Addressing data imbalance in Sim2Real: ImbalSim2Real scheme and its application in finger joint stiffness self-sensing for soft robot-assisted rehabilitation.

The simulation-to-reality (sim2real) problem is a common issue when deploying simulation-trained models to real-world scenarios, especially given the extremely high imbalance between simulation and real-world data (scarce real-world data). Although the cycle-consistent generative adversarial network (CycleGAN) has demonstrated promise in addressing some sim2real issues, it encounters limitations in situations of data imbalance due to the lower capacity of the discriminator and the indeterminacy of learned sim2real mapping. To overcome such problems, we proposed the imbalanced Sim2Real scheme (ImbalSim2Real). Differing from CycleGAN, the ImbalSim2Real scheme segments the dataset into paired and unpaired data for two-fold training. The unpaired data incorporated discriminator-enhanced samples to further squash the solution space of the discriminator, for enhancing the discriminator's ability. For paired data, a term targeted regression loss was integrated to ensure specific and quantitative mapping and further minimize the solution space of the generator. The ImbalSim2Real scheme was validated through numerical experiments, demonstrating its superiority over conventional sim2real methods. In addition, as an application of the proposed ImbalSim2Real scheme, we designed a finger joint stiffness self-sensing framework, where the validation loss for estimating real-world finger joint stiffness was reduced by roughly 41% compared to the supervised learning method that was trained with scarce real-world data and by 56% relative to the CycleGAN trained with the imbalanced dataset. Our proposed scheme and framework have potential applicability to bio-signal estimation when facing an imbalanced sim2real problem.

Evaluation of the Rennes Universal Measurement Method (RUMM), an artificial intelligence application for hand joint angle assessment.

Although goniometric measurement is considered the gold standard for the measurement of digital range of motion, visual estimation is often employed due to its simplicity despite being inconsistent with recommended guidelines. We evaluated the Rennes Universal Measurement Method, an innovative tool employing artificial intelligence to concurrently analyse hand joint angles based on a single photograph. We found a strong correlation between the goniometric method and the photograph-based approach (Spearman correlation coefficient 0.7). The mean standard error of measurement was -1° (SD 17°). Regarding reproducibility with different photographic angles, an excellent intraclass correlation coefficient of 0.9 was noted. The tool had a processing time of less than 0.1 s per hand, while traditional goniometric methods took 20-30 s per finger. Combining simplicity, high reproducibility and good inter-rater reliability, this is a potentially useful tool that can be used to monitor patient progress in place of traditional goniometry.

Subtle Radiographic Progression at Six Months Can Be Detected Using Automated Quantitative Software in Rheumatoid Arthritis While Receiving Tocilizumab.

OBJECTIVES: We investigated whether our in-house software equipped with partial image phase-only correlation (PIPOC) can detect subtle radiographic joint space narrowing (JSN) progression at six months and predict JSN progression in rheumatoid arthritis (RA) patients receiving Tocilizumab. METHODS: The study included 39 RA patients who were treated with Tocilizumab. Radiological progression of the metacarpophalangeal and the proximal interphalangeal joints was evaluated according to the Genant-modified Sharp score (GSS) at 0, 6, and 12 months. Automatic measurements were performed with the software. We validated the software in terms of accuracy in detecting the JSN progression. RESULTS: The success rate of the software for joint space width (JSW) measurement was 96.8% (449/464). The 0-12-month JSW change by the software was significantly greater in joints with the 0-6-month PIPOC (+) group than the 0-6-month PIPOC (-) group (p < 0.001). The 0-12-month JSW change by the software was 0-12-month GSS (+) than with 0-12-month GSS (-) (p = 0.02). Here, "(+)" indicates the JSN progression during the follow-up period. Meanwhile, "(-)" indicates no JSN progression during the follow-up period. Linear regression tests showed significant correlations between the 0-6-month and the 0-12-month PIPOC in the left 2nd and 3rd MCP joints (R2 = 0.554 and 0.420, respectively). CONCLUSIONS: Our in-house software equipped with PIPOC could predict subsequent JSN progression with only short-term observations.

A rotary transformer cross-subject model for continuous estimation of finger joints kinematics and a transfer learning approach for new subjects.

