Total knee replacements can effectively treat degeneration caused by Blount disease, according to a study published online ahead of print July 11 in the Journal of Arthroplasty.
Middle-aged patients with Blount disease who underwent joint replacements on 1 or both knees were found to have stable knees, excellent range of motion, and no need for pain medications, according to the study conducted at Loyola University Medical Center in Illinois.
“With proper attention paid to technical details, patients with Blount or Blount-like deformity can undergo successful total knee arthroplasty,” said Harold Rees, MD, Assistant Professor of Reconstructive Surgery and Joint Replacement at Loyola University Chicago Stritch School of Medicine in Maywood, Illinois, and colleagues.
Harold Rees, MD
For the study, Dr. Rees and colleagues reviewed the records of 5 patients with Blount disease. Three patients had replacements on both knees and 2 patients had replacements on 1 knee. Four patients were African American and 4 were male. All were obese. The average age at the time of the knee replacements was 49.9. Patients were followed-up an average of 75.2 months after their knee replacements.
Mean proximal tibial metaphyseal-diaphyseal angle was 20.75 degrees. Each patient had substantial posteromedial tibial bony defects and 6 knees required extensive medial releases. Two knees required increased constraint at index procedure. One patient underwent bilateral revision surgery with rotating hinge prostheses.
The researchers used a scoring system, devised by the Knee Society, that combines clinical, functional, and satisfaction scores. The mean Knee Society score was 212.5, out of a maximum possible score of 255. Patients also were rated on the Western Ontario and McMaster Universities Osteoarthritis Index.
“The main purpose was to highlight surgical considerations in performing total knee arthroplasty in patients with Blount disease or Blount-like deformity. Despite a challenging patient population in which to perform total knee arthroplasty, we show that it can be done with a low risk of complication and reasonable medium-term results,” said the study authors. “Surgeons should be prepared to address posteromedial tibial bony defects and consider constrained arthroplasty at the index procedure,” they said.