Quantifying Bone and Skin Movement in the Residual Limb-Socket Interface of Individuals With Transtibial Limb Loss Using Dynamic Stereo X-Ray: Protocol for a Lower Limb Loss Cadaver and Clinical Study.

BACKGROUND: Relative motion between the residual limb and socket in individuals with transtibial limb loss can lead to substantial consequences that limit mobility. Although assessments of the relative motion between the residual limb and socket have been performed, there remains a substantial gap in understanding the complex mechanics of the residual limb-socket interface during dynamic activities that limits the ability to improve socket design. However, dynamic stereo x-ray (DSX) is an advanced imaging technology that can quantify 3D bone movement and skin deformation inside a socket during dynamic activities. OBJECTIVE: This study aims to develop analytical tools using DSX to quantify the dynamic, in vivo kinematics between the residual limb and socket and the mechanism of residual tissue deformation. METHODS: A lower limb cadaver study will first be performed to optimize the placement of an array of radiopaque beads and markers on the socket, liner, and skin to simultaneously assess dynamic tibial movement and residual tissue and liner deformation. Five cadaver limbs will be used in an iterative process to develop an optimal marker setup. Stance phase gait will be simulated during each session to induce bone movement and skin and liner deformation. The number, shape, size, and placement of each marker will be evaluated after each session to refine the marker set. Once an optimal marker setup is identified, 21 participants with transtibial limb loss will be fitted with a socket capable of being suspended via both elevated vacuum and traditional suction. Participants will undergo a 4-week acclimation period and then be tested in the DSX system to track tibial, skin, and liner motion under both suspension techniques during 3 activities: treadmill walking at a self-selected speed, at a walking speed 10% faster, and during a step-down movement. The performance of the 2 suspension techniques will be evaluated by quantifying the 3D bone movement of the residual tibia with respect to the socket and quantifying liner and skin deformation at the socket-residuum interface. RESULTS: This study was funded in October 2021. Cadaver testing began in January 2023. Enrollment began in February 2024. Data collection is expected to conclude in December 2025. The initial dissemination of results is expected in November 2026. CONCLUSIONS: The successful completion of this study will help develop analytical methods for the accurate assessment of residual limb-socket motion. The results will significantly advance the understanding of the complex biomechanical interactions between the residual limb and the socket, which can aid in evidence-based clinical practice and socket prescription guidelines. This critical foundational information can aid in the development of future socket technology that has the potential to reduce secondary comorbidities that result from complications of poor prosthesis load transmission. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/57329.

Application of ultrasound to monitor in vivo residual bone movement within transtibial prosthetic sockets.

Transtibial prosthetic users do often struggle to achieve an optimal prosthetic fit, leading to residual limb pain and stump-socket instability. Prosthetists face challenges in objectively assessing the impact of prosthetic adjustments on residual limb loading. Understanding the mechanical behaviour of the pseudo-joint formed by the residual bone and prosthesis may facilitate prosthetic adjustments and achieving optimal fit. This study aimed to assess the feasibility of using B-mode ultrasound to monitor in vivo residual bone movement within a transtibial prosthetic socket during different stepping tasks. Five transtibial prosthesis users participated, and ultrasound images were captured using a Samsung HM70A system during five dynamic conditions. Bone movement relative to the socket was quantified by tracking the bone contour using Adobe After-Effect. During the study a methodological adjustment was made to improve data quality, and the first two participants were excluded from analysis. The remaining three participants exhibited consistent range of motion, with a signal to noise ratio ranging from 1.12 to 2.59. Medial-lateral and anterior-posterior absolute range of motion varied between 0.03 to 0.88 cm and 0.14 to 0.87 cm, respectively. This study demonstrated that it is feasible to use B-mode ultrasound to monitor in vivo residual bone movement inside an intact prosthetic socket during stepping tasks.

Feasibility of Magnetic Resonance-Guided High-Intensity-Focused Ultrasound (MRgHIFU) Ablation of Stump Neuromas for the Relief of Chronic Postamputation Neuropathic Pain.

