High-energy blunt or penetrating trauma to the lower extremity may result in loss of limb. Amputation may be performed on an emergency basis because of arterial injury and/or life-threatening blood loss, or within the first few days after injury because of non-reconstructable bone and/or soft-tissue injury1-3. Occasionally, patients may opt for later amputation because of infection, malunion, nonunion, arthrosis, or pain from other sources. A below-the-knee or transtibial amputation is the most common treatment in such situations. Prosthetic fitting is reliable after transtibial amputation when the amputation was performed outside of the zone of injury, and most patients obtain very good ambulatory ability2,4. However, some injuries generate massive bone loss of the tibia and/or soft-tissue destruction around the proximal part of the tibia and the knee that preclude the performance of a transtibial amputation, in which case an amputation at a more proximal level is required. Both knee disarticulation and transfemoral amputation result in loss of the native knee and loss of length of the mechanical lever arm of the limb, which greatly increase the amount of energy required to walk, even with a prosthesis4-8. An alternative technique was previously developed to “salvage” a transtibial amputation level by using a rotational osteocutaneous pedicle flap transfer from the foot9,10. Osseous length and soft-tissue coverage can be augmented with the flap to provide a functional transtibial amputation if there is an uninjured or minimally injured foot on the same leg. Portions of the calcaneus and associated skin and soft tissues are secured to the remaining proximal part of the tibia and surrounding soft tissues, preventing flap migration. The neural and vascular attachments to the hindfoot structures are maintained, providing a durable, sensate surface for prosthetic fitting.
The purpose of this study was to examine the clinical results and functional outcomes of patients who had salvage of a transtibial amputation level with a rotational osteocutaneous pedicle flap from the ipsilateral foot. We hypothesized that (1) patients who undergo osteocutaneous pedicle flap transfer for transtibial amputation would require more secondary procedures compared with patients who undergo conventional transtibial amputation after trauma and (2) the clinical results and functional outcomes after osteocutaneous pedicle flap transfer may be similar to those after transtibial amputation within the zone of injury.
Surgical Technique
The osteocutaneous flap is based on the posterior tibial vascular pedicle with preservation of the deep plantar arch9,10. The flap is developed by incising the leg on the medial aspect and across the posterior aspect of the distal part of the tibia and extending the incision distally to the level of the first metatarsophalangeal joint. A full-thickness flap of plantar tissue is developed by subperiosteal dissection posteriorly and laterally. The subtalar and calcaneocuboid joints are disarticulated, and the calcaneus is retained without disruption of the plantar pad and surrounding medial and lateral soft tissues. The posterior tibial nerve and tibial artery are preserved, maintaining sensation and vascularity to the flap through the medial and lateral plantar branches. Resection of the proximal part of the tibia and debridement of the adjacent soft tissues are performed. The margins of the proximal part of the tibia are resected and contoured with an oscillating saw as needed to provide appropriate surface area for reception of the calcaneus. The tibial tubercle and extensor mechanism of the knee are carefully preserved. An oscillating saw is used to remove articular cartilage from the subtalar joint and to modify the shape of the calcaneal tuberosity as needed. The shape of the cancellous bone of the calcaneus is adjusted on the basis of the proximal tibial anatomy. The calcaneus is rotated with the plantar tissue directed anteriorly, and the calcaneus is secured and compressed against the proximal part of the tibia with a large-fragment plate (Figs. 1-A and 1-B). The fibula is resected obliquely to a level approximately 2 cm proximal to the length of the retained tibia and calcaneus. Redundancy in the neurovascular bundle is controlled by gently allowing it to assume a circular configuration and by placing it within the deep soft tissues posterior to the retained proximal part of the tibia to prevent the vessels from kinking.
The surrounding soft tissue is closed in layers. Weight-bearing is advanced over the first two months depending on healing of the soft tissues and bone.
Outcomes
Patients completed two functional outcome questionnaires: the Musculoskeletal Function Assessment (MFA) and the Sickness Impact Profile (SIP). Both are generalized health status instruments, with the MFA having a greater focus on musculoskeletal function11,12. There are ten categories within the MFA: mobility, hand and fine motor, housework, self-care, sleep and rest, leisure and recreation, family relationships, cognition and thinking, emotional adjustment and adaptation, and employment. Each category is scored independently, and an overall score can be calculated. Values range from 0 to 100, with low scores indicating better function. The SIP has twelve categories: walking, mobility, body care and movement, social interaction, alertness, emotional behavior, communication, sleep, eating, work, home management, and recreation13-15. SIP scores range from 0 to 100 points. The MFA and SIP have been documented to be reliable and valid outcomes instruments postinjury11,15. Normative and injury reference values for the MFA have been established12. SIP scores of >10 points indicate substantial disability13-15. Differences of 2 to 3 points represent clinically relevant differences in function13-15. The amputees in our study were examined by a trained observer not involved in their care. A 100-ft (30.5-m) timed walking test7,16 was performed, and information about physical function, employment, and mental health was acquired. Patients provided informed consent to participate, and this project was approved by our institutional review board.
