Lumbar Spinal Fusion Increases Hip Dislocation Risk

Not so good news for patients who have a history of lumbar spinal fusion.

New research indicates that these folks are at a higher risk of experiencing a total hip arthroplasty (THA) dislocation than individuals who have not undergone lumbar spinal fusion.

The study, “Dislocation of a primary total hip arthroplasty is more common in patients with a lumbar spinal fusion,” was published April 28, 2017 in The Bone & Joint Journal.

Aaron J. Buckland, M.D. is a spinal and scoliosis surgeon and director of Spine Research at the New York University Hospital for Joint Diseases. He told OTW, “I had anecdotally noticed some late dislocations of total hip replacements in [a] patient that underwent lumbar fusion despite well positioned implants and a lack of wear. We then started looking at the effect of sitting and standing pelvic mechanics and noted that the pelvis does not retrovert to the same degree in sitting in those patients whom have had lumbar fusions. This theoretically would increase the risk of implant impingement and posterior dislocation. We therefore set out to investigate whether the presence of lumbar spinal fusion did in fact increase the risk of prosthetic dislocation in THA.”

“This paper utilized the United States Medicare and Medicaid services data over an eight-year period to look at the presence of dislocation at one year-post-total hip arthroplasty (THA). We stratified patients by the presence or absence of lumbar spinal fusion prior to THA, and for those patients who had a lumbar spinal fusion, we sub-stratified them by 1-2 level fusion versus 3-7 level fusion based on procedural billing codes.”

“Patients with a prior lumbar fusion had a higher dislocation rate after THA when compared to patients without a lumbar fusion. Patients with a 3-7 level spinal fusion had a higher rate of dislocation than those with 1-2 levels.”

“The results were as we expected. We are still unable to determine whether the sequence of lumbar spinal fusion versus THA affects the likelihood of dislocation.”

“Patients with lumbar spinal fusion pose a challenge when undergoing THA owing to their increased risk of dislocation. Further efforts should focus on patient-specific implant positioning in these patients.”