Incidence of Radiolucent Lines after Cemented Total Knee Arthroplasty

Background: Cemented Total Knee Arthroplasty (TKA) provides excellent long-term survival rates and functional results, however, radiolucent lines (RLLs) often appear during early post-operative follow-up and their incidence and clinical significance are unknown. The primary aim was to establish the incidence, location, frequency, and time taken for RLLs to appear within the first year after a primary cemented TKA with an anatomic tibial baseplate (Smith and Nephew, LEGION Total Knee System). Methods: This was a retrospective analysis of ۱۳۵ primary cemented TKA in ۱۳۱ patients over three years. We compared demographics, serial radiographs, and early clinical and functional outcomes. Results: There were ۶۵ TKAs (۴۸%) in ۶۲ patients who had RLLs within the first year post-operatively. Most were females (۵۸.۸%). Mean age was ۶۸.۳ ± ۷.۹ years. There were ۸۸ RLLs, with the most and second commonest location at the medial tibial baseplate (۳۸%) and anterior femoral flange (۲۳%). ۸۹% were in the bone-cement interface. The largest average length of RLLs were at the anterior flange of the femoral component (۱.۹۸ ± ۱.۳۳ mm). The average time to development was ۶.۵ ± ۴.۱ months. None of these patients had infections nor required revision. Patients with RLLs did not do worse in functional and clinical scoring at ۱-year. Conclusion: There was a ۴۸% incidence of physiological RLLs after cemented TKA, with the highest occurrence at the medial tibial baseplate at ۳۸%. These radiolucent lines did not affect early post-operative clinical and functional outcomes of patients. Level of evidence: III

Keywords:

Radiolucency , Total knee arthroplasty , Total knee replacement , Cemented