Analysis of the alpha activity envelope in electroencephalography in relation to the ratio of excitatory to inhibitory neural activity.

Alpha waves, one of the major components of resting and awake cortical activity in human electroencephalography (EEG), are known to show waxing and waning, but this phenomenon has rarely been analyzed. In the present study, we analyzed this phenomenon from the viewpoint of excitation and inhibition. The alpha wave envelope was subjected to secondary differentiation. This gave the positive (acceleration positive, Ap) and negative (acceleration negative, An) values of acceleration and their ratio (Ap-An ratio) at each sampling point of the envelope signals for 60 seconds. This analysis was performed on 36 participants with Alzheimer's disease (AD), 23 with frontotemporal dementia (FTD) and 29 age-matched healthy participants (NC) whose data were provided as open datasets. The mean values of the Ap-An ratio for 60 seconds at each EEG electrode were compared between the NC and AD/FTD groups. The AD (1.41 ±0.01 (SD)) and FTD (1.40 ±0.02) groups showed a larger Ap-An ratio than the NC group (1.38 ±0.02, p<0.05). A significant correlation between the envelope amplitude of alpha activity and the Ap-An ratio was observed at most electrodes in the NC group (Pearson's correlation coefficient, r = -0.92 ±0.15, mean for all electrodes), whereas the correlation was disrupted in AD (-0.09 ±0.21, p<0.05) and disrupted in the frontal region in the FTD group. The present method analyzed the envelope of alpha waves from a new perspective, that of excitation and inhibition, and it could detect properties of the EEG, Ap-An ratio, that have not been revealed by existing methods. The present study proposed a new method to analyze the alpha activity envelope in electroencephalography, which could be related to excitatory and inhibitory neural activity.

Utility of severity scoring systems for mangled upper limb salvage: A systematic review and meta-analysis.

BACKGROUND: The purpose of scoring systems is to aid in the decision-making process of whether to salvage or amputate mangled extremities, but their efficacy for upper limbs is uncertain. In this study, we examined the predictive potential of scoring systems for upper limb salvage. METHODS: Two investigators undertook a systematic search of 3 leading databases for English or Japanese literature from 1985, when the first scoring system to evaluate mangled extremities was proposed, until January 2022. To be eligible, studies must have had upper extremity limb salvage or amputation as an outcome, and identified the scoring system used and treatment outcome in individual cases. RESULTS: Ten studies (N = 338) of the Mangled Extremity Scoring System (MESS) were ultimately included in the meta-analysis. The pooled sensitivity and specificity were 0.95 (95 % CI = 0.69-0.99) and 0.81 (0.65-0.91), respectively. The area under the hierarchical summary receiver operating characteristic curve was 0.95 (0.93-0.97). A subgroup analysis showed lower specificity in isolated vascular injuries. Scoring systems other than MESS were ineligible for the quantitative synthesis because none were examined in an adequate number of publications. CONCLUSION: The pooled sensitivity and specificity for MESS were comparable to those reported for the lower extremities. The specificity suggests that limb salvage was achieved in at least 20 % of the patients whose MESS was above the threshold beyond which amputation is indicated. Given the likelihood of upper extremity functional limitations following amputation and the drawbacks of prostheses, we conclude that current scoring systems poorly predict salvageability of a mangled upper extremity and should not be used to justify amputation.

Do triangular fibrocartilage complex foveal injuries affect the clinical outcome of ulnar shortening osteotomy for ulnar impaction syndrome?

