Digital Amputation Research Articles

Time to Amputation After Traumatic Digital Injury Does Not Affect Complication Rates: A Retrospective Multi-Institutional Analysis.

Revisionary digital amputations are often performed after partial or full traumatic digital amputation to minimize complications while preserving as much length and functionality as possible. Many surgeons attempt revisionary procedures swiftly after initial injury. The aim of this study was to investigate the effects of time from injury to surgery on rate of complications and reoperation in revisionary traumatic digital amputations. This was a retrospective chart review of all patients undergoing revisionary digital amputation for initial traumatic amputation at a single hospital from January 1, 2007 to December 31, 2021. Demographics, comorbidities, surgical details, complications, and time from injury to surgery were collected. Five-factor modified fragility index scores were also computed for each patient. Primary outcomes of interest included complications and need for additional procedures. Secondary outcomes of interest included development of neuroma, phantom limb, and referral to a long-term pain specialist. A total of 97 patients were identified as meeting all inclusion criteria. The average time to surgery was 14.4 days. Body mass index, comorbidities, and time to surgery were not associated with increased risk of complication. Increasing time to surgery was not significantly associated with increased risk of complications, development of neuroma, phantom limb, or a referral to long-term pain service. The only factors which were significantly associated with reoperation were absence of diabetes and hypertension. Increasing time to surgery after initial injury was not significantly associated with increased risk of complications or reoperation. Surgeons should consider this when assessing urgency of surgery in patients after traumatic digital amputation.

Epidemiological Analysis of Upper Extremity Amputations From Lawn Mower-Related Injuries.

Lawn mower-related injuries (LMIs) represent a complex spectrum of pathology with significant public health ramifications. The purpose of this study was to analyze the epidemiological factors associated with lawn mower upper extremity amputations. The National Electronic Injury Surveillance System (NEISS) database was queried from 2014 to 2023. National case estimates were established for upper extremity amputation events secondary to lawn mowers using diagnostic and injury-specific coding parameters. Documented cases from NEISS-participating hospitals were evaluated and injury data surrounding individual amputation events were analyzed. An estimated 17 509 upper extremity amputations occurred from 2014 to 2023 secondary to LMI in the United States. Annual case estimates and incidence rates remained relatively uniform across the 10-year study period. Most injuries were estimated to occur in 50- to 59-year-old patients. Case record review from pooled participating NEISS hospitals yielded 469 cases of upper extremity amputation directly associated with LMI from 2014 to 2023. Ninety-one percent of cases occurred in men, and most events involved the amputation of a finger (97%). Most cases of lawn mower-associated injury involved the amputation of the middle digit (41.6%) in isolation (64% of cases involved amputation of 1 digit). Despite advances in product safety and consumer education, the estimated frequency and incidence rate of upper extremity amputations secondary to LMI has remained largely unchanged over the past 10 years. When these events did occur, 40- to 60-year-old men were most often involved, most commonly leading to amputation of the third finger in isolation.

Abstract 4138717: Infective Root Aortitis: Medical Therapy Alone or Medical Therapy and Surgery?

