Ultrasonography-guided percutaneous release of A3 pulley of the fifth finger to treat trigger finger: Description of the technique, with reference to a specific case.

Trigger finger causes pain and a persistent functional limitation of the hand, which can lead to permanent blockage of the flexor tendon. Ultrasonography-guided percutaneous release has been widely reported as a successful technique for trigger finger involving the A1 pulley. This article describes for the first time the use of this technique in an unusual location, the A3 pulley of the fifth finger. A 71-year-old patient presented with a 3-month history of pain and blockage in the fifth finger of the right hand and was diagnosed with a grade III trigger finger, according to the Froimson scale. We performed an ultrasonography-guided percutaneous release technique on the A3 pulley to release the flexor tendon of the fifth finger. Ultrasonography-guided percutaneous polectomy to treat trigger finger in the A1 pulley is an effective alternative treatment to surgery and even has certain advantages over it. The anatomical similarity between the A1 and A3 pulleys was the key factor that supported the use of this technique in this clinical case. Based on past experience in similar cases, we conclude that ultrasonography-guided percutaneous polectomy of the A3 pulley of the fifth finger was a surgical technique which could lead to a satisfactory outcome in the treatment of this condition.

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.

Efficacy of Minimally Invasive Ulnar Superficialis Slip Resection for Unfavourable Results after Trigger Finger Release.

Background: This study aimed to evaluate the efficacy of ulnar superficial slip resection (USSR) for improving hand function after unfavourable results after triggering finger release using a minimally invasive approach. Methods: We evaluated 17 consecutive fingers of 16 patients who complained of unfavourable outcomes after primary trigger finger release. The chief complaints of the two index and 15 middle fingers were proximal interphalangeal (PIP) joint pain during movement, flexion contracture of the PIP joint and snapping at the A2 pulley in eight, seven and two fingers, respectively. The joint arc of the active range of motion and extension loss of the PIP joint, grip strength, visual analogue score (VAS) of PIP joint pain and Quick Disability of the Arm, Shoulder and Hand were evaluated before and after surgery. Results: Thirteen fingers could release joint contracture and snapping by the USSR procedure. However, four fingers of three patients required total flexor digitorum superficialis resection to resolve the unsatisfactory conditions of the intraoperative decision. The joint arc of active range of motion and extension loss of the PIP joint, grip strength and VAS score significantly improved (mean of 16.1 months follow-up). Finally, 15 patients (88.2%) were satisfied with the symptom relief outcomes. Conclusions: USSR is an effective and satisfactory procedure for unfavourable conditions after trigger finger release, including PIP joint pain, joint contracture and snapping at the A2 pulley. Level of Evidence: Level IV (Therapeutic).

Is arthritis an associated risk factor for trigger finger occurrence after carpal tunnel release? A nationwide, population-based study in Korea.

PURPOSE: We hypothesized that increased friction between the flexor tendon and surrounding structures due to hand arthritis is an important risk factor for trigger finger (TF) after carpal tunnel release (CTR). Therefore, we compared TF development according to the presence or absence of arthritis in carpal tunnel syndrome (CTS) patients treated with CTR. METHODS: This retrospective study was based on data collected from the National Health Insurance Service-National Sample Cohort (NHIS-NSC) in the Republic of Korea between January 1, 2002, and December 31, 2015. Patients diagnosed with TF between one month and one year after the CTR date or with a history of surgery were included in the study. During subsequent follow-up, the patients were divided into subgroups of those (1) with TF and (2) without TF. Sex, age, arthritis, and TF-related comorbidities were compared between the subgroups. RESULTS: The subgroup with TF had a higher proportion of women (9.43% vs 90.57%), the highest age range between 50 and 59 years, more cases of arthritis (32.55% vs 16.79%), and a higher proportion of patients with hypothyroidism (10.85% vs 4.60%) than the group without TF. The association between arthritis and TF after CTR was examined using a multivariate logistic regression model, showing arthritis to be a significant risk factor for TF after CTR (odds ratio, 1.35; P = 0.049). CONCLUSIONS: We identified arthritis as an important risk factor for the development of TF after CTR.

Hyperglycaemia is a causal risk factor for upper limb pathologies.

