Influence of Immediate and Delayed Lower-Limb Amputation Compared with Lower-Limb Salvage on Functional and Mental Health Outcomes Post-Rehabilitation in the U.K. Military

Ladlow, Peter MSc; Phillip, Rhodri MSc, FRCP; Coppack, Russell MSc; Etherington, John MSc, FRCP; Bilzon, James PhD; McGuigan, M. Polly PhD; Bennett, Alexander N. PhD, FRCP

Journal of Bone & Joint Surgery - American Volume:
doi: 10.2106/JBJS.15.01210
Scientific Articles
Abstract

Background: Medical practitioners face difficult decisions over whether to amputate or to salvage a lower limb that has undergone trauma. To our knowledge, there has been little evidence reporting the impact of different surgical decisions on functional and mental health outcomes following intensive rehabilitation that might inform decision-making.

Methods: This study is a retrospective, independent-group comparison of rehabilitation outcomes from a U.K. military complex trauma rehabilitation center. There were 100 procedures examined: 36 unilateral amputations (11 immediate-below-the-knee amputations, 15 delayed below-the-knee amputations, and 10 immediate above-the-knee amputations), 43 bilateral amputations, and 21 single-limb salvages (including 13 below-the-knee limb salvages); the patients had a mean age (and standard deviation) of 29 ± 6 years and a mean New Injury Severity Score of 34 ± 15 points. The outcome measures at completion of rehabilitation included a 6-minute walk test (6MWT), Defence Medical Rehabilitation Centre mobility and activities of daily living scores, screening for depression (Patient Health Questionnaire [PHQ-9]) and general anxiety disorder (General Anxiety Disorder 7-item scale [GAD-7]), mental health support, and pain scores.

Results: On completion of their rehabilitation, the unilateral amputation group walked significantly farther in 6 minutes (564 ± 92 m) than the limb-salvage group (483 ± 108 m; p < 0.05) and the bilateral amputation group (409 ± 106 m; p < 0.001). The delayed below-the-knee amputation group (595 ± 89 m) walked significantly farther than the group with limb salvage below the knee (472 ± 110 m; p < 0.05), and there was no significant difference between the group with delayed below-the-knee amputation and the group with immediate below-the-knee amputation (598 ± 63 m; p > 0.05). The limb-salvage group was less capable of running independently compared with all amputee groups. No significant differences (p > 0.05) were reported in mean mental health outcomes between the below-the-knee injury groups, and depression and anxiety scores were comparable with population norms. At discharge, 97% of all patients were able to control their pain.

Conclusions: After completing a U.K. military interdisciplinary rehabilitation program, the unilateral amputation group demonstrated a significant functional advantage over the limb-salvage and bilateral amputation groups. We found that patients electing for delayed amputation below the knee after attempted limb salvage achieved superior functional gains in mobility compared with patients who underwent limb salvage below the knee and experienced no functional disadvantage compared with patients who underwent immediate amputation. The mental health outcomes were comparable with general population norms, optimizing the prospect of full integration back into society.

Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Author Information

1Academic Department of Military Rehabilitation, Defence Medical Rehabilitation Centre (DMRC) Headley Court, Surrey, United Kingdom

2Department for Health, University of Bath, Bath, United Kingdom

E-mail address for A.N. Bennett: alexander.n.bennett@btinternet.com

Article Outline

Difficult decisions face medical practitioners and patients alike regarding amputation, and there is a need for more objective evidence to inform decision-making. To our knowledge, there is currently little evidence to suggest whether different surgical decisions lead to different functional outcomes. Recently, functional outcomes in amputees were reported to be comparable with those in the age-matched general population1. This raises the question of whether it is better to amputate or to attempt to salvage a limb in patients experiencing severe trauma. Doukas et al.2 published self-reported outcomes of amputation compared with limb salvage following major lower-extremity trauma within the U.S. military. They found that patients who had undergone unilateral or bilateral amputation had significantly better functional outcomes than those whose limbs had been salvaged. No differences in the probability of screening positive for depression or of having pain interference were identified.

