Abstract
Background
Surgical attempts at lower limb preservation after trauma may be complicated by pain and gait disturbances, which can impact the activity level of a military service member. It is unclear how later transtibial amputation (TTA) might affect patients who elect this option after attempts at limb preservation.
Questions/purposes
The purposes of the study were to compare preamputation and postamputation (1) the numeric rating scale for pain and pain medication use; (2) self-reported activity level, Four Square Step Test (FSST) results, and assistive device use; and (3) spatiotemporal variables measured with instrumented gait analysis in individuals who elected TTA after multiple attempts at limb preservation.
Methods
Retrospective review revealed 10 patients with unilateral lower extremity injuries who underwent late TTA between 2008 and 2016. All patients had undergone multiple limb preservation attempts and had completed instrumented gait evaluations as part of their routine care before and after TTA. One patient was excluded as a result of short followup. The remaining nine patients (eight men, 29 ± 6 years) averaged five surgeries before amputation. Injuries were from improvised explosive devices (six), motorcycle accidents (two), and one training accident. Strict indications for amputation were pain, difficulties performing activities of daily living, limited physical function, and medication dependence. Data for the aforementioned purposes were collected by gait laboratory staff before and 8 to 17 months after amputation. Time to TTA after initial injury was 5 ± 3 years. At the start of the gait analysis study, pain was assessed at rest, activity level was recorded by patient report, and the FSST was administered.
Results
After TTA, there was a decrease in pain scores from 4 ± 2 to 1 ± 1 and patients using narcotics decreased from four to only one patient. Self-reported walking endurance increased from 1 ± 1 mile to 7 ± 8 miles and patients able to run increased from one patient to eight with the ninth having no desire to run but bicycled. Patient FSST times improved from 12 ± 10 seconds to 5 ± 1 seconds. No patients required assistive devices after TTA. There were improvements in velocity (108 ± 16 cm/s to 142 ± 7 cm/s), stride length (129 ± 14 cm to 154 ± 8 cm), cadence (101 ± 9 steps/min to 111 ± 7 steps/min), and step width (16 ± 3 cm to 12 ± 2 cm) between pre- and postassessments. Asymmetric single-limb stance time was measured both pre- and postamputation; this did not worsen with the increase in walking velocity.
Conclusions
The findings of this study show that TTA after attempted limb preservation in a young, motivated group of service members after traumatic injuries can be successful in decreasing pain and narcotic use and can allow for high-level functional activities. Future studies will be needed to compare this cohort with patients who underwent early TTA after traumatic injury. However, we acknowledge that the resources and support structure available for this population are unique and may not be readily available to the general population.
Level of Evidence
Level IV, therapeutic study.
Introduction
With the advancement in military medicine, medical treatment in theater, and evacuation to tertiary treatment centers, many injured limbs of military personnel once thought to be candidates for primary amputations have instead undergone limb preservation procedures.
It is widely accepted that the limb preservation pathway does not preclude future amputation. Previous authors have demonstrated that compared with primary amputation, limb preservation is associated with increased rehospitalization, higher complication rates, and an increased number of surgical procedures [9, 11]. The request on the part of the patient to pursue late amputation is an understandable and, at times, a necessary endeavor. However, whether amputation after multiple attempts at limb preservation improves function and pain in patients with lower limb injury is unclear.
Previous research has primarily focused on the initial decision to preserve or to amputate a limb. MacKenzie and Bosse [9] found that Sickness Impact Profile scores demonstrated no difference at 2-year followup in patients who underwent limb preservation compared with those who underwent primary amputation. However, the Military Extremity Trauma Amputation/Limb Salvage (METALS) study found better functional outcomes in patients with early amputation compared with limb preservation in a military population [3]. Krueger et al. [8] found that the most common indications for late amputation after limb preservation were pain and dissatisfaction with the preserved limb. Others have found that late amputation was associated with patients who had severe soft tissue injury requiring flap coverage, postoperative courses complicated by infection, and arterial injuries [6]. Gwinn et al. [5] determined that blast-induced extremity fractures and arterial injuries were associated with higher rates of late conversion of preserved limbs to amputation in the military population. Stinner et al. [15, 16] determined that late amputations, which were defined as occurring > 12 weeks after the initial injury, occurred 15.2% of the time in their cohort. Although risk factors predisposing to late amputation have been identified, very little information exists to assess the outcomes of those who have undergone such procedures.
