Grip and pinch strength prediction models based on hand anthropometric parameters: an analytic cross-sectional study.

BACKGROUND: Hand grip strength (HGS) and pinch strength are important clinical measures for assessing the hand and overall health. OBJECTIVE: The aim of the present study is to predict HGS and pinch strength based on 1 hand anthropometry, and (2) body anthropometric parameters using machine learning. METHODS: A Secondary analysis was conducted on 542 participant aged 30-60 years from the Persian Organizational Cohort study in Mashhad University of Medical Sciences. Artificial Neural Network (ANN) were fitted as prediction model. The dataset was divided into two sets: a training set, which comprised 70% of the data, and a test set, which comprised 30% of the data. Various combinations of the hand anthropometric, demographic, and body anthropometric parameters were used to determine the most accurate model. RESULTS: The optimal HGS model, using the input of gender, body mass, and hand anthropometric parameters of length (both total length and palm), maximum width, maximum breadth, and hand shape index, achieved nearly equal accuracy to the model that incorporated all variables (RMSE = 5.23, Adjusted R2 = 0.67). As for pinch strength, gender, hand length (both total length and palm), maximum width, maximum breadth, hand shape index, hand span, and middle finger length came closest to the model incorporating all variables (RMSE = 1.20, Adjusted R2 = 0.52). CONCLUSION: This ANN model showed that hand anthropometric parameters of total length, palm length, maximum width, maximum breadth, and the hand shape index, emerge as optimal predictors for both HGS and HPS. Body anthropometric factors (e.g., body mass) play roles as predictors for HGS, whereas their influence on pinch strength appears to be less pronounced. LEVEL OF EVIDENCE: Level III (Diagnosis). TRIAL REGISTRATION: Not applicable.

Pressure Sensors for Evaluating Hand Grasp and Pinch.

This study addresses the need for highly sensitive tools to evaluate hand strength, particularly grasp and pinch strength, which are vital for diagnosing and rehabilitating conditions affecting hand function. Current devices like the Jamar dynamometer and Martin Vigorimeter, although reliable, fail to measure extremely low force or pressure values required for individuals with severe hand impairments. This research introduces a novel device, a modified Martin Vigorimeter, utilizing an ultra-soft latex chamber and differential pressure measurement to detect minute pressure changes, thus significantly enhancing sensitivity. The device offers a cost-effective solution, making advanced hand strength evaluation more accessible for clinical and research applications. Future research should validate its accuracy across diverse populations and settings, exploring its broader implications for hand rehabilitation and occupational health.

Assessment and treatment of nonsurgical thumb carpometacarpal joint osteoarthritis: A modified Delphi-based consensus paper of the American Society of Hand Therapists.

BACKGROUND: While the literature is abundant on hand therapy assessment and treatment of nonsurgical thumb carpometacarpal (CMC) osteoarthritis (OA), clarity and uniformity are meager, making it a desirable diagnosis to establish expert consensus. PURPOSE: This study aimed to ascertain if consensus exists for the assessment and treatment of nonsurgical management of thumb CMC OA in the hand therapy clinical setting. STUDY DESIGN: This was a consensus paper via the modified Delphi approach. METHODS: A modified Delphi method was used to determine consensus among an expert panel, including hand therapists and hand surgeons, via two online surveys. A consensus paper steering committee (from the American Society of Hand Therapist's research division) designed the surveys and analyzed responses. Consensus was established as 75% agreement among the expert panel. Demographic information was collected from the expert panel. RESULTS: The expert panel included 34 hand therapists and seven hand surgeons. The survey response rates were 93.6% for the first survey and 90.2% for the second survey. Consensus recommendations were classified according to the World Health Organization categorization. These included evaluating the body structures for clinical signs/clinical testing and body functions for pain, range of motion for palmar abduction, radial abduction, opposition, and thumb metacarpal phalangeal flexion/extension, and grip and tripod pinch strength. Further consensus recommendations were for the assessment of function using a region-specific, upper extremity patient-reported outcome measure (activity and participation), environmental factors, outcome expectation, and illness perception within the patient's unique environmental and social contexts. Treatment recommendations included the use of an orthosis during painful activities, a dynamic stability program (stable C posture, release of tight adductors, and strengthening of stabilizers), patient education, joint protection techniques, adaptive equipment, and functional-based intervention. CONCLUSIONS: The findings describe the consensus of a group of experts and provide a clinical reference tool on the hand therapy assessment and treatment of nonsurgical thumb CMC joint OA.

