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.

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.

Ultrasound-guided percutaneous opening of the A1 pulley with surgical knife on anterograde versus retrograde approach: A comparative cadaver study (40 fingers).

OBJECTIVE: Trigger finger is one of the most common pathologies of the finger flexor mechanism. Previous studies have shown the value of ultrasound-guided percutaneous tenolysis. The aim of this study was to compare the efficacy and safety of anterograde versus retrograde percutaneous ultrasound-guided tenolysis. MATERIALS AND METHODS: This was a comparative cadaver study performed between December 2021 and April 2022 in France, with 40 fresh cadaver fingers. Thumbs were excluded. A single surgeon performed 20 ultrasound-guided anterograde releases and 20 ultrasound-guided retrograde releases, using a second-generation minimally invasive surgical knife, and a multipurpose linear ultrasound transducer. The primary endpoint was the success of ultrasound-guided release, defined as complete opening of the A1 pulley along its entire length. RESULTS: The success rate was 90% in the retrograde group and 95% in the anterograde group (non-significant difference: p = 0.56). There was no significant difference in superficial flexor tendon slip injuries or partial A2 pulley injuries. There were no neurovascular pedicle lesions. CONCLUSION: The choice of anterograde or retrograde ultrasound-guided tenolysis should be left to the surgeon's discretion.

Combination of ultrasound-guided percutaneous A1 pulley release and intra-tendon sheath injection improves the therapeutic outcomes in adult trigger finger patients.

AIM: This study aimed to use high-frequency ultrasound guidance to compare the efficacy of percutaneous release combined with intra-tendon sheath injection (PR-ITSI) and percutaneous release only (PR-ONLY) in the treatment of adult trigger finger (TF) patients. MATERIALS AND METHODS: A total of 48 patients were randomly divided into PR-ITSI group and PR-ONLY group. The thickness of the A1 pulley was measured prior to surgery and 1-year after surgery. Visual Analogue Scale (VAS) score and Patient Global Impression of Improvement (PGI-I) scale score of affected fingers were evaluated at 1 day, 1 month, and 1 year after surgery. RESULTS: The overall difference of VAS score between the two groups after treatment was statistically significant (p<0.001), while the VAS scores gradually decreased in both groups at different time-points after treatment. The VAS scores in the PR-ITSI group at 1 day and 1 month after surgery were 1.475 and 0.904 (p<0.001), respectively, which were lower than those in the PR-ONLY group. Different treatment methods had no effect on the VAS score at 1 year after surgery (p=0.055). The thickness of the A1 pulley at 1 year after surgery was lower than that before surgery (p<0.001), whereas there was no significant difference in A1 pulley thickness between the two groups (p=0.095). The rate of PGI-I scale improvement by one grade at 1 day, 1 month, and 1 year after surgery in the PR-ITSI group was 15.322 times (95%CI: 4.466-52.573, p<0.001), 14.807 times (95%CI: 2.931-74.799, p=0.001), and 15.557 times (95%CI: 1.119-216.307, p=0.041), respectively, than that in the PR-ONLY group. CONCLUSION: Ultrasound-guided PR-ITSI is superior to PR-ONLY in the VAS score and PGI-I scale for adult TF patients.

Ultrasound guided versus blinded injection in trigger finger treatment: a prospective controlled study.

BACKGROUND: Trigger finger is a common disease with a lifetime prevalence of 2%. One of the frequently preferred non-surgical treatments is blinded injection around the A1 pulley. This study aims to compare the clinical results of ultrasound-guided and blinded corticosteroid injection in the trigger finger. METHODS: In this prospective clinical study, 66 patients who had persistent symptoms of a single trigger finger were included. Patients with similar baseline characteristics such as age, gender, triggering period, and comorbidities were randomized. 34 patients had ultrasound-guided (UG), and 32 had blinded injections (BG). QDASH, VAS, time to return to work, and complications were compared between the groups. RESULTS: The mean age was 52,66 (29-73) years. There were 18 male and 48 female patients. In the UG, the triggering resolved faster, returning to work was earlier, and the medication period was shorter (p < 0.05). A total of 17 patients who had diabetes mellitus received re-injections, 11 of which were in BG and 6 in UG (p < 0.05). Although statistically significantly lower scores were obtained in UG at the 1st and 4th weeks in the QDASH and VAS scores (p < 0.05), at the 12th and 24 weeks, there was no significant difference (p > 0.05). CONCLUSION: Using ultrasound guidance for corticosteroid injections is more effective for treating trigger fingers than the blinded method, leading to better results and a faster return to work in the early stages of treatment.