BACKGROUND: Ulnar shortening osteotomy (USO), as its name implies, is used to shorten the ulna. It subsequently tightens the triangular fibrocartilage complex (TFCC) and ulnar wrist. TFCC foveal insertion is a primary stabilizer of the distal radioulnar joint. It is unclear whether USO is effective in TFCC foveal injuries. The purpose of this study was to review the clinical outcomes of ulnar shortening osteotomies with and without TFCC foveal injuries. METHODS: We retrospectively reviewed patients with ulnar wrist pain treated with USO and wrist arthroscopy including the distal radioulnar joint (DRUJ). Sixty-five patients were included in this study. An algorithm was used to guide surgical decision-making. After arthroscopic confirmation of ulnar impaction syndrome, we performed USO with a locking compression plate (mean length of shortening, 2.7 mm; range, 1-7.5 mm). The flattened TFCC disc due to ulnar shortening was confirmed arthroscopically. If the DRUJ was unstable after USO, we repaired the TFCC foveal insertion. RESULTS: There were 32 post-traumatic and 33 idiopathic cases. We detected TFCC disc injuries in 34 wrists and TFCC foveal injuries in 33 wrists; both types were found in 15 wrists. TFCC foveal injuries were not significantly correlated with patient age, history of trauma, or clinical outcome. Most patients showed good clinical outcomes; 31 of 65 patients had preoperative DRUJ instability, with a significant number having foveal but not disc injuries. CONCLUSION: USO achieved reasonable outcomes, even in patients with TFCC foveal injuries. In cases demonstrating ulnar impaction, USO should be prioritized over TFCC repair.

Mast cell presence in tendon sheaths of trigger fingers: implications on pathogenesis and clinical presentation.

Trigger finger is a common hand disorder; however, its pathogenesis remains unknown. In this study, we aimed to investigate mast cells, fibroblast activators that synthesize collagen, in the tendon sheaths of trigger fingers. We investigated the presence of mast cells and their association with changes in the collagen content of the tendon sheath and clinical data. We performed a multicenter prospective study of 77 adult patients with trigger finger who had undergone resection of the first annular pulley between August 2012 and January 2020. The tendon sheath was immunostained with an anti-tryptase antibody to confirm mast cell presence. The percentage of collagen in the tendon sheath was determined by picrosirius red staining observed through a polarization microscope. The clinical data, including the duration from symptom onset to surgery, severity, pain numerical rating scale, and Hand20 scores, were evaluated. Tryptase-positive mast cells were recognized in 83.5% of all specimens. The mast cell presence group (Group P) had a significantly higher percentage of type-3 collagen in the tendon sheath than the non-mast cell presence group (Group N) (Group P, 15.6%; Group N, 12.7%; p = 0.03). Moreover, Group P had significantly higher pain numerical rating scale (Group P; 5, Group N; 3, p = 0.04) and Hand20 (Group P; 35.5, Group N; 13.0, p = 0.01) scores than Group N. These findings suggest that mast cell presence in the tendon sheath of the trigger finger is related to the pathology and clinical symptoms of trigger finger.

Questionnaire survey about the effects of new lifestyles during the pandemic of COVID-19 on upper limb diseases.

BACKGROUND: The novel coronavirus (COVID-19) that emerged in 2019 and spread globally in 2020 has resulted in the imposition of lockdowns or a state of emergency in many cities worldwide. In Japan, a "new lifestyle" is being advocated. We hypothesize that the new lifestyle has changed people's use of their upper limbs during the COVID-19 pandemic. Therefore, through this questionnaire study, we aimed to determine the factors associated with exacerbation of symptoms during the pandemic and to investigate the current status of patients who require hand surgery. METHODS: This study was a prospective multi-center questionnaire survey. This study was conducted in Japan from December 2020 to July 2021 at university and general hospitals in nine prefectures. A questionnaire was administered to patients who visited a hospital with symptoms of nerve entrapment syndrome, osteoarthritis, or tenosynovitis. RESULTS: A total of 502 patients with a mean age of 63.8 years responded. The 240 patients who experienced exacerbation (exacerbated and markedly exacerbated) were compared with other patients (unchanged, improved, and markedly improved). An increase in the time spent on personal computers and smartphones was associated with exacerbation of hand symptoms. Patients who wanted to undergo surgery but were postponed due to COVID-19 accounted for 23.5% of the outpatients. The mean scores for pain, jitteriness, and anxious depression in these patients were significantly higher than those of patients who did not want surgery. CONCLUSIONS: Our results suggest that an increase in the time spent on personal computers and smartphones is associated with exacerbation of hand symptoms during the COVID-19 pandemic. Patients who wanted to undergo surgery but were postponed by COVID-19 experienced greater pain, jitteriness, and anxious depression.

