Replacement of carpal bones with exact-fitting silicone rubber implants. An experimental study

Orthopedic interventions often require replacement of damaged or removed bone structures. Prior research has shown that implant materials must balance durability with biocompatibility. No prior work had resolved the issue of exact anatomical fit in bone replacement. This gap motivated the development of a method to create implants that match the excised bone's shape. The challenge lies in achieving a precise fit while using materials that cure quickly. Traditional methods may not allow for rapid fabrication and sterilization. The need for a one-stage procedure increases surgical efficiency. This study aimed to address these limitations in veterinary orthopedics.

The goal was to test a method for replacing carpal bones in dogs using custom-fitted silicone implants. The study aimed to evaluate the feasibility of a one-stage surgical approach. A key problem was the time required for implant curing. The motivation was to reduce the risk of implant misalignment. The researchers proposed using silicone rubber for its flexibility and moldability. The study intended to assess both material suitability and surgical outcomes. The focus was on achieving rapid fabrication and implantation. The aim was to improve accuracy and reduce complications in bone replacement.

Six dogs underwent carpal bone excision followed by implantation. Implants were made from two silicone materials: MDX-4-4210 and Silastic 399. Bone cement was used to create casts of the excised bones. Molds were made using alginate or plaster of Paris. The fabrication process required precise replication of the bone shape. Implants were sterilized before surgical insertion. The procedure was designed to be completed in a single operation. Postoperative follow-up ranged from one to seven months.

Silastic 399 was found to cure rapidly and was suitable for the study. MDX-4-4210 required five hours to cure, even with external heating. Five out of six dogs had satisfactory outcomes after implantation. One dog experienced postoperative infection, leading to an unsatisfactory result. Implants were fabricated and inserted within one to two hours. The method allowed for exact reproduction of the excised bone. Implant rotation and migration were minimized due to the precise fit. The results suggest the method is effective in most cases.

The method allows for exact reproduction of the excised bone structure. The use of Silastic 399 enabled rapid fabrication and implantation. The one-stage procedure reