A positive hip arthrogram may predict lower function in patients with primary hip arthroplasty.

Background: A local anesthetic hip arthrogram is a simple test mainly used as an adjunct to define the origin of hip pain. Temporary pain relief (a positive response) following an injection may lead to a surgeon recommending hip surgery. However, it is unclear whether relief of pain corresponds to better postoperative pain relief or function.

Questions/purposes: We therefore compared the function in patients with a positive response to a local anesthetic hip arthrogram who underwent primary THA and patients with typical osteoarthritis presentation who underwent primary THA without a preoperative arthrogram.

Methods: We retrospectively reviewed 22 patients who had a positive response to a local anesthetic hip arthrogram who subsequently underwent primary hip arthroplasty and a control group of 74 patients who had typical osteoarthritis hip pain and subsequent primary hip arthroplasty without having a previous arthrogram. All patients completed the Oxford Hip Score, WOMAC™ function short form, and the SF-12 preoperatively and at regular clinical followups. The minimum followups were 28 months (mean, 42 months; range, 28-72 months) for the study group and 33 months (mean, 52 months; range, 33-73 months) for the control group.

Results: Patients in the arthrogram group had lower mean functional scores: 30 versus 39 for the Oxford Hip Score, 39 versus 46 for the WOMAC™, and 36 versus 42 for the physical component of the SF-12.

Conclusions: Preoperative use of a local anesthetic hip arthrogram remains an important tool to differentiate spinal disorders or confirm the hip as the cause of pain. However, patients who have a preoperative hip arthrogram to clarify symptoms may report a lower function score and pain relief than patients who do not.