Introduction: Surface Electromyographic (sEMG) signals are widely utilized for estimating finger kinematics continuously in human-machine interfaces (HMI), and deep learning approaches are crucial in constructing the models. At present, most models are extracted on specific subjects and do not have cross-subject generalizability. Considering the erratic nature of sEMG signals, a model trained on a specific subject cannot be directly applied to other subjects. Therefore, in this study, we proposed a cross-subject model based on the Rotary Transformer (RoFormer) to extract features of multiple subjects for continuous estimation kinematics and extend it to new subjects by adversarial transfer learning (ATL) approach. Methods: We utilized the new subject's training data and an ATL approach to calibrate the cross-subject model. To improve the performance of the classic transformer network, we compare the impact of different position embeddings on model performance, including learnable absolute position embedding, Sinusoidal absolute position embedding, and Rotary Position Embedding (RoPE), and eventually selected RoPE. We conducted experiments on 10 randomly selected subjects from the NinaproDB2 dataset, using Pearson correlation coefficient (CC), normalized root mean square error (NRMSE), and coefficient of determination (R2) as performance metrics. Results: The proposed model was compared with four other models including LSTM, TCN, Transformer, and CNN-Attention. The results demonstrated that both in cross-subject and subject-specific cases the performance of RoFormer was significantly better than the other four models. Additionally, the ATL approach improves the generalization performance of the cross-subject model better than the fine-tuning (FT) transfer learning approach. Discussion: The findings indicate that the proposed RoFormer-based method with an ATL approach has the potential for practical applications in robot hand control and other HMI settings. The model's superior performance suggests its suitability for continuous estimation of finger kinematics across different subjects, addressing the limitations of subject-specific models.

Reliability and clinical utility of a novel telehealth-based goniometry approach to measure range of motion of the digits of the hand.

BACKGROUND: Range of motion (ROM) is an outcome measure commonly used when treating acute and chronic hand injuries and conditions. Increased adoption of telehealth service provision in hand therapy practice, influenced by the advent of COVID-19, has led to the need for a valid and reliable approach to measure the range of motion of the digits of the hand when providing hand therapy services using telehealth. PURPOSE: To determine if performing manual goniometry during a livestream teleconsultation is reliable and clinically useful to measure the range of motion of the fifth digit when providing hand therapy services using telehealth. STUDY DESIGN: Clinical measurement, repeated-measures study. METHODS: According to a measurement protocol, 12 independent raters (who currently provide hand therapy services) each obtained several screen-based goniometric range of motion measurements of the fifth digit at 2-time points. Raters were surveyed on the clinical utility of the telehealth-based goniometry approach. Measures of relative and absolute reliability were calculated to evaluate test-retest and inter-rater reliability. Free-text responses were analyzed using content analysis. RESULTS: Inter-rater reliability was excellent for all flexion and extension measures (intraclass correlation coefficient [ICC] ≥ 0.89) but poor for the arc of motion (ICC ≤ 0.67). Test-retest reliability was poor (ICC ≤ 0.43). No statistically significant differences between test and retest measurements were observed (P ≥ 0.24). The overall coefficient of variation indicated good precision (14.69%). Measurement error (≤6.07º) and limits of agreement (≤6.33) had acceptable levels to support clinical use. Content analysis revealed several practical considerations. CONCLUSIONS: This study suggests that performing manual goniometry during a livestream teleconsultation is unreliable for measuring the range of motion of the fifth digit. However, when combined with patient-reported and functional outcomes, this approach may be suitable to facilitate a range of motion assessment for certain functions of telehealth service provision in hand therapy practice.

Fixation of Mallet Fractures Using a Modified Hook Plate Technique: A Prospective Case Series of 17 Patients.

Objective Various modalities have been suggested to manage mallet fractures; however, inappropriate treatment can lead to extension lag, a swan neck deformity, or arthritis of the distal interphalangeal joint (DIPJ). The current study aimed to evaluate the results (functional, radiological, and complications) of open reduction and internal fixation (ORIF) of mallet fractures using low-cost hook plates fabricated from low-profile titanium mini plates. Methods A prospective case series of 17 consecutive patients (average age of 32.3 years) with mallet fractures (six were Wehbe Type IB and 11 were Wehbe Type IIB). Eleven (64.7%) were males. The affected hand was dominant in all patients, and the affected digit was the index in 6 (35.3%), the ring in 5 (29.4%), the small in 3 (17.65%), and the middle in 3 (17.65%) patients. The same fellowship-trained hand surgeon performed all surgeries. Results The average operative time was 37.65 minutes. After an average follow-up of 10.94 months (range 6-27), the average DIPJ motion was 50° ° (range 20°-70°), the extensor lag was noted in 4 (23.5%) patients, and complications were reported in 6 (35.29%) patients. According to Crawford criteria, 6 (35.3%) patients achieved excellent results, 7 (41.2%) achieved good results, and 4 (23.5%) achieved fair results. Conclusion The modified hook plate technique for fixation of mallet fractures is a beneficial, economical, yet demanding technique that adequately provides stable fixation to allow early DIPJ motion with acceptable functional outcomes.

