Introduction: This study was undertaken to investigate the incidence and to identify predictors of physiologic remodeling in the medial aspect of the proximal tibia in varus knees after total knee arthroplasty (TKA).
Materials and methods: One hundred and sixty-six consecutive patients (221 knees) who underwent navigation-assisted TKA and were followed for a minimum of 2 years were included. Changes in bone radiolucency in the medial aspect of the proximal tibia on the radiographs were investigated at each follow-up. All information on potential factors affecting medial tibial remodeling were retrieved and classified as being patient-, radiography-, or surgery-related.
Results: Radiographic change of bone stock in the medial aspect of the proximal tibia was observed in 18 % of knees (39/221). In all of these cases, this was first detected within 3 months after surgery. During the initial phase to 3 months after surgery, bone stock radiolucency typically increased, but then gradually decreased and after 1 year postoperatively, radiolucency no longer changes with time. Of the 15 variables analyzed, the difference between medial extension gap after bone cutting and prostheses thickness was found to be significantly associated with occurrence of radiographic change of bone stock.
Conclusion: In some varus knees showing physiologic bone remodeling in the medial aspect of the proximal tibia after TKA, prostheses thickness showed a strong tendency to be larger than the medial extension gap after bone cutting.