Clinical presentation: A 75-year-old male with previous 3 vessel CABG and bioprosthetic aortic valve (BAV) surgical replacement in 2013 was admitted with severe sepsis from diabetic foot ulcer complicated with Group A Streptococcus bacteremia and infective root aortitis. Imaging Findings: Initial technically limited transthoracic echocardiogram was followed by a transesophageal echocardiogram (TEE) that demonstrated a well seated BAV with mildly thickened leaflets but no vegetations, mild intra-valvular regurgitation, and 9 mm end-diastolic soft tissue echoreflectant thickening of the posterior aortic root (AoR) extending up 3 cm from the aortic annulus to the ascending aorta (Fig 1A,B). There were no signs of perivalvular abscess formation. Initial FDG PET-CT demonstrated heterogenous hypermetabolic activity at the annulus of the BAV (Fig 1C) and AoR (Fig 1D) consistent with aortitis. Decision-making: In the absence of guidelines for the management of these patients, a multidisciplinary team including cardiology, cardiothoracic surgery, and infectious disease opted for a conservative medical therapy instead of high-risk surgery. Patient then underwent left foot first digit amputation to achieve infectious source control. Upon completion of 4 out of 6 weeks of intravenous ceftriaxone 2 grams daily, repeat TEE showed improved AoR thickening to 6 mm (Fig 1E,F), no AoR abscess, and unchanged BAV structure and function. Repeat FDG PET-CT at the same time of TEE demonstrated persistent but improved hypermetabolic activity of the BAV annulus and AoR. After 10 weeks of IV antibiotics, repeat FDG PET-CT showed further decrease in metabolic activity on both areas. However, an Indium-111 labeled leukocyte scan showed no activity at the BAV annulus and root (Fig 1G) and therefore indicated healed AoR aortitis, which was further supported by significant decrease of ESR and CRP initial values of 126 mm/hr and 122.7 mg/L to 11 mm/hr and 3 mg/L, respectively. Patient is currently clinically stable 8 months later. Conclusion: This case illustrates that a conservative management of infective AoR aortitis with an extended course of intravenous antibiotics is a reasonable alternative to high-risk re-do valve and root surgery.

Comparison of Hand Function after Single-Digit Replantation in Elderly and Younger Patients.

Background: With ageing of the population, there is an increasing likelihood that elderly people will seek employment, with a resultant increase in the incidence of hand injuries, including digital amputations. However, the surgical indication for replantation of an amputated digit in elderly patients is controversial. The purpose of this study was to compare functional outcomes after single-digit replantation of the thumb to long finger in older (≥65 years old) and younger (<65 years old) patients to assess the feasibility of digit replantation in the elderly population. Methods: A retrospective cohort study was performed in 25 patients (12 elderly and 13 younger) with successful replantation of the thumb, index or long finger at our hospital. All patients were followed up for more than 1 year. Key pinch strength, Semmes-Weinstein (S-W) test, % total active motion (TAM), Purdue Pegboard Test score (hand dexterity) and Disabilities of the Arm, Shoulder and Hand (DASH) score were investigated. Results: Elderly patients showed significantly worse results for the S-W test and Purdue Pegboard Test score. The % TAM, key-pinch strength and DASH scores were similar in the two groups. Conclusions: Replantation surgery in elderly patients results in similar postoperative hand function (finger mobility and pinch strength) and activities of daily living to those in younger patients. Level of Evidence: Level III (Therapeutic).

Targeted Muscle Reinnervation in the Hand for the Prevention and Treatment of Symptomatic Neuroma Following digit and Hand Amputations, A Prospective Case Series

Abstract Background Neuromas are a common complication after digital and hand amputations, resulting in significant pain, discomfort, and functional impairment. Various management methods are available, including surgical excision, nerve blocks, and nerve stump protectors, but these treatments may have limited success rates and potential complications. Targeted muscle reinnervation (TMR) is a promising technique that involves surgically rerouting a severed nerve into a nearby muscle, which can prevent the formation of neuromas and provide improved muscle function. Aim of the Work The aim of this work is to assess the efficacy of Targeted muscle reinnervation in the treatment and prevention of symptomatic neuromas in digit and hand amputations, to evaluate the surgical technique and to record any possible postoperative complications or improvements of the technique in the hand. Materials and Methods We conducted a prospective case series at Ain Shams University hospitals, we recruited 20 patients eligible for our study by our criteria with digit or hand amputation distal to the wrist crease or a symptomatic neuroma within the hand or digits starting from August 2021 and for 24 months. We excluded patients with cognitive impairment for better outcomes assessment and patients below 18 years old. Either 1ry or 2ry TMR was performed on each patient. Results It has resulted in remarkable improvement in the neuroma pain experienced by our hand trauma patients and showed a promise as both a therapeutic and preventative tool to reduce the formation of symptomatic neuromas. Conclusion The technique requires good knowledge of hand microsurgical anatomy and good training in microsurgery, we observed a decrease in the operative time towards the conclusion of the study which proves the learning curve. TMR has minimal morbidity and is easily reproducible as demonstrated by multiple surgeons performing the surgery with consistent results.