Bimodal buckling governs human fingers' luxation.

Equilibrium bifurcation in natural systems can sometimes be explained as a route to stress shielding for preventing failure. Although compressive buckling has been known for a long time, its less-intuitive tensile counterpart was only recently discovered and yet never identified in living structures or organisms. Through the analysis of an unprecedented all-in-one paradigm of elastic instability, it is theoretically and experimentally shown that coexistence of two curvatures in human finger joints is the result of an optimal design by nature that exploits both compressive and tensile buckling for inducing luxation in case of traumas, so realizing a unique mechanism for protecting tissues and preventing more severe damage under extreme loads. Our findings might pave the way to conceive complex architectured and bio-inspired materials, as well as next generation artificial joint prostheses and robotic arms for bio-engineering and healthcare applications.

Does distal interphalangeal joint arthrodesis affect proximal interphalangeal joint arthroplasty outcomes in the same finger?

The purpose of this study was to analyse the 1-year outcomes after combining a surface replacing proximal interphalangeal joint arthroplasty and a distal interphalangeal screw arthrodesis and to compare the combined surgery with proximal interphalangeal joint arthroplasty alone. To obtain two groups with similar baseline data from our prospective registry, propensity score matching was used to match 23 fingers with the combined operations with 115 fingers with proximal interphalangeal joint arthroplasty alone. One year after surgery, the mean ranges of motion were 60° (95% CI: 53° to 67°) in the combined group and 63° (95% CI: 60° to 66°) in the control group and did not differ significantly. Grip strength, the brief Michigan Hand Questionnaire and pain also did not differ between the groups 1 year after surgery. All the proximal interphalangeal implants in patients treated with a distal interphalangeal screw arthrodesis remained in situ. Combining proximal interphalangeal joint arthroplasty with distal interphalangeal arthrodesis leads to 1-year outcomes that are similar to those achieved by proximal interphalangeal joint replacement alone.Level of evidence: III.

Effects of metacarpophalangeal joint position and finger joint movement speed on lumbrical muscle activity.

OBJECTIVES: The effect of metacarpophalangeal joint position and finger joint movement speed on lumbrical muscle activity remains unproven and was examined in this study. MATERIAL AND METHODS: Twenty-four healthy adults performed flexion-extension movements of the index finger in different metacarpophalangeal joint positions (extension or flexion) and movement speeds (60, 120, 240, and 360 beats per minute). The activities of the first lumbrical, first dorsal interosseous, and extensor digitorum muscles were evaluated using surface electromyography, and compared with those during finger joint extension. RESULTS: The metacarpophalangeal joint positions affected only lumbrical muscle activity, which was greater during extension. Further, finger movement speed affected the lumbrical and extensor digitorum muscle activities, which increased with increasing movement speeds. CONCLUSION: The present study suggests that position and movement speed can influence the lumbrical muscle activity during metacarpophalangeal joint extension. These findings may help expound lumbrical function and develop suitable strategies for inducing lumbrical muscle activity.

[Sports-related injuries of the thumb and fingers]. / Sportverletzungen des Daumens und der Finger.

Finger and thumb injuries are common in established and trend sports. Imaging plays an important role in acute trauma care, further therapy planning, and ultimately for a rapid return to play. Sound knowledge of the complex anatomy of the fingers and thumb is indispensable for accurate diagnosis. This article presents the ligament anatomy of the metacarpophalangeal and interphalangeal joints of the finger and the thumb, the extensor and flexor tendon apparatus, and the diagnosis of typical sports injuries using x­rays and magnetic resonance imaging. Furthermore, imaging findings of typical sports-associated injuries are illustrated.

Long-term preservation of metacarpophalangeal joint function in traumatic defects by metatarsophalangeal osteochondral transplantation.

