Finger flexor rigidity in the healthy population.

The involvement of the hand flexors in trigger finger is not clear. This study aimed to examine the rigidity of the flexor tendon in the first pulley territory in the hand by using ultrasound in a healthy population, as well as to create a reference scale of rigidity for the flexor tendons to compare those values in trigger fingers. We tested 35 healthy volunteers using a linear ultrasound transducer and the color Doppler method. Rigidity levels below the first pulley were examined and compared between the different fingers of the hand and the relationship between rigidity and sex and the three different age groups was evaluated. In the healthy population, the rigidity of the flexor tendons of the hand in the territory of the first pulley varied between 233.1 and 962.8 kPa, with an average of 486.42 kPa and standard deviation of 114.85. We showed that the flexors in the dominant hand were more rigid, there was a difference between the rigidity of the flexor tendons of the thumb and the other fingers of the same hand, and the ring finger of the dominant hand had stiffer flexor tendons than the fingers of the other hand in the male population. We created a value scale for the rigidity of the flexor tendons of the fingers. This base scale can be compared between different pathologies, including trigger finger. The study and all experimental protocols were approved by the local ethical committee.

Cardiac Amyloidosis Screening at Trigger Finger Release Surgery.

Cardiac amyloidosis is often preceded by orthopedic manifestations such as carpal tunnel syndrome, and 10% of patients who underwent idiopathic carpal tunnel release surgery will have biopsy-confirmed amyloid deposits in the tenosynovial sheath. Trigger finger is also commonly reported in patients with amyloidosis and involves the same tendon sheath as carpal tunnel syndrome, but the prevalence of amyloid deposition is unclear. This prospective cross-sectional study enrolled 100 patients aged ≥50 years at the time of surgery for idiopathic trigger finger. Patients underwent release surgery, and a sample of the tenosynovium of the affected finger was excised, stained with Congo red, and subtyped with mass spectrometry if amyloid was demonstrated. Further cardiac evaluation was performed in patients with amyloid deposition. Of the 100 patients (mean age 65.5 ± 8.1 years) enrolled, only 2 demonstrated amyloid deposits on Congo red staining. One patient with previous proteinuric kidney disease had fibrinogen A α-chain amyloidosis, and the other patient had untyped amyloidosis. Neither patient had cardiac involvement. A total of 13 of the 100 patients underwent concomitant carpal tunnel release surgery, and 2 of these patients had amyloid deposits in the carpal tunnel with "false-negative" samples from the trigger finger tenosynovium. In conclusion, biopsy during trigger finger release surgery demonstrated a 2% yield for amyloidosis, which is significantly lower than the previously published yield of 10% during carpal tunnel release surgery. This observation has important implications for the development of diagnostic algorithms to screen patients for amyloidosis during orthopedic operations.

Pediatric Trigger Thumb with Metacarpophalangeal Joint Hyperextension or Instability.

BACKGROUND The aim of this study was to provide the first on report on the mechanism and the different treatment measures of metacarpophalangeal joint hyperextension (MCPH) or metacarpophalangeal joint instability (MCPI) in cases of pediatric trigger thumb. Some pediatric trigger thumb patients have disease combined with excessive extension of metacarpophalangeal (MCP) joint or instability of MCP joint. MATERIAL AND METHODS A total of 1083 children with trigger thumb surgery were divided into 2 groups (the MCPH group and the MCPI group) by the extension degree of the MCP joint. After tendon sheath released, the MCPH group was treated by a cast and the MCPI group was treated by a cast and a brace. We compared the differences in baseline data and the further functional activities of interphalangeal (IP) and MCP joint between the 2 groups. RESULTS Among the 1083 cases, 154 cases (185 thumbs) were trigger thumb with MCPH or MCPI, of which 167 thumbs were placed in the MCPH group and 18 thumbs were placed in the MCPI group. The average age of the MCPH group was 2.8 years, with an average duration of disease of 13 months. The average age of the MCPI group was 6.6 years, with an average duration of disease of 33 months. MCPH still existed after cast removal. In the MCPI group, 12 out of 18 thumbs recovered; 6 thumbs relapsed at 2-4 months after brace removal. CONCLUSIONS Trigger thumb with MCPH and MCPI in children is significantly associated with multi-joint laxity. While there was still MCPH after cast treatment, there was no need for further treatment during the short-term follow-up. Cast and brace treatment after surgery was a simple, easy method for treatment of MCPI and had a good effect.

