What the Surgeon Can Do to Reduce the Risk of Trunnionosis in Hip Arthroplasty: Recommendations from the Literature.

Claude B. Rieker,Peter Wahl

doi:10.3390/ma13081950

Claude B. Rieker, Peter Wahl

Open Access

https://doi.org/10.3390/ma13081950

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Abstract

Trunnionosis, defined as wear and corrosion at the head–neck taper connection, is a cause of failure in hip arthroplasty. Trunnionosis is linked to a synergistic combination of factors related to the prosthesis, the patient, and the surgeon. This review presents analytical models that allow for the quantification of the impact of these factors, with the aim of providing practical recommendations to help surgeons minimize the occurrence of this failure mode. A tighter fit reduces micromotion and, consequently, fretting of the taper connection. The paramount parameters controlling the fixation force are the coefficient of friction and the impaction force. The influence of the head diameter, as well as of the diameter and angle of the taper, is comparatively small, but varus alignment of the taper and heads with longer necks are unfavourable under physiologic loads. The trunnion should be rinsed, cleaned, and dried carefully, while avoiding any contamination of the bore—the female counterpart within the head—prior to assembly. Biological debris, and even residual water, might critically reduce the fixation of the taper connection between the head and the neck. The impaction force applied to the components should correspond to at least two strong blows with a 500 g hammer, striking the head with an ad hoc impactor aligned with the axis of the taper. These strong blows should correspond to a minimum impaction force of 4000 N.

Highlights

Total hip arthroplasty (THA) is so successful in restoring mobility and relieving pain in patients with degenerated hip joints [1] that it has been nominated as the operation of the 20th century [2]
Contemporary hip arthroplasty includes modular heads with variable neck lengths, as this increases the surgical options to tailor the implant to the patient’s individual anatomy and allows for the use of heads made of materials that differ from that of the stem [7]
Since the first report of a pseudotumour related to taper corrosion was published as early as 1988 [82], corrosion and fretting at the taper junction have become increasingly linked to implant failure [11,12,13,20,22,83]

Summary

Introduction

Total hip arthroplasty (THA) is so successful in restoring mobility and relieving pain in patients with degenerated hip joints [1] that it has been nominated as the operation of the 20th century [2]. Modularity gives the surgeon the flexibility to choose femoral heads of varying materials and diameters, with variable neck lengths, so that the joint replacement can be adjusted according to the patient’s anatomy [7]. Long-term MACC leads to material loss at the taper junction, which can, in rare cases, lead to the frank dissociation of the connection, as well as marked taper deformity [13,20,32,33,34] This manuscript aims to quantify the impact of these factors according to published analytical models, as well as clinical and in vitro studies, and provide practical recommendations to help surgeons minimize the occurrence of trunnionosis. We conducted a thorough non-systematic review of the literature using two search engines (PubMed and Google Scholar, using the following keywords: trunnionosis, fretting corrosion, taper connection, taper corrosion, taper failure, MACC, modularity, assembly force, disassembly force, micromotion) and cross-referenced related studies to identify the relevant literature

Technical Aspects of Taper Connections in Hip Arthroplasty

Influence the diameter of theonhead on fixation as estimated

Patient-Related Factors for Trunnionosis

Surgeon-Related Factors Determining Taper Fixation

Findings

Discussion