A systematic review assessing the effectiveness of hand therapy programmes in adults with burns using the International Classification of Functioning, Disability and Health framework.

This systematic review aimed to confirm the effectiveness of hand therapy programmes using the International Classification of Functioning, Disability and Health framework for each of the three phases of the wound healing process in adults with burns. A systematic review was conducted to determine the efficacy of different hand therapy programmes in the management of burnt hands. Two independent reviewers conducted a literature search using the PubMed and Cumulative Index to Nursing and Allied Health Literature databases for original articles reporting effectiveness of hand therapy programmes for adults with burns. Only randomized and non-randomized controlled trials were selected using the Mixed Methods Appraisal Tool. Demographic and clinical data including medical history, burn depth, and hand therapy programme were extracted. Outcome measures were reviewed based on the International Classification of Functioning, Disability and Health framework for acute, convalescence, and chronic phases of rehabilitation. Sixteen articles and 15 hand therapy programmes were identified, which included studies showing improvements in different parameters in the framework. In the acute and convalescence phases, improvements were found in health condition, body functions and structures, activities, and participation. In the chronic phase, improvements were shown only in body functions and structures. Environmental factors in the framework were not reported for all the phases. This review demonstrated the efficacy of hand therapy programmes in adults with burns in terms of the health condition, body function, activities, and participation during acute and convalescence phases but only the body function in the chronic phase.

Can on-top plasty for atypical radial polydactyly realize a functional reconstruction corresponding to appearance?

On-top plasty may be the best option for reconstructing atypical radial polydactyly, consisting of a developed distal portion in one thumb and a developed proximal portion in the other thumb. However, it is unclear if patients can gain thumb function corresponding to the reconstructed appearance. We performed a retrospective bibliographic review to summarize the current literature and present our department's on-top plasty experiences. Over the last ten years, our department performed three on-top plasty radial polydactyly reconstructions. We surveyed the appearance and use of the reconstructed thumb and the patient's satisfaction level during postoperative follow-up. We also retrieved published case reports describing on-top plasty for polydactyly reconstruction to compare with our cases. Our patients had an acceptable thumb appearance and were satisfied with the gained function of the thumb. However, two patients required revision surgery. We found 11 studies in the literature describing on-top plasty for polydactyly treatment, four of which reported a limited range of thumb motion, but no patient or their family complained about the result. Most patients who undergo on-top plasty for radial polydactyly can expect a fair to good appearance after surgery. Although instability or limitation of the joint arc is possible, the reconstruction satisfies patients regarding function and appearance.

Postoperative peripheral neuropathy considered to be induced by surgical stress.

BACKGROUND: Most surgeons are unaware that idiopathic neuropathy, which occurs independently of mechanical injury, can present as postoperative peripheral neuropathy. The aim of this study was to reveal the presence of postoperative neuropathy considered to be induced by surgical stress and to make surgeons aware that idiopathic neuropathy can occur postoperatively. METHODS: We conducted a survey among orthopedic surgeons regarding patients with postoperative neuropathies of unknown cause. For each case, the type of neuropathy, preceding surgery and anesthesia, patient background, clinical findings, and clinical course were investigated. RESULTS: Seven patients were identified. The mean time from surgery to the onset of neuropathy was 9.3 days (range 1-15 days). Five of the patients fully recovered spontaneously within 1 year, while the remaining two underwent neurolysis. One patient presented with hourglass-like constrictions in the radial nerve. No inflammatory cells were found in the epineurium of the affected nerve. CONCLUSIONS: Although it is rare, postoperative idiopathic neuropathy occurs in clinical practice, and it is crucial that surgeons recognize the existence of this neuropathy to elucidate its pathogenesis as well as to reduce the risk of litigation.

An intraoperative small distractor for non-open reduction and intramedullary fixation of pediatric displaced diaphyseal forearm fractures.