Risk factors for carpal tunnel syndrome or trigger finger following distal radius fracture: a nationwide study.

New-onset carpal tunnel syndrome (CTS) and trigger finger after distal radius fractures (DRFs) with or without open reduction and internal fixation (ORIF) have been reported inconsistently across different studies. This study assessed the incidence of CTS and trigger finger after DRFs using Taiwan National Health Insurance Research Database. In total, 1454 patients in the case (ORIF) cohort and 1454 patients in the control (non-ORIF) cohort were included in this retrospective study. The mean age was approximately 55 years old, and the female to male ratio was approximately 3/2. Nine patients underwent carpal tunnel release (CTR) surgery after diagnosis of CTS in the case group, and no patients did in the control group; whereas 19 cases of CTS were diagnosed without CTR in the case group, and 4 such cases were observed in the control group. Five cases of trigger finger were diagnosed in the case group, and 3 cases were diagnosed in the control group. CTS were significantly associated with ORIF for DRFs within 9 months after the fracture, whereas trigger finger was not significantly different between groups. Diabetes mellitus was a significant risk factor for CTS and trigger finger within 9 months after the incidence of DRFs.

Identification of the location of the A1 pulley combining palpation technique with palm landmarks and percutaneous release of A1 pulley with a 19-gauge needle: A cadaveric study.

The aims of this study were to identify the location of the A1 pulley combining palpation technique with superficial palm landmarks and to determine the efficacy and safety of A1 pulley percutaneous release with a 19-gauge needle. Fourteen fresh frozen cadaveric specimens were used: 56 fingers and 14 thumbs. The location of the A1 pulley was based on anatomical landmarks and was identified in all digits. Complete release of the A1 pulley occurred in 60 of the 70 digits (85.7%). The length of the A1 pulley in thumbs was 5.7 mm and in other fingers 4.5 mm. There were no signs of neurovascular bundle injuries. The mean distance between needle pathway and neurovascular bundle was 4.3 mm in the thumbs and 6.5 mm in the other fingers. There were no total flexor tendon injuries. The location of the A1 pulley can be predicted with success. Percutaneous release of the A1 pulley with a 19-gauge needle shows acceptable results in both safety and efficacy.

Three-dimensional printing of a microneedle array on personalized curved surfaces for dual-pronged treatment of trigger finger.

The hand function of patients who suffer from trigger finger can be impaired by the use of traditional splints. There is also a risk of systemic side effects with oral non-steroidal anti-inflammatory drugs (NSAIDs) used for pain relief. Microneedle-assisted transdermal drug delivery offers an attractive alternative for local delivery of NSAIDs. However, traditional microneedle arrays fabricated on flat surfaces are unable to deliver drugs effectively across the undulating skin surface of affected finger(s). In this study, using 3D printing, a dual-function microneedle array has been fabricated on personalized curved surfaces (microneedle splint) for drug delivery and splinting of the affected finger. The novel microneedle splint was assessed for its physical characteristics and the microneedles were shown to withstand up to twice the average thumb force without fracturing. An average skin penetration efficiency of 64% on dermatomed human cadaver skin was achieved and the final microneedle splint showed biocompatibility with human dermal cell lines. A significantly higher amount of diclofenac permeated through the skin by 0.5 h with the use of the microneedle splint as compared to intact skin. The fabricated microneedle splint can thus be a potential new approach to treat trigger finger via personalized splinting without affecting normal hand function.

MR imaging findings of trigger thumb.

