We assessed the short- to mid-term survival of metallic press-fit radial head prostheses in patients with radial head fractures and acute traumatic instability of the elbow.

The medical records of 42 patients (16 males, 26 females) with a mean age of 56 years (23 to 85) with acute unstable elbow injuries, including a fracture of the radial head requiring metallic replacement of the radial head, were reviewed retrospectively. Survival of the prosthesis was assessed from the radiographs of 37 patients after a mean follow-up of 50 months (12 to 107). The functional results of 31 patients were assessed using range-of-movement, Mayo elbow performance score (MEPS), Disabilities of the Arm, Shoulder and Hand (DASH) score and the RAND 36-item health survey.

At the most recent follow-up 25 prostheses were still well fixed, nine had been removed because of loosening, and three remained implanted but were loose. The mean time from implantation to loosening was 11 months (2 to 24). Radiolucent lines that developed around the prosthesis before removal were mild in three patients, moderate in one and severe in five. Range of movement parameters and mass grip strength were significantly lower in the affected elbow than in the unaffected side. The mean MEPS score was 86 (40 to 100) and the mean DASH score was 23 (0 to 81). According to RAND-36 scores, patients had more pain and lower physical function scores than normal population values.

Loosening of press-fit radial head prostheses is common, occurs early, often leads to severe osteolysis of the proximal radius, and commonly requires removal of the prosthesis.

There is little information available at present regarding the mechanisms of failure of modern metallic radial head implants. Between 1998 and 2008, 44 consecutive patients (47 elbows) underwent removal of a failed metallic radial head replacement. In 13 patients (13 elbows) the initial operation had been undertaken within one week of a fracture of the radial head, at one to six weeks in seven patients (seven elbows) and more than six weeks (mean of 2.5 years (2 to 65 months)) in 22 patients (25 elbows). In the remaining two elbows the replacement was inserted for non-traumatic reasons. The most common indication for further surgery was painful loosening (31 elbows). Revision was undertaken for stiffness in 18 elbows, instability in nine, and deep infection in two. There were signs of over-lengthening of the radius in 11 elbows. Degenerative changes were found in all but one. Only three loose implants had been fixed with cement. Instability was not identified in any of the bipolar implants.