Sonographic appearance of trigger fingers

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.

Retrograde Percutaneous Release of Trigger Finger or Thumb Using Sono-Instruments®: Detailed Technique, Pearls, and Pitfalls

Percutaneous release is a common treatment option for trigger finger stenosing tenosynovitis. While surgical and conservative treatments are available, percutaneous techniques offer several advantages, including faster recovery time, reduced complications, and simultaneous treatment of multiple trigger fingers. The sono-instrument is a minimally invasive device designed for surgical release of the A1 pulley in adults. The device is efficient and safe, and in addition, several design features enhance the visibility of the instrument under ultrasound imaging. The technique is truly percutaneous, as the whole operation is done through a single needle puncture. This minimizes postoperative discomfort and allows an immediate return to daily living and professional activities. The technique can be performed in an outpatient clinic under local anesthesia. The learning curve is quick; however, surgeons must acquire experience in hand sonography to master this new form of surgery. The aim of this article is to provide an in-depth exposition of the technical nuances, pearls, and pitfalls of this novel retrograde percutaneous release method. To our knowledge, this is the first retrograde truly percutaneous release technique yet described, facilitated by the novel Sono-Instruments®.

Diagnostic and Interventional US of the Wrist and Hand: Quadrant-based Approach

Diagnostic and interventional US of the wrist and hand can be challenging due to the small size and superficial location of structures and various disorders that need to be considered. A quadrant-based approach (volar, ulnar, dorsal, and radial) provides a rational method for performing a focused examination and joint positioning during both diagnostic imaging and intervention. Volar wrist disorders primarily involve the median nerve and the digital flexor system comprised of the flexor tendons and pulleys. The ulnar nerve and extensor carpi ulnaris tendon are chiefly responsible for ulnar-sided wrist pain. The differential diagnosis for dorsal-sided symptoms typically involves the extensor tendon compartments and includes distal intersection syndrome, extensor pollicis longus tear, and digital extensor apparatus injury. The soft-tissue ganglion is the most common abnormality in the dorsal wrist, typically associated with wrist ligaments or joint capsule. Radial-sided pain may be secondary to de Quervain tenosynovitis and must be differentiated from the more proximal intersection syndrome. US is an important tool for assessing the ulnar collateral ligament of the first metacarpophalangeal joint of the thumb and differentiating between displaced and nondisplaced tears, thereby influencing management. Despite the complexity of the anatomy and potential pathologic features within the wrist, a focused quadrant-based examination can permit the sonologist to focus on the structures of relevance. In conjunction with a systematic approach, this can aid in precise and efficient diagnostic scanning and intervention of the wrist and hand. ©RSNA, 2023 Supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center.

Patient Experiences after Open Trigger Finger Release in Patients with Type 1 and Type 2 Diabetes-A Retrospective Study Using Patient-reported Outcome Measures

Trigger finger is overrepresented among patients with diabetes mellitus (DM). Whether DM affects the outcome after open trigger finger release (OTFR) in patients with DM is not known. Our aim was thus to explore outcomes after OTFR in patients with type 1 (T1D) and type 2 DM (T2D).

Methods

Data included patient-reported outcome measures (PROMs) from all OTFRs performed between 2010 and 2020 registered in the Swedish national registry for hand surgery in individuals over 18 years cross-linked with the Swedish National Diabetes Register (NDR). PROMs included QuickDASH and HQ8, a questionnaire designed for national registry for hand surgery, preoperative and at 3 and 12 months postoperative. HQ8 included pain on load, pain on motion without load, and stiffness. Outcome was calculated using linear-mixed models and presented as means adjusted for age and stratified by sex.

Results

In total, 6242 OTFRs were included, whereof 496 had T1D (332, 67% women) and 869 had T2D (451, 52% women). Women with T1D reported more symptoms of stiffness (P < 0.001), and women with T2D reported more pain on load (P < 0.05), motion without load (P < 0.01), and worse overall result at 3 months. At 12 months, however, no differences were found in any of the HQ-8 PROMs among men or women. Women with T2D had slightly higher QuickDASH scores at 3 and 12 months.

Conclusion

Patients with T1D and T2D can expect the same results after OTFR as individuals without DM, although the improvement might take longer especially among women with T2D.

The cross-sectional area ratio of a specific part of the flexor pollicis longus tendon- a stable sonographic measurement for trigger thumb: a cross-sectional trial

BACKGROUND

Trigger thumb is a pathologic condition of the digital pulleys and flexor tendons. To find a cutoff value of the cross-sectional area ratio of specific parts of the flexor pollicis longus tendon to diagnosis trigger thumb in the high-frequency ultrasound examination.

METHODS

We evaluated 271 healthy volunteers and 57 patients with clinical diagnosis of trigger thumb. The cross-sectional area of the metacarpophalangeal joint of flexor pollicis longus tendon (C1) and the cross-sectional area of the midpoint of the first metacarpal of flexor pollicis longus tendon (C2) were analyzed.

RESULTS

There is no difference between gender, age and left and right hands in the ratio of C1 to C2 (C1/ C2). The mean of C1/ C2 in the healthy thumb was 0.983 ± 0.103, which was significantly smaller in comparison to the diseased thumb (P < 0.05). Based on the receiver operating characteristic curve, we chose the diagnostic cut-off value for the C1/ C2 to be 1.362 and 1.153 in order to differ a trigger thumb from children and adults.

CONCLUSIONS

The C1/ C2 of the healthy thumb was relatively stable, with a mean value of 0.983 ± 0.103. The cutoff value of C1/C2 to distinguish healthy thumb from diseased thumb in children and adults were 1.362 and 1.153, respectively.

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.

Treatment of Trigger finger by ultrasound-guided needle release of a1 pulley: A series of 105 cases

INTRODUCTION

We aimed to evaluate the efficacy and tolerance of A1 pulley release using the needle technique, under ultrasound guidance, in patients with symptomatic trigger finger.