Trigger finger (or trigger thumb), also known as sclerosing tenosynovitis, is a common clinical diagnosis that rarely presents for imaging. Because of this selection bias, many radiologists may not be familiar with the process. Furthermore, patients who do present for imaging frequently have misleading examination indications. To our knowledge, magnetic resonance (MR) imaging findings of trigger thumb have not been previously reported in the literature. In this article, we review the entity of trigger thumb, the anatomy involved, and associated imaging findings, which include flexor pollicis longus tendinosis with a distinct nodule, A1 pulley thickening, and tenosynovitis. In addition, in some cases, an abnormal Av pulley is apparent. In the rare cases of trigger finger that present for MR imaging, accurate diagnosis by the radiologist can allow initiation of treatment and avoid further unnecessary workup.

Clinical and pathological correlates of severity classifications in trigger fingers based on computer-aided image analysis.

BACKGROUND: The treatment of trigger finger so far has heavily relied on clinicians' evaluations for the severity of patients' symptoms and the functionality of affected fingers. However, there is still a lack of pathological evidence supporting the criteria of clinical evaluations. This study's aim was to correlate clinical classification and pathological changes for trigger finger based on the tissue abnormality observed from microscopic images. METHODS: Tissue samples were acquired, and microscopic images were randomly selected and then graded by three pathologists and two physicians, respectively. Moreover, the acquired images were automatically analyzed to derive two quantitative parameters, the size ratio of the abnormal tissue region and the number ratio of the abnormal nuclei, which can reflect tissue abnormality caused by trigger finger. A self-developed image analysis system was used to avoid human subjectivity during the quantification process. Finally, correlations between the quantitative image parameters, pathological grading, and clinical severity classification were assessed. RESULTS: One-way ANOVA tests revealed significant correlations between the image quantification and pathological grading as well as between the image quantification and clinical severity classification. The Cohen's kappa coefficient test also depicted good consistency between pathological grading and clinical severity classification. CONCLUSIONS: The criteria of clinical classification were found to be highly associated with the pathological changes of affected tissues. The correlations serve as explicit evidence supporting clinicians in making a treatment strategy of trigger finger. In addition, our proposed computer-aided image analysis system was considered to be a promising and objective approach to determining trigger finger severity at the microscopic level.

Histopathology of tenosynovium in trigger fingers.

Stenosing flexor tenosynovitis, trigger finger, is a common clinical disorder causing painful locking or contracture of the involved digits, and most instances are idiopathic. This problem is generally caused by a size mismatch between the swollen flexor tendon and the thickened first annular pulley. Although hypertrophic pulleys have been histologically and ultrasonographically detected, little is known about the histopathology of the tenosynovium covering the tendons of trigger fingers. We identified chondrocytoid cells that produced hyaluronic acid in 23 (61%) fingers and hypocellular collagen matrix in 32 (84%) fingers around the tenosynovium among 38 specimens of tenosynovium from patients with trigger fingers. These chondrocytoid cells expressed the synovial B cell marker CD44, but not the chondrocyte marker S-100 protein. The incidence of these findings was much higher than that of conventional findings of synovitis, such as inflammatory infiltrate (37%), increased vascularity (37%), hyperplasia of synovial lining cells (21%), or fibrin exudation (5%). We discovered the following distinctive histopathological features of trigger finger: hyaluronic acid-producing chondrocytoid cells originated from fibroblastic synovial B cells, and a hypocellular collagen matrix surrounding the tenosynovium. Thus, an edematous extracellular matrix with active hyaluronic acid synthesis might increase pressure under the pulley and contribute to the progression of stenosis.

Percutaneous release of trigger fingers.

Open surgery has been indicated as the surgical treatment for trigger finger for many years; however, minimally invasive techniques are replacing conventional methods. Minimally invasive techniques enable early recovery of the patient with minimal damage to soft tissues. The authors' study showed that levels of effectiveness of open surgical and percutaneous methods were superior to those of the conservative method using corticosteroid based on the cure and reappearance rates of the trigger. Percutaneous pulley release for treating trigger finger is a safe, effective, and minimally invasive surgical alternative.

Risk factors for return with a second trigger digit.

