Distal Limb Research Articles (Page 1)

Intravenous regional limb perfusion (IVRLP) of antibiotics is a therapeutic method used to treat distal limb infections in horses. The objectives of this study were to determine the pharmacokinetic parameters and tolerance of sodium benzylpenicillin (NaBP) administered via IVRLP; to compare the feasibility, tolerance, and efficacy of performing IVRLP on a flexed limb versus a weightbearing limb; and to predict the efficacy of IVRLP using gentamicin or NaBP. A prospective crossover study was conducted with six horses, each undergoing four phases of antibiotic infusion (gentamicin at 2.2mg/kg vs. NaBP at 7,333 IU/kg of BP) and limb positioning (weightbearing vs. flexed). Each antibiotic administration was followed by serial synovial and blood sampling to assess antibiotic concentrations. Inflammation and sensitivity to palpation were evaluated at both the injection site and the sampled joint. A pharmacokinetic/pharmacodynamic analysis was carried out to predict the efficacy of IVRLP by estimating area under the concentration-time curve to minimum inhibitory concentration (AUC/MIC) index values for various minimum inhibitory concentrations (MICs). High synovial concentrations of NaBP and gentamicin were achieved, with notable variability between horses. NaBP IVRLP was well tolerated, although cephalic vein inflammation scores were significantly higher following NaBP infusion than gentamicin (p = 3.4 × 10- 11). For all horses and both antibiotics, synovial antibiotic exposures were significantly greater in weightbearing limbs than in flexed limbs (p = 0.04 and 0.02 for NaBP and gentamicin, respectively). Cephalic vein inflammation scores were also significantly lower in weightbearing limbs than in flexed limbs (p = 2.5 × 10- 5). In terms of predicted efficacy, a daily dose of 2.2mg/kg gentamicin should be adequate to treat synovial infections involving Escherichia coli or Staphylococcus aureus, including resistant strains. For NaBP, a daily or every-other-day dose of 7,333 IU/kg of BP should be adequate to treat infections caused by Streptococcus equi and sensitive Staphylococcus aureus. These findings suggest that daily IVRLP with NaBP (7,333 IU/kg of BP) could be an effective treatment for distal limb infections caused by susceptible bacteria with a MIC of ≤ 2µg/mL, with only mild local inflammation at the injection site. IVRLP with 2.2mg/kg gentamicin appears effective for treating infections involving susceptible bacteria with an MIC of ≤ 16µg/mL. Performing IVRLP on a weightbearing limb resulted in higher antibiotic exposure in the metacarpophalangeal joint and better tolerance than the flexed limb method.

Cutaneous wound repair is tightly regulated by numerous signaling pathways that coordinate a multiphased response. The repair process includes a proliferative phase that forms granulation tissue at the wound base and re-epithelialization of the wound surface. Two of the signaling pathways that regulate the proliferative phase are Wnt/β-catenin and Notch, stimulating the proliferation of keratinocytes and fibroblasts, respectively. While ephrin-Eph signaling pathways also induce keratinocyte proliferation, their contribution to cutaneous wound repair is less defined. In distal limb wounds on horses, the proliferative phase is often characterized by the formation of excessive granulation tissue that delays healing by impeding keratinocyte migration from the wound margin. Comparison of normal and aberrant healing makes distal limb horse wounds well-suited for defining molecular mechanisms that regulate repair during the proliferative phase and identifying targets that promote healthy wound healing. We hypothesize that ephrin-Eph signaling pathways that stimulate keratinocyte proliferation provide an unexplored but effective target for accelerating re-epithelialization in distal limb wounds of the horse. As re-epithelialization is a key to physiologic healing in many mammals, we further hypothesize that ephrin-Eph signaling pathways offer targets for enhanced wound repair in humans.