Finger Replantation: Indications and Outcomes

Very few cases cause such a visceral reaction in the hand or microsurgeon as a replantation. Since the first successful digital replantation in 1965, we have had nearly 60 years to reflect and learn from our experiences. Arguably, the most critical things we have come to understand are the indications, contraindications, and expected outcomes in this patient population. Specific indications are deemed absolute in nature. In almost all cases, the amputation of a thumb, the amputation of multiple digits, and an amputation in a child are all microsurgical emergencies that should proceed with an attempt at replantation. Relatively indicated injuries are those occurring in zone I and those based on patient wishes, which are often based on cultural or religious beliefs. Relative contraindications include zone II injuries (single digit), patient co-morbidities such as peripheral vascular disease or diabetes, smoking, and socioeconomic factors. Absolute contraindications typically revolve around the condition of the amputated part, the donor site, and the medical status of the patient. Should the procedure pose a threat to the patient’s survival, replantation should not proceed. Certain factors predict success, such as the type of injury and optimal surgical and post-surgical management. That said, success defined as digital viability is not the same as success defined as a functional digit. The results of replantation, though thought to be better than revision amputation, are certainly not as good as they can be. As we refine our indications and techniques, we can continue to improve outcomes in the future.

Hospital Transfers for Digit Replants as Cost Saving and Safe While Access to Replantation Procedures Remains Limited.

Finger replantation outcomes are influenced both by injury characteristics and by hospital and patient factors, such as hospital type/location and patient gender or insurance. Finger replantation success rates have been shown to be higher at hospitals with higher volumes of finger replants. This study examines the hospital and patient factors that influence hospital transfer and successful replantation in patients experiencing traumatic finger amputation. A total of 5219 patients were identified in the 2008-2015 National Inpatient Sample (NIS) as having experienced traumatic finger amputation with attempted replantation. Hospital transfer and replant outcomes were compared with variables such as patient demographics and hospital characteristics using χ 2 tests, t tests, ANOVA, and logistic regression. Traumatic digit amputation patients were most likely to be transferred to medium or large hospitals in urban areas. Hospital transfer was 1.5 times more likely in White patients than Black or Hispanic patients and 1.6 times more likely in middle income quartile patients than the top income quartile. Postreplant amputation was more likely in patients in the lower three income quartiles, on Medicare, of older age, or with more chronic conditions. Hospital transfer was not associated with changes in the probability of requiring amputation after replantation but was associated with a decreased cost of $5000. Hospital transfers for finger replants are safe with respect to replant failure rates and cost-effective, saving $5000 per procedure. Gaps in equitable access to care remain, warranting further study to improve health equity.

Multiple Free Flaps and Second Toe Transfer to Salvage Grasp Function in Bilateral Complete Degloved Hands

AbstractA 21-year-old male laborer sustained bilateral degloving injury of the hands with multiple digital amputations and devascularized digits. After X-rays, preliminary debridement was done, when digital amputations were completed, including index ray amputation on both sides. The next day, two anterolateral thigh (ALT) flaps and one second toe transfer were done to restore coverage in the palm and the web and reconstruct the lost thumb. This ensured both coverage and thumb length on the right side, but on the left side the procedure was terminated with flap transfer only. After 3 months, the other second toe was harvested with a dorsalis pedis flap for reconstruction of the left thumb, and a free gracilis flap was done for optimal donor site coverage in the donor left foot. Evaluation after 2 years showed functional hands with reasonable power grasp, pinch grip, and dexterity to manipulate small and large objects that permitted an independent living.

