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

## TL;DR

A new silicone implant improves joint function and pain in patients with advanced finger osteoarthritis, with a new classification system proposed for severity assessment.

## Contribution

A novel silicone implant and a new functional-radiological classification system for PIPJ osteoarthritis are introduced and evaluated.

## Key findings

- The BRM Digitalis implant significantly improved motion, pain, and strength in patients with PIPJ osteoarthritis.
- Grade 4 patients in the PIP-Kellgren classification showed greater functional improvements compared to grade 3 patients.
- No implant fractures or infections were observed, and patient satisfaction was high.

## Abstract

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.

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 QuickDASH (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.

Statistically significant improvements were observed in total ROM, extension lag, grip strength, and QuickDASH 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 QuickDASH compared with grade 3, with no differences in satisfaction. The reintervention rate was higher in grade 4.

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.

Therapeutic IV.