INTRODUCTION: The integrity of the metacarpophalangeal (MCP) joints is essential for finger and hand function. Preservation of range-of-motion is one of the aims in reconstruction of complex injuries to these joints. Osteochondral transplants have shown to be reliable in reconstruction of various joint defects. This series presents three patients with traumatic injuries to four MCP joints, which were reconstructed by seven avascular osteochondral transplants of metatarsophalangeal (MTP) joints. The joints were examined for radiographic signs of resorption or joint space narrowing, and if this would affect the joints' function in the long term. METHODS: In three patients (40, 45 and 48 years) with complex injuries to their MCP joints (one milling, two saw injuries), four joints were reconstructed by three metatarsal head and four osteochondral transplants of the base of the proximal toe phalanges. Beside the joint itself, various soft tissue defects were reconstructed in each patient. The patients were clinically and radiographically examined after 9, 6, respectively, 7 years. RESULTS: All patients were satisfied with the result without any pain in the MCP joints. Range-of-motion in the four affected joints rated 25, 60, 75, and 80°, DASH scores rated 13, 29, and 17, respectively. None of the patients complained of problems at their feet. Radiographic examination revealed moderate joint space narrowing in one of the four joints. In another patient, localized osteolysis was found around the screws' heads, so that the screws were removed 7 years post-op. CONCLUSIONS: Osteochondral transplants for reconstruction of MCP defects are able to preserve function in severely injured joints even in the long term. Joint space narrowing may occur, which is not accompanied by pain, however. Since localized osteolysis can cause screw head prominence, mid-term radiographic follow-up is necessary to prevent damage to the joint. In the long term, remaining bone stock may be adequate for total joint replacement.

Fixation of Mallet Fractures Using a Modified Hook Plate Technique: A Prospective Case Series of 17 Patients / Fixação de fraturas em martelo com técnica de placa de gancho modificada: Uma série de casos prospectivos de 17 pacientes

Abstract Objective Various modalities have been suggested to manage mallet fractures; however, inappropriate treatment can lead to extension lag, a swan neck deformity, or arthritis of the distal interphalangeal joint (DIPJ). The current study aimed to evaluate the results (functional, radiological, and complications) of open reduction and internal fixation (ORIF) of mallet fractures using low-cost hook plates fabricated from low-profile titanium mini plates. Methods A prospective case series of 17 consecutive patients (average age of 32.3 years) with mallet fractures (six were Wehbe Type IB and 11 were Wehbe Type MB). Eleven (64.7%) were males. The affected hand was dominant in all patients, and the affected digit was the index in 6 (35.3%), the ring in 5 (29.4%), the small in 3 (17.65%), and the middle in 3 (17.65%) patients. The same fellowship-trained hand surgeon performed all surgeries. Results The average operative time was 37.65 minutes. After an average follow-up of 10.94 months (range 6-27), the average DIPJ motion was 50º º (range 20º-70º), the extensor lag was noted in 4 (23.5%) patients, and complications were reported in 6 (35.29%) patients. According to Crawford criteria, 6 (35.3%) patients achieved excellent results, 7 (41.2%) achieved good results, and 4 (23.5%) achieved fair results. Conclusion The modified hook plate technique for fixation of mallet fractures is a beneficiai, economical, yet demanding technique that adequately provides stable fixation to allow early DIPJ motion with acceptable functional outcomes.

Resumo Objetivo Diversas modalidades têm sido sugeridas para o tratamento de fraturas em martelo; no entanto, o tratamento inadequado pode causar retardo de extensão, deformidade em pescoço de cisne ou artrite da articulação interfalangiana distal (AIFD). Este estudo teve como objetivo avaliar os desfechos (funcionais, radiológicos e complicações) da redução aberta e fixação interna (RAFI) das fraturas em martelo com placas de gancho de baixo custo fabricadas com mini placas de titânio de baixo perfil. Métodos Série de casos prospectivos de 17 pacientes consecutivos (idade média de 32,3 anos) com fraturas em martelo (seis do tipo IB e 11 do tipo IIB de Wehbe). Onze (64,7%) pacientes eram do sexo masculino. A mão acometida era a dominante em todos os pacientes, com acometimento do dedo indicador em seis (35,3%), anelar em cinco (29,4%), mínimo em três (17,65%) e médio em três (17,65%) pacientes. O mesmo cirurgião de mão experiente realizou todas as cirurgias. Resultados O tempo operatório médio foi de 37,65 minutos. Após um acompanhamento médio de 10,94 meses (intervalo de 6 a 27), observou-se movimento médio da AIFD de 50º (intervalo de 20º a 70º), retardo de extensão em quatro (23,5%) pacientes e complicações em seis (35,29%) pacientes. De acordo com os critérios de Crawford, os desfechos foram excelentes em seis (35,3%), bons em sete (41,2%) e regulares em quatro (23,5%) pacientes. Conclusão A técnica da placa de gancho modificada para fixação de fraturas em martelo é benéfica e econômica, mas exigente; permite fixação estável e adequada para permitir a movimentação precoce da AIFD com desfechos funcionais aceitáveis.

