A Standardized Acupotomy Protocol For The Treatment of Tenosynovitis of Hand Flexor Tendons In Human Patients

Summary

This protocol standardizes preoperative evaluation, stepwise acupotomy, and postoperative care for treating tenosynovitis of the hand flexor tendons in human patients, aiming to improve procedural safety, enhance recovery, and reduce complications.

Abstract

Tenosynovitis of hand flexor tendons (THFT) is a high-incidence overuse injury of the hand. Its pathological essence is a dynamic imbalance between the volume of the tendon sheath and the tendon caused by fibrous connective tissue hyperplasia in the A1 pulley region, leading to mechanical entrapment and typical clinical symptoms, including palmar pain, triggering, and limited movement. Traditional conservative treatments yield suboptimal long-term efficacy, while open surgery is associated with high trauma and complication risks, creating demand for a minimally invasive therapeutic approach. Acupotomy, an integrated therapy of traditional Chinese and Western medicine, achieves minimally invasive release of the stenotic tendon sheath with minimal trauma and rapid recovery. Standardized operation is critical for its clinical application; however, detailed and standardized protocols are currently lacking. This protocol details the key steps of acupotomy for THFT, including preoperative multidimensional evaluation (history taking, physical examination, and ultrasonic assessment) with strict inclusion and exclusion criteria, standardized preoperative preparation (environment, materials, patient positioning, disinfection, and local anesthesia), the stepwise acupotomy procedure (precise insertion, targeted longitudinal release, and safe withdrawal), and comprehensive postoperative management (immediate care, functional exercise guidance, wound care, and regular follow-up assessment). The primary purpose of this protocol is to standardize acupotomy surgery for THFT, providing a structured framework for safe implementation and facilitating consistent procedural application in clinical practice.

Introduction

Tenosynovitis of hand flexor tendons (THFT), commonly known as “trigger finger,” is a frequent hand disorder caused by repeated friction and overuse of the flexor tendons and their fibrous tendon sheaths (primarily the A1 pulley) at the level of the metacarpophalangeal (MCP) joint, leading to thickening and stenosis of the tendon sheath, impeded tendon passage, and the development of aseptic inflammation¹. Epidemiological data show that the incidence is ~2%–3% and can be as high as 10% in patients with diabetes, making it an important cause of hand dysfunction and reduced working ability². The condition predominantly affects middle-aged and elderly women, manual laborers, patients with diabetes, and individuals with rheumatoid arthritis, most commonly involving the thumb, middle, and ring fingers³. Typical clinical symptoms include pain, tenderness, and swelling on the palmar aspect of the MCP joint, with palpable cord-like or nodular indurations⁴. Active flexion and extension of the affected finger are limited; in early stages, stiffness may be present, while severe cases can affect daily activities. In long-standing cases, clicking, locking, or fixation in the flexed position may occur, requiring external force for extension. Current clinical treatments include conservative methods such as immobilization, local corticosteroid injections, and medication⁵. Although these approaches can temporarily alleviate symptoms, long-term efficacy is suboptimal for some patients, with a tendency for recurrence⁶. Open surgery provides definitive treatment but is associated with surgical trauma (incision of ~1.5–2 cm), postoperative pain, risk of nerve injury, prolonged recovery time, and high cost⁷. Therefore, there is a need for a minimally invasive method that effectively releases the stenotic sheath, restores tendon gliding, minimizes trauma, accelerates recovery, and reduces the risk of complications. To address these limitations, this study presents a standardized acupotomy protocol for the treatment of THFT.

Acupotomy is a minimally invasive treatment method that integrates principles of traditional Chinese medicine with modern anatomy and biomechanics⁸. It has demonstrated advantages in orthopedics and soft tissue pain management⁹, particularly in the treatment of THFT. Acupotomy enables precise targeting of thickened and stenotic tendon sheath tissue, allowing rapid release of mechanical entrapment¹⁰. Patients often experience immediate or short-term relief, including improved finger movement and reduced pain, with consistent and reproducible outcomes¹¹. The instrument is structurally simple and cost-effective, consisting of a handle, body, and blade tip with a linear edge. The procedure requires only local anesthesia, creates a minimal wound, does not require suturing, and can be performed in an outpatient setting under appropriate aseptic conditions. The wound typically heals within 1–2 days, and patients can resume moderate functional activities shortly after treatment, with minimal disruption to daily life¹². When performed using standardized techniques, the risk of serious complications such as infection or neurovascular injury is low¹³. Systematic reviews indicate that acupotomy is more effective than acupuncture, corticosteroid injection, or oral anti-inflammatory medications in improving pain, triggering, and functional limitation¹⁴.

