In vivo wear measurement in a modern total knee arthroplasty with model-based radiostereometric analysis

Abstract

Aims A retrospective study was conducted to measure short-term in vivo linear and volumetric wear of polyethylene (PE) inserts in 101 total knee arthroplasty (TKA) patients using model-based radiostereometric analysis (MBRSA). Patients and Methods Nonweightbearing supine RSA exams were performed postoperatively and at six, 12, and 24 months. Weightbearing standing RSA exams were performed on select patients at 12 and 24 months. Wear was measured both linearly (joint space) and volumetrically (digital model overlap) at each available follow-up. Precision of both methods was assessed by comparing double RSA exams. Patient age, sex, body mass index, and Oxford Knee Scores were analyzed for any association with PE wear. Results Linear wear occurred at 0.015 mm/year (supine) and 0.220 mm/year (standing). Volumetric wear occurred at 10.3 mm3/year (supine) and 39.3 mm3/year (standing). Wear occurred primarily on the medial side of the joint. Weightbearing imaging greatly improved the reliability of measurement. Clinical precision of volumetric wear was 34 mm3. No significant associations were found between patient demographics or function scores and measured wear. Conclusion In vivo volumetric wear of TKAs can be assessed at short-term follow-up using MBRSA. Cite this article: Bone Joint J 2019;101-B:1348–1355.

Five-year migration and insert wear of uncemented tibial components with either conventional polyethylene or sequentially annealed highly crosslinked polyethylene inserts: a blinded randomized controlled trial using radiostereometric analysis

“…This observation is in line with an earlier study that also showed that most wear occurs on the medial side. 30 The lateral wear for both insert groups is negative. This 'negative' wear is most likely explained by movement of the Table IV.…”

“…This observation is in line with an earlier study that also showed that most wear occurs on the medial side. 30…”

Model-Based Roentgen Stereophotogrammetric Analysis Using Elementary Geometrical Shape Models: Reliability of Migration Measurements for an Anatomically Shaped Femoral Stem Component

“…Classical marker-based RSA or mbRSA approach offers the opportunities: to measure in vivo implant fixation [43,44], to investigate, e.g., new THA design or coatings, degenerative changes [45][46][47], joint kinematics [48] and pathomechanism [49], and bony fusion [50]. Additionally, it offers the opportunity to investigate the effect of joint material connection within total joint arthroplasty, likewise the head-taper junction [17].…”

Roentgen stereophotogrammetric analysis: still a very valuable tool in the orthopaedic research armamentarium

“…4,21,28 Other potential applications of RSA include in vivo linear and volumetric wear using model-based radiostereometric analysis. [29][30][31][32][33] Gascoyne et al 30 used modelbased RSA to evaluate linear and volumetric polyethylene (PE) wear in 101 TKA patients. Consecutive, precise measurements of joint space distance in supine and weightbearing positions were used as a surrogate for determining linear polyethylene (PE) wear, while volumetric wear was measured following the introduction of the computer-aided design (CAD) model and assessment of the degree of overlap between the PE component and femoral condyles.…”

“…Consecutive, precise measurements of joint space distance in supine and weightbearing positions were used as a surrogate for determining linear polyethylene (PE) wear, while volumetric wear was measured following the introduction of the computer-aided design (CAD) model and assessment of the degree of overlap between the PE component and femoral condyles. 30 Similarly, RSA was used in another study to measure the in vivo wear of different bearing types of the Oxford unicompartmental knee replacement. The linear distance between the tibial tray and femoral prosthesis was calculated and subtracted from the estimated bearing thickness.…”