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.

A Comparison of the Outcomes of Open Trigger Release versus Ultrasound-Guided Modified Small Needle-Knife Percutaneous Release for Treatment of Trigger Digits.

Background: The aim of this randomised prospective study is to compare the outcomes of traditional open trigger digit release versus ultrasound-guided modified small needle-knife (SNK) percutaneous release in the treatment of trigger digits. Methods: Patients with grade 2 and above trigger digits were enrolled into the study and randomly assigned to traditional open surgery (OS) or ultrasound-guided modified SNK percutaneous release group. The patients were followed up for 7, 30 and 180 days after treatment and data with regard to visual analogue scale (VAS) score and Quinnell grading (QG) was collected and compared between the two groups. Results: A total of 72 patients were enrolled in the study with 30 in the OS group and 42 in the SNK group. VAS scores and QG of the two groups significantly decreased at 7 days and 30 days after treatment compared to before treatment, but there was no significant difference between the two groups. There was also no differences between the two groups at 180 days and between the values at 30 days and 180 days. Conclusions: The outcomes of ultrasound-guided SNK percutaneous release is similar to traditional OS. Level of Evidence: Level II (Therapeutic).

Trigger Finger Due to Anomaly of Lumbrical Insertion: A Case Report and Review of Literature.

CASE: Trigger finger (TF), or stenosing synovitis, is a common condition that can usually be diagnosed by physical examination. We recently operated on a patient with TF who did not respond to conservative treatment. At surgery, we found an anomalous insertion of the fourth lumbrical muscle to the A1 pulley. This insertion was observed to cause mechanical narrowing of the pulley due to a pulling effect by the muscle, which was relieved by resection. CONCLUSION: Although rare, the operating surgeon should be aware that local anatomical anomalies, such as insertion of a lumbrical into the A1 pulley, can be a cause of trigger finger.

Ultrasound-Guided A1 Pulley Release Versus Classic Open Surgery for Trigger Digit: A Randomized Clinical Trial.

OBJECTIVES: We compared an ultra-minimally invasive ultrasound-guided percutaneous A1 pulley release and a classic open surgery for trigger digit. METHODS: We designed a single-center randomized control trial. All cases had clinical signs of primary grade III trigger digit. Concealed allocation (1:1) was used for assigning patients to each group and data collectors were blinded. The Quick-Disabilities of the Arm, Shoulder, and Hand (Quick-DASH) questionnaire was our primary variable. Quick-DASH, two-point discrimination, grip strength, time until stopping analgesics, having full digital range of motion and restarting everyday activities were registered on the 1st, 3rd, and 6th weeks, 3rd and 6th months, and 1st year after the procedure. RESULTS: We randomized 84 patients to ultrasound-guided release and classic open surgery. Quick-DASH scores significantly favored the percutaneous technique until the 3rd month: 7.6 ± 1.2 versus 15.3 ± 2.4 (mean ± standard error of the mean). The percutaneous group obtained significantly better results in all the variables studied: time until stopping analgesics, achieving full range of motion and restarting everyday activities. Grip strength was significantly better in the percutaneous group for the 1st week only. Five cases of moderate local pain were observed in the open technique. There was one case of transient nerve numbness per group. CONCLUSIONS: The ultra-minimally invasive ultrasound-guided A1 pulley release was clinically superior to the classic open surgery in functional recovery with a lower complication rate.

Complex trigger wrist associated with carpal tunnel syndrome: a case report.

BACKGROUND: There are few reports of trigger wrist in the literature, as it is a rare pathology. Furthermore, various authors report that it is also hard to diagnose. It manifests with neurological symptoms at the affected wrist, which are usually induced by wrist movement, and can lead to partial or full loss of wrist function and sensitivity. The reason for reporting this specific case is that it was hard to differentiate between trigger finger and trigger wrist by clinical symptoms; no pathology was palpable or clearly seen on magnetic resonance imaging scan of the wrist. We propose a new diagnostic statement relative to this pathology. CASE PRESENTATION: A case of a 45-year-old white slavic man with trigger wrist associated with carpal tunnel syndrome, caused by a fibroma of the flexor tendon sheath, is reported. Despite careful clinical examination, it was not possible to differentiate between trigger finger and trigger wrist. Magnetic resonance imaging was performed to arrive at the right diagnosis but did not reveal any pathology in the wrist area. Carpal tunnel release was performed with a fibroma identified and excised. Wrist function was maintained well; no signs of carpal tunnel syndrome were seen at last follow-up. CONCLUSIONS: Trigger wrist can be misdiagnosed as trigger finger even if adequate clinical evaluation is performed, and this can lead to inadequate treatment. We state that, when clinical symptoms of both trigger wrist and trigger finger are present, except painful palpation of the A-1 pulley region, the case should be referred to as trigger wrist.

