Predictors for the Healing of Transmetatarsal Amputations: Retrospective Study of 91 Amputations

Above-ankle Reamputation and Mortality following Transmetatarsal Amputation in Diabetic and Nondiabetic Peripheral Artery Disease

The risk of above-ankle reamputation following a transmetatarsal amputation is around 30%. Patient selection may be crucial to achieve good outcomes, and to avoid futile operations and suffering. We are aware of no previous comparison between the two largest patient groups that undergo lower extremity amputations: patients with diabetes, and patients with non-diabetic peripheral artery disease. Patients with diabetes or nondiabetic peripheral artery disease who had undergone a transmetatarsal amputation from 2004 to 2018 at our institution were included. Patient characteristics and perioperative details were analyzed retrospectively. Subjects with diabetes were compared with subjects with nondiabetic peripheral artery disease regarding above-ankle reamputation, reamputation level, and mortality. Five-hundred-and-sixty transmetatarsal amputations in 513 subjects were included. The majority of transmetatarsal amputations (86%) occurred in diabetic subjects. Subjects with non-diabetic PAD had a higher risk of above-ankle reamputation (p = .008), and death (p < .001). At the time of data collection, only multiple-ray amputation (vs. single-ray) was an independent risk factor for above-ankle reamputation. Only age, medical comorbidity in general, and chronic heart failure were independent risk factors of death. To our knowledge, this study is the first to report marked differences in above-ankle reamputation rates and mortality following transmetatarsal amputation, comparing diabetics with non-diabetic patients with peripheral artery disease. However, the differences may be attributed to non-diabetics being older, having more medical comorbidities, and having more advanced foot ulcers at the time of transmetatarsal amputation. In patients exhibiting several of these risk factors, transmetatarsal amputation may be futile.

Reamputation prevalence after minor feet amputations in patients with diabetic foot, a cross sectional study

INTRODUCTION

Reported prevalence for reamputation in diabetic foot is diverse, risk factors are not clear for minor amputations. This study aims to determine the prevalence for reamputation in diabetic foot from minor amputations and to evaluate associated factors for such outcome.

METHODS

Cross sectional study developed in 2hospitals. Patients hospitalized for diabetic foot ulcer requiring a minor amputation were included. A descriptive analysis of all variables is presented, as well as prevalence ratios (PR) and a multivariate logistic regression.

RESULTS

The prevalence was of 48% for 15 years. Toes were the most frequent minor amputation that required reamputation and above the knee amputation was the most frequent reamputation level (45%). Variables whose PR was associated to reamputation risk were: smoking history (PR 1.32, CI 95%: 1.02-1.67, P=0.03), vascular occlusion in doppler (PR 1.47, CI 95%: 1.11-1.73, P=0.01), revascularization (PR 1.73, CI 95%: 1.31-2.14, P=0.00002), Wagner> 3 (PR 1.75, CI 95%: 1.16-1.84, P=0.01) and leucocytosis> 11,000 (PR 1.39, CI 95%: 1.07-1.68, P=0.01). Leucocytosis> 11,000, Wagner> 3, vascular occlusion in doppler and revascularization were the variables that best predicted the outcome. Furthermore, leucocytosis was the best variable for predicting reamputation (OR 2.4, CI 95%: 1.1-5.6, P=0.04).

CONCLUSIONS

Reamputation prevalence was 48%. The toes were the minor amputation more frequently requiring reamputation and above the knee was the most frequent reamputation level. Risk for reamputation was associated with variables related to vascular compromise and infection.

Healing rates and outcomes following closed transmetatarsal amputations: A systematic review and random effects meta-analysis of proportions

Transmetatarsal amputation (TMA) is a common surgical procedure for addressing severe forefoot pathologies, such as peripheral vascular disease and diabetic foot infections. Variability in research methodologies and findings within the existing literature has hindered a comprehensive understanding of healing rates and complications following TMA. This meta-analysis and systematic review aims to consolidate available evidence, synthesising data from multiple studies to assess healing rates and complications associated with closed TMA procedures. Following Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, a systematic search of Medline, Embase, and Cochrane databases was conducted for articles published from January 1st, 1988, to June 1st, 2023. Inclusion criteria comprised studies reporting healing rates in non-traumatic transmetatarsal amputation patients with more than 10 participants, excluding open TMAs. Two independent reviewers selected relevant studies, with disagreements resolved through discussion. Data extracted from eligible studies included patient demographics, healing rates, complications, and study quality. Among 22 studies encompassing 1569 transmetatarsal amputations, the pooled healing rate was 67.3%. Major amputation rates ranged from 0% to 55.6%, with a random-effects pooled rate of 23.9%. Revision rates varied from 0% to 36.4%, resulting in a pooled rate of 14.8%. 30-day mortality ranged from 0% to 9%, with a fixed-effects pooled rate of 2.6%. Post-operative infection rates ranged from 3.0% to 30.7%, yielding a random-effects pooled rate of 16.7%. Dehiscence rates ranged from 1.7% to 60.0%, resulting in a random-effects pooled rate of 28.8%. Future studies should aim for standardised reporting and assess the physiological and treatment factors influencing healing and complications.