Clinical and electrophysiological examination of pinch strength in patients with amyotrophic lateral sclerosis.

BACKGROUND: The split-hand concept has highlighted the preferential wasting of the thenar side of the hand in amyotrophic lateral sclerosis (ALS). Our objective is to re-explore pinch grip strength to assess whether it has the potential to be a practical biomarker of ALS. METHODS: We measured different pinch grip strengths (thumb, index, and fifth) using a pinch gauge from both hands of 54 ALS patients and correlated this with the Medical Research Council (MRC) score, the upper-limb component of the revised ALS Functional Rating Scale - Revised (ALSFRS-R) score, and compound muscle action potentials (CMAPs) that comprise the split-hand index. RESULTS: Pinch grip strength using any of the three fingers showed a positive correlation with its corresponding CMAP, MRC grading, and upper-limb ALSFRS-R score. The thumb pinch showed the strongest correlation with the split-hand index and MRC grading. CONCLUSIONS: Pinch grip strength test using a simple gauge deserves further study as a potentially practical biomarker of ALS.

Relationship between ultrasonographic hand muscle thickness measurements and muscle strength following median or ulnar nerve reconstruction.

INTRODUCTION: The aim of this study was to assess the relationship between ultrasonographic hand muscle thickness measurements and hand muscle strength in patients who underwent median or ulnar nerve reconstruction. METHODS: In this prospective, cross-sectional study, intrinsic hand muscle thicknesses were measured using ultrasound with a 4- to 13-MHz linear-array probe. Measurements of hand strength were performed using a dynamometer and a pinchmeter. RESULTS: In the median nerve group (n = 11), a moderate correlation (r = 0.694; P = .018) was observed between lateral pinch strength and transverse thenar thickness. In the ulnar nerve group (n = 11), longitudinal thenar thickness below the flexor pollicis longus tendon was moderate to highly correlated with pinch and handgrip strengths (r = 0.726-0.893; P < .05); whole transverse thenar thickness was moderate to highly correlated with pinch strengths (r = 0.724-0.836; P < .05). DISCUSSION: Sonographic measurements of intrinsic hand muscle thickness may be a useful tool for the assessment and follow-up of patients with median or ulnar nerve injury.

Effect of a Novel Perturbation-Based Pinch Task Training on Sensorimotor Performance of Upper Extremity for Patients With Chronic Stroke: A Pilot Randomized Controlled Trial.

OBJECTIVE: To investigate the effects of perturbation-based pinch task training on the sensorimotor performance of the upper extremities of patients with chronic stroke via a novel vibrotactile therapy system. DESIGN: A single-blinded randomized controlled trial. SETTING: A university hospital. PARTICIPANTS: Patients with chronic stroke (N=19) randomly assigned into either an experimental group or a control group completed the study. INTERVENTIONS: In addition to 10 minutes of traditional sensorimotor facilitation, each participant in the experimental group received 20 minutes of perturbation-based pinch task training in each treatment session, and the controls received 20 minutes of task-specific motor training twice a week for 6 weeks. MAIN OUTCOME MEASURES: The scores for the primary outcome, Semmes-Weinstein monofilament (SWM), and those for the secondary outcomes, Fugl-Meyer Assessment (FMA), amount of use, quality of movement (QOM) on the Motor Activity Log (MAL) scale, and box and block test (BBT), were recorded. All outcome measures were recorded at pretreatment, post treatment, and 12-week follow-up. RESULTS: There were statistically significant between-group differences in the training-induced improvements revealed in the SWM results (P=.04) immediately after training and in the BBT results (P=.05) at the 12-week follow-up. The changes in muscle tone and in the QOM, SWM, and BBT scores indicated statistically significant improvements after 12 sessions of treatment for the experimental group. For the control group, a significant statistical improvement was found in the wrist (P<.001) and coordination (P=.01) component of the FMA score. CONCLUSIONS: This study indicated that the perturbation-based pinch task training has beneficial effects on sensory restoration of the affected thumb in patients with chronic stroke.

