Corrosion of the Head-Stem Taper Junction—Are We on the Verge of an Epidemic?

Abstract

Background: The modular head taper junction has contributed to the success of total hip arthroplasty (THA) greatly. Taper corrosion and wear problems reported for large and extralarge metal-on-metal bearings as well as for bi-modular THA stems have cast doubt on the benefit of the taper interface. Presently, corrosion problems are being reported for nearly all kinds of artificial hip joints incorporating metal heads, questioning taper connections in general. Questions/purposes: This study aimed to review the mechanical and electrochemical relationships that may lead to taper corrosion, which have been reported more commonly in recent literature, and to also review the contribution of patient characteristics and surgical techniques involved in taper assembly that may contribute to the problem. Methods: The search criteria B(corrosion) AND (hip arthroplasty) AND (taper OR trunnion)^and B(hip arthroplasty) AND ((pseudotumor) OR (pseudo-tumor))^in PubMed and the JAAOS were used for the literature search. In addition, the arthroplasty registers were considered. Results: Most studies acknowledge the multifactorial nature of the problem but concentrate their analysis on taper and implant design aspects, since this is the only factor that can be easily quantified. The sometimes conflicting results in the literature could be due to the fact that the other two decisive factors are not sufficiently considered: the loading situation in the patient and the assembly situation by the surgeon. All three factors together determine the fate of a taper junction in THA. There is no single reason as a main cause for taper corrosion. The combined Boutcome^of these three factors has to be in a Bsafe range^to achieve a successful longterm taper fixation. Conclusion: No, this is not the beginning of an epidemic. It is rather the consequence of disregarding known mechanical and electrochemical relationships, which in combination have recently caused a more frequent occurrence-and mainly reporting-of corrosion issues.

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

“…The head size is not considered in Fessler's analytical model of fixation force (Figure 1). Since trunnionosis came into focus as clinically relevant, around ten years ago, multiple factors with a possible impact on the lever arm to the centre of rotation (e.g., large-diameter heads, high mediolateral offset, large neck length, and bearing type) have been discussed as factors that may exacerbate the fretting corrosion process [23,29,58,70]. However, the available data remain inconclusive as to their relevance, and their actual impact remains unclear even to date.…”

“…The aetiology of trunnionosis is believed to be a synergistic combination of factors related to the prosthesis, the patient, and the surgeon [19][20][21][22][23][24][25]. Trunnionosis involves both fretting corrosion as well as crevice corrosion [26,27].…”

Model-Based Roentgen Stereophotogrammetric Analysis to Monitor the Head–Taper Junction in Total Hip Arthroplasty in Vivo—And They Do Move

“…In addition to articular wear, many clinical studies have indicated corrosion between the femoral ball head component and the stem-taper as one of the sources of THA failure [9][10][11][12]. This phenomenon Materials 2020, 13,1543 3 of 21 is also called trunnionosis, which is defined as the wear and corrosion that occurs at the junction of the modular head-taper or neck-stem initialized by micromotion [13].…”

Investigation of Assembly Forces During Creation of Head-Neck Taper Junction Following Total Hip Arthroplasty: A Biomechanical Study

“…However, in the recent past there have been increasing reports of problems with taper junctions, which are usually accompanied by corrosion and abrasion. Especially metal-on-metal bearings are affected [7][8][9] but also ceramic bearings [10]. Such problems occur in primary [11] but also in revision THA [12].…”