Khushboo Pilania MD, Presenter: Nothing to Disclose

Bhavin Jankharia MD, Abstract Co-Author: Stockholder, Pfizer Inc Stockholder, Cipla Ltd Stockholder, Glenmark Pharmaceuticals Ltd

Rishab Bilala MBBS, Abstract Co-Author: Nothing to Disclose

The purpose of this study is to describe the significance and temporal evolution of incidentally detected, presumed, metal induced reactive periprosthetic masses in patients with metal on metal (MoM) hip arthroplasty and thus help decide the further plan of management.

Patients with MoM hip replacements fitted with a recalled implant (ASR, DuPuy) often undergo MRI with metal artifact reduction sequences (MARS) to look for complications. From a cohort of 136 asymptomatic patients, with 181 MoM hips, patients with a mention of periprosthetic soft tissue mass in their reports at first presentation were selected. Ethics committee approval is not required in our institution for retrospective studies. Eighty patients were selected. Those with complex masses and complications like loosening, osteomyelitis, focal particle disease, tendon tear were excluded. A search was then made amongst the rest for those who had a repeat scan within 6 months to 2 years. Twenty patients with 23 MoM hips fit these criteria. The two scans were then compared by two expert radiologists and all findings were arrived at by consensus. Progression was defined as increase in the size of collection or change in morphology i.e. increase in wall thickness, development of septae or altered signal intensity. Meticulous review for any new collection or complication in the interim was also made.  

Twenty asymptomatic patients with 23 MoM hips and 25 periprosthetic masses were evaluated. Comparison revealed that 13 of 25 reactive masses remained unchanged in shape, size and morphology over time. Eight of the 25 masses regressed, 2 of which completely resolved. Only 4 of the 25 lesions showed an increase in size. New periprosthetic mass was found in only 1 of the 23 hips. No significant new complication was noted in any of the patients. None of the patients turned symptomatic.

Periprosthetic soft tissue masses are not uncommon in patients with MoM hips. The majority of them in asymptomatic individuals remain stable or regress in the short to medium term and close follow-up or decisions on revision surgery may not be warranted in asymptomatic patients. 

Our study reveals that most of pseudotumors in patients with MoM hips, remain stable or regress, thereby stressing that decisions on revision may not be warranted in asymptomatic patients.

Pilania, K, Jankharia, B, Bilala, R, Longitudinal Follow-up of Incidentally Detected Pseudotumors in Patients with Metal on Metal Implants: A Prospective Study.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14017350.html