Outcomes of Press-Fit Use of a Cementable Monoblock Radial Head Prosthesis in Complex Elbow Trauma: A Retrospective Observational Study.

backgroundRadial head arthroplasty is the preferred surgical strategy for unreconstructable radial head fractures associated with complex elbow injuries. Single-diameter monoblock prostheses remain widely used and are sometimes implanted off-label as press-fit, even when the manufacturer's instructions specify cementation. Outcome data on this practice are scarce. We aimed to describe the clinical, functional, and radiographic outcomes of a single-diameter monoblock partial radial head prosthesis implanted off-label as a press-fit for complex elbow trauma.

methodsWe retrospectively reviewed 35 consecutive adult patients treated with the same single-diameter monoblock partial radial head prosthesis for complex elbow trauma between January 2021 and January 2024 at a tertiary referral center. The implant was used off-label, as the manufacturer's instructions specify bone-cement fixation. Injury patterns included terrible triad, Monteggia variants, transulnar fractures involving the coronoid base, and isolated irreparable radial head fractures. The primary outcomes were periprosthetic radiolucency and implant loosening at the 24-month radiograph and the association between them; secondary outcomes were the Mayo Elbow Performance Score (MEPS), range of motion, visual analog scale (VAS) for pain, return to work, and postoperative complications. The association between radiolucency and loosening was tested with Fisher's exact test (two-tailed).

resultsThe mean age was 48.5 ± 13.6 years (range, 27-75); 20 (57.1%) were male patients, and the dominant limb was injured in 13 patients (37.1%). The most frequent injury pattern was the terrible triad (60.0%). With a minimum follow-up of two years and a mean follow-up of 30 months (range, 24-36 months), mean elbow flexion was 117.7°± 13.9°, mean extension deficit was 20.3°± 17.0°, and mean combined forearm rotation was 138.9°. A functional arc of motion was achieved in 57.1%. MEPS was good or excellent in 22 patients (62.9%; 95% CI, 46.3-76.8); mean VAS pain at last follow-up was 2.0 ± 1.7 (range, 0-6); 25 (71.4%) returned to their previous occupation. Periprosthetic radiolucency was identified in 30 (85.7%) and implant loosening in 15 (42.9%; 95% CI, 27.7-59.4%); interrater agreement between two blinded elbow specialists who did not perform any of the surgeries was almost perfect (Cohen's κ = 0.91 (95% CI, 0.81-1.00) for radiolucency and κ = 0.93 (95% CI, 0.85-1.00) for loosening). All patients with loosening exhibited radiolucency; however, this association did not reach statistical significance on a two-tailed Fisher's exact test (p = 0.057). Postoperative deep infection occurred in one patient (2.9%); no permanent neurological injury was recorded; four patients (11.4%) underwent reoperation (one infection, one stiffness, one instability, one symptomatic complication managed with hardware removal).

conclusionOff-label press-fit use of a cementable monoblock radial head prosthesis produced satisfactory short- to mid-term functional outcomes with an acceptable complication profile. Although periprosthetic radiolucency was highly prevalent and implant loosening occurred in nearly half the cohort, most radiographic findings remained clinically silent, and reoperation was infrequent. These data support the press-fit use of this implant as a viable option in resource-limited settings, while highlighting the importance of systematic radiographic surveillance and longer-term follow-up.