Trigger Finger Release: A Technique for Ensuring Safe and Adequate Release

Summary:

Although trigger finger release is a safe and effective procedure, complications occur due to improper technique. Incomplete release of the A1 pulley risks relapse of triggering, whereas release of the A2 pulley places patients at risk for bowstringing. Complications are often the result of poor exposure, misplaced incisions, and difficulty visualizing where the A1 pulley ends and the A2 pulley begins. The transition between A1 and A2 may be distinct in some patients and obscure in others. With the A1 pulley being the most common site of triggering, the purpose of this article was to illustrate a safe, effective, and reproducible technique for A1 pulley release. The following technique relies upon the anatomical principle that the A1 pulley is contiguous with the volar plate. The technique begins with the surgeon sharply incising the A1 pulley proximally. To assess adequate release, surgeons can place the cut portion of the pulley on lateral tension while shifting the visible flexor tendons either radially or ulnarly with the goal of visualizing the “underside” (eg, synovial side) of the A1 pulley where it is contiguous with the volar plate. Because the demarcation of the borders of the A1 pulley is clearer and more distinct on the synovial side, and because the A1 pulley is contiguous with the volar plate, visualization of the adequacy of release is easily achieved. If release of the A1 pulley is inadequate, the entire volar plate will not be easily visualized. This technique ensures safe, effective, and reproducible outcomes.

Takeaways

Question: How can surgeons ensure a safe and adequate decompression during trigger finger release?

Findings: Given that the A1 pulley is anatomically contiguous with the volar plate, complete release of the A1 pulley grants visualization of the volar plate with ulnar or radial translation of the flexor tendons.

Meaning: By ensuring that the volar plate is visible after A1 pulley release, surgeons can be confident that they have performed an adequate release without risking damage to the A2 pulley.

INTRODUCTION

Trigger finger is a pathological phenomenon most common in adults 40–59 years of age and carries the potential to cause significant functional impairment.¹ Although first-line treatment includes corticosteroid injection and splinting, refractory cases are indicated for surgical intervention.² Open trigger finger release remains the current gold standard of surgical treatment for this disease, although percutaneous release has also been described.

Although this procedure is typically regarded as quick and simple, several complications can occur due to improper technique. Incomplete release of the A1 pulley risks relapse of triggering, whereas release of the A2 pulley places patients at risk for bowstringing. Bowstringing describes the phenomenon where the flexor tendon loses its constraints in the sagittal plane and pulls volarly away from the bone. This can cause decreased digital strength and an extensor lag at the metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints. If left untreated, bowstringing can lead to flexion contracture and impaired dexterity. In many of these cases, complications arise due to variations in fibro-osseous sheath anatomy from patient to patient that make it difficult to clearly visualize where the A1 pulley ends and the A2 pulley begins.^3,4

Given the frequency with which this operation is performed, surgeons would benefit from a simple technique that minimizes the risk of inadvertent compromise of the A2 pulley. The purpose of this technique guide was to illustrate a safe, effective, and reproducible technique for identifying and adequately visualizing the borders of the A1 pulley during trigger finger release.

ANATOMY

There are 5 annular pulleys present in the flexor-pulley system. Of these, the A2 and A4 pulleys are taught to be the most biomechanically important in regard to preventing bowstringing and preserving optimal tendon excursion. Recent data show that the total length of contiguous pulley release is also of clinical importance and should be taken into consideration during trigger finger release and any surgery wherein the fibro-osseous sheath needs to be accessed.⁵ The A1, A3, and A5 pulleys overlie the MCP, PIP, and distal interphalangeal joints, respectively, and originate from the volar plate.⁶

Standard procedure for trigger finger release ideally involves minimizing the amount of contiguous pulley release by incising just the A1 pulley, with care taken to protect and preserve the A2. Therefore, understanding how to readily identify the A1 pulley and differentiate it from the A2 is important for surgeons performing this procedure. Although there have been some anatomical descriptions of how far apart these 2 pulleys lie, some authors have reported significant anatomical variations in this regard, and some patients have little to no visual separation between these 2 pulleys.^3,4

The basis for the technique described in this guide is 2-fold: (1) that the “underside”/synovial side of the A1 pulley offers an unparalleled view of the distinct borders of this pulley and (2) that only the A1 pulley is anatomically contiguous with the volar plate (Fig. 1). Considering this information, the surgeon will always be able to safely release the A1 pulley in isolation.

