To determine the frequency and causes for limitations in the radiographic evaluation of surgically treated long bone fractures.

Six readers separately scored 140 sets of antero-posterior (AP) and lateral radiographs of surgically treated long bone fractures, using a radiographic union score (RUS). We determined the rate of assessability of the fracture edges at each of the four cortical segments (n=560) seen tangentially on the two radiographs and the causes for non-assessability. The rate of feasibility of the RUS (more than two fracture edges assessable per fracture) was determined and compared according to different parameters.

Fracture edges were visible in 71% to 81% of the 560 cortical segments. Metal hardware superimposition was the most frequent cause for non-assessability (79–95%). RUS values could be calculated in 58% to 75% of fractures. Scoring was statistically significantly less frequently calculable in plated (31–56%) than in nailed fractures (90–97%), in distal (47–61%) than in proximal (78–89%) bones and in upper (27–49%) than in lower (76–91%) limb bones (P≤0.01).

The type of stabilization hardware is the main limiting factor in the radiographic assessment of surgically treated long bone fractures. Scoring was feasible in only 31% to 56% of plated fractures.