Summary

Knee arthrodesis without bone fusion, using modular intramedullary nails and a cement block as a spacer, is a salvage procedure in periprosthetic joint infection with severe bone defects, lack of soft tissue coverage, and inadequate infection control.

Abstract

Introduction

Periprosthetic joint infection is a complication that can lead to severe bone defects, lack of soft tissue coverage, and inadequate infection control. Knee arthrodesis without bone fusion, using modular intramedullary nails and a cement block as a spacer, is a salvage procedure in these situations, serving as an alternative to limb amputation.

Objective

To analyze the quality of life of patients undergoing knee arthrodesis with modular intramedullary nails. To evaluate implant survival and associated complications.

Materials And Methods

A retrospective cohort study involved 34 patients treated with knee arthrodesis using an intramedullary nail as definitive treatment for periprosthetic infection between 2015 and 2023 at a single institution. The minimum follow-up period was set at one year.
Demographic characteristics of our series were evaluated, including clinical aspects, risk factors, and reasons for the indication of nail fixation surgery. The patient's quality of life was evaluated using the Oxford Knee Score (OKS). The Kaplan-Meier method was used to estimate the cumulative incidence of implant loss. Orthopedics complications and the proportion of patients who achieved healing from infection, according to Laffer criteria, were recorded.

Results

At the one-year follow-up after surgery, a quality of life score of 32 (SD 12) was reported, considered moderate to good, with an implant survival rate estimated by the Kaplan-Meier method of 77% (CI 56-88%). The average number of surgeries before arthrodesis was 9 (range from 6 to 12), and the average number of surgeries with previous prosthetic reimplantation was 3 (range from 2 to 5). A total of 46.4% of patients required a soft tissue flap. In 88.2% of cases, a modular intramedullary nail was chosen as the implant. Severe bone defects classified as AORI 3 were detected in all cases except one. After reconstruction, the average limb length discrepancy was 28 mm. A complication rate of 35% was recorded, which included 6 amputations, 3 nail replacements due to persistent infection, and 3 implant failures. The most common primary pathogen was methicillin-sensitive Staphylococcus aureus. The infection healing rate in the series was 56.5%.

Conclusion

The knee arthrodesis procedure is a safe alternative salvage procedure for recurrent periprosthetic infections. This technique allows for early ambulation, without significant loss in the length of the lower limb. However, unlike previous studies, our series demonstrated higher rates of reinfection, as well as a decrease in implant survival rates.