Abstract
Introduction
When using press-fit stems in revision total knee arthroplasty (TKA), diaphyseal engagement optimizes stability. Attempts to maximize press fit may lead to periprosthetic fracture; however, the literature offers no guidance regarding the prevalence or management of this complication. The purpose of this study is to report the incidence, risk factors, and outcomes of these fractures.
Methods
634 Stemmed implants (307 femoral and 327 tibial) from 413 consecutive revision TKAs were reviewed. Immediate and 6 week post-operative radiographs were examined. Patient age, gender, stem length, diameter, and offset were evaluated as potential risk factors for fracture occurrence using a paired t-test for continuous and a chi-square analysis for categorical variables.
Results
15 Periprosthetic fractures (2.4%) were identified including two femoral (0.65%) and 13 tibial (4.0%). 10 Fractures were non-displaced, 3 had cortical displacement <2mm, and 2 were displaced >2mm. 1 Femur fracture was recognized and fixed intra-operatively with cables. 11 patients with non or minimally displaced fractures were allowed to bear weight as tolerated and 2 were protected for 2 weeks. 1 Displaced fracture was braced for 3 months, while the other was casted for concomitant extensor allograft reconstruction. All fractures showed radiographic evidence of healing and all patients were able to painlessly bear weight within 6 months. There was no evidence of implant migration at a mean of 15 months (range 3-47 months). 1 Patient developed recurrent infection at 10 months; no other complications were identified. With the sample size available for study, no significant differences in age (p=0.09), implant parameters (p=0.06-0.85) or gender (p=0.37) were detected between the fracture and non-fracture groups.
Conclusions
Periprosthetic fractures occurred in approximately 2.4% of press-fit stems in revision TKA, more commonly in the tibia than femur. All fractures were managed non-operatively without complication or loss of prosthetic fixation.
