Abstract
Purpose of the study
This study was undertaken to evaluate the early results of a new implant system - the metaphyseal sleeve - in revision total knee replacement. The femoral and tibial metaphyseal sleeves are a modular option designed to deal with metaphyseal bone loss and achieve cementless fixation over a relatively wide area in the metaphysis.
Methods
Over three years, femoral and/or tibial metaphyseal sleeves were implanted in 104 knees in 103 patients (54 male and 49 female). The clinical notes and radiographs of these patients were reviewed retrospectively. Thirty one patients had revision for infection, 42 for aseptic loosening, and 31 for instability, pain or stiffness. Eighty nine knees were revised as a single stage and 15 were done as two stage procedure. Minimum follow up is 12 months (average 18.5 months).
Results
At the time of final follow up the sleeves showed good osseointegration in 102 knees with no evidence of loosening or subsidence. In two knees, a progressive radiolucency was noted around the metaphyseal sleeve 6 months after the revision procedure. Both these patients were symptomatic. The inflammatory markers were raised and Tc-99 bone scan showed increased uptake in the delayed phase. Loosening of the sleeve was confirmed on CT scans. SPECT scan raised suspicion of focal infection around the sleeve in one patient.
Conclusion
The early results with the use of metaphyseal sleeves are encouraging. The sleeves provided firm fixation and structural support in patient with significant metaphyseal bone loss. This obviated the need for metal augments or bone graft. Further follow up will be required to evaluate the medium and long term results of this option. We believe the addition of cementless metaphyseal fixation is a useful tool in the armamentarium of the revision knee surgeon.