METHODS

All patients with symptomatic trigger finger underwent A1 pulley release using an intramuscular 21 gauge (G) needle. Quinnell grade (I-IV), Quick Disabilities of Arm, Shoulder & Hand (QuickDASH) score (0-100) and pain score on a visual analog scale (VAS: 0-10mm) were recorded at inclusion. The primary endpoint was complete resolution of the trigger finger at 6 months.

RESULTS

Eighty-four patients totaling 105 treated digits were included. Mean age was 63.3±10.7 years. Prior to treatment, mean VAS pain score was 5.8±2.6mm, and mean QuickDASH score was 44.3±19.1. At 6 months, disappearance of symptoms was achieved in 85 of 91 digits with follow-up (93.4%), and in 85.7% at 12 months. The absolute reduction in VAS pain and QuickDASH scores at 6 months was respectively 4.1±3.1 (P<0.001) and 36.1±20.7 (P<0.001), and 90% of patients reported being satisfied or very satisfied at 6 months. Long duration of symptoms was significantly associated with persistent trigger finger at 6 months after intervention. Complications were rare and minor. Tenosynovitis occurred in 5.7% of cases, for which a corticosteroid injection into the tendon sheath rapidly led to favorable resolution.

CONCLUSION

Treatment of trigger finger by release of the A1 pulley under ultrasound guidance using the needle technique is a mildly invasive technique that yields rapid and effective symptom resolution with good tolerance up to 12 months.

High HbA1c Levels Are Associated With Development of Trigger Finger in Type 1 and Type 2 Diabetes: An Observational Register-Based Study From Sweden

OBJECTIVE

Trigger finger (TF) is a hand disorder causing the fingers to painfully lock in flexion. Diabetes is a known risk factor; however, whether strict glycemic control effectively lowers risk of TF is unknown. Our aim was to examine whether high HbA1c was associated with increased risk of TF among individuals with diabetes.

RESEARCH DESIGN AND METHODS

The Swedish National Diabetes Register (NDR) was cross-linked with the health care register of the Region of Skåne in southern Sweden. In total, 9,682 individuals with type 1 diabetes (T1D) and 85,755 individuals with type 2 diabetes (T2D) aged ≥18 years were included from 2004 to 2019. Associations between HbA1c and TF were calculated with sex-stratified, multivariate logistic regression models with 95% CIs, with adjustment for age, duration of diabetes, BMI, and systolic blood pressure.

RESULTS

In total, 486 women and 271 men with T1D and 1,143 women and 1,009 men with T2D were diagnosed with TF. Increased levels of HbA1c were associated with TF among individuals with T1D (women OR 1.26 [95% CI 1.1-1.4], P = 0.001, and men 1.4 [1.2-1.7], P < 0.001) and T2D (women 1.14 [95% CI 1.2-1.2], P < 0.001, and men 1.12 [95% CI 1.0-1.2], P = 0.003).

CONCLUSIONS

Hyperglycemia increases the risk of developing TF among individuals with T1D and T2D. Optimal treatment of diabetes seems to be of importance for prevention of diabetic hand complications such as TF.

Ultrasound-guided needle release of A1 pulley combined with corticosteroid injection is more effective than ultrasound-guided needle release alone in the treatment of trigger finger

BACKGROUND

The purpose of the present study was to evaluate the clinical effectiveness of ultrasonography-guided needle release of A1 pulley combined with corticosteroid injection by comparing it with ultrasound-guided needle release of the A1 pulley alone.

METHODS

A total of 49 patients (55 fingers, thumb) with trigger fingers were included in this retrospective study. Twenty-seven fingers were treated with ultrasound-guided needle release of the A1 pulley alone (monotherapy group), and 28 fingers were treated with needle release of the A1 pulley combined with corticosteroid injection (combination group). Visual analog scale (VAS), Froimson scale, postoperative recurrence rate, and thickness of A1 pulley at baseline, Week-2, Week-12, and Month-6 were recorded.

RESULTS

Higher clinical cure rates were observed in the combination group at Week-2 after treatment among patients with the Froimson scale Grade III and IV (p < 0.05). Among Froimson scale Grade IV patients, the combination group had a significantly thinner thickness of A1 pulley and better articular pain relief at Week-2 (all p < 0.05). No significant differences were found in the clinical cure rate, the thickness of the A1 pulley, articular pain relief, and recurrence rate between the two groups at Week-12 and Month-6 (all p > 0.05).

CONCLUSIONS

Ultrasonography-guided needle release of A1 pulley plus corticosteroid injection was superior to ultrasonography-guided A1 pulley needle release alone during early-stage treatment of severe patients with trigger fingers. Moreover, ultrasonography-guided A1 pulley needle release combined with corticosteroid injection narrows the thickness of the A1 pulley. It is necessary to carry out preoperative evaluation and individualized treatment for patients of various severities.

EURO-MUSCULUS/USPRM Dynamic Ultrasound Protocols for Wrist and Hand

ABSTRACT

In this dynamic protocol, ultrasound evaluation of the wrist and hand is described using various maneuvers for relevant conditions. Scanning videos are coupled with real-time patient examination videos. The authors believe that this practical guide - prepared by the international consensus of several experts - will help musculoskeletal physicians perform a better and uniform/standard examination approach.

Ultrasound-Guided Percutaneous A1 Pulley Release by Acupotomy (Needle-Knife): A Cadaveric Study of Safety and Efficacy

Purpose

This study was to assess the safety and effectiveness of ultrasound-guided percutaneous A1 pulley release by acupotomy on unembalmed cadavers.

Materials and Methods

Sixty digits (from six cadavers, three male and three female) were split into two groups using stratified randomization. All procedures were completed by a single doctor with rich experience in ultrasound-guided treatment. In the acupotomy group, the A1 pulley was released under ultrasound-guided by a needle-knife; while in the needle group, the A1 pulley was released under ultrasound-guided by a 21-gauge needle. Two groups completed six thumbs and 24 fingers, respectively. Another anatomist, blinded to the two techniques, assessed the safety, including the minimum distance between the incision and the neurovascular; flexor tendon, neurovascular and A2 pulley injury or not. Completeness release of the A1 pulley was recorded as effectiveness.

