Retrieval analysis in total knee arthroplasty

Abstract

Retrieval analysis in total knee arthroplasty (TKA) has been little studied in the literature. A narrative review of the literature to understand the current importance of retrieval analysis in TKA has been conducted. On August 27, 2024, a literature search was performed in PubMed using “TKA retrieval analysis” as keywords. A total of 160 articles were found, of which only 19 were analyzed because they were directly related to the subject of this article. Rotating-platform (mobile-bearing) TKA has no surface damage advantage over fixed-bearing TKA. TKAs with central locking mechanisms are more prone to debond from the cement mantle. No major wear of the polyethylene (PE) component in TKA using oxidized zirconium components occurs. Femoral components of cobalt-chromium roughen more than oxidized zirconium femoral components. The use of a polished tibial tray over an unpolished design is advised. At short-run assessment (15 months on average), antioxidant-stabilized highly crosslinked PE components are not clinically different in surface damage, density of crosslinking, or oxidation compared to standard remelted highly crosslinked PE components. A correlation between implant position and PE component surface damage has been reported. It shows the importance of optimizing component position to reduce PE component damage. Contemporary knee tumor megaendoprostheses show notable volumetric metal wear originated at the rotating hinge. Retrieval analysis in TKA renders relevant data on how different prosthetic designs described in the literature perform. Such information can help to improve future prosthetic designs to increase prosthetic survival.

Key Words: Total knee arthroplasty; Retrieval analysis; Results; Knee; Orthopedics

Core Tip: Rotating-platform (mobile-bearing) total knee arthroplasty (TKA) has no surface damage advantage over fixed-bearing TKA. TKAs with central locking mechanisms are more prone to debond from the cement mantle. No major wear of the polyethylene component in TKA using oxidized zirconium components occurs. Femoral components of cobalt-chromium roughen more than oxidized zirconium femoral components. The use of a polished tibial tray over an unpolished design is advised. Retrieval analysis in TKA renders relevant data on how different prosthetic designs utilized in the literature perform. Such information can help to improve future prosthetic designs in order to increase prosthetic survival.

INTRODUCTION

Retrieval analysis in total knee arthroplasty (TKA) has been little studied in the literature[1-17]. This article has conducted a narrative review of the literature to understand the current importance of retrieval analysis in TKA. Important aspects of retrieval analysis in TKA, such as implant longevity, wear patterns and clinical correlations, were specifically analyzed. Neither reviews nor meta-analyses on this subject were identified in a literature search. Nineteen articles selected from among the 160 publications examined in PubMed covering the period from the beginning of the search engine until August 27, 2024 were analyzed and an update on the subject of TKA retrieval analysis to be developed.

RETRIEVAL ANALYSIS METHODOLOGY

On August 27, 2024, a literature search was performed in PubMed using “TKA retrieval analysis” as keywords. A total of 160 articles were identified. However, subsequent review revealed 141 manuscripts were not directly related to the subject. Accordingly, only 19 publications were deemed suitable for further analysis. The main methods of study on TKA retrieval analysis have been summarized in Tables 1 and 2[18,19].

Table 1 Metrology tools to investigate the root cause of implant failure.

Qualitative methods	Quantitative methods
Visual investigation	Semi-quantitative methods, such as Hood, Goldberg and other visual scoring systems
Microscopic investigation	Gravimetric method
SEM	AFM
EDS	VSI
XRD	Coronal and sagittal plane radiographs
Spectroscopy: AES, XPS, Raman spectroscopy, FTIR	2D-CT
-	3D-CT
-	SPECT

SEM: Scanning electron microscopy; EDS: Energy dispersive X-ray spectroscopy; XRD: X-ray diffractometry; AES: Auger electron spectroscopy; XPS: X-ray photoelectron spectroscopy; FTIR: Fourier transform infrared spectroscopic; AFM: Atomic force microscopy; VSI: Vertical scanning interferometer; 2D-CT: Two-dimensional computed tomography; 3D-CT: Three-dimensional computed tomography; SPECT: Single-photon emission computerized tomography.

Table 2 Studies analyzing the wear of retrieved total knee arthroplasty polyethylene components.