Up to 70% of limb amputees develop chronic postamputation neuropathic pain (CPANP) which includes phantom pain and residual limb neuropathic pain due to neuroma formation. CPANP often requires invasive procedures aimed at neuroma ablation. Five amputees received 6 noninvasive magnetic resonance-guided high-intensity-focused ultrasound MRgHIFU treatments ExAblate®, Insightec, Tirat-Carmel, Israel). Although ablative temperature (>65°C) at the neuroma was reached in only 1 patient, pain intensity dropped from 5.7 at baseline to 4.3 and back to 5.6 at 3 and 6 month follow-up. Post-treatment bone necrosis was demonstrated in 1 patient. Although no firm conclusion about the effectiveness of MRgHIFU for CPANP could be drawn, further studies are warranted.

Icing the Pain-Ultrasound-Guided Cryoablation of Symptomatic Post-Amputation Stump Neuroma.

PURPOSE: To assess the feasibility and outcome of ultrasound-guided cryoablation in patients with a sensitized stump neuroma after limb amputation. MATERIAL AND METHODS: Seven patients (3 females, 4 males; mean age 42 years) were included in this retrospective study. Ultrasound-guided cryoablation of a previously identified painful stump neuroma was performed. Pain was assessed on the visual analogue scale (VAS) and compared before and after cryoablation (Wilcoxon Test). The degree of pain alleviation was correlated with patient age, duration of pain before ablation and time interval between amputation and ablation (Spearman correlation). A p-value less than 0.05 was deemed statistically significant. RESULTS: Nine cryoablations were performed for 8 neuromas. Technical success was 100%, there were no major complications. Mean follow-up was 27 months. There was a statistically significant decrease of pain from mean 8.3 / 10 (baseline) to 4 /10 (on day one), 2.1 / 10 (at one week) and 3 / 10 (at last follow-up) (p < 0.05). Patient satisfaction with cryoablation treatment was very high (median score 70 / 100). CONCLUSION: In our small population observational study, ultrasound-guided cryoablation of a sensitized stump neuroma was effective and safe for pain alleviation with very good long-term results. LEVEL OF EVIDENCE: Level 2, Observational study with dramatic effect.

MRI features of symptomatic amputation neuromas.

OBJECTIVES: To demonstrate the magnetic resonance imaging (MRI) features of amputation neuromas in lower extremity amputees and investigate independent predictive MRI features for symptomatic neuromas. METHODS: This retrospective study included 45 amputation neuromas in 44 lower extremity amputees. Two radiologists assessed the imaging features, including shape, size, type (end-bulb or spindle), signal intensity (SI), heterogeneity, margins, enlarged fascicles, dark outer rim, tail sign, target sign, enhancement, perilesional fibrosis, and muscle denervation. The neuromas were categorized into symptomatic (n = 24) or asymptomatic (n = 21). Symptomatic neuromas were determined based on neuropathic pain characteristics, the presence of Tinel's sign or tenderness, and response to local anesthetic injection. Univariate and multivariate analyses were performed to identify independent predictive MRI features. RESULTS: Of 45 neuromas, 80% (36/45) were end-bulb neuromas and 20% (9/45) were spindle-type neuromas. Eighty percent of the neuromas (36/45) were heterogeneous on T2-weighted images (WIs). Enlarged fascicles were present in 42% (19/45) and dark outer rims in 27% (12/45) of the neuromas. Among the 23 neuromas with enhanced images, 78% (18/23) showed enhancement. Heterogeneity on T2-WIs and enhancement ratios were significantly different between the asymptomatic and symptomatic neuroma groups (p < 0.05). The multivariate analyses indicated that heterogeneity on T2-WIs was an independent factor associated with symptomatic neuromas (p < 0.001). CONCLUSIONS: Heterogeneity on T2-WIs could be a predictive indicator for symptomatic neuromas in lower extremity amputees. KEY POINTS: • Amputation neuromas are classified as either end-bulb or spindle-type. They can show enlarged fascicles, dark outer rims, and enhancement. • Heterogeneity on T2-weighted images could be a predictive indicator for symptomatic neuromas. • Predicting the symptomatic neuroma on MRI would help in effective management of stump pain.

An ultrasonographic and electromyographic evaluation of jumping stump possibly due to a neuroma in a patient with transradial amputation: A case report.