The U.K. and U.S. military deliver different rehabilitation pathways to their severely injured service personnel3. The primary aims of this study were to examine mental health and markers of functional outcome in lower-limb amputees and patients who underwent limb salvage following intensive residential rehabilitation in a U.K. military complex trauma center. We compared these outcomes in patients who underwent immediate unilateral amputation with outcomes in patients who underwent delayed unilateral amputation and in patients who underwent unilateral lower-limb salvage. We hypothesized that amputees would achieve superior functional outcomes compared with patients who underwent limb salvage, and both groups of patients would experience similar mental health outcomes.

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Materials and Methods

Overview and Data Sources

A retrospective analysis of the functional and mental health outcomes on completion of rehabilitation was undertaken in a military cohort of patients who had undergone posttraumatic lower-limb salvage or lower-limb amputation. All patients who had undergone unilateral amputation, bilateral amputation, or limb salvage discharged from January 2013 to January 2015 were included in the analysis. The majority (90%) of patients were injured while on operational deployment to Iraq or Afghanistan, and the remaining patients were injured via road traffic accidents or training exercises. In a previous study, we extensively described the Defence Medical Rehabilitation Centre (DMRC) complex-trauma rehabilitation pathway1. Lower-limb amputees were classified as any patient with an amputation level at the ankle or above. Only patients who had undergone digital and foot amputations were excluded from the analysis. Patients in the limb-salvage group were identified in accordance with the injury inclusion criteria used in the study of injured U.S. military personnel2; patients who underwent unilateral amputation did not have any injuries defined as limb salvage to the uninvolved lower limb, and limb-salvage groups were identified as patients having injuries to one lower limb only. Permission to access anonymized clinical data was granted by the local Caldicott Guardian (person responsible for protecting the patient confidentiality and service user information and for enabling appropriate information sharing), and ethical approval to use these data for research purposes was granted by the Research Ethics Approval Committee for Health (REACH), Department for Health, University of Bath.

Injury severity was collected at the time of injury, was recorded by the U.K. Joint Theatre Trauma Registry database, and was defined by the New Injury Severity Score. “Major trauma” has been defined as a New Injury Severity Score of >15 points, and a score of 16 is associated with a mortality rate of 10%4. The New Injury Severity Score measures injury severity from 1 to 75 points, with higher numbers indicating greater severity of injury.

Patient demographic characteristics and length of rehabilitation were recorded. Length of rehabilitation was defined by the number of approximately 4-week inpatient admissions and the number of months from first to last admission. Predicted body mass and body mass index (BMI) were calculated according to methods outlined by Osterkamp5. Functional and mental health outcome measures were recorded at the time of completion of the rehabilitation pathway. All data were extracted from the Defence Medical Information Compatibility Programme (DMICP) or from medical notes.

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Functional Outcome Measures

The 6-minute walk test (6MWT)6 is an internationally recognized, validated outcome measure, used to assess function in a range of conditions. The test was performed indoors on a marked 20-m flat surface and patients were instructed to walk back and forth around a cone as many times as possible in 6 minutes. In addition, two DMRC-developed outcome tools were completed by clinicians who assessed the level of mobility and the ability to perform activities of daily living independently (Table I).

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Mental Health Outcomes Measures

The General Anxiety Disorder 7-item scale (GAD-7)7 and the Patient Health Questionnaire (PHQ-9)8 are two validated self-reported questionnaires; PHQ-9 is used to define the severity of depression and GAD-7 is used to define general anxiety disorder. Both report a simple diagnostic grading scale of none or minimal to severe. In addition, two other DMRC-developed outcome tools were completed by clinicians to assess the requirement for mental health support and the assessment of ongoing pain (Table I).

