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UK hospital reports encouraging outcomes at 16 months for metaphyseal sleeves
Short-term patient results give surgeons long-term optimism.
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SAN DIEGO – Researchers reported encouraging early results from a prospective study on the use of porous-coated metaphyseal sleeves in revision total knee arthroplasty (TKA) at this year’s American Academy of Orthopaedic Surgeons meeting.1
Rohit Maheshwari, FRCS, from the National Health Service’s (NHS) Fife Hospitals in the United Kingdom, was on hand to deliver his group’s outcomes.
“There was no osteolysis, loosening or subsidence between the metaphyseal sleeve and the host bone contact interface,” Maheshwari said. “[The sleeves] provide a strong foundation by compression of the metaphyseal bone in a step manner,” he added (Figure 1).
Methods
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From June 2008 through August 2009, Maheshwari and his team performed 20 revision surgeries comprised of 11 women and nine men with an average age of 73.5 years. Aseptic loosening was the primary cause for revision in 19 patients, and one patient underwent single-stage revision for infection.
Bone defects were classified intraoperatively using the Anderson Orthopaedic Research Institute system and found that a majority of defects in the femur and tibia were type 2B (19 and nine, respectively), and nine were type 1.
Outcomes
Patients were assessed 16 months postoperatively using clinical and radiological assessments. Nineteen patients achieved full extension and their average range of motion (ROM) was 0° to 95°. One patient was treated with antibiotics for a superficial wound infection, while another had an immediate postoperative myocardial infarction and sustained lateral dislocation of the patella in the critical care unit. As a result, he was not medically fit to undergo any further surgery to his knee. However, he remains pain-free postoperatively with a ROM of 50° to 80°.
In a patient satisfaction survey, 16 patients reported having a “good” or “excellent” recovery, while four patients reported a “fair” recovery with mild to moderate pain.
“So far, we have not done any re-revisions,” Maheshwari said.
Regarding radiological outcomes, Maheshwari’s team observed a mean neutral mechanical axis of 5° valgus and no evidence of osteolysis, loosening or subsidence.
“Nineteen patients achieved full extension and their average ROM was 0° to 95°.”
— Rohit Maheshwari, FRCS
Maheshwari discussed several case studies to show patients’ improvement. One patient, a 76-year-old man, presented with aseptic loosening 14 years after primary total knee replacement (TKR). Surgeons revised the knee using metaphyseal sleeves for an uncontained defect and the postoperative X-ray showed satisfactory alignment of the sleeves and components (Figure 2).
A second patient, a 69-year-old woman, presented with an infected TC3 revised total knee. She underwent a single-stage revision using metaphyseal sleeves. The postoperative radiograph showed an uncontained defect in the medial tibial plateau that was not supported with structural allograft. Maheshwari’s team performed a single-stage revision and used a long stem to bypass the diaphyseal defect (Figure 3). The tibial metaphyseal sleeves provided support at the lateral tibial condyle. This patient is doing well and shows no sign of infection at her last follow-up.
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Conclusion
According to Maheshwari, orthopedic surgeons across the United Kingdom performed approximately 4,000 knee revisions in 2008. As revision surgeries become more common, surgeons will need more options that provide long-term stable fixation. With the positive short-term outcomes found in this study, Maheshwari is optimistic about long-term results. “These sleeves provide mechanical support for both tibial and femoral components, and therefore, have the potential for providing long-term biological fixation.”
References
- Maheshwari R, Ahmed I, Sabnis B, Walmsley P, Brenkel I. Use of porous stepped metaphyseal sleeves during revision total knee arthroplasty. Paper presented at: American Academy of Orthopaedic Surgeons 2011 Annual Meeting; February 15-19, 2011; San Diego.
Rohit Maheshwari, FRCS, has no direct financial interest in the products discussed in this article, nor is he a paid consultant for any companies mentioned.