Diabetic Peripheral Neuropathy Affects Pinch Strength and Hand Dexterity in Elderly Patients.

Objective: Diabetic peripheral neuropathy (DPN) is one of the most common chronic complications of diabetes, leading to disability and decreased quality of life. In past research and clinical studies, the lower limb function of DPN patients was often the principal subject of research, with little attention given to the upper limb and hand. Our goal was to assess and compare hand function between elderly diabetic patients with DPN and without DPN. Methods: A total of 52 diabetic patients were registered and underwent hand function assessments and electrodiagnostic tests. Dynamometer, pinch meter, Semmes Weinstein monofilaments, and the Purdue Pegboard Test (PPT) were used to assess the patients' grip strength, pinch strength, tactile sensory threshold, and hand dexterity. Results: Compared with the non-DPN group, the elderly DPN group showed worse thumb-middle fingertip pinch strength and thumb-little fingertip pinch strength in the dominant hand (3.50 (2.50, 4.25) vs. 4.50 (3.00, 5.00), p = 0.019; 1.50 (1.00, 2.00) vs. 2.50 (2.00, 3.00), p < 0.001); the elderly DPN group displayed worse thumb-middle fingertip pinch strength, thumb-ring fingertip pinch strength, and thumb-little fingertip pinch strength in the nondominant hand (3.50 (2.00, 4.50) vs. 4.00 (3.00, 5.00), p = 0.013; 2.50 (1.25, 3.00) vs. 3.00 (2.50, 3.50), p = 0.033; 1.00 (0.75, 2.25) vs. 2.50 (2.00, 2.50), p < 0.001). The elderly DPN group scored lower than the non-DPN group on the PPT test of assembly (13.96 ± 5.18 vs. 16.96 ± 4.61, t = 2.212, p = 0.032). Conclusion: Motor function limitation is the principal hand dysfunction in elderly patients with DPN, which is mainly manifested as a decline in fingertip pinch strength and a decrease in hand dexterity. This trial is registered with Clinical Trial Registry no. ChiCTR1900025358.

Validation of a new hand function outcome measure in individuals with Charcot-Marie-Tooth disease.

The symptomatology of Charcot-Marie-Tooth (CMT) disease mainly involves the feet and the hands. To date, there is no consensus on how to evaluate hand function in CMT. The aim of this study is to correlate the data of the engineered glove Hand Test System (HTS) with specific tests and the CMT examination score (CMTES). We analyzed 45 patients with the diagnosis of CMT using HTS, which measures the hand dexterity by specific sequences performed at maximum velocity. We completed the evaluation with the CMTES, tripod pinch and hand grip strength tested by a dynamometer, thumb opposition test (TOT), and Sollerman Hand function test (SHFT), and we conducted a test-retest with 20 normal subjects. Finger tapping (FT) and index-medium-ring-little (IMRL) sequence showed a significant correlation with CMTES (FT: dominant hand (DH): P = .036; non-dominant hand (NDH): P = .033; IMRL: DH: P = .009; NDH: P = .046). TOT correlated with CMTES significantly in both hands (P < .0001). tripod pinch showed a statistically significant correlation with CMTES (DH: P = .002; NDH: P = .005). Correlation between the hand grip and CMTES was significant only in DH (DH: P = .002). SHFT had a significant correlation with the CMTES (DH: P = .002). Test-retest showed a good reliability. HTS parameters correlate with CMTES confirming that this tool is sensitive to the hand deficits. In conclusion, we can state that HTS is a good, simple to use, and objective instrument to evaluate the hand function of CMT patients, but more studies on responsiveness and sensitivity are needed.