BACKGROUND AND OBJECTIVE: Jumping stump is an uncommon movement disorder characterized by involuntary movements and severe neuropathic pain in the stump. The pathophysiology and etiology of this phenomenon have not yet been clearly elucidated, and unfortunately, no proven treatment with successful recovery exists. This report aims to describe a severe painful jumping stump, possibly due to neuromas, in a traumatic transradial amputee. MATERIALS AND METHOD: We performed ultrasound examination of the painful stump depicted neuroma. Electromyographic evaluation of the stump revealed arrhythmic motor unit action potentials (MUAPs) with normal duration and amplitude; other movement disorders, such as myokymia and fasciculations, were excluded. Ultrasound should be preferred to magnetic resonance imaging (MRI) for evaluation of stumps in patients with painful stump because MRI may not be helpful due to motion artefacts. The involuntary movements ceased after surgical excision of the neuroma following failure of conservative treatments. CONCLUSION: This report confirms that neuromas are clearly associated with jumping stump. Ultrasonographic and electromyographic assessments are necessary to reveal the features of this pathology for treatment planning.

Stump appendicitis: a myth that can become reality.

Stump appendicitis is a rare etiology of acute lower right quadrant abdominal pain often forgotten in the emergency room (ER). The Mac Burney scar or a previous laparoscopic appendectomy always rule out the eventuality of appendicitis and mislead management. Advanced imaging tools are more than compulsory to help correct the diagnosis. Computed tomography (CT) scan is the option of choice that may be replaced if unavailable by simple ultrasound examination. The treatment is mainly surgical. We report the case of a stump appendicitis occurring 12 years after laparoscopic appendectomy in an 18-year-old girl. The diagnosis was based on consistent clinical signs and conclusive radiological data. A successful completion appendectomy was performed with good outcome.

Easy Technique for Radiographic Evaluation of Stump-socket Fit in Below-knee Amputees.

BACKGROUND: The alignment of a prosthesis affects the way load is transferred to the stump through the socket; this is critically important for its comfort and function. The aim of the study was to assess the value of radiopaque materials in evaluation of stump-socket fit in people with below-knee amputation. MATERIAL AND METHODS: Thirty-two amputees (skin breakdown group) had cutaneous lesions in the stump, and another 26 amputees (control group) had no lesion in the stump after training with their prosthesis. Metallic markers were attached to weight-bearing points in the internal socket. X-rays were taken in the antero-posterior and lateral projections. RESULTS: In the antero-posterior view, the weight-bearing points of the stump did not correspond to the metallic markers placed over the patellar tendon and the tibial tuberosity points in the socket in 78.1% of the 32 amputees in the skin breakdown group. This malalignment was present in 42.3% of the 26 amputees in the control group (Pearson Chi-Square, p<0.007). In the lateral view, in 65.6% of the 32, the weight-bearing points of the stump did not correspond to the metallic markers placed over the patellar tendon and the tibial tuberosity points in the socket. This malalignment was noted in 23.1% of the 26 patients in the other group (Pearson Chi-Square, p<0.002). CONCLUSIONS: 1. The conflict between the prosthesis and residual limb is the cause of skin disruption at different sites of the stump and can be successfully treated by prosthetic socket modification. 2. Efforts should be made to systematically identify any discrepancies between the stump and the soc-ket. 3. Correct adaptation of the prosthesis to the weight-bearing points of the stump will offer clinicians the possibility of quantification and visualization of this interaction using simple radiographic techniques.

A Framework for Measuring the Time-Varying Shape and Full-Field Deformation of Residual Limbs Using 3-D Digital Image Correlation.

Effective prosthetic socket design following lower limb amputation depends upon the accurate characterization of the shape of the residual limb as well as its volume and shape fluctuations. OBJECTIVE: This study proposes a novel framework for the measurement and analysis of residual limb shape and deformation, using a high-resolution and low-cost system. METHODS: A multi-camera system was designed to capture sets of simultaneous images of the entire residuum surface. The images were analyzed using a specially developed open-source three-dimensional digital image correlation (3D-DIC) toolbox, to obtain the accurate time-varying shapes as well as the full-field deformation and strain maps on the residuum skin surface. Measurements on a transtibial amputee residuum were obtained during knee flexions, muscle contractions, and swelling upon socket removal. RESULTS: It was demonstrated that 3D-DIC can be employed to quantify with high resolution time-varying residuum shapes, deformations, and strains. Additionally, the enclosed volumes and cross-sectional areas were computed and analyzed. CONCLUSION: This novel low-cost framework provides a promising solution for the in vivo evaluation of residuum shapes and strains, as well as has the potential for characterizing the mechanical properties of the underlying soft tissues. SIGNIFICANCE: These data may be used to inform data-driven computational algorithms for the design of prosthetic sockets, as well as of other wearable technologies mechanically interfacing with the skin.