Number	Characteristic
1	Visual assessment of wear patterns, CMM
2	Surface laser profilometry
3	Laser scanner CMM
4	PE component thicknesses measurements using a dial indicator
5	Visual assessment of wear patterns, micro-CT
6	Volumetric wear analysis with micro-CT
7	Profilometry with a non-contact profilometer
8	PE component thicknesses measurements
9	Visual assessment of wear patterns, video microscopy, low-incidence laser CMM
10	Visual assessment of wear patterns, linear wear measurement with micro-CT
11	Visual assessment of wear patterns, topographical analysis
12	Laser scanner CMM
13	Raman spectroscopy
14	Calculation of wear based on the reference thickness of PE components with survival

CMM: Coordinate measuring machine; PE: Polyethylene; CT: Computed tomography.

GENERAL CONCEPTS

Mobile-bearing TKA has no surface damage advantage over fixed-bearing TKA

In a design-matched retrieval study Stoner et al[1] studied found no differences in polyethylene (PE) component wear damage between fixed-bearing PE components and mobile-bearing PE components in TKAs with similar condylar geometry.

Femoral components of cobalt-chromium roughens more than oxidized zirconium femoral components

In 2014, Heyse et al[2] analyzed retrieved oxidized zirconium (OxZr) femoral components and corresponding PE components. Heyse et al[2] reached the following conclusion: Cobalt-chromium (CoCr) roughens substantially more in situ compared with OxZr components. For Heyse et al[2] the clinical significance of their study was that bearing surfaces are usually damaged in vivo and that the degree of damage is variable between individuals and implants; nonetheless, rougher surfaces should be associated with more wear. Whether the differences found in this study prove meaningful needs long-run clinical data[2].

Minimal fixation is necessary for long-run success of TKA femoral components

Howard et al[3] analyzed the fixation of femoral components of TKA. The conclusion was that minimal fixation was necessary for long-run success of TKA femoral components.

In patients with varus-orientated osteoarthritis should the TKA be implanted in slight under-correction?

In 2015, Vandekerckhove et al found no difference in constrained revision between mild varus and moderate varus aligned TKAs[4].

Elevated tissue metal concentrations seem not to be associated with inflammatory cytokines

Arnholt et al[5] noticed raised cobalt, chromium and titanium concentrations in tissue retrieved TKAs. Therefore, it seemed that tissue metal concentrations were not related to inflammatory cytokines.

A correlation between increased posterior-stabilized coronal laxity and increased PE component wear seems to exist, but not in the posterior cruciate-retaining TKAs

In 2020, Perkins et al[6] stated that both posterior cruciate-retaining and posterior-stabilized (PS) TKAs have elevated success percentages and survivorship. Nevertheless, it was dubious how laxity and constraint were related to long-run PE component wear under physiological circumstances. This study suggested that a correlation exist between increased PS coronal laxity and increased PE component wear, but not in the posterior cruciate-retaining TKAs[6].

TKAs with central locking mechanisms are more likely to debond from their cement mantle than TKAs with peripheral locking mechanism

Bhalekar et al[7] studied whether wear and backside deformation of PE components might have an effect on the cement cover of tibial trays from explanted TKAs. It was found that TKAs with central locking mechanisms were more prone to debond from their cement mantle than TKAs with peripheral locking mechanism[7].

A combination of single photon emission computed tomography scan with a computed tomography scan can identify bone activity due to implant position and loading

Using single photon emission computed tomography scan with a computed tomography scan, Hothi et al[8] in 2022 found that the place (medial vs lateral) of bone tracer uptake pattern correlated with the deformation of PE components. Table 3 summarizes the main publications on general concepts in TKA[1-8].

Table 3 Main data on general concepts in retrieval analysis in total knee arthroplasty.