Grip force control during object manipulation in cervical myelopathy.

STUDY DESIGN: Cross-sectional research. OBJECTIVES: To objectively evaluate grip force (GF) control while holding a freely movable object in individuals with cervical myelopathy (CM). SETTING: Harunaso Hospital, Takasaki, Japan. METHODS: We studied 52 hands from 26 individuals with CM. Participants performed a grip-and-lift task by pulp pinch using the thumb and index finger before surgery. We monitored individual finger GF (N) during the first 3 s while lifting and holding an object. Correlations between the GF and other clinical tests were evaluated. A multiple stepwise regression analysis was used to examine the contribution of the GF to the severity of clinical symptoms. RESULTS: Thumb GF was negatively correlated with the 10-s test (rs = -0.32), and index finger GF was positively correlated with its cutaneous pressure threshold (rs = 0.34). Multiple regression for the severity of upper extremity symptoms revealed that the model including the GF had a larger adjusted R2 and a lower AIC value than that of conventionally used clinical tests. CONCLUSIONS: These results suggested that the assessment of individual finger GF control could provide an indicator of the clinical severity of upper extremity in individuals with CM.

The impact of diabetic peripheral neuropathy on pinch proprioception.

This study aims to investigate the impact of type 2 diabetes (T2D) and diabetic peripheral neuropathy (DPN) on pinch proprioception and to establish the correlations with sensory impairments. We collected data from a total of 36 participants (healthy, n = 12; T2D without DPN, n = 11; and T2D + DPN, n = 13), all matched for age, 60 ± 6 years. Pinch proprioception was determined through 3 trials of attempts to actively reproduce 15° of pinch position without visual feedback. Target accuracy and precision was compared between groups using Kruskal-Wallis test. Sensation was tested through the two-point discrimination and Semmes-Weinstein monofilaments applied on the fingers. Sensory measures were correlated with pinch proprioception measures via Spearman's rank test. The T2D + DPN group showed significant decrements in accuracy and precision as compared to the T2D-only (p = 0.003 and p = 0.006, respectively) and the healthy groups (both p = 0.002); no significant differences were found between T2D-only and healthy. Spearman's rank showed moderate (r = 0.45-0.66, p < 0.001) correlations between pinch proprioception and sensory measures. Our results showed pinch proprioception disruption in people with T2D + DPN, but not in people with T2D-only. The awareness of pinch proprioceptive deficits is paramount for the safety of individuals with T2D and DPN. Moderate correlations between sensory impairments and pinch proprioceptive deficits suggest that not only superficial/discriminative sensation is implicated in proprioceptive decrements. Other mechanisms such as damage to muscle spindles or central nervous system associated with T2D + DPN warrant further investigations.

Platelet-rich plasma for thumb carpometacarpal joint osteoarthritis in a professional pianist: case-based review.

Thumb carpometacarpal osteoarthritis (TCMC-OA) is a progressively disabling, debilitating condition presenting with thumb base pain and hand functional impairment. Platelet-rich plasma has been used widely for the management of musculoskeletal pathologies, OA being among them. To our knowledge, only a few cases have been previously reported on this topic until now. A 59-year-old male professional pianist presented with chronic, mild onset of right thumb base pain involving a progressive lack of pinch strength in his right hand, and severe difficulties with playing. Three PRP injections were administered to the TCMC joint on a 1-week interval regime. Clinical outcomes were assessed by using the visual analog scale (VAS) for pain, grip and pinch strength, and the Quick-DASH Questionnaire. Functional outcome was excellent according to patient's capability with daily living activities and specific playing demands. At 12 months follow-up, no recurrences or complications were identified, with the musician returning to his previous level of performance 2 weeks before the end of this period. Patient self-reported satisfaction was high and he reported to return to his routine piano activity with no limitations. This case-based review study documents the clinical efficacy of PRP treatment from both functional and perceived-pain perspectives in a professional pianist. Presenting this case, our aim is to draw attention of healthcare providers dealing with TCMC-OA to PRP as a safe, beneficial therapy for this condition which needs further assessment in randomized controlled trials.