BACKGROUND: Diabetes (regardless of type) and obesity are associated with a range of musculoskeletal disorders. The causal mechanisms driving these associations are unknown for many upper limb pathologies. We used genetic techniques to test the causal link between glycemia, obesity and musculoskeletal conditions. METHODS: In the UK Biobank's unrelated European cohort (N = 379 708) we performed mendelian randomisation (MR) analyses to test for a causal effect of long-term high glycaemia and adiposity on four musculoskeletal pathologies: frozen shoulder, Dupuytren's disease, carpal tunnel syndrome and trigger finger. We also performed single-gene MR using rare variants in the GCK gene. RESULTS: Using MR, we found evidence that long-term high glycaemia has a causal role in the aetiology of upper limb conditions. A 10-mmol/mol increase in genetically predicted haemoglobin A1C (HbA1c) was associated with frozen shoulder: odds ratio (OR) = 1.50 [95% confidence interval (CI), 1.20-1.88], Dupuytren's disease: OR = 1.17 (95% CI, 1.01-1.35), trigger finger: OR = 1.30 (95% CI, 1.09-1.55) and carpal tunnel syndrome: OR = 1.20 (95% CI, 1.09-1.33). Carriers of GCK mutations have increased odds of frozen shoulder: OR = 7.16 (95% CI, 2.93-17.51) and carpal tunnel syndrome: OR = 2.86 (95% CI, 1.50-5.44) but not Dupuytren's disease or trigger finger. We found evidence that an increase in genetically predicted body mass index (BMI) of 5 kg/m2 was associated with carpal tunnel syndrome: OR = 1.13 (95% CI, 1.10-1.16) and associated negatively with Dupuytren's disease: OR = 0.94 (95% CI, 0.90-0.98), but no evidence of association with frozen shoulder or trigger finger. Trigger finger (OR 1.96 (95% CI, 1.42-2.69) P = 3.6e-05) and carpal tunnel syndrome [OR 1.63 (95% CI, 1.36-1.95) P = 8.5e-08] are associated with genetically predicted unfavourable adiposity increase of one standard deviation of body fat. CONCLUSIONS: Our study consistently demonstrates a causal role of long-term high glycaemia in the aetiology of upper limb musculoskeletal conditions. Clinicians treating diabetes patients should be aware of these complications in clinic, specifically those managing the care of GCK mutation carriers. Upper limb musculoskeletal conditions should be considered diabetes complications.

Efficacy of Ultrasound-Guided Tendon Release for Trigger Finger Compared With Open Surgery: A Systematic Review and Meta-Analysis.

BACKGROUND: Trigger finger (also known as stenosing tenosynovitis) is a chronic inflammatory disorder that affects the fingers and causes discomfort and functional impairment. It is estimated to affect 2-3.6% of the population and is more common in manual laborers and individuals engaged in repetitive hand activities. This study comprehensively compares the efficacy of ultrasound-guided release versus traditional open surgery in treating trigger fingers. MATERIALS: We systematically searched PubMed, Scopus, EMBASE, and the Cochrane Library to identify relevant studies. Inclusion criteria were studies evaluating ultrasound-guided release of trigger finger (grade 2 and higher) compared with open surgical release. A meta-analysis was performed by Revman software 5.4.1 to assess efficacy, utilizing appropriate statistical methods to address heterogeneity. Primary outcome measures included "Quick Disability of Arm, Shoulder, and Hand" (QDASH) scores, Grip strength, and the Visual Analogue Scale (VAS). Secondary outcome measures included Days of stopping analgesia, full-digit flexion and extension, days to return to normal activities, pinch strength, Quinnell grading score, and bow strengthening. RESULTS: Out of the initial pool of 820 studies, five met the inclusion criteria, including 275 patients with 283 trigger digits. The analysis revealed significant differences favoring the ultrasound-guided release group over the surgical group for improvement in Quick Disability of Arm, Shoulder, and Hand score in the first month (MD -0.48, 95% CI: 0.75 to -0.2, P = .0007, I2 = 20%). The difference was not statistically significant in the 3-month follow-up period (MD -2.25, 95% CI: -0.54 to 0.05, P = .1, I2 = 0%). Additionally, there is a significant difference in the days required for return to normal activities in favor of the ultrasound release approach (MD -13.78, 95% CI: -16.68 to 10.89, P = .00001, I2 = 68%). The data displayed heterogeneity, which was resolved through sensitivity analysis that also favored the ultrasound-guided group. In terms of grip strength, full-digit flexion and extension, VAS, and days of stopping analgesia no significant differences were observed. CONCLUSIONS: Ultrasound-guided release showed advantages over open surgical release, resulting in improved QDASH score and quicker return to normal activities. This offers a minimally invasive, successful alternative to open surgery, reducing associated risks. Further studies with long-term follow-up are recommended.

