Variability in stem taper surface topography affects the degree of corrosion and fretting in total hip arthroplasty

AbstractDegradation at the modular head-neck interface in total hip arthroplasty (THA) is predominately expressed in the form of corrosion and fretting, potentially causing peri-prosthetic failure by adverse reactions to metal debris. This retrieval study aimed to quantify variations in stem taper surface topographies and to assess the influence on the formation of corrosion and/or fretting in titanium alloy stem tapers combined with metal and ceramic heads. Four hip stem designs (Alloclassic, CLS, Bicontact and SL-Plus) were characterized using high-resolution 3D microscopy, and corrosion and fretting were rated using the Goldberg scoring scheme. Quantification of the taper surface topographies revealed a high variability in surface characteristics between threaded stem tapers: Alloclassic and CLS tapers feature deeply threaded trapezoid-shaped profiles with thread heights over 65 µm. The sawtooth-shaped Bicontact and triangular SL-Plus taper are characterized by low thread heights below 14 µm. Significantly lower corrosion and fretting scores were observed in lightly threaded compared to deeply threaded tapers in ceramic head combinations. No significant differences in corrosion or fretting scores with thread height were found in pairings with metal heads. Understanding the relationship between stem taper surface topography and the formation of corrosion and fretting could help to improve the performance of modern THAs and lead to longer-lasting clinical results.

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Small-head metal on metal total hip arthroplasty is associated with a high rate of complication and reoperation at mid-term follow-up

SAGE Open Medicine ◽

10.1177/20503121211014707 ◽

2021 ◽

Vol 9 ◽

pp. 205031212110147

Author(s):

Nobuhiko Sumiyoshi ◽

Kazuhiro Oinuma ◽

Yoko Miura

Keyword(s):

Total Hip Arthroplasty ◽

Hip Arthroplasty ◽

Adverse Reactions ◽

Small Diameter ◽

High Rate ◽

Metal Debris ◽

Total Hip ◽

Metal On Metal ◽

Small Head

Background: Adverse reactions to metal debris are significant complications after metal-on-metal total hip arthroplasty. Recently, late appearances of adverse reactions to metal debris and subsequent need for reoperations have been reported with small-diameter head metal-on-metal devices. We retrospectively investigated mid-term clinical outcomes of small-head metal-on-metal total hip arthroplasty. Methods: We reviewed 159 hips in 139 patients who had a small-head metal-on-metal total hip arthroplasty (M2a Taper; Biomet, Warsaw, IN) with a minimum 5-year follow-up and documented postoperative complications. Results: Focal osteolysis in either the femur or acetabulum was observed in 12 hips (7.5%, 44 months after surgery on average), with pseudotumor observed in 8 hips (5%, 120 months after surgery on average). Four hips (2.5%) had dislocations (84 months after surgery on average) and six hips (3.8%, 122 months after surgery on average) underwent reoperation. Conclusion: Small-head metal-on-metal total hip arthroplasty is associated with a high degree of complications at mid-term follow-up period. Considering this, we discourage the use of metal-on-metal total hip arthroplasty regardless of head size.

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Clinical, functional and radiographic outcomes after revision total hip arthroplasty with tapered fluted modular or non-modular stems: a systematic review

Hip International ◽

10.1177/11207000211004383 ◽

2021 ◽

pp. 112070002110043

Author(s):

Antonios A Koutalos ◽

Sokratis Varitimidis ◽

Konstantinos N Malizos ◽

Theofilos Karachalios

Keyword(s):

Total Hip Arthroplasty ◽

Hip Arthroplasty ◽

Revision Rate ◽

Clinical Results ◽

Fracture Rate ◽

Revision Total Hip Arthroplasty ◽

Term Survival ◽

Total Hip ◽

Radiographic Outcomes

Purpose: The aim of the study was to systematically evaluate clinical outcomes of tapered fluted stems, either monoblock or modular, in revision total hip arthroplasty. Methods: PubMed, EMBASE and Web of Science and Cochrane databases were systematically searched by 2 researchers. Clinical studies reporting primarily on survival and re-revision rates, and secondarily on subsidence, dislocation, intraoperative fractures, periprosthetic fractures and infection were included. 2 investigators assessed the quality of the studies. Results: 46 studies were included in this review, reporting on 4601 stem revisions. The pooled re-revision rate was 5.1% and long-term survival ranged from 75% to 98.5%. No differences were observed between monoblock and modular stems regarding re-revision rate, dislocation rate, periprosthetic fracture rate or infection rates. Monoblock stems exhibited more subsidence and modular stems displayed more intraoperative fractures. Conclusions: Satisfactory results can be obtained with the use of tapered fluted end-bearing stems. Monoblock stems offer the same clinical results as modular stems.

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Reliability of Total Nucleated Cell Counts in the Setting of Hip Arthroplasty

The Journal of Applied Laboratory Medicine ◽

10.1093/jalm/jfaa183 ◽

2020 ◽

Author(s):

Lauren N Pearson ◽

Robert L Schmidt ◽

Kenneth Cahoon ◽

Christopher E Pelt

Keyword(s):

Synovial Fluid ◽

Total Hip Arthroplasty ◽

Hip Arthroplasty ◽

Metal Debris ◽

Total Hip ◽

Cell Counts ◽

History Of ◽

Joint Effusions ◽

Automated Instruments ◽

Automated Methods

Abstract Background Total nucleated cell (TNC) count and differential are used to classify joint effusions as inflammatory or noninflammatory. Further diagnostic evaluation and management is contingent on this classification. TNC count can be measured by automated analyzers or by manual assessment using a hemocytometer. Studies have raised concerns regarding the accuracy of TNC counts measured by automated instruments, particularly in the setting of joint arthroplasty. The objective of this study was to determine whether metallosis, a complication of total hip arthroplasty in which metal debris accumulates in periprosthetic tissues and synovial fluid, is associated with inaccurate TNC counts in synovial fluid. Methods We compared the accuracy of cell counts measured by the Sysmex XN-1000 and Beckman Coulter Iris iQ200 with the gold standard of manual assessment using a hemocytometer in synovial fluid from patients with suspected metallosis and in fluid obtained from controls from patients with native joints and a history of arthroplasty for other indications. Results TNC counts produced by automated analyzers were associated with increased levels of discordance (relative to manual counts) in patients with metallosis. Metallosis was not associated with increased levels of discordance for RBC counts or WBC differentials. The Sysmex XN flagged all but 1 metallosis sample for manual verification of the results. Conclusions Automated methods are generally reliable for analysis of synovial fluid. TNC counts can be inaccurate in the context of metallosis following total hip arthroplasty. Laboratories should correlate automated cell counts with a microscopic assessment of the specimen, as recommended by instrument manufacturers.

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