New and Recurrent Ulcerations after Free Tissue Transfer with Partial Bony Resection in Chronic Foot Wounds within a Comorbid Population

BACKGROUND

Chronic foot wounds often require bony resection; however, altering the tripod of the foot carries a risk of new ulcer development nearing 70%. Resulting defects often require free tissue transfer (FTT) reconstruction; outcomes data for various bony resection and FTT options may guide clinical decision-making regarding bone and soft-tissue management. The authors hypothesized that alteration of the bony tripod will increase risk of new lesion development after FTT reconstruction.

METHODS

A single-center retrospective cohort analysis of patients undergoing FTT from 2011 through 2019 with bony resection and soft-tissue defects of the foot was performed. Data collected included demographics, comorbidities, wound locations, and FTT characteristics. Primary outcomes were recurrent lesion (RL) and new lesion (NL) development. Multivariate logistic regression and Cox hazards regression were used to produce adjusted odds ratios and hazard ratios.

RESULTS

Sixty-four patients (mean age, 55.9 years) who underwent bony resection and FTT were included. Mean Charlson Comorbidity Index was 4.1 (SD 2.0), and median follow-up was 14.6 months (range, 7.5 to 34.6 months). Wounds developed after FTT in 42 (67.1%) (RL, 39.1%; NL, 40.6%). Median time to NL development was 3.7 months (range, 0.47 to 9.1 months). First-metatarsal defect (OR, 4.8; 95% CI, 1.5 to 15.7) and flap with cutaneous component (OR, 0.24; 95% CI, 0.07 to 0.8) increased and decreased odds of NL development, respectively.

CONCLUSIONS

First-metatarsal defects significantly increase NL risk after FTT. The majority of ulcerations heal with minor procedures but require long-term follow-up. Soft-tissue reconstruction with FTT achieves success in the short term, but NL and RL occur at high rates in the months to years after initial healing.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, III.

Risk factors for reamputation in patients with diabetic foot: A case-control study

BACKGROUND

Reamputation as a complication of diabetic foot ulcers presents a high economic burden and represents a therapeutic failure. It is paramount to identify as early as possible patients in whom a minor amputation may not be the best option. The purpose of this investigation was to do a case-controlled study to determine risk factors associated with re-amputation in patients with DFU (diabetic foot ulcers) at two University Hospitals.

METHODS

Multicentric, observational, retrospective, case-control study from clinical records of 2 university hospitals. Our study included 420 patients, with 171 cases (re-amputations), and 249 controls. We performed a multivariate logistic regression analysis and time-to-event survival analysis to identify re-amputation risk factors.

RESULTS

Statistically significant risk factors were artery history of tobacco use (p = 0.001); male sex (p = 0.048); arterial occlusion in Doppler ultrasound (p = 0.001); percentage of stenosis in arterial ultrasound >50 % (p = 0.053); requirement of vascular intervention (p = 0.01); and microvascular involvement in photoplethysmography (p = 0.033). The most parsimonious regression model suggests that history of tobacco use, male sex, arterial occlusion in ultrasound, and percentage of stenosis in arterial ultrasound >50 % remained statistically significant. The survival analysis identified earlier amputations in patients with larger occlusion in arterial ultrasound, high leukocyte count, and elevated ESR.

CONCLUSION

Direct and surrogate outcomes in patients with diabetic foot ulcers identify vascular involvement as an important risk factor for reamputation.

LEVEL OF EVIDENCE

III.

Risk Factors for a Failed Transmetatarsal Amputation in Patients with Diabetes

BACKGROUND

Transmetatarsal amputation (TMA) is a well-recognized limb-salvage procedure, often indicated for the treatment of diabetic foot infections. Currently, there is no widespread agreement in the literature with regard to the factors associated with failure of TMA. This study aimed to define risk factors for the failure of TMA, defined as below-the-knee or above-the-knee amputation, in patients with diabetes.

METHODS

This retrospective cohort study included 341 patients who underwent primary TMA. Patients who had a revision to a higher level (the failed TMA group) were compared with those who did not have failure of the initial amputation (the successful TMA group).

RESULTS

This study showed a higher frequency of renal impairment, defined as a high creatinine level and/or a previous kidney transplant or need for dialysis, in the failed TMA group (p = 0.002 for both). Furthermore, a Charlson Comorbidity Index (CCI) threshold value of 7.5 was identified as the optimal predictive value for failure of TMA (p = 0.002), and patients with a CCI of >7.5 had a median time of 1.13 months until the initial amputation failed.

CONCLUSIONS

TMA is associated with a high risk of revision. CCI may be used as a preoperative selection criterion, as 71.8% of patients with a CCI of >7.5 had failure of the TMA.

