Alexandre Di Iorio

Understanding wear in dual mobility total hip replacement: first generation explant wear patterns

PurposeDual mobility was introduced by Pr. G. Bousquet to improve the dislocation risk of total hip arthroplasty (THR). The wear mechanisms of this implant remain to be understood. Could enhanced explant wear analysis explain liner wear behaviour?MethodsSixty-six explanted liners were selected. Non-destructive 3D scanning and heat colour treatment allowed reporting wear patterns on both convex and concave sides of the liners.ResultsFor many liners, liner convexity wear was found to be homogeneous, and linked to a longer implantation time. A few liners had signs of blocking of the convexity, leading to excessive internal damage. Intra prosthetic dislocations were found to only have internal circular wear without liner penetration.ConclusionHeat colour treatment showed its effectiveness for highlighting wear patterns. Optimal convexity mobility seemed to be leading to a longer implantation time, with decreased contact stresses on concavity. The retentive rim should have a distinct wear analysis.

The linear penetration rate is not relevant for evaluating wear of dual mobility cups: an explant study

PurposeThe linear penetration rate (LPR) has been used to estimate volumetric wear ever since metal-on-polyethylene bearings were first introduced. Annual volumetric wear and osteolysis are interrelated. The use of dual mobility cups has increased; however, the presence of two bearings needs paraclinical monitoring of wear to anticipate potential wear-related complications. Is LPR correlated to volumetric wear?MethodsNinety-eight dual mobility liner retrievals were mapped in three-dimensions (3D) with a fully automatic stripe light scanner. Martell’s method was applied to 3D maps of the explants to determine how much the centres of the inner and outer bearings had shifted in the three planes, and in particular, penetration of the femoral head in the “z” axis. The total, inner and outer wear volumes were then compared to the shift in the centres of rotation (COR) and the pre-operative X-rays.ResultsThere was no relationship between wear and head penetration into the liner. There was a statistically significant relationship between the 3D centre of rotation shift and inner wear or total wear. Wear was multidirectional.ConclusionsLPR is ineffective for estimating wear of dual mobility inserts, since its wear not two-dimensional. In the future, a 3D imaging method with very thin slices could be used to monitor the wear of dual mobility inserts by measuring the shift in the centres of rotation, once artifacts are overcome.

Management of Periprosthetic Cystic Changes After Total Ankle Replacement

Total ankle replacement (TAR) was developed in the 1970s as an alternative to arthrodesis in selected patients. It is a challenging procedure in the treatment of osteoarthritis. However, some previous studies have shown a high percentage of rapidly progressing osteolysis associated with TAR. The cause of these cysts remains unclear. Diagnosis requires rigorous assessment and regular follow-up. Depending on the cystic changes, different therapeutic options are available including cyst curettage–bone grafting, revision arthroplasty, or arthrodesis.

Correction to: Intraprosthetic dislocation of dual mobility total hip arthroplasty: still occurring?

The published online version contains mistake in the author list for the author name “Di Iorio Alexandre” was incorrectly presented.