Ref.	Methods	Results	Conclusions
Stoner et al[1], 2013	These authors stated that rotating-platform TKA, although purported to have superior kinematics, had shown no clinical advantages over those of fixed-bearing TKA	Rotating-platform and fixed-bearing PE components had similar tibiofemoral damage scores. Besides, no differences were seen in the thicknesses between fixed- and rotating-platform PE components	No damage advantage to the mobile-bearing design was found
Heyse et al[2], 2014	Retrieved OxZr femoral components and corresponding PE components were examined to rule out patterns leading to early failure	Sixteen retrieved TKA were included. The prostheses were in situ for 16.4 months on average. There were no failures directly related to the implant	This study did not show major wear of the PE component in TKA using OxZr femoral components
Howard et al[3], 2014	This study analyzed the fixation for 19 non-revised, postmortem retrieved, femoral components of TKA with time in service ranging from 1 years to 22 years	The average initial interdigitation depth was 0.7 mm, and the average final interdigitation depth was 0.13 mm. Loss of interdigitation was 81%	Minimal fixation seemed necessary for long-term success
Vandekerckhove et al[4], 2015	Seventy-six retrieved PE components were analyzed for the RW, lateral lift-off and implications for future constrained revision surgery according to the coronal plane alignment	The RW significantly affected the coronal plane alignment in TKA However, there was no difference in constrained revision between mild varus and moderate varus aligned TKAs	Progressive wear and lateral lift-off were seen with progressive varus alignment
Arnholt et al[5], 2020	These authors tried to determine the preferred sampling location for tissue analysis in TKA and evaluate metal concentrations, inflammatory cytokines, component damage, and tissue metallosis	Increased Co was associated with decreased TNF-α and IL-1 beta. Increased Cr was associated with decreased TNF-α, IL-6, and MIP-3α	These authors observed elevated Co, Cr and Ti concentrations in tissue from necropsy-retrieved TKA
Perkins et al[6], 2020	These authors measured the laxity patterns of 47 harvested cadaver specimens with primary TKAs in a custom knee-testing machine at full extension and at 30°, 60°, and 90° of flexion. The wear patterns of the tibial inserts were assessed using a semiquantitative method which was a modified approach of that proposed by Hood et al in 1983	Statistical analysis found that the PS TKA cohort had a statistically significant increase in varus laxity at 60° and 90° of flexion, as well as total coronal laxity at 60° of flexion when compared to the posterior CR cohort	Whether a CR or PS TKA is used, surgeons need to avoid the pitfalls that may create greater flexion laxity during the procedure to optimize long-term PE component wear
Bhalekar et al[7], 2021	These authors investigated whether wear and backside deformation of PE components may influence the cement cover of tibial trays of explanted TKAs	The median planicity values of the PE components used with central locking trays were significantly greater than of those with peripheral locking PE components (205 microns vs 85 microns)	Explanted TKAs with central locking mechanisms were significantly more likely to debond from the cement mantle
Hothi et al[8], 2022	Retrieval analysis was performed with a micro-CT method to assess the thickness differences between medial and lateral sides of PE components with symmetrical designs. SPECT/CT was performed prior to revision. Quantitative and qualitative medio-lateral comparisons of BTU intensity and distribution in the tibia were performed	Patients showing a more extended BTU in the medial compartment also had a significantly thinner PE component in the medial compartment, and vice versa in the lateral side	This was the first study comparing BTU distribution patterns and retrieval findings

TKA: Total knee arthroplasty; RW: Ratio of wear; CT: Computed tomography; OxZr: Qxidized zirconium; SPECT: Single photon emission computed tomography; PE: Polyethylene; BTU: Bone tracer uptake; Co: Cobalt; TNF-α: Tumor necrosis factor alpha; IL: Interleukin; Cr: Chromium; MIP-3α: Macrophage inflammatory protein 3 alpha; PS: Posterior-stabilized; CR: Cruciate-retaining; Ti: Titanium.

PE COMPONENT

No major wear of the PE component in TKA using OxZr components has been found and polished tibial trays are advised

Heyse et al[9] did not encounter significant wear of the PE components in TKA utilizing OxZr components. Holleyman et al[10] advised the utilization of a polished tibial tray over an unpolished design.

Antioxidant-stabilized highly crosslinked PE component is not different in surface damage, density of crosslinking, or oxidation compared to standard remelted highly crosslinked PE components

Retrieval analysis of antioxidant-stabilized highly crosslinked PE components performed by Ponzio et al[11] in 2018 did not reveal a clinically relevant difference in surface damage, density of crosslinking, or oxidation compared with standard remelted highly crosslinked PE (XLPE) components at short-run assessment (15 months on average).