This report describes technical tools for the treatment of pediatric displaced and unstable diaphyseal forearm fractures, which are difficult to treat by manual closed reduction. During intramedullary fixation with Kirchner wires, we propose our original small distractor as an intraoperative distraction apparatus without open reduction. This apparatus is made using parts of the Ilizarov external fixator. Apart from general external fixation devices, our apparatus is adequate for the effective shortening and lateral dislocation of the fracture site. This adequacy is not only because of the three-dimensional control by ball joints but also owing to the gradual adjustment structure of the Quick adjust strut (Orthofix, Verona, Italy), which allows tight and fine stretching, thus making the distractor an effective reduction tool. Our findings show the feasibility and usefulness of our reduction technique and small distractor. Our small distractor is a useful intraoperative distraction apparatus without open reduction for pediatric displaced and unstable diaphyseal forearm fractures that cannot be treated by manual closed reduction. In this report, we describe the distractor, the closed reduction technique, and the clinical results of four representative cases.

Radial Osteotomy for Kienböck Disease: Clinical and Radiological Comparison between Younger and Older Patients.

Background: The usefulness of radial osteotomy for older patients remains unclear. The purpose of this study was to compare the clinical and radiological outcomes of radial osteotomy with volar locking plate between younger and older patients with Kienböck disease stages II to IIIB. Methods: This was a retrospective comparative study of 21 consecutive patients treated at our department. Lichtman's classification was used for staging, and four patients had stage II, six patients had stage IIIA, and 11 patients had stage IIIB disease. We divided them into two groups to compare the radiological and clinical results between younger (younger than 40 years) and older patients. The mean follow-up periods in the younger and older groups were 4 and 3.6 years, respectively. For radiological assessment, we evaluated the carpal height ratio (CHR), Stahl index, and union of the fractured lunate. For clinical assessment, we examined the range of motion of the wrist, grip strength, numeric rating scale (NRS) for pain, and the patient-reported Hand20 score preoperatively and at the final follow-up. Results: There were 12 patients in the younger group with a mean age of 23 years (range, 12-37 years), and 9 in the older group with a mean age of 56 years (range, 40-74 years). There were no intra- and post-operative complications in either group. Radiological improvement, including CHR, Stahl index, and union of the fractured lunate, was more common in the younger group than in the older one, as was the case for clinical improvement. However, even in the older group, significant clinical improvement, including the range of motion of the wrist, NRS for pain, and the Hand20 score, was seen postoperatively. Conclusions: Radial osteotomy appears to be a safe and reliable option in older symptomatic patients with Kienböck disease stages II to IIIB.

Ulnar Parametacarpal Flap for Small Finger Avulsion Injury.

In difficult cases of replantation following small finger avulsion injury, in which amputation occurs at the proximal interphalangeal joint, the ulnar parametacarpal island flap, rotated 180° (propeller flap), can be used as an alternative method for covering a skin defect of the proximal phalanx. This flap can prevent metacarpophalangeal joint dysfunction and additional finger shortening. We propose the use of an ulnar parametacarpal flap for this purpose and report the outcomes of two successful cases treated with this method and followed up for 12 months.

Choice of control group treatments in hand osteoarthritis trials: A systematic review and meta-analysis.