The purpose of this study was to determine predictors of return to the same practice with a second idiopathic trigger digit. A total of 2234 patients with Quinnell grade 2 or greater (objective triggering) of one or more digits were retrospectively analysed. A total of 490 of 2234 (22%) patients returned to the same practice with a second trigger digit, with an average follow-up time of 2.1 years (range, 7 days to 10 years). Predictors of return with a second trigger digit included carpal tunnel syndrome, Type 1 diabetes mellitus and duration of follow-up in years. Patients diagnosed with idiopathic trigger digit can be advised that about one in five will return to the same practice with another trigger digit, with approximately double the risk in patients that have carpal tunnel syndrome or Type 1 diabetes.

Computer aided quantification of pathological features for flexor tendon pulleys on microscopic images.

Quantifying the pathological features of flexor tendon pulleys is essential for grading the trigger finger since it provides clinicians with objective evidence derived from microscopic images. Although manual grading is time consuming and dependent on the observer experience, there is a lack of image processing methods for automatically extracting pulley pathological features. In this paper, we design and develop a color-based image segmentation system to extract the color and shape features from pulley microscopic images. Two parameters which are the size ratio of abnormal tissue regions and the number ratio of abnormal nuclei are estimated as the pathological progression indices. The automatic quantification results show clear discrimination among different levels of diseased pulley specimens which are prone to misjudgments for human visual inspection. The proposed system provides a reliable and automatic way to obtain pathological parameters instead of manual evaluation which is with intra- and interoperator variability. Experiments with 290 microscopic images from 29 pulley specimens show good correspondence with pathologist expectations. Hence, the proposed system has great potential for assisting clinical experts in routine histopathological examinations.

Epidemiology of carpal tunnel syndrome in patients with single versus multiple trigger digits.

PURPOSE: Previous studies have identified the association between trigger digit and carpal tunnel syndrome (CTS). However, whether the presence of multiple trigger digits affects the prevalence of CTS is unknown. The purpose of this study was to determine the incidence of carpal tunnel symptoms in patients treated for single versus multiple trigger digits. METHODS: We performed a retrospective review of 300 patients treated for trigger digit by injection or surgical release and recorded CTS symptoms, signs, and treatment for either the ipsilateral or contralateral hand documented within 24 months before trigger digit treatment and for an average of 35 months (range, 7- 66 mo) after treatment. Patients were categorized as having single (n = 160) or multiple (n = 140) trigger digits. Binary logistic regression modeled risk factors for development of CTS. Patient age, sex, number of trigger digits (single or multiple), and presence of diabetes, gout, thyroid disease, or thumb osteoarthritis were considered independent variables. RESULTS: A total of 58 of 140 patients (41%) who presented with multiple trigger digits exhibited concomitant carpal tunnel symptoms, compared with 26 of 160 (16%) patients who presented with a single trigger digit. Significant independent predictors of CTS associated with trigger digits in the final regression model included multiple trigger digits (odds ratio = 3.6; subjects with multiple trigger digits had significantly higher odds of carpal tunnel presentation than subjects with a single trigger digit) and diabetes (odds ratio = 1.9; diabetic subjects had significantly higher odds of carpal tunnel presentation than nondiabetics). CONCLUSIONS: A greater than 3-fold increase in the relative risk of CTS development exists in patients undergoing treatment for multiple trigger digits, compared with those undergoing treatment for a single trigger digit. Awareness of this association may aid in the early diagnosis and treatment of CTS in patients presenting with multiple trigger digits. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic III.

Resection of the flexor digitorum superficialis for trigger finger with proximal interphalangeal joint positional contracture.

