Radiographic findings after radial head replacement

Radial head arthroplasty (RHA) has become the preferred treatment for displaced radial head and neck fractures that cannot be fixed. While good short-term results are reported, mid- to long-term radiographic findings such as loosening, stress shielding, and radiocapitellar arthritis are not uncommon. The aim of this study was to analyze and quantify radiographic findings after primary RHA. We hypothesized high rates of radiographic changes could be appreciated at mid-term follow-up.

Patients at a single institution who underwent RHA between 2006 and 2019 with at least six months of radiographic follow-up were included. Associated injuries, fracture pattern, implant design, radiolucency, stress shielding, radiocapitellar arthritis, and heterotopic ossification were evaluated. Radiographic reviews were performed independently by two fellowship-trained orthopedic surgeons. Regression analysis was used to assess the relationship between demographics, clinical characteristics, and radiographic findings and reoperation.

Sixty-three elbows amongst 62 patients with a mean age of 47 (range 15-83) met inclusion criteria, with an average follow-up of 748.8 days (range 230-4554 days). At mid-term follow-up, 82.5% of patients had at least one radiographic finding, most of which were mild; stress shielding was present in 58.7% and radiolucency in 27.0%. In regression analysis, implant type was not associated with an increased odds for radial head specific reoperation. Age, follow-up duration, fracture pattern, and associated ligamentous injuries were not associated with SS, arthritis, HO, or radiolucency. Male gender was associated with a lower degree of radiocapitellar arthritis (estimate - 0.40; 95% CI - 0.72 to - 0.08), as was the use of bipolar implants (estimate - 0.6; 95% CI - 1.11 to - 0.09).

Radiographic changes are frequently observed by mid-term follow-up after RHA, although most are mild and do not necessarily indicate clinical failure. Male gender and the use of bipolar implants may be protective against radiographic radiocapitellar arthritis. However, the clinical implications of these radiographic findings remain to be determined.

III.

Prognostic.