Purpose: The rate of failure knee arthrodesis can be high when performed after an infectious complication of a total knee arthroplasty. We evaluated, in 14 patients at a mean 19 months (3–44 months) follow-up, a technique for knee arthrodesis using a custom-made endomedullary implant.
Material and methods: Mean age of these eight women and six men was 68 years. There were 11 patients with an infected prosthesis, one with post-trauma arthritis, one with aseptic loosening of a hinge prosthesis, and one with pseudarthrodesis. For the 12 patients with ongoing infection, surgery was performed in two times with insertion of a spacer (with antibiotics) between the operations. Mean delay between the two operations was 18 weeks. The surgical procedure was associated with a two-drug antibiotic regimen given for a mean three months after arthrodesis. All arthrodeses were stabilised with a custom-made femora-tibial implant with reaming and fixation with two screws. A graft was always used, composed of the reaming products and powder bone substitute in seven cases, reaming products alone in three, and bone-bank heads in four.
Results: Morbitiy: There was one misalignment of the tibial insertion that was not revised. One skin cover problem was treated with a vastus medius flap. One nonunion evolved favourably after a new graft. There were two recurrent infections: chronic fistulae that were controlled by local care and adapted antibiotic therapy. Weight-bearing was started during the first postoperative week in 13 patients. Bone healing (assessed radiographically with resolution of pain) was achieved at a mean three months (2–6 months) in 13 cases. At last follow-up all patients had achieved a satisfactory level of independence.
Discussion: According to the literature, intramedullary devices are superior for consolidating knee arthrodeses, with a lower rate of complications. Use of custom-made endo-medullary implants facilitates the operation and assures better stabilisation of the arthrodesis, allowing rapid weight-bearing. The infection must be controlled before using these implants. The results in our patients are in agreement with the most recent series reported (Barry, Stephen, Kuoan).
Conclusion: In our hands, this type of implant provides an effective means of attaining bony fusion, including in patients who require arthrodesis for an infected prosthesis.