OBJECTIVES: To assess how patient characteristics and study design influence the effectiveness of control interventions in hand OA trials. METHODS: The study protocol was registered in PROSPERO (CRD42020163473). Two authors independently searched four electronic databases from their inception to December 31, 2019. Randomized and non-randomized controlled hand OA trials were included if pain intensity was assessed using a validated scale. We allocated control groups into one of the following: placebo, add-on treatment, no treatment, or active treatment. The standardized mean differences (d) of pain, as well as subjective function and hand strength, were pooled with 95% confidence intervals (CI) and 90% prediction intervals using random-effects models. Meta-regression and post-hoc subgroup analyses were performed to investigate which factors potentially impacted placebo analgesia and between-study heterogeneity. RESULTS: Thirty-one placebo, 11 add-on, 12 no-treatment, and 10 active-treatment controls were included in meta-analyses. Effective pain relief was observed in placebo (d = -0.50, 95% CI -0.63 to -0.37), add-on (d = -0.35, 95% CI -0.59 to -0.12), and active-treatment (d = -0.92, 95% CI -1.35 to -0.48) groups. In subjective function, these treatments had smaller but beneficial effects; hand strength, contrastingly, was not improved. Placebo effects were larger when flare designs were used (d = -0.96) and more homogeneous when minimum pain thresholds were set (d = -0.46, 90% prediction intervals -0.79 to -0.14). CONCLUSION: Placebo, add-on, and active control treatments were more effective than the no treatment control in relieving hand pain and improving subjective function. By choosing minimum pain thresholds and flare requirements at patient enrollment, moderate pain relief may be replicated among control participants in future randomized placebo-controlled trials.

Chronic pain-related cortical neural activity in patients with complex regional pain syndrome.

Quantitative objective measurement of chronic pain is important. We elucidated chronic pain-related cortical neural activity and neural connectivity among pain-related brain regions in complex regional pain syndrome (CRPS). Resting-state magnetoencephalography recordings were performed. Cortical current density and neural connectivity, revealed by amplitude envelope correlation (AEC), were estimated on standardized brain magnetic resonance imaging. Intra-experiment pain was assessed subjectively using a visual analogue scale (VAS). The correlation between current density and VAS scores was calculated for the occipital areas and pain-related cortices. Current density in the primary (SI) and secondary (SII) somatosensory cortex and precuneus in both hemispheres was negatively correlated with the pain VAS score. The AEC and VAS values were significantly correlated for the SII and the precuneus and for the SII and insular cortex in the alpha frequency band in the right hemisphere. In the theta frequency band, the AEC and VAS values correlated for the SII and posterior cingulate cortex in the right hemisphere. Our results suggested that disruption of pain processes and functions in the default mode network occurs in CRPS. Our method targeting the neural mechanism of pain has the potential to offer a clinically objective means of evaluating it.

Innervation of Meissner's corpuscles and Merkel -cells by transplantation of embryonic dorsal root ganglion cells after peripheral nerve section in rats.

Transplantation of embryonic motor neurons has been shown to improve motor neuron survival and innervation of neuromuscular junctions in peripheral nerves. However, there have been no reports regarding transplantation of sensory neurons and innervation of sensory receptors. Therefore, we hypothesized that the transplantation of embryonic sensory neurons may improve sensory neurons in the skin and innervate Merkel cells and Meissner's corpuscles. We obtained sensory neurons from dorsal root ganglia of 14-day rat embryos. We generated a rat model of Wallerian-degeneration by performing sciatic nerve transection and waiting for one week after. Six months after cell transplantation, we performed histological and electrophysiological examinations in naïve control, surgical control, and cell transplantation groups. The number of nerve fibers in the papillary dermis and epidermal-dermal interface was significantly greater in the cell transplantation than in the surgical control group. The percent of Merkel cells with nerve terminals, as well as the average number of Meissner corpuscles with nerve terminals, were higher in the cell transplantation than in the surgical control group, but differences were not significant between the two groups. Moreover, the amplitude and latency of sensory conduction velocity were evoked in rats of the cell transplantation group. We demonstrated that the transplantation of embryonic dorsal root ganglion cells improved sensory nerve fiber number and innervation of Merkel cells and Meissner's corpuscles in peripheral nerves.

Osteoid osteoma of the wrist misdiagnosed as de Quervain's tenosynovitis due to normal X-ray at the first visit: A case report.

