Lower Limb Amputation Rates in Germany

[Agonist-antagonist myoneural interface (AMI) : Innovative treatment option for lower limb amputees?]

The agonist-antagonist myoneural interface (AMI) is an innovative approach to restoring proprioception and achieving more intuitive motor control following limb loss. This cutting-edge technique replicates the natural biomechanical relationship between agonist and antagonist muscles, enabling bidirectional communication between a prosthesis and the user's peripheral nervous system. Through the transposition of neurovascularly pedicled agonist-antagonist muscle pairs, which are reconnected via an adapted tendon suture and positioned within a gliding mechanism, AMI generates proprioceptive feedback during movement. Changes in tension within these muscle pairs produce signals that are transmitted to the central nervous system via afferent nerve pathways, enabling users to perceive the joint position of the limb that was originally governed by the muscle pair. This enhanced sensory input significantly facilitates control of the prosthesis. The AMI appears to enable an integration of the prosthesis into the body's existing neural networks and improve motor control of the prosthesis and the sensory discrimination. Compared to traditional surgical techniques (myodesis or myoplasty) with a purely mechanical transposition of residual stump muscles, AMI reduces the cognitive burden during the use of the prosthesis and delivers a more natural sense of movement, fostering a profound sense of embodiment. In summary, AMI represents a significant leap forward in human-machine integration. By enhancing both the functionality and user experience of prosthetic devices, it provides a very promising transformative solution for sustainable improvement of the quality of life for individuals living with limb loss.

Gait Characteristics of People with Hallux and Forefoot Amputations-A Case Series

Background/Objectives: Minor amputations are increasingly relevant due to a growing proportion of lower limb amputations but remain underrepresented in research. These amputations impair mobility due to altered gait, and biomimetic devices could potentially address this issue. Fundamental research is needed to better understand this pathological gait pattern. The aim of this study is to analyse the holistic gait characteristics of the lower extremity during barefoot walking in individuals with different levels of minor amputations for the first time. Methods: Eight young to middle-aged subjects with minor foot amputations (four × hallux; four × forefoot) underwent instrumented gait analysis. Kinematic and kinetic data were acquired barefoot at self-selected gait speeds. Individual gait characteristics were considered relative to the physiological gait represented by the 95% confidence interval of ten unimpaired volunteers. Results: Subjects with a minor amputation show reduced walking speed and shorter stride length compared to controls. Sagittal ankle moment and ankle power are lower, with greater deficits in subjects with a forefoot amputation. Proximal joints also show variability, notably reduced knee flexion in subjects with a forefoot amputation and a more flexed hip profile in six subjects. Single-subject frontal plane kinetics also vary. Conclusions: Although the subjects with a hallux amputation exhibit smaller deviations in ankle kinetics than the subjects with a forefoot amputation, proximal joint abnormalities are present across cases. These findings highlight the need for a broad range of care to adequately address individual needs.

Epidemiology of first-time major lower extremity amputations- A Danish Nationwide cohort study from 2010 to 2021

BACKGROUND AND AIM

Major lower extremity amputations (MLEA) are common procedures. Potential changes in surgical strategy and patient characteristics over time have not been described previously. The aim of this study was to investigate the incidence rates and surgical strategies of first-time MLEAs over time from 2010 to 2021. Furthermore, to describe patient demographics, and their changes in the same period.

METHODS

This is an observational nationwide register study including all first-time MLEAs performed in patients ≥ 18 years from 2010 to 2021, with data from the Danish National Patient Register.

