Olerud S. Healing of amputation stumps, with special reference to vascularity and bone. Acta Orthop Scand 37:  20-28, 1966.
  6.  Hansen-Leth C. The vascularization in the amputation stumps of rabbits. A microangiographic study. Acta Orthop Scan 50: 399-406, 1979.
  7.  Hulth A, Olerud S. Studies on amputation stumps of rabbits. Journ Bon Joint Surg 44B(2): 431-435, 1962.
  8.  Ertl J. Regeneration; ihre Anwendung in der Chirugie. Verlag von Johann Ambrosius Barth, Leipzig 1939.
  9.  Ertl J. Die Chirurgie der Gesichts- un Kieferdefekte. Urban & Schwarzenberg, 1918.
  10.  Stokosa JJ. New Developments in Prosthetics, In: Moore WS and Malone JM, eds. Lower Extremity Amputation, , W.B. Saunders Company, 1989.
  11.  Stokosa JJ. Prosthetics for Lower Limb Amputees, In: Haimovici H, Ascer E, et al eds. Haimovici’s Vascular Surgery, 4th ed, Boston: Blackwell Science, Inc, 1996.