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.

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.

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.

Interleukin-6 secretion by fibroblasts in carpal tunnel syndrome patients is associated with trigger finger and inhibited by tranilast.

INTRODUCTION: In this study we aimed to clarify the association between interleukin-6 (IL-6) secretion in fibroblasts in carpal tunnel syndrome (CTS) patients and their biophysical parameters, including association with trigger finger and whether tranilast inhibits IL-6 secretion in fibroblasts. METHODS: Fibroblasts were obtained from tenosynovial tissue harvested from idiopathic CTS patients undergoing carpal tunnel release and tenosynovectomy and cultured in media containing tranilast with or without tumor necrosis-α (TNF-α) or interleukin-1ß (IL-1ß). Their proliferation was evaluated and secreted IL-6 levels and IL-6 mRNA expression were quantified. Correlations between IL-6 concentration and patient characteristics were examined. RESULTS: IL-6 secretion was significantly associated with trigger finger (P = .001). Tranilast inhibited fibroblast proliferation in a dose-dependent manner and suppressed IL-6 secretion. DISCUSSION: IL-6 overproduction in tenosynovial tissue may account for the association between CTS and trigger finger. Future studies should investigate whether tranilast can be used to treat patients with CTS.

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.

Differences in characteristics of carpal tunnel syndrome between male and female patients.

BACKGROUND: Sex difference is known to be a risk factor of carpal tunnel syndrome. However, sex differences with regard to the clinical presentation of carpal tunnel syndrome have not received much attention. Thus, this study aimed to detect any difference in the characteristics of carpal tunnel syndrome between male and female and thereby add new insights into disease prevention. METHODS: A total of 647 patients (male 193 hands and female 454 hands) with carpal tunnel syndrome who underwent endoscopic or open carpal tunnel release were retrospectively reviewed. The average age at time of surgery was 66 years. Clinical and electrophysiological data of all patients were collected. Six medical conditions, including trigger finger, diabetes mellitus, hemodialysis, hyperlipidemia, hypertension, and obesity were also investigated. RESULTS: A significant difference was found in the distribution of comorbidities between the male and female groups. Particularly, the prevalence of diabetes mellitus, hemodialysis, and hypertension were significantly higher in the male group than in the female group. Meanwhile, the presence of thenar muscle atrophy was significantly higher in the female group than in the male group. CONCLUSIONS: Women are more likely to experience carpal tunnel syndrome even though they have no comorbidities. We suggest that carpal tunnel syndrome especially in male patients may be reduced by early intervention for diabetes mellitus. Prospective studies are needed to validate the causal relationship between diabetes mellitus and carpal tunnel syndrome.

Usefulness of CT-based measurement of volar prominence for evaluation of risk of flexor tendon injury following fixation of a distal radius fracture.

BACKGROUND: Although some radiographic evaluations of the risk of flexor tendon injury following fixation of a distal radius fracture are useful, these radiographic measurements are limited because of their inability to obtain three-dimensional measurements. We hypothesized that CT-based measurements would be more sensitive indicators for risk estimation than radiography. METHODS: We retrospectively evaluated the relationship between plate positioning and the incidence of flexor tendon symptoms based on postoperative radiographic and CT-based measurements in 99 hands that were followed up for more than 12 months. We also compared the reproducibility, diagnostic accuracy, and ability to detect the plate-bone gap between radiographic and CT-based measurements. We also assessed the correlation between the volar prominence and plate-bone gap using CT. Multivariable analysis using stepwise logistic regression was performed to identify factors independently associated with tendon rupture or irritation. RESULTS: In single variable analysis, we found that the volar tilt was significantly smaller and the radiographic plate-to-critical line distance (PCL), CT-PCL, and CT-gap were significantly greater in the group with tendon irritation or rupture. Multivariable logistic regression analysis indicated that the CT-based measurement of the volar prominence is a significantly positive independent predictor of tendon rupture or irritation. CONCLUSION: CT-based measurement of the volar prominence may be one of the best radiographic predictors of the risk of flexor tendon injury following fixation of a distal radius fracture regardless of the plate type and distal prominence and the extent of rotation. This measurement may assist surgeons when deciding on the need for removal of hardware to decrease the long-term risk of flexor tendon rupture.