Exuberant granulation tissue (EGT) is a second intention wound healing disorder. It commonly occurs in the distal limb of horses. EGT causes significant increase in the duration and cost of treatment, potentially leading to the decision not to pursue treatment and euthanize the patient. The underlying pathomechanisms of this fibroproliferative disorder remain unclear, particularly in terms of collagen composition and the association between myofibroblasts and blood vessels. This study investigated the collagen composition in naturally occurring EGT following trimming in 19 horses (EGT group). In both the superficial and deep wound beds of EGT-affected horses, the collagen distribution was assessed and compared to control wounds (n = 6 horses, control group, punch biopsies) using histology. Immunofluorescence was performed to colocalize activated alpha smooth muscle actin-positive myofibroblasts in EGT as well as angiogenic markers. Our histological findings showed significantly higher amounts of immature collagen (type III) in the superficial and deep regions of EGT compared to the controls while the total amount of collagen in both groups did not differ significantly. In EGT, occluded microvessels and endothelial cell hypertrophy were present in the deep layer and myofibroblasts were ubiquitously found in the whole wound bed. Markers for intermediate filaments were reduced in the superficial region. In conclusion, collagen composition in EGT differed significantly from control wounds, indicating tissue immaturity. Consequently, promoting tissue maturation towards a more mature ECM composition could serve as a valuable target for future therapeutic interventions enabling better regeneration.

Introduction: Acute limb ischemia (ALI) is a common and serious complication in patients undergoing femoral veno-arterial extracorporeal membrane oxygenation (VA-ECMO), largely due to compromised distal limb perfusion. This study evaluates the role of femoral-femoral crossover shunts in maintaining distal limb perfusion in patients on VA-ECMO. Hypothesis: Femoral-femoral crossover shunting during femoral VA-ECMO significantly increases distal limb perfusion and may reduce the incidence of ALI. Methods: We conducted a retrospective review of all patients who underwent femoral VA-ECMO at our tertiary care institution between December 2024 and May 2025. Patients were included if they received femoral-femoral crossover shunts and underwent lower extremity duplex ultrasound during ECMO. Collected variables included patient demographics, cannulation technique, shunt characteristics, and duplex ultrasound measurements—peak systolic velocity and volume flow—in the superficial femoral artery (SFA), popliteal artery (PA), and posterior/anterior tibial arteries (PT/AT). Flow velocity and volume were measured in the cannulated limb with the shunt on and off, as well as in the uncannulated limb. Descriptive statistics were used to analyze associations with distal perfusion parameters. Results: Thirteen patients underwent femoral VA-ECMO with distal reperfusion during this period. The mean age was 47 years, and 53% of patients were male. Three patients had complete duplex ultrasound data. Mean flow volumes were higher when the shunt was open: SFA flow volume increased by 218% (from 47.2 to 150.3 mL/min), PA by 161% (25.0 to 66.7 mL/min), and PT/AT by 27% (9.5 to 12.1 mL/min). In the cannulated limb, the shunt increased SFA peak systolic velocity by 38% (25.3 to 35.0 cm/s), PA velocity by 21% (25.3 to 30.7 cm/s), and PT/AT velocity by 19% (19.2 to 23.0 cm/s). In the uncannulated limb, mean SFA, PA, and PT/AT velocities were 66.3, 70.0, and 20.0 cm/s, respectively, with corresponding flow volumes of 142.3, 94.0, and 6.2 mL/min. None of the patients in this cohort developed clinical signs of acute limb ischemia. Conclusion: Femoral-femoral crossover shunting during femoral VA-ECMO appears to improve distal limb perfusion, with notable increases in both velocity and flow. These findings suggest that crossover shunting may serve as a practical adjunct to mitigate ischemic complications in patients undergoing femoral cannulation for ECMO support.