Iliac crest apophysis transfer to treat stump overgrowth after limb amputation in children: case series and literature review.

PURPOSE: Stump overgrowth is the main problem of limb amputation in children. Many surgical procedures have been developed to overcome the problem, but all have shown inconsistent results. The only surgical procedure that has been successful in preventing overgrowth is capping of the amputated limb with a cartilaginous cap taken from the amputated limb, usually from the head of fibula. A donor site is not available in revision cases. Iliac crest apophysis transfer was suggested to treat the condition, but has never been previously reported. The purpose of this study is to review the results of iliac crest apophysis transfer to prevent stump overgrowth. METHOD: Five children with amputation stump overgrowth underwent iliac apophyseal transfer to cap the resection site of the overgrowth. RESULTS: Retrospective review showed that three of the five suffered recurrent stump overgrowth two to four years after the index surgery. All three were revised again. One patient was lost to follow-up. CONCLUSION: Although many studies showed capping of the stump with cartilaginous cap to be successful in preventing stump overgrowth, iliac crest apophysis transfer was only successful in one of four cases available to follow-up (25%). This is not a reliable enough method to be used routinely.

Correlates of Residual Limb Pain: From Residual Limb Length and Usage to Metabolites and Activity in Secondary Somatosensory Cortex.

Most recent studies attribute residual limb pain to peripheral pathological changes of the stump. However, in this paper, we focus on its associations with the residual limb length, usage, as well as the metabolic and functional alterations of the brain. The secondary somatosensory cortex (S2), one important area involved in pain intensity discrimination, was selected as the region of interest. Twenty-two upper-limb amputees were recruited and divided into two groups, i.e., amputees with residual limb pain (9/22) and without residual limb pain (13/22). The residual limb length, usage, as well as the metabolite concentration, resting-state activity and BOLD responses to the tactile stimulation in the contralateral S2, were compared between the two groups and correlated with the pain intensity. The amputees with residual limb pain showed significantly shorter length and less usage of the residual limb than the amputees without residual limb pain, and the pain intensity was significantly negatively correlated with the residual limb length and usage. In addition, the pain intensity was significantly correlated with the tNAA/tCr ratio, resting-state fALFF in the slow-4 band, and BOLD response to the tactile stimulation in the contralateral S2, although there were no significant group differences. Regression analysis suggested that residual limb pain is associated with shorter residual limb length and less residual limb usage.

Radiological comparison of conventional versus modified sauvé-kapandji procedure with stabilization of the proximal ulnar stump using the extensor carpi ulnaris tendon: A retrospective case-control study.

The Sauvé-Kapandji procedure is a reliable option for patients with various disorders of the distal radioulnar joint (DRUJ). However, postoperative pain over the proximal ulnar stump frequently develops during forearm rotation or when lifting heavy objects, although many clinically satisfactory results have been reported. This stump pain has been suggested to result from dynamic instability of the proximal ulnar stump. Several types of tenodesis have recently been performed simultaneously with the Sauvé-Kapandji procedure to stabilize the proximal ulnar stump and thus relieve the associated pain. Although satisfactory outcomes of these stabilization procedures have been reported, correlations of the residual symptoms and radiographic findings between the conventional method and the modified method. Additionally, the mechanism of pain relief remains unclear.To elucidate the cause of proximal ulnar stump pain, the clinical results and radiographic changes were compared between 2 treatment groups in which different Sauvé-Kapandji procedures had been performed. Twenty-four wrists with distal radioulnar disorders, all of which had undergone Sauvé-Kapandji procedures, were retrospectively classified into 2 groups according to the procedure. Group A (13 wrists) was treated by the conventional surgical procedure, in which the proximal ulnar stump is not stabilized. Group B (11 wrists) was treated by the modified method, in which the proximal ulnar stump is stabilized by tenodesis with the extensor carpi ulnaris tendon. Wrist pain, proximal ulnar stump pain, ranges of forearm pronation/supination, and grip strength were investigated. The ulnar distance, ulnar gap, interosseous distance, and dorsopalmar distance were measured on both resting and dynamic radiographs.Stump pain was recognized in 6 wrists in group A and 0 in group B. However, no substantial differences in the other clinical findings or 4 radiographic parameters were found between the 2 groups.These findings suggest that stabilization of the proximal ulnar stump cannot correct either dorsal ulnar deviation or dorsal displacement of the radius. Therefore, proximal ulnar stump pain may not be caused by either radial or dorsal deviation of the proximal ulnar stump but instead by other dynamic factors.