PURPOSE: Open release of the A1 pulley is a widely known procedure for the treatment of trigger finger. A subset of patients presents with both trigger finger and a positional contracture of the proximal interphalangeal (PIP) joint. These patients usually have a long history of trigger finger or have already undergone a surgical release of the annular pulley. This study is a retrospective review of the outcomes of resection of the flexor digitorum superficialis (FDS) for patients whose trigger finger was associated with a positional contracture of the PIP joint. METHODS: Thirty-six patients (39 fingers) were treated by resection of the FDS after section of the A1 pulley. The mean age of the patients was 63 years (range, 45-90 y). Seven patients (19 %) had previously undergone an open release of the A1 pulley and had developed a positional contracture of the PIP joint 2 to 5 months afterward. We performed a retrospective review with a mean follow-up of 30 months (range, 12-60 mo). No patient was lost to follow-up. The active range of motion was recorded at the PIP joint before and after surgery. RESULTS: The mean preoperative positional contracture of the PIP joint was 24° (range, 15°-30°). The mean postoperative positional contracture of the PIP joint was 4° (range, 0°-10°). The most commonly affected digit was the middle finger (26 fingers, 67%). In 28 fingers (72%), full extension was achieved following only the surgical procedure. The remaining 11 fingers (28%) had a postoperative residual positional contracture (range, 5°-10°). However, all fingers achieved a full range of motion after physical therapy and an injection of betamethasone. All of the resected tendons had histological damage. CONCLUSIONS: This technique is a useful treatment for selected patients whose trigger finger is associated with a positional contracture.

Pediatric trigger thumb with locked interphalangeal joint: can observation or splinting be a treatment option?

BACKGROUND: The purpose of this study is to report the natural history of pediatric trigger thumb with locked interphalangeal joint, the efficacy of a splint for this condition, and the outcome of late surgery. METHODS: Medical records of 64 patients were retrospectively reviewed. Patients were treated with a coil splint when parents and patients accepted; otherwise, regular observation was conducted. Splint application and/or observation were terminated either when the patient gained full range of active motion without snapping, or underwent surgical intervention. RESULTS: In splint group, 92% of the patients experienced complete symptom relief in 22 months, whereas 60% resolved completely in 59 months in observation group. The differences were statistically significant. One thumb in a patient with bilateral involvement remained locked while the other completely resolved. The rest of the patients also showed improved symptom from locking to snapping. Four patients with residual snapping underwent surgery at the age of 8 years and above without any deformity and complication. CONCLUSIONS: Splint was efficient in shortening the time for symptom relief; however, the natural history revealed the self-limiting nature of this condition. Late surgery was safe and effective for residual snapping and can be presented as one treatment option to the patients and families, combined with conservative treatment. LEVEL OF EVIDENCE: Level III--retrospective comparative study.

Long arm casting for treatment of trigger finger in children: report of three cases.

Trigger digit in children is rare. Triggering predominantly occurs in thumbs presenting a flexion deformity of interphalangeal joint of finger. In children, the disease usually presents with a remained finger in locked flexion, unlike the adults in whom triggering is more prevalent. The pathology of the disease includes locking of the tendon over A1 pulley. Some treatment modalities have been suggested to cure the trigger thumb, such as conservative therapy without any invasive approach, and surgery. To the best of our knowledge, there is no report about casting as a treatment method for trigger finger in children. Herein, we report three cases of patients with trigger finger, who were treated by using long arm casting.

Congenital trigger thumb in children: electron microscopy and immunohistochemical analysis of the first annular pulley.

Although numerous studies have been performed on congenital trigger thumb (CTT), the pathogenesis is still unknown. Cytocontractile proteins and myofibroblasts are present during soft-tissue contraction, and they may have a role in CTT. The aim of the study is to clarify the immunohistochemical and the electron microscopy characteristics of the first annular (A-1) pulley in CTT. The specimens from the A-1 pulleys were collected from 22 children with CTT. Electron microscopy was used to study the last five specimens. Immunohistochemistry staining demonstrated that all specimens stained positively for vimentin and for α-smooth muscle actin, and stained negatively for desmin. Electron microscopy showed fibroblasts in collagenous matrix, which contain vimentin-like material and associated at the surface with elastin-like tubular matrix filaments and elastin fibers. In two specimens, a few cells showed markers of myofibroblastic differentiation. The presence of the cytocontractile proteins and myofibroblasts suggests proliferation of fibrous tissues during either the intrauterine or extrauterine phase of development and may account for the presence of congenital stenosis at the level of the A-1 pulley. We believe that CTT may be developmental; if the process started in the intrauterine phase it might present as a fixed flexion contracture and will show mature fibroblasts. If the process started in the extrauterine phase, it might present as triggering first and will show myofibroblastic changes, then with the maturation of the fibrous tissue, result in a fixed flexion contracture.