Validation of a computer‐assisted method for measurement of radiographic wear in total hip arthroplasty using all polyethylene cemented acetabular components

Abstract

Although cemented all polyethylene (PE) cups have been routinely used in total hip arthroplasty for decades, no computer-assisted method for measurement of radiographic wear has ever been specifically validated for these implants. Using a validated hip phantom model, AP plain hip radiographs were obtained consecutively for eight simulated wear positions. A version of Martell's Hip Analysis Suite software dedicated to all polyethylene sockets was used by three different examiners of varied experience. Bias (mean, standard deviation and 95% confidence interval limit), repeatability (standard deviation and 95% limit) and reproducibility (standard deviation and 95% limit) for two-dimensional wear measurements were assessed, as recommended by the current ASTM guidelines. Using this protocol, the dedicated software showed an overall mean bias of 0.089 AE 0.060 mm (mean AE SD), and 0.118 mm for 95% CI limit. Repeatability (intra examiner) standard deviation and 95% limit were respectively 0.106 mm and 0.292 mm. Reproducibility (inter examiner) standard deviation and 95% limit were respectively 0.112 mm and 0.308 mm. Martell Hip Analysis for all PE cemented cups is a reliable and low-cost instrument in the assessment of wear, despite being less precise than its original version dedicated to cementless components. Keywords: total hip replacement; polyethylene wear; error measurement; precision measurement; accuracy measurementThe number of total hip arthroplasty (THA) surgical procedures in the United States is expected to reach 572,000 per year by the year 2030.1 As this procedure is getting more and more reliable, an increasing number of younger patients are now THA candidates. However it has been shown that this population might present accelerated polyethylene wear. To solve this problem, many refinements in polyethylene (PE) processing have been proposed including cross-linking with or without the addition of an anti-oxidant such as vitamin E.2 These have showed excellent results in hip simulator studies and in clinical practice, leading to a continued interest in using PE in THA. In addition, there is increasing recent evidence that cemented fixation of acetabular components might be more reliable than that of cementless components beyond the first postoperative decade. 3,4 This phenomenon could be related to accelerated PE wear in uncemented compared to cemented acetabular components. 5As polyethylene wear remains a major factor in failure of THA through particle-induced osteolysis and resultant aseptic loosening, 6 new challenges for in vivo measurement of wear in THA implants are a matter of major concern. Indeed, wear measurement is critical to adequately evaluate new materials and can also help to decide when to monitor patients more closely and when to consider revision surgery. Though various radiographic methods have been developed to measure polyethylene wear, including manual or computerassisted plain radiography, two-or three-dimensional techniques, or radiostereometric analysis, 7,8 to the bes...

Do Oxidized Zirconium Femoral Heads Reduce Polyethylene Wear in Cemented THAs? A Blinded Randomized Clinical Trial

“…First, the Hip Analysis Suite software dedicated to all-polyethylene sockets has lower reproducibility and repeatability with larger bias when compared with the original version for cementless sockets. However, it has been recently demonstrated that precise data also could be obtained with this version [16]. It should however be acknowledged that the detection limits of the current version of the Martell method were close to our results.…”

“…In the HXLPE series, the median steady-state penetration rate from 1 year onward was 0.02 mm/year (range, À0.32 to 0.07 mm/year) in the oxidized zirconium group versus 0.05 mm/year (range, À0.39 to 0.11 mm/year) in the metal group (difference of medians 0.03, p \ 0.001). The Merle d'Aubigné scores were no different between the groups with a median of 18 in each of the groups (range, [16][17][18]. Conclusions This study demonstrated femoral head penetration was reduced by oxidized zirconium when compared with metal on both UHMWPE and HXLPE.…”

“…The median value Merle d'Aubigné hip score at the latest followup was 18 in each of the four study groups (range, [16][17][18] with no difference with the number available (p = 0.64). There were likewise no differences in terms of the qualitative ratings of the scores (p = 0.84); of the 43 hips in the UHMWPE series with complete followup, 29 hips were rated excellent, 12 hips as very good, one hip as good, and one hip as poor.…”

“…In the current study, we used a specific version of the Martell software dedicated to all-polyethylene cups that has been recently validated according to the ASTM standards [16]. It has a mean bias of 0.089 ± 0.060 mm, a mean repeatability of 0.106 ± 0.292 mm, and a mean reproducibility of 0.112 ± 0.308 mm.…”

Radiostereometric analysis using clinical radiographic views: Validation measuring total hip replacement wear

“…Repeatability and average error (also termed bias), along with more historically termed values of precision and accuracy, were calculated in the manner of Langlois et al who followed the latest ASTM standards for terminology . Repeatability and average error were evaluated for both penetration approaches, that is, femoral head versus acetabular cup and femoral head versus liner markers, and compared between our novel and conventional RSA procedure.…”