LEVEL OF EVIDENCE

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

Transmetatarsal amputations in patients with diabetes mellitus: A contemporary analysis from an academic tertiary referral centre in a developing community

Transmetatarsal amputation (TMA) involves the surgical removal of the distal portion of metatarsals in the foot. It aims to maintain weight-bearing and independent ambulation while eliminating the risk of spreading soft tissue infection or gangrene. This study aimed to explore the risk factors and surgical outcomes of TMA in patients with diabetes at an academic tertiary referral center in Jordan. Medical records of all patients with diabetes mellitus who underwent TMA at King Abdullah University Hospital, Jordan, between January 2017 and January 2019 were retrieved. Patient characteristics along with clinical and laboratory findings were analyzed retrospectively. Pearson’s chi-square test of association, Student’s t-test, and multivariate regression analysis were used to identify and assess the relationships between patient findings and TMA outcome. The study cohort comprised 81 patients with diabetes who underwent TMA. Of these, 41 (50.6%) patients achieved complete healing. Most of the patients were insulin-dependent (85.2%). Approximately half of the patients (45.7%) had severe ankle-brachial index (ABI). Thirty patients (37.1%) had previous revascularization attempts. The presence of peripheral arterial disease (P<0.05) exclusively predicted poor outcomes among the associated comorbidities. Indications for TMA included infection, ischemia, or both. The presence of severe ABI (≤0.4, P<0.01) and a previous revascularization attempt (P<0.05) were associated with unfavorable outcomes of TMA. Multivariate analysis that included all demographic, clinical, and laboratory variables in the model revealed that insulin-dependent diabetes, low albumin level (< 33 g/L), high C-reactive protein level (> 150 mg/L), and low score of Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC, <6) were the main factors associated with poor TMA outcomes. TMA is an effective technique for the management of diabetic foot infection or ischemic necrosis. However, attention should be paid to certain important factors such as insulin dependence, serum albumin level, and LRINEC score, which may influence the patient’s outcome.

The Effect of Remnant Metatarsal Parabola Structure on Transmetatarsal Amputation Primary Healing and Durability

Although generally considered to be both a durable and functional procedure for limb preservation, the transmetatarsal amputation (TMA) has high rates of complication, failure, revisional operation, and progression to more proximal amputation. The objective of this investigation was to determine the effect of remnant metatarsal parabola structure on healing outcomes following TMA. A retrospective chart review was performed of subjects undergoing a complete TMA with primary closure. We considered 4 patterns of remnant metatarsal parabola structure. TMA pattern type 1 was a normal parabola with the remnant second metatarsal extending furthest distally and slightly longer than the remnant first and third metatarsals with a gradual lateral taper. TMA pattern type 2 was the first metatarsal remnant extending furthest distally with a gradual lateral taper. TMA pattern type 3 was a relatively long fifth metatarsal remnant without the presence of a gradual lateral taper. And TMA pattern type 4 was a relatively short first metatarsal remnant with a relatively long second metatarsal with a gradual lateral taper. Seventy-three transmetatarsal amputations in 73 subjects met selection criteria. Thirty-nine (53.4%) amputations healed primarily at 90 days. No statistically significant differences were observed between groups with respect to the 90-day primary healing rate (p = .571) or 1-year ambulation rate without wound recurrence or reoperation (p = .811). These results might indicate that the remnant metatarsal structure does not have an effect on transmetatarsal amputation outcome. It is our hope that these results add to the body of knowledge and lead to further investigations into outcomes of limb preservation surgical interventions.

Functional and Patient-reported Outcomes following Transmetatarsal Amputation in High-risk Limb Salvage Patients

Background

Transmetatarsal amputation (TMA) is performed in patients with nonhealing wounds of the forefoot. Compared with below-knee amputations, healing after TMA is less reliable, and often leads to subsequent higher-level amputation. The aim of this study was to evaluate the functional and patient-reported outcomes of TMA.

Methods

A retrospective review of patients who underwent TMA from 2013 to 2021 at our limb-salvage center was conducted. Primary outcomes included postoperative complications, secondary proximal lower extremity amputation, ambulatory status, and mortality. Univariate and multivariate analyses were performed to evaluate independent risk factors for higher-level amputation after TMA. Patient-reported outcome measures for functionality and pain were also obtained.

Results

A total of 146 patients were identified. TMA success was achieved in 105 patients (72%), and 41 patients (28%) required higher-level amputation (Lisfranc: 31.7%, Chopart: 22.0%, below-knee amputations: 43.9%). There was a higher incidence of postoperative infection in patients who subsequently required proximal amputation (39.0 versus 9.5%, P < 0.001). At mean follow-up duration of 23.2 months (range, 0.7-97.6 months), limb salvage was achieved in 128 patients (87.7%) and 83% of patients (n = 121) were ambulatory. Patient-reported outcomes for functionality corresponded to a mean maximal function of 58.9%. Pain survey revealed that TMA failure patients had a significantly higher pain rating compared with TMA success patients (P = 0.016).

Conclusions

TMA healing remains variable, and many patients will eventually require a secondary proximal amputation. Multi-institutional studies are warranted to identify perioperative risk factors for higher-level amputation and to further evaluate patient-reported outcomes.

Avoiding the Deep Plantar Arterial Arch in Transmetatarsal Amputations: A Cadaver Study

BACKGROUND

The deep plantar arterial arch (DPAA) is formed by an anastomosis between the deep plantar artery and the lateral plantar artery. The potential risk of injury to the DPAA is concerning when performing transmetatarsal amputations, and care must be taken to preserve the anatomy. We sought to determine the positional anatomy of the DPAA based on anatomical landmarks that could be easily identified and palpated during transmetatarsal amputation.

METHODS

In an effort to improve our understanding of the positional relationship of the DPAA to the distal metatarsal parabola, dissections were performed on 45 cadaveric feet to measure the location of the DPAA with respect to the distal metatarsal epiphyses. Images of the dissected specimens were digitally acquired and saved for measurement using in-house-written software. The mean, SD, SEM, and 95% confidence interval were calculated for all of the measurement parameters and are reported on pooled data and by sex. An independent-samples t test was used to assess for sex differences. Interrater reliability of the measurements was estimated using the intraclass correlation coefficient.