Factors Influencing the Successful Treatment of Recurrent Trigger Finger With Repeated Corticosteroid Injections: A Prospective Cohort Study.

PURPOSE: The aim of this study was to determine the success rate, duration of disease control, and predictive factors of success of repeated corticosteroid injections for recurrent trigger finger. METHODS: This prospective cohort study involved patients who had recurrent trigger finger and a history of corticosteroid injections. A total 114 patients were treated with repeated corticosteroid injections and followed for 12 months. Data on demographic characteristics, comorbid conditions, and possible predictive factors for successful treatment from medical chart reviews and direct patient interviews were compared. Patients were classified into success or failure groups at one, three, six, and 12 months after the initial injection. The relationship between hypothesized predictors and success or failure after repeated corticosteroid injection was analyzed with multivariable logistic regression. RESULTS: The overall success rates from repeated cortisone injections after one, three, six, and 12 months were 97.4%, 84.2%, 68.4%, and 49.1%, respectively. Multivariable logistic regression modeling revealed that a high grade of disease (grade III or IV based on the Quinnell system), a body mass index (BMI) ≥ 25 kg/m2, and a short symptom-free period (< six months) after a previous injection were strong predictors of symptom recurrence (odds ratio = 3.6 [95% CI 1.5-8.4], odds ratio = 2.5 [95% CI 1.1-5.9], and odds ratio = 1.8 [95% CI 1.1-3.0], respectively). The average success rates for patients at 1-year according to the number of risk factors were as follows: none of the three risk factors, 73.3%; one risk factor, 54.2% to 63.6% (54.2% for grade III-IV triggering, 63.6% for BMI ≥ 25 kg/m2 and 63.6% for < 6-month symptom-free period); two risk factors, 30% to 75% (30% for a combination of grade III-IV and BMI ≥ 25 kg/m2, 45.5% with grade II-IV and < 6-month period, and 75% with a combination of < 6-month period and BMI ≥ 25 kg/m2); and all three risk factors, 11.8%. CONCLUSIONS: Repeated corticosteroid injections for recurrent trigger finger should be considered in patients who prefer nonsurgical treatment, especially in those without factors predictive of failure. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic II.

Flexor Tenosynovial Fistula as a Complication after Endoscopic Trigger Finger Release: A Case Report.

OBJECTIVE: We report a rare case of flexor tenosynovial fistula secondary to endoscopic release of the A1 pulley for treatment of trigger finger. CASE PRESENTATION: A 72-year-old woman underwent endoscopic release of the A1 pulleys of her left ring and right middle fingers. Nine days after surgery, the wound at the base of the proximal phalanx of the ring finger (distal portal) remained open and a clear liquid discharge was seen. The volume of discharge increased with active finger motion. However, there was no evidence of infection. The patient was diagnosed with tenosynovial fistula as a complication of endoscopic release of the A1 pulley. At day 30, the fistula and drainage persisted and the condition was managed by surgical excision of the fistula and primary closure. The wound then healed completely. CONCLUSION: Our report alerts hand surgeons to the potential development of flexor tenosynovial fistula as a very rare complication following endoscopic release of the A1 pulley for the treatment of trigger finger.

Musculoskeletal co-morbidities in patients with transthyretin amyloid cardiomyopathy: a systematic review.