Modern research indicates that the therapeutic mechanism of acupotomy extends beyond simple mechanical cutting, involving a combination of needle and blade functions that enable precise minimally invasive release¹⁵. Under accurate anatomical localization, the acupotomy blade can incise the thickened and fibrotic A1 pulley ligament, which is the key step in relieving tendon entrapment¹⁶. This incision increases the tendon gliding space, immediately reducing mechanical restriction and restoring smooth tendon movement¹³. Traditional Chinese medicine theory suggests that acupotomy promotes the flow of Qi and blood, resolving local stagnation and restoring functional balance⁸. Experimental and clinical studies have shown that tendon sheath incision reduces elevated intrasheath pressure and facilitates the resolution of inflammation^17,18,19. Additionally, the mechanical stimulation produced by acupotomy may promote local tissue repair, enhance circulation, and reduce inflammatory mediators, thereby supporting healing of the tendon sheath and surrounding tissues²⁰. The overall therapeutic goal is to restore the normal biomechanical balance of the tendon–sheath system and enable smooth finger flexion and extension²¹.

This protocol provides comprehensive guidance on preoperative evaluation, preparation, the acupotomy procedure, and postoperative management for the treatment of THFT. It is particularly applicable to patients requiring a minimally invasive outpatient intervention and to clinicians seeking a standardized and reproducible technique. These standardized procedures are essential for ensuring safety, improving consistency, and enhancing clinical outcomes.

Protocol

This study was approved by the Medical Research Ethics Committee of Hubei University of Chinese Medicine (Approval No: 2025011). All patients provided written informed consent prior to participation in the study.

NOTE: The procedure should be performed by clinicians trained in hand anatomy and acupotomy techniques with prior supervised experience.

1. Perform preoperative evaluation

1. Obtain patient history
   1. Collect general patient information, including age, gender, occupation, and medical history (e.g., diabetes and rheumatoid arthritis), using face-to-face inquiry and a standardized medical record questionnaire (Supplementary File 1), which includes predefined fields for clinical symptoms, duration, frequency, pain intensity (VAS), Quinnell grading, and functional impact.
   2. Record clinical symptoms, including palmar pain, triggering, and limited movement. Document onset duration, symptom frequency, and severity (locking degree and pain level).
   3. Assess the effect of symptoms on daily activities, including eating, dressing, and writing.
   4. Assess pain intensity using the Visual Analog Scale (VAS).
   5. Grade clinical severity according to Quinnell’s grading criteria based on clinical observation.
      NOTE: The VAS ranges from 0 to 10, where 0 indicates no pain and 10 indicates severe pain.
      Quinnell’s grading system⁷ includes five levels (0–IV), corresponding to increasing severity of triggering and locking:
      grade 0, normal flexion and extension of the finger without pain;
      grade 1, normal flexion and extension with occasional pain;
      grade 2, impaired flexion and extension accompanied by a catching sensation;
      grade 3, presence of triggering that can be overcome with active motion;
      ​grade 4, fixed locking requiring passive manipulation for resolution.
2. Perform physical examination
   1. Evaluate active range of motion by instructing the patient to flex and extend the affected finger independently. Record the maximum flexion and extension angles.
   2. Evaluate passive range of motion by gently flexing and extending the affected finger. Record the angles at which triggering or locking occurs.
   3. Identify tender points by applying gradual pressure to the palmar aspect of the MCP joint. Mark the most tender location with a marker pen.
   4. Palpate along the flexor tendon from proximal to distal to identify tendon sheath thickening or nodular changes.
   5. Record the size and hardness of any palpable induration.
3. Perform ultrasound evaluation
   1. Perform transverse and longitudinal ultrasound scanning of the palmar aspect of the MCP joint using a color Doppler ultrasound system equipped with a high-frequency linear array probe (7–15 MHz).
      NOTE: Standardized imaging parameters: (1) imaging depth: 2.0–3.0 cm; (2) overall gain: 45%–60%; (3) time-gain compensation: adjust to achieve uniform gray-scale brightness from superficial to deep layers; (4) focus position: set at the level of the flexor tendon and MCP joint space; and (5) color Doppler gain: adjust to just below the level of background noise to minimize artifacts.
   2. Apply sufficient coupling gel to the palmar skin over the MCP joint. Place the probe gently and perpendicularly on the skin without excessive compression. Move the probe slowly in transverse and longitudinal planes to obtain clear sonographic images.
   3. Assess tendon sheath thickness, tendon swelling, and the presence of peritendinous synovitis (including synovial hypertrophy and effusion) under standardized gray-scale and color Doppler settings.
   4. Instruct the patient to slowly flex and extend the affected finger during scanning.
   5. Observe dynamic tendon gliding in real time. Measure tendon sliding distance using electronic calipers on the ultrasound system, defined as the linear displacement of the proximal edge of the tendon between maximal passive extension and maximal active flexion of the affected finger.
   6. Determine the extent of stenosis by identifying thickened regions of the A1 pulley.
   7. Evaluate inclusion and exclusion criteria based on clinical symptoms, physical examination, and ultrasound findings. All criteria are assessed by a trained and experienced musculoskeletal clinician.
      NOTE: Inclusion criteria (based on Diagnostic and Therapeutic Criteria of TCM Diseases):
      (1) Pain and localized tenderness at the A1 annular ligament of the MCP joint, VAS ≥4;
      (2) Triggering or limited flexion/extension, Quinnell grade ≥II;
      (3) No concurrent treatments;
      (4) Informed consent obtained.
      Exclusion criteria:
      (1) Local or systemic infection;
      (2) Coagulation disorders;
      (3) Failure of heart, brain, kidney, or other vital organs;
      (4) Uncontrolled hypertension or unstable blood glucose;
      (5) Allergy to local anesthetics;
      (6) Pregnancy or lactation.