Fig. 1.

Cross-sectional line drawing demonstrating the anatomic relationship between the volar plate and A1 pulley.

INDICATIONS/CONTRAINDICATIONS

Evaluation and diagnosis of the patient with trigger finger relies primarily on history and physical examination. The ring finger is most commonly affected, followed by the thumb, long finger, index finger, and small finger.⁷ Initial common symptoms include pain, swelling, and clicking with digital manipulation at the level of the metacarpal head.^2,7 This can develop into a locking or catching of the digit and loss of range of motion at the MCP joint and PIP joint, as well as tenderness to palpation and the development of a palpable nodule at the A1 pulley.²

Resolution of pain with a lidocaine injection into the tendon sheath can aid in making a diagnosis if needed.⁷ Temporary resolution of symptoms after a steroid injection at the A1 pulley level of the fibro-osseous sheath also confirms the diagnosis. Imaging is not necessary for diagnosis, although ultrasound of the tendon–pulley interface can be used to confirm the diagnosis.⁸

Initial management of trigger finger is conservative. There are several nonoperative options including activity modification, orthotic immobilization, hand therapy, nonsteroidal anti-inflammatory medications for pain control, and steroid injections.²

Open release of the A1 pulley is the gold standard for definitive surgical management, although there is growing literature supporting the safety and efficacy of percutaneous release as a surgical option as well.² Indication for surgical intervention is typical for trigger finger that has failed conservative management, including at least 1 corticosteroid injection.⁷ The aim of open and percutaneous release is full sectioning of the A1 pulley, with reported success rates for open release ranging from 90% to 100%.^7,9

TECHNIQUE

Per the surgeon’s preference, the case can be performed under local anesthesia only or with light sedation. The surgeon also has the option of using a tourniquet or taking advantage of the epinephrine effect afforded by the wide-awake local anesthesia no tourniquet technique.¹⁰

Setup

Patients are positioned supine with the operative extremity placed onto a hand table. Preparing and draping is performed in a standard manner. If a tourniquet is not used and a wide-awake local anesthesia no tourniquet technique preferred, it is recommended to anesthetize the patient in the preoperative holding area, allowing 20–30 minutes before incision for the epinephrine to take effect. If a tourniquet is preferred, it is inflated to the appropriate pressure based on the patient’s size and systolic blood pressure.

Superficial Exposure

A longitudinal incision is designed directly over the A1 pulley level of the affected finger fibro-osseous sheath at the level of the distal palmar flexion crease. A knife is used to incise through the skin only. Blunt dissection is performed down through the subcutaneous tissues to the A1 pulley of the fibro-osseous sheath. Great care is taken to protect the radial and ulnar neurovascular bundles at this level. A self-retaining retractor is then placed in the wound.

Deep Exposure

The technique proposed by the senior author begins with the surgeon sharply incising the visible proximal border of the A1 pulley and carrying the incision distally towards the A2 pulley. To assess adequate release, the surgeon then places lateral tension on the cut leaflet of the A1 pulley while pushing the flexor tendons either radially or ulnarly with the goal of visualizing the “underside”/synovial side of the cut pulley and its relationship with the volar plate. If the release of the A1 pulley is inadequate, the distal border of the pulley will not be visible on its synovial side, and the distal border of the volar plate will not be visible. Because the A1 pulley is contiguous with the volar plate, the release is complete once the distal border of the volar plate is visualized. Lateral traction on the cut A1 leaflets will also clearly demonstrate a sharp demarcation on the synovial side corresponding to the distal boundary of the A1 pulley. Based on the anatomical principle previously discussed, the surgeon can be assured that the A1 pulley has been adequately released in isolation and that the A2 pulley has been protected and preserved.

