Radiolucencies surrounding a smooth-stemmed radial head component may not correlate with forearm pain or poor elbow function

Hypothesis: Radiolucencies surrounding the stems of smooth-stemmed metal radial head prostheses placed for comminuted radial head fractures are associated with proximal radial forearm pain. Materials and methods: Patients in whom 18 consecutive elbows that underwent metal radial head replacement with smooth stems for comminuted radial head fractures were assessed at least two years after surgery. Proximal radial forearm pain was assessed with a visual analog score (0-10) and elbow function with a Mayo index. "Mean stem radiolucency" was determined by two musculoskeletal radiologists based upon three radiographs of each elbow: a lateral in maximum extension, a lateral in maximum flexion, and an antero-posterior. Results: All elbows were stable and stem radiolucencies were present in 16 of the 17 available for study. "Mean stem radiolucency" did not correlate with proximal radial forearm pain (p = 0.63) or Mayo scores (p = 0.37) using Spearman's correlation coefficients. 6/17 prostheses were in patients that rated their pain level as 0; 11/17 were in patients that rated their pain as at least 1 with 5 being the highest. Using the Signed Rank test, operative elbows had less motion for both flexion/extension (p = 0.0001) and pronation/supination (p = 0.01) compared to non-operative elbows from the same patient. Discussion: "Mean stem radiolucency" did not correlate with proximal radial forearm pain. However, proximal radial forearm pain was present in 11/17 elbows based upon visual analog scores. Proximal radial forearm pain in this population may have several etiologies. Conclusion: "Mean stem radiolucencies" surrounding smooth-stemmed metal radial head prostheses for fractures did not correlate with proximal radial forearm pain scores. Level of evidence: Level 4; Retrospective case series, no control group.