Results

No neurovascular or A2 pulley injuries were recorded. However, the incision of the thumb in both groups biased to the radial side (P <0.05), while the incision of the finger biased to the ulnar side (P <0.05). No significant flexor tendon injury was found, and only five cases (16.7%) had minor scratches in the acupotomy group; while in the needle group, 15 cases had minor scratches and lacerations occurred in three cases. The flexor tendon injury rate was 60%. Compared with the needle, ultrasound-guided acupotomy release is safer (P <0.05). The ultrasound-guided acupotomy technique was significantly more likely to result in a complete A1 pulley release compared to the needle technique (28 of 30 [93.3%] versus 11 of 30 [36.7%]; P <0.05).

Conclusion

Ultrasound-guided percutaneous A1 pulley release by acupotomy is a safe and effective technique. When releasing the thumb by ultrasound-guided, be careful not to bias to the radial side to avoid neurovascular injury, while when releasing a finger, be careful not to bias to the ulnar side.

Very low prevalence of ultrasound-detected tenosynovial abnormalities in healthy subjects throughout the age range: OMERACT ultrasound minimal disease study

Objectives

This study aimed to determine the prevalence of ultrasound-detected tendon abnormalities in healthy subjects (HS) across the age range.

Methods

Adult HS (age 18–80 years) were recruited in 23 international Outcome Measures in Rheumatology ultrasound centres and were clinically assessed to exclude inflammatory diseases or overt osteoarthritis before undergoing a bilateral ultrasound examination of digit flexors (DFs) 1–5 and extensor carpi ulnaris (ECU) tendons to detect the presence of tenosynovial hypertrophy (TSH), tenosynovial power Doppler (TPD) and tenosynovial effusion (TEF), usually considered ultrasound signs of inflammatory diseases. A comparison cohort of patients with rheumatoid arthritis (RA) was taken from the Birmingham Early Arthritis early arthritis inception cohort.

Results

939 HS and 144 patients with RA were included. The majority of HS (85%) had grade 0 for TSH, TPD and TEF in all DF and ECU tendons examined. There was a statistically significant difference in the proportion of TSH and TPD involvement between HS and subjects with RA (HS vs RA p<0.001). In HS, there was no difference in the presence of ultrasound abnormalities between age groups.

Conclusions

Ultrasound-detected TSH and TPD abnormalities are rare in HS and can be regarded as markers of active inflammatory disease, especially in newly presenting RA.

Thumb ultrasound: Technique and pathologies

Ultrasound is ideally suited for the assessment of complex anatomy and pathologies of the thumb. Focused and dynamic thumb ultrasound can provide a rapid real-time diagnosis and can be used for guided treatment in certain clinical situations. We present a simplified approach to scanning technique for thumb-related pathologies and illustrate a spectrum of common and uncommon pathologies encountered.

Trigger Finger? Just Shoot!

Trigger finger is a common condition usually curable by a safe, simple corticosteroid injection. Trigger finger results from a stenotic A1 pulley that has lost its gliding surface producing friction and nodular change in the tendon. This results in pain and tenderness to palpation of the A1 pulley, progressing to catching and then locking. Splinting for 6 to 9 weeks produces gradual improvement in most patients as does a quick steroid injection with the latter resulting in resolution of pain in days and resolution of catching or locking in a few weeks. Percutaneous or open release should be reserved for injection failures particularly those at high risk for continued injection failure including diabetics and those with multiple trigger fingers. We present a step-by-step method for injection with illustrations to encourage primary care providers to offer this easily performed procedure to their patients.

Diabetes: a silent player in musculoskeletal interventional radiology response

Diabetes has an important role in the development of several musculoskeletal disorders, such as adhesive capsulitis of the shoulder (ACs) and stenosing flexor tenosynovitis of the finger (SfTf). The etiopathophysiology of ACs and SfTf in diabetic patients is associated with both chronic hyperglycemia, increased amounts of visceral adiposity and chronic inflammation. Chronic hyperglycemia stimulates the creation of cross-links between collagen molecules, impairing degradation and resulting in the build-up of excessive collagen deposits in the cartilage, ligaments, tendon sheaths and tendons. Increased adipocytes in diabetic patients secrete proteins and cytocines such as TNF-α, IL-6 and IL-13 which result in overproduction of pro-inflammatory factors, destruction of normal tissue architecture and fibrosis. Both hyperglycemia and adipocytes inhibit efferocytosis, limiting natural resolution. Recently, multiple image-guided interventional radiology musculoskeletal treatment options have been developed, such as ultrasound-guided glenohumeral capsule hydrodistension for ACs and ultrasound-guided percutaneous pulley release for trigger finger. Diabetes can negatively influence outcomes in patients with ACs and SfTf and may impact the decision of which specific procedure technique should be employed. Further studies are necessary to define how diabetes influences response to interventional radiology treatments of these disorders, as well as the extent to which control of blood sugar levels can contribute towards the personalization and optimization of patient follow up.

Power Doppler Ultrasound Assessment of A1 Pulley. A New Target of Inflammation in Psoriatic Arthritis?

Objective: To determine the prevalence of grey scale and power Doppler (PD) ultrasound (US) features of A1 pulley inflammation in a cohort of psoriatic arthritis (PsA) patients compared with rheumatoid arthritis (RA) patients.

Methods: Sixty patients (30 with PsA and 30 with RA) were consecutively enrolled. The main clinimetric indexes were recorded, and US assessment of A1 pulleys from second to fifth fingers bilaterally was carried out. The presence of A1 pulley inflammation, defined as PD signal within a thickened pulley, was registered.