2. Perform preoperative preparation

1. Prepare the environment
   1. Disinfect the operating room using ultraviolet (UV) air sterilization for 60 min prior to the procedure. Use a 253.7 nm germicidal UV lamp with an irradiation intensity of ≥70 µW/cm² at a distance of 1.0 m from the target surface. Ensure that the room is closed and unoccupied during irradiation, and that surfaces are free of obstructions to allow uniform exposure.
   2. Clean the treatment table and surrounding area. Cover the surface with a sterile drape.
2. Prepare materials
   1. Arrange all required materials on a clean and disinfected treatment table according to the procedural sequence (Figure 1).
      NOTE: Detailed information for all materials used in this protocol is provided in the Table of Materials.
3. Position the patient
   1. Instruct the patient to sit upright facing the treatment bed.
   2. Place the affected upper limb on the treatment table with the elbow flexed at 90°.
   3. Position the forearm on a soft pillow (height: 12 cm). Place the pillow to fully support the forearm from the elbow to the wrist, maintaining the arm in a relaxed, neutral position without tension on the soft tissues.
   4. Position the hand with the thumb abducted at 30°–45° and the palm facing upward.
4. Prepare the operator
   1. Wear surgical attire, cap, and mask. Ensure complete coverage of the mouth, nose, and hair.
   2. Perform hand hygiene according to WHO surgical hand disinfection procedures.
5. Identify the treatment site
   1. Instruct the patient to flex the affected finger to 90° at the MCP joint.
   2. Palpate the nodule on the palmar aspect of the joint.
   3. Mark the identified location using a marker pen (Figure 2A).
6. Disinfect the skin
   1. Soak cotton swabs in iodophor disinfectant.
   2. Disinfect the skin starting from the marked point and moving outward in concentric circles. Ensure that the disinfection area covers the entire hand and extends at least 15 cm proximally along the forearm from the marked point.
   3. Repeat disinfection three times, ensuring that each pass overlaps the previous area by approximately one-third.
   4. Cover the area with a sterile aperture drape, ensuring the treatment site is centered.
      CAUTION: Maintain strict aseptic technique during skin preparation to prevent infection.
7. Administer local anesthesia
   1. Draw 0.9% sodium chloride injection and 2% lidocaine hydrochloride injection into a sterile syringe at a 1:1 ratio (total volume: 5 mL).
   2. Hold the syringe with the dominant hand and stabilize the injection site with the non-dominant hand.
   3. Insert the needle at a 30° angle to the skin and advance until the needle tip reaches the subcutaneous layer superficial to the A1 pulley (approximately 2–3 mm in depth). Aspirate for 2–3 seconds to confirm the absence of blood return.
   4. Inject 0.2–0.3 mL of anesthetic solution to form a small skin wheal (0.5–1 cm in diameter).
   5. Adjust the needle to a perpendicular position and advance until the needle tip reaches the level of the A1 pulley (approximately 5–8 mm in depth).
   6. Aspirate for 2–3 s. If no blood return is observed, inject 1 mL of anesthetic solution (Figure 2B). Ensure that the total anesthetic volume does not exceed 5 mL per patient.
   7. Wait 5 min after injection.
   8. Test anesthesia using light touch with a sterile cotton swab and pinprick with a sterile needle tip.
   9. Administer an additional 0.5 mL of anesthetic if sensation persists. Reassess after 3 min.
      CAUTION: Avoid intravascular injection and excessive anesthetic dosing. Monitor for adverse reactions.
      PAUSE POINT: The procedure may be paused after anesthesia administration once adequate anesthesia is confirmed.
      NOTE: Avoid injecting anesthetic into the tendon sheath lumen, as this may interfere with intraoperative assessment of tendon gliding.