Transferring the Motor Branch of the Opponens Pollicis to the Terminal Division of the Deep Branch of the Ulnar Nerve for Pinch Reconstruction.

PURPOSE: With ulnar nerve injuries, paralysis of the first dorsal interosseous (FDI) and the adductor pollicis (ADP) muscles weakens pinch. The likelihood that these muscles will be reinnervated following ulnar nerve repair around the elbow is very low. To overcome this obstacle, we propose a more distal repair: transferring the opponens pollicis motor branch (OPB) to the terminal division of the deep branch of the ulnar nerve (TDDBUN). METHODS: We dissected 10 embalmed hands to study the anatomy of the thenar branches of the median nerve and TDDBUN. We also operated on 3 patients with recent ulnar nerve injuries around the elbow, suturing the ulnar nerve and transferring the OPB to the TDDBUN. Before and after surgery, we measured grasp, key pinch, and pinch-to-zoom strength using dynamometers. Pinch-to-zoom gesture consists of moving the index finger and thumb pulp toward each other for zooming out of an image on screen. Patients were followed for at least 15 months. RESULTS: The thenar branch of the median nerve innervated the abductor pollicis brevis and opponens pollicis in all specimens, but only half the superficial head of the flexor pollicis brevis. The TDDBUN gave off a single motor branch to the transverse head of the ADP, 1 or 2 branches to the oblique head, and a final branch to the FDI. The ratio of myelinated fibers between the OPB and the TDDBUN was 3:5. Relative to the normal side, pinch-to-zoom strength was mostly affected by the ulnar nerve lesion, with strength decreased by 80% to 90%. After surgery, we observed reinnervation of the FDI and an 80% to 90% improvement in pinch-to-zoom strength. CONCLUSIONS: Transferring the OPB to the TDDBUN provided reinnervation of the FDI and ADP, thereby contributing to pinch strength improvement. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic V.

Outcomes After Primary Repair and Staged Reconstruction of Zone I and II Flexor Tendon Injuries in Children.

BACKGROUND: Delayed diagnosis of flexor tendon injury in children is common, and consequent flexor sheath scarring may necessitate a 2-stage reconstruction. Previous studies show variable outcomes after 2-stage flexor reconstruction in children, especially those below 6 years old. We evaluated functional and subjective outcomes of primary repair and staged reconstruction of zone I and II tendon injuries in children under 6 years of age. METHODS: A retrospective chart review identified 12 digits in 10 patients who had undergone surgical treatment of a zone I or II flexor tendon injury. Seven digits had a primary repair and 5 had a 2-stage reconstruction. Time delay from injury to surgery for primary repairs averaged 18 weeks and for 2-stage reconstruction averaged 24 weeks. Outcomes included total active motion, tip pinch and grip strength, sensation, and the Pediatric Outcomes Data Collection Instrument (PODCI). RESULTS: Average follow-up was 8 years. At final follow-up, mean total active and passive motion of the involved digit was similar between the primary reconstruction and staged groups, and 58% had a "good" or "excellent" American Society for Surgery of the Hand; total active motion (ASSH TAM) result (71% in the primary repair group, 40% in the 2-stage reconstruction group). All regained grip and pinch strength equal to the contralateral hand. The average PODCI Upper Extremity score was 99 (99 in the primary repair group, 98 in the 2-stage reconstruction group) and PODCI Global Function score was 94 (97 in the primary repair group, 91 in the 2-stage reconstruction group). No complications occurred. CONCLUSIONS: Our small study demonstrates that both primary repair and 2-stage flexor tendon reconstruction have acceptable long-term functional and subjective outcomes in children below 6 years old, although staged reconstruction had a lower overall ASSH TAM score and subcategorical PODCI scores. Although staged reconstruction has acceptable outcomes in this population, prompt primary repair of flexor tendon injuries in children should always be attempted. LEVEL OF EVIDENCE: Level 4-therapeutic.