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.

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.

Changes in the flexor pollicis longus tendon during spontaneous resolution of pediatric trigger thumb.

The present study aimed to evaluate conformational changes in the flexor pollicis longus (FPL) tendon and inner space of the A1 pulley during spontaneous resolution of pediatric trigger thumb (PTT) and to compare them versus the normal contralateral side. We enrolled 36 patients with unilateral PTT who underwent ultrasonography twice between January 2016 and July 2020 and showed >10° improvement in thumb interphalangeal (IP) joint extension lag. Ultrasonography was used to measure the anteroposterior (AP) and radioulnar (RU) diameters of the FPL tendon proximal to the A1 pulley and of the inner space of the A1 pulley. On the side of the PTT, the average extension lag in the thumb IP joint significantly improved, from 35.6° to 14.2°. The AP and RU diameters of the FPL tendon increased by 0.3% and 1.9%, respectively, and those of the inner space of the A1 pulley increased by 15.3% and 5.0%, respectively. In the contralateral normal thumb, the AP and RU diameters of the FPL tendon increased by 12% and 9.3%, respectively, and those in the inner space of the A1 pulley increased by 9.9% and 4.6%. During improvement in IP joint extension lag, the mismatch between the enlarged FPL tendon and the inner space of the A1 pulley was reduced by their asymmetric growth.

A Comparison of Blinded versus Ultrasound-Guided Limited-Open Trigger Finger Release Using the Yasunaga Knife.

Background: An open approach is the gold standard for trigger finger (TF) release. However, this may be associated with infection and scar tenderness. Percutaneous trigger release is an alternative, but this can sometimes result in incomplete release and digital nerve injury, even with ultrasound (US) guidance. Limited-open TF release is an intermediate technique that uses a specially designed knife via a 2-3 mm incision. The aim of this study is to compare the outcomes of blinded versus US-guided limited-open TF release using the Yasunaga knife (Medical U&A, Inc., Japan). Methods: About 138 fingers in 111 patients underwent limited-open TF release using the Yasunaga knife. Green classification was used to grade the severity of TF. Thirty-one patients had grade 3 TF and 80 patients had grade 4 TF. The TF was released in a blinded fashion in 60 patients and using US guidance in 51 patients. Outcome measures included residual triggering, contracture of the proximal interphalangeal joint, visual analog scale (VAS) for assessment of pain, Quick Disability of the Arm, Shoulder, and Hand (DASH) score, and the Patel and Moradia grading of patient satisfaction. Complications were also recorded. Results: Six patients had residual triggering in the blinded group, whereas it resolved in all patients in the US-guided group. This difference was statistically significant (p = 0.03). Patients in both groups showed significant improvement in VAS and Quick DASH score postoperatively. There were no significant differences between the two groups for these two outcomes. Patient satisfaction was graded as excellent by 20 patients and good by 30 patients in the US-guided group compared to eight excellent and 45 good in the blinded group. Conclusion: The incidence of residual triggering was lower and overall satisfaction higher in patients who underwent US-guided limited-open TF release using the Yasunaga knife. Level of Evidence: Level III (Therapeutic).

An Ultrasound-guided Percutaneous Surgical Technique for Trigger Finger Release Using a Minimally Invasive Surgical Knife.

Triggering of the finger at the A1 pulley is one of the most frequent pathologies encountered in hand surgery and a common cause of hand pain. Open release of the A1 pulley is currently still regarded as the golden-standard procedure. Nevertheless, there is an increasing interest in minimally invasive percutaneous techniques for the treatment of this condition. Current techniques range from percutaneous needle techniques without imaging, to the use of hook knives, with ultrasound guidance. Because of concerns about possible complications or incomplete releases, hand surgeons remain wary. The objective of this study was to introduce a new ultrasound-guided percutaneous surgical technique for trigger finger release, using a second-generation minimally invasive surgical knife. In this series of 78 releases, complete resolution of the symptoms was found in 98.7% of the cases. One recurrence of triggering was observed. There were no tendon injuries, infections, or neurovascular lesions recorded. This paper contains technical pearls and possible pitfalls to ensure the surgeon of a complete release and to avoid complications. A video of the technique was also included as Supplemental Digital Content (http://links.lww.com/BTH/A143). We can conclude that the procedure can be considered as safe and highly effective for the treatment of triggering at the A1 pulley.

