Total shoulder replacement using a bone ingrowth central peg polyethylene glenoid component: a prospective clinical and computed tomography study with short- to mid-term follow-up.

AIM OF THE STUDY: To assess the clinical and computed tomography (CT) outcomes of shoulder replacement with a novel bone ingrowth all-polyethylene glenoid component (APGC).

METHODS

Twenty-eight patients (30 shoulders) with osteoarthritis, mean age 62.3 years (range, 45-75), were implanted with the novel component between 2011 and 2013. Patients were evaluated by active range of motion (ROM), Constant-Murley score (CMS), simple shoulder test (SST), X-rays, and multidetector CT at two months and at a mean follow-up of 31 months (range, 24-39). Early and late follow-up CT scans were available for 21/30 shoulders.

RESULTS

Median ROM increased from 105 to 160° for anterior elevation, from 100 to 160° for lateral elevation, from 20 to 40° for external rotation, and from 2 to 10 points for internal rotation (all p < 0.001). CMS rose from 30 to 80.5 points and SST from 2.5 to 11 (both p < 0.0001). None of the glenoid components migrated. Progressive radiolucency was seen in 28/30 shoulders. There was a strong correlation between greater bone ingrowth (median Arnold score: 7) and lower radiolucency score (median Yian score: 2) at the last follow-up (p < 0.001). Osteolysis around the central peg was seen in two shoulders. There was no correlation between clinical scores and CT findings (p >0.05).

DISCUSSION: The partially cemented glenoid component for TSR assessed in this study resulted in satisfactory shoulder function at an early follow-up. The glenoid prosthesis was stable, with few radiolucent lines and good central peg bone ingrowth.

CONCLUSIONS

The satisfactory bone ingrowth documented on CT is encouraging and supports the use of the new prosthesis. Long-term follow-up studies can confirm if this device represents a rational alternative to fully cemented polyethylene glenoids.