Predictors of Hand Dexterity after Single-Digit Replantation.

BACKGROUND: Microsurgical replantation of the thumb and digits has become an increasingly familiar technique in clinical practice worldwide. However, successful digit replantation does not always provide better hand function than revision amputation. Little information is available regarding predictors of motor skill activities of replanted hands. Therefore, we retrospectively evaluated hand dexterity after single-digit replantation at a minimum follow-up of 1 year and analyzed the factors influencing dexterity. METHODS: This retrospective cohort study included 23 patients treated for amputation injuries at our institution from 2014 to 2015. Patients with amputations from Tamai's zone 2 to 5 of the thumb (3 patients), index finger (11 patients), or middle finger (9 patients) who underwent digital replantation surgery and were followed up for more than 1 year were included. Follow-up evaluations were conducted at an average of 23 months postoperatively (range: 13-25 months). We hypothesized that possible factors influencing hand dexterity after single-digit replantation were patient age, injured finger, key pinch strength, Semmes-Weinstein test result, and percentage of total active motion. Relationships between the outcome variable, which was the result of the Purdue Pegboard Test of hand dexterity, and explanatory variables were analyzed using Spearman's correlation coefficient. A p-value of < 0.05 indicated statistical significance. RESULTS: No postoperative complications occurred. Univariate analysis indicated that decreased hand dexterity after single-digit replantation was significantly associated with older age (p = 0.001) and poor recovery of sensation, as shown by the Semmes-Weinstein test (p = 0.012). CONCLUSION: Patient age was a risk factor for low hand dexterity after replantation surgery. Recovery of finger sensitivity enhanced dexterity of motor skill activities following finger replantation surgery.

A Touch-Observation and Task-Based Mirror Therapy Protocol to Improve Sensorimotor Control and Functional Capability of Hands for Patients With Peripheral Nerve Injury.

IMPORTANCE: To develop a practical program in the early phase after nerve repair for more rapid return of function. OBJECTIVE: To investigate the effects of touch-observation and task-based mirror therapy on the sensorimotor outcomes of patients with nerve repair. DESIGN: An assessor-blinded study with a randomized controlled design. SETTING: University hospital. PARTICIPANTS: We recruited 12 patients with median or ulnar nerve repair between the level of midpalm and elbow referred by the plastic surgeons. INTERVENTION: The patients were randomized into touch-observation and task-based mirror therapy or control groups, and both groups received training for 12 wk. OUTCOMES AND MEASURES: The Semmes-Weinstein monofilament (SWM) test, two-point discrimination test, Purdue Pegboard Test (PPT), Minnesota Manual Dexterity Test (MMDT), and pinch-holding-up activity test were assessed at pretreatment, immediately after treatment, and 12 wk after the last treatment. RESULTS: The experimental group showed greater improvements in the results of the pinch-holding-up activity test and the PPT Unilateral Pin Insertion, Bilateral Pin Insertion, and Assembly subtests. However, change on the SWM test revealed no significant difference between the two groups. CONCLUSIONS AND RELEVANCE: Touch-observation and task-based mirror therapy is an effective but low-cost treatment protocol to optimize sensorimotor control and functional capability of the upper limb in patients with peripheral nerve injury.