RESULTS

The origin of the DPAA was located a mean ± SD of 35.6 ± 3.9 mm (95% confidence interval, 34.5-36.8 mm) proximal to the perpendicular line connecting the first and fifth metatarsal heads. The average interrater reliability across all of the measurements was 0.921.

CONCLUSIONS

This study provides the positional relationship of the DPAA with respect to the distal metatarsal parabola. This method is easily reproducible and may assist the foot and ankle surgeon with surgical planning and approach when performing partial pedal amputation.

Lower extremity reamputation in people with diabetes: a systematic review and meta-analysis

In this study, we determined the reamputation-free survival to both limbs and to the contralateral limb only following an index amputation of any-level and assessed whether reamputation rates have changed over time. We completed a systematic search using PubMed and screened a total of 205 articles for data on reamputation rates. We reported qualitative characteristics of 56 studies that included data on reamputation rates and completed a meta-analysis on 22 of the studies which enrolled exclusively participants with diabetes. The random-effects meta-analysis fit a parametric survival distribution to the data for reamputations to both limbs and to the contralateral limb only. We assessed whether there was a temporal trend in the reamputation rate using the Mann-Kendall test. Incidence rates were high for reamputation to both limbs and to the contralateral limb only. At 1 year, the reamputation rate for all contralateral and ipsilateral reamputations was found to be 19% (IQR=5.1%-31.6%), and at 5 years, it was found to be 37.1% (IQR=27.0%-47.2%). The contralateral reamputation rate at 5 years was found to be 20.5% (IQR=13.3%-27.2%). We found no evidence of a trend in the reamputation rates over more than two decades of literature analyzed. The incidence of lower extremity reamputation is high among patients with diabetes who have undergone initial amputations secondary to diabetes, and rates of reamputation have not changed over at least two decades.

Free Tissue Transfer after Open Transmetatarsal Amputation in Diabetic Patients

BACKGROUND

 Transmetatarsal amputation (TMA) preserves functional gait while avoiding the need for prosthesis. However, when primary closure is not possible after amputation, higher level amputation is recommended. We hypothesize that reconstruction of the amputation stump using free tissue transfer when closure is not possible can achieve similar benefits as primarily closed TMAs.

METHODS

 Twenty-eight TMAs with free flap reconstruction were retrospectively reviewed in 27 diabetic patients with a median age of 61.5 years from 2004 to 2018. The primary outcome was limb salvage rate, with additional evaluation of flap survival, ambulatory status, time until ambulation, and further amputation rate. In addition, subgroup analysis was performed based on the microanastomosis type.

RESULTS

 Flap survival was 93% (26 of 28 flaps) and limb salvage rate of 93% (25 of 27 limbs) was achieved. One patient underwent a second free flap reconstruction. In the two failed cases, higher level amputation was required. Thirteen flaps had partial loss or other complications which were salvaged with secondary intension or skin grafts. Median time until ambulation was 14 days following reconstruction (range: 9-20 days). Patients were followed-up for a median of 344 days (range: 142-594 days). Also, 88% of patients reported good ambulatory function, with a median ambulation score of 4 out of 5 at follow-up. There was no significant difference between the subgroups based on the microanastomosis type.

CONCLUSION

 TMA with free flap reconstruction is an effective method for diabetic limb salvage, yielding good functional outcomes and healing results.

Transmetatarsal Amputation Outcomes When Utilized to Address Foot Gangrene and Infection: A Retrospective Chart Review

A transmetatarsal amputation (TMA) is a widely utilized procedure to address foot gangrene and infection. Although a common procedure, so too are the associated complications. The purpose of this review was to evaluate TMA healing and to explore if there were associated variables correlating with healed vs. failed to heal TMA sites. To do so, the Medical Department Orthopaedics Division Electronic Database, West Virginia University, College of Medicine was retrospectively searched to identify all cases of TMAs (CPT code 28805) during the period of January 2011 through June 2019, and those variables that might impact TMA healing. Then both univariate and multivariable logistic regression analyses were performed to investigate the associations between these variables and TMA healing, and sensitivity analyses were also conducted to determine if the results resisted the influence of one unmeasured confounder. There were 39 patients (41 procedures) who would undergo a TMA. The mean average patient age was 53 (range 29-73) years old. The median postoperative follow-up period was 617 (range 199-3632) days. TMA mortality data revealed 0 deaths at 30 days, 2 (5.1%) at 1 year, 8 (20.5%) at 5 years. In our study, 29 (70.7%) of the TMAs would achieve primary healing at a median of 31 (range 16-253) days. When comparing the TMA healed group to the failed to heal group the following independent variables were considered: diabetes mellitus, HgA1c >8%, neuropathy, peripheral arterial disease, chronic kidney disease, active smoking status, previous surgery, and a clean margin metatarsal bone pathology specimen positive for osteomyelitis. Of the aforementioned, only neuropathy (odds ratio [OR] = 0.056, 95% confidence interval [CI] = 0-0.501, p = .0062) and positive bone margin (OR = 0.144, 95% CI = 0.022-0.835, p = .0385) were found to be significant in univariate logistic regression analysis. In multivariable logistic regression analyses where the potential confounders age, gender, and body mass index were accounted for, of the 8 independent variables of interest, only neuropathy (OR = 0.037, 95% CI = 0-0.497, p = .0036) remained significantly associated with the healing status. Neuropathy was present in 17 (58.6%) of the healed TMAs and in 12 (100%) of the failed to heal TMAs. However, the positive bone margin failed to reach statistical significance (OR = 0.079, 95% CI = 0-1.39, p = .1331). Results from another multivariable logistic regression model where a quadratic term for age was added revealed that positive bone specimen correlated with the TMA healing status with significance (OR = 0.051, 95% CI = 0.001- 0.560, p = .0404). A positive clean margin bone specimen was found in 3 (10.3%) of the healed TMAs and in 4 (44.4%) of the failed to heal TMAs. The sensitivity analysis where current ulceration was used as an unmeasured confounder indicated that the results regarding the association between neuropathy or positive bone margin and TMA healing, though inconclusive, resisted the influence of this unmeasured confounder. Hopefully these findings will be a beneficial addition to the current TMA literature and as such, further assist with informed surgical decision making.