(1) Background: Cone beam computed tomography (CBCT) is increasingly used in equine practice to diagnose musculoskeletal injuries, including fractures in the distal limb. However, limited detail in the thick cortical bone of the metacarpus/metatarsus hinders accurate diagnosis. In human medicine, the addition of aluminum filters (AF) enhanced image quality while reducing radiation exposure. This study aimed to evaluate the effect of AF on image quality in CBCT scans of equine distal limbs. (2) Methods: Adult equine cadaver limbs were scanned with a mobile CBCT unit using varying tube currents (10–100 mA) and AF (13–25 mm). Two independent experts assessed the image quality using a four-point visual grading scale, focusing on cortical bone detail and artifacts. (3) Results: Higher tube currents generally improved image quality, but no filter was beneficial for the metacarpal/metatarsal regions. For the proximal phalanx, thicker AF (19–25 mm) improved image quality without significantly increasing the required tube current. (4) Conclusions: The optimal balance between image quality and radiation exposure using the O-arm® CBCT system for equine distal limbs was a tube current of 50 or 64 mA without filtration for the metacarpus/metatarsus, while a tube current of 50 mA with a 19–25 mm AF provided the best image quality for the proximal phalanx.

Ipsilateral contraction increases map area and decreases motor threshold for contralateral hand muscle.

Post-traumatic knee osteoarthritis with malunited regenerated distal femur and limb length discrepancy: A case report of computer-assisted navigation total knee arthroplasty.

We report a sibling case of progressive muscle weakness beginning in their 40s. The younger brother was initially suspected to have spinal muscular atrophy based on electromyography findings, but no SMN1 gene deletion was identified. Whole-exome sequencing in the siblings detected a heterozygous nonsynonymous mutation, c.577G>A (p.Ala193Thr), located in the actin-binding domain (ABD) of the filamin C (FLNC) gene. Muscle weakness of a sibling started in the proximal lower limbs and gradually progressed to the distal lower limbs, trunk, and upper limbs. Muscle MRI showed marked involvement of the medial and posterior thigh muscles, gastrocnemius, and soleus muscles, with relative sparing of the muscles of rectus femoris, gracilis, and tibialis anterior. These findings suggest a characteristic pattern of muscle involvement associated with this FLNC-ABD mutation.

Non-invasive brain stimulation such as transcranial direct current stimulation over the primary motor cortex (M1) and supplementary motor area (SMA) during gait can positively affect gait ability in patients after stroke; however, the frequency-specific modulatory effects of rhythmic brain stimulation over the M1 and SMA on the oscillatory neural drives during gait remain unclear. Therefore, we investigated the effects of the alpha and beta to low-gamma oscillatory transcranial direct current stimulation (otDCS) over the M1 and SMA on the oscillatory neural drives to lower limb muscles during gait, using coherence analysis of paired surface electromyography, in 32 healthy young adults. Experiments involved treadmill gait measurements, comprising pre-stimulation gait, gait with otDCS in three stimulation conditions (10-Hz otDCS, 30-Hz otDCS, and sham stimulation) over the M1 and SMA, and post-stimulation gait. Although the 10-Hz otDCS and sham stimulation induced no effects, the 30-Hz otDCS over the M1 and SMA significantly increased the average values of the tibialis anterior intramuscular coherence and vastus medialis and lateralis intermuscular coherence, respectively, in the 20-40Hz (beta to low-gamma) frequency bands during post-stimulation gait compared to the pre-stimulation gait. Therefore, beta to low-gamma otDCS over the M1 and SMA during gait selectively increased the oscillatory neural drives to distal and proximal lower limb muscles, respectively. This study provides novel evidence that beta to low-gamma rhythmic brain stimulation could be an effective rehabilitation strategy for improving gait ability in patients with central nervous system disorders, with specific deficits in the M1 or SMA.

To demonstrate the feasibility and clinical utility of standing CT in ruminant species. Medical records of ruminants that underwent standing CT from January 2019 through August 2025 were reviewed. 9 cases met inclusion criteria. Cases included bovine (n = 7) and small ruminants (2). There were 7 males and 2 females. Ages ranged from 3 to 84 months. Weights ranged from 83 to 600 kg. Cases presented for a head tilt (n = 4), a submandibular mass (1), head shaking (1), and lameness (3). Anatomic regions of interest imaged with CT included the head (n = 6) and distal limbs (3). A final imaging diagnosis was achieved in 8 of 9 cases. Diagnosis included otitis media (n = 4), mandibular lymph node abscess (1), stenosis of retroarticular foramen (1), septic arthritis (1), and fracture (1). Animals tolerated standing CT imaging well, and no complications were encountered. Sedated standing CT of the head and distal limbs is feasible in ruminants and may be an option in patients that are amenable to a standing imaging procedure.

