Ergonomic Redesign of Pill Jars: Reducing Hand Strain and Enhancing Usability for the Older Adults Suffering from Osteoarthritis

Older adults frequently find standard pill-jar designs challenging, leading to muscle and tendon strain, frustration, and even missed doses. This investigation identifies the precise hand-strain points when opening two different jar styles. Motion analysis shows that gripping and twisting actions place the greatest load on the thumb’s base and tip—overworking the flexor pollicis longus—while inflamed knuckles that cannot fully curl burden the flexor digitorum profundus. Repeated gripping also exhausts the index and middle fingers, stressing both the extensor and flexor digitorum profundus tendons. A Rapid Upper Limb Assessment (RULA) comparing the old and new jars yielded RULA scores of 5 and 2, respectively, reflecting significant improvements in thumb, wrist, and palm posture and reduced strain. Among the different regions of the fingers subjected to strain during the operation of common pill jars, the study identified two areas experiencing particularly high levels of stress. This increased strain poses challenges for elderly individuals with osteoarthritis, making it difficult for them to open containers and manage their daily medications. Findings indicate that repeated loading is concentrated at the dorsal digital expansion—the extensor hood, a specialized connective tissue on the back of the fingers where multiple muscle tendons converge. This suggests the fingers are engaged in complex fine motor tasks, including extension, stabilization, and precise adjustments. Furthermore, the flexor digitorum profundus—a deep muscle responsible for bending the fingers at the tips—is also under significant strain, pointing to intense gripping, pulling, or sustained finger flexion likely performed with force or over extended periods. These findings underscore the necessity for pill-jar redesigns that accommodate age-related limitations: intuitive opening mechanisms, ergonomic shapes that alleviate strain, and high-friction, non-slippery materials. Since swollen knuckles impede finger flexion, minimizing required pinch force is essential to ensure effortless, strain-free operation.