The integration of advanced textile materials is crucial to enhance the quality of healthcare solutions. Three-dimensional (3D) knitted spacer fabrics (KSFs) have emerged as a revolutionary class of medical textiles distinguished by their unique ability to provide high breathability, moisture management, and customizable structural properties. This comprehensive review systematically examined the multifaceted applications of 3D KSFs in the healthcare sector. It begins with an overview of various design and manufacturing techniques, including warp and weft knitting processes, that facilitate the production of innovative fabrics. The review then details the distinct structural and functional features of 3D KSFs, emphasizing their cushioning effects, porosity, and adaptability, which enhance their effectiveness in the medical context. Subsequent sections explore diverse applications, including wound care, where their moisture-wicking capabilities promote healing, pressure ulcer prevention, leveraging their ability to evenly distribute pressure, and orthopedic supports, which benefit from their comfort and supportive characteristics. This paper also discusses the potential of 3D KSFs in scaffold development for tissue engineering, as well as their use in assistive devices for enhanced patient mobility. Emerging trends, such as the incorporation of smart technologies for real-time monitoring and commitment to sustainability through washable and reusable designs, are critically analyzed. In turn, this review provides an in-depth resource for healthcare professionals, textile researchers, and product developers, highlighting the transformative potential of 3D KSFs for advancing healthcare solutions and improving patient outcomes.