The prevalence of transthyretin-associated amyloidosis cardiomyopathy (ATTR-CM) has grown because of newer non-invasive diagnosis tools. Detecting the presence of extra-cardiac ATTR manifestations such as musculoskeletal pathologies considered 'red flags', when there is minimal or non-cardiac clinical involvement is primordial to carry out an early diagnosis. The aim of this systematic review is to examine the prevalence of musculoskeletal, ATTR-deposition-related co-morbidities in patients already diagnosed with ATTR-CM, specifically carpal tunnel syndrome, ruptured biceps tendon, spinal stenosis, and trigger finger. We performed a systematic review using PRISMA guidelines. Inclusion criteria were all studies in English and Spanish language and participants had to be patients diagnosed with ATTR-CM, by any diagnostic method, with the musculoskeletal co-morbidities subject of this review. The quality of the studies was based on the Risk of Bias Tool. This systematic review included 22 studies for final analysis. Carpal tunnel syndrome is reported in 21 studies, brachial biceps tendon rupture is reported in three, and spinal stenosis in eight studies. No articles that accomplished all the inclusion criteria for trigger finger were found. Regarding to the quality of the studies, all of them were categorized as being of high and moderate quality. The frequent association between ATTR-CM and carpal tunnel syndrome, ruptured biceps tendon, and lumbar spinal is confirmed, and the onset of these co-morbidities usually precedes the diagnosis of by years. This association defines them as red flags that should be search proactively due to the current treatment possibilities and the severity of the presentation of cardiac amyloidosis.

Unique skin findings in a case of the A3 pulley trigger finger due to an osteochondroma.

Trigger finger is usually caused by stenosing tenosynovitis and hypertrophy of the retinacular sheath, and the most common site of tendon triggering is the A1 pulley. Although the A3 pulley trigger finger has been described in a few cases caused by hypertrophy of the retinacular sheath and ganglion, associated skin findings have not been reported to date. Herein, we report a rare case of the A3 pulley trigger finger due to osteochondroma with unique skin findings in a 50-year-old woman. In this case, we observed a V-shaped skin depression on the palmar side of the proximal interphalangeal joint of the right middle finger during finger locking. Additionally, we observed bilateral linear skin depressions on the sides of the proximal phalange. These findings might be caused by the traction force on the A3 pulley, connected to the skin via the Grayson and Cleland ligaments, which are fibrous tissues that connect the skin and tendon sheath.

Effects of socioeconomic status on patient-reported outcome after surgically treated trigger finger: a retrospective national registry-based study.

OBJECTIVES: To investigate if socioeconomic status impacts patient-reported outcomes after a surgically treated trigger finger (TF). DESIGN AND SETTING: Data on patients with TF treated with surgery were collected from the Swedish National Quality Registry of Hand Surgery (HAKIR) 2010-2019 with an evaluation of symptoms and disability before surgery and at 3 and 12 months after surgery, using the short version of the Disabilities of Arm, Shoulder and Hand (QuickDASH) questionnaire.Data from HAKIR and the Swedish National Diabetes Registry (ndr.nu) were combined with socioeconomic data from Statistics Sweden (scb.sc), analysing the impact of marital status, education level, income, occupation, sickness benefits, days of unemployment, social assistance and migrant status on the outcome by a linear regression model. PARTICIPANTS: In total, 5477 patients were operated on for primary TF during the study period, of whom 21% had diabetes, with a response rate of 35% preoperatively, 26% at 3 months and 25% at 12 months. RESULTS: At all time points, being born in Sweden (preoperatively B-coefficient: -9.74 (95% CI -13.38 to -6.11), 3 months postoperatively -9.80 (95% CI -13.82 to -5.78) and 12 months postoperatively -8.28 (95% CI -12.51 to -4.05); all p<0.001) and high earnings (preoperatively -7.81 (95% CI -11.50 to -4.12), 3 months postoperatively -9.35 (95% CI -13.30 to -5.40) and 12 months postoperatively -10.25 (95% CI -14.37 to -6.13); all p<0.0001) predicted lower QuickDASH scores (ie, fewer symptoms and disability) in the linear regression models. More sick leave during the surgery year predicted higher QuickDASH scores (preoperatively 5.77 (95% CI 3.28 to 8.25; p<0.001), 3 months postoperatively 4.40 (95% CI 1.59 to 7.22; p<0.001) and 12 months postoperatively 4.38 (95% CI 1.35 to 7.40; p=0.005)). No socioeconomic factors impacted the change in QuickDASH score from preoperative to 12 months postoperatively in the fully adjusted model. CONCLUSION: Individuals with low earnings, high sick leave the same year as the surgery and those born outside of Sweden reported more symptoms both before and after surgery, but the relative improvement was not affected by socioeconomic factors.

Identification of the length and location of the A1 pulley combining palpation technique with palm landmarks: a cadaveric study.