Present-day analysis of early failure after forefoot amputation

BACKGROUND

Forefoot transmetatarsal amputation is performed commonly to achieve limb salvage, but transmetatarsal amputations have a high rate of failure, requiring more proximal amputations. Few contemporary studies have examined the incidence of major amputation (transtibial or transfemoral) after transmetatarsal amputation. The goal of this study is to determine risk factors and outcomes for a more proximal amputation after forefoot amputation.

METHODS

We queried the 2012 to 2016 database of the American College of Surgeons National Quality Improvement Program for patients undergoing a complete transmetatarsal amputation with wound closure by Current Procedural Terminology code. Patients requiring early (within 30 days) more proximal amputation after transmetatarsal amputation were compared with those who did not need further amputation. Characteristics of patients requiring more proximal amputation were examined, and a multivariable logistic regression model was created to identity risk factors for early more proximal amputation.

RESULTS

In the study, 1,582 transmetatarsal amputation were identified. Most patients were male (70%), white (59%), and diabetic (74%), with a median age of 63 years. More proximal amputation occurred in 4.2% of patients within the first 30 days postoperatively. This early failure was associated with greater hospital stays postoperatively (10 days vs 7 days), more wound complications (29% vs 11%), pneumonia (8% vs 2%), stroke (3% vs 0.1%), and overall complications (50% vs 28%; P ≤ .025 each). Although there was no difference in 30-day mortality (P = .27), there was a marked increase in unplanned readmission (59% vs 14%; P < .0001) for those undergoing reamputation. On multivariable analysis, preoperative systemic inflammatory response, sepsis, or septic shock (odds ratio 2.1; 95% confidence interval, 1.2-3.6) were independent predictors of more proximal amputation.

CONCLUSION

Early below-knee or above-knee amputation early after transmetatarsal amputation leads to increased morbidity. Because patients with preoperative sepsis may be at increased risk of failure after transmetatarsal amputation, the level of amputation should be considered carefully in these patients.

Revision After Total Transmetatarsal Amputation

Total transmetatarsal amputation (TMA) can be an option for foot salvage in gangrene, sepsis, or infected necrosis. However, the literature concerning predictive outcome factors and bacterial sampling is scarce. To identify potential associations between revision surgery and underlying bacteria or other preoperative selection criteria, we reviewed all patients with TMA who were treated at our institution. We compared the patients with remissions with surgical revisions. Among 96 adult patients with TMA (105 amputations), 42 required a revision surgery (40%), 18 had a further minor proximal surgical reamputation (17%) and 18 had a major proximal surgical reamputation (14%). In group comparisons, a previous infection with Staphylococcus aureus was protective with a lower revision risk (4/26 with revision surgery vs 22/26 without revisions; p = .03). This was the opposite for postoperative persistent soft tissue or bone infections (p < .01) and delayed wound healing (p < .01), which were positively associated with a revision risk. The American Society of Anesthesiologists Score, sex, age, body mass index, diabetes, polyneuropathy, chronic renal failure, dialysis, peripheral arterial disease, smoking status, and antibiotic regimen did not influence this revision risk. These results must be interpreted cautiously because no multiple variable calculations could be conducted as a result of the paucity of cases and confounding could not be evaluated sufficiently. TMA is an option to prevent major amputations, but it may be associated with a subsequent revision risk of 40% in adult patients. In our cohort study, persistent postamputation infection and delayed wound healing were associated with revision. However, no preoperative selection criteria were found that lead to revision surgery except for an infection with Staphylococcus aureus, which protected against revision surgery.

Predicting reamputation risk in patients undergoing lower extremity amputation due to the complications of peripheral artery disease and/or diabetes

Background

Patients undergoing amputation of the lower extremity for the complications of peripheral artery disease and/or diabetes are at risk of treatment failure and the need for reamputation at a higher level. The aim of this study was to develop a patient-specific reamputation risk prediction model.