Results: A1 pulley inflammation was found in 15 of 240 fingers (6.3%) of eight PsA patients (26.7%) and in one of 240 fingers (0.4%) of one RA patient (3.3%) (p < 0.01 and p = 0.03, respectively). Seven of eight PsA patients (88%) with at least one inflamed A1 pulley had a moderate/high disease activity score. The regression linear analysis (R² = 0.36, adjusted R² = 0.31) showed that A1 pulley inflammation was correlated with Disease Activity Index for Psoriatic Arthritis (DAPSA) (β = 0.43, p = 0.03).

Conclusion: US A1 pulley inflammation appears to be relatively common at patient level in PsA, seems to be a characteristic feature of PsA compared to RA, and correlates with DAPSA.

Ultrasound findings in finger flexor tendons in systemic sclerosis: A cross-sectional pilot study

OBJECTIVE

Finger flexion contractures are an important cause of disability in patients with systemic sclerosis; however, their pathophysiology is poorly understood. Our aim was to assess the feasibility of scanning finger flexor tendons in patients with systemic sclerosis and explore the ultrasound findings in these tendons, including measurement of finger flexor tendon complex.

METHODS

Grey-scale and power Doppler ultrasound assessment of the finger flexor tendon complex including tendon structure and surrounding soft tissue. Measurements of the finger flexor tendon complex (A1 pulley, tendon and palmar plate) were made. Feasibility was assessed by the number of fingers which could be measured.

RESULTS

We studied the second to fifth flexor tendons (n = 160) of both hands in 20 patients with systemic sclerosis, including early and established disease. We were able to assess the finger flexor tendon complex and make measurements of the flexor tendon and palmar plate in all (n = 40) and A1 pulley in almost all (n = 39) of the studied fingers. Common pathologies identified included peritendinous (n = 12) and soft tissue (n = 8) calcification. Tendon thickening was seen in six patients, but synovitis/tenosynovitis was rare. The A1 pulley was thickened in patients with systemic sclerosis (0.46 mm), in particular, those with diffuse cutaneous systemic sclerosis (0.50 mm).

CONCLUSION

We were able to successfully assess, including making measurements of, the finger flexor tendon complex in patients with systemic sclerosis. Our study showed calcifications in the peritendinous areas and soft tissue and thickening of the A1 pulley. These findings may play a role in the pathophysiology of systemic sclerosis-hand contractures by causing mechanical impingement of the finger flexion mechanism. This pilot study will guide future research to look for potential (treatable) causes of finger flexion contractures in patients with systemic sclerosis.

Characterization of Hand Tendons Through High-Frequency Ultrasound Elastography

Tendon stiffness plays an important role in the tendon healing process, and many studies have indicated that measuring the shear wave velocity (SWV) on tendons relates to their stiffness. Because the thickness of hand tendons is a few millimeters, high-resolution imaging is required for visualizing hand tissues. However, the resolution of current ultrasound elastography systems is insufficient. In this study, a high-frequency (HF) ultrasound elastography system is proposed for measuring the SWVs of hand tendons. The HF ultrasound elastography system uses an external vibrator to create shear waves on hand tendons. Then, it uses a 40-MHz HF ultrasound array transducer with ultrafast ultrasound imaging technology to measure the SWV for characterizing hand tendons. A handheld device that combines a transducer and a vibrator allows the user to scan hand tissues. The biases of HF ultrasound elastography were measured in gelatin phantom experiments and were less than 6% compared to standard mechanical testing approach. Human experiments showed the ability to use HF ultrasound elastography to distinguish different SWVs of hand tendons. The SWVs were 0.73 ± 0.65 m/s and 1 ± 0.54 m/s for flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP), respectively, and 0.52 ± 0.14 m/s and 4.02 ± 0.77 m/s for extensor tendon under stretch and contraction conditions, respectively. The simplicity and convenience of the HF ultrasound elastography system for measuring hand tendon stiffness make it a promising tool for evaluating the severity of hand injuries and the performance of rehabilitation after hand injuries.

Ultrasound Features of Trigger Finger: Review of the Literature

Trigger finger is a common pathologic condition of the digital pulleys and flexor tendons in the hand. The key clinical finding is a transient blockage of the digit when it is flexed with subsequent painful snapping when it is extended. Imaging is a helpful guide for establishing the severity of the disease, identifying the underlying cause, and deciding the appropriate management. This narrative review aims to recall the anatomic and pathologic bases and describe the ultrasound features of trigger finger, also including common ultrasound findings and complications after therapy. Ultrasound enables an accurate static and dynamic evaluation of trigger finger as well as a comparison with the adjacent normal digits and thus should be considered the radiologic modality of first choice for its diagnosis.

Correlation between Hypervascularization of the First Annular Pulley on Color Doppler Imaging of Trigger Finger and Patients' Backgrounds

OBJECTIVES

The aim of this study was to investigate the correlation between hypervascularization of the first annular (A1) pulley on color Doppler imaging of trigger finger and patients' backgrounds.

METHODS

A total of 148 trigger digits from 144 patients were studied with ultrasound at the time of initial diagnosis. We observed the A1 pulley at the level of the metacarpophalangeal joint in a transverse image and noted the presence or absence of a signal in the A1 pulley on color Doppler imaging. Patients' ages, sexes, clinical grades, symptom durations, prevalence of interphalangeal joint contracture, and visual analog scale pain scores were compared between the groups with positive and negative Doppler findings.

RESULTS

The 144 patients included 45 men and 99 women. Sixty-one of 148 digits (41%) showed positive Doppler findings in the A1 pulley. Patients' ages and visual analog scale scores in the Doppler-positive group were slightly greater than those in the Doppler-negative group (P = .03; P < .01, respectively). The digit with positive Doppler findings tended to be categorized into a severer grade and into the group with a shorter symptom duration (P < .01 for both).

CONCLUSIONS

Hypervascularization of the A1 pulley tended to appear in an earlier period after the patients had become aware of symptoms, as frequently as their symptoms became severe, in conjunction with higher pain scores. Doppler imaging of the A1 pulley might help in better understanding patients' conditions.