Background/Objectives: The diagnosis of acute compartment syndrome (ACS) of the extremities is typically based on subjective clinical signs and symptoms, highlighting the need for user-friendly diagnostic tools to improve accuracy and reliability. This study evaluates the performance of two commercial devices, the MY01® continuous pressure monitoring system and the Moxy Monitor near-infrared spectroscopy-based system, against a reference standard of continuous intracompartmental pressure (ICP) monitoring in a preclinical ACS model. Methods: ACS was induced in the anterior compartment of the distal hind limb in eight Yorkshire pigs using a balloon displacement model. ICP was incrementally elevated and maintained for four hours at >30 mmHg above mean arterial pressure. This was followed by balloon deflation and reperfusion. Final assessments were performed at 24 h post-injury. ICP measurements from the MY01® and muscle oxygen saturation (SmO2) data from the Moxy Monitor were compared to reference ICP measurements. Histologic analysis of muscle tissue was performed to assess the severity of necrosis. Results: The MY01® provided accurate ICP measurements, with a mean bias of 2.21 ± 18.77 mmHg during pre-ischemia, 4.86 ± 10.43 mmHg during reperfusion, and 4.69 ± 3.28 mmHg 24 h post-injury, compared to reference probes. Correlation at 24 h post-injury was (r = 0.86, R2 = 0.73, p < 0.0001). In contrast, the Moxy Monitor failed to detect significant differences in SmO2 between injured and control limbs at 24 h post-injury, despite pronounced ICP differences. Our volumetric displacement ACS model demonstrated its efficacy as a testing platform by allowing for controlled, incremental elevation in ICP and sustaining elevated ICP levels after 24 h. Histologic evaluation confirmed extensive muscle damage, including edema and necrosis. Conclusions: The MY01® provides accurate, continuous ICP monitoring, supporting its clinical utility in ACS diagnosis. However, the use of near-infrared spectroscopy-based systems such as the Moxy Monitor for ACS diagnosis and management should continue to be critically scrutinized.

Glomus tumor (GT) is a mesenchymal neoplasm composed of modified perivascular cells exhibiting smooth muscle-like features, resembling those of the normal glomus body. The lesions often occur in areas rich in glomus vascularis, most of which occur in the distal limbs, while the sellar GT is extremely rare. Here, we present a case of primary sellar GT harboring a BRAF K601E mutation, identified through next-generation sequencing. The patient has been followed for 10years, with tumor recurrence noted in the fourth year post-surgery. This report highlights the histological features, biological behavior, clinical manifestations, and prognosis of sellar GTs with a BRAF K601E mutation. Literature review suggests that determining the biological behavior of sellar GTs remains challenging, complicating diagnosis and treatment planning. We summarize the clinical and pathological characteristics of sellar GTs and propose considerations for pathological diagnosis based on our findings.

Abstract A 4‐year‐old, neutered, male red fox (Vulpes vulpes) was referred for evaluation of a 1‐week history of inappetence and lethargy, unresponsive to outpatient care. Abdominal ultrasound revealed a pyloric linear foreign body extending into the descending duodenum with pneumoperitoneum and peritoneal effusion. Emergent exploratory laparotomy confirmed a mesenteric duodenal perforation, located aboral to the distal right limb of the pancreas. Foreign material was manipulated into the stomach and removed via gastrotomy. The perforation and surrounding devitalised tissue were excised using a 6‐mm Baker's biopsy punch, and the site was closed primarily. The patient was discharged 8 days postoperatively. Superficial incisional dehiscence was treated on an outpatient basis 2 weeks following surgery. Thirty‐eight days postoperatively, the patient was clinically normal with complete incisional healing. Punch biopsy debridement and primary repair of a focal proximal duodenal perforation was well‐tolerated and not associated with any significant short‐ or long‐term complications.

