Adaptive proximal scaphoid implant (APSI): a systematic review of the literature

Scapholunate advanced collapse collapse (SLAC) is a challenging topic for hand surgeons. The adaptative proximal scaphoid implant (APSI) (Bioprofile-Tornier) is a pyrocarbon ovoid shaped interpositional implant, that allows adaptive mobility during motion. The aim of this systematic review is to analyze the clinical and radiological outcomes of APSI implants and possible complications. We performed a literature search combining the following key-words: "APSI", "Scaphoid's proximal pole", "implant", "scaphoid avascular necrosis", "SLAC", "SNAC", "pyrocarbon", "prosthesis", and "spacer" with no limitations for year of publication. We selected seven studies considered relevant to our systematic review. All studies described an improvement in the grip strength and the flexion extension arch compared to pre-operative values. The percentage of patients who reported progression of osteoarthritis (OA) with APSI was 17.3%, and implant's mobilization has a rate 5.1% (8/156). In conclusion the APSI implant is a reliable alternative for the treatment of SNAC wrist and SLAC wrist.