MAUDE Adverse Event Report: EXACTECH, INC. EQUINOXE REVERSE GLENOSPHERE LOCKING SCREW

Catalog Number 320-15-05

Device Problems Failure To Adhere Or Bond (1031); Fracture (1260); Migration (4003)

Patient Problems Joint Disorder (2373); No Code Available (3191)

Event Date 11/03/2017

Event Type  Injury  

Manufacturer Narrative

Pending device return and evaluation.

Event Description

Pending revision due to loosening.

Manufacturer Narrative

Pending evaluation.

Event Description

Revision due to loosening.Intraoperatively, a broken glenosphere locking screw was found.

Manufacturer Narrative

The complaint products were received for analysis.The screw was confirmed to be broken.Catalog # 320-01-38 sn# (b)(4).Visual inspection (7x-10x) shows fine scratches consistent with tool marks during revision surgery.There is a large scratch that is consistent with contacting another hard surface, such as a displaced locking screw fragment or glenoid plate.The apical hole shows deformation consistent with threading the locking screw off-axis into the glenoid base-plate creating interference between the locking screw and the trailing edge of the apical hole.Catalog # 320-15-05 sn# (b)(4).Visual inspection (7x-10x) and with calipers show that the length is 0.8845 inches (normal screw length is 0.88), the entire screw is accounted for.Burnishing at the neck and head appear consistent with rubbing against hard metal surfaces, such as the interior of the apical hole of the glenosphere during insertion and possible after disassociation while implanted.There appears to be cross-threading of the screw off-axis into the glenoid base plate.The damaged threads appear to occur up to approximately 0.18 -0.2" from the tip.Both fracture surfaces of the locking screw appear consistent with crack initiation propagation, and ultimate fracture under a load greater than the yield strength of the material.The protrusion of the screw illustrates that the fracture surface of the screw was not at the interface with either the glenosphere or the glenoid plate which appears consistent with the glenosphere not being completely seated to the glenoid plate where those surfaces would normally be coincident.The fracture occurred approximately at the plane of the last proximal thread which is likely associated with the stress concentration that would occur at the change in minor diameter.The interior of the articular surface of the humeral liner has small scratches consistent with rubbing against the glenosphere during normal implantation.The anterior and posterior aspect of the articular geometry is worn and rough and one of the liner's lips is ragged which appears consistent with rubbing against a non-articular surface of the glenosphere, the edge of the glenoid plate, or possibly the disassociated portion of the locking screw.Post-operative x-rays were reviewed and a computer overlay was conducted, this view has the appearance that the glenosphere was not completely seated against the glenoid plate.The frequency of occurrence ranking is very low; therefore, this event does not appear to be design related.There are no other complaint reports involving these manufacturing lots, therefore, this event does not appear to be manufacturing related.User-related issues are addressed in the most-likely cause statement.Appropriate seating of the glenosphere is addressed in the operative technique.The screw breakage reported was likely the result of misaligned seating of the glenosphere on the glenoid baseplate in the initial surgery, which allowed for the glenosphere locking screw to only achieve a few threads of engagement with the glenosphere baseplate.This would create a bending movement on the glenosphere locking screw as the shear force would be transmitted directly through the locking screw rather than through the glenosphere/baseplate construct.In review of the labeling and op techs/ifus - information is identified about the use of the shoulder system to ensure proper seating and sizing by inserting the glenoid and how to appropriately and properly insert the screws and devices.The big lip of the poly should be inferior with system it can also be helpful to place the torque defining screw through the humeral tray before connecting it to the stem so that the threads engage more easily.It is a known complication that a patient's age, weight, activity level, and/or trauma would cause the surgeon to expect early failure of the system.Surgical interventions and revisions are a known complication of joint replacement devices.The surgeon must be fully knowledgeable about the surgical technique and trained according to the proper use of the system instrumentation and implants.Device specific risks include excessive wear of the implant components secondary to impingement of components or damage of articular surfaces.This device is used for treatment, not diagnosis.

Event Description

It was reported from germany that a patient experienced a shoulder revision surgery.The patient presented to the doctor on (b)(6) 2017 with "clicking" in his shoulder without pain.X-ray showed parts of a screw in the joint.During the revision surgery, a broken glenosphere locking screw was found.No parts of the screw were left in the glenosphere, it had completely disengaged.The revision was completed successfully and the patient is reported as "doing good" and that the shoulder is functioning as intended.There is no additional information provided.This is one of three products involved with the reported event and the associated manufacturer report numbers are 1038671-2017-00804 and 1038671-2017-00824.

• Brand Name: EQUINOXE REVERSE GLENOSPHERE LOCKING SCREW
• Type of Device: GLENOSPHERE LOCKING SCREW
• Manufacturer (Section D): EXACTECH, INC.; 2320 nw 66th court; gainesville FL 32653
• MDR Report Key: 7003562
• MDR Text Key: 91108890
• Report Number: 1038671-2017-00805
• Device Sequence Number: 1
• Product Code: KWT
• Combination Product (y/n): N
• PMA/PMN Number: K063569
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: company representative,foreig
• Type of Report: Initial,Followup,Followup
• Report Date: 03/12/2019

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Date FDA Received: 11/06/2017
• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: No
• Device Operator: Physician
• Device Expiration Date: 08/18/2020
• Device Catalogue Number: 320-15-05
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 11/13/2017
• Was the Report Sent to FDA?: No
• Date Manufacturer Received: 03/11/2019
• Is This a Reprocessed and Reused Single-Use Device?: No
• Patient Sequence Number: 1
• Patient Outcome(s): Other; Required Intervention
• Patient Age: 76 YR