Prevalence and Clinical Impact of Incidental Findings on Preoperative Computed Tomography for Hip Arthroscopy

Patients routinely undergo computed tomography (CT) before arthroscopy for femoroacetabular impingement as part of preoperative planning. These scans include the lower lumbar spine, entire pelvis, proximal femur, knees, and ankles, raising questions about the prevalence and clinical impact of incidental findings (IFs) from these images.

To evaluate factors associated with IFs, as well as their prevalence, management, and impact on patient outcomes.

Cohort study; Level of evidence, 3.

This was a retrospective review of preoperative pelvic CT scans from a single surgeon's hip outcomes registry. Additional details regarding specific participants were obtained through electronic medical records. Logistic regression analysis was used to compare the effects of predictors of interest on the likelihood of having an IF on CT imaging. Repeated-measures mixed modeling was utilized to examine the effect of IFs on patient-reported outcomes obtained at 6 weeks, 3 months, 6 months, 1 year, and 2 years postoperatively.

A total of 714 preoperative CT reports in 596 patients were reviewed; IFs were present in 306 of the scans (42.9%). Most IFs were of skeletal pathology (78.1%), followed by soft tissue (7.8%), reproductive (6.9%), abdominal (4.2%), and urologic (2.9%). Of the 306 IFs, 10 (3.3%) required further medical workup. Multivariate analysis indicated that patient factors associated with an IF included age (P < .0001). Presence of an IF on preoperative imaging was associated with lower values both pre- and postoperatively on the Hip Outcome Score activities of daily living (P = .04) and sports-specific subscale (P = .03), the 12-item International Hip Outcome Tool (P = .02), and the Patient-Reported Outcomes Measurement Information System-Mobility measure (P = .03). Although statistically significant, these findings did not exceed the minimal clinical important difference (MCID) for these scores.

The presence of IFs on CT imaging was associated with significant decreases across multiple outcome scores; however, the differences in scores did not exceed the MCID for any outcome. The high prevalence of IFs necessitates implementation of a reliable standardized follow-up protocol. This could improve overall patient care by reassuring patients of benign findings or providing treatment for potentially harmful ones.