Tuesday, October 16, 2018

Shoulder joint replacement failure - a bigger problem than previously recognized.

Analysis of 4063 complications of shoulder arthroplasty reported to the US Food and Drug Administration from 2012 to 2016

Most of the literature on shoulder arthroplasty failure comes from high-volume centers. These reports tend to exclude the experience of community orthopedic surgeons, who perform most of the shoulder joint replacements.

These authors analyzed the failure reports mandated by the US Food and Drug Administration for all hospitals. Each reported event from 2012 to 2016 was characterized by implant, failure mode, and year of surgery.

For the 1673 anatomic arthroplasties, the most common failure modes were glenoid component failure (20.4%), rotator cuff/subscapularis tear (15.4%), pain/stiffness (12.9%), dislocation/instability (11.8%), infection (9%), and humeral component loosening (5.1%). 

For anatomic shoulder arthroplasties, the failure modes have not appreciably changed over recent years

For the 2390 reverse arthroplasties, the most common failure modes were dislocation/instability (32%), infection (13.8%), glenosphere-baseplate dissociation (12.2%), failed/loosened baseplate (10.4%), humeral component dissociation/tray fracture (5.5%), difficulty inserting the baseplate (4.8%), and difficulty inserting the glenosphere (4.2%). 

For reverse shoulder arthroplasties, the failure modes have not appreciably changed over recent years

Although the percentage distribution among the different failure modes was relatively consistent over the years of this study, the percentage distribution of these failure modes differed substantially among different implant manufacturers.

The authors conclude that the Food and Drug Administration database reveals modes of shoulder arthroplasty failurethat are not emphasized in the published literature, such as rotator cuff tear, infection, and postoperative pain/stiffness for anatomic total shoulder arthroplasty and implant dissociation and baseplate failure for reverse shoulder arthroplasty. Knowledge of these failure modes may help inform surgical technique and implant design in ways that will lower the risk of implant failure in the future.

Comment: In addition to the high numbers of failures reported to the FDA, the authors note that the rate of recall of new devices is also high, possibly due to unanticipated modes of failure that become evident only after periods of use. 

It is important to recognize that the device failures reported to the FDA under represents the number of actual arthroplasty device failures because there is no method for assuring that each device failure is reported.

The high rate of failure of new devices suggests caution before the adoption of new implants and instruments. Surgeons should recognize that 510(k) clearance requires only that the manufacturer demonstrate that the new device is "substantially equivalent" to a previously marketed device (even if the the previously marketed device has been recalled). This is in marked contrast to the rigorous premarket approval process the FDA requires for new drugs - the PMA process requires demonstration of both safety and efficacy.

We have a new set of shoulder youtubes about the shoulder, check them out at this link.

Be sure to visit "Ream and Run - the state of the art"  regarding this radically conservative approach to shoulder arthritis at this link and this link

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You may be interested in some of our most visited web pages   arthritis, total shoulder, ream and runreverse total shoulderCTA arthroplasty, and rotator cuff surgery as well as the 'ream and run essentials'