Through anatomical morphology, to accumulate the relevant parameters of the A1 pulley of each adult finger. A total of 100 fingers were selected, dissected layer by layer, and the A1 pulley and neurovascular of each finger were observed. Measure the length of the A1 pulley, the distance between the needle knife insertion point and the proximal edge of A1 pulley, and the nerves and blood vessels on both sides. (1) The length of A1 pulleys of each finger is 6.18 ± 0.33 mm, 6.58 ± 0.73 mm, 5.98 ± 0.67 mm, 5.36 ± 1.08 mm, 5.63 ± 1.09 mm. (2) The distances between the needle knife entry point of each finger and the volar proper nerve of the ulnar finger are 7.00 ± 1.55 mm, 8.29 ± 1.46 mm, 5.10 ± 0.25 mm, 5.30 ± 0.24 mm, 0 mm; the distances from the volar proper nerve of the radial finger are 9.08 ± 0.87 mm, 4.70 ± 1.10 mm, 7.03 ± 0.72 mm, 6.81 ± 0.22 mm, 7.81 ± 0.57 mm. (3) The distances between the needle knife entry point of each finger and the proper volar artery of the ulnar finger are 10.40 ± 0.75 mm, 8.89 ± 0.53 mm, 6.35 ± 0.44 mm, 7.26 ± 0.16 mm, 0 mm, respectively; The distances from the volar proper artery of the radial finger are 8.75 ± 1.07 mm, 6.10 ± 0.35 mm, 11.44 ± 0.41 mm, 8.19 ± 0.60 mm, 9.78 ± 0.68 mm, respectively. The landmarks of the needle entry points are located at the position corresponding to the highest point of the metacarpal heads, except the tail finger. From the needle knife entry point to distal, cut the proximal edge of the A1 pulley longitudinally along the midline until the patient can flex autonomously, and pay attention to the distance between the two sides of 3.60-11.85 mm neurovascular bundle.

Sonographically controlled minimally-invasive A1 pulley release using a new guide instrument - a case series of 106 procedures in 64 patients.

BACKGROUND: With percutaneous and minimally-invasive pulley release becoming more popular, safety and reliability of such minimally-invasive procedures remain a concern. Visualization of the technical steps by ultrasound suggests increased safety but shows the potential for harm to tendons, nerves and vessels without proper instrumentation. We present the results of implementing a sonographically guided minimally-invasive procedure in 106 trigger digits of 64 patients between 2018-2021. METHODS: A guide instrument for use with a commercially available hook knife was developed and tested in 16 cadaver hands. Due to complication early in our clinical series this guide was modified in due course. A revised design of the guide has been in use since November 2019 with improved performance and safety. RESULTS: One hundred six procedures in 64 patients were performed. After guide revision, we report a success rate of 97.3%. Complications after instrument revision include two cases of incomplete pulley release and one case of inadvertent skin laceration. The majority of patients report returning to all strenuous activities within two weeks at most apart from four individuals with prolonged postoperative discomfort. CONCLUSION: We present the results of the development and implementation of a novel guide instrument for use with a hook knife to treat trigger finger. Despite several limitations of this study, we show that sonographically controlled, minimally-invasive A1 pulley release can be performed safely and effectively with appropriate surgical instruments and practice.

Health-related factors and dysregulation of epigenetic related genes in metabolic syndrome trigger finger patients and smoker trigger finger patients: preliminary analysis of patient-derived sample.

PURPOSE: To investigate the health-related factors and analyze the expression of epigenetic related genes and inflammatory genes in metabolic syndrome Trigger Finger (TF) and smoker TF. METHODS: Samples from patients' fingers with symptomatic TF were collected. There were seven groups: healthy control group, carpal tunnel syndrome (as a control for gene expression analysis), TF, diabetic TF, hypertensive TF, dyslipidemic TF and smoker TF. The expression levels of epigenetic related genes and inflammatory genes in metabolic syndrome TF and smoker TF were evaluated by the reverse transcription-polymerase chain reaction (RT-PCR) technique. The Perceived Stress Scale (PSS), Pittsburgh Sleep Quality Index (PSQI) questionnaires, disability of the arm, shoulder and hand (DASH) and numeric pain rating scale were given to the participants to fill out. RESULTS: There was a significant increase in hand dysfunction in the metabolic TF groups and smoker group compared to the TF group (p < 0.0001). The stress levels of the smoker TF group and TF with hypertension group were significantly increased compared with those in the TF group (p < 0.03) and (p < 0.021), respectively. On the other hand, there was a significant increase in the COL-I, COL-II and TNF-α gene expression of the metabolic TF groups and smoker group (p < 0.0001). CONCLUSIONS: Health-related factors in the TF tendons was highly associated with the level of inflammation and genetic alteration in TF metabolic syndromes and smoker TF patients. Therefore, further investigation is required to examine the combination of occupational therapy, gene expression, and health-related factors as a promising method of managing TF.

