This is a prospective, multicenter, randomized controlled trial comparing clinical and patient-reported outcomes between longitudinal and transverse incisions for open A1 pulley release in the treatment of idiopathic trigger finger (stenosing tenosynovitis of the fingers, excluding the thumb). Stenosing tenosynovitis of the flexor tendon, commonly known as trigger finger, is a frequent hand condition with a lifetime incidence of approximately 2.6%. It results from inflammation and a size mismatch between the flexor tendon and the first annular (A1) pulley, leading to painful catching, clicking, or locking during finger flexion and extension. When conservative measures such as splinting and corticosteroid injections fail, surgical release of the A1 pulley is indicated. Although A1 pulley release is one of the most commonly performed hand procedures and is generally considered safe and effective, reported complication rates range from 6% to 36% and include wound-healing issues, persistent or recurrent triggering, infection, wound dehiscence, and painful scar formation. Patient dissatisfaction is most often related to scar tenderness, irritation, and cosmetic concerns that can limit tendon gliding and hand function. Two incision techniques are commonly used: longitudinal (along the axis of the finger) and transverse/oblique (within the distal palmar crease). Proponents of the longitudinal incision emphasize improved visualization and extensibility, while proponents of the transverse incision highlight superior cosmesis and faster healing. Despite the frequency of this procedure, high-quality evidence comparing these approaches remains limited. This trial was designed to address this knowledge gap in a setting of clinical equipoise, where surgeons at the participating centers routinely use both techniques. The primary objective is to compare post-operative upper-extremity function, as measured by the PROMIS Upper Extremity (UE) score at approximately 6 weeks, between the longitudinal and transverse incision groups. Secondary objectives include comparing post-operative pain (Numeric Pain Scale), time to return to work, time to pain-free finger extension (tabletop test), additional PROMIS domains (Physical Function, Pain Interference, and Depression), scar outcomes using validated scales (POSAS, SCAR-Q, and 0-10 global satisfaction), and complication rates (wound dehiscence, infection, return to OR, and revision surgery). This investigator-initiated, multicenter, 1:1 randomized controlled trial will enroll approximately 200 participants across participating sites, with Washington University School of Medicine/Barnes-Jewish Hospital system serving as the lead site and the University of Chicago as a second site. Block randomization, stratified by site, will be performed immediately after consent using a secure web-based randomization system. Eligible participants are adults ≥18 years old with a diagnosis of trigger finger (fingers only) who provide written informed consent; exclusion criteria include revision surgery, prior surgery on the affected finger, or refusal of consent. The intervention consists of standard open A1 pulley release performed through either a longitudinal incision or a transverse incision placed in the distal palmar crease, with all other aspects of surgical technique and post-operative care standardized. Intra-operative data collected will include the need for FDS excision and any incision extension. The primary outcome is the PROMIS Upper Extremity score at \~6 weeks post-operatively. Secondary outcomes include Numeric Pain Scale scores (days 1-3, \~2 weeks, \~6 weeks, and \~12 weeks), days to return to work, days to pain-free finger extension (tabletop test), PROMIS Physical Function, Pain Interference, and Depression scores, scar metrics (POSAS, SCAR-Q, and 0-10 global satisfaction) at \~2, \~6, and \~12 weeks, and complication rates. Study procedures include pre-operative collection of demographics, medical history (including diabetes, depression/anxiety, and chronic opioid use), trigger finger details, and baseline PROMIS scores. Post-operatively, pain reports will be collected on days 1-3, with in-person or virtual assessments at \~2 weeks, \~6 weeks (primary endpoint), and \~12 weeks; scar photographs will be obtained during in-person visits. All data will be entered into a Washington University REDCap instance. Continuous outcomes will be compared using t-tests or Mann-Whitney U tests, while categorical outcomes will use chi-square or Fisher's exact tests; mixed-effects models will account for repeated measures and site effects. The sample size was calculated to detect a 4-point difference in PROMIS UE score (minimal clinically important difference) with 80% power and α=0.05, accounting for the reported standard deviation. The results of this trial will provide evidence-based guidance on optimal incision selection to improve functional recovery, reduce pain, optimize scar healing, and enhance patient satisfaction after A1 pulley release.