BackgroundTotal Body PET/CT is increasingly used in clinical practice, but its benefits for lung cancer staging are not fully established. This study aimed to evaluate the impact of Total Body PET/CT on lung cancer staging compared to traditional Whole-Body PET/CT.ResultsAmong the 763 patients, 289 (37.9%) had stage IV disease, with 96 (33.2%) showing limb metastases, including those in the lower limbs (legs) or also the upper limbs (arms). Compared to Whole-Body PET/CT, Total Body PET/CT detected additional metastases in 60.4% (58/96) of patients with limb metastases, representing 20.1% (58/289) of all stage IV patients. These included 96 bone and 43 muscle metastases. In patients with isolated limb metastases (n = 31), Total Body PET/CT detected additional metastases in 13 (41.9%) compared to Whole-Body PET/CT, altering tumor staging in only one patient (0.3% of stage IV patients). In those with multiple limb metastases (n = 65), Total Body PET/CT detected additional metastases in 45 (69.2%), but staging remained unchanged. Distal limb metastasis was strongly associated with concurrent bone (OR = 8.288, 95%CI: 3.642–18.861) and muscle metastases outside the limb (OR = 3.911, 95%CI: 1.624–9.417) (both P < 0.001). Additionally, Total Body PET/CT detected acute arthritis in 193 (25.3%) patients and benign lesions (e.g., varicose veins, neurogenic tumors, lipomas, fractures) in 68 (8.9%) compared to Whole-Body PET/CT.ConclusionWhole-Body imaging is sufficient to meet the clinical staging requirements for lung cancer. Although Total Body PET/CT detects more distal metastases in approximately 20% of stage IV lung cancer patients, it led to stage shift in only one patient and 0% change in the oncologic treatment.

Recent prospective research indicates that unipedal stance time (UST) of < 15s in middle/older adults increases their risk of repetitive falls within 5 to 10 years. To determine the extent that clinical measures of three physiologic capacities, peripheral afferent acuity, processing speed, and proximal frontal plane strength, are responsible for UST. UST, distal lower limb clinical vibratory sense, short latency go/no-go accuracy using ReacStick, and lateral plank time, were evaluated in a cohort (n = 172, 51% female, age 64.8 +/- 9.6 years) with diabetic neuropathy (n = 31), cirrhosis (n = 94), and no known neurologic disease (n = 47) using age, body mass index (BMI), sex, and medication number as covariates. Multivariate analyses demonstrated that the three variables separately, and as a composite variable (vibration time + reaction accuracy/2 + lateral plank time), were associated with UST (adjusted R2 = 0.66 and 0.65, respectively) for the entire group, and for diabetic neuropathy, cirrhosis, and no known disease groups separately (adjusted R2 = 0.59, 0.60, and 0.68, respectively). The composite variable also classified participants into those with UST > and < 15s (receiver operator characteristics area under the curve (AUC) = 0.92 (95% CI = 0.88, 0.96)). These findings allow clinicians to identify specific physiologic deficits and develop targeted intervention strategies to improve UST. Clinical estimates of three physiologic capacities predict almost 2/3 of UST variability in middle/older people, rendering age, BMI, sex, and medication number less relevant.

Background and Objectives: Distal upper limb injuries are frequent in winter sports, but their functional impact is often underestimated. This study aimed to describe the epidemiology, mechanisms, and risk factors for injuries involving the forearm, wrist, hand, and fingers sustained during two consecutive winter seasons in the Italian Dolomites. Materials and Methods: All adult and willing patients presenting to the Emergency Department of Brixen Hospital after ski- or snowboard-related accidents between December 2023 and March 2025 completed a standardized 23-item questionnaire on demographics, experience level, environmental factors, equipment, and trauma mechanism. For the aim of this study only distal upper limb injuries were extracted and analyzed. Statistical analyses compared fracture versus non-fracture injuries, “good” versus “bad” fractures (AO classification and surgical complexity), and isolated ulnar collateral ligament (UCL) injuries. Results: A total of 195 patients were analyzed: 96 (49.2%) sustained a fracture and 33 (16.9%) presented with isolated UCL lesions. Fractures occurred more frequently on blue slopes (56.2% vs. 33.3%, p < 0.001), whereas non-fracture injuries predominated on red and off-piste slopes. Age, BMI, and skill level did not differ significantly between groups. Surgically classified complex distal forearm fractures were significantly more frequent in females (p < 0.005) but were not associated with environmental factors. UCL injuries occurred mainly on red slopes (54.5%) and were often related to pole entrapment during falls. None of the injured patients reported the use of protective wrist or thumb supports. Conclusions: Distal upper limb injuries are a common pattern of alpine sports trauma, with wrist fractures and skier’s thumb being predominant lesions. Low-speed falls on easy slopes are associated with wrist fractures, while UCL injuries are linked to intermediate slopes. Preventive strategies should include fall technique education, protective gloves, and improved pole ergonomics.

