[Mid-term complications of the monopolar, modular radial head prosthesis]

The objective of this study is to assess the type, frequency and severity of complications after the implantation of the modular monopolar radial head prosthesis.

Forty-seven patients with 48 radial head prostheses implanted between 2009 and 2017 were reviewed retrospectively. Patients were evaluated clinical and radiographically for a mean follow-up of 43.55 months (range: 12-89).

The same type of prosthesis was implanted in every patient (Ascension Modular Radial Head). The average score in the Mayo Elbow Performance Score was 88.29 ± 9.9 points. During the follow-up, three patients (6.25%) suffered from continuous pain. Twelve cases (25.5%) showed radiological oversizing, though only five were symptomatic. Heterotopic ossification was detected in twenty-seven cases (57.4%). Eleven patients (23.4%) developed postoperative stiffness. Nineteen cases (40.42%) showed periprosthetic osteolysis, from which seven were symptomatic. Thirteen patients (27%) developed surgery-related complications: three cases of infection, four cases of symptomatic loosening, two neurapraxies, one instability and three cases of oversizing with associated stiffness. Nine patients (18.75%) required reintervention.

Our study obtains a 27% of overall complications, mostly related to oversizing and prosthetic loosening, and 19% of reinterventions. These results are similar to those presented in previous studies, with variations depending on the time of follow-up. Further research is also required to evaluate long-term results and the potential progression of the radiographic findings.

Taken together, these data stress the need for improvement in both the surgical technique and the design of the implants.