Selected Mechanical Properties of Glue-Laminated Timber Produced from Locally Repaired Timber.

This study aimed to evaluate the mechanical properties determined in a 4-point bending test of beams made of lumber from which knots had been locally removed and the resulting loss replaced with sound wood. Three sets of beams were prepared, which differed in the number of layers/lamellas and the position of the lamellas from which edge knots were removed. All the lamellas used in the tests were subjected to a modulus of elasticity assessment. In addition to the distribution of defects, it determined the position of a given piece in the beam structure. The tests showed that high mechanical properties could characterise the beams produced in this way, i.e., a modulus of elasticity close to 12 kN/mm2 and a strength above 40 N/mm2, if the lamellas without knots were located below the outer tension lamella. Significantly better results were obtained when PUR glue was used in the inserts rather than MUF. In this case, beams with an improved outer lamella in the tension zone using semi-circular inserts glued with PUR glue had an average strength of 34.6 N/mm2.

Preoperative Thresholds of Pain and Function to Achieve a Minimal Important Change and Patient Acceptable Symptom State After Proximal Interphalangeal Joint Arthroplasty.

PURPOSE: There is ongoing discussion about the level of symptoms patients with proximal interphalangeal (PIP) joint osteoarthritis should have to undergo surgery. The aims of our study were to determine the minimal important change (MIC) and patient acceptable symptom state (PASS) for PIP joint range of motion (ROM), and define clinically relevant thresholds of preoperative pain and function at which patients have the greatest chance to achieve a MIC and PASS in these outcomes 1 year after PIP arthroplasty. METHODS: We analyzed registry data that included patients with PIP joint osteoarthritis who underwent an arthroplasty for this condition and had a 1-year follow-up. Patients indicated pain on a numeric rating scale (0-10) and completed the brief Michigan Hand Outcomes Questionnaire (MHQ). Active total PIP ROM was measured. The preoperative thresholds, predictive of achieving the MIC and PASS for each outcome measure of pain, function, and ROM, were determined using receiver operating characteristics curves. RESULTS: We included 196 patients who experienced a relevant improvement in ROM (= MIC) when there was an increase by ≥8° compared with the ROM preoperatively. Patients were satisfied with their postoperative ROM (= PASS) if they achieved PIP mobility of at least 66°. Pain at rest and during activities was predictive for achieving a MIC but not a PASS. Due to an insufficient area under the curve for the brief MHQ and ROM, their baseline values cannot predict the postoperative achievement of MIC or PASS. We suggest that patients with preoperative pain at rest ≥4.5 or pain during activities ≥5.5 have the greatest chance of achieving a subjectively relevant change 1 year after surgery. CONCLUSIONS: The determined thresholds may support surgeons in the preoperative process of deciding for or against a surgical intervention and explain the probability of achieving sufficient postoperative symptom relief for the patient. LEVEL OF EVIDENCE: Prognostic I.

The Inlay Technique with Cortico-Cancellous Olecranon Bone Graft Used for Revision of Failed Distal Interphalangeal Joint Arthrodesis.

Background and Objectives: Although distal interphalangeal (DIP) arthrodesis is an effective surgical method for end-stage osteoarthritis of the phalangeal joint, the nonunion rate of DIP arthrodesis has been reported to range from 15% to 20%. To this end, we devised an inlay technique with a cortico-cancellous olecranon bone graft for failed DIP arthrodesis. This study aimed to introduce the inlay bone grafting technique for failed arthrodesis of the DIP joint and demonstrate its advantages. Materials and Methods: We reviewed consecutive 19 digits (15 patients) who had undergone DIP revision arthrodesis using the technique at our institution between January 2010 and December 2020. The observed outcome measures were the bone union rate, and related complications. Bone union was evaluated using follow-up radiography. The quick Disabilities of the Arm, Shoulder and Hand (DASH), visual analog scale (VAS) for pain, and VAS for satisfaction assessed patient function and perceived clinical outcomes. Results: No major complications were observed at the recipient site. The average VAS for pain and satisfaction and DASH score improved from preoperatively to 6 months after surgery (both, p = 0.001). Conclusions: The inlay technique with cortico-cancellous olecranon bone grafts showed excellent bone union rates and functional scores with nonunion of the DIP joint. This technique may be an adequate surgical option for patients with confirmed nonunion of the DIP joint and persistent symptoms.