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Definition of Patient Groups

The patients were grouped according to unilateral or bilateral lower-limb amputations or limb salvage. Subanalyses were then performed on the unilateral amputation group with patients defined as undergoing immediate below-the-knee amputation, delayed below-the-knee amputation, or immediate above-the-knee amputation. Immediate below-the-knee amputation was defined as amputation within 5 days of trauma; delayed below-the-knee amputation was defined as amputation up to 3 months after the injury or trauma in accordance with the precedent set by the Lower Extremity Assessment Project (LEAP) Study Group9.

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Data Analysis

All data were checked for normality of distribution using the Kolmogorov-Smirnov test and tests for skewness and kurtosis. A one-way analysis of variance (ANOVA) was used to determine if there were significant main effects of the outcome of injury on injury severity, length of rehabilitation, and the functional and mental health outcome measures. Post hoc analyses, using the least-significant-difference pairwise comparison test, were performed to determine differences between groups. All statistical analyses were performed using SPSS Statistics (version 21; IBM). The level of significance was set a priori as p < 0.05.

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Results

Patient Demographic Characteristics

One hundred patients with a mean age (and standard deviation) of 29 ± 6 years were evaluated at the completion of their rehabilitation pathway (Table II): 36 patients who underwent unilateral amputation (11 immediate below-the-knee amputations, 15 delayed below-the-knee amputations, and 10 immediate above-the-knee amputations), 43 patients who underwent bilateral amputation, and 21 patients who underwent limb salvage (including 13 who underwent limb salvage below the knee). There was a significant main effect of group on age (F = 3.880, p = 0.024), with a significantly older age in the unilateral amputation group compared with the bilateral amputation group (p = 0.007). The mean time interval between the time of injury and amputation in the delayed below-the-knee amputation group was 10 ± 11 months. During the time period prior to amputation, the DMRC treated 10 of these 15 patients with a mean of 3 ± 3 admissions. The leading injury characteristic in this group was bone fractures (n = 11 [73%]), followed by nerve damage with no associated fracture (n = 3 [20%]). Three (20%) of these 15 patients also experienced extensive soft-tissue or vascular trauma from blast fragments to the lower limb. All patients who had undergone delayed below-the-knee amputation had elective amputation due to chronic pain and/or a loss of lower-limb muscle function.

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Injury Severity at the Time of Injury

The type of injury had a significant main effect on the New Injury Severity Score (n = 77) (F = 48.597, p < 0.001). The mean New Injury Severity Score for the total cohort was 34 ± 15 points, with the bilateral amputation group experiencing injuries of significantly greater severity than the unilateral amputation and limb-salvage groups (p < 0.001), with no significant difference (p > 0.05) between the unilateral amputation group and the limb-salvage group (Table III). Subanalysis of the unilateral amputation and limb-salvage groups showed that patients who underwent immediate below-the-knee amputation and immediate above-the-knee amputation experienced greater severity of injury than patients who underwent delayed below-the-knee amputation or those who underwent limb salvage below the knee. Table IV defines the injury characteristics of the limb-salvage groups.

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Length of Rehabilitation

The type of injury had a significant effect on the length of rehabilitation (F = 5.995, p = 0.004) and the number of 4-week admission at the DMRC (F = 23.549, p < 0.001) (Table V). The limb-salvage group required a significantly shorter length of rehabilitation than the unilateral amputation group (p = 0.009) and the bilateral amputation group (p = 0.001). Subanalysis of the unilateral amputation and limb-salvage groups revealed that immediate below-the-knee amputation and immediate above-the-knee amputation required a significantly greater number of months of rehabilitation than delayed below-the-knee amputation and limb salvage below the knee (p < 0.05). There were no significant differences between limb salvage below the knee and delayed below-the-knee amputation groups (p > 0.05). The bilateral amputation group required a significantly greater number of 4-week admissions compared with the unilateral amputation and limb-salvage groups (p < 0.001). Subanalysis of the unilateral amputation and limb-salvage groups revealed no significant differences in the number of admissions between injury levels (p > 0.05).