“Callus Bending Technique” Following Gradual Bone Lengthening for Functional Reconstruction in Cases of Phalangeal Loss Due to Digital Amputation: Two Case Reports

“Callus Bending Technique” Following Gradual Bone Lengthening for Functional Reconstruction in Cases of Phalangeal Loss Due to Digital Amputation: Two Case Reports

Examining characteristics of those who receive pedorthic services: A clinical audit.

Diabetes-related foot complications, including neuropathic plantar forefoot ulcers, are a significant contributor to morbidity and increased healthcare costs. This retrospective clinical audit examines the characteristics of people accessing pedorthics services who are at risk of neuropathic plantar forefoot ulcer (re)occurrence and the pathways and funding models used to access these services. A clinical record audit was conducted on all patients accessing a pedorthics service who had diabetes and neuropathy with a history of plantar forefoot ulceration. The data included demographics, diabetes and neuropathy duration, main forefoot pathology and other comorbidity, footwear and insole interventions, and health fund access status. A total of 70 patient records were accessed, and relevant data was extracted. The mean age of participants was 64.69 (standard deviation (SD) 11.78) years; 61% were male and 39% female. Duration of diabetes ranged from one to 35 years, with a mean of 14.09 years (SD 6.58). The mean duration of neuropathy was 8.56 (SD 4.16) years. The most common forefoot conditions were bony prominences at 71% (n = 50), rigid flat foot and limited joint mobility (53%, n = 37), and hallux abductovalgus at 47% (n = 33). All participants had hyperkeratosis; 34% (n = 24) had forefoot amputation, and around 34% (n = 24) had a history of digital amputation. Various publicly funded packages and private health insurance were accessed. This study investigates the sociodemographic and medical profiles of individuals with diabetes-related foot complexities prone to neuropathic plantar forefoot ulcers. It is the first to examine patients receiving pedorthic services, informing practitioner surveys and preventive care strategies. Understanding patient characteristics aids in optimising multidisciplinary care and reducing ulcer incidence. Further studies are warranted to explore the field to establish an effective multidisciplinary care approach between medical professionals, podiatrists and pedorthists to optimise patient outcomes.

Mycetoma affecting hand fingers: 3 Case reports

Digital locations of hand mycetoma are rare. They are most often described within the broader context of hand mycetoma. Herein, we report three cases of digital mycetoma.Case 1: A 33-year-old patient presenting with a mycetoma of the middle finger evolving for 5 years with osteitis of P1. A trans-P2 amputation was performed.Case 2: A 57-year-old patient presenting with a mycetoma of the little finger evolving for 12 years without bone involvement. Management consisted of excision surgery.Case 3: A 27-year-old patient presenting with a mycetoma of the ring finger evolving for 7 years with osteitis of P1 and fistula. Extension to the base of the little finger was noted. Digital amputation was refused by the patient.

Safe and genotyped. A non-invasive method for extraction of amphibian DNA from water baths and its application on Northern spectacled salamanders, Salamandrina perspicillata (Savi 1821)

The global decline of amphibian populations, with 40.7% of species classified as threatened, calls for innovative and ethical approaches in conservation genetics. Molecular biology advancements have introduced environmental DNA (eDNA) analysis, primarily focusing on aquatic environments. However, the present study explores a novel non-invasive protocol using water samples to extract DNA from terrestrial and semi-terrestrial amphibians, specifically the endangered Italian endemic salamander, Salamandrina perspicillata (Savi, 1821). Unlike traditional invasive methods involving tissue sampling, this protocol immerses animals briefly, eliminating the need for digit or tail amputations or manipulation for buccal swabs. The study validated the protocol through DNA extraction, amplification, and sequencing, yielding results comparable to traditional methods. The non-invasive nature of the protocol aligns with the 3Rs principles (Replace, Reduce, Refine) and offers a streamlined, stress-minimizing alternative for studying protected and endangered species. Future experiments should also explore further refinements, including reduced soaking times and additional applications, such as skin microbiota analysis. This protocol represents a significant step towards ethical and effective research practices in amphibian conservation genetics, encouraging a paradigm shift in wildlife research ethics. Continued innovation in non-invasive methodologies is essential for comprehensive understanding and robust conservation strategies amid the ongoing biodiversity crisis.

