Abstract 18

Relationship between progression of osteolysis adjacent to hip prostheses and POLYETHYLENE wear

Roumen Stamenkov, Susan Neale, Margaret McGee, David Findlay¹, James Taylor², George Kourlis², Susan Pannach, Donald Howie¹

Department of Orthopaedics and Trauma, Royal Adelaide Hospital and University of Adelaide, ¹Hanson Institute, and ²Department of Radiology, Royal Adelaide Hospital

Purpose: Knowledge of the extent and progression of peri-prosthetic osteolysis (PPO) is important in monitoring and surgical management of total joint replacement patients, and to determine effects of medical treatments. The aim of this study was to use quantitative computed tomography (CT), with wear and migration analyses, to determine the rate of progression of PPO and its relationship to wear of the polyethylene (PE) cup.

Methods: PPO adjacent to 19 well-fixed Harris-Galante acetabular components was measured at 12-month intervals. Migration analyses were used to exclude cases with migrated components. Volumetric PE wear was determined from digitised X-rays using the Polyware software program. Patient-related factors including age, gender, BMI, activity levels, comorbidities, and joint pain and function were recorded from our Joint Replacement Database.

Results: Lesions in many of these patients were relatively quiescent, while others progressed markedly over a one year period. There was a significant association between progression of osteolysis and total PE wear, PE wear rate and volumetric PE wear in the 12 month period between CT scans (p=0.026, p=0.025 and p=0.035, respectively). None of the other covariates examined was significantly associated with the progression of osteolysis.

Conclusions: CT measurement of PPO progression and accurate estimates of cup wear and stability provide important information to guide clinical management of total hip replacement patients. The data support the involvement of PE particles in bone destruction in these individuals.

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