RESULTS

A total of 12,672 first-time MLEA patients were identified from 2010 to 2021. The annual number of first-time MLEAs each year was unchanged at approx. 1000 annually during the study period. In 2021 the total incidence was 21.3/100,000 inhabitants and the total adjusted incidence rate decreased by 2.3% (95% CI 1.8-2.8) per year. The adjusted frequency of transfemoral amputations increased significantly with 10.9% each year confidence interval (CI) (9.7-12.0), whereas knee disarticulation(-19.4%/year CI (-22.2- -16.5)) and transtibial amputation (-7.3%/year CI (-8.5- -6.1)) significantly decreased. The frequency of primary hip disarticulations were stable throughout the study period (p-value 0.06). When analyzing patient comorbidity profiles we found no major changes over time. When statistically testing for time trends, only dyslipidemia (5.7%/year CI (4.5-7.1)), renal insufficiency (1.8%/year CI(0.2-3.3), peripheral artrial disease (-9.3%/year CI (-10.8- -7.7)) and cardiovascular disease (-3.4%/year CI(-4.6- -2.1)) showed a significant time trend in the study period.

CONCLUSIONS

We observed a decreasing incidence of first-time MLEA in Denmark and a shift towards increased use of transfemoral amputations as initial MLEA level. Investigation of the comorbidity profile of MLEA patients revealed some time trend changes during the study period, but with limited clinical relevance. Hence, the observed prominent shift towards a more proximal first time amputation level in Denmark did not seem to be associated with an altered comorbidity profile of these patients. Whether the change in surgical strategy is to the benefit of the patients should be investigated further.

Pain After Lower Limb Amputations: Insights from the Heidelberg Amputation Registry

Background and Objectives: The experience of unpleasant sensory phenomena after lower limb amputations (LLAs), including phantom limb pain (PLP), phantom limb sensation (PLS), and residual limb pain (RLP), impacts global healthcare and adversely affects outcomes post-amputation. This study aimed to describe the distribution of PLP, PLS, and RLP among patients with LLAs registered in the Heidelberg Amputation Registry. The primary objective was to determine the prevalence of sensory abnormalities across different amputation levels and causes. Materials and Methods: In this single-center, cross-sectional study, data from 459 patients registered in the Heidelberg Amputation Registry were analyzed for the occurrence of PLP, PLS and RLP. Subsequently, logistic regression models were used to identify the independent risk factors associated with sensory disturbances following LLAs. The mean age of the LLA patients (31% female, 69% male) was 58 years (SD ± 18). Results: The patients were, on average, 44 years old (SD ± 22) at the time of amputation, with a mean duration since amputation of 15 years (SD ± 17). Transtibial amputations were the most common (43%), followed by transfemoral (39%) and partial foot amputations (10%). Hip and knee disarticulations were observed in 3.7% and 3.5% of the cohort, respectively, with hemipelvectomies accounting for 1%. Traumatic injuries (32%) and neoplastic disorders (22%) were the leading causes of LLAs, while peripheral artery disease and diabetes were responsible for 12% and 6% of cases, respectively. Importantly, a significant proportion of participants (85%) reported experiencing abnormal sensations. The prevalence rates for phantom limb pain (PLP), phantom limb sensation (PLS), and residual limb pain (RLP) were 58%, 66%, and 46%, respectively. The occurrence of sensory disturbances, with the exception of RLP, was significantly affected by the level of amputation. Notably, the age at amputation emerged as an independent risk factor for developing abnormal sensations, including PLS. Conclusions: In conclusion, this study provides a comprehensive overview of sensory abnormalities in a diverse cohort of LLA patients, highlighting the age at amputation as an important factor. The findings emphasize the role of comprehensive registries in enhancing care for individuals with amputations and guiding targeted pain management strategies.

Epidemiology and Impact of Limb Loss in the United States and Globally

The main causes of limb loss include trauma, complications from diabetes and peripheral arterial disease, malignancy, and congenital limb deficiency. There are significant geographic variations in the incidence of upper and lower, and major and minor limb loss worldwide. Limb loss is costly for patients and the health care system. The availability of orthotic and prosthetic services, along with cost of services, represents barrier to care and contributes to morbidity and mortality. More research is needed, especially in low-income and middle-income countries to describe the extent of limb loss.