Ultrasonographic Features of Trigger Finger in Patients With Hyperuricemia

PURPOSE

The purpose of the current study was to compare demographic differences and ultrasonographic features in primary trigger finger and trigger finger in association with hyperuricemia.

METHODS

Between October 2008 and February 2010, a prospective review of consecutive cases of 54 patients with trigger finger and hyperuricemia, 76 patients with a trigger finger without hyperuricemia, and 80 control cases were enrolled. The clinical results were analyzed by descriptive epidemiology, an ultrasonographic measurement of the thickness of A1 pulley, cross-sectional area of the flexor tendon and synovium.

RESULTS

The middle finger was primarily affected, followed by the index and ring fingers in both trigger finger groups. The thickness of A1 pulley, cross-sectional area of the flexor tendon, and flexor tendon with synovium in trigger finger without hyperuricemia group were significantly larger than that in trigger finger with hyperuricemia and control groups. There was no significant difference between trigger finger with hyperuricemia and control groups. Double-contour sign and tophus were only observed in trigger finger with hyperuricemia group.

CONCLUSIONS

Thickness of A1 pulley, cross-sectional area of the flexor tendon, and flexor tendon with synovium were significantly larger in trigger finger without hyperuricemia group. These findings were not evident in trigger finger with hyperuricemia group.

Effect of metacarpophalangeal joint position on A1 pulley and flexor digitorum tendons in trigger digit

BACKGROUND

The aim of this study was to evaluate and compare the cross-sectional area (CSA) of flexor digitorum tendons and the thickness of first annular (A1) pulleys between contralateral normal digits and trigger digits (TDs) at positions of finger flexion and extension using a noninvasive ultrasound system.

METHODS

Seventeen affected fingers of 17 patients (6 men and 11 women) with TDs in one hand, and 17 contralateral normal digits without trigger finger symptoms were examined. The sonographic appearances of flexor digitorum tendons and A1 pulleys were observed at two positions of metacarpophalangeal (MCP) joint flexion: 0° and 60°.

RESULTS

The findings of this study indicate that CSA of flexor digitorum tendons and A1 pulley thickness were significantly larger in both positions of 0° and 60° flexion of MCP joint compared with contralateral normal digits (p < 0.01). In TDs, there was a significantly thicker A1 pulley at 60° flexion of MCP joint than that at 0° flexion (p < 0.01), but no significant change on CSA of flexor tendons.

CONCLUSION

Our results suggested that TDs lead to the thicker A1 pulley and larger CSA of the flexor digitorum tendons. The mismatch in volume change between CSA of flexor digitorum tendons and A1 pulley thickness during MCP flexion may lead to the trigger phenomenon.

Comprehensive simulation on morphological and mechanical properties of trigger finger - A cadaveric model

Trigger finger has long been a common disorder in hand orthopedics. To clarify the unknown causative factors regarding the disease, numerous experiments were done on human cadavers, including tendon forces, tendon moment arm, mechanical properties of the pulley, gliding resistance, etc. However, most of these studies were conducted on normal fingers. As the etiology of trigger finger is still controversial on whether it is an outcome of tendon nodule or pulley scarring, in this study, a trigger finger model was built combining both the nodule created by silicone gel injection and pulley constriction by external compression. Indentation and gliding resistance tests were performed on cadaveric specimens to verify the model. Results showed that after silicone gel injection into the tendon, a significant increase in thickness was found. In addition, no significant difference was found in the toe region compressive modulus of the tendon after injection. Moreover, maximum, drop of gliding resistance and work of extension were all found to be significantly larger as the severity of triggering increased. Our results indicated we have developed a feasible cadaver model simulating trigger finger nodule which could be utilized for further experiments to elucidate other causative factors and biomechanical features of trigger finger in the future.

Hallux saltans due to stenosing tenosynovitis of flexor hallucis longus: dynamic sonography and arthroscopic findings

Triggering of the toes is rare, with isolated cases reported in the literature involving predominantly the flexor hallucis longus (FHL) tendon, a condition known as "hallux saltans" (HS). We report the dynamic sonographic findings of a 42-year-old female with a 2-month history of ankle pain and triggering of right hallux, consistent with HS. Sonography demonstrated tenosynovitis and focal thickening of FHL at the level of hindfoot, with a fibrous band adjacent to the tendon. Dynamic ultrasound showed triggering and snapping of FHL tendon during hallux flexion and extension, respectively. We present comprehensive documentation of this rare entity, including sonographic still images and cine clips, as well as correlation with arthroscopic surgical findings.

Beyond ulcers and osteomyelitis: imaging of less common musculoskeletal complications in diabetes mellitus

Metabolic perturbations in diabetes mellitus affect various organ systems and can lead to end-organ failure. Though most musculoskeletal (MSK) complications of diabetes mellitus are usually not life-threatening, they are often the cause of significant morbidity. While some of the MSK complications have a proven association with diabetes mellitus, others have been loosely associated because of their frequent coexistence, as are the rheumatologic complications. While many of these conditions are well-known, some are overlooked in routine clinical practice. This article focuses on highlighting key imaging features of less common MSK complications and associations of diabetes mellitus.

Sonography of Non-neoplastic Disorders of the Hand and Wrist Tendons

Tendon disorders commonly cause hand and wrist disability and curtail the performance of work-related duties or routine tasks. Imaging is often needed for diagnosis, but it requires knowledge of the complex anatomic structures of the tendons of the hand and wrist as well as familiarity with related disorders. This review article aims to provide medical professionals with guidelines for the sonographic assessment of the tendons of hand and wrist and related disorders. Sonographic features of tendon disorders affecting the hand and wrist are described here, specifically: infectious tenosynovitis; tendon rupture or tearing; stenosing forms of tenosynovitis such as De Quervain disease and trigger finger; intersection syndrome; insertional tendinopathy; several forms of tendinous instability such as extensor carpi ulnaris instability, climber finger, and boxer knuckle; and tendinopathy in inflammatory rheumatic diseases. Postsurgical evaluation of the hand and wrist tendons is also discussed, including the healthy and pathologic appearances of operated tendons as well as impingement from orthopedic hardware. In conclusion, sonography is effective in assessing the tendons of the hand and wrist and related disorders and represents a valuable tool for diagnosis.