Methods

Patients with incident unilateral transmetatarsal, transtibial or transfemoral amputation between 2004 and 2014 secondary to diabetes and/or peripheral artery disease, and who survived 12 months after amputation, were identified using Veterans Health Administration databases. Procedure codes and natural language processing were used to define subsequent ipsilateral reamputation at the same or higher level. Stepdown logistic regression was used to develop the prediction model. It was then evaluated for calibration and discrimination by evaluating the goodness of fit, area under the receiver operating characteristic curve (AUC) and discrimination slope.

Results

Some 5260 patients were identified, of whom 1283 (24·4 per cent) underwent ipsilateral reamputation in the 12 months after initial amputation. Crude reamputation risks were 40·3, 25·9 and 9·7 per cent in the transmetatarsal, transtibial and transfemoral groups respectively. The final prediction model included 11 predictors (amputation level, sex, smoking, alcohol, rest pain, use of outpatient anticoagulants, diabetes, chronic obstructive pulmonary disease, white blood cell count, kidney failure and previous revascularization), along with four interaction terms. Evaluation of the prediction characteristics indicated good model calibration with goodness-of-fit testing, good discrimination (AUC 0·72) and a discrimination slope of 11·2 per cent.

Conclusion

A prediction model was developed to calculate individual risk of primary healing failure and the need for reamputation surgery at each amputation level. This model may assist clinical decision-making regarding amputation-level selection.

Risk Factors for Below-the-Knee Amputation in Diabetic Foot Osteomyelitis After Minor Amputation

BACKGROUND

Below-the-knee amputation (BKA) can be a detrimental outcome of diabetic foot osteomyelitis (DFO). Ideal treatment of DFO is controversial, but studies suggest minor amputation reduces the risk of BKA. We evaluated risk factors for BKA after minor amputation for DFO.

METHODS

This is a retrospective cohort of patients discharged from Denver Health Medical Center from February 1, 2012, through December 31, 2014. Patients who underwent minor amputation for diagnosis of DFO were eligible for inclusion. The outcome evaluated was BKA in the 6 months after minor amputation.

RESULTS

Of 153 episodes with DFO that met the study criteria, 11 (7%) had BKA. Failure to heal surgical incision at 3 months (P < .001) and transmetatarsal amputation (P = .009) were associated with BKA in the 6 months after minor amputation. Peripheral vascular disease was associated with failure to heal but not with BKA (P = .009). Severe infection, bacteremia, hemoglobin A_1c, and positive histopathologic margins of bone and soft tissue were not associated with BKA. The median antibiotic duration was 42 days for positive histopathologic bone resection margin (interquartile range, 32-47 days) and 16 days for negative margin (interquartile range, 8-29 days). Longer duration of antibiotics was not associated with lower risk of BKA.

CONCLUSIONS

Patients who fail to heal amputation sites in 3 months or who have transmetatarsal amputation are at increased risk for BKA. Future studies should evaluate the impact of aggressive wound care or whether failure to heal is a marker of another variable.

Three-Year Morbidity and Mortality Rates After Nontraumatic Transmetatarsal Amputation

Patients requiring a nontraumatic transmetatarsal amputation (TMA) typically have multiple comorbidities that place them at high risk of postoperative complications and additional surgery. The present study identified the demographic, clinical, and surgical risk factors that predict complications after a nontraumatic TMA, including the incidence of 3-year mortality, proximal limb amputation, and lack of healing. The electronic medical records of patients who had undergone TMA within a Kaiser Permanente Northern California facility from March 2007 to January 2012 (n = 375) were reviewed. We used bivariate and multivariate analyses to examine the variations in the rates of TMA complications according to sex, age, race, and comorbid conditions, including nonpalpable pedal pulses, end-stage renal disease, coronary artery disease, hypertension, smoking status, and preoperative albumin <3.5 mg/dL. After a nontraumatic TMA, 136 (36.3%) patients had died within 3 years, 138 (36.8%) had required a more proximal limb amputation, and 83 (22.1%) had healed without complications. The patients with nonpalpable pedal pulses had 3 times the odds of requiring a proximal limb amputation (adjusted odds ratio [aOR] 3.07; 95% confidence interval [CI] 1.84 to 5.11), almost twice the odds of dying within 3 years (aOR 1.70; 95% CI 0.98 to 2.93), and >2 times the odds of not healing after the TMA (aOR 2.45; 95% CI 1.40 to 4.31). The patients with end-stage renal disease had 3 times the odds of dying within 3 years (aOR 3.10; 95% CI 1.69 to 5.70). The present findings can help us identify patients with an increased risk of postoperative complications after nontraumatic TMA, including patients with nonpalpable pedal pulses or end-stage renal disease, and suggest the vulnerability of this patient population.

Anatomic Limitations of the Transmetatarsal Amputation With Consideration of the Deep Plantar Perforating Branch of the Dorsalis Pedis Artery

The transmetatarsal amputation is considered a durable procedure with respect to limb salvage when managing the consequences of diabetic foot disease. The success of the procedure is, in part, determined by the preoperative appreciation of arterial and functional status. The objectives of the present investigation were to determine the length of the remaining first metatarsal required during transmetatarsal amputation to preserve the anastomotic connection of the deep plantar perforating artery and subsequent "vascular arch" of the foot and the insertion of the tibialis anterior tendon. The primary outcome measure of our investigation was a measurement of the distance between the first metatarsal-medial cuneiform articulation and the distal extent of the deep plantar perforating artery in 85 embalmed lower limbs. As a secondary outcome measure, the insertion of the tibialis anterior tendon was evaluated relative to the deep plantar perforating artery. The most distal extent of the deep plantar perforating artery was observed at a mean ± standard deviation of 15.62 ± 3.74 (range 6.0 to 28.28) mm from the first metatarsal-medial cuneiform articulation. Most (89.41%) of the arteries were found within 20 mm of the first metatarsal-medial cuneiform articulation. The insertion of the tibialis anterior tendon was found to be proximal to the deep plantar perforating artery in all specimens (100.0%). In conclusion, 2.0 cm of remnant first metatarsal might represent an anatomic definition of how "short" a transmetatarsal amputation can safely be performed in most patients when considering the vascular and biomechanical anatomy.