[Trigger finger: to operate or to inject?] / Trigger finger: opereren of injecteren?

Trigger finger is a common hand disorder in which swelling of the affected flexor-tendon results in triggering, locking or pain at the A1-pulley and impaired function of the finger. In this clinical lesson we describe 4 cases of patients with this condition, illustrating the clinical picture of trigger finger and how decisions regarding treatment are made. In typical cases the diagnosis is straight forward, but if the clinical presentation is less clear (e.g. in case if there is only pain at the A1-pully or a locked finger) making the diagnosis can be challenging. Conservative (doing nothing, orthosis, injection) and operative treatment options are discussed. Guiding principles are formulated which may help in choosing the most appropriate treatment for individual patients.

Ultrasound-guided acupotomy for trigger finger: a systematic review and meta-analysis.

BACKGROUND: Trigger finger is a common condition in the hand, and ultrasound-guided acupotomy for trigger finger has been widely used in recent years. PURPOSE: This study aims to investigate the efficacy and safety of ultrasound-guided acupotomy for trigger finger. METHODS: We searched for relevant studies in the Cochrane Library, China National Knowledge Infrastructure (CNKI), Embase, PubMed, Chinese Biomedical Literature Database (CBM), Wanfang Data, and other resources from their inception to January 2023. Randomized controlled trials of ultrasound-guided acupotomy for trigger finger were included. The meta-analysis was carried out using Review Manager 5.4 and Stata 15.1. RESULTS: Overall, 15 studies with 988 patients were included. The experimental group was treated with ultrasound-guided acupotomy, and the Control group received traditional acupotomy, traditional operation or injection of medication. Meta-analysis showed that the overall clinical effectiveness (OR = 4.83; 95% CI 2.49-9.37; I2 = 73.1%; P < 0.001) in the experimental group was significantly better than that of the control group. And the Visual Analogue Scale (VAS) score (WMD = - 1; 95% CI - 1.24, - 0.76; I2 = 99%; P < 0.001), the QuinneII classification (WMD = - 0.84; 95% CI - 1.28, - 0.39; I2 = 99.1%, P < 0.001), the incidence of complications (RR = 0.26; 95% CI 0.11, 0.63; I2 = 0%, P = 0.003), and the recurrence rate (RR = 0.14; 95% CI 0.03, 0.74; I2 = 0%; P = 0.021) were significantly lower in the experimental group. CONCLUSION: Our systematic review and meta-analysis can prove the effectiveness and safety of ultrasound-guided acupotomy in the treatment of trigger finger, but this still needs to be verified by a clinical standard large sample test.

Changes in flexor pollicis longus tendon cross-sectional dimensions after A1 pulley release for paediatric trigger thumb.

In this study, 30 patients with unilateral paediatric trigger thumb were examined with measurements taken within 1 month before surgery, and at 3 months after surgery. We measured the dorsal-palmar (DP) diameter, radioulnar (RU) diameter and cross-sectional area (CSA) of the flexor pollicis longus (FPL) tendon at two sites: just proximal to the A1 pulley and underneath the A1 pulley using ultrasonography. Following surgical A1 pulley release, the DP diameter, RU diameter and CSA of the FPL tendon just proximal to the A1 pulley significantly decreased from 2.6 mm to 2.2 mm, from 5.1 mm to 4.2 mm and from 11 mm2 to 7.8 mm2, respectively. Additionally, the RU diameter and CSA of the FPL tendon at the area beneath the A1 pulley significantly increased from 2.2 mm to 3.2 mm and from 4.3 mm2 to 5.8 mm2, respectively. This finding suggests that the conformation of the FPL tendon of the affected thumb tends to return to that of the contralateral uninvolved thumb after A1 pulley release. Underdevelopment of the inner space around the A1 pulley may contribute to the development of paediatric trigger thumb.Level of evidence: III.