Predictors of leech therapy failure in revascularized and replanted digits

IntroductionVenous congestion is a common phenomenon following digital revascularization and replantation. Leech therapy allows for venous outflow while angiogenesis and neovascularization take place. The aim of this study is to evaluate the efficacy of leech therapy in the revascularized and replanted digits and determine risk factors for unsuccessful salvage. Materials and methodsA retrospective review was performed to identify all patients with complete or incomplete digital amputations at an academic Level 1 Trauma Center who underwent digital replantation or revascularization from January 2005 to December 2020. Amputations proximal to the palmar arch as well as revascularizations that showed any degree of perfusion on preoperative assessment were excluded. Leech therapy was initiated as soon as any signs of venous congestion appeared and was titrated to clinical effect. Patient demographics, medical history, injury mechanism, extent and level, operative details, leech therapy details, number of blood transfusions, hospitalization length, as well as the digit's ultimate survival data were collected. ResultsOf the 159 patients who underwent 213 digital revascularizations (n ​= ​135) and replantations (n ​= ​78), venous congestion requiring leech therapy developed in 27 digits in the revascularization group and in 26 in the replantation group. Of the digits that were leeched, 15 failed in the revascularization group (56 ​% failure rate) and 17 failed in the replantation group (65 ​% failure rate). Avulsion mechanism of injury and presence of a circumferential laceration were significantly associated with rate of failure in the revascularization cohort (p ​< ​0.01). Proximal level of injury was significantly associated with rate of failure in the replantation group (p ​< ​0.01). ConclusionLeech therapy has limited efficacy in avulsed or more proximally injured digits. These data can aid in determining the prognosis of a digit with venous congestion after revascularization and replantation.

Development and external validation of a prediction model for digit replantation failure after traumatic amputations based on a prospective multicenter cohort.

Failure of digit replantation after traumatic amputation is difficult to predict. The authors aimed to develop a prognostic model to better identify factors that better predict replantation failure following traumatic digit amputation. In this multicenter prospective cohort, the authors identified patients who had received digit replantation between 1 January 2015 and 1 January 2019. Univariable and multivariable analyses were performed successively to identify independently predictive factors for failure of replanted digit. To reduce overfitting, the Bayesian information criterion was used to reduce variables in the original model. Nomograms were created with the reduced model after model selection. This model was then internally validated with bootstrap resampling and further externally validated in validation cohort. Digit replantation was failed in 101 of 1062 (9.5%) digits and 146 of 1156 digits (12.6%) in the training and validation cohorts, respectively. The authors found that six independent prognostic variables were associated with digit replantation failure: age, mechanism of injury, ischemia duration, smoking status, amputation pattern (complete or incomplete), and surgeon's experience. The prediction model achieved good discrimination, with concordance indexes of 0.81 (95% CI: 0.76-0.85) and 0.70 (95% CI: 0.65-0.74) in predicting digit failure in the training and validation cohorts, respectively. Calibration curves were well-fitted for both training and validation cohorts. The proposed prediction model effectively predicted the failure rate of digit replantation for individual digits of all patients. It could assist in selecting the most suitable surgical plan for the patient.

Rate and Location of Reulceration and Reamputation After Partial First-Ray Amputation versus Hallux Amputation in Diabetic and Nondiabetic Populations.

