Influence of Implant Design and Individual Joint Laxity on In Vivo Medio-Lateral Stability of the Knee

Kreangsak Lekkreusuwan1 , Wolfgang Scior2 and Heiko Graichen2*

Phramongkutklao College of Medicine, Thailand 2 Centre of Arthroplasty; Orthopedic Hospital Lindenlohe, Germany

^*Correspondance to: Heiko Graichen 

 PDF  Full Text DOI: 10.25107/2474-1647.3050

Abstract

Background: There are different factors that influence medio-lateral joint stability; implant design and individual joint laxity being two of them. In this study, we assessed the in vivo effect (1) of implant conformity and (2) of individual patient laxity on medio-lateral stability by comparing 2 implants in different flexion angles. Methods: 129 patients were treated with TKA between May to August 2014; 67 in Group A (Attune, DePuy-Synthes) and 62 in Group B (P.F.C. DePuy-Synthes). Dynamic stability testing was performed with navigation (Knee3, Brainlab). Medial and lateral gap values were recorded and compared statistically in 5-degree steps of flexion, starting at extension to maximum flexion. Subgroup analysis of individual laxity was performed in the different implant groups. Patients were divided in 3 subgroups (1=tight: 5 mm) based on individual pre-OP laxity. Results: Group A showed a reduced gap opening on the medial side in all flexion angles, the difference being significant between 5? to 85? and at 135?. For the lateral gap there were no significant differences. Subgroup analysis showed an increased medial stability in all flexion angles for tight knees (subgroup 1). In contrast to that, subgroup 3 showed no significant difference between implants. Conclusion: In this study we could quantify for the first time in vivo, that implant conformity and individual laxity are relevant factors for ml stability in TKA. While in tight knees both factors work additive, in lax knees the effect of implant design is dominated by laxity.

Keywords

Total Knee Arthroplasty; In vivo stability; Navigation; Dynamic stress testing; Conformity; Laxity

Cite the article

Lekkreusuwan K, Scior W, Graichen H. Influence of Implant Design and Individual Joint Laxity on In Vivo MedioLateral Stability of the Knee. Clin Surg. 2021; 6: 3050..