Sonography-guided arthroscopic excision is more effective for treating volar wrist ganglion than dorsal wrist ganglion.

The purpose of this study was to compare the treatment results of sonography-guided arthroscopic excision for volar and dorsal wrist ganglions. A total of 42 patients with wrist ganglions underwent sonography-guided arthroscopic resection. Clinical outcome measures included wrist range of motion, grip strength, patient-rated questionnaire Hand20, and numerical pain rating scale. All patients were assessed for recurrence throughout the follow-up period. Ganglions were located at the dorsal wrist in 26 cases and at the volar wrist in 16 cases. The mean Hand20 and pain scores were significantly improved after sonography-guided arthroscopic resection for both volar and dorsal wrist ganglions. Recurrence was seen in six cases (23%) of dorsal wrist ganglion but no cases of volar wrist ganglion (P < .05). The use of sonography-guided arthroscopic ganglion excision is better for treating volar wrist ganglion than dorsal wrist ganglion.

Multi-center rater-blinded study of early intervention with the Hand Incubator for breast cancer-related lymphedema (the BEAT-EDEMA trial): Proposal of a research protocol.

Postoperative lymphedema is considered irreversible once it has developed, and significantly lowers the patient's quality of life. However, lymphatic function has recently been clarified, and it is possible that lymphedema can be cured if early treatment is started. This two-arm randomized clinical trial (UMIN000026124) will prospectively evaluate 24 patients with early-stage breast cancer-related lymphedema at the Nagoya University Hospital and Aichi Cancer Center Hospital. The eligibility criteria will be patients who are diagnosed with stage 0-1 breast cancer-related lymphedema, as defined by the International Society of Lymphology, within 12 weeks after breast cancer surgery. The diagnosis of lymphedema will be confirmed using a bioimpedance spectroscopy device (L-Dex®). Participants will be randomized 1:1 into the intervention and control groups. The physicians and patients will be aware of their group assignment, although treatment efficacy will be evaluated by raters who are blinded to the group assignments. The intervention group will complete grasping exercises in the Hand Incubator device for 4 weeks. The primary outcome will be the change in the affected upper limb's volume after the intervention, as measured using the water displacement method. This study may help establish a standard treatment for postoperative lymphedema.

Efficacy of a forearm band in addition to exercises compared with exercises alone for lateral epicondylitis: A multicenter, randomized, controlled trial.

BACKGROUND: A forearm band is frequently used for lateral epicondylitis worldwide. However, evidence regarding its efficacy has been insufficient. The objective of this prospective, randomized, controlled trial was to analyze the effects of a forearm band for treatment of lateral epicondylitis at 1, 3, 6, and 12 months. METHODS: Patients with lateral epicondylitis were randomly allocated into a band (n = 55) or non-band (n = 55) group. Patients in the band group were instructed to wear a forearm band for more than 6 h daily for at least 6 months. Patients in both groups were instructed to perform wrist extensor stretching exercises for 30 s, 3 times daily, for 6 months. Hand10, pain, and satisfaction scores, and proportions of positive physical examinations, including tenderness assessment, Thomsen test, and middle finger extension test, were evaluated at 1, 3, 6, and 12 months after enrollment. RESULTS: There were no significant differences between the band and non-band groups with regard to Hand10, pain, or satisfaction scores at 1, 3, 6, and 12 months. Likewise, there was no significant difference in proportions of positive physical examinations between groups at 1, 3, 6, and 12 months. CONCLUSION: The results of the current study suggest that a forearm band may have no more than a placebo effect, and do not support the use of a forearm band based on its effectiveness.

Feasibility of four-dimensional preoperative simulation for elbow debridement arthroplasty.