Artificial intelligence's suggestions for level of amputation in diabetic foot ulcers are highly correlated with those of clinicians, only with exception of hindfoot amputations

Diabetic foot ulcers (DFUs) are a growing public health problem, paralleling the increasing incidence of diabetes. While prevention is most effective treatment for DFUs, challenge remains on selecting the optimal treatment in cases with DFUs. Health sciences have greatly benefited from the integration of artificial intelligence (AI) applications across various fields. Regarding amputations in DFUs, both literature and clinical practice have mainly focused on strategies to prevent amputation and identify avoidable risk factor. However, there are very limited data on assistive parameters/tools that can be used to determine the level of amputation. This study investigated how well ChatGPT, with its lately released version 4o, matches the amputation level selection of an experienced team in this field. For this purpose, clinical photographs from patients who underwent amputations due to diabetic foot ulcers between May 2023 and May 2024 were submitted to the ChatGPT-4o program. The AI was tasked with recommending an appropriate amputation level based on these clinical photographs. Data from a total of 60 patients were analysed, with a median age of 64.5 years (range: 41-91). According to the Wagner Classification, 32 patients (53.3%) had grade 4 ulcers, 16 patients (26.6%) had grade 5 ulcers, 10 patients (16.6%) had grade 3 ulcers and 2 patients (3.3%) had grade 2 ulcers. A one-to-one correspondence between the AI tool's recommended amputation level and the level actually performed was observed in 50 out of 60 cases (83.3%). In the remaining 10 cases, discrepancies were noted, with the AI consistently recommending a more proximal level of amputation than what was performed. The inter-rater agreement analysis between the actual surgeries and the AI tool's recommendations yielded a Cohen's kappa coefficient of 0.808 (SD: 0.055, 95% CI: 0.701-0.916), indicating substantial agreement. Relying solely on clinical photographs, ChatGPT-4.0 demonstrates decisions that are largely consistent with those of an experienced team in determining the optimal level of amputation for DFUs, with the exception of hindfoot amputations.

When the Going Gets Tough: A Review of Total Hip Arthroplasty in Patients with Ipsilateral Above- and Below-Knee Amputation

Life expectancy and overall function of amputated patients have improved significantly over the last few decades; for this reason, amputees are more exposed to primary or secondary degenerative disease of the hip, requiring total hip arthroplasty (THA) surgery. However, during training, not all the surgeons acquire adequate skills to manage these patients, and only a few studies and case reports describe technical pearls and outcomes of THA in patients with ipsilateral lower limb amputation, either above or below the knee. The objective of this narrative review is to present current evidence and surgical tips for performing THA in ipsilateral amputated patients, with a focus on the differences between patients with above- (AKA) and below-knee amputation (BKA). We reviewed manuscripts in major scientific databases, cross-referencing to retrieve adjunctive manuscripts, and summarized all relevant cases. We found 17 manuscripts, spanning 70 years of literature, collecting a total of 39 patients who underwent THA on an ipsilateral amputated limb: 13 AKA, 23 BKA, and 3 through-knee-amputation (TKA). The cohort primarily consists of patients with post-traumatic hip arthritis, often associated with sequelae such as fractures to other bones, soft tissue compromise and heterotopic calcifications. Managing with amputated patients requires careful planning, which includes the study of the residual bone, muscle anatomy, and the level of femoral amputation, as these factors present significant surgical challenges, especially in patients without a knee joint. In dealing with the post-traumatic and multi-comorbidity patients, rehabilitation goals should be considered prior to surgery and should drive the surgical strategy. We found that BKA patients typically have high functional demands, necessitating precise positioning of the components and an aggressive post-operative physiotherapy regimen to avoid unsatisfactory outcomes. AKA patients, on the other hand, often present with altered anatomy, and typically require more surgical instruments and expertise to achieve intraoperative dislocation of the hip joint.