There is a correlation between implant position and PE component surface damage. Cerquiglini et al[12] found a substantial correlation between implant position and PE component surface damage. Characteristics of PS post fracture differ between XLPE and ultra-high-molecular-weight-PE components. In 2023 Kahlenberg et al[13] reported that the characteristics of PS post fracture differed between XLPE and ultra-high-molecular-weight-PE components. Table 4 summarizes main data on PE component wear in TKA[9-13].

Table 4 Main data on polyethylene component wear in retrieval analysis in total knee arthroplasty.

Ref.	Methods	Results	Conclusions
Heyse et al[9], 2011	These authors analyzed 16 retrieved TKA with an OxZr femoral component. The PE components were also analyzed applying an established scoring system for wear and surface damage	The average wear and damage score for the tibial PE components was 36. The average score in the visual analysis of the OxZr femoral components was 1.3	This study did not show major wear of the PE component in TKA using OxZr femoral components
Holleyman et al et al[10], 2015	These authors investigated the reciprocating interface at the TKA undersurface articulation using profilometry after in vivo service	Four pristine unimplanted components of two different designs (Stryker Kinemax and DePuy PFC) were examined for control purposes. Mean explant baseplate surface roughness was 1.24 μm. Mean explant UHMWPE component undersurface roughness was 1.16 μm	Findings of this study would support the use of a polished tibial tray over an unpolished design in TKA with the goal of reducing PE component wear by means of providing a smoother backside countersurface for the UHMWPE component
Ponzio et al[11], 2018	These authors evaluated the surface damage, the density of crosslinking, and oxidation in retrieved A-XLPE components from TKA and compared the results with a matched cohort of XLPE components	A-XLPE components had higher rates of burnishing and lower rates of pitting and scratching compared with XLPE components	Retrieval analysis of A-XLPE did not reflect a clinically relevant difference in surface damage, density of crosslinking, or oxidation compared with XLPE components at short-term evaluation
Cerquiglini et al[12], 2018	This study correlated highly accurate CT measurements of pre-revision TKA implant position with findings of retrieval analysis post-revision, to understand the clinical relevance of TKA orientation	There was a significant correlation between tibial slope and damage score on PE components as well as a significant correlation between implants’ position in the axial plane and damage score on PE components	A significant correlation between implant position and PE component surface damage was found. These results showed the importance of optimizing component position to minimize PE component damage
Kahlenberg et al[13], 2023	These authors evaluated the PE component and patient characteristics for 33 primary PS, PE components that were revised with fractured posts: UHMWPE vs the XLPE (highly cross-linked PE) component	Total surface damage scores were higher in the UHMWPE component group vs the XLPE component group	Characteristics of PS post fracture differed between XLPE and UHMWPE components, with fractures occurring in the XLPE component with less generalized surface damage, after a shorter LOI, and with SEM evaluation indicative of a more brittle fracture pattern

TKA: Total knee arthroplasty; OxZr: Qxidized zirconium; PE: Polyethylene; A-XLPE: Antioxidant-stabilized highly crosslinked polyethylene; XLPE: Standard remelted highly crosslinked polyethylene; CT: Computed tomography; PS: Posterior stabilized; UHMWPE: Ultra-high-molecular-weight-polyethylene; LOI: Length of implantation; SEM: Scanning electron microscopy.

SOME SPECIFIC PROSTHETIC DESIGNS

Titanium PFC Sigma implants vs CoCr PFC Sigma implants, vs CoCr PFC Sigma rotating platform implants vs Attune implants. In 2019 Cerquiglini et al[14] reported that most initial PFC Sigma designs showed evidence of cement, while all of the retrieved Attune trays and the majority of the rotating platform PFC trays had no cement attached. Modern knee tumor megaendoprostheses have considerable volumetric metal wear generated at the rotating hinge. In 2020 Bormann et al[15] in 2020 found an elevated wear score of two or greater was encountered in 43% of individuals. Persona TKA vs NexGen TKA: In 2021 Mathis et al[16] reported that surface damage was not different between Persona TKA and NexGen TKA. The earlier failure rate with Optetrak Logic PS TKA is of concern. Malahias et al[17] in 2022 reported that the use of the Optetrak Logic PS TKA femoral component was related to early aseptic loosening. Table 5 summarizes the main data of the publications analyzed in this article on some specific designs of TKA[14-17].

