Implantable Shock Absorber: Breakthrough or Hype?

The goal of this review is to discuss the current understanding of implantable shock absorbers (ISA) including mechanism of action, usage in patients, patient outcomes and the future of this technology.

Since the introduction of the ISA, it mainly has functioned as a surgical option for individuals with symptomatic medial compartment osteoarthritis who are too young, not indicated, or do not wish to proceed with arthroplasty. Biomechanically, ISA reduces peak medial compartment force by 32%. In a Food and Drug Administration (FDA) study, ISA was found superior to HTO, with significant reduction of pain and improvement of function. Survivorship and freedom to conversion to arthroplasty remains 85% at 5 years. Current randomized trial focuses on impact of continued non operative treatment of OA verses ISA. ISA is a reasonable surgical option for the treatment of medial compartment osteoarthritis without the need for disruption of the patient's native anatomy through osteotomy or arthroplasty.