Editor's Choice - Analysis of Lower Limb Amputations in Brazil's Public Health System over 13 Years

OBJECTIVE

Understanding the causes of amputation is crucial for defining health policies that seek to avoid such an outcome, but only a few studies have investigated the epidemiology of patients submitted to amputations in developing countries. The objective of this study was to analyse all lower limb amputations performed in the public health system in Brazil over a 13 year period, evaluating trends in the number of cases, patient demographics, associated aetiologies, hospital length of stay, and in hospital mortality rate.

METHODS

This was a retrospective, population based analysis of all lower limb amputations performed in the Brazilian public health system between 1 January 2008 and 31 December 2020. Using a public database, all types of amputations were selected, defining the number of procedures, their main aetiologies, anatomical level of limb loss, demographic data, regional distribution, and other variables of interest.

RESULTS

A total of 633 455 amputations were performed between 2008 and 2020, mostly (55.6%) minor amputations, predominantly in males (67%). There was an upward trend in the number of amputations, determined mainly by the increase in major amputations (50.4% increase in the period). Elderly individuals have the highest rates of amputation. Diabetes mellitus (DM) is becoming the main primary diagnosis associated with amputations over the years. The highest in hospital mortality rate occurred after major amputations and was associated with peripheral arterial disease (PAD).

CONCLUSION

Amputation rates in Brazil show an upward trend. DM is becoming the most frequent associated primary diagnosis, although PAD is the diagnosis most associated with major amputations and in hospital death.

Five-Year Trends of Vascular Disease-Related Amputations in Romania: A Retrospective Database Study

Background/Objectives: Lower extremity amputations (LEAs) are a burdensome complication of peripheral artery disease (PAD) and/or arterial embolism and thrombosis (AET). We assessed the trends in PAD- and/or AET-related LEAs in Romania. Methods: This retrospective study (2015-2019) analyzed data on minor and major LEAs in hospitalized patients recorded in the National School for Public Health, Management, and Health Education database. The absolute numbers and incidences of LEAs were analyzed by diagnosis type, year, age, sex, and amputation level. Results: Of 38,590 vascular disease-related amputations recorded nationwide, 36,162 were in PAD and 2428 in AET patients. The average LEA incidence in the general population was 34.73 (minimum: 31.96 in 2015; maximum: 36.57 in 2019). The average incidence of major amputations, amputations above the knee, hip amputations, amputations below the knee, and minor amputations was 16.21 (15.62 in 2015; 16.84 in 2018), 13.76 (13.33 in 2015; 14.28 in 2018), 0.29 (0.22 in 2017; 0.35 in 2019), 2.15 (2.00 in 2015; 2.28 in 2019), and 18.52 (16.34 in 2015; 20.12 in 2019), respectively. Yearly PAD- and/or AET-related amputations were significantly higher in men versus women. The overall number of LEAs increased with age, particularly in patients ≥ 70 years. The increase in the total number of amputations was mainly due to a constant rise in minor amputations for both groups, regardless of gender. Conclusions: PAD- and/or AET-related LEAs in Romania increased from 2015 to 2019, with men having a greater incidence than women. Raising awareness and effective management strategies are needed to prevent LEAs.

On the Usability of Polymer-Based Artificial Tendons for Elastic Energy Storage in Active Ankle Prostheses

In the recent past, the development of lower-limb prostheses has taken a new turn with the emergence of active systems. However, their intrinsic wearable nature induces strict requirements regarding weight and encumbrance. In order to reduce the load - and thus the bulkiness - of their active part, several prototypes leverage the concept of compliant actuation, consisting in including an elastic element in parallel and/or in series with the actuator. In this paper, we explore the usability of polymer compliant ropes placed in parallel with the actuator of an ankle prosthesis. Ropes are intrinsically light and compact, and thus offer several advantages as compared to more traditional coil or leaf springs. Polymer materials were selected for their high energy density and yield strength. We conducted a set of experimental tests with several ropes, pretension levels, and periodic loading profiles. Results show that polymer-based ropes have a high potential for ankle assistance devices, since they can store the required energy in a low volume. However, further research should be conducted to improve their efficiency, since we estimated that only about 50% of the stored energy can be released, with few variations as a function of the rope preconditioning and loading profile.

