Transtibial Amputees from the Vietnam War

To the Editor: We have read with interest the article, “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 the long-term follow-up of patients who had sustained a battlefield injury that resulted in an amputation. The author compared patients who had undergone amputation without osteoplasty and patients who had undergone an Ertl osteoplasty.

As surgeons and a prosthetist who routinely perform the osteomyoplastic technique as described by Ertl,and manage these patients, we would offer some comments and request that the author clarify some issues. Our questions and comments are listed below:

Several terms are used within the paper: Ertl osteoplasty, Ertl Transtibial Amputation, and the Ertl procedure. There are misconceptions regarding the principles of the procedure, as well as the tissues that are involved, and there is no precise definition of the “Ertl Procedure”.

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 (8). From that time, various authors have written and lectured on this procedure, at times inaccurately and incompletely describing Dr. Ertl’s methods. We would define the Ertl procedure as an osteomyoplastic amputation technique that incorporates an osteoplasty to close the medullary canal and creates a tibio- fibular synostosis to potentially achieve an end bearing extremity.(1, 8) Osteoperiosteal flaps, fibular graft, iliac crest, rib graft, or a combination of these tissues have been utilized to achieve synostosis. 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) In this paper, only the osteoplasty portion of the Ertl procedure was performed. Therefore, the terminology used in the article was not accurate.

The results reported in the study should not assert that no statistical difference existed between the Ertl procedure and non-Ertl amputation patients. Perhaps a more accurate assertion would be that in this small group of patients with a 41% loss to follow-up, no statistical difference was noted between the two groups with the numbers available.

In the Materials/Methods section, 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 may have been less than 45 and greater than fifty-four years of age. We question the use of limiting the number of patients to be included in the study when normative parameters for other age groups are available in the literature. If additional patients were available to be included in the study population, could this have provided the study with a greater sample of patients for comparison?

As noted by the author, in patients with multiple injuries, an 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 osteoplastic amputees and Ertl osteoplastic amputees was 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 as a follow-up to his study?

In the Results section, the number of prosthetic revisions the patients had undergone was documented. To optimize the surgical technique for amputees who have undergone an Ertl procedure, the ideal prosthetic 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 gains 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 prosthetic 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?

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 why there were no perceived differences between the non-Ertl and Ertl osteoplastic patients? Finally, we would state that in addition to sound surgical practice, 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.