Short-Term Outcomes of Digitalis Silicone Implant for Proximal Interphalangeal Joint Osteoarthritis and a Proposed Functional-Radiological Classification

Purpose To evaluate the clinical and functional outcomes of a novel silicone implant (BRM Digitalis) for proximal interphalangeal joint (PIPJ) osteoarthritis and to propose a novel functional-radiological classification system (PIP-Kellgren) adapted from the Kellgren-Lawrence scale. Methods This retrospective longitudinal study included 33 patients with symptomatic PIPJ osteoarthritis treated using the BRM Digitalis silicone implant, with a minimum follow-up of 24 months. Subjective outcomes were assessed using the Quick DASH (Disabilities of the Arm, Shoulder, and Hand) questionnaire, visual analog scale for pain, and a seven-item Likert satisfaction score. Objective clinical and radiographic data were collected by measuring range of motion (ROM), extension lag, grip and pinch strength, pulp-to-palm distance, and evaluating implant position and integrity on final radiographs. Results Statistically significant improvements were observed in total ROM, extension lag, grip strength, and Quick DASH and visual analog scale scores. No implant fractures or infections were recorded. The average Likert satisfaction score was 3.97 of 5 (range, 3−5). Using the proposed PIP-Kellgren functional-radiological classification, grade 4 patients showed considerably greater improvements in ROM and Quick DASH compared with grade 3, with no differences in satisfaction. The reintervention rate was higher in grade 4. Conclusions The BRM Digitalis silicone implant offers consistent improvements in pain, motion, and strength for patients with advanced PIPJ osteoarthritis. The proposed PIP-Kellgren functional-radiological classification system may help stratify surgical candidates and standardize severity assessment. Type of study/Level of evidence Therapeutic IV.