Incidence of Lower Extremity Amputation in Romania: A Nationwide 5-Year Cohort Study, 2015-2019

Background and Objectives: The primary objective of this study was to investigate the incidence of lower extremity amputations (LEAs) in a representative population from Romania, in both diabetic and non-diabetic adults, including trauma-related amputations. The secondary objective was to evaluate the trends in LEAs and the overall ratio of major-to-minor amputations. Material and Methods: The study was retrospective and included data from the Romanian National Hospital Discharge Records, conducted between 1 January 2015 and 31 December 2019. Results: The overall number of cases with LEAs was 88,102, out of which 38,590 were aterosclerosis-related LEAs, 40,499 were diabetes-related LEAs, and 9013 were trauma-related LEAs, with an ascending trend observed annually for each of these categories. Of the total non-traumatic amputations, 51.2% were in patients with diabetes. Most LEAs were in men. The total incidence increased from 80.61/100,000 in 2015 to 98.15/100,000 in 2019. Conclusions: Our study reported a 21% increase in total LEAs, 22.01% in non-traumatic LEAs, and 19.65% in trauma-related amputation. The minor-to-major amputation ratio increased over the study period in patients with diabetes. According to these findings, it is estimated that currently, in Romania, there is one diabetes-related amputation every hour and one non-traumatic amputation every 30 min.

Retrospective analysis of mortality and quality of life after hip disarticulation or hemipelvectomy: a report on 15 patients

BACKGROUND

Hip disarticulation and hemipelvectomy are defined as major ablative amputations of the lower limb. Due to the small number of patients, little is known about the outcome and follow-up.

AIMS

We aimed to assess (1) reasons for performed major ablative surgeries such as hip disarticulation and hemipelvectomy in a German center for trauma and orthopedic surgery. (2) In addition, mortality and quality of life after hip disarticulation and hemipelvectomy as well as (3) patient and treatment characteristics should be investigated.

METHODS

During a period of twelve years, 15 patients underwent hip disarticulation or hemipelvectomy. Mortality, EQ-5D-3L quality of life by EQ-5D-3L and time-trade-off (TTO), VAS, cause of disarticulation, length of hospital stays, revisions, comorbidities, Charlson comorbidity index (CCI), and ASA score were evaluated retrospective for all patients.

RESULTS

The overall mortality rates were 26.7% at 30 days, 60.0% after one year and 66.7% after three years. The five surviving patients reported about moderate problems in the EQ-5D-3L. The average VAS score reached 45 (range 15-65). The mean TTO was 9.8 (range 6-12). Indications for amputation were infection (n = 7), tumor (n = 6), trauma (n = 1) and ischemia (n = 1).

CONCLUSION

Hip disarticulation and hemipelvectomy are followed by a high postoperative mortality. Quality of life of the affected patients is impaired in long-term follow-up. Especially amputations performed due to infections show high mortality within one month after surgery despite average young age and low CCI. Surgeons should be aware of this devastating outcome and extraordinary vigilant for these vulnerable patient cohorts.

Demographics and Etiology for Lower Extremity Amputations-Experiences of an University Orthopaedic Center in Germany