Ultrasound-guided microinvasive trigger finger release technique using an 18-gauge needle with a blade at the tip: A prospective study.

BACKGROUND: Open surgical trigger finger release has limited success and the risk of complications; however, percutaneous techniques offer a successful alternative. There is limited understanding of the success of percutaneous trigger finger release. OBJECTIVE: To prospectively evaluate the functional outcomes of patients with Green classification Grade 2 to 4 trigger finger treated with an ultrasound-guided microinvasive trigger finger release using a special 18-gauge needle with a blade at the tip. DESIGN: Prospective, case-series study. SETTING: This study took place at an academic institution by one sports medicine physician (R.E.C.) with subspecialty training and certification in musculoskeletal ultrasound. PATIENTS: Sixty patients (79 cases) met criteria and agreed to participate in this study; 19 patients had multiple fingers treated. Average patient age was 62.8 years (SD 10.2). Average trigger finger severity diagnosis was Grade 3. INTERVENTIONS: Patients were treated with an ultrasound-guided microinvasive trigger finger release using a special 18-gauge needle with a blade at the tip. MAIN OUTCOME MEASUREMENTS: Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH), numerical rating scale (NRS), and Nirschl scores were captured preprocedure, at various time points, and at final follow-up. Changes between preprocedure and final follow-up were analyzed by paired t test (p < .05). Differences were also analyzed between finger, grade level, and gender by repeated measures analyses of variance (p < .05). RESULTS: No adverse events were documented perioperatively or postoperatively. Average follow-up time was 18.4 months (SD 4.6). At final follow-up, 100% of patients reported no recurrence of catching/locking, 97% had complete resolution of symptoms and significant improvement in QuickDASH scores, and 99% required no further treatment. All measurements showed a decrease in pain and symptoms over time. The improvements in QuickDASH score, NRS, and Nirschl scale and the resolution of mechanical symptoms were all statistically significant. CONCLUSIONS: Ultrasound-guided release using the 18-gauge needle with a blade provides significant functional improvement and full resolution of mechanical symptoms with minimal adverse events.

Percutaneous Sonographically Guided Release of Carpal Tunnel and Trigger Finger: Biomechanics, Clinical Results, Technical Developments.

The interventional use of sonography is growing fast, and percutaneous sonographically guided release is more and more used as minimally invasive treatment of carpal tunnel syndrome as well as trigger finger digit. The benefits of these procedures seem promising in clinical studies, but biomechanical studies comparing these procedures with open classical surgery are scarce. Minimally invasive releases of carpal tunnel and trigger finger could limit the phenomenon of tendon bowstringing observed after open surgery. A new model is presented to compare the biomechanical effects of open and sono-guided carpal tunnel and trigger finger releases.

Evaluation of the first annular pulley stretch effect under isometric contraction of the flexor tendon in healthy volunteers and trigger finger patients using ultrasonography.

BACKGROUND: Isometric exercises for a flexed finger have been reported to be effective for treating trigger finger as the flexor tendon widens the space under the first annular (A1) pulley towards the palmar destination during the exercise. This study aimed to evaluate the structural changes during the A1 pulley stretch in healthy volunteers and patients with trigger finger using ultrasonography. METHODS: We enrolled 25 male and 14 female patients (39 middle fingers). The thickness of the subcutaneous tissue (parameter a), A1 pulley (parameter b), and the flexor tendon (parameter c) and the distance between the dorsal surface of the flexor tendon and the palmar surface of the metacarpal head (parameter d) were measured using ultrasonography of the metacarpophalangeal joint of the middle finger flexed at 45° at rest (pattern A) and under isometric contraction of the flexor tendon against an extension force of the proximal interphalangeal joint (pattern B). RESULTS: The average differences between patterns A and B in the healthy volunteers were 0.29 mm (parameter a; P = 0.02), 0.017 mm (parameter b; P = 0.63), 0.16 (parameter c; P = 0.26), and 0.41 (parameter d; P = 0.004), and those in patients with trigger finger were 0.22 mm (parameter a; P = 0.23), 0.019 mm (parameter b; P = 0.85), 0.03 mm (parameter c; P = 0.82), and 0.78 mm (parameter d; P < 0.001). The distance between the dorsal side of the A1 pulley and the palmar surface of the metacarpal head was also significantly increased by 0.57 mm (8.2%) in healthy volunteers (P < 0.001) and 0.81 mm (11%) in patients with trigger finger (P < 0.001). CONCLUSIONS: In this study, the space under the A1 pulley was expanded under isometric contraction of the flexor tendon. These findings support the effectiveness of pulley stretch exercises for the trigger finger condition.