We sought to determine the rates of reulceration and reamputation in individuals who underwent partial first-ray amputations versus hallux amputations in diabetic and nondiabetic populations. Eighty-four amputations were reviewed in a retrospective fashion. A retrospective medical record review was performed to determine patients who underwent a hallux amputation, both partial and complete, and patients who underwent a partial first-ray amputation. Only patients from 2007 to 2019 were reviewed. The reulceration rate of hallux amputations was 61% compared with a partial first-ray amputation reulceration rate of 74%. The reamputation rate of hallux amputation versus partial first-ray amputation was 43% versus 51%. At final follow-up, it was statistically significant that patients who underwent hallux amputation were more likely to be healed than those who underwent partial first-ray amputation, regardless of reulceration or reamputation. In addition, patients who underwent hallux amputation went on to digital amputation, and those who underwent partial first-ray amputation went on to transmetatarsal amputation. Comparing partial first-ray amputation to hallux amputation, hallux amputation patients are more prone to subsequent digital ulceration. Patients who initially undergo hallux amputation have variable subsequent amputations, often digital. Reulceration primarily occurs at the incision site for partial first-ray amputations, with a higher likelihood of subsequent transmetatarsal amputation. Patients with a medical history of diabetes and staged procedures are more likely to receive partial first-ray amputations. However, hallux amputation patients have a lower risk of reulceration and reamputation, regardless of subsequent events. These findings underscore the importance of discussing risks and preventive measures with patients undergoing such amputations, emphasizing postoperative examinations for specific areas of concern. Hallux amputation appears to offer greater protection against reulceration and reamputation for both diabetic and nondiabetic populations.

Pediatric Digit Replantation: A Nationwide Analysis of Failure Rate, Complications, and Potential Factors Affecting Failure

Function and cosmesis may be improved by replantation following digital amputation in pediatric patients. However, accurate failure and complication rate estimates may be limited as most pertinent studies reflect single center/surgeon experience and therefore are limited by small sample sizes. The primary aim of this study was to assess the rate of failure (amputation) following pediatric digital replantation. Secondary aims include evaluating the rate of complications and associated resource utilization (intensive care unit stays, readmission rate, and hospital length of stay). Digital replantation patients were identified from 47 pediatric hospitals using the 2004 to 2020 Pediatric Health Information System nationwide database. Using applicable International Classification of Disease 9/10 and Current Procedural Terminology codes, we identified complications after replantation, including revision amputation, infection, surgical complications, medical complications, admission to intensive care unit (ICU), and length of stay. Of the 348 patients who underwent replantation the mean age was 8.3 ± 5.1 years, and 27% were female. Mean hospital length of stay was 5.8 ± 4.7 (range, 1-28) days. Of the 53% of patients who required ICU admission, the mean ICU length of stay was 2.4 ± 3.3 days. Failure/amputation after replantation occurred in 71 (20.4%) patients, at a mean of 9.7 ± 27.2 days postoperatively. Surgical complications occurred in 58 (17%) patients, 30-day hospital readmissions occurred in 5.7% of patients, and 90-day readmissions occurred in 6.3% patients. The estimated rate of failure following pediatric digit replantation was 20%. Our data on failure and complication rates and associated resource utilization may be useful in counseling pediatric replantation patients and their families and provide an update on prior literature. IV, Prognosis.

REPLANTATION OF THE THUMB OR REVISION OF AMPUTATION: AN EPIDEMIOLOGICAL STUDY.

This article presents a retrospective cohort study analyzing patients from IOT-FMUSP who underwent replantation or revision amputation procedures for traumatic thumb amputation between 2013 and 2020. The study included 40 patients in the replanted group and 41 patients in the amputed group. The patients were divided according to the level of amputation and their medical records were analyzed. A total of 81 patients with digital amputation were analyzed, consisting of 79 males and 2 females, with mean ages of 43 and 49 for the amputed and replanted groups, respectively. According to the Biemer classification, 28.4% had proximal amputation, while 71.6% had distal amputation. The most common occupation was bricklayer (19.75%), and 80.24% were manual workers. Of the patients, 65% returned to their previous work, with 77.77% of them having amputation on their non-dominant hand, mostly caused by circular saw accidents (77.77%). The replantation success rate was 78%, with an average ischemia time of 9 hours and door-to-room time of 2 hours. the study findings revealed that traumatic thumb amputation predominantly affects working-age males with a low education level and the success rate of replantation was high in this ischemia time and door-to-room conditions. Level of Evidence II, Retrospective study.

