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Poor Clinical Outcomes Following Total Knee Arthroplasty-Associated Revisions of Extensor Mechanism Allograft
Yifan V Mao1, Charlotte F Wahle1, Matthew V Dipane1
1Department of Orthopaedic Surgery, David Geffen School of Medicine at UCLA, Los Angeles, California.
Background:
Extensor mechanism rupture following total knee arthroplasty is a formidable complication frequently limiting limb function. Multiple reconstruction techniques are described, but the extensor mechanism allograft (EMA) that is utilized for complex reconstruction has notable failure rates. Rarer is a second attempt at EMA reconstruction. The outcomes of these revised EMA reconstructions have not been well studied. We report our outcomes with a revised EMA procedure.
Methods:
Revision EMA reconstructions performed between November 2018 and August 2023 were retrospectively reviewed. All EMA reconstructions utilized fresh-frozen, nonirradiated allografts from the Musculoskeletal Transplant Foundation. Inclusion criteria were a failed extensor reconstruction with a prior EMA, infection-free, and functional debility with clinical falling. Patients were graded according to the McPherson host and limb score. There were 17 revision EMA reconstructions performed in 17 patients, 10 of whom were women, who had a mean age of 67 years. There were 10 uncompromised A host and 14 who had a limb score of 3 (highly compromised).
Results:
There were 13 revision EMAs that failed among the 17 reconstructions, 10 of which underwent additional operations. There were three considered clinical failures with a Knee Injury and Osteoarthritis Outcome Score, JR. score < 63.7 points, and five patients who had a lag > 30°. There were three patients who were revised for mechanical EMA failure (tear/rupture). There were five patients who were revised due to chronic periprosthetic joint infection with all undergoing a two-stage exchange protocol. There were eight patients who were eventually revised to a third EMA.
Conclusions:
A second revision EMA reconstruction exhibits high failure rates with poor clinical outcomes, related to failure of allograft incorporation, early mechanical allograft failure, and chronic periprosthetic joint infection. Alternative techniques for extensor reconstruction are needed. In patients who had a compromised limb, bracing may be the best alternative solution.
Level Of Evidence:
4, Retrospective review of consecutive case series.