None of these studies addressed functional gait parameters before and after the amputation. Furthermore, using self-reported functional measures as well as walking speed, others have noted that regardless of the level of amputation, severe disability may accompany amputation after trauma [1, 10].
The purposes of this study were therefore to compare preamputation and postamputation (1) numeric rating system (NRS) for pain and pain medication use; (2) self-reported activity level, Four Square Step Test (FSST) results, and assistive device use; and (3) spatiotemporal variables measured with instrumented gait analysis in individuals who elected transtibial amputation (TTA) after multiple attempts at limb preservation.
Patients and Methods
After approval from the institutional review board at Naval Medical Center San Diego in compliance with all applicable federal regulations governing the protection of human subjects, a retrospective review was performed of the Naval Medical Center San Diego Gait Analysis Laboratory Registry. We sought patients who had undergone late TTA after multiple limb preservation attempts after unilateral lower extremity musculoskeletal injury and had completed gait evaluations before and after their amputation between 2008 and 2017. The review revealed 10 patients, but one was eliminated from the analysis because of lack of gait analysis data around the 12-month time point. Nine patients were identified with complete data preamputation and a mean of 13 months (range, 8-17 months) after amputation.
Eight of the nine patients were men with a mean age of 29 ± 6 years at the time of amputation (Table 1). Eight of the nine patients were active duty at the time of their amputation, whereas the ninth was retired from the military. Six patients sustained injuries as a result of improvised explosive devices while in combat, two patients sustained injuries in motorcycle accidents, and one patient sustained injuries during military training (a high-altitude, low-opening jump). Patients in this cohort elected for a late amputation a mean of 5 ± 3 years after their initial injury. Before amputation, the patients in this cohort underwent a mean of 5 ± 3 limb preservation surgical procedures (range, 2-10). Five patients had a history of osteomyelitis with three reporting that the osteomyelitis had resolved and two reporting chronic or unresolved conditions.
Table 1.
Demographics of the nine-patient population
All patients had been followed closely by the orthopaedics and physical medicine and rehabilitation departments from shortly after the time of injury or since the time of the limb preservation surgeries. Chronic pain, decreased function, and gait disturbance had all been reported by these patients despite the efforts of the multidisciplinary team at the Naval Medical Center San Diego. Before amputation, patients who elected conversion of limb preservation to TTA underwent extensive counseling from two orthopaedic surgeons, evaluation by a mental health professional, and were required to agree to participate in an intensive postoperative multidisciplinary rehabilitation program at the military medical center.
Date of injury, injuries sustained, number of surgical procedures performed before amputation, and time between amputation and gait analysis were collected as part of routine care by gait analysis laboratory staff (Table 1). Additional data noted were body mass index (BMI), self-reported NRS of 0 to 10 where 0 = no pain and 10 = worst pain imaginable, self-reported current activity level, medication use, use of an assistive or orthotic device, and FSST time [2] (Tables 2, 3). The FSST is a validated, timed test administered using a stopwatch and four single point sticks resting in a cross flat on the floor. The aim of the FSST is to complete a stepping sequence through the four squares as fast as possible. It provides an assessment of multidirectional agility and balance. The findings were compared at the two time points, before amputation and postamputation, for the nine patients.
Table 2.
Pre- and postamputation comparisons for nine patients
Table 3.
Running ability and prosthetic foot details for nine patients
Three-dimensional (3-D) instrumented gait analyses were performed with patients walking at their self-selected walking velocity in the Naval Medical Center San Diego Gait Analysis Laboratory. A 12-camera motion capture system (120 Hz; Motion Analysis Corp, Santa Rosa, CA, USA) was used to collect 3-D kinematic data. Each patient walked across a 10-m walkway multiple times until a minimum of six strides per right and left extremities was collected. Kinematic data were quality-checked in Cortex (Motion Analysis Corp) and exported to Visual3D (C-Motion, Inc, Germantown, MD, USA) for calculation of spatiotemporal variables of interest. Paired t-tests were performed for the nonsided variables (BMI, pain, self-reported walking endurance, velocity, cadence, stride length, step width, and FSST) and a separate two-way repeated measures, two-by-two analysis of variance was performed for sided variables of single-stance time and step length. For main effects, post hoc pairwise comparisons were performed to distinguish group differences (Stata; Stata Corporation, College Station, TX, USA) (α = 0.05).
