Small but powerful: The relative motion orthosis (RMO)

The Relative Motion Orthosis (RMO) is a small multiple-finger-based device that has proven to be an extremely beneficial orthotic intervention in hand rehabilitation (Hirth et al., 2016). This orthosis is used for a variety of clinical conditions, including post-surgical repair of extensor tendons, arthritis management, proximal interphalangeal (PIP) joint deformities (boutonniere deformity and/or swan neck deformity), and even for exercising a stiff finger (Feehan et al., 2023; Hirth et al., 2016; Howell et al., 2023; Howell et al., 2005; Merritt, 2023; Newington et al., 2023; Odewahn et al., 2023; Wajon & Howell, 2022; Yates et al., 2023). The RMO typically holds one finger in relatively more metacarpal-phalangeal (MCP) joint extension or flexion than adjacent MCP joints; relative motion extension (RME) refers to the MCP joint of the involved finger held in more extension than adjacent fingers, while relative motion flexion (RMF) refers to the MCP joint of the involved finger held in more flexion (Wajon & Howell, 2022). The RMO can be formed around three or four fingers, provided that the intended position of the target MCP joint is maintained (Schwartz, 2023).