After releasing the A1 pulley, the digit is flexed and extended to confirm that there is no evidence of ongoing catching, locking, or triggering. If clinically significant locking persists, no further pulley should be released but rather, the cause of the persistent triggering should be identified and treated. If the triggering is occurring at the level of the A2 pulley, tendon debulking or excision of a flexor digitorum superficialis slip can be performed (the former is usually performed when the tendon appears frayed and delaminated). Please note that the senior author will accept a subtle clicking phenomenon at the end of the case if the A1 pulley has been completely released. Anecdotally, this click subsides with time once the A1 pulley has been released (Figs. 2–5).

Fig. 2.

Visualization of the volar plate when the pulley leaflet is pulled radially while the flexor tendons are retracted ulnarly. A, View of entire surgical field. B, Enhanced view of surgical anatomy. C, Labeled with boundaries of volar plate and leaflet of pulley.

Fig. 5.

Anatomic dissection demonstrating the continuity of the relationship between the A1 pulley with the volar plate. A, Global view of anatomical relationship. B, Enhanced view of anatomical relationship with the pulley leaflet being pulled radially.

Fig. 3.

View of intimate relationship between A1 pulley and volar plate visible. Freer marks distal boundary of volar plate. Distinct boundary of A1 pulley visible on synovial side of pulley. A, Global view of anatomical relationship. B, Enhanced view of anatomical relationship.

Fig. 4.

Distal edge of A1 pulley visible at distal edge of volar plate. A, View of entire surgical field. B, Enhanced view of surgical anatomy showing continuity between the A1 and volar plate.

Closure

After the procedure is complete, the wound is thoroughly irrigated and closed with 4-0 Monocryl suture. Dermabond is applied to the wound, and a light compressive dressing is placed.

EXPECTED OUTCOMES

Most patients who undergo a trigger finger release enjoy rapid symptomatic relief. Surgical wounds are expected to heal over a 3- to 4-week period during which postoperative pain abates. Some patients have postoperative stiffness and/or pain that benefits from a short course of hand therapy. The majority of patients are fully recovered by 6 weeks.

In the rare circumstance that postoperative clicking persists in the absence of clinical triggering, expectant management is warranted, as this issue usually resolves with time.

COMPLICATIONS

Although trigger finger release has a very high success rate (reported as between 90% and 100%), complications, though rare and unexpected, are real and can be difficult to treat. The current rate of complications is estimated to be between 5% and 12%, with residual stiffness/pain and refractory triggering among the most common.² Bowstringing, while less common, is another described complication. Our technique helps surgeons lower the risk of refractory triggering and bowstringing; however, residual stiffness/pain can still occur at the rate reported by modern literature.

DISCUSSION

A retrospective chart review was performed using 5 years (2020–2024) of the senior author’s practice at a single hospital. In that time, 155 trigger finger releases were performed on 127 patients. Of those patients, not 1 has had any complications requiring reoperation. Although there is no comparison cohort to reference, these clinical outcomes clearly demonstrate a balance of adequate release, avoidance of overrelease, and appropriate consistency.

One could argue that trigger finger surgery is extremely successful and low risk; complications have been documented at very low rates.² However, it is important to note that failures with this operation do occur. We argue that there is value in employing surgical techniques to take complication rates from very low to nonexistent when possible. Thus, our technique guide serves as a valuable reference for surgeons, regardless of whether they perform trigger finger releases at low or high volume.

CONCLUSIONS

Although trigger finger release is considered a highly successful procedure, the utilization of the volar plate as a visual landmark may help surgeons further limit any complications and need for additional surgery.

DISCLOSURE

The authors have no financial interest to declare in relation to the content of this article.