JOA - 2026-06-10 - Journal Article
The "Distal Femoral Replacement Downgrade": Technique of Using Bicondylar Femoral Cones with a Hinge Total Knee Arthroplasty Revision in Patients Who Have Massive Distal Femoral Bone Loss as an Alternative.
Chalmers BP, Afzal S, Bhatti P, Anatone AJ, Blevins JL, Debbi EM, Sculco PK, Gausden EB
Topics
Key Takeaway
Bicondylar femoral cone-hinge construct ('DFR downgrade') achieved 100% survivorship free from aseptic loosening and 85.1% survivorship free from any re-revision at one and two years in 20 patients with AORI IIB/III femoral bone loss.
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Summary
This study evaluated a bone-preserving alternative to distal femoral replacement (DFR) in revision TKA patients with severe femoral bone loss (60% AORI III, 30% AORI IIB), pairing bicondylar metadiaphyseal-engaging femoral cones with a hinged construct. At mean 14.5-month follow-up, aseptic loosening-free survivorship was 100% and any re-revision-free survivorship was 85.1% at one and two years. Three reoperations occurred: one periprosthetic fracture revised to DFR, one PJI managed with two-stage revision, and one patellar button exchange for implant recall.
Key Limitation
The mean follow-up of 14.5 months is critically short to draw conclusions about cone osseointegration, aseptic loosening, or long-term survivorship in a population with massive bone loss.
Original Abstract
BACKGROUND
Massive femoral bone loss with collateral insufficiency in revision total knee arthroplasty (TKA) is often managed with distal femoral replacement (DFR), but this procedure sacrifices bone stock and carries notable risks. We described outcomes of a bone-preserving alternative (the "DFR downgrade") that pairs bicondylar, metadiaphyseal-engaging femoral cones with a hinge construct.
METHODS
We performed a retrospective review of consecutive patients who underwent revision TKA using a "DFR downgrade" technique for severe femoral bone loss between February 2016 and July 2024. There were twenty patients (mean age, 69 years (range, 58 to 86); 65% men) included, with a mean follow-up of 14.5 months (range, 0.9 to 43.7). Indications were aseptic loosening in 75%, infection in 10%, ligamentous instability in 10%, and arthrofibrosis in 5%. Demographics, Anderson Orthopaedic Research Institute (AORI) classification, operative details, postoperative complications, and clinical and radiographic outcomes were collected. The Kaplan-Meier method was used to estimate reoperation-free and re-revision-free survivorship. Femoral bone loss was classified as AORI IIA in 10%, IIB in 30%, and III in 60% of cases.
RESULTS
Survivorship free from revision for aseptic loosening was 100% at one and two years. Survivorship free from any re-revision was 85.1% at one and two years. Survivorship free from any reoperation was also 85.1% at one and two years. There were three knees that required reoperation: one for a periprosthetic femoral fracture revised to a DFR; one for infection treated with two-stage revision and reimplantation of a DFR downgrade construct; and one for patellar button exchange after an implant recall.
CONCLUSIONS
In patients who have severe femoral bone loss and condylar compromise, a "DFR downgrade" consisting of a bicondylar cone-hinge construct achieved favorable survivorship. While further study is warranted, this appears to be a pragmatic, bone-preserving alternative to DFR.