TY - JOUR

T1 - Preoperative proximal tibial bone density, bone microarchitecture, and bone turnover are not associated with postoperative tibial component migration in cemented and cementless medial unicompartmental knee replacements

T2 - secondary analyses from a randomized controlled trial

AU - Bendtsen, Mathias Alrø Fichtner

AU - Odgaard, Anders

AU - Madsen, Frank

AU - Mosegaard, Sebastian Breddam

AU - Thomsen, Jesper Skovhus

AU - Hauge, Ellen Margrethe

AU - Søballe, Kjeld

AU - Stilling, Maiken

N1 - Publisher Copyright: © 2024 The Author(s). Published by MJS Publishing – Medical Journals Sweden, on behalf of the Nordic Orthopedic Federation.

PY - 2024

Y1 - 2024

N2 - Background and purpose — Cementless arthroplasty fixation relies on early bone ingrowth and may be poor in patients with low proximal tibial bone density or abnormal bone turnover. We aimed first to describe the baseline bone properties in patients undergoing medial unicompartmen-tal knee replacement (UKR), and second to investigate its association with cemented and cementless tibial component migration until 2 years. Methods — A subset investigation of 2 patient groups from a 3-armed randomized controlled trial was conducted. There were 26 cemented and 25 cementless medial UKRs with twin-pegged femoral components. Volumetric bone mineral density (vBMD) and microstructure of the excised medial tibial plateau were ascertained with µCT. Bone turnover was estimated using dynamic histomorphometry (eroded surface/bone surface = ES/BS, osteoid surface/bone surface = OS/BS, mineralizing surface/bone surface = MS/ BS). Tibial component migration in 4 feature points was followed for 2 years with radiostereometry. Results — At the 2-year follow-up, the cementless tibial components migrated 0.38 mm (95% confidence interval [CI] 0.14–0.62) total translation more than the cemented components at the posterior feature point. The greatest migration in the cementless group was subsidence at the posterior feature point of 0.66 mm (CI 0.48–0.84) until 6 weeks, and from 3 months the components were stable. Cemented tibial components subsided very little. Between 1-and 2-year follow-ups, no cementless but 4 cemented tibial components revealed continuous migration. OS/BS was half of the ES/BS. No µCT or histomorpho-metric parameters showed any clinically relevant correlation with tibial component migration at the posterior feature point for either cemented or cementless UKR at 6 weeks’ or 2 years’ follow-up after adjustment for age, BMI, and sex. Conclusion — Preoperative vBMD, bone turnover, and microstructure were not associated with postoperative tibial component migration of cemented and cementless medial UKR.

AB - Background and purpose — Cementless arthroplasty fixation relies on early bone ingrowth and may be poor in patients with low proximal tibial bone density or abnormal bone turnover. We aimed first to describe the baseline bone properties in patients undergoing medial unicompartmen-tal knee replacement (UKR), and second to investigate its association with cemented and cementless tibial component migration until 2 years. Methods — A subset investigation of 2 patient groups from a 3-armed randomized controlled trial was conducted. There were 26 cemented and 25 cementless medial UKRs with twin-pegged femoral components. Volumetric bone mineral density (vBMD) and microstructure of the excised medial tibial plateau were ascertained with µCT. Bone turnover was estimated using dynamic histomorphometry (eroded surface/bone surface = ES/BS, osteoid surface/bone surface = OS/BS, mineralizing surface/bone surface = MS/ BS). Tibial component migration in 4 feature points was followed for 2 years with radiostereometry. Results — At the 2-year follow-up, the cementless tibial components migrated 0.38 mm (95% confidence interval [CI] 0.14–0.62) total translation more than the cemented components at the posterior feature point. The greatest migration in the cementless group was subsidence at the posterior feature point of 0.66 mm (CI 0.48–0.84) until 6 weeks, and from 3 months the components were stable. Cemented tibial components subsided very little. Between 1-and 2-year follow-ups, no cementless but 4 cemented tibial components revealed continuous migration. OS/BS was half of the ES/BS. No µCT or histomorpho-metric parameters showed any clinically relevant correlation with tibial component migration at the posterior feature point for either cemented or cementless UKR at 6 weeks’ or 2 years’ follow-up after adjustment for age, BMI, and sex. Conclusion — Preoperative vBMD, bone turnover, and microstructure were not associated with postoperative tibial component migration of cemented and cementless medial UKR.

U2 - 10.2340/17453674.2024.39917

DO - 10.2340/17453674.2024.39917

M3 - Journal article

C2 - 38391197

AN - SCOPUS:85185971150

VL - 95

SP - 121

EP - 129

JO - Acta Orthopaedica

JF - Acta Orthopaedica

SN - 1745-3674

ER -