Preoperative Serial Casting, Education, and Therapy for Dupuytren's Contracture

Primary Outcome Measure:

Feasibility of progressing to a full randomised controlled trial (RCT) based on predefined progression criteria across eight domains. These include participant availability (≥37 listed for fasciectomy over 9 months), eligibility rate (≥54%), consent rate among eligible participants (≥80%), and willingness to undergo randomisation (≥80%). Additional feasibility indicators include the ability to maintain blinding of assessors and surgeons throughout the study, high intervention acceptability determined via qualitative evaluation, adherence to preoperative splinting (>80%), and retention at 12-week follow-up (>80%). Safety is assessed by tracking adverse events, with progression supported if ≤20% of participants experience an adverse reaction. Thresholds for "Go," "Amend," or "Stop" decisions are defined for each domain.

Active range of movement of the affected finger(s), recorded individually at the metacarpophalangeal (MCP), proximal interphalangeal (PIP), and distal interphalangeal (DIP) joints. Measurements are obtained using a standard manual goniometer, with the participant seated, forearm supported in neutral rotation, and wrist in a neutral position.

• Flexion is defined as the angle at each joint when the participant actively attempts to flex the finger (i.e., make a fist), measured from the neutral (0°) position toward full flexion.
• Extension is defined as the angle achieved at each joint when the participant actively attempts to fully straighten the finger, measured from the neutral position toward full extension or hyperextension.

Each joint is measured and recorded separately in degrees for both maximal flexion and maximal extension. AROM is assessed at baseline, at each preoperative visit, and at 12 weeks postoperatively.

Passive range of movement (PROM) of the affected finger(s), recorded individually at the metacarpophalangeal (MCP), proximal interphalangeal (PIP), and distal interphalangeal (DIP) joints. Measurements are obtained using a standard manual goniometer, with the participant seated, forearm supported in neutral rotation, and wrist in a neutral position.

• Passive flexion is defined as the angle at each joint achieved when the examiner passively moves the finger into maximal flexion without patient effort, measured from the neutral (0°) position.
• Passive extension is defined as the angle at each joint when the examiner passively moves the finger into full extension or hyperextension, again without patient effort.

Each joint is measured and recorded separately in degrees for both maximal passive flexion and maximal passive extension. PROM is assessed at baseline, at each preoperative visit, and at 12 weeks postoperatively.

Grip strength of the affected hand is measured using a Jamar hydraulic hand dynamometer. Strength is assessed in kilograms (kg) with the participant seated, shoulder adducted and neutrally rotated, elbow flexed at 90°, forearm in neutral position, and wrist positioned between 0-30° extension and 0-15° ulnar deviation.

Participants are instructed to squeeze the dynamometer maximally for 3 seconds. Three trials are performed with a 30-second rest between attempts, and the mean value of the three trials is recorded. The second handle position on the Jamar dynamometer is used for consistency.

Grip strength is measured at baseline, at each preoperative visit, and at 12 weeks postoperatively. Measurements at baseline and 12 weeks postoperatively are performed by therapists blinded to group allocation, using standardised equipment and procedures to ensure reliability and comparability across time points.

Hand function is assessed using the Michigan Hand Questionnaire (MHQ), a validated, condition-specific, patient-reported outcome measure. The MHQ evaluates six domains: hand function, activities of daily living (ADLs), pain, work performance, aesthetics, and satisfaction with hand function. It consists of 37 items, each domain scored on a 0 to 100 scale. For all domains except pain, higher scores indicate better outcomes; in the pain domain, higher scores reflect greater pain.

Participants complete the MHQ at baseline, at each preoperative visit, and at 12 weeks postoperatively. The questionnaire is administered by a therapist, who reads each question aloud and records the participant's responses directly onto the form, following the standardised MHQ scoring protocol.

Hand function is also assessed using the Patient-Specific Functional Scale (PSFS). The PSFS is a validated, patient-reported outcome measure used to evaluate functional limitations specific to the individual's condition. Participants are asked to identify up to three activities that they are currently unable to perform or perform with difficulty due to their hand condition.

Each activity is rated on a 0 to 10 numeric rating scale, where 0 represents "unable to perform the activity" and 10 represents "able to perform the activity without any difficulty." Scores are recorded for each activity, and an average score is calculated to reflect overall functional ability.

The PSFS is administered at baseline, at each preoperative visit, and at 12 weeks postoperatively. This outcome measure captures patient-defined functional goals and changes over time, providing a highly individualised and responsive assessment of functional improvement

Barriers and facilitators to attainment of the intervention, identified through semi-structured qualitative interviews with both participants and healthcare professionals involved in the trial. Interviews are conducted to explore individual and system-level factors that influence engagement with and delivery of the intervention, including adherence, acceptability, perceived benefit, and contextual constraints.

Interviews are conducted at the end of the intervention period with a selection of participants using a topic guide developed from existing literature and trial objectives, and are audio-recorded, transcribed verbatim, and anonymised. Data are analysed thematically using framework analysis to identify recurring themes related to barriers and facilitators to intervention delivery and uptake.

The sample size estimation for a future definitive trial will be informed by the distribution and completeness of outcome data, and by recruitment, consent, adherence, and retention rates observed during the trial. These estimates will be used to model various trial design scenarios, ensuring adequate power to detect clinically meaningful differences in a future randomised controlled trial.