Could Novel Radiographic Findings Help Identify Aseptic Tibial Loosening?

BACKGROUND: Aseptic loosening following total knee arthroplasty remains one of the leading causes of long-term failure. Radiographic identification of loose implants can be challenging with standard views. The purpose of this study was to compare the incidence of novel radiographic findings of anterior heterotopic bone formation and medial or lateral cyst formation in patients who have aseptic loosening to patients who have well-fixed implants. METHODS: A retrospective radiographic review was performed on 48 patients' revised secondary to aseptic tibial loosening. This cohort was compared to two additional cohorts; 48 patients returning for routine postoperative follow-up (control 1), and 48 patients revised secondary to infection or instability who had well-fixed implants (control 2). RESULTS: There were 41 of 48 (85%) patients who had implant loosening and were noted to have anterior heterotopic bone formation compared to 1 of 48 (2%) patients in control 1 and 3 of 48 (6%) patients in control 2 (P ≤ .0001). There were 43 of 48 (90%) patients who had implant loosening and had medial cyst formation compared to 3 of 48 (6%) patients in control 1 and 5 of 48 (10%) in control 2 (P ≤ .0001). There were 42 of 48 (88%) patients who had implant loosening and had lateral cyst formation compared to 2 of 48 (4%) patients in control 1 and 4 of 48 (8%) in control 2 (P ≤ .0001). CONCLUSION: In this study, we describe novel radiographic findings of anterior heterotopic bone formation and cysts that develop in patients who have aseptic loosening following primary total knee arthroplasty. We believe that these radiographic features may lead to easier identification of aseptic loosening.

Diagnosis and Prevention of Periprosthetic Joint Infections.

The Diagnosis and Prevention of Periprosthetic Joint Infections Clinical Practice Guideline is based on a systematic review of current scientific and clinical research. Through analysis of the current best evidence, this guideline seeks to evaluate strategies to mitigate the risk of periprosthetic joint infection (PJI) in hip and knee arthroplasty and identify best practices in the diagnostic evaluation for these infections. Twenty-five recommendations related to prevention and diagnosis of PJI are presented. In addition, the work group highlighted areas for needed additional research when evidence proved lacking on the topic and carefully reviewed the rationale behind the recommendations while also noting potential harms or risks associated with implementation.