Long-term survival of the glenoid components in total shoulder replacement for arthritis.

PURPOSE: Aseptic glenoid component loosening remains a common problem in total shoulder arthroplasty (TSA). This study presents long-term prospective follow-up after implantation of a glenoid component using the "cancellous compaction technique" and its effect on clinical outcome and presence and progression of radiolucent lines (RLLs).
METHOD: Thirty-nine TSAs were performed for primary osteoarthritis by one surgeon using the same technique. For the glenoid side, a keeled, polyethylene, convex-backed component was implanted using the "cancellous compaction technique" consisting of minimal reaming, compaction bone grafting of the glenoid and minimal addition of cement. Postoperative clinical outcome was analysed using Constant scores and patient's subjective evaluation. Independent observers evaluated postoperative X-rays for radiolucent lines (RLL) around the base plate and keel.
RESULTS: At an average follow-up of 8.5 years (range 4.7-12.5), the Constant score improved from 33.5 to 73.0 points (P < 0.0001). Active anterior elevation improved from an average 95 ° to 140° (P < 0.0001), and active external rotation improved from 20° to 45° (P < 0.0001). Pain score improved from 3.1 to 13.6 (P < 0.0001). Radiologically, the RLL score increased from 1.09 (range, 0-3) postoperative to 5.7 (range, 0-18) (P < 0.0001) at final follow-up. The occurrence of definite radiological glenoid loosening was 15.5 %. Constant scores deteriorated with the progression of RLLs (P = 0.006). The rate of revision surgery for glenoid loosening was 2.5 %.
CONCLUSIONS: This study showed highly satisfactory clinical outcomes and low rates of revision for glenoid loosening using a bone-saving compaction technique for implantation of an all-polyethylene glenoid component.