Results
Mean NRS score for pain decreased in all patients from a mean of 4 ± 2 to 1 ± 1 (∆ mean = 3; 95% confidence interval [CI], 1-5; p = 0.038). Before amputation, four of nine patients reported narcotic use, three were using a tricyclic antidepressant for pain control, one patient reported taking over-the-counter pain medication, and three patients reported that they were not using pain medications. After amputation, only one of nine patients was taking narcotics, whereas six patients reported taking no pain medications. Two patients were taking peripheral neuropathy agents, which is part of the amputation pain control protocol at Naval Medical Center San Diego.
Patients’ self-reported walking endurance increased from approximately 1 mile preamputation (1 ± 1 miles) to a mean of 7 ± 8 miles (∆ mean = 6; 95% CI, 0-12; p = 0.003) after amputation. Before the amputation, eight of nine patients reported an inability to run and one patient reported the ability to run only when using a carbon fiber passive-dynamic orthosis. After amputation, six of nine patients reported participation in running, two expressed a desire to run, and one patient reported no interest in running but was biking > 6 miles per workout (Table 3). All patients were participating in some type of higher level activity that they were not able to do before amputation. Patients improved their FSST from 12 ± 10 seconds preamputation to 5 ± 1 seconds (∆ mean = 7; 95% CI, -3 to 18; p = 0.152) postamputation. Before amputation, four of nine patients were using passive-dynamic ankle-foot orthoses for ambulation and three of nine patients were using canes. At the evaluation after amputation, none of the patients required use of an assistive device other than the prosthesis. All nine patients wore their prostheses for a mean of 15 hours a day at the postamputation visit. All prosthetic feet used by the patients were passive carbon fiber, energy storage, and return type (Table 3).
The instrumented gait analysis data showed improvement in velocity, stride length, cadence, and step width between the before- and after-amputation assessments. Velocity increased from 108 ± 16 cm/s to 142 ± 7 cm/s postamputation (∆ mean = 35; 95% CI, 22-47; p < 0.001). Stride length increased from 129 ± 14 cm to 154 ± 8 cm postamputation ((∆ mean = 25; 95% CI, 17-32; p < 0.001). Cadence increased from 101 ± 9 to 111 ± 7 steps per minute (∆ mean = 10; 95% CI, 4-17; p = 0.008) and step width decreased (improved) from 16 ± 3 cm to 12 ± 2 cm postamputation (∆ mean = -4; 95% CI, -6 to -2; p = 0.004) (Table 4). An asymmetric gait pattern was noted both before and after amputation with differences in single-limb stance time. Before amputation, patients spent a smaller proportion of time in stance phase of gait on the involved side (32% ± 3% of the gait cycle) compared with the uninvolved limb (38% ± 4% of the gait cycle; p < 0.001). This asymmetry was still present after amputation, but was not made worse by the increase in walking velocity. Step length improved bilaterally from before to after amputation with the involved limb measuring an increase of 13 cm (p < 0.001) and the uninvolved limb demonstrating an increase of 12 cm (p < 0.001) (Table 5).
Table 4.
Self-selected gait spatiotemporal variables
Table 5.
Sided gait spatiotemporal variables: two-by-two analysis of variance
Discussion
Although limb preservation attempts are often made for military personnel who have sustained severe lower extremity trauma, some patients will undergo a number of procedures and still be left with a painful, poorly functioning extremity. Our small study showed that elective late TTA after attempted limb preservation in this military population may be successful in terms of decreased pain and narcotic use, increased activity level, improved FSST, elimination of the requirement for assistive devices, and improved gait mechanics.
