Joint Arthroplasty, Osteopetrosis and Fracture Risk Study

Inspired by a patient, James Browne, M.D., an orthopedic surgeon at the University of Virginia, searched the literature to gather data on performing total knee arthroplasty (TKA) in patients with osteopetrosis.

Osteopetrosis is a rare disorder that causes bones to grow abnormally and become overly dense. When bones become overly dense, they are brittle and can fracture easily. In addition, bones may be misshapen and large, causing other problems in the body.

Finding scant information regarding patients with osteopetrosis, Dr. Browne enlisted colleagues to design and conduct a new study, “Osteopetrosis is Associated With an Increased Risk for Intraoperative Periprosthetic Fracture in Total Hip Arthroplasty but not in Total Knee Arthroplasty,” which appears in the August 13, 2022, edition of The Journal of Arthroplasty.

According to Dr. Browne and the other authors, “Osteopetrosis is a rare, inherited disorder in which abnormal bone remodeling causes bone to become pathologically dense due to a defect in bone resorption by osteoclasts.”

“Many of our research ideas are generated by patients we see in our clinical practice,” explained Dr. Browne to OTW. “A patient of mine had osteopetrosis and wanted to pursue total knee arthroplasty (TKA). When reviewing the literature, it became clear that there was very little in the literature on this condition and the risks associated with total joint arthroplasty. Given that osteopetrosis is a rare condition, the use of an administrative database with a large number of patients seemed like an appropriate way to try to study this question.”

Using the PearlDiver Patient Records Mariner Database (91 million patients from 2010 to 2020), the researchers searched for all TKA or total hip arthroplasty (THA) patients who had a history of osteopetrosis diagnosed prior to or at the time of their initial TJA. The team found 972 patients with a history of osteopetrosis who had undergone TKA; these patients were matched with 4,860 TKA patients with no history of osteopetrosis.

The researchers found that those in the osteopetrosis group who underwent THA had a substantially higher incidence of intraoperative periprosthetic fracture compared to the matched cohort (1.12 vs 0.19%). Interestingly, individuals with a history of osteopetrosis were not at significantly increased risk for other medical or surgical complications compared to matched controls following THA or TKA.

Dr. Browne commented to OTW, “We found that patients with a history of osteopetrosis undergoing elective primary total hip arthroplasty are associated with a significantly increased risk for intraoperative periprosthetic fracture. Interestingly, patients with a history of osteopetrosis undergoing elective primary total knee arthroplasty were not found to be at increased risk for any of the investigated complications.”

“Previous smaller studies have suggested that periprosthetic fractures occur more frequently during total hip arthroplasty in patients with osteopetrosis. This study confirmed that association using much larger numbers of patients. To our knowledge, the lack of association with complications in total knee arthroplasty has not been previously reported. This information can be helpful for the surgeon who is counseling a patient with osteopetrosis preoperatively regarding their risks of complications and poor outcome with total joint arthroplasty.”