Limitations of Structural Allograft in Revision Total Knee Arthroplasty

Abstract

Management of large bone defects in total knee arthroplasty (TKA) usually has involved modular prostheses with metal augments, structural allografts, and megaprostheses. We retrospectively reviewed the outcome of treatment of major bone defects for 74 patients (79 knees) who had revision TKAs with structural allografts; nine patients were lost to followup before 5 years, leaving 65 patients (70 knees, or 88%) followed for a minimum of 5 years or until revision or death. Medical records, radiographs, patient surveys, and correspondence were used for all data. Sixteen patients (22.8%) had failed reconstructions and underwent additional revision surgery; eight of the 16 were secondary to allograft failure, three were secondary to failure of a component not supported by allograft, and five were secondary to infection. In patients not requiring revision surgery, the Knee Society score improved from 49 preoperatively to 87 postoperatively. We observed revision-free survival of 80.7% (95% confidence interval, 71.7-90.8) at 5 years and 75.9% (95% confidence interval, 65.6-87.8) at 10 years. Our data support the selective use of structural allograft for large cavitary defects encountered during TKA. However, the rates of complications and reoperations suggest efforts to improve results or develop more durable alternative methods are warranted for these challenging reconstructions.

Tantalum Cones Provide Durable Mid-term Fixation in Revision TKA

“…Furthermore, in our cohort, 13 of the 18 revisions were second-stage reimplantations for deep infection and yet, at this longer followup, had an infection rate comparable to those in the other reports. Our data compare unfavorably with the infection frequencies reported in the bulk allografts studies [1,6,11]. Bauman et al [1], Engh and Ammeen [11], and Chun et al [6] reported infection rates of 7% (five of 70), 4% (two of 46), and 4% (one of 27) respectively in their series.…”

“…Our data compare unfavorably with the infection frequencies reported in the bulk allografts studies [1,6,11]. Bauman et al [1], Engh and Ammeen [11], and Chun et al [6] reported infection rates of 7% (five of 70), 4% (two of 46), and 4% (one of 27) respectively in their series. However, only 9% to 11% of these reconstructions with bulk allografts were reimplantations for infection, whereas in our study 13 of the 18 revisions were second-stage reimplantations for deep infection.…”

“…Bauman et al [1], Engh and Ammeen [11], and Chun et al [6] reported reoperation rates of 23% (16 of 70), 19% (nine of 46), and 0% (0 of 27) in their series of 70, 46, and 27 knees respectively at minimum 5 years followup. Our revision frequency compares favorably with the reoperation frequencies reported by Bauman et al [1] and Engh and Ammeen [11], but unfavorable with the rate reported by Chun et al [6].…”

“…Studies with structural allografts and tumor megaprostheses during revision knee arthroplasty have reported encouraging mid-term results, but the high number of complications is a concern. Complications with these techniques include infection, graft resorption, nonunion, failure of graft incorporation, concerns regarding disease transmission, aseptic loosening, and periprosthetic fracture [1,7,14,17,33]. Although the short-term results with tantalum cones have been promising [9,18,21,23,24,26,[34][35][36]42], to our knowledge, there have been no studies reporting mid-term outcomes with their use.…”

“…Major tibial and femoral bone defects, classified as Anderson Orthopaedic Research Institute (AORI) [10] Types 2B and 3, have been reconstructed using impaction bone grafting with or without mesh augmentation [22,25,38,40,44], structural or bulk allografts [7,11,14,16,17,28,31,39], modular metal augmentations of prostheses [15,32], and tumor-type megaprostheses [2]. Studies using structural allografts have reported numerous complications and minimum 5-year survivorship of 67% to 96% [1,6,7,14,17], whereas reconstructions with tumor-type megaprostheses have shown a 5-year survivorship of 68% [33]. Although there have been studies reporting encouraging mid-term results with these treatment options [6,43], the best method has not been established [10].…”