BACKGROUND: Recent advances in imaging modalities have enabled three-dimensional preoperative simulation. A four-dimensional preoperative simulation system would be useful for debridement arthroplasty of primary degenerative elbow osteoarthritis because it would be able to detect the impingement lesions. METHODS: We developed a four-dimensional simulation system by adding the anatomical axis to the three-dimensional computed tomography scan data of the affected arm in one position. Eleven patients with primary degenerative elbow osteoarthritis were included. A "two rings" method was used to calculate the flexion-extension axis of the elbow by converting the surface of the trochlea and capitellum into two rings. A four-dimensional simulation movie was created and showed the optimal range of motion and the impingement area requiring excision. To evaluate the reliability of the flexion-extension axis, interobserver and intraobserver reliabilities regarding the assessment of bony overlap volumes were calculated twice for each patient by two authors. Patients were treated by open or arthroscopic debridement arthroplasties. Pre- and postoperative examinations included elbow range of motion measurement, and completion of the patient-rated questionnaire Hand20, Japanese Orthopaedic Association-Japan Elbow Society Elbow Function Score, and the Mayo Elbow Performance Score. RESULTS: Measurement of the bony overlap volume showed an intraobserver intraclass correlation coefficient of 0.93 and 0.90, and an interobserver intraclass correlation coefficient of 0.94. The mean elbow flexion-extension arc significantly improved from 101° to 125°. The mean Hand20 score significantly improved from 52 to 22. The mean Japanese Orthopaedic Association-Japan Elbow Society Elbow Function Score significantly improved from 67 to 88. The mean Mayo Elbow Performance Score significantly improved from 71 to 91 at the final follow-up evaluation. CONCLUSION: We showed that four-dimensional, preoperative simulation can be generated by adding the rotation axis to the one-position, three-dimensional computed tomography image of the affected arm. This method is feasible for elbow debridement arthroplasty.

The results of volar locking plate fixation for the fragility fracture population with distal radius fracture in Japanese women.

The purpose of this study was to determine whether volar locking plate fixation for distal radius fracture benefits the fragility fracture population as much as it benefits the non-fragility fracture population. This matched case-control study was conducted based on a multi-center clinical prospective cohort. A comparison of treatment outcomes after volar locking plate fixation was made between females 55 years of age and older (fragility fracture population) and males less than 75 years of age (non-fragility fracture population) by evaluating clinical, radiological, and subjective outcomes using Hand20, a validated patient-rated disability instrument. A total of 170 patients were enrolled in this study. The two cohorts were matched in terms of AO fracture type. The fragility fracture population group and the non-fragility fracture population group each consisted of 50 patients. All objective measurements including wrist range of motion and radiological evaluations, but excluding grip strength, were not significantly different between the two groups. However, the Hand20 at 18 months after surgery was worse in the fragility fracture population group than in the non-fragility fracture population group. Carpal tunnel syndrome was the most frequently encountered complication in the fragility fracture population group, with one case (2%) in the non-fragility fracture population group and six cases (12%) in the fragility fracture population group, but the difference was not significant. In conclusion, there was a significant deficit in the improvement in disability despite favorable radiological and functional outcomes in fragility fracture population patients. Therefore, the fragility fracture population, especially middle-aged or older women, needs to be informed about prolonged disability and the higher risk of upper extremity disorders prior to surgery.

Partial necrosis of the lunate after a translunate palmar perilunate fracture dislocation.

We present an extreme rare case of traumatic partial avascular necrosis of the lunate after palmar perilunate dislocation with lunate fracture. A 32-year-old female was injured by motorcycle accident with palmar perilunate fracture dislocation and lunate fracture. Scapholunate and lunotriquetrum dislocations were reduced and fixed temporarily. The torn dorsal ligament was repaired. Considering close observation with both arthroscopy and fluoroscopy, we decided not to conduct open reduction and internal fixation for the lunate. Partial avascular necrosis of the lunate appeared gradually in follow-up.

Ulnar impaction syndrome: incidence of lunotriquetral ligament degeneration and outcome of ulnar-shortening osteotomy.