Fractures of the distal limb in Thoroughbred racehorses primarily occur because of accumulation of bone microdamage from high-intensity training. Mathematical models of subchondral bone adaptation of the third metacarpal lateral condyles are capable of approximating existing data for Thoroughbred racehorses in training or at rest. To improve upon previous models, we added a dynamic resorption rate and microdamage accumulation and repair processes. Our ordinary differential equation model simulates the coupled processes of bone adaptation and microdamage accumulation, and is calibrated to data on racehorses in training and rest. Sensitivity analyses of our model suggest that joint loads and distances covered per day are among the most significant parameters for predicting microdamage accumulated during training. We also use the model to compare the impact of incrementally increasing training programmes as horses enter training from a period of rest, and maintenance workloads of horses that are race fit on bone adaptation. We find that high-speed training accounts for the majority of damage to the bone. Furthermore, for horses in race training, the estimated rates of bone repair are unable to offset the rate of damage accumulation under a typical Australian racing campaign, highlighting the need for regular rest from training.

Distal limb ischemia from jellyfish envenomation: A case report

Radiographic Studies of Distal Limb Fractures in Working Equine: A Clinical Study.

ObjectiveTo evaluate the effect of heel elevation on in vivo measurement of stiffness gradients by means of acoustoelastography in the digital flexor tendons of clinically normal horses.Animals15 clinically normal horses.ProceduresFor each horse, stiffness gradient index (SGI) for superficial digital flexor tendons (SDFT) and deep digital flexor tendons (DDFT) were evaluated in both forelimbs at 0, 4 and 8 degrees of heel elevation. Acoustoelastography (AEG) was used for data acquisition at three sites, approximately 6, 12, and 18 cm distal to the accessory carpal bone in the metacarpal region. Lifting the contralateral limb during image acquisition resulted in the application of load and the subsequent SDFT and DDFT deformation required. The effects of loaded versus unloaded digital flexor tendons and right-to-left limb symmetry on SGI at three regions in the metacarpal region were further evaluated. Changes in angulation of the metacarpophalangeal, proximal interphalangeal, and distal interphalangeal (DIP) joints in conjunction with the palmar angle (PA) of the distal phalanx and toe angle (TA) were measured radiographically at 0, 4 and 8 degrees of heel elevation to approximate trends in digital angles with applied heel elevation.ResultsSGI values for SDFTs and DDFTs differed significantly in loaded versus unloaded tendons and at different locations of the metacarpus. Incremental heel elevation had the greatest and most consistent effect on the SGI in the mid-metacarpal region in both flexor tendons. At this level, the stiffness gradient tended to decrease when the angle of heel elevation increased from 0 to 8 degrees for both flexor tendons. There was a significant difference in SGI between loading and unloading the limb during AEG acquisition, with reduced variability when the digital flexor tendons were loaded.Conclusions and clinical relevanceResults indicated that the SGI of digital flexor tendons was significantly affected by heel elevation. Regarding technique, AEG can be easily and effectively utilized to measure flexor tendon strain in a standing horse with applied heel elevation. This model resulted in direct quantification of tendon strain as it relates to distal limb conformation, which would allow for more targeted therapeutic farriery techniques.