Objectives: To study the correlation between quantitative ultrasound (QUS) expressed as stiffness index (SI) and the risk of aseptic loosening of knee arthroplasty. Methods: An observational retrospective controlled study was performed on 85 female patients (mean age: 73.3 years) divided into 2 groups from January 2007 to March 2015 and carried out at the Orthopedic Rehabilitation Unit, Casa di Cura Eremo, Arco, Trento, Italy. Group A included 42 patients who had undergone a revision of knee prosthesis for aseptic-loosening, and group B included 43 age-matched patients who underwent primary replacement of the knee without following aseptic loosening. Patients in both groups were evaluated for SI with Achilles - QUS system at the same side of the surgery. Results: In group A, 20/42 patients (47.6%) had an SI T-score below -2.5. In group B, 14/43 (32.5%) patients had a SI T-score below -2.5. The difference between the 2 groups was statistically significant (p=0.015). Conclusion: Stiffness index appears to be an important predictor of aseptic loosening of the knee prosthesis. Therefore, densitometric evaluation, including SI, may be recommended before surgical knee replacement.
ASJC Scopus subject areas