Open Access Research article

Histological, histomorphometric and microtomographic analyses of retrieval hip resurfacing arthroplasty failed at different times

Francesca Salamanna1*, Milena Fini12, Annapaola Parrilli1, Matteo Cadossi3, Nicolò Nicoli Aldini12, Gianluca Giavaresi12, Deianira Luciani3 and Sandro Giannini3

Author Affiliations

1 Laboratory of Biocompatibility, Innovative Technologies and Advanced Therapies, Rizzoli Research Innovation Technology, Rizzoli Orthopaedic Institute, Via di Barbiano 1/10, 40136, Bologna, Italy

2 Laboratory of Preclinical and Surgical Studies, Rizzoli Orthopaedic Institute, Bologna, Italy

3 II Orthopaedic and Traumatology Clinic, Rizzoli Orthopaedic Institute, Bologna, Italy

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BMC Musculoskeletal Disorders 2013, 14:47  doi:10.1186/1471-2474-14-47

Published: 30 January 2013

Abstract

Background

Metal-on-metal hip resurfacing arthroplasty (HR) has been gaining popularity especially for young and active patients. Although different series report good mid-term results, the long-term outcome and failure mechanisms are still concerning. In this consecutive revision case series, 9 retrieved specimens of a failed Birmingham Hip Resurfacing (BHR) were divided according to the time to fracture: 3 specimens failed at less than 6 months (Group 1), 3 failed between 6 months and 3 years (Group 2) and 3 failed later than 3 years (Group 3). The objective of the study was to examine by a specific quantitative histomorphometry and microtomography (micro-CT) method the characteristics of bone quality and its microarchitecture in retrieved metal-on-metal HR.

Methods

A series of 948 BHR were performed between 2001 and 2009. Among these implants 10 failures occurred and nine of these underwent revision surgery and were examined by histomorphometry and micro-CT.

Results

Histomorphometry showed a significant increase in trabecular separation (Tb.Sp) in Group 3 in comparison with Group 1 (113%, p < 0.05). In the top region, micro-CT showed that Groups 2 and 3 presented significant lower bone volume (Group 2: 61%, p < 0.005; Group 3: 1%, p < 0.05), trabecular number (Group 2: 53%, p < 0.005; Group 3: 40%, p < 0.05), and higher Tb.Sp (Group: 71%,p < 0.05) when compared to Group 1. Additionally, histomorphometry showed that the top regions in Group 1 had a significantly lower mean percentage of empty osteocyte lacunae than the top regions in both Group 2 and 3 (p < 0.05).

Conclusions

This study showed that the morphometric parameters considered are crucial for a good understanding of mechanical properties of HR and may be of significant importance in the pathogenesis of HR failure particularly in the development of late fractures.

Keywords:
Hip resurfacing arthroplasty; Failure; Histomorphometry; Microtomography