[Hand Osteoarthritis - Clinical Picture and Current Management]. / Fingerpolyarthrose ­ klinisches Bild und zeitgemässes Management.

Hand Osteoarthritis - Clinical Picture and Current Management Abstract. Finger joint osteoarthritis (HOA) is a common joint disease that increases with age. The cause is polyethiological. The distal joints of the fingers are most frequently affected, followed by the carpometacarpal joint of the thumb, the proximal interphalangeal joints, and the metacarpophalangeal joints. The clinical symptoms of HOA are painful functional restrictions of the hand and fingers. In terms of therapy, lifestyle modifications and exercise are primarily recommended. Only when these measures are inadequate or not helpful drugs will be recommended be recommended. First-choice drugs are non-steroidal anti-inflammatory drugs applied topically or p.o. Pharmaceutically manufactured chondroitin preparations are also helpful. In severely painful or erosive forms of HOA, corticosteroids can be used intra-articularly. The status of laser therapy or fractionated radiation is (still) unclear. Classical disease-modifying drugs such as those used in inflammatory joint diseases have no therapeutic value. Surgical interventions should be considered if conservative treatments are not sufficiently helpful and hand function is significantly impaired.

Classificação e tratamento da mão em fenda: revisão da literatura / Cleft hand classification and treatment: literature review

A mão em fenda é uma deformidade congênita rara caracterizada por uma deficiência longitudinal dos raios centrais da mão, podendo estar associada a outras malformações. Devido ao amplo espectro de manifestações, o tratamento de mãos em fenda é desafiador. Este estudo objetiva apresentar as classificações, técnicas cirúrgicas mais indicadas e seguimentos adotados conforme a manifestação clínica. Foi realizada uma pesquisa nos bancos de dados Web of Science, PubMed, Scopus, Cochrane e Embase, descritores e termos relacionados à anomalia mão em fenda típica. Trinta e dois artigos foram incluídos, sendo analisados quanto a classificação da anomalia, classificação da gravidade de expressão, técnicas cirúrgicas e estudos com informações da intervenção cirúrgica adotada para uma coorte de pacientes. Considerando que estudos sobre mão em fenda são diretamente afetados pelas descobertas embriológicas, genéticas e de biologia molecular, diferentes classificações foram descritas e diversos estudos de complementação de técnicas cirúrgicas já existentes foram encontrados. Estudos inovadores são escassos. A padronização na descrição das técnicas e resultados, além de pesquisas de melhor qualidade, poderiam elucidar lacunas ainda existentes em torno das opções de tratamento.

Cleft hand is a rare congenital deformity characterized by a longitudinal deficiency of the central rays of the hand, which may be associated with other malformations. Due to the wide spectrum of manifestations, the treatment is challenging. This study aims to present the most suitable classifications, surgical techniques and follow-up adopted according to the clinical manifestation. A search was performed in the databases Web of Science, PubMed, Scopus, Cochrane and Embase, descriptors and terms related to the hand anomaly in a typical cleft. Thirty-two articles were included and analyzed regarding the classification of the anomaly, classification of the severity of expression, surgical techniques and studies with information on the surgical intervention adopted for a cohort of patients. Considering that studies about cleft hand could be directly affected by embryological, genetic and molecular biology discoveries, different classifications have been described and several studies to complement existing surgical techniques have been found. Innovative studies are scarce. Standardization in the description of techniques and results, in addition to better quality research, could elucidate gaps that still exist around treatment options.

Distal interphalangeal joint arthrodesis with nonaxial multiple small screws: a biomechanical analysis with axial headless compression screw and clinical result of 15 consecutive cases.

