Lumbar Fusion Before THA=Higher Dislocation?

Citing a 239% increase in patients undergoing both lumbar spine fusion and total hip arthroplasty (THA) over the past 10 years, researchers from the Bioengineering Laboratory in the Department of Orthopaedic Surgery at Massachusetts General Hospital, Harvard Medical School, dove in to determine how dislocation and revision rates are impacted by the timing of a lumbar spine fusion before THA.

Their work, “Lumbar Spine Fusion Before Revision Total Hip Arthroplasty is Associated with Increased Dislocation Rates,” appears in the September 1, 2021 edition of The Journal of the American Academy of Orthopaedic Surgeons.

An Associate Professor of Orthopaedic Surgery at Harvard Medical School, co-author Young-Min Kwon, M.D., Ph.D., who also specializes in minimally invasive total hip and knee replacements and complex revision surgeries, explained the genesis of this study to OTW, “The number of lumbar spinal fusions and THA procedures performed every year in the United States continues to rise due to an ageing population, with literature data report a 239% increase in the prevalence of patients undergoing both lumbar spinal fusion and THA over the past 10 years.”

“There is increasing evidence that patients with spinal and lumbar pathology necessitating both lumbar spinal fusions and primary THA have increased rates of post-operative complications.”

“Revision surgery represents a complex surgical procedure that remains an overwhelming burden for patient outcomes and healthcare costs, with revision surgery, when compared to primary THA, being associated with an increased median length of stay, higher post-operative complication rates and an increased annual economic burden.”

“As there is a paucity of data investigating the effect of the timing of lumbar spinal fusion following revision THA on complication rates, we aimed to determine if timing of lumbar spinal fusion following revision THA would have an effect on dislocation and re-revision rates.”

The researchers looked at 505 patients who’d been treated with revision THA and were diagnosed with degenerative lumbar spinal stenosis with spondylolisthesis. The first group of 328 patients received revision THA with previous lumbar spinal fusion; the second group of 177 patients received revision THA, followed by lumbar spinal fusion.

Of the 328 patient group, 192 (58.5%) received revision THA with previous lumbar spinal fusion within one year and 136 patients (41.5%) were treated with revision THA and had had lumbar spinal fusion within six months. The group with 177 patients included 71 (40.1%) who’d been treated with revision THA, followed by lumbar spinal fusion within one year and 106 patients (59.9%) who underwent revision THA, followed by lumbar spinal fusion within 1 to 2 years. The researchers had a control cohort of 305 patients who’d had revision THA without any spinal fusion before or after surgery.

Timing IS Everything

Dr. Kwon summarized the outcome of the study to OTW, “Our study demonstrates increased cumulative dislocation and re-revision rates for patients that underwent revision THA with prior lumbar spinal fusion, when compared to patients that underwent revision THA followed by lumbar spinal fusion. Furthermore, we have found that the timing of lumbar spinal fusion following revision THA influences post-operative complication rates, with the greater the interval between revision THA and lumbar spinal fusion, the lower the risk for post-operative complications including dislocations and re-revisions.”

“Our study findings suggest that patients with concomitant elective non-urgent revision THA as well as lumbar spinal fusion surgery may benefit from undergoing revision THA prior to lumbar spinal fusion surgery in order to minimize dislocation rates.”