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 135 primary cemented tka in 131 patients over three years. we compared demographics, serial radiographs, and early clinical and functional outcomes. results: there were 65 tkas (48%) in 62 patients who had rlls within the first year post-operatively. most were females (58.8%). mean age was 68.3 ± 7.9 years. there were 88 rlls, with the most and second commonest location at the medial tibial baseplate (38%) and anterior femoral flange (23%). 89% were in the bone-cement interface. the largest average length of rlls were at the anterior flange of the femoral component (1.98 ± 1.33 mm). the average time to development was 6.5 ± 4.1 months. none of these patients had infections nor required revision. patients with rlls did not do worse in functional and clinical scoring at 1-year. conclusion: there was a 48% incidence of physiological rlls after cemented tka, with the highest occurrence at the medial tibial baseplate at 38%. these radiolucent lines did not affect early post-operative clinical and functional outcomes of patients.