Anatomic Monopolar Press-fit Radial Head Arthroplasty; High Rate of Loosening at Mid-Term Follow Up

Abstract

Introduction: Radial head arthroplasty (RHA) is used for the management of unstable or unreconstructable injuries of the radial head. Our aim was to investigate clinical and radiographic outcomes in patients treated with the Acumed anatomic radial head press-fit system for trauma.

Methods: Clinical and radiographic assessment of RHAs undertaken for trauma with minimum 2-year follow-up.

Results: 16 consecutive patients, mean age 53 (21-82) and 66 month ± 27 (26-122) clinical follow-up were included. There were marked radiographic changes with 11/16 showing periprosthetic lucent lines and 13/16 showing subcollar osteolysis. Radiographic changes occurred early post-surgery. Stem loosening was associated with larger cantilever quotients (0.47 vs 0.38, p = 0.004). Overall survivability was 81.2%, with 3 RHAs removed. Clinical outcomes for the retained RHAs were acceptable with mean flexion 134°, extension deficit of 10°, pronation of 82°, and supination of 73°. Mean VAS scores were 8.5 ± 14.4, QuickDASH 13.8 ± 18.9, Mayo Elbow Performance Scores were 91.5 ± 12.5 with no poor scores.

Conclusion: Mid-term clinical functional outcomes following the Acumed anatomic RHA are acceptable in most cases. However, in view of the extensive periprosthetic lucencies and surgical removal due to loosening, patients should be cautioned when consented for implantation of the prosthesis, especially if a large collar is anticipated.

Keywords: elbow instability; radial head arthroplasty; radial head fractures.

Figure 1.

Radiographs demonstrating the zones of radiographic changes used for this study in accordance with Popovic et al. along with incidence of periprosthetic lucency by zone at radiographic follow-up. Case 5 (Final AP and lateral images at 83 month follow-up). Lucent lines surrounding the stem in all zones with a loose stem at final follow up.

Figure 2.

Radiographs demonstrating measurements of subcollar osteolysis in AP and lat views used for this study. Image demonstrates a typical stress shielding response with subcollar osteolysis with relative preservation of the endosteal cortex relative to the periosteal cortex. Case 10 Final follow up (45 months), note appearance of HO.

Figure 3.

Case 5. lateral (upper row) and AP (lower row) radiographs at 3 months, 12 months, and final follow-up (83 months). Progressive and early changes with lucent lines surrounding the stem in all zones with a loose stem at final follow-up.