Several limitations should be acknowledged when interpreting the results of this study. Clearly some patients will have a very functional lower extremity after limb preservation attempts and even some who do not may not elect TTA. This population is understandably limited. The first limitation of this study is that of a small sample size. It is a sample of convenience with one of the inclusion criteria being an instrumented gait analysis both preamputation and postamputation. In the future, possible collaborative studies including the other major military medical centers could enhance this cohort. Second, there might be a lack of generalizability to a nonmilitary population. We recognize that the active-duty population is not just unique physically, but has access to specialized care, rehabilitation programs, and support systems that are not readily available to the civilian population. Therefore, the results of this study may not translate well to a civilian trauma population, but do apply in treatment efforts directed to helping service members in their return to duty or an active lifestyle. The Comprehensive Combat and Complex Casualty Care (C5) program at Naval Medical Center San Diego provides ease of access and coordination of services including medical and surgical care, rehabilitation, mental health, and immediate prosthetic fitting and facilitates extensive followup care and is available to all active and retired military members. Translating these data to the general population may be limited to traumatic injuries in a younger or healthy population and not necessarily the dysvascular limbs that are also associated with limb preservation versus amputation. Third, the retrospective nature of this study lends itself to certain inherent limitations, specifically selection bias. The patients in this study all requested and elected for amputation as a result of pain and limitations in functional ability. For example, one patient stated that he could no longer run and play with his children as a result of his painful limb, driving him to seek amputation as a solution. The conversion to amputation from limb preservation is only undertaken after careful consideration on both the patient’s and surgeon’s part. Also, quality-of-life data are missing from this study. These data were not collected on all patients before their amputation so they were not included in this article. Quality-of-life data are now routinely collected on all patients before each gait analysis and will be included in future manuscripts. In addition, there was a lack of a universal trial of a passive-dynamic orthosis for all patients. It is now standard practice at our center to offer all appropriate patients a trial of a passive-dynamic ankle-foot orthosis before late amputation. This type of orthosis was not available until 2011, 3 years after the initial data collection for this study. Finally, mean followup time was only 13 months in this study because several patients relocated out of the area. Gait analysis and overall functional results will need longer term followup to fully assess the effects of late amputation after multiple limb preservation attempts.
After TTA, our patients reported less pain and less need for pain medication. Smith reported results of a study that investigated early versus late amputation by using the Sickness Impact Profile (SIP), looking at the overall disability, which includes physical and psychosocial components as well as return to work, ability to achieve a walking speed of < 4 feet per second, and a visual pain scale. They compared early and late amputation groups and found that the SIP scores were elevated in the late amputation group (worse) and there was a reported return to work rate of only 14% in the late amputation group (Smith D, Castillo R, MacKenzie E; LEAP Study Group. Functional outcomes of patients who have late amputation after trauma is significantly worse than for those who have early amputation. Presented at the Orthopaedic Trauma Association 19th Annual Meeting; October 9-11, 2003; Salt Lake City, UT, USA).
The groups did not have much difference in walking speeds or pain scores, contrary to our data. Again, this could be the result of the nature of our population and the access to rehabilitation services that was and continues to be provided to these patients. Our findings were similar in that only one patient returned to full active duty, but all were wearing their prosthesis for the duration of an average workday.
After undergoing amputation, all of our patients self-reported increased walking endurance and activity level, and none required the use of an assistive device. Similar to the METALS study, our population is unique by virtue of younger age, fewer comorbidities before injury, and motivation to return to vigorous activities [3]. Georgiadis et al. [4] looked at the long-term outcomes and the quality of life in patients with open tibial shaft fractures with severe soft tissue loss who had undergone limb preservation with a free flap versus amputation. The study found that patients with limb preservation took longer to achieve full weightbearing status, were less willing or able to work, considered themselves severely disabled, and had more difficulty with performance of occupational and recreational activities. The successful limb preservation group also had a decrease in motion. In the present study, all patients achieved a high level of functional ability postamputation with the use of their prostheses. As compared with preamputation, walking tolerance increased from a mean of 1 mile to 7 miles. At the postamputation time point, six of nine patients reported the ability to run and two others the desire to run but had not yet mastered the running-specific prosthesis. The ninth patient chose to be a bicyclist and rode his bike 6 miles per day. Two of the patients who had returned to running were participating in half-marathons and triathlons.
