Adaptive Proximal Scaphoid Implant: Indications and Long-Term Results

Objective  This study aims to define the indications of APSI and to evaluate the long-term results. Patients and Methods  This is a monocentric study including patients that underwent an arthroplasty of the scaphoid proximal pole using an APSI between 1994 and 2010. Patients were assessed using autoquestionnaires and measuring ranges of motion, key pinch, and grip strength. X-ray views of the wrist were done to control the mobility of the implant and the evolution of the carpal collapse, if present. Results  There were 19 patients included with a mean follow-up of 11 years. The mean range of motion was 106 degrees (65% of contralateral side) in flexion-extension and 33 degrees (78% of contralateral side) in radialulnar deviation. The mean grip strength was 72% of the contralateral side. The mean Mayo wrist score was 69/100, the mean QuickDASH 26/100, and the mean patient-rated wrist evaluation (PRWE) 25/100. After 10 years, evolution to osteoarthritis was noted in 32% of the patients. This was associated with a decrease of the carpal height. More specifically, capito-lunate osteoarthritis was noted after 10 years and two out of three patients were concerned after 20 years of follow-up. No osteoarthritis was diagnosed at the radiolunate articulation. Conclusion  APSI is a treatment option that enables patients with scaphoid nonunion advanced collapse (SNAC), scapholunate advanced collapse (SLAC) I or II to preserve the strength and mobility with good functional results. But this arthroplasty does not prevent natural evolution to a carpal collapse after a follow-up of 20 years which is clinically well tolerated.