Figure 1: Materials used for acupotomy. (A) Sterile disposable syringe; (B) Lidocaine hydrochloride and sodium chloride injection; (C) Medical cotton swabs; (D) Iodophor disinfectant; (E) Sterile drape; (F) Surgical gloves; (G) Acupotomy instrument; (H) Surgical gauze dressing. Please click here to view a larger version of this figure.

Figure 2: Acupotomy procedure. (A) Surface localization of the A1 pulley region by identifying and marking the tender point on the palmar aspect of the metacarpophalangeal joint. (B) Administration of local anesthesia using a sterile syringe at the marked site. (C) Acupotomy insertion and longitudinal release of the stenotic tendon sheath. Please click here to view a larger version of this figure.

3. Perform the acupotomy procedure

1. Insert the acupotomy
   1. Wear sterile surgical gloves.
   2. Remove the acupotomy from sterile packaging.
   3. Inspect the blade tip under natural light to ensure it is sharp, intact, and free of damage. Replace the instrument if defects are present.
   4. Apply pressure with the non-dominant thumb 1 cm proximal to the marked nodule, sufficient to stabilize the tendon without causing patient discomfort or tissue blanching.
   5. Tension the skin distally using the index finger to create a flat surface.
   6. Hold the acupotomy with the dominant hand.
   7. Align the blade parallel to the flexor tendon and perpendicular to the skin.
   8. Insert the acupotomy through the skin and advance through the epidermis and dermis.
      CAUTION: Maintain alignment with the tendon axis during insertion to avoid injury to the flexor tendon, digital nerves, and blood vessels.
2. Release the tendon sheath
   1. Incline the acupotomy toward the proximal end of the finger until it is parallel to the skin surface.
   2. Advance the acupotomy until resistance from the tendon sheath is felt.
   3. Continue advancing while performing controlled longitudinal cutting.
   4. Stop advancing when a loss-of-resistance sensation is detected, confirmed by improved tendon gliding and smooth, unrestricted flexion–extension of the finger (Figure 2C).
   5. Confirm release by assessing reduction of resistance under the acupotomy.
   6. Instruct the patient to actively flex and extend the finger 5–10 times.
   7. Observe whether tenderness, triggering, and locking are resolved.
   8. Confirm smooth and unrestricted finger movement.
   9. Perform 1–2 additional longitudinal cuts within an amplitude range of 1–2 mm if minor triggering persists. Maintain blade alignment parallel to the tendon axis.
   10. Stop the procedure once adequate release is achieved.
       CAUTION: Avoid excessive cutting or deviation from the tendon axis, as this may result in tendon rupture or neurovascular injury.
       NOTE: During release of the fibrous sheath, avoid large-amplitude transverse or rotational movements. Maintain alignment of the acupotomy with the tendon to prevent tendon injury.
3. Withdraw the acupotomy
   1. Withdraw the acupotomy slowly along the insertion path.
   2. Apply pressure to the insertion site with sterile gauze for 3–5 min until visible bleeding ceases and slight local skin blanching is observed, indicating adequate hemostasis.
   3. Maintain pressure within a 1 cm radius around the insertion site during compression.
   4. Disinfect the insertion site using iodophor.
   5. Apply a sterile adhesive dressing after confirming the absence of active bleeding.
      CAUTION: Monitor for bleeding or hematoma formation. Apply sustained pressure if bleeding persists.

