Patellar component replacement in stage-one revision TKA for PJI may improve outcomes
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Key takeaways:
- Patellar replacement in stage-one revision total knee arthroplasty reduced lateral patellar displacement.
- Fracture rate was higher in patients who did not receive a patellar replacement at stage-one revision.
SAN FRANCISCO — Results presented here showed replacing the patellar component in stage-one revision total knee arthroplasty may improve outcomes in patients with a periprosthetic joint infection.
“We found replacing the patellar component at stage one for PJI was associated with a decreased lateral subluxation of the patella between stages, decreased patella fracture, a better observed patella bone stock at stage two and an increased ability to replace the patella component at stage two without differences in reinfection rates,” Joshua Rainey, MD, a fourth-year resident at the University of Utah, said in his presentation at the American Academy of Orthopaedic Surgeons Annual Meeting.
Rainey and colleagues retrospectively reviewed data for 139 patients who underwent stage-one revision TKA for periprosthetic joint infection from 2013 to 2022. Researchers compared patellar radiographic measurements, range of motion, extensor mechanism complications and infection recurrence between patients who underwent patellar component removal without replacement (n=91) with patients who had an all-polyethylene patellar component placed at stage-one revision (n=48).
Six weeks after stage-one revision, patients who received a patellar replacement had significantly less lateral patellar displacement at 1.7 mm compared with 16 mm in patients who did not receive a patellar replacement, Rainey said.
“It should be noted that, in the removal only cohort, they had significantly thinner patella after stage one, but this translated to only about a millimeter of difference, 14 mm vs. 15.1 [mm],” Rainey said. “Patients in the removal only group also had a larger loss of patellar bone stock between stages.”
He added that patients in the removal only group were significantly more likely to be unable to be resurfaced in stage two and patients in the patellar replacement group had an increase in knee range of motion after patellar component replacement in stage one. Patients in the removal only group had a 12% fracture rate vs. 2% in the replacement group, according to Rainey.
“There were no differences in extensor mechanism reconstruction at stage two, extensor lags, recurrence of infection or extensor mechanism of failures at any point,” he said.
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Rainey J, et al. Paper 470. Presented at: American Academy of Orthopaedic Surgeons Annual Meeting; Feb. 12-16, 2024; San Francisco.
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