Information for HSS Patients about the Exactech Recall

As shown in the diagram below, a standard knee replacement has four parts:

1. Femoral component — this is the metal piece that attaches to the thigh bone, also known as the femur.
2. Tibial tray — this is the metal piece that fits into the shin bone, also known as the tibia.
3. Patellar component — this is the piece of plastic that fits onto the kneecap, also known as the patella.
4. Tibial insert — this is a plastic insert made out of polyethylene that fits between the femoral component and tibial tray and acts as the new cushion or cartilage for the replaced knee joint.

During a recent review of its knee implant manufacturing process, Exactech learned that one of the packaging layers for the tibial insert has been out of specification and may allow oxygen from the air to diffuse into this tibial insert prior to it being implanted in a patient's knee. If a large amount of oxygen diffuses into the tibial insert while it's being stored and before it is implanted, this can lead to a process called oxidation. Oxidation can cause the tibial insert to wear out earlier than expected or to become damaged after it is implanted into the patient's body.

As shown in the diagram below, a standard ankle replacement has three parts:

1. Tibial component — this is the metal piece that attaches to the shin bone, also known as the tibia
2. Talar component — this is the metal piece that fits into the foot bone, also known as the talus
3. Polyethylene (plastic) insert — this is the plastic insert that fits between the tibial component and the talar component and acts as the new cushion or cartilage for the replaced ankle joint

During a recent review of its ankle implant manufacturing process, Exactech learned that one of the packaging layers for the plastic insert has been out of specification and may allow oxygen from the air to diffuse into this plastic insert prior to it being implanted in a patient's ankle. If a large amount of oxygen diffuses into the plastic insert while it's being stored and before it is implanted, this can lead to a process called oxidation. Oxidation can weaken the plastic insert and cause it to wear out earlier than expected or cause it to become damaged after it is implanted into the patient's body.

As shown in the diagram below, most standard hip replacements contain four critical parts:

1. Acetabular metal shell - this is the metal “socket” that goes into your native hip socket.
2. Acetabular liner (plastic / polyethylene) liner - this is the new “cushion” that replaces the damaged cartilage.
3. Femoral head - this is the new ball of your hip joint, usually made of ceramic or metal.
4. Femoral hip stem - this is the component that fits into your thigh bone and secures the new ball.

During a recent review of its hip implant manufacturing process, Exactech learned of an issue with the packaging of the plastic insert which can allow oxygen from the air into the plastic insert prior to it being implanted. If a large amount of oxygen diffuses into the plastic insert while it is being stored and before it is implanted, this can lead to a process called oxidation, which can cause the plastic to wear out earlier than expected or to become damaged after it is implanted into the patient’s body.

As shown in the diagram below, a standard shoulder replacement has four parts:

1. Glenosphere – this is the metal ball that attaches to the shoulder socket, also known as the glenoid.
2. Humeral liner – this is the plastic piece that acts as the new socket, fitting into the humeral adapter tray to allow smooth movement.
3. Humeral adapter tray - this is the metal piece that connects the humeral liner to the humeral stem.
4. Humeral stem - this is the metal piece that fits into the upper arm bone, also known as the humerus.

During a recent review of its shoulder implant manufacturing process, Exactech learned that one of the packaging layers for some Equinoxe Shoulder System glenoid components and humeral liners were packaged in non-conforming bags that were missing one of the oxygen barrier layers that protect the devices from oxidation. Non-conforming bags may allow oxygen from the air to contact the plastic (polyethylene) component of the Equinoxe Shoulder System before it is implanted into a person's body. 

Unlike the similar non-conforming packaging of Exactech polyethylene knee, ankle and hip components, the shoulder is biomechanically different than the hip, knee or ankle. Less body weight is placed on the shoulder with the types of activities that involve use of the shoulder than the hips, knees or ankles, therefore there is less stress on a shoulder implant. Exactech reviewed joint revision data in the US and in Europe, as well as peer-reviewed literature, and found revisions for polyethylene wear, dissociation, osteolysis, and fracture are rare with shoulder arthroplasty across all manufacturers. Additionally, Exactech performed oxidation and strength tests on the shoulder implants packaged in non-conforming packaging; they found low oxidation index unlikely to have a substantially negative impact on mechanical behavior.