We read with interest the case report by Dr. Cavadas et al. “Bilateral Transfemoral Lower Extremity Transplantation at One Year” . This article highlights the challenges both in the operating room and in the first 12 months of postoperative management of the first reported bilateral lower extremity vascularized composite allotransplantation (VCA). Despite the technical success described in this manuscript, several questions regarding the optimal management for this and subsequent patients with bilateral transfemoral amputations (BTFA) remain. Indeed, given the expanding treatment options for this condition, enthusiasm for VCA in this setting could perhaps be called into question.
In the article, the operative details and the rationale for the sequence of events for lower extremity VCA are clearly described. However, before discussing the broader questions surrounding this demonstration of lower extremity VCA, one technical point from the operation merits immediate concern. Given the uncertainty of healing osteotomies following VCAs, we would recommend stabilization with large-diameter, statically locked intramedullary nails instead of the bone fixation with locking plates and screws to allow for immediate weight bearing and ostensibly a lower risk of implant failure or nonunion . In addition, regarding the future rehabilitation of the patient, the reported knee extensor lags place him at high risk for falls, which is not a minor concern in the setting of osteotomy nonunion and locking plates and screws. Failure of this type of fixation, if it occurs, is likely to be immediate and catastrophic, and is eventually inevitable if solid union does not develop. Although these two points are easily addressable in future attempts, several issues remain as to the future viability of this approach given the current experience with casualties from combat operations who suffer similar (oftentimes more extensive) injury patterns.
The endocrine and infectious complications as well as the rejection episodes suffered by the patient were related to the immunosuppressive regimen required for VCA. Although the patient underwent appropriate management for these complications with no short-term impairment to his rehabilitation, these morbidities elucidate major issues with life-long immunosuppression inherent to treating a BTFA patient with VCA in the face of known effective prosthetic and rehabilitation options.
Patients with bilateral upper extremity amputation have benefited from upper extremity transplantation in that this VCA has demonstrated impressive results in returning prehensile function to patients, which is otherwise difficult to replicate with prosthetics. Conversely, patients with BTFA have generally adapted well to modern prostheses with excellent success rates for return of independent functional ambulation and even running. Specific to the patient in this manuscript, prosthetic advances such as microprocessor knees have allowed for more efficient and safer ambulation, even in the setting of high BTFA .
In our center's experience with hundreds of wounded warriors with amputations, we have witnessed amazing functional results. This has largely been attributed to early aggressive multidisciplinary rehabilitation and prosthetic training, which have succeeded despite numerous acute and chronic morbidities from the polytraumatic nature of the common injury patterns for these combat casualties . There are several success stories from this program known to the editorial authors, including one of a wounded warrior with BTFA who completed a marathon.
For BTFA patients who are not able to achieve community ambulation with rehabilitation and traditional prostheses, osseointegration is an option in Europe with low treatment failures and excellent functional results . This two-stage surgical procedure incorporates titanium implants and permits direct attachment of bone-anchored prostheses, allowing for improved limb function and eliminating socket- and fitting-related complications. Standardized protocols for this procedure and rehabilitation have reduced failure rates and improved quality of life for patients.
Based on the manuscript by Dr. Cavadas et al., we find that it is technically feasible to perform this procedure with nerve regeneration results similar to upper extremity VCA transplants. However, the reported patient has not achieved the primary end point of regular, independent community ambulation or demonstrated any superior clinical benefit compared to the aforementioned alternatives. Further, the patient has suffered multiple complications in the 12 postoperative months, thus bringing both the efficacy and safety of this procedure into question. The authors of this editorial would infer that a center, which can perform a bilateral lower extremity VCA should also have the capacity for advanced rehabilitation with traditional prostheses or osseointegrated prosthetics for patients with BTFA. In our experience, the rare patient with long BTFA who is effectively nonambulatory following intensive rehabilitation generally lacks the motivation necessary to achieve this goal, which raises a final issue with regard to the careful selection of dedicated patients for experimental procedures such as bilateral lower extremity VCA.
Future applications of bilateral lower extremity VCA are therefore uncertain at this time. Further research into the well-established methods of BTFA management is needed to help better define the group of BTFA patients who would be predicted to fail both rehabilitation and osseointegration, and to understand why these failures occur. Also, additional investigation into bilateral lower extremity VCA and its applications should be considered in the preclinical setting. Until the efficacy of bilateral lower extremity VCA and the limitations of current rehabilitation methods can be better understood, one of the tenants of solid surgical judgment still holds true—“just because you can, does not mean that you should.”