BACKGROUND: The axial headless compression screw (AHCS) technique is a widely used method for distal interphalangeal joint (DIPJ) and thumb IPJ arthrodesis. However, it might not be suitable for cases over 10° flexion of fusion angle and extremely small-sized phalanx. Here, the authors describe the nonaxial multiple small screws (NMSS) technique, compare the mechanical strength of the NMSS technique with the AHCS technique, and suggest clinical outcomes of the NMSS technique. METHODS: DIPJ and thumb IPJ arthrodesis models were simulated in the 4th generation composite bone hand. Fixation with three 1.5 mm cortical screws (NMSS) or one HCS (AHCS) was performed in each pair of the phalanx. The bending stiffness and load to failure were tested in 10 pairs of each specimen, and the torsional stiffness and torque to failure were tested in seven pairs of each specimen. Moreover, 15 consecutive clinical DIPJ and thumb IPJ arthrodesis cases were reviewed retrospectively. RESULTS: The NMSS specimens showed significantly higher bending load to failure, torsional stiffness, and torque to failure than the AHCS specimens. All 15 arthrodesis cases were united without severe complications. The mean fusion angle was 16.3° for the nine cases of the flexed target position. CONCLUSIONS: The NMSS technique showed biomechanical stability comparable to that of the AHCS technique in DIPJ and thumb IPJ arthrodesis. Thus, the NMSS technique could be used as a feasible option in DIPJ and thumb IPJ arthrodesis, especially when a small finger is indicated and a significant flexion angle is required.

[Minimally invasive procedures in the early stages of trapeziometacarpal joint osteoarthritis : Denervation, arthroscopy and autologous fat transplantation]. / Minimal-invasive Verfahren im Frühstadium der Daumensattelgelenksarthrose : Denervierung, Arthroskopie, autologe Fetttransplantation.

BACKGROUND: Resection arthroplasty of the trapezium with or without tendon interposition is the standard procedure in the treatment of advanced, symptomatic thumb carpometacarpal joint osteoarthritis. Treatment recommendation in the early stages without visible or minimal radiographic changes is often difficult, especially when conservative treatment methods have already been exhausted. In these cases, there is the possibility of the minimally invasive methods of denervation, arthroscopic procedures and autologous fat transplantation. OBJECTIVES: Which minimally invasive procedures are available for the treatment of thumb carpometacarpal joint osteoarthritis and how is their value to be assessed? METHODS: The minimally invasive methods of denervation, arthroscopic procedures and autologous fat transplantation for the treatment of thumb carpometacarpal joint osteoarthritis are described and current results from the literature are discussed. RESULTS: Good results have been reported with all three procedures. However, the reports are almost exclusively based on retrospective studies with small numbers of patients, which lack control groups, so the results cannot be regarded as definitive. CONCLUSIONS: Denervation, arthroscopic procedures and autologous fat transplantation appear to be suitable methods in the early stages of thumb carpometacarpal joint osteoarthritis. Further studies, especially comparative randomised trials that report medium and long-term results, would allow further assessment of these methods.

Comparison of AI-powered 3D automated ultrasound tomography with standard handheld ultrasound for the visualization of the hands-clinical proof of concept.

OBJECTIVE: To assess the ability of a newly developed AI-powered ultrasound 3D hand scanner to visualize joint structures in healthy hands and detect degenerative changes in cadaveric hands. MATERIALS AND METHODS: Twelve individuals (6 males, 6 females, age 43.5 ± 17.8 years) underwent four scans with the 3D ultrasound tomograph (right and left hand, dorsal and palmar, respectively) as well as four sets of handheld ultrasound of predefined anatomic regions. The 3D ultrasound tomographic images and the standard handheld ultrasound images were assessed by two radiologists with regard to visibility of bone contour, joint capsule and space, and tendons. In addition, three cadaveric hands were scanned with the 3D ultrasound tomograph and CT. RESULTS: Mean scan time for both hands was significantly faster with handheld ultrasound (10 min 30 s ± 95 s) compared to 3D ultrasound tomography (32 min 9 s ± 6 s; p < 0.001). Interreader and intermodality agreement was moderate (0.4 < κ ≤ 0.6) to substantial (0.6 < κ ≤ 0.8). Overall visibility of joint structures was comparable between the modalities at the level of the wrist (p = 0.408), and significantly better with handheld ultrasound at the level of the finger joints and the thumb (both p < 0.001). The 3D ultrasound tomograph was able to detect osteophytes in cadaveric hands which were confirmed by CT. CONCLUSION: The AI-powered 3D ultrasound tomograph was able to visualize joint structures in healthy hands and singular osteophytes in cadaveric hands. Further technical improvements are necessary to shorten scan times and improve automated scanning of the finger joints and the thumb.