Table 5 Main data on some specific designs in retrieval analysis in total knee arthroplasty.

Ref.	Methods	Results	Conclusions
Cerquiglini et al[14], 2019	These authors examined 12 Ti PFC Sigma implants, eight CoCr PFC Sigma implants, eight cobalt-chromium PFC Sigma RP implants, and 11 Attune implants	There was no evidence of cement attachment on any of the 11 Attune trays examined. There were significant differences between Ti and CoCr PFC Sigma implants and Attune designs	The majority of the earliest PFC Sigma designs showed evidence of cement, while all of the retrieved Attune trays and the majority of the RP PFC trays in this study had no cement attached
Bormann et al[15], 2020	In this study, wear volume and influencing parameters were investigated at 44 retrieved TKAs with MoM couplings	An elevated wear score of two or higher was found in 43% of cases. A tendency for higher wear scores with higher inlay degradation scores was found	The generated wear volume was high
Mathis et al[16], 2021	These authors investigated the in vivo performance of a new design (Persona), by comparing it with its predecessor (NexGen) in retrieval analysis	The Persona tibial tray showed a significantly smoother surface (0.06 μm) compared to the NexGen (0.2 μm)	The bonding of the antioxidant vitamin-E to the PE component chain used in the novel Persona knee system does not reduce in vivo surface damage compared to highly crosslinked PE component without supplemented vitamin-E used in its predecessor knee system NexGen
Malahias et al[17], 2022	This study examined if the use of the Optetrak Logic PS femoral component was associated with early and more extensive aseptic loosening compared with other PS femoral components. Sixteen individuals received the Optetrak Logic PS femoral component (group A), while 11 received other PS femoral components (group B)	A significant difference was found in presence of backside femoral burnishing between group A (15 of 16 patients; 93.8%) and group B (5 of 11 patients; 45.6%)	The earlier failure rate with the Optetrak Logic PS femoral component was of concern

TKA: Total knee arthroplasty; Ti: Titanium; CoCr: Cobalt-chromium; RP: Rotating platform; MoM: Metal-on-metal; PS: Posterior stabilized; PE: Polyethylene.

LIMITATIONS

Cerquiglini et al[12] encountered a significant correlation between implant position and PE component surface damage. This finding should influence clinical practice. Correct component position is paramount to reduce PE damage[12]. Retrieval analysis has some limitations, such as the challenge of correlating in vivo and ex vivo findings. Other limitations of current literature on TKA retrieval analysis are firstly that most studies have a small sample size. Secondly, primary TKAs were carried out by different orthopedic surgeons, which can produce a vast diversity of causes for failure and, thus, revision of the prostheses. A limitation of this article is that only PubMed was used and no other databases (EMBASE, Scopus, etc). Future research directions should explore how TKA design improvements could diminish wear and how technological innovations can increase the accuracy and reproducibility of retrieval analysis. No bias or conflict of interest was detected during the literature review of retrieval analysis in TKA.

CONCLUSION

The following conclusions of clinical interest can be drawn from the analysis of the literature on retrieval analysis in TKA: (1) There is a correlation between implant position and PE component surface damage. It shows the importance of optimizing component position to reduce PE component damage; (2) Regarding surface damage, rotating-platform (mobile-bearing) TKA has no advantage over fixed-bearing TKA; (3) TKAs with central locking mechanisms are more prone to debond from the cement mantle; (4) No major wear of the PE in TKA using OxZr components occurs; (5) Femoral components of CoCr roughen more than OxZr femoral components; (6) The use of a polished tibial tray over an unpolished design is advised; (7) At short-run assessment, antioxidant-stabilized highly crosslinked PE component is not clinically different in surface damage, density of crosslinking, or oxidation compared to XLPE component; and (8) Contemporary knee tumor megaendoprostheses show notable volumetric metal wear originated at the rotating hinge.