Poor results after pyrocarbon interpositional shoulder arthroplasty.

Abstract

This study aimed to describe the clinical outcomes and complications of 10 cases of pyrocarbon interposition shoulder arthroplasty (PISA). The clinical and radiographic records of 10 patients who underwent PISA using the InSpyre shoulder prosthesis (Tornier-Wright) between July 2012 and March 2017 were reviewed. The mean age at surgery was 55 years. Surgical indications included patients aged <60 years with Walch type B glenoid glenohumeral osteoarthritis (n = 7), avascular necrosis (AVN) of the humeral head (n = 1), or secondary severe glenohumeral osteoarthritis with axillary nerve dysfunction (n = 2). Outcomes of interest were postoperative complications and need for revision surgery, preoperative and postoperative patient-reported outcomes (Constant score [CS] and Subjective Shoulder Value [SSV]), and range of motion. The radiographic characteristics of the implants were evaluated. Among the 10 patients, 5 underwent revision to reverse shoulder arthroplasty during the study period owing to poor clinical outcomes based on the CS and SSV. All 5 revised patients had Walch type B glenoid morphology at the time of the index procedure. The mean time to revision surgery in this subset of patients was 60 months. The remaining 5 patients who did not undergo any revision procedure had significant improvement in mean CS and SSV from 30-65 points and 32%-87%, respectively, but at a shorter duration of follow-up of 35 months. High clinical failure rate and poor results at mean 5-year follow-up were found in younger PISA patients with baseline Walch B glenohumeral osteoarthritis. We would caution against use of PISA in this challenging patient population. PISA yielded more favorable short-term outcomes in patients with humeral-sided deformity or severe secondary glenohumeral osteoarthritis with axillary nerve dysfunction; however, longevity of the implant in this population remains unclear.