The gait analysis demonstrated a mean speed increase of 33 cm/s from pre- to postamputation. At the postamputation time point, the mean walking speed was 142 cm/s, which was considered above the minimum threshold for functional community walking. According to the US Department of Transportation, the walking speed needed to safely cross a street is 120 cm/s [13]. Speed increase was the result of a combination of increased cadence and a bilateral increase in step length. A slight asymmetry in single-limb stance time persisted from pre- to postamputation measurements with greater stance time on the uninvolved limb by 3.3% of the gait cycle. Importantly, the magnitude of the asymmetry was not exacerbated by the walking velocity increase preamputation to postamputation, possibly suggesting the slight deficit was the result of movement patterns learned while walking for 5 ± 3 years with chronic limb pain rather than from the new challenges of walking with a prosthesis. In addition, slight stance time asymmetry is a common gait deficit of healthy, pain-free patients with unilateral TTA [7, 14]. To our knowledge there are no studies that have looked specifically at these gait parameters in this population.
Historically, regardless of the pathway chosen between limb preservation and amputation, severe lower extremity injuries have not had good long-term outcomes. MacKenzie and Bosse [9] discussed the outcomes of the US civilian population at 2- and 7-year followup and found no difference between the amputation and limb preservation groups. However, both groups’ outcomes were reported as poor. Their study also discussed the residual impairment that goes beyond that of the initial injury to include medical complications, pain, posttraumatic stress disorder, autism spectrum disorder, and depression. These secondary conditions greatly influence the patient’s overall quality of life. Although access to social support systems, age, sex, comorbidities, and economic resources are factors that often cannot be changed, others such as self-efficacy can be influenced given the proper resources. Again, the unique design of the C5 program and our specific patient population may be important factors contributing to the outcomes of our study [12].
Our study found that those patients who undergo late TTA after multiple limb preservation attempts have decreased pain, decreased use of narcotic medication, improved activity levels and walking endurance, improved FSST time as well as the ability to wear a prosthesis for most of the day without the use of canes or crutches. Instrumented gait analysis demonstrated increases in walking velocity, cadence, and stride length and decreased step width, which suggests more functional community ambulation. Further studies should compare a cohort of similar patients who had early or immediate TTA and those who have compromised limb preservation but have acquired a carbon fiber passive-dynamic orthosis that allows high-level functional activities without pain. A future study is planned to involve collaboration with other military advanced rehabilitation sites who have collected similar gait analysis data before and after amputation with hopes of adding to the findings of the present study.
Acknowledgments
We thank the orthopaedic surgeons, Scott Helmers, David Dromsky, and Sophia Deben, who were responsible for the orthopaedic care of the patients; the staff of the Gait Analysis Laboratory at Naval Medical Center San Diego who collected these data; and most of all the patients who served this country and have inspired us to advance the medical mission.
Footnotes
Each author certifies that neither he or she, nor any member of his or her immediate family, has funding or commercial associations (consultancies, stock ownership, equity interest, patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article.
All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research®editors and board members are on file with the publication and can be viewed on request.
Clinical Orthopaedics and Related Research® neither advocates nor endorses the use of any treatment, drug, or device. Readers are encouraged to always seek additional information, including FDA approval status, of any drug or device before clinical use.
Each author certifies that his or her institution approved the human protocol for this investigation and that all investigations were conducted in conformity with ethical principles of research.
The views expressed herein are those of the author(s) and do not necessarily reflect the official policy or position of the Department of the Navy, Department of Defense, or the US Government.
