Does Unicondylar Knee Arthroplasty Affect Tibial Bone Strain? A Paired Cadaveric Comparison of Fixed- and Mobile-bearing Designs

Abstract

The institution of one or more of the authors (GP, OT, JS, BV, HvL and LS) has received, during the study period, funding and material support by Zimmer-Biomet and the European Knee Society Research Award, 2016. The funders have no role in the study design, data collection, and analyses. Each author certifies that neither he or she, nor any member of his or her immediate family, have funding or commercial associations (consultancies, stock ownership, equity interest, patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article. However, one of the authors certifies that he (TH), or a member of his or her immediate family, has received or may receive payments or benefits, during the study period,

Assessment of in vivo bone activity patterns in medial mobile-bearing unicompartmental knee arthroplasty

“…[4][5][6] The main cause for revision surgery, apart from progression of OA in the native compartments, is aseptic loosening and persistent, unexplained pain. 4,[7][8][9][10] Although associated with different underlying aetiologies, both complications are thought to be the consequence of an aberrant mechanical bone-prosthesis interaction, [10][11][12] resulting in higher bone strains, which is suggested by several experimental studies as a possible cause for persistent pain and discomfort. [8][9][10][12][13][14][15][16] In an attempt to identify these failing UKAs, single proton emission CT (SPECT)/CT imaging has been proposed as a diagnostic imaging technique.…”

“…4,[7][8][9][10] Although associated with different underlying aetiologies, both complications are thought to be the consequence of an aberrant mechanical bone-prosthesis interaction, [10][11][12] resulting in higher bone strains, which is suggested by several experimental studies as a possible cause for persistent pain and discomfort. [8][9][10][12][13][14][15][16] In an attempt to identify these failing UKAs, single proton emission CT (SPECT)/CT imaging has been proposed as a diagnostic imaging technique. 17 SPECT/CT can visualize the expected higher osteoblastic bone turnover around UKA components from the continuous increased osteogenic adaptive bone response to the altered, aberrant bone strains.…”

“…Finally, we investigated the evolution of the osteoblastic bone activity in specific cortical regions, previously suggested as the possible origin of pain after medial UKA based on experimental, in vitro data. [8][9][10][12][13][14][15][16]19 they provided, prior to the first SPECT/CT examination, signed informed consent. An a priori analysis (G*Power 3.1.7; University of Düsseldorf, Germany) was performed to determine the appropriate sample size based upon the bone tracer changes reported in our previous SPECT/CT study.…”

“…20 We chose to specifically target tibial volume of interest zones (VOIs) adjacent to the joint line, as prior experimental research identified the tibial bone-prosthesis interface and direct underlying bone as areas of interest. [8][9][10][11][12][13][14][15][16] With specific reference from the anterior (Na) and posterior (Np) native tibial VOIs (Figure 1), 19 and 18 patients, respectively, would be required to reach a power of 90% (α = 0.05, effect size 0.82) in both fixation cohorts. After consulting 75 patients (80 knees), 40 UKAs performed in 36 patients could be included, with bilateral UKAs being carried out in a sequential setting (Figure 2).…”

“…In addition, a more comprehensive approach was used to evaluate the osteoblastic bone activity in specific cortical zones, identified by previous experimental research as possible locations subjected to aberrant bone strains. 26 Anteromedial and posterior cortical zones [8][9][10][12][13][14][15][16]19 were reviewed using a previously developed and validated SPECT/CT registration platform (SCreg) 26 (Figure 5) in a subset (23 UKAs) of the complete cohort. Statistical analysis.…”