Poor results after pyrocarbon interpositional shoulder arthroplasty
These authors aimed to describe the clinical outcomes and complications of 10 cases of pyrocarbon interposition shoulder arthroplasty (PISA) using the InSpyre shoulder prosthesis (Tornier-Wright, Bloomington, MN, USA).
The indications included patients aged < 60 years (mean age 55) with Walch type B glenoid glenohumeral osteoarthritis (7), avascular necrosis of the humeral head (AVN) (1), or secondary severe glenohumeral osteoarthritis with axillary nerve dysfunction (2).
The humeral head was dislocated and subsequently resected at the anatomical neck position. The humeral head diameter was measured using a ruler in an antero-posterior and superior-inferior orientation. The humeral metaphysis was then reamed to create a hemispherical cavity in the center of the proximal humerus. The implant was placed in the humeral cavity and the appropriate tension of the rotator cuff was maintained after passing 4 transosseous sutures. The implant diameter ranged from 36 to 46 mm.
Among these 10 patients, 5 underwent revision to reverse shoulder arthroplasty during the study period due to poor clinical outcomes. The mean time to revision surgery was 60 months. All five revised patients had Walch type B glenoid morphology at the time of the index procedure.
The remaining 5 patients who did not undergo any revision procedure had significant improvement in mean CS and SSV at a mean follow-up of 35 months.
Here is an example of a 50 year old woman with straight forward osteoarthritis.
She had a pyrocarbon arthroplasty. 18 months postoperatively, she presented with progressively worsening shoulder pain. Radiographic imaging at that time demonstrated extensive osteophyte formation of the proximal humerus. She subsequently underwent an osteophytectomy, but her shoulder pain did not improve. Thinning of the greater tuberosity was observed 4 years after the osteophytectomy. She subsequently underwent reverse shoulder arthroplasty.
Prior posts have described issues with this implant; see this link, this link, and this link.
At this point it is difficult to see that this novel technology offers any advantage over a standard total shoulder or a ream and run procedure.
