Saturday, February 13, 2016

Total shoulder - isn't an all poly glenoid good enough? does glenoid type matter?

Radiographic and clinical outcomes of total shoulder arthroplasty with an all-polyethylene pegged bone ingrowth glenoid component: prospective short- to medium-term follow-up.

These authors reviewed 80 total shoulders using an all polyethylene glenoid component.  The glenoid was reamed minimally to preserve subchondral bone, which was given priority above correcting retroversion.

1 of 80 shoulders was revised for aseptic glenoid loosening.  81.6% had a radiolucency grade of 0 or 1. Nearly 90% had a glenoid seating grade of A or B. Grade 2 or 3 bone around the central peg was seen in 88.2%. 

No statistical association existed between Walch glenoid types and radiolucency grades, bone grades around the central peg, perfect radiolucency grade, seating grade, and grade 3 bone around the central peg.

Comment: We previously posted on this article here, emphasizing the importance of register (see link).

We'd like to add a few additional thoughts. These authors use a technique similar to the one used in our practice (see link).  No patient-specific instrumentation or complex 3D reconstructions were used. The glenoid was reamed conservatively to a single concavity without emphasizing a change in version. 

Using the all poly glenoid after careful glenoid preparation with minimal reaming yields consistently better results than those achieved with metal backed components (see link). The DePuy and the Tornier versions of the modern all-poly glenoids are shown below. Other relevant links are here and here

The quality of fixation and the bone ingrowth into the pegs is substantial as shown in some of our cases below.

Against this background, we wonder whether more complex components, such as the one shown below and discussed here, provide additional value.