INTRODUCTION: Osteoid osteomas are benign bone tumors that can occur in various bones throughout the body but are mainly found in the long bones. PRESENTATION OF THE CASE: We report the case of a patient who had been treated for more than three years for a case of de Quervain's tenosynovitis due to tenderness in the first compartment of the right wrist joint. An X-ray on his first visit to a clinic was normal, but it was eventually discovered that he had an osteoid osteoma of the wrist. DISCUSSION: The age of onset and gender proclivity of each disease should be considered. An X-ray should be taken in cases such as this, even to diagnose tendonitis. When any symptom, such as pain, has lingered for a long time and resisted treatment, we must reconsider the diagnosis. In patients with a low risk of tendonitis, it is essential to consider the possibility of other diseases if there is no improvement after treatment. As this patient's tumor was missed on the initial X-ray, it grew to a mature case of osteoid osteoma in three years. CONCLUSION: We experienced a very educational case of osteoid osteoma of the wrist misdiagnosed as de Quervain's tenosynovitis.

Risk factors for rupture of extensor tendons in the rheumatoid wrist.

This study assessed the risk factors for spontaneous extensor tendon rupture in the rheumatoid wrist. The rupture group consisted of 25 wrists that had rupture of the extensor tendons and later received tendon reconstruction. The non-rupture group included 77 rheumatoid wrists without extensor tendon rupture. We assessed patients' pain at the distal radioulnar joint and swelling in the extensor tendon compartments clinically, matrix metalloproteinase-3 level in blood samples, and radiographic findings. We found that swelling in the extensor tendon compartments, the scallop sign, and severe dorsal subluxation are significantly associated with spontaneous extensor tendon rupture, but serum matrix metalloproteinase-3 level is not.Level of evidence: IV.

Compatibility of magnetic resonance imaging in patients with orthopedic implants: manufacturer questionnaires.

In clinical practice, surgeons have stated that magnetic resonance imaging (MRI) can be performed in patients with titanium alloy implants. However, manufacturers and distributors of many implants may not comply with this common practice. As such, this study aimed to investigate manufacturers' views on MRI use in patients fitted with their implants. The questionnaire survey was conducted between May and August 2018. Is your product compatible with MRI? ( ) Select from (1) to (3). In case of (1) or (2), up to ( ) Tesla. (1) MRI can be performed even at the sites of implanted fixators. (2) MRI can be performed at sites without implanted fixators. (3) MRI cannot be performed, or the manufacturer does not approve MRI use (cannot issue a certificate). The questionnaire forms were sent to 12 manufacturers, and the response rate was 100%. Manufacturers responded that they could not publicly allow MRI use in patients with their products. These findings do not conclude that MRI cannot be performed in such patients. This survey revealed that currently decisions regarding MRI use is left to the treating physicians. This situation poses a great problem for medical safety and imposes a substantial burden on physicians. As many problems remain in the field of orthopedic surgery, manufacturers of implants should proactively manage issues surrounding the usage of MRI.

Disturbance of somatotopic spatial cognition and extra-territorial pain in carpal tunnel syndrome.

BACKGROUND: Several studies on carpal tunnel syndrome have reported pain that exists beyond the median nerve territory of the affected hand. However, the mechanism is unknown. PURPOSE: We investigated the cause of extra-territorial pain by the analysis of clinical assessments and cortical activity using magnetoencephalography. METHODS: To compare patients with and without extra-territorial pain, fourteen patients with carpal tunnel syndrome were assessed using clinical examination, such as patients' profile, paresthesia, physical tests, and psychological tests. The physical assessment included tactile threshold and static and moving two-point discrimination sensations on digital pulp. Neural activation in the cerebral cortex was also measured using z-scores calculated by magnetoencephalography. RESULTS: Among fourteen patients, ten patients had pain in the affected median nerve territory only and four patients had extra-territorial pain. When comparing the groups, the static and moving two-point discrimination sensation values in patients with extra-territorial pain were larger than those of patients without the pain (p < 0.05). The supra-marginal gyrus, mid-part of the precentral sulcus, angular gyrus in the left hemisphere, bilateral sensorimotor areas for legs, and bilateral isthmus-cingulate areas showed larger z-scores in patients with extra-territorial pain than in patients without the pain (p < 0.05). CONCLUSIONS: The static and moving two-point discrimination sensations signify the ability of tactile spatial acuity. Bilateral sensorimotor areas were activated in sites that were not the hand. Furthermore, the inferior parietal lobule in the left hemisphere, which synthesizes and integrates multiple sensations showed high activation. Our findings suggested that the mechanism of extra-territorial pain was associated with dysfunction of spatial cognition.

