Knee fusion using sign nail, an addition to the armamentarium: Technique and outcome

Abstract

Background: Knee arthrodesis still has indications in this modern era of arthroplasty and ranges from failed total knee arthroplasty, advanced tuberculous infection to severe contractures. Of the implants that can be used for knee fusion, intramedullary devices have the lowest rates of major complications, shortest time to fusion and the highest fusion rates.
Objective: To describe the results and technique of a case series of knee fusions performed using SIGN nails at AIC Kijabe Hospital, Kenya.
Design: A retrospective case series.
Methods: This case series describes a novel implant choice for knee fusion in eight patients. Of the eight patients, six were male and two were female. The average age was 40 years. They were followed up for an average of 13 months. All the surgeries were performed by a single surgeon and utilised the same technique. Outcome was based on assessment for clinical and radiologic union.
Results: Four (50%) of the arthrodeses were secondary to advanced tuberculous infection, one was due to chronic knee dislocation and three were due to failed total knee replacement. Seven (87.5%) went on to primary union. One (12.5%) patient needed bone grafting and dynamization and 2(25%) sustained a peri-prosthetic fracture. All patients are ambulant with no weight-bearing restrictions.
Conclusion: The SIGN intramedullary nail system allows an easy and reproducible knee fusion technique in resource and equipment limited settings. Our case series demonstrated that the knee fusion with the SIGN nail lead to successful union in majority of our patients. In addition, 25% of our patients developed a periprosthetic fracture at the nail insertion site which has not been reported in other similar studies.

Key words: Knee, Arthrodesis, Fusion, SIGN nail, Infection