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Functional Outcomes

The type of injury had a significant effect on the distances that patients could walk in 6 minutes (F = 19.655, p < 0.001) as measured with the 6MWT (Table VI). At the completion of rehabilitation, patients who had undergone unilateral amputation (n = 35) could walk significantly farther than patients who had undergone limb salvage (n = 20, p = 0.006) and those who had undergone bilateral amputation (n = 35, p < 0.001). Patients who had undergone limb salvage could also walk significantly farther than those who had undergone bilateral amputation (p = 0.012). Subanalysis of the unilateral amputation and limb-salvage groups reveal that patients in the immediate below-the-knee amputation and delayed below-the-knee amputation groups (n = 15) could walk significantly farther than the patients who had undergone limb salvage below the knee and those who had undergone immediate above-the-knee amputation (p < 0.05). No significant difference was found between patients who had undergone immediate below-the-knee amputation and those who had undergone delayed below-the-knee amputation.

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Mental Health Outcomes

There were no effects of the type of injury on depression symptoms (PHQ-9) or generalized anxiety disorder (GAD-7) in all groups (p > 0.05) (Table VI). The total mean scores for these two mental health outcomes were comparable with reporting of <5 or “no symptoms.”10,11

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DMRC Mental Health Support and Pain

A similar proportion of patients in the unilateral amputation and limb-salvage groups required mental health support during their last admission at DMRC, and both groups reported twice the prevalence of the bilateral amputation group (Table VI). A greater proportion of patients in the limb-salvage group reported uncontrolled pain (14%) during their last admission compared with the unilateral amputation group (3%) and the bilateral amputation group (0%). The most favorable outcome (no pain) was reported the most in the amputee groups. The prevalence of patients who had undergone immediate below-the-knee amputation (36%) and those who had undergone delayed below-the-knee amputation (40%) reporting no pain was twice that of the patients who had undergone limb salvage below the knee (15%). At last admission, 97% of the total cohort was able to control their pain.

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Discussion

To our knowledge, this is the first study to compare the functional and mental health outcomes of U.K. military lower-limb amputees with those of patients who have undergone lower-limb salvage. Also, to our knowledge, this is the first time that the rehabilitation outcomes of attempted limb-salvage resulting in delayed below-the-knee amputation have been reported in the published literature.

The unilateral amputation group achieved better functional outcomes after intensive rehabilitation compared with the limb-salvage group, with no significant difference in mental health outcome reported among all groups. Importantly, patients electing for delayed amputation after attempted limb-salvage treatment and rehabilitation achieved superior functional gains in mobility compared with patients who had prolonged limb salvage, and they had no functional disadvantage compared with patients who had undergone immediate below-the-knee amputation. This is of particular clinical importance to the surgeon, medical consultant, and patient making life-changing decisions after traumatic injury, especially when an intensive rehabilitation program and advanced prosthetics are provided post-injury.