Outcomes of Wound Healing and Limb Loss After Transmetatarsal Amputation in the Presence of Peripheral Vascular Disease

Transmetatarsal amputation (TMA) is the procedure of choice in treating forefoot gangrene and infection. Foot and ankle and vascular surgeons work closely together in limb salvage, but little is known about the timing of vascular intervention to achieve a healed amputation site. This study retrospectively looked at 153 patients with peripheral vascular disease who underwent TMA with a minimum of a 3-year follow-up. A total of 102 patients received vascular intervention: 79 endovascular and 23 open bypass. The primary focus of this study was to look at the timing of vascular intervention, incidence of wound healing, and incidence of limb loss. There was an overall 44% rate of limb loss. Patients who underwent open bypass did better than those who underwent endovascular intervention with a lower incidence of limb loss (87% compared with 51%), and quicker time to wound healing. The timing of vascular intervention, performed either before or after TMA, had no association with wound healing or limb loss. Similarly, the time interval between vascular intervention and TMA had no association with wound healing or limb loss. Comorbidities, including end-stage renal disease on hemodialysis, hyperlipidemia, and congestive heart failure, showed a significant association with TMA stump nonhealing and limb loss. Body mass index ≥30, end-stage renal disease on hemodialysis, and hyperlipidemia were all risk factors for limb loss.

One-day low-intensity combined arm-leg (Cruiser) ergometer exercise intervention: cardiorespiratory strain and gross mechanical efficiency in one-legged and two-legged exercise

This study aims to research whether there is a difference in cardiorespiratory variables and gross mechanical efficiency (GE) in healthy individuals during low-intensity one-legged and two-legged exercise on the combined arm-leg (Cruiser) ergometer and whether motor learning occurs. The outcome of this study will support the use of the Cruiser ergometer in future as a testing and training instrument in the rehabilitation of patients with a lower limb amputation. Twenty-eight healthy men participated in this randomized-controlled trial. One group (n=14) used one leg and both arms during the exercise and the other group (n=14) used both legs and both arms. All participants performed a 1-day low-intensity exercise protocol. This included a standardized pretest and post-test of three bouts of 4 min exercise at 40 W and an exercise intervention of seven bouts of 2×4 min exercise at 40 W. The one-legged and two-legged group differed significantly in the heart rate and GE between the pretest and post-test. At the post-test, the one-legged group showed motor learning. GE improved significantly in both groups over the duration of the three exercise bouts of the pretest, but it did not improve during the post-test. There are differences in cardiorespiratory variables and GE between one-legged and two-legged exercise on the Cruiser ergometer. When using this ergometer in the rehabilitation of patients with a lower limb amputation, it is important to consider these differences and the occurrence of motor learning.

An Approach to Transmetatarsal Amputation to Encourage Immediate Weightbearing in Diabetic Patients

Transmetatarsal amputation remains the standard treatment for the unsalvageable diabetic forefoot; however, this operation is often complicated by wound dehiscence, ulceration, and the need for additional surgery and tendon balancing. The technique described in the present report provides an uncomplicated suturing method for closure of a standard transmetatarsal amputation. A drill hole is created through the first, second, and fourth metatarsals, which facilitates added stability to the plantar flap of the residual metatarsals. The patients are encouraged to begin protected weightbearing as early as the first postoperative day. The security of the flap promotes immediate weightbearing, which could result in fewer postoperative complications of transmetatarsal amputations. Early weightbearing will not only encourage tendon rebalancing, but also could improve angiogenesis through capillary ingrowth.

Reoperation and Reamputation After Transmetatarsal Amputation: A Systematic Review and Meta-Analysis

Transmetatarsal amputations have generally been accepted as a relatively more definitive amputation compared with other lesser ray resections. However, many investigators have reported a high occurrence of more proximal amputation after transmetatarsal amputation. A systematic review was performed to evaluate the occurrence of reamputation and reoperation after transmetatarsal amputations. A search of the Medline, CINAHL, and Cochrane Central databases yielded 159 abstracts. After review, 24 reports were included in the study. A total of 391 (26.9%) reoperations were identified after 1453 transmetatarsal amputations. Any level reamputation occurred in 152 (29.7%) of 365 transmetatarsal amputations and major amputation occurred in 380 (33.2%) of 1146 transmetatarsal amputations. Using a random effects model, the reoperation rate was estimated at 24.43% (95% confidence interval 11.64% to 37.21%), the reamputation rate was estimated at 28.37% (95% confidence interval 19.56% to 37.19%), and the major amputation rate was estimated at 30.16% (95% confidence interval 23.86% to 36.47%). These findings raise questions about the conventional wisdom of performing primary transmetatarsal amputation in lieu of other minor amputations, such as partial first ray amputation, and suggest that the choice between transmetatarsal amputation and other minor amputations might be a decision that depends on very patient-specific factors.