Statistical Methods
Clinical outcome variables included complications and secondary operations. Functional outcomes included MFA and SIP scores and walking speed. Bivariate analysis was used to test the association between the possible predictive variables and these outcomes. The variables included age, sex, education, employment, and mental illness. Associations between clinical outcomes and functional outcomes were also examined. A Fisher exact test was used to identify associations between the clinical outcomes and the predictive variables. A Student t test was used to identify associations between functional outcomes and the predictive variables. The Student t test was also used to identify associations between the functional outcomes and the clinical outcomes. In all cases, p < 0.05 was considered significant.
Source of Funding
No external funding was provided for this project.
Patients who had undergone an osteocutaneous pedicle flap procedure with use of the ipsilateral foot for salvage of a transtibial amputation level were identified. Because of bone and/or soft-tissue injury, none of these patients could have been treated satisfactorily with a conventional transtibial amputation because it could not have provided functional length and durability. The records of fourteen patients treated at a level-I trauma center between 1994 and 2006 were retrospectively reviewed. Pertinent patient demographics including injury mechanism and comorbidities are presented in Table I. Injury mechanisms included six motorcycle collisions, four automobile collisions, two industrial injuries, one pedestrian struck by a motor vehicle, and one burn injury. Two patients had preexisting type-1 diabetes mellitus, one was morbidly obese, and one had epilepsy. Nine were cigarette smokers, and one of them smoked cigars and cigarettes. Two patients had a history of alcohol abuse.
Associated Injuries and Initial Treatment
Associated lower-extremity injuries were characterized. Thirteen patients had a type-IIIB open tibial shaft fracture. Four of them also had an ipsilateral open tibial plafond fracture, one had an ankle fracture, and one had a bicondylar tibial plateau fracture. Three patients had an ipsilateral open femoral shaft fracture treated with debridement and antegrade intramedullary nailing on the day of injury. Another patient had open fractures of the ipsilateral patella and lateral femoral condyle treated with debridement and open reduction and internal fixation on the day of injury. One patient had an ipsilateral open knee dislocation treated with urgent debridement followed by collateral ligament and capsule repair forty-eight hours after injury. Ipsilateral foot injuries included a talar body fracture in one patient and metatarsal fractures in two patients.
One patient sustained multiple open fractures in the contralateral leg with associated vascular injury and was treated with emergency transfemoral amputation on that side. Two other patients had contralateral fractures that were treated surgically: one had a femoral shaft fracture, and another had fractures of the tibial plateau and ankle.
Initial surgical debridement of open fractures was performed within six hours after admission to the trauma center in all cases. Provisional stabilization was achieved with external fixation (n = 8), plate fixation (n = 2), or intramedullary nailing of the tibia (n = 1). One patient had dual plate fixation of an ipsilateral bicondylar tibial plateau fracture on postoperative day two. Osteocutaneous pedicle flap transfer was performed at a mean of 9.4 days (range, four to twenty-one days) after the injury. A mean of 3.4 procedures for debridement and provisional stabilization of the leg were undertaken prior to the definitive flap procedure (Figs. 2-A through 2-E). On average, an additional 7.1 cm (range, 5.8 to 8.2 cm) of osseous length was obtained when the calcaneus was secured to the tibia.
The original study population consisted of ten men and four women with a mean age of 43.2 years (range, twenty-four to sixty-four years). Two patients had less than two years of follow-up; they were followed for a mean of eighteen weeks (ten and twenty-six weeks) after their last surgery and did not have any complications or reoperations during that time. The mean duration of follow-up was 60.2 months (range, twenty-four to 119 months) for the other twelve patients. The initial injury was a type-IIIB open tibial fracture in eleven of the twelve patients and extensive soft-tissue loss secondary to a burn without an underlying fracture in one patient.