4. Provide postoperative management

1. Provide immediate care
   1. Apply moderate compression bandaging to the palm and affected finger using an elastic bandage, ensuring uniform pressure that provides mild compression without impairing tissue perfusion or causing patient discomfort.
   2. Assess fingertip blood circulation by evaluating finger color, skin temperature, and capillary refill time. Assess capillary refill by pressing the fingertip firmly for 2 s and observing recovery of color within 2 s.
   3. Assess sensory function using light touch. Confirm absence of numbness.
      CAUTION: Ensure that bandaging does not impair circulation. Loosen the bandage if signs of ischemia are observed.
2. Guide activity
   1. Instruct the patient to perform gentle finger flexion and extension exercises.
   2. Gradually increase the range of motion and frequency of exercises. Perform active finger flexion and extension exercises 3–4 times daily, with 10–15 repetitions per session, to promote circulation and prevent tendon adhesion.
      NOTE: Avoid excessive force or vigorous movements during early rehabilitation.
3. Manage the wound
   1. Keep the wound clean and dry. Avoid water exposure and contamination.
   2. Replace the sterile adhesive dressing daily or when it becomes wet, contaminated, or loosened.
   3. Monitor for signs of redness, swelling, exudation, or wound dehiscence.
   4. Seek medical attention if signs of infection occur, including redness, swelling, heat, pain, or purulent discharge.
   5. Maintain a light diet. Avoid spicy or irritating foods.
   6. Avoid smoking and limit alcohol consumption. Maintain regular sleep patterns to support recovery.
      CAUTION: Monitor for signs of infection and delayed wound healing. Initiate medical evaluation if symptoms worsen.
4. Perform postoperative assessment
   1. Schedule in-person follow-up evaluations at 1 week, 2 weeks, and 1 month postoperatively.
   2. Assess treatment outcomes using VAS and Quinnell grading at 1 month.
   3. Perform ultrasound re-examination if recurrent triggering or pain (VAS score ≥ 3) is observed.
      PAUSE POINT: Follow-up assessments may be conducted at scheduled outpatient visits.

5. Perform statistical analysis

1. Collect VAS scores and Quinnell’s grades from patients before treatment and at 1 month postoperatively using in-person visits or telephone follow-up. For telephone follow-up, use a standardized structured questionnaire (Supplementary File 1) to assess pain (VAS) and finger function (Quinnell grading).
2. Perform a paired-sample t-test to evaluate statistical significance. Define statistical significance as P < 0.05.
3. Ensure that data quantification is performed by assistants blinded to the experimental conditions by masking patient identifiers and pre- and post-treatment labels prior to analysis, with all group and time-point information concealed throughout the measurement process.
4. Express data as mean ± standard deviation.
   NOTE: This study is a standardized protocol study rather than a confirmatory clinical trial; therefore, no formal sample size calculation was performed. A total of 16 patients were enrolled to preliminarily verify the feasibility, safety, and operational procedures of the protocol.

Results

Sixteen patients with THFT were treated using the protocol, and no adverse events were observed. VAS scores and Quinnell’s grades showed improvement following the procedure. These findings indicate that the protocol can be implemented safely and provides a structured approach for performing the procedure, with consistent short-term clinical outcomes observed.

Pain outcome (VAS scores):

The mean preoperative VAS score was 6.31 ± 1.01, which decreased to 0.81 ± 1.10 a...

Discussion

This study presents a standardized protocol for acupotomy in the treatment of THFT and demonstrates that the procedure can be performed safely, with favorable short-term clinical outcomes. Improvements in pain and functional mobility were observed following the procedure, suggesting that the protocol is feasible under the conditions described. THFT has a high incidence in the population²², being particularly common among individuals who frequently use their hands for fine motor tasks. Patients oft...

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
0.8 mm × 50 mm disposable sterile acupotomy	Jiangxi Laozongyi Medical Devices Company Limited	N/A	For acupotomy operation
0.9% sodium chloride injection (10 mL)	China Otsuka Pharmaceutical Company Limited	DB01-1.0701	For anesthetic dilution
2% lidocaine hydrochloride injection	Hubei Tianyao Pharmaceutical Company Limited by Shares	D32411071	For local anesthesia
Disposable sterile aperture drape (50 cm × 60 cm)	Henan Kang'erjian Medical Technology Company Limited	N/A	For sterile field isolation
Iodophor disinfectant (0.5%)	Wuhan Xuehuan Medical Disinfection Supplies Company Limited	N/A	For preoperative skin antisepsis
Medical cotton swabs (20 cm)	Henan Yubei Medical Supplies Company Limited	N/A	For skin disinfection and cleaning
Sterile adhesive dressing (10 cm × 10 cm)	Qingdao Hainuo Biological Engineering Company Limited	HN-001	For wound coverage
Sterile disposable syringe (5 mL)	Jiangsu Suyun Medical Devices Company Limited	N/A	For local anesthetic and saline injection
Sterile surgical gloves	Medicom	1144D	For aseptic operation
Surgical gauze dressing (8-layer, 7 cm × 9 cm)	Qingdao Ainuan Medical Technology Company Limited	C120	For hemostasis and wound care
Ultrasound coupling gel	Wuhan Coupling Medical Technology Company Limited	XOH-WJJ	For ultrasound imaging
Ultrasound system (color Doppler)	Mindray Medical International Limited	Model: Resona R9Q	For ultrasound evaluation