Percentage difference of hand dimensions and their correlation with hand grip and pinch strength among schoolchildren in Saudi Arabia.

AIMS: The study aimed to assess the percentage difference of hand dimensions and their correlation with grip and pinch strength among school children in Saudi Arabia. MATERIALS AND METHODS: Anthropometric measurements, hand dimensions, grip, and pinch strength measurements were obtained from 200 healthy schoolchildren in both genders aged 6-16 years. A Jamar electronic handgrip dynamometer was used to measure handgrip strength in kg. Pinch dynamometer was used to measure the two-point pinch strength, three-point pinch strength and lateral pinch strength in kg. Hand circumference was measured following hand arch at the maximum palm level. Hand span from the tip of the thumb to the tip of the little finger with the hand opened as broad as possible. Hand length from the tip of the middle finger to the midline of the distal wrist crease. Palm length from the distal wrist crease to the base of the middle finger. RESULTS: The percentage of difference of hand dimensions between both the genders was statistically significant. Both handgrip and pinch strength were significantly correlated with anthropometric measurements and hand dimensions. Body mass index had mild correlation with both handgrip strength and pinch strength (P < 0.05). Age, hand circumference, hand span, hand length and palm length had moderate to strong correlation with both grip and pinch strength (P < 0.01). CONCLUSION: The current study provides a source of perspective reference values in clinical settings for hand dimensions. The present study showed significant correlations with handgrip and pinch grip strengths among schoolchildren in Saudi Arabia.

Dubious space for Artelon joint resurfacing for basal thumb (trapeziometacarpal joint) osteoarthritis. A systematic review.

Introduction: Trapeziometacarpal arthritis is a common and disabling condition. There is no evidence in the literature of superiority of one surgical procedure over others. Several prosthetic implants have been introduced to preserve joint mobility. Sourced of data: We searched the on Medline (PubMed), Web of Science and Scopus databases using the combined keywords 'artelon', 'thumb', 'carpometacarpal', 'trapeziometacarpal' and 'rhizoarthrosis'; 11 studies were identified. Areas of agreement: The use of Artelon implant is not recommended because of its high revision rate and worse outcomes compared to conventional techniques. Areas of controversy: Inert materials subjected to compressive and shearing forces could produce debris and subsequent inflammatory response. There is debate in the published scientific literature regarding the role of preoperative antibiotic profilaxis and post-surgery inflammatory response. Growing points: Standard techniques such as trapeziectomy alone or combined with interposition or suspensionplasty offer effective treatment for thumb basal joint arthritis. Areas timely for developing research: Several prosthetic implants show promising results in terms of pain relief and functional request, but there is a need of long-term randomized controlled trials to demonstrate their equivalence, and eventually superiority, compared to standard techniques.

Clinical and Ultrasonic Evaluation of the Thumb: Comparison of Young Adults With and Without Thumb Pain With Text Messaging.

OBJECTIVE: The aim of this study was to compare clinical and ultrasound findings of thumb joints in young adults with and without thumb pain associated with text messaging. METHODS: In this case-control study, 117 students with thumb pain associated with text messaging were evaluated clinically and with ultrasound analysis of the thumb. Age- and sex-matched controls received ultrasound evaluation to note any subclinical changes. RESULTS: Clinical examination in the cases identified tenderness most commonly in the metacarpophalangeal joints, followed by the carpometacarpal joints, and then the interphalangeal joints. Tenderness was noted in the web space and the anatomic snuff box. Hypermobility on the Beighton scale was recorded as 2. Grind tests were positive in 21% of participants. Grip strength did not differ, but lateral and tip pinch strength were significantly reduced in the cases compared with controls. Fluid was detected in the metacarpal joints by ultrasound but not in the carpometacarpal or interphalangeal joints. No changes were detected in the controls. CONCLUSION: Clinical examination indicated involvement of all joints of the thumb, but ultrasound evaluation could identify changes only in metacarpal joints, indicating signs of possible subclinical changes taking place in the thumb in these participants as a result of repetitive use.

