Early Results with the Use of Synthetic Cartilage Implant Augmented with 3D Printed Baseplate to Prevent Implant Subsidence for Treatment of Hallux Rigidus

Abstract

Category: Midfoot/Forefoot Introduction/Purpose: Hallux rigidus (HR) of the first metatarsophalangeal joint (MTPJ) is a common arthritic disease which causes pain and stiffness. Synthetic cartilage implant (SCI) resurfacing has become a popular treatment option since it has similar biomechanical properties as native cartilage, reduces pain, and preserves MTPJ motion. However, recent studies have reported on implant subsidence leading to SCI treatment failure and subsequent revision surgery. A novel solution involves proximally inserting a custom 3D printed baseplate in the metatarsal head to prevent SCI subsidence. The purpose of this study is to evaluate the clinical and radiographic outcomes of patients who underwent SCI resurfacing augmented with a 3D printed beasplate for the treatment of HR by a single surgeon. Methods: Electronic health records were queried from August 2017 to August 2021 for patients who were treated with SCI (Cartiva Synthetic Cartilage Implant; Cartiva Inc., Alpharetta, GA) augmented with a custom 3D printed baseplate by a single surgeon. Through a dorsal approach to the MTPJ, the custom 3D printed baseplate is inserted in the metatarsal head and the SCI implant is positioned two millimeters proud from the cortex. An akin osteotomy is then performed and fixed with a staple. For the study, surgical indications included symptomatic HR and revision of previously failed SCI treatment. Patient demographics, body mass index (BMI), medical comorbidities, and followup periods were recorded. Preoperative and postoperative range of motion, visual analog scale (VAS) pain scores, and x-ray imaging were compared. Descriptive and univariate statistics were used to analyze data. Results: Twenty-one patients underwent SCI resurfacing augmented with a 3D printed baseplate. The cohort consisted of 18 females, and presented with a mean BMI of 30.4+-5 Kg/m2, mean age of 56.4+-10 years, and mean followup of 9.8+-13 months since the procedure. Patients experienced a significant improvement in VAS pain (P=0.002) scores. The SCI augmented with 3D printed baseplate survivorship was 90.4%, with only two (9.5%) patients requiring revision to first MTPJ arthrodesis for SCI subsidence and sesamoidal arthritis. Two (9.5%) patients additionally underwent reoperation for staple removal and infection. The first MTPJ space was maintained on x-ray imaging for 19 (90.5%) patients, with only two (9.5%) patients demonstrating implant subsidence. Conclusion: SCI resurfacing augmented with a custom 3D printed baseplate demonstrated significant improvements in pain and prevented implant subsidence in patients suffering from symptomatic HR. Future prospective studies should be performed to expand upon the clinical outcomes data analyzing this novel technique to prevent SCI subsidence in the treatment for HR.