Influence of the tibial stem design on bone density after cemented total knee arthroplasty: a prospective seven-year follow-up study

Abstract

We prospectively measured the changes in bone mineral density (BMD) in the proximal tibia of 20 total knee arthroplasties, ten with cruciform stems and ten with cylindrical stems. The measurements were made one, four and seven years after surgery. We observed a uniform density decrease in three regions of interest from one to seven years of follow-up. Cylindrical stems showed an asymmetrical density decrease between the three regions of interest, with no change in the central region, a slight decrease in the lateral region, and large decrease in the medial region. Multivariate analysis with general linear model showed the stem type factor as statistically significant for medial region of interest (p=0.006). The cylindrical stem produces heterogeneous BMD changes under the tibial platform in knee arthroplasties, and this could be a potential risk factor for asymmetrical subsidence of this component. Résumé Nous avons de façon prospective mesuré les modifications de la densité minérale osseuse (BMD) au niveau de la partie proximale du tibia chez 20 patients ayant bénéficié d'une prothèse totale du genou, 10 avec une quille cruciforme et 10 avec une quille cylindrique. Les mesures ont été réalisées de 1.4 à 7 ans après l'intervention chirurgicale. Nous avons observé une diminution uniforme de la densité minérale osseuse dans trois zones, durant cette période de 1 à 7 ans de suivi. La quille cylindrique montre que la densité minérale osseuse diminue de façon asymé-trique dans ces 3 régions sans modification au niveau de la région centrale, avec une légère diminution de la région externe (latérale) et une diminution plus importante de la région interne (médiale). Une analyse de régression multi variable montre que le type de quille est l'élément le plus significatif au niveau de la région interne (p=0.006). La quille cylindrique étant un facteur statistiquement significatif et entraînant des modifications hétérogènes de la BMD, sous le plateau tibial. Ces modifications peuvent être un risque potentiel de migration du composant tibial.

Clinical value of SPECT/CT in the painful total knee arthroplasty (TKA): a prospective study in a consecutive series of 100 TKA

“…It was found that cylindrically shaped short stems lead to an asymmetrical tibial decrease in bone density after TKA [39]. A slight decrease laterally, an insignificant decrease centrally and a large decrease medially was seen [39]. The authors concluded that this could lead to medial subsidence of the tibial TKA component [39].…”

“…A slight decrease laterally, an insignificant decrease centrally and a large decrease medially was seen [39]. The authors concluded that this could lead to medial subsidence of the tibial TKA component [39]. A major limitation of this study was that TKA position was not assessed.…”

“…It was found that in the longer stemmed group the metaphyseal bone density was significantly reduced, which is due to stress shielding and consequent proximal bone resorption [38]. It has also been postulated that the design of the tibial short stem (cruciform versus cylindrical) influences bone remodelling after TKA [39]. It was found that cylindrically shaped short stems lead to an asymmetrical tibial decrease in bone density after TKA [39].…”

“…It has also been postulated that the design of the tibial short stem (cruciform versus cylindrical) influences bone remodelling after TKA [39]. It was found that cylindrically shaped short stems lead to an asymmetrical tibial decrease in bone density after TKA [39]. A slight decrease laterally, an insignificant decrease centrally and a large decrease medially was seen [39].…”

Bone mineral density changes of the proximal tibia after revision total knee arthroplasty. A randomised study with the use of porous tantalum metaphyseal cones

“…A decrease in BMD is often observed after immobilisation and reduced mobility, after ankle fractures, tibia shaft fractures and a postoperative decrease in BMD ranging from nearly unchanged to 27 % have been measured one year after TKA [10,20,21], THA [22] and osteotomy of the tibia [23].…”