References
- 1.Bosse MJ, MacKenzie EJ, Kellam JF, Burgess AR, Webb LX, Swiontkowski MF, Sanders RW, Jones AL, McAndrew MP, Patterson BM, McCarthy ML, Travison TG, Castillo RC. An analysis of outcomes of reconstruction or amputation after leg-threatening injuries. N Engl J Med. 2002;347:1924–1931. [DOI] [PubMed] [Google Scholar]
- 2.Dite W, Temple VA. A clinical test of stepping and change of direction to identify multiple falling older adults. Arch Phys Med Rehabil. 2002;83:1566–1571. [DOI] [PubMed] [Google Scholar]
- 3.Doukas WC, Hayda RA, Frisch M, Anderson RC, Mazurek MT, Ficke JR, Keeling JJ, Pasquina PF, Wain HJ, Carlini AR, MacKenzie EJ. The Military Extremity Trauma Amputation/Limb Salvage (METALS) study. J Bone Joint Surg Am. 2013;95:138–145. [DOI] [PubMed] [Google Scholar]
- 4.Georgiadis GM, Behrens FF, Joyce MJ, Early AS, Simmons AL. Open tibial fractures with severe soft-tissue loss. Limb salvage compared with below-the-knee amputation. J Bone Joint Surg Am. 1993;75:1431–1441. [DOI] [PubMed] [Google Scholar]
- 5.Gwinn DE, Tintle SM, Kumar AR, Andersen RC, Keeling JJ. Blast-induced lower extremity fractures with arterial injury: prevalence and risk factors for amputation after initial limb-preserving treatment. J Orthop Trauma. 2011;25:543–548. [DOI] [PubMed] [Google Scholar]
- 6.Huh J, Stinner DJ, Burns TC, Hsu JR. Infectious complications and soft tissue injury contribute to late amputation after severe lower extremity trauma. J Trauma. 2011;71:S47–S51. [DOI] [PubMed] [Google Scholar]
- 7.Isakov E, Burger H, Krajnik J, Gregoric M, Marincek C. Influence of speed on gait parameters and on symmetry in trans-tibial amputees. Prosthet Orthot Int. 1996;20:153–158. [DOI] [PubMed] [Google Scholar]
- 8.Krueger CA, Rivera JC, Tennent DJ, Sheean AJ, Stinner DJ, Wenke JC. Late amputation may not reduce complications or improve mental health in combat-related, lower extremity limb salvage patients. Injury. 2015;46:1527–1532. [DOI] [PubMed] [Google Scholar]
- 9.MacKenzie EJ, Bosse MJ. Factors influencing outcome following limb-threatening lower limb trauma: lessons learned from the Lower Extremity Assessment Project (LEAP). J Am Acad Orthop Surg. 2006;14:S205–S210. [DOI] [PubMed] [Google Scholar]
- 10.MacKenzie EJ, Bosse MJ, Castillo RC, Smith DG, Webb LX, Kellam JF, Burgess AR, Swiontkowski MF, Sanders RW, Jones AL, McAndrew MP, Patterson BM, Travison TG, McCarthy ML. Functional outcomes following trauma-related lower-extremity amputation. J Bone Joint Surg Am. 2004;86:1636–1645. [DOI] [PubMed] [Google Scholar]
- 11.MacKenzie EJ, Bosse MJ, Kellam JF, Burgess AR, Webb LX, Swiontkowski MF, Sanders RW, Jones AL, McAndrew MP, Patterson TM, McCarthy ML. Characterization of patients with high-energy lower extremity trauma. J Orthop Trauma. 2000;14:455–466. [DOI] [PubMed] [Google Scholar]
- 12.MacKenzie EJ, Morris JA, Jr, Jurkovich GJ, Yasui Y, Cushing BM, Burgess AR, DeLateur BJ, McAndrew MP, Swiontkowski MF. Return to work following injury: the role of economic, social, and job-related factors. Am J Public Health. 1998;88:1630–1637. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13.Manual on Uniform Traffic Control Devices for Streets and Highways. Washington, DC: US Department of Transportation Federal Highway Administration; 2003. [Google Scholar]
- 14.Nolan L, Wit A, Dudziñski K, Lees A, Lake M, Wychowañski M. Adjustments in gait symmetry with walking speed in trans-femoral and trans-tibial amputees. Gait Posture. 2003;17:142–151. [DOI] [PubMed] [Google Scholar]
- 15.Stinner DJ, Burns TC, Kirk KL, Ficke JR. Return to duty rate of amputee soldiers in the current conflicts in Afghanistan and Iraq. J Trauma. 2010;68:1476–1479. [DOI] [PubMed] [Google Scholar]
- 16.Stinner DJ, Burns TC, Kirk KL, Scoville CR, Ficke JR, Hsu JR. Prevalence of late amputations during the current conflicts in Afghanistan and Iraq. Mil Med. 2010;175:1027-1029. [DOI] [PubMed] [Google Scholar]