20 - 3D-printed hallux and lesser metatarsophalangeal joint replacement

Abstract

The application of 3D printing in foot and ankle surgery such as hallux and lesser metatarsophalangeal joint (MTPJ) replacement has gained in popularity recently due to advancements in technology and surgical techniques. Custom/patient-specific hemiarthroplasty has been successfully implemented to improve pain and maintain range of motion, most commonly in hallux and lesser MTPJ arthritis. Indications include MTPJ arthritis as well as avascular necrosis and failed synthetic cartilage implant. Traditional surgical treatments for hallux and lesser MTPJ arthritis have their own advantages and disadvantages, but consideration of 3D-printed hemiarthroplasty should be given for the appropriate patient and clinical situation. Advantages of patient-specific implants compared to standard implants include matching the patient’s anatomy as well as multiple different-sized implants to allow for intraoperative variability. Cobalt chromium is typically used due to its wear resistance, and a gyroid porous structure is used for bony ingrowth with press-fit implants. These can be locked proximally as well as cemented as needed for additional fixation. In the senior author’s experience, there have been no periprosthetic fractures, radiographic evidence of subsidence, osteolysis, nor implant loosening. Patient selection is very important for consideration of hemiarthroplasty and they should be appropriately counseled regarding potential complications from hemiarthroplasty such as periprosthetic fracture as well as need for compliance with low-impact activity restrictions.