Survivorship, complications, and outcomes following distal femoral arthroplasty for non-neoplastic indications

Abstract

Aims: Endoprosthetic reconstruction with a distal femoral arthroplasty (DFA) can be used to treat distal femoral bone loss from oncological and non-oncological causes. This study reports the short-term implant survivorship, complications, and risk factors for patients who underwent DFA for non-neoplastic indications.

Methods: We performed a retrospective review of 75 patients from a single institution who underwent DFA for non-neoplastic indications, including aseptic loosening or mechanical failure of a previous prosthesis (n = 25), periprosthetic joint infection (PJI) (n = 23), and native or periprosthetic distal femur fracture or nonunion (n = 27). Patients with less than 24 months' follow-up were excluded. We collected patient demographic data, complications, and reoperations. Reoperation for implant failure was used to calculate implant survivorship.

Results: Overall one- and five-year implant survivorship was 87% and 76%, respectively. By indication for DFA, mechanical failure had one- and five-year implant survivorship of 92% and 68%, PJI of 91% and 72%, and distal femur fracture/nonunion of 78% and 70% (p = 0.618). A total of 37 patients (49%) experienced complications and 27 patients (36%) required one or more reoperation. PJI (n = 16, 21%), aseptic loosening (n = 9, 12%), and wound complications (n = 8, 11%) were the most common complications. Component revision (n = 10, 13.3%) and single-stage exchange for PJI (n = 9, 12.0 %) were the most common reoperations. Only younger age was significantly associated with increased complications (mean 67 years (SD 9.1)) with complication vs 71 years (SD 9.9) without complication; p = 0.048).

Conclusion: DFA is a viable option for distal femoral bone loss from a range of non-oncological causes, demonstrating acceptable short-term survivorship but with high overall complication rates. Cite this article: Bone Jt Open 2022;3(3):173-181.

Keywords: Distal femoral replacement; Distal femur; Fracture; Mechanical failure; Megaprosthesis; Periprosthetic joint infection; Total joint; Trauma; aseptic loosening; distal femoral fractures; femoral arthroplasty; femoral bone loss; mechanical failure; nonunion; periprosthetic distal femur fractures; periprosthetic joint infection (PJI); reoperations; wound complications.

Fig. 1

Kaplan-Meier survival curve for all patients’ status post-distal femoral arthroplasty for non-oncological indications, with endpoint of time until first reoperation for implant revision (95% confidence interval 7.73 to 9.97).

Fig. 2

Kaplan-Meier survival curve for patients status post-distal femoral arthroplasty for non-oncological indications, subdivided by initial indication for megaprosthesis, with endpoint of time until first reoperation for implant revision. Patients with an original indication of mechanical failure (n = 25): 95% confidence interval (CI) 5.28 to 9.96; periprosthetic joint infection (PJI) (n = 23): 95% CI 7.50 to 11.8; and trauma (n = 27): 95% CI 6.11 to 9.64.

Fig. 3

Kaplan-Meier survival curve for all patients status post-distal femoral arthroplasty for non-oncological indications, with endpoint of time until first reoperation for any cause (95% confidence interval 5.81 to 8.66).

Fig. 4

Kaplan-Meier survival curve for patients status post-distal femoral arthroplasty for non-oncological indications, subdivided by initial indication for megaprosthesis, with endpoint of time until first reoperation for any cause. Patients with an original indication of mechanical failure (n = 25): 95% confidence interval (CI) 4.60 to 8.81; periprosthetic joint infection (PJI) (n = 23): 95% CI 6.08 to 10.9; and trauma (n = 27): 95% CI 4.67 to 8.57.

Fig. 5

Pre- and postoperative anteroposterior radiographs of a 60-year-old female with prior total knee arthroplasty (2009) and periprosthetic joint infection (PJI) and revision (2010) presenting with a) imaging of her existing total knee arthroplasty. b) Six years after the revision knee arthroplasty and multiple failed antibiotic courses for recurrent methicillin-sensitive Staphylococcus aureus PJI, the implant was explanted and an antibiotic cement spacer was placed. c) Four months later she underwent distal femoral arthroplasty (DFA). d) Due to suspected ongoing PJI she then underwent a polyethylene exchange and irrigation and debridement three weeks later. e) Without resolution of the PJI, she underwent DFA explantation and placement of antibiotic spacer after another two months and, lastly, f) after an additional three months she underwent arthrodesis of the right knee. There have been no signs of PJI since fusion.