A medical imaging analysis system for trigger finger using an adaptive texture-based active shape model (ATASM) in ultrasound images

Trigger finger has become a prevalent disease that greatly affects occupational activity and daily life. Ultrasound imaging is commonly used for the clinical diagnosis of trigger finger severity. Due to image property variations, traditional methods cannot effectively segment the finger joint’s tendon structure. In this study, an adaptive texture-based active shape model method is used for segmenting the tendon and synovial sheath. Adapted weights are applied in the segmentation process to adjust the contribution of energy terms depending on image characteristics at different positions. The pathology is then determined according to the wavelet and co-occurrence texture features of the segmented tendon area. In the experiments, the segmentation results have fewer errors, with respect to the ground truth, than contours drawn by regular users. The mean values of the absolute segmentation difference of the tendon and synovial sheath are 3.14 and 4.54 pixels, respectively. The average accuracy of pathological determination is 87.14%. The segmentation results are all acceptable in data of both clear and fuzzy boundary cases in 74 images. And the symptom classifications of 42 cases are also a good reference for diagnosis according to the expert clinicians’ opinions.

Morphological alterations of the tendon and pulley on ultrasound after intrasynovial injection of betamethasone for trigger digit

Purpose

The aim of this study was to elucidate whether intrasynovial corticosteroid injections for trigger digit reduced the volume of the tendon and pulley on high-resolution ultrasonography.

Methods

Twenty-three digits of 20 patients with trigger digit were included. Each affected finger was graded clinically according to the following classification: grade I for pre-triggering, grade II for active triggering, grade III for passive triggering, and grade IV for presence of contracture. Axial ultrasound examinations were performed before an intrasynovial corticosteroid injection and at an average of 31 days after the injection. The transverse diameter, thickness, and cross-sectional area of the tendon and the thickness of the pulley were measured by two independent, blinded researchers.

Results

At least 1 grade of improvement was achieved in this study group by the time of the second examination. The transverse diameter and cross-sectional area of the tendon and the thickness of the pulley significantly decreased (P<0.05).

Conclusion

The injection of a single dose of betamethasone improved clinical symptoms by reducing the volume of both the tendon and pulley, which may be related to the fact that tendon and pulley ruptures are delayed by corticosteroid injections.

Quantitative Assessment of First Annular Pulley and Adjacent Tissues Using High-Frequency Ultrasound

Due to a lack of appropriate image resolution, most ultrasound scanners are unable to sensitively discern the pulley tissues. To extensively investigate the properties of the A1 pulley system and the surrounding tissues for assessing trigger finger, a 30 MHz ultrasound system was implemented to perform in vitro experiments using the hypodermis, A1 pulley, and superficial digital flexor tendon (SDFT) dissected from cadavers. Ultrasound signals were acquired from both the transverse and sagittal planes of each tissue sample. The quantitative ultrasonic parameters, including sound speed, attenuation coefficient, integrated backscatter (IB) and Nakagami parameter (m), were subsequently estimated to characterize the tissue properties. The results demonstrated that the acquired ultrasound images have high resolution and are able to sufficiently differentiate the variations of tissue textures. Moreover, the attenuation slope of the hypodermis is larger than those of the A1 pulley and SDFT. The IB of A1 pulley is about the same as that of the hypodermis, and is very different from SDFT. The m parameter of the A1 pulley is also very different from those of hypodermis and SDFT. This study demonstrated that high-frequency ultrasound images in conjunction with ultrasonic parameters are capable of characterizing the A1 pulley system and surrounding tissues.

Correlation Between Sonographic and In Vivo Measurement of A1 Pulleys in Trigger Fingers

The thickness of 210 A1 pulleys of 21 male and female healthy volunteers in two different age groups (20-35 y and 50-70 y) were measured by ultrasound. In a second group, the thickness of 15 diseased A1 pulleys and 15 A1 pulleys of the corresponding other hand of 10 patients with the clinical diagnosis of trigger finger were measured by ultrasound. During open trigger finger release, a strip of A1 pulley was excised and immediately measured using an electronic caliper. The average pulley thickness of healthy volunteers was 0.43-0.47 mm, compared to 0.77-0.79 mm in patients with trigger finger. Based on the receiver operating characteristic (ROC) curve, a diagnostic cut-off value of the pulley thickness at 0.62 mm was defined in order to differ a trigger finger from a healthy finger (sensitivity and specificity of 85%). The correlation between sonographic and effective intra-operative measurements of pulley thickness was linear and very strong (Pearson coefficient 0.86-0.90). In order to distinguish between healthy and diseased A1 pulleys, 0.62 mm is a simple value to use, which can be applied regardless of age, sex, body mass index (BMI) and height in adults.

Ultrasound-Guided Interventional Procedures of the Wrist and Hand: Anatomy, Indications, and Techniques

Acute and chronic wrist and hand conditions are commonly seen by neuromuscular and musculoskeletal specialists. High-frequency diagnostic ultrasonography (US) has facilitated advances in the diagnosis and interventional management of wrist and hand disorders. US provides excellent soft tissue resolution, accessibility, portability, lack of ionizing radiation, and the ability to dynamically assess disorders and precisely guide interventional procedures. This article review the relevant anatomy, indications, and interventional techniques for common disorders of the wrist and hand, including radiocarpal joint arthritis, scaphotrapeziotrapezoidal joint arthritis, trapeziometacarpal joint arthritis, phalangeal joint arthritis, first dorsal compartment tenosynovitis, ganglion cysts, and stenosing tenosynovitis.