PURPOSE: We hypothesized that most patients with ulnar impaction syndrome have degenerative changes of the proximal lunotriquetral (LT) membrane and that ulnar-shortening osteotomy is an effective procedure in these patients. METHODS: We retrospectively reviewed 50 wrists of 49 patients with idiopathic ulnar impaction syndrome who underwent an arthroscopic evaluation at the time of ulnar-shortening osteotomy, and subsequently at plate removal. Based on the Geissler classification, patients were divided into group A, normal, and group B, grades I to IV. The degree of degeneration of the proximal LT membrane at first-look arthroscopy was compared with that at second-look arthroscopy. RESULTS: After ulnar-shortening osteotomy, both groups improved significantly in wrist range of motion and grip strength. According to the Mayo wrist score, 29, 18, and 3 patients showed excellent, good, and fair results, respectively. Of the 50 wrists, 25 had degenerative changes (group B) in the proximal LT membrane at the time of first-look arthroscopy. Of the 25 wrists in group B, 11 wrists improved based on the Geissler grade, 9 wrists showed no changes, and 2 wrists became worse. Clinically, patients demonstrated improvement after ulnar-shortening osteotomy regardless of the degree of degenerative LT ligament changes. CONCLUSIONS: Degenerative LT membrane changes that were seen in about half of our patients were mostly of a mild nature, and the clinical outcomes of ulnar-shortening osteotomy were acceptable. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Prostaglandin E1 alleviates neuropathic pain and neural dysfunction from entrapment neuropathy associated with diabetes mellitus.

In this report, we present the results of investigation of the effects of prostaglandin E1 (PGE1) on entrapment neuropathy using a diabetic rat. A total of 60 male Sprague-Dawley rats were used in the study. The model of tibial nerve entrapment neuropathy associated with diabetes mellitus was created by streptozotocin-induced diabetic rats reared in cages with wire grid flooring. Rats were assigned to four groups: nondiabetic (n = 15), untreated diabetic (n = 15), diabetic treated with 30 µg/kg PGE1 (n = 15), and diabetic treated with 100 µg/kg PGE1 (n = 15). Pain tests and electrophysiological tests were performed at 0, 2, and 4 weeks, and assessments of gait, histology, and mRNA expression levels were performed at 4 weeks after initiating the PGE1 administration. In the 30 and 100 µg groups, the mechanical withdrawal thresholds measured by pain tests at 4 weeks (36.2 ± 16.4 g and 31.7 ± 15.3 g, respectively) and the motor conduction velocity (24.0 ± 0.2 m/s and 24.4 ± 0.3 m/s, respectively) were significantly higher than the untreated diabetic group (all P < 0.05) and lower than the nondiabetic group (all P < 0.001). In the gait analysis, the mean intensities in the 30 and 100 µg group (128.0 ± 20.1 a.u. and 109.0 ± 27.8 a.u., respectively) were significantly higher than the untreated diabetic (P < 0.01) and were not significantly different from the nondiabetic group (P = 0.81). Fiber density (P = 0.46) and fiber diameter (P = 0.15) did not show any significant differences. PGE1 significantly decreased nerve growth factor (NGF) mRNA and increased vascular endothelial growth factor (VEGF) mRNA in the tibial nerve (both P < 0.01). In conclusion, neurological deteriorations of diabetic rats were alleviated with PGE1, which is associated with inhibition of NGF and enhancement of VEGF at the entrapment site.

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.

Mechanical advantages of a truss-structure-based fracture fixation system--a novel fracture fixation device "PinFix".

A small, light, ball-joint device called PinFix, which can instantly convert a simple percutaneous cross pin fracture fixation system into a rigid external fracture fixation system based on truss structure, was developed. The purpose of this study was to compare the mechanical load and breaking strength of this truss-structure-based fixation system to that of the conventionally used external cantilever structure-based fixation system. Three types of mechanical loading tests, axial, bending, and torsion, were performed on an artificial fractured bone treated with either three-dimensional PinFix fixation, two-dimensional PinFix fixation, or conventional external fixation. The three- and two-dimensional PinFix fixations showed significantly more stiffness than conventional fixation on all three loading tests. Finite element analysis was next performed to calculate the stress distribution of the parts in PinFix and in the conventional fixator. The applied stress to the rod and connectors of PinFix was much less than that of the conventional external fixator. These results reflected the physical characteristic of truss structure in which applied load is converted to pure tension or compression forces along the members of the PinFix. In conclusion, PinFix is a simple fracture fixation system that has a truss-structure with a high rigidity.

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.