Open-source 3D printed sensors for hand strength assessment: Validation of low-cost load cell and fabric sensor-based systems.

BACKGROUND/AIM: Pinch and grip strength assessment is commonly performed in occupational therapy practice. However, the typically utilised methods are limited to pinch or grip dynamometers and do not readily translate to handling everyday objects. With the advent of consumer-grade 3D printing and low-cost sensor systems, the possibilities for creating customised assessment devices are expanding. As a first step in determining the validity of low-cost sensor systems, their data must be compared to a gold standard. Consequently, this study examined the criterion validity of two such systems for measuring pinch strength, specifically a small load cell and pressure-sensing fabric, with a mechanical pinch gauge. METHODS: A total of 33 participants performed strength tests using a mechanical pinch grip device, which had a plastic 3D printed cover with a pressure-sensing fabric overlaid on it to allow for simultaneous criterion validation, and a small load cell with a plastic 3D printed casing designed for comfortable pinch grip assessment. RESULTS: The simultaneously assessed fabric sensor and mechanical pinch grip device showed excellent absolute (ICC2,k  = 0.94) and relative (Pearson's R = 0.90) agreement. Both devices showed similar excellent relative (R > 0.75) agreement with the load cell despite non-simultaneous assessment. These findings indicate that 3D printed sensors incorporating a load cell and a pressure-sensing fabric can be used to replicate a pinch grip assessment performed with a mechanical pinch gauge. CONCLUSIONS: This study lays the foundation for these sensor systems to be modified for use as assessment tools during the performance of functional tasks using everyday objects. Additionally, because both systems generate real-time force data they could be used for biofeedback as part of rehabilitation and strengthening programs. To aid uptake and future research using these systems, the 3D print models, step-by-step hardware design and software programs used are provided in an open-source format at www.rehabtools.org/otsensors.html.

Biomechanics and Pinch Force of the Index Finger Under Simulated Proximal Interphalangeal Arthrodesis.

PURPOSE: To analyze the effect of simulated proximal interphalangeal (PIP) joint arthrodesis on distal interphalangeal (DIP) joint free flexion-extension (FE) and maximal voluntary pinch forces. METHODS: Five healthy subjects were tested with the PIP joint unconstrained and constrained to selected angles to produce (1) free FE movements of the DIP joint at 2 selected angles of the metacarpophalangeal joint, and (2) maximal voluntary tip (thumb and index finger) and chuck (thumb, index, and middle fingers) pinch forces. Kinematic data from a motion analysis system, pinch force data from a mechanical pinch meter, and electromyography (EMG) data recorded from 2 flexor and extensor muscles of the index finger were collected during free FE movements of the DIP joint and pinch tests for distinct PIP joint constraint angles. RESULTS: The EMG root mean square (RMS) values of the flexor digitorum profundus (FDP) and extensor digitorum (ED) did not change during free FE of the DIP joint. The extension angle of the range of motion of the DIP joint changed during free FE. It increased as the PIP constraint angle increased. The EMG RMS value of FDP and ED showed maximum values when the PIP joint was unconstrained and constrained at 0° to 20° of flexion during tip and chuck pinch. Neither the index finger metacarpophalangeal and DIP joint positions nor pinch force measurements differed with imposed PIP joint arthrodesis. CONCLUSIONS: The PIP joint arthrodesis angle affects DIP joint extension. A minimal overall impact from simulated PIP arthrodesis in muscle activity and pinch force of the index finger was observed. The EMG RMS values of the FDP and ED revealed that a PIP arthrodesis at 0° to 20° of flexion leads to a more natural finger posture during tip and chuck pinch. CLINICAL RELEVANCE: This study provided a quantitative comparison of free FE motion of the DIP joint, as well as FDP and ED forces during pinch, under simulated index finger PIP arthrodesis angles.