Intra-arterial fibrinolysis for the management of acute ischemia on a below-knee amputation stump. Case report.

Preservation of the knee joint has enormous advantages in terms of mobility and rehabilitation of an amputee. Any cause of breakdown requiring revision to an above-knee amputation is a major setback because it reduces the patient's rehabilitative potential. We report a case of intra-arterial thrombolysis use to save a below-knee amputation stump with acute ischemia. A 56-year-old man who sought the emergency department with 1-day history of acute pain on his right below-knee stump. The angiography confirmed popliteal artery occlusion. Pharmacomechanical thrombectomy, with Aspirex (rotational catheter to restore blood flow in occluded vessel, by removing occlusion material from the vessel) and recombinant tissue plasminogen activator, was performed. After 9 years of follow-up the patient remained asymptomatic, capable of independent ambulation with prosthetic limb. Intra-arterial fibrinolysis seems to be a safe and effective treatment for cases of acutely ischemic amputation stump.

Intense Focused Ultrasound Preferentially Stimulates Transected Nerves Within Residual Limbs: Pilot Study.

Objective: Identifying pain generators in tissue deep in the skin can require uncomfortable, complicated, and invasive tests. We describe pilot studies testing the hypothesis that ultrasound image-guided, intense focused ultrasound (ig-iFU) can noninvasively and differentially stimulate the end of transected nerves in the residual limbs of amputee patients. Design: We applied iFU to the transected nerve ending as individual pulses with a length of 0.1 seconds using a carrier frequency of 2.0 MHz. After targeting, we gradually increased the iFU intensity to reach consistent patient-reported stimulation of the transected nerve ending. We also stimulated the proximal nerve, tissue near the nerve ending, and the intact contralateral nerve. We described the resulting sensations and correlated the results of the study participant's pre-iFU study responses to phantom and residual limb pain questionnaires. Results: iFU spatial and temporal average intensity values between 16 W/cm2 and 433 W/cm2 that were applied to the transected nerve ending and proximal nerve elicited sensations, including phantom limb sensations, while the same intensity applied to control tissue centimeters away from the nerve ending, or to the intact nerve on the contralateral limb, did not. Two out of 11 study participants reported only mild and transient pain created by iFU stimulation. Successful iFU intensity values correlated with neither phantom nor residual limb pain scores. Conclusions: Transected nerves had greater sensitivity to iFU stimulation than ipsilateral and contralateral control tissue, including intact nerve. These results support the view that ig-iFU may one day help physicians identify deep, tender tissue in patients who report experiencing pain.

Measurement properties and usability of non-contact scanners for measuring transtibial residual limb volume.

BACKGROUND: Non-contact scanners may have potential for measurement of residual limb volume. Different non-contact scanners have been introduced during the last decades. Reliability and usability (practicality and user friendliness) should be assessed before introducing these systems in clinical practice. OBJECTIVES: The aim of this study was to analyze the measurement properties and usability of four non-contact scanners (TT Design, Omega Scanner, BioSculptor Bioscanner, and Rodin4D Scanner). STUDY DESIGN: Quasi experimental. METHODS: Nine (geometric and residual limb) models were measured on two occasions, each consisting of two sessions, thus in total 4 sessions. In each session, four observers used the four systems for volume measurement. Mean for each model, repeatability coefficients for each system, variance components, and their two-way interactions of measurement conditions were calculated. User satisfaction was evaluated with the Post-Study System Usability Questionnaire. RESULTS: Systematic differences between the systems were found in volume measurements. Most of the variances were explained by the model (97%), while error variance was 3%. Measurement system and the interaction between system and model explained 44% of the error variance. Repeatability coefficient of the systems ranged from 0.101 (Omega Scanner) to 0.131 L (Rodin4D). Differences in Post-Study System Usability Questionnaire scores between the systems were small and not significant. CONCLUSION: The systems were reliable in determining residual limb volume. Measurement systems and the interaction between system and residual limb model explained most of the error variances. The differences in repeatability coefficient and usability between the four CAD/CAM systems were small. Clinical relevance If accurate measurements of residual limb volume are required (in case of research), modern non-contact scanners should be taken in consideration nowadays.