Incidence of lower limb amputation in Australian hospitals from 2000 to 2010

BACKGROUND

Contemporary literature reports that the incidence of lower limb amputation has declined in many countries. This impression may be misleading given that many publications only describe the incidence of lower limb amputations above the ankle and fail to include lower limb amputations below the ankle.

OBJECTIVES

To describe trends in the incidence of different levels of lower limb amputation in Australian hospitals over a 10-year period.

STUDY DESIGN

Descriptive.

METHOD

Data describing the age-standardised incidence of lower limb amputation were calculated from the Australian National Hospital Morbidity database and analysed for trends over a 10-year period.

RESULTS

The age-standardised incidence of lower limb amputation remained unchanged over time (p = 0.786). A significant increase in the incidence of partial foot amputations (p = 0.001) and a decline in the incidence of transfemoral (p = 0.00) and transtibial amputations (p = 0.00) were observed. There are now three lower limb amputations below the ankle for every lower limb amputation above the ankle.

CONCLUSION

While the age-standardised incidence of all lower limb amputation has not changed, a shift in the proportion of lower limb amputations above the ankle and lower limb amputations below the ankle may be the result of improved management of precursor disease that makes partial foot amputation a more commonly utilised alternative to lower limb amputations above the ankle. Clinical relevance This article highlights that although the incidence of lower limb amputation has remained steady, the proportion of amputations above the ankle and below the ankle has changed dramatically over the last decade. This has implications for how we judge the success of efforts to reduce the incidence of lower limb amputation and the services required to meet the increasing proportion of persons with amputation below the ankle.

Contemporary evaluation and management of the diabetic foot

Foot problems in patients with diabetes remain a major public health issue and are the commonest reason for hospitalization of patients with diabetes with prevalence as high as 25%. Ulcers are breaks in the dermal barrier with subsequent erosion of underlying subcutaneous tissue that may extend to muscle and bone, and superimposed infection is a frequent and costly complication. The pathophysiology of diabetic foot disease is multifactorial and includes neuropathy, infection, ischemia, and abnormal foot structure and biomechanics. Early recognition of the etiology of these foot lesions is essential for good functional outcome. Managing the diabetic foot is a complex clinical problem requiring a multidisciplinary collaboration of health care workers to achieve limb salvage. Adequate off-loading, frequent debridement, moist wound care, treatment of infection, and revascularization of ischemic limbs are the mainstays of therapy. Even when properly managed, some of the foot ulcers do not heal and are arrested in a state of chronic inflammation. These wounds can frequently benefit from various adjuvants, such as aggressive debridement, growth factors, bioactive skin equivalents, and negative pressure wound therapy. While these, increasingly expensive, therapies have shown promising results in clinical trials, the results have yet to be translated into widespread clinical practice leaving a huge scope for further research in this field.

Transmetatarsal amputation: a case series and review of the literature

Foot ulceration is a major cause of morbidity amongst patients with diabetes. In severe cases of ulceration, osteomyelitis and amputation can ensue. A distinct lack of agreement exists on the most appropriate level of amputation in cases of severe foot ulceration/infection to provide predictable healing rates. This paper provides an overview of the transmetatarsal amputation (TMA) as a limb salvage procedure and is written with the perspective and experiences of the Department of Podiatric Surgery at West Middlesex University Hospital (WMUH). We have reflected on the cases of 11 patients (12 feet) and have found the TMA to be an effective procedure in the management of cases of severe forefoot ulceration and infection.

Preoperative Doppler assessment for transmetatarsal amputation

A thorough preoperative vascular evaluation should be performed before the initiation of any lower extremity surgical intervention, but particularly in situations of diabetic foot reconstruction with compromised blood flow. The intended emphasis of this brief report is to provide the foot and ankle surgeon with an appreciation for the clinical vascular anatomy of the transmetatarsal amputation through a handheld Doppler examination.

New and recurrent ulcerations after percutaneous achilles tendon lengthening in transmetatarsal amputation

The purpose of the study was to review the incidence rate of new and recurrent ulcerations in transmetatarsal amputations after original ulcers healed with percutaneous Achilles' tendon lengthening as an isolated procedure. We reviewed 35 charts from period of January 1995 to March 2007, and 28 were included for the final review. Twenty-four ulcers were grade 1A, 2 were 0A and 1B, and 1 was 1C using the University of Texas Grading System. Time to heal of ulceration post-TAL was 9.4 weeks (range 3-72 weeks). For statistical analysis, we used binomial distribution for dichotomous variables. Results demonstrated 4 limbs did not heal, 10 patients had an ulcer recurrence (p<0.001), and 6 developed new ulcers. Of the 28 patients in which TAL was performed, 16 developed new neuropathic ulcers (including recurrent ulcers; p=0.0099). High recurrence and new ulcers formation exist after TAL in patients with an unbalanced metatarsal amputation, and extrinsic/ intrinsic factors may need to be addressed to prevent recurrence.

LEVEL OF CLINICAL EVIDENCE

4.