After completing their military rehabilitation pathway, 86% of patients in the unilateral amputation group, 33% of patients in the bilateral amputation group, and 70% of patients in the limb-salvage group were able to walk distances in the 6MWT that were comparable with those of age-matched healthy adults (459 to 738 m)12. Doukas et al.2 found participants with unilateral or bilateral amputation had significantly better Short Musculoskeletal Functional Assessment (SMFA) outcomes than those whose limbs had been salvaged. Although we did not use this specific outcome measure, we did find similarities between the U.S. and U.K. military in functional outcomes. Our unilateral amputation group achieved greater mobility outcomes compared with the limb-salvage group in the 6MWT and independent running and walking mobility tasks. Doukas et al. reported that amputees were 2.6 times more likely to engage in vigorous activity than their limb-salvage group. We also found a greater prevalence of high activity levels (running independently) in our amputees (50% in the unilateral amputation group and 14% in the bilateral amputation group) compared with the limb-salvage group (5%). We found that the level of amputation (preservation of the knee joint) had a significant effect on the mean 6MWT, with both patients who had undergone immediate below-the-knee amputation and patients who had undergone delayed below-the-knee amputation able to walk significantly farther (>115 m) than those who had undergone immediate above-the-knee amputation. Despite using a different 6MWT protocol, similar mean differences (>115 m) between below-the-knee amputation (661 ± 87 m) and above-the-knee amputation (542 ± 67 m) were reported in U.S. military13. The increased ability of patients who had undergone limb salvage below the knee to perform activities of daily living independently compared with patients who had undergone immediate below-the-knee amputation, immediate above-the-knee amputation, or bilateral amputation is likely a reflection of the difference in injury severity. Although not reported, finger amputations are common in our blast-injured amputees, thus causing difficulty for some patients in performing some activities of daily living. Therefore, when making comparisons based on level and timing of lower-limb amputation or injury, the 6MWT and DMRC mobility measures could be considered a more relevant or comparable measure of function.

The unilateral amputation, bilateral amputation, and limb-salvage mental health outcomes reported closely reflect the general population norms of major anxiety rates (GAD-7)10 from 1.3% to 6% and major depression rates (PHQ-9)11 from 1.6% to 6.7%. The U.K. military mental health findings support those found in U.S. military personnel2 where no differences were found between limb loss and limb salvage. The civilian LEAP study14 performed a 2-year follow-up on patients treated at Level-1 trauma centers for severe lower-limb injury. They found that 37.6% of patients reported “moderate to severe” depression, 19% reported “severe” depression, 29.4% reported “moderate to severe” anxiety, and 14.4% reported “severe” anxiety. Both the studies by Doukas et al.2 and McCarthy et al.14 showed a similar prevalence of depressive symptoms. It is important to note that the outcome measures used to define depression and anxiety in those studies are different compared with our study. Possible explanations for the different mental health outcomes between U.S. and U.K. military trauma casualties have recently been summarized1. Explanations for why the psychological profiles appear unaffected by major injury are varied and are likely to be patient-specific. Horgan and MacLachlan15 suggested that an acceptance of a changed body image over time, higher levels of active coping, an optimistic personality disposition, increased levels of social support, greater satisfaction with the prosthesis, and decreased pain levels all contribute to better mental health outcomes over time. A likely explanation for the lack of any significant differences in mean mental health scores reported between the different U.K. military injury groups is that all patients with complex trauma are offered the same mental health support services throughout the rehabilitation process. This support is individually tailored to the patient’s needs and (if required) is provided throughout their rehabilitation pathway. Despite the similarities in mean scores, there was a greater prevalence of major depressive and anxiety symptoms in the groups that had undergone delayed below-the-knee amputation or limb salvage below the knee compared with groups that had undergone immediate below-the-knee amputation, immediate above-the-knee amputation, or bilateral amputation. This could be due to all groups that had undergone immediate below-the-knee amputation, immediate above-the-knee amputation, or bilateral amputation being able to control their pain by the last admission, or, as a consequence of surviving high severities of trauma, having had a greater appreciation for being alive. The difference in mental health status between patients who had undergone immediate below-the-knee amputation and those who had undergone delayed below-the-knee amputation might be explained by the prolonged pain and/or dysfunction that led to elective amputation in the patients who had undergone delayed below-the-knee amputation. Krueger et al.16 found that the mental health of patients who underwent limb salvage and then delayed amputation did not change postoperatively. However, we have not reported pre-amputation mental health outcomes to confirm this.

