Prospective insights into tibial stems, cemented versus uncemented in primary total knee arthroplasty: A dual‐energy X‐ray absorptiometry study

TL;DR

This study compares bone density changes around cemented and noncemented tibial stems in knee replacement surgery, finding that cemented stems better preserve bone density over time.

Contribution

The study provides new empirical evidence on the long-term periprosthetic bone mineral density outcomes of cemented versus noncemented tibial stems in primary TKA.

Findings

Cemented stems showed greater BMD gains compared to noncemented stems at 12 and 24 months.

Cemented stems demonstrated higher BMD retention compared to noncemented stems.

Minimal changes in BMD were observed in both groups, but cemented stems performed better.

Abstract

The durability and effectiveness of total knee arthroplasty (TKA) depend on secure implant fixation and efficient bone integration. While cemented tibial components provide immediate mechanical stability, the addition of a short stem may be indicated in selected cases to enhance fixation. However, the stem does not allow for biological integration. The advantages of cementation over press‐fit fixation remain a subject of debate, particularly regarding their impact on periprosthetic bone mineral density (BMD) over time. This study aims to compare periprosthetic BMD changes between cemented and noncemented tibial stems in primary TKA.

In this prospective, monocentric study, we compared periprosthetic BMD changes in 60 patients undergoing primary TKA, randomised into two groups: 30 with cemented and 30 with noncemented tibial stems. Dual‐energy X‐ray absorptiometry (DEXA) measured BMD preoperatively and at 3, 6, 12 and 24 months postoperatively across six zones: beneath the tibial tray (R1, R2), around the stem (R3, R4), at the apex (R5), and a control zone below the stem (R6). Statistical analyses included repeated measures analysis of variance and independent t‐tests.

Cemented stems showed a significant increase in BMD at 12 months (+0.10 g/cm², p = 0.03) and 24 months (+0.12 g/cm², p = 0.04), outperforming noncemented stems (+0.06 g/cm², p = 0.12). Overall, cemented stems demonstrated greater BMD gains (+0.15 g/cm² vs. +0.08 g/cm², p = 0.03). Minimal changes were observed in both groups, with cemented stems showing slightly higher BMD retention (+0.05 g/cm² vs. −0.02 g/cm², p = 0.09). No statistically significant differences were recorded in certain regions.

Cemented stems demonstrated greater periprosthetic BMD retention, which may contribute to improved mechanical environment for the implant. These findings may help guide the selection of fixation methods in primary TKA, particularly for patients with compromised bone quality.

Level I.

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