Electroencephalographic Functional Connectivity With the Tacit Learning System Prosthetic Hand: A Case Series Using Motor Imagery.

We previously created a prosthetic hand with a tacit learning system (TLS) that automatically supports the control of forearm pronosupination. This myoelectric prosthetic hand enables sensory feedback and flexible motor output, which allows users to move efficiently with minimal burden. In this study, we investigated whether electroencephalography can be used to analyze the influence of the auxiliary function of the TLS on brain function. Three male participants who had sustained below-elbow amputations and were myoelectric prosthesis users performed a series of physical movement trials with the TLS inactivated and activated. Trials were video recorded and a sequence of videos was prepared to represent each individual's own use while the system was inactivated and activated. In a subsequent motor imagery phase during which electroencephalography (EEG) signals were collected, each participant was asked to watch both videos of themself while actively imagining the physical movement depicted. Differences in mean cortical current and amplitude envelope correlation (AEC) values between supplementary motor areas (SMA) and each vertex were calculated. For all participants, there were differences in the mean cortical current generated by the motor imagery tasks when the TLS inactivated and activated conditions were compared. The AEC values were higher during the movement imagery task with TLS activation, although their distribution on the cortex varied between the three individuals. In both S1 and other brain areas, AEC values increased in conditions with the TLS activated. Evidence from this case series indicates that, in addition to motor control, TLS may change sensory stimulus recognition.

Cross-cultural translation, adaptation and validation of a Japanese version of the functional index for hand osteoarthritis (J-FIHOA).

BACKGROUND: Hand osteoarthritis (OA) has a wide spectrum of clinical presentations and physical function is one of the core domains where patients suffer. The Functional Index for Hand Osteoarthritis (FIHOA) is a leading assessment tool for hand OA-related functional impairment. Our objective was to make a Japanese version of FIHOA (J-FIHOA) and validate it among Japanese hand OA patients. METHODS: Forward and backward translation processes were completed to create a culturally adapted J-FIHOA. A prospective, observational multicenter study was undertaken for the validation process. Seventeen collaborating hospitals recruited Japanese hand OA patients who met the American College of Rheumatology criteria. A medical record review and responses to the following patient-rated questionnaires were collected: J-FIHOA, Hand20, Health Assessment Questionnaire (HAQ), numerical rating scale for pain (NRS pain) and Short Form 36 Health Survey (SF-36). We explored the structure of J-FIHOA using factor analysis. Cronbach's alpha coefficients and item-total correlations were calculated. Correlations between J-FIHOA and other questionnaires were evaluated for construct validity. Participants in clinically stable conditions repeated J-FIHOA at a one- to two-week interval to assess test-retest reliability. To evaluate responsiveness, symptomatic patients who started new pharmacological treatments had a 1-month follow-up visit and completed the questionnaires twice. Effect size (ES) and standardized response mean (SRM) were calculated with pre- and post-treatment data sets. We assessed responsiveness, comparing ES and SRM of J-FIHOA with other questionnaires (construct approach). RESULTS: A total of 210 patients participated. J-FIHOA had unidimensional structure. Cronbach's alphas (0.914 among females and 0.929 among males) and item-total correlations (range, 0.508 to 0.881) revealed high internal consistency. Hand20, which measures upper extremity disability, was strongly correlated with J-FIHOA (r = 0.82) while the mental and role-social components of SF-36 showed no correlations (r = - 0.24 and - 0.26, respectively). Intraclass correlation coefficient for test-retest reliability was 0.83 and satisfactory. J-FIHOA showed the highest ES and SRM (- 0.68 and - 0.62, respectively) among all questionnaires, except for NRS pain. CONCLUSIONS: Our results showed J-FIHOA had good measurement properties to assess physical function in Japanese hand OA patients both for ambulatory follow-up in clinical practice, and clinical research and therapeutic trials.