Background and Objectives: Currently, the worldwide incidence of major amputations in the general population is decreasing whereas the incidence of minor amputations is increasing. The purpose of our study was to analyze whether this trend is reflected among orthopaedic patients treated with lower extremity amputation in our orthopaedic university institution. Materials and Methods: We conducted a single-center retrospective study and included patients referred to our orthopaedic department for lower extremity amputation (LEA) between January 2007 and December 2019. Acquired data were the year of amputation, age, sex, level of amputation and cause of amputation. T test and Chi² test were performed to compare age and amputation rates between males and females; significance was defined as p < 0.05. Linear regression and multivariate logistic regression models were used to test time trends and to calculate probabilities for LEA. Results: A total of 114 amputations of the lower extremity were performed, of which 60.5% were major amputations. The number of major amputations increased over time with a rate of 0.6 amputation/year. Men were significantly more often affected by LEA than women. Age of LEA for men was significantly below the age of LEA for women (men: 54.8 ± 2.8 years, women: 64.9 ± 3.2 years, p = 0.021). Main causes leading to LEA were tumors (28.9%) and implant-associated complications (25.4%). Implant-associated complications and age raised the probability for major amputation, whereas malformation, angiopathies and infections were more likely to cause a minor amputation. Conclusions: Among patients in our orthopaedic institution, etiology of amputations of the lower extremity is multifactorial and differs from other surgical specialties. The number of major amputations has increased continuously over the past years. Age and sex, as well as diagnosis, influence the type and level of amputation.

The Design of a Smart Lower-Limb Prosthesis Supporting People with Transtibial Amputation—A Data Acquisition System

For people with amputated lower limbs, it is imperative to make high-performance prostheses that reproduce, as accurately as possible, the functions of the amputated limb. In this case, a preliminary study of the lower limbs from a kinematic and dynamic point of view is necessary. This paper proposes a prosthesis design and a system for acquiring the information needed to determine the stepping phase kinematic and dynamic parameters of the legs. This system consists of a sensory system attached to the legs and a acquisition data unit built around a microcontroller. The sensory system is based on a sensory system for determining the weight distribution on the sole, made of resistive pressure sensors. The sensory system will be subjected to measurement repeatability and homogeneity tests to evaluate and validate the accuracy and error of the proposed solution. The data obtained by the sensory system is transmitted in real-time, via wi-fi, to a computer system for interpretation. After processing and interpreting the data using standard data sets for comparison, the position of the legs, the type of gait and the phase of movement can be determined. Constructively, the system is configurable and can be adapted to any person, male or female, regardless of shoe size.

Temporal trends in major, minor and recurrent lower extremity amputations in people with and without diabetes in Belgium from 2009 to 2018

AIMS

This study assessed temporal trends in the incidence of lower extremity amputations (LEA) in Belgium from 2009 to 2018, and subsequent secondary amputation rates.

METHODS

Nationwide data on LEA were collected. Sex- and age-adjusted annual incidence rates were calculated. Time trends were analysed in negative binomial models. The incidence of secondary interventions, defined as either any ipsilateral reamputation or any contralateral amputation, was studied with death as competing risk.

RESULTS

41 304 amputations were performed (13 247 major, 28 057 minor). In individuals with diabetes, the amputation rate (first amputation per patient per year) decreased from 143.6/100.000 person-years to 109.7 (IRR 0.97 per year, 95 %CI 0.96-0.98, p < 0.001). The incidence of major LEAs decreased from 56.2 to 30.7 (IRR 0.93, 95 %CI 0.91-0.94, p < 0.001); the incidence of minor amputations showed a non-significant declining trend in women (54.3 to 45.0/100 000 person years, IRR 0.97 per year, 95 %CI 0.96-0.99), while this remained stable in men with diabetes (149.2 to 135.3/100 000 person years, IRR 1.00 per year, 95 %CI 0.98-1.01). In individuals without diabetes, the incidence of major amputation didn't change significantly, whereas minor amputation incidence increased (8.0 to 10.6, IRR 1.04, 95 %CI 1.03-1.05, p < 0.001). In individuals with diabetes, one-year secondary intervention rates were high (31.3% after minor, 18.4% after major LEA); the incidence of secondary amputations didn't change.

CONCLUSIONS

A significant decline in the incidence rate of major LEA was observed in people with diabetes. This decline was not accompanied by a significant rise in minor LEA. The incidence of secondary interventions remained stable.