Abstract
Introduction
Revision TKA can be a difficult and complex procedure. Bone quality is commonly compromised and stem fixation is required in many cases to provide stability of the prosthetic construct. However, utilization of diaphyseal engaging stems adds complexity to the case and can present technical challenges to the surgeon. Press fit metaphyseal sleeves can provide stable fixation of the construct without the need for stems and allows for biologic ingrowth of the prosthesis. Metaphyseal sleeves simplify the revision procedure by avoiding the need to prepare the diaphysis for stems, alleviating the need for offset stems and decreasing the risk of intra-operative complications. The ability to obtain biologic fixation in the young patient is also appealing. This study reports on the author's mid-term experience with this novel technique.
Methods
Between May 2007 and June 2009 the author performed 17 revisions TKA that utilized press-fit metaphyseal sleeves without stems on either the tibial side of the joint, the femoral side of the joint or both. Twenty six sleeves were implanted altogether (13 tibial, 13 femoral). Patients were limited to touch down weight bearing for 6 weeks post-operatively. The patients were followed prospectively with clinical and radiographic follow-up at routine intervals.
Results
Average clinical and radiographic F/U for the cohort was 57 months (range 30 – 77). Fourteen of seventeen patients had a minimum of 4 years F/U. Average age at the time of surgery was 58 years (range 46–72) and average BMI was 32.4. Indications for the index revision included nine knees with aseptic loosening and / or osteolysis, two knees for septic loosening, two knees for instability and 4 knees for pain / stiffness or other causes. ROM at pre-op and latest F/U averaged 2–108 deg and 0–117 deg respectively. Knee Society Scores at pre-op and latest F/U averaged 35 and 86 respectively (range 57–100). Survivorship analysis revealed 25 of 26 sleeves (96%) to still be in situ at latest F/U. One tibial sleeve was revised at 30 months for septic loosening. Radiographic analysis revealed 22 of the remaining 25 sleeves (88%) to be ingrown. Two tibial sleeves and one femoral sleeve exhibit stable fibrous fixation and are asymptomatic.
Conclusions
Press-fit metaphyseal sleeves utilized without stems appear to provide excellent stability of the revision TKA construct at mid-term F/U. Biologic fixation appears to be present in the majority of cases. This ability to obtain reliable osseointegration of the revision construct is appealing, especially in the younger revision patient. The sleeves have proven easy to use and there have been no intra-operative complications. This technique appears to provide a simple, but robust alternative when compared to revision TKA with stems in appropriate cases. Further F/U of this cohort is necessary to evaluate long term results.