Intra-arterial fibrinolysis for the management of acute ischemia on a below-knee amputation stump. Case report / Fibrinólise intra-arterial para tratamento da isquemia aguda em coto de amputação infrapatelar. Relato de caso

ABSTRACT Preservation of the knee joint has enormous advantages in terms of mobility and rehabilitation of an amputee. Any cause of breakdown requiring revision to an above-knee amputation is a major setback because it reduces the patient's rehabilitative potential. We report a case of intra-arterial thrombolysis use to save a below-knee amputation stump with acute ischemia. A 56-year-old man who sought the emergency department with 1-day history of acute pain on his right below-knee stump. The angiography confirmed popliteal artery occlusion. Pharmacomechanical thrombectomy, with Aspirex (rotational catheter to restore blood flow in occluded vessel, by removing occlusion material from the vessel) and recombinant tissue plasminogen activator, was performed. After 9 years of follow-up the patient remained asymptomatic, capable of independent ambulation with prosthetic limb. Intra-arterial fibrinolysis seems to be a safe and effective treatment for cases of acutely ischemic amputation stump.

RESUMO A preservação da articulação do joelho tem grandes vantagens para a mobilidade e a reabilitação de um amputado. Qualquer causa que exija revisão para uma amputação acima do joelho é um grande revés, porque reduz o potencial de reabilitação do paciente. O objetivo aqui foi descrever o uso de trombólise intra-arterial para salvar um coto de amputação abaixo do joelho com isquemia aguda. Homem, 56 anos, procurou pronto atendimento de nosso hospital com histórico de 1 dia de dor aguda em seu coto de amputação infrapatelar direito. A angiografia confirmou oclusão da artéria poplítea. Foi realizada trombectomia farmacomecânica com Aspirex (cateter rotativo para restabelecer o fluxo sanguíneo em vasos ocluídos, removendo material de oclusão do vaso) e ativador do plaminogênio tecidual recombinante. Após 9 anos de seguimento, o paciente permanecia assintomático, capaz de deambulação independente com membro protético. A fibrinólise intra-arterial parece ser um tratamento seguro e eficaz para casos selecionados de coto de amputação com isquêmica aguda.

Structural changes in the thigh muscles following trans-femoral amputation.

INTRODUCTION: Early ambulation is the principal objective in trans-femoral amputees. Postamputation modifications complicate the rehabilitation process due to a reduced control at the interface between stump and prosthesis. The aim of this study is to determine whether magnetic resonance imaging depicts the amount of fatty degeneration of the thigh muscles after trans-femoral amputation (TFA). METHODS: A total of 12 patients following a TFA on the basis of a bone neoplasm or metastasis with an evaluable postoperative MRI were identified. Using the Goutallier classification, the fatty degeneration of the thigh muscles was analyzed in the middle (M) and at the distal end (E) of the residual limb at T1 (10.6 months) and T2 (25.6 months). RESULTS: Analysis at two different levels showed different grades of fatty degeneration of thigh muscles after TFA at T1 and T2. Comparing fatty degeneration at both levels of the stump, the quadriceps femoris revealed a significant change (p = 0.01) at T1 and M. sartorius and adductor (p = 0.02) at T2. CONCLUSIONS: MRI is an excellent diagnostic tool to evaluate fatty degeneration after TFA. The highest amount of fatty degeneration of the quadriceps muscle was monitored within the first 10 months. Early physiotherapy is important to strengthen the remaining stump muscles during rehabilitation.