In the early post-reconstruction period, seven of the fourteen patients required a total of twelve additional procedures for wound debridement, delayed wound closure, or skin-grafting. All wounds were healed within ten weeks. Prosthesis usage began at a mean of 11.4 weeks (range, eight to fifteen weeks). Four patients were treated for infection. One patient had an early deep infection requiring surgical debridement and intravenous antibiotics. Two patients had an early superficial infection and were treated with intravenous antibiotics without additional surgery. One patient presented with a deep infection six months after the index procedure; it required operative debridement, hardware removal, and intravenous antibiotics. No patient had recurrence of infection, and no patient required subsequent revision to a transfemoral amputation level, to our knowledge. There were no nonunions of the calcaneus to the tibia. Three patients underwent three late procedures to improve stump integrity and prosthetic fit and thus promote longer daytime prosthetic wear. Two of them had scar revision and excision of heterotopic bone, and one had scar revision and implant removal.
Twelve patients had a minimum of twenty-four months of follow-up and completed questionnaires. Knee flexion averaged 139° (range, 120° to 150°). No patient had a flexion contracture. The patients were able to perform the timed walking test in a mean of seventeen seconds (range, six to thirty-one seconds), or 5.9 ft (1.8 m) per second. Eleven of the twelve patients achieved a walking speed of >4 ft (1.2 m) per second. Two patients used a cane to assist their walking during the test. Eleven patients reported wearing their prosthesis all day on a regular basis, but two of them removed the prosthesis approximately once per day because of mild pain. One patient reported wearing his prosthesis during the day for up to six to eight hours at a time. Narcotic pain medications were not being used at the time of latest follow-up, but five patients reported intermittent usage of over-the-counter pain medications, including Tylenol (acetaminophen) or nonsteroidal anti-inflammatory drugs.
The MFA scores ranged from 11 to 48 with a mean score of 35.4, which represented moderate functional disability. The SIP scores ranged from 1.6 to 33, with a mean of 13.0. Nine of the twelve patients had a SIP score of >10 points, suggesting substantial residual dysfunction. With the numbers available, we were unable to identify associations between outcome scores and age, sex, complications, secondary operations, or other injuries. Notably, one patient had an elbow injury, and one patient had a contralateral transfemoral amputation.
Five patients returned to their same employment after the injury (see Appendix). One patient who was unemployed prior to his injury was working as a bridge inspector at the time of writing. The two patients with work-related injuries and Workers’ Compensation claims had not returned to employment at the time of the most recent contact; thus, 17% reported an inability to return to work at the most recent contact. Two of four women and four of eight men reported treatment for mental illness since their injury, unrelated to employment status. Three of the eight patients who were married received treatment for mental illness related to the injury compared with three of the four who were not married (p = 0.27). With the data available, we were unable to identify relationships between functional outcome scores and education, employment, or presence of mental illness.
To perform a conventional transtibial amputation, a minimum of 9 cm of the proximal part of the tibia must be intact4. A durable soft-tissue envelope is also essential, preferably with muscle coverage of the distal aspect of the tibia to prevent damage to the skin with daily prosthetic wear5,17-19. Some injuries generate bone loss from the proximal part of the tibia and/or soft-tissue loss around the tibia and knee, which preclude performance of a transtibial amputation, requiring an amputation at a more proximal level. The described technique permits salvage of a transtibial amputation via reconstruction with a rotational osteocutaneous pedicle flap transfer from the foot9,10,20. This procedure can be considered when the ipsilateral foot is uninjured or minimally injured and there is an intact arterial supply to the plantar surface (Table II). Contraindications include a comminuted calcaneal fracture, which would preclude fixation of the calcaneus to the proximal part of the tibia; degloving or devascularization of the plantar heel pad; and an inadequate extensor mechanism for the knee.
When the amputation is undertaken, portions of the calcaneus and associated heel pad and other soft tissues are retained, with their native arterial and nerve supply10. Since the tissue is rotated on the neurovascular pedicle, vascular reanastomosis is not required, avoiding free tissue transfer. The flap is secured to the proximal part of the tibia and surrounding tissue that were injured, producing a sensate stump of sufficient length and soft-tissue durability to promote ambulation and function. We have not identified problems with prosthetic fit due to the shape of the calcaneus. The native knee is also preserved. Fixation of the calcaneus to the tibia not only provides additional stump length; it also prevents flap instability. None of our patients had nonunion of the tibia to the calcaneus, and none required revision amputation to a more proximal level.
One prior report described a rotational island flap of the dorsal foot skin and anterior tibial artery to preserve length after transtibial amputation21. The technique we have described is similar but provides additional osseous length as well as the secure durability of the plantar pad and calcaneus as a weight-bearing surface, while preventing flap instability. Another recent case report described salvage of a transtibial amputation level in a patient with proximal tibial bone loss after trauma through the performance of rotational transfer of the distal part of the tibia, with maintenance of the posterior distal tibial soft-tissue attachments22. This tactic was similar to our technique in that it provided a composite of bone and soft-tissue augmentation to preserve a transtibial amputation. However, if the zone of injury involves the bone and soft tissue of the distal part of the tibia, a more distal rotational flap is necessary.