To our knowledge, there were no objective functional data available in civilian cohorts with which direct comparisons with our military cohort could have been made. However, both our U.K. military and the U.S. military2 key findings are contrary to the results of a meta-analysis on civilian patients who have undergone amputation or limb salvage17. That meta-analysis revealed lower-limb salvage to be more acceptable psychologically to patients with severe lower-limb trauma compared with amputation, and functional outcomes were similar between these groups. Our results have demonstrated a functional advantage in the unilateral amputation groups over the limb-salvage group. One explanation for this is the recent advances in prosthetic design and technology to which U.K. military amputees have greater access compared with civilian cohorts. Large differences in the access to rehabilitation services post-injury are another factor, as few countries have the resources to provide civilian amputees with such intensive post-injury or amputation rehabilitation services. At the DMRC, patients who have undergone limb salvage or amputation gain access to the same clinicians and quantity of rehabilitation and would receive an optimal prosthetic or orthotic intervention if required. The notable differences between these two groups are that amputees can weight-bear as soon as there is sufficient wound-healing, whereas patients who undergo limb salvage may need to wait several months (for example, time for bone-healing). There may also be additional pain interference in the lower limb of patients who undergo limb salvage that is no longer present in an amputated limb. There is now an urgent demand for advances in technology within the U.K. military to enable patients who undergo limb salvage to function at higher levels of mobility.

The outcomes presented in this study represent a cross-sectional description of the rehabilitation pathway at last admission in a relatively small critical cohort of patients and do not reflect the inevitable fluctuations that occur in functional and mental health outcomes throughout a prolonged period of rehabilitation. We are unable to evaluate the effect that 10 months (three admissions) of pre-amputation rehabilitation had on the outcomes demonstrated in the group that underwent delayed below-the-knee amputation compared with the groups that underwent immediate below-the-knee amputation or limb salvage below the knee. However, because of chronic pain or lack of muscle function, these patients would have reached a plateau in their rehabilitation and amputation was required to achieve future functional improvements. We recognize that this pre-amputation rehabilitation could have influenced the significant differences reported for patients who underwent limb salvage below the knee. As a patient group, patients who have undergone delayed amputation below the knee have previously reported higher numbers of revision surgical procedures, rates of infectious complications, and non-healing wounds compared with patients who have undergone limb salvage or immediate amputation18,19 and no change to their mental well-being from pre-amputation to post-amputation16. There are multiple long-term health consequences associated with limb loss20,21 that should be considered.

As a population group, military personnel are predominantly male, are 20 to 40 years of age, and have undergone intense physical training in the course of their career. The types of injuries in our patients who required limb salvage below the knee and delayed below-the-knee amputation are not dissimilar to what might be expected in civilian-based road traffic accidents (e.g., on a motorcycle) and some adventure sports. As a group, they are often defined by their physical attributes and are motivated to get the most from their physical function yet are often most affected by the physical loss of their injury. We believe that the main messages from this study would be of benefit to surgeons and medical clinicians working with patients of similar age and personality dispositions.

In conclusion, following intensive multidisciplinary rehabilitation, the unilateral amputation group demonstrated a significant functional advantage over the limb-salvage and bilateral amputation groups. We found that patients electing for delayed amputation achieve superior functional gains in mobility compared with patients who undergo prolonged limb salvage. Importantly, patients who undergo delayed unilateral amputation perform similarly to patients who undergo immediate unilateral amputation, and therefore there is no detriment to the patient in attempting to salvage a limb if it is medically and surgically viable. However, at this time, to our knowledge, there are insufficient data to support best-practice recommendations. Our findings demonstrate that patients with severely injured lower limbs who follow the U.K. military rehabilitation pathway report no significant differences in mental health well-being and are comparable with general population norms, optimizing the prospect of full integration back into society.

NOTE: The authors thank the Clinical Information Exploitation Team and Defence Statistics Health for collecting, collating, and identifying the appropriate data for the New Injury Severity Scores used in this study.

Investigation performed at the Defence Medical Rehabilitation Centre (DMRC) Headley Court, Surrey, United Kingdom

Disclosure: There was no funding source. The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article.

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