Identification of the Position and Thickness of the First Annular Pulley in Sonographic Images

The purpose was to identify the A1 pulley's exact location and thickness by comparing measurements from a clinical high-frequency ultrasound scanner system (CHUS), a customized high-frequency ultrasound imaging research system (HURS) and a digital caliper. Ten cadaveric hands were used. We explored the pulley by layers, inserted guide pins and scanned it with the CHUS. After identifying the pulley, we measured each long finger's thickness using the CHUS and excised the pulley to measure its thickness with a digital caliper and the HURS. The thin hypo-echoic layer was revealed to be the synovial fluid space, and the pulley appears hyper-echoic regardless of scan direction. We also defined the pulley's boundaries. Moreover, the CHUS provided a significantly lower measurement of the pulley's thickness than the digital caliper and HURS. Likewise, based on the digital caliper's measurement, the HURS had significantly lower mean absolute and relative errors than the CHUS.

Comparison of the Thickness of Pulley and Flexor Tendon Between in Neutral and in Flexed Positions of Trigger Finger

Objective:

This study aims to compare the morphology of the A1 pulley and flexor tendons in idiopathic trigger finger of digits other than the thumb between in neutral position and in the position with the interphalangeal joints full flexed and with the metacarpophalangeal (MP) joint 0° extended (hook grip position).

Method:

A total of 48 affected digits and 48 contralateral normal digits from 48 patients who initially diagnosed with idiopathic trigger finger were studied sonographically. Sonographic analysis was focused on the A1 pulley and flexor tendons at the level of the MP joint in the transverse plane. We measured the anterior-posterior thickness of A1 pulley and the sum of the flexor digitorum superficialis and profundus tendons, and also measured the maximum radialulnar width of the flexor tendon in neutral and hook grip positions, respectively. Each measurement was compared between in neutral and in hook grip positions, and also between the affected and contralateral normal digits in each position.

Results:

In all the digits, the anterior-posterior thickness of flexor tendons significantly increased in hook grip position as compared with in neutral position, whereas radial-ulnar width significantly decreased. Both the A1 pulley and flexor tendons were thicker in the affected digits as compared with contralateral normal digits.

Conclusion:

The thickness of flexor tendons was significantly increased anteroposteriorly in hook grip position as compared with in neutral position. In trigger finger, A1 pulley and flexor tendon were thickened, and mismatch between the volume of the flexor tendon sheath and the tendons, especially in anterior-posterior direction, might be a cause of repetitive triggering.

US-guided Percutaneous Release of the Trigger Finger by Using a 21-gauge Needle: A Prospective Study of 60 Cases

Purpose To evaluate the efficacy of ultrasonographically (US)-guided percutaneous treatment of the trigger finger by releasing the A1 pulley with a 21-gauge needle. Materials and Methods This two-part study was approved by the ethics committee, and written consent was obtained from all patients. The first part consisted of 10 procedures on cadaver digits followed by dissection to analyze the effectiveness of the A1 pulley release and detect any collateral damage to the A2 pulley, interdigital nerves, or underlying flexor tendons. The second part was performed during an 18-month period starting in March 2013. It was a prospective clinical study of 60 procedures performed in 48 patients. Outcomes were evaluated through a clinical examination at day 0 and during a 6-month follow-up visit, where the trigger digit was evaluated clinically and the Quick Disabilities of the Arm, Shoulder and Hand outcome measure, or QuickDASH, and patient satisfaction questionnaires were administered. Results No complications were found during the cadaver study. However, the release was considered "partial" in all fingers. In the clinical study, the trigger finger was completely resolved in 81.7% (49 of 60) of cases immediately after the procedure. Moderate trigger finger persisted in 10 cases, and one thumb pulley could not be released. A US-guided corticosteroid injection was subsequently performed in these 11 cases. At 6-month follow-up, only two cases still had moderate trigger finger and there were no late complications. The mean QuickDASH questionnaire score was 4; all patients said they were satisfied. Conclusion US-guided treatment of the trigger finger by using a 21-gauge needle is feasible in current practice, with minimal complications. (©) RSNA, 2016 Online supplemental material is available for this article.

Comparative study on the effectiveness of corticosteroid injections between trigger fingers with and without proximal interphalangeal joint flexion contracture

Trigger fingers with proximal interphalangeal joint flexion contracture are suggested to have a poorer response to corticosteroid injection than those without contracture, though this has not been proven scientifically. We compared the clinical response to corticosteroid injection between trigger fingers with and without proximal interphalangeal joint contracture, and investigated the influence of the injection on the A1 pulley and flexor digitorum tendons using ultrasonography. One month after injection, pain was significantly reduced in the no contracture group, and 56% of trigger fingers with proximal interphalangeal joint contracture resolved. Before injection, relative thickening of the A1 pulley and flexor digitorum tendons, and a partial hypoechoic lesion of the flexor digitorum superficialis tendon were observed in the contracture group. One month after injection, the thickening of the tendons and the A1 pulley was reduced, but the partial hypoechoic lesion was still observed in significant numbers. We have demonstrated that the presence of a proximal interphalangeal joint contracture was associated with a reduced clinical response to corticosteroid injection, and we suggest that the pathologic change in the flexor digitorum superficialis tendon, represented by the partial hypoechoic lesion, contributed to corticosteroid injection resistance.

LEVEL OF EVIDENCE

IV.

Current status of ultrasonography of the finger

The recent development of advanced high-resolution transducers has enabled the fast, easy, and dynamic ultrasonographic evaluation of small, superficial structures such as the finger. In order to best exploit these advances, it is important to understand the normal anatomy and the basic pathologies of the finger, as exemplified by the following conditions involving the dorsal, volar, and lateral sections of the finger: sagittal band injuries, mallet finger, and Boutonnière deformity (dorsal aspect); flexor tendon tears, trigger finger, and volar plate injuries (volar aspect); gamekeeper's thumb (Stener lesions) and other collateral ligament tears (lateral aspect); and other lesions. This review provides a basis for understanding the ultrasonography of the finger and will therefore be useful for radiologists.

