Spinal Imaging Pays Off – for Total Hip Replacement!

Is Preop spine imaging for total hip arthroplasty, cost justified?  We know that patients with abnormal spinopelvic mobility who undergo total hip arthroplasty (THA) are at increased risk of complications, but is the additional cost of spine imaging worth it?

A team of researchers from Penn State and Denver University decided to check that out and their work, “Cost-Effectiveness of Preoperative Spinal Imaging Before Total Hip Arthroplasty,” appears in the September 27, 2021 edition of The Journal of Arthroplasty.

Noting that acetabular component orientation is not a static parameter, the research team used seated and standing lateral lumbar spine radiographs to identify patients with a stiff/hypermobile spine (SHS), in order to, they hoped, inform any necessary alterations in acetabular cup placement or use of a dual-mobility hip construct.

Penn State’s Lucas Nikkel, M.D. explained to OTW, “Over the past several years more attention has been paid to the relationship between the hip and the spine as an under-recognized cause of instability after hip replacement. However, assessment of the spinopelvic relationship cannot be determined using traditional radiographs obtained prior to hip replacement.”

“As we learn more about how spinopelvic kinematics influence dislocation risk, we thought it appropriate to determine whether it was financially prudent to obtain additional radiographs on patients to determine those at risk.”

The team developed a decision model to compare the use of preoperative spinal imaging for pre-screening of stiff/hypermobile spine with the current standard of care (no such imaging accompanied by conventional hardware).

The four versions of the model were:

• a normal spine (conventional hardware),
• a normal spine (dual-mobility hardware),
• a patient with stiff/hypermobile spine (conventional hardware), and
• a patient with stiff/hypermobile spine (dual-mobility hardware).

The researchers found that “preoperative spinal imaging had a lifetime cost of $12,515 and quality-adjusted life years gains of 16.91 compared with no-screening ($13,331 and 16.77).

The preoperative spinal imaging strategy reached cost-effectiveness at 5 years and was dominant (i.e., less costly and more effective) at 11 years following THA.

In sensitivity analyses, preoperative spinal imaging remained the dominant strategy if prevalence of stiff/hypermobile spine was >1.9%, the cost of preoperative spinal imaging was <$925, and the cost of dual-mobility hardware exceeded the cost of conventional hardware by <$2,850.”

Co-author Jason Jennnings, M.D., DPT of Denver University told OTW, “Spine x-rays are cost effective prior to hip replacement surgery in an attempt to identify patients who may be at increased risk of dislocation. Identifying patients with spinal abnormalities in the setting of hip replacement surgery may help change planning of the orientation of the hip replacement or the type of implants selected by the surgeon.”