Previous literature has indicated that walking and patient satisfaction after transtibial amputation are superior to those after transfemoral or knee disarticulation amputation7,8,17,23,24. The primary benefit of the flap that we have described is preservation of a durable transtibial amputation level. To our knowledge, no one has compared the osteocutaneous pedicle flap transfer technique with conventional amputations. The Lower Extremity Assessment Project (LEAP) was initiated several years ago to characterize patients with limb-threatening lower-extremity trauma1,23. Approximately one-quarter of these patients had an amputation. Eighty-one LEAP patients with a transtibial amputation were evaluated twenty-four months after injury7. Thirty percent had at least one rehospitalization for a major complication. Seventeen percent had infection, a rate that is similar to that in our study. Forty percent of the LEAP patients with transtibial amputation had an atypical flap closure, and 12% had surgery for stump revision. It was reported that 9.3% did not have complete soft-tissue healing after two years7. In our population, all patients had soft-tissue healing within ten weeks. However, 50% had early secondary operations to promote soft-tissue healing, and 25% had late stump revisions because of heterotopic bone and scar tissue, suggesting that the osteocutaneous pedicle flap transfer is associated with more surgical procedures to achieve a durable transtibial amputation level. Because of the increased complication rate associated with this procedure, it also may not be suitable for some patients who are systemically ill or who have other medical problems.
Walking speed was reasonable after osteocutaneous pedicle flap transfer and prosthetic fitting, as eleven (92%) of our twelve patients achieved a speed of >4 ft per second. This is substantially higher than speeds in other reports of transtibial amputation for lower-extremity trauma7. Two (17%) of our twelve patients reported an inability to return to employment after a mean of five years. Similarly, in the LEAP study, up to 25% of patients (including those who had an amputation and those with salvage of the limb) reported limitations in their ability to return to employment25,26. Higher rates of work ability have been associated with younger age, higher education, and increased self-efficacy (self-worth, productivity, or self-respect), and overall patient satisfaction is related to the ability to return to work, improved physical function, and less psychological distress7,26,27.
Half of our patients had mental illness after their injury. However, our study was limited by the small number of patients, and we were unable to identify an association between functional outcome scores and education, employment, or the presence of mental illness. Despite this, the mean MFA and SIP scores demonstrated substantial residual dysfunction in our patients at the time of the most recent follow-up. Our mean SIP score of 13.0 is not substantially different from that of the patients with a transtibial amputation in the LEAP study (mean, 12.7) after two years7. Not all LEAP patients had amputation within the zone of injury. Another limitation of our study is that we compared patients who had undergone salvaged transtibial amputation with LEAP patients who had undergone transtibial amputation, rather than with our own patients who had undergone conventional transtibial amputation; however, the LEAP group does provide a similar, large cohort of trauma patients for comparison. Population-normal SIP scores are 2 to 3 points13,15. Among the LEAP patients, worse SIP scores were associated with lower levels of education, non-white race, an age of less than fifty-five years, chronic preexisting medical conditions, and low self-efficacy7. Psychosocial function remains critical to optimizing patient satisfaction and outcome28-31. Future work to address these issues and to propose interventions could be beneficial. Additionally, meticulous surgical technique and preservation of durable stump length should be encouraged to minimize complications and to enhance outcomes.
In conclusion, a novel technique has been developed to salvage a transtibial amputation in the absence of adequate tibial length and/or soft-tissue coverage for a conventional transtibial amputation level. Additionally, in the presence of adequate soft-tissue coverage, this procedure can add length to a short transtibial amputation, making the stump sensate, durable, and more functional for prosthetic wear. More secondary surgical procedures to achieve a durable stump are required with this flap technique compared with a standard transtibial amputation after trauma. Moderate-term follow-up demonstrated good walking ability and stump durability in these patients. Walking times were better and SIP scores are similar to those in other reports of transtibial amputation for severe trauma. Although half of the patients received treatment for mental illness, only two did not return to employment. This technique provides a reliable, functional alternative to more proximal amputation after severe lower-extremity injury.
Disclosure: None of the authors received payments or services, either directly or indirectly (i.e., via his or her institution), from a third party in support of any aspect of this work. One or more of the authors, or his or her institution, has had a financial relationship, in the thirty-six months prior to submission of this work, with an entity in the biomedical arena that could be perceived to influence or have the potential to influence what is written in this work. No author has had any other relationships, or has engaged in any other activities, that could be perceived to influence or have the potential to influence what is written in this work. The complete Disclosures of Potential Conflicts of Interest submitted by authors are always provided with the online version of the article.