Sonographic evaluation of effects of the volar plate on trigger finger

BACKGROUND

We evaluated trigger fingers ultrasonographically and clarified differences between fingers with and without continuous locking or snapping symptoms according to the thicknesses of the A1 pulley, flexor tendon and volar plate.

METHODS

We evaluated 26 trigger fingers, divided into two groups: Group 1, 14 fingers with locking or snapping; and Group 2, 12 fingers without such symptoms. We also evaluated 26 contralateral fingers as controls (Control 1 and 2 groups). We compared each group to the respective control group according to thickness of the A1 pulley and volar plate, and cross-sectional area of the flexor tendon. In addition, nine fingers with locking or snapping and treated using corticosteroid injection were evaluated according to symptoms and sonographic findings 3-4 weeks after treatment.

RESULTS

Thickness of the A1 pulley and cross-sectional area of the flexor tendon were greater in both Groups 1 and 2 than in controls. Thickness of the volar plate was greater in Group 1 than in Control 1, although no significant difference was seen between Group 2 and Control 2. In Group 1, eight of the nine fingers showed an alleviation of locking or snapping symptoms with corticosteroid injection, and sonographic findings showed that thickness of the volar plate was significantly decreased with corticosteroid injection, in addition to reduced thickness of the A1 pulley.

CONCLUSION

In addition to thickening of the A1 pulley, thickening of the volar plate may represent an important contributor to continuous snapping or locking symptoms.

Trigger Finger: Adult and Pediatric Treatment Strategies

Trigger fingers are common tendinopathies representing a stenosing flexor tenosynovitis of the fingers. Adult trigger finger can be treated nonsurgically using activity modification, splinting, and/or corticosteroid injections. Surgical treatment options include percutaneous A1 pulley release and open A1 pulley release. Excision of a slip of the flexor digitorum superficialis is reserved for patients with persistent triggering despite A1 release or patients with persistent flexion contracture. Pediatric trigger thumb is treated with open A1 pulley release. Pediatric trigger finger is treated with release of the A1 pulley with excision of a slip or all of the flexor digitorum superficialis if triggering persists.

Leiomyoma in the thumb causing trigger finger

Leiomyoma is a generally benign tumour and common in the uterine smooth muscle. In some cases, it is found in other parts of the human body. In our study, we report the case of a 61-year-old woman with a painless cystic lesion on the first left thumb associated with trigger finger. The first diagnostic hypotheses were ganglionic cyst and giant cell tumour, however, after surgical excision and histological analysis, it was revealed to be a rare leiomyoma of the hand. We report a clinical case and detailed histopathological study, with 12 high-resolution images stained with: H&E, Smooth Muscle Actin, Desmin, S-100 and CD34.

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.

Ultrasound of the hand and wrist

There have been immense technical innovations and broadened clinical applications of ultrasound in the musculoskeletal system over the past 20 years. Specifically with regard to the hand and wrist, the advent of higher resolution transducers and postprocessing software applications have resulted in overall enhanced visualization of soft tissue structures (tendons/ligaments) as well as surface osseous lesions such as subclinical erosions in rheumatoid arthritis. Quantitative ultrasound, using either power Doppler or contrast-enhanced imaging, has become a central outcomes measure used to evaluate and document patient response to treatment in inflammatory arthropathies such as rheumatoid arthritis. This review will summarize the current state of clinical applications of ultrasound in the evaluation of the hand and wrist, with a summary of technical advances and specific applications in rheumatologic conditions.This review was exempt from institutional review board approval.

Role of sonographic imaging in occupational therapy practice

Occupational therapy practice is grounded in the delivery of occupation-centered, patient-driven treatments that engage clients in the process of doing to improve health. As emerging technologies, such as medical imaging, find their way into rehabilitation practice, it is imperative that occupational therapy practitioners assess whether and how these tools can be incorporated into treatment regimens that are dually responsive to the medical model of health care and to the profession's foundation in occupation. Most medical imaging modalities have a discrete place in occupation-based intervention as outcome measures or for patient education; however, sonographic imaging has the potential to blend multiple occupational therapy practice forms to document treatment outcomes, inform clinical reasoning, and facilitate improved functional performance when used as an accessory tool in direct intervention. Use of medical imaging is discussed as it relates to occupational foundations and the professional role within the context of providing efficient, effective patient-centered rehabilitative care.

Sonographic findings of extensor digiti minimi triggering caused by thickened extensor retinaculum

Trigger finger is a common well recognized condition and involves the flexor tendons at the A1 pulley in the palm. Triggering of the extensor tendons is a very rare clinical entity. We report a rare case of extensor triggering of little finger caused by constriction of the extensor digiti minimi by a markedly thickened extensor retinaculum (ER) at the wrist, well delineated dynamically by real-time high-resolution ultrasound. The patient underwent release of thickened ER and was asymptomatic immediately.

Sonographic analyses of pulley and flexor tendon in idiopathic trigger finger with interphalangeal joint contracture

This study investigated the sonographic appearance of the pulley and flexor tendon in idiopathic trigger finger in correlation with the contracture of the interphalangeal (IP) joint in the thumb or proximal IP (PIP) joint in the other digits. Sonographic measurements using axial images were performed in 177 affected digits including 17 thumbs and 34 other digits judged to have IP or PIP joint contracture and 77 contralateral control digits. The A1 pulley of the contracture group was significantly thicker than that of the non-contracture group in all digits, whereas the flexor tendon was thicker only in digits other than the thumb. In the analysis using calculated cut-off values, A1 pulley thickening in the thumb and A1 pulley and flexor tendon thickening in the other digits showed statistically significant correlations with IP or PIP joint contracture. This study sonographically confirmed previous reports showing that enlargement of the flexor tendons contribute to the pathogenesis of PIP joint contracture.