Clinical efficacy and cost-effectiveness of postoperative radiographs after total knee arthroplasty.

Background: Postoperative radiographs are commonly ordered after primary total knee arthroplasty (TKA), however, there is limited data on how often these films change management over the entire postoperative time course, and what should prompt imaging to maximize clinical utility.

Methods: A retrospective cohort study was conducted of patients ≥ 18 years old who underwent a primary TKA at two level one trauma centers. Postoperative data were collected to determine the frequency of postoperative radiograph series, radiograph findings that did not suggest normal healing or alignment to radiologist and orthopedists, and changes in postoperative management. The total cost and radiation exposure values were calculated for all patient radiographs using estimates from previous literature.

Results: From the 1258 patients included, 3831 postoperative radiographs were taken (mean ± 95% confidence interval [CI]: 3.05 ± 0.11 radiographs per patient). Of these 3831 radiographs, 44 (1.1%) contained a positive radiographic finding. Only 13 (0.3% of radiographs) of these positive radiographic findings were positive orthopaedic findings, 11 of which led to changes in management. For all but 1 of these patients (10/11, 91%), these radiographs were taken during a non-routine postoperative visit. Routine postoperative radiographs that did not change management cost $1,008,480 and administered 22.92 mSV of radiation to patients within this study.

Conclusion: Postoperative radiography obtained after primary TKA were of low clinical utility yet resulted in considerable healthcare costs and unnecessary radiation burden. Radiographs ordered during a non-routine visit, however, were a reliable indicator of when this imaging provided clinical utility.