A Prospective Study of Graft Repositioning over Flap Technique for Reconstruction of Fingertip Amputation.

Background: Replantation of digital tip amputations, especially Allen III and IV, is challenging for hand surgeons as it requires a high level of microsurgical expertise and fine instruments. The graft repositioning over flap (GRF) technique is a simple and reliable procedure that provides length, sensation and nail growth and GRF has become popular in the last few years. The aim of this study is to report the short-term outcomes of the GRF technique. Methods: This is a prospective study of all patients who underwent a GRF reconstruction for Allen III and IV digital amputations at our hospital over a 12-month period. In addition to demographic data and injury details, we collected outcomes data with regard to flap and nailbed graft survival, capillary refill time, nail growth, sensation (2-point discrimination), bone union and gain in length of digit compared to length at injury. Results: Twenty patients underwent GRF reconstruction of digital amputation. They included 18 men and 2 women with an average age of 29 years. The thumb was the most frequently injured digit (n=7). Electric saws (n=5) and industrial machines (n=5) accounted for 50% of injuries. Twelve amputations were Allen IV. Five patients were lost to follow-up and outcomes data was available for 15 patients. There was loss of flap and nail bed in three patients. There was no growth of nail in three patients. The distal phalanx graft was lost in six patients and united in the remaining nine patients. Conclusions: The GRF technique is a simple and reliable option in patients in whom replantation is not possible. It restores length, provides sensation and nail growth in the reconstructed fingers. Level of Evidence: Level IV (Therapeutic).

Induced regeneration of articular cartilage: Identification of a dormant regeneration program for a non-regenerative tissue.

An organoid culture model was developed to regenerate articular cartilage by sequential treatment with BMP2 and BMP9 that parallels induced joint regeneration at digit amputation wounds in vivo. BMP9 induced chondrogenesis was used to identify clonal cell lines of articular chondrocyte and hypertrophic chondrocyte progenitor cells from digit fibroblasts. A protocol that includes cell aggregation enhanced by BMP2 followed by BMP9 induced chondrogenesis resulted in the differentiation of organized layers of articular chondrocytes similar to the organization of middle and deep zones of articular cartilage in situ and retained a differentiated phenotype following transplantation. In addition, the differentiation of a non-chondrogenic connective tissue layer containing articular chondrocyte progenitor cells demonstrates that progenitor cell sequestration is coupled with articular cartilage differentiation at a clonal level. The studies identify a dormant endogenous regenerative program for a non-regenerative tissue in which fibroblast-derived progenitor cells can be induced to initiate morphogenetic and differentiative programs that include progenitor cell sequestration. The identification of dormant regenerative programs in non-regenerative tissues such as articular cartilage represents a novel strategy that integrates regeneration biology with regenerative medicine.

Solitary acrometastasis of the phalanx as initial presentation of an oligometastatic Kirsten rat sarcoma viral oncogene homolog-mutated lung adenocarcinoma: a case report

BackgroundAcrometastasis is an uncommon finding in non-small cell lung cancer and is usually a sign of multimetastatic disease. Few case reports have suggested solitary digital metastasis as the single secondary lesion of oligometastatic non-small cell lung cancer.Case presentationThis case report describes an unusual presentation of a Kirsten rat sarcoma viral oncogene homolog-mutated lung adenocarcinoma with a solitary bone metastasis in the fourth finger medial phalanx, which was also the first sign of the disease, in a 63-year-old Caucasian female patient. Digital surgical amputation was performed. After histopathological confirmation and radiological exclusion of other secondary lesions, chemoimmunotherapy in a first-line setting was initiated. A partial metabolic response in the primary lung lesion was observed after four cycles. Maintenance therapy is currently being continued.ConclusionSolitary digital metastasis is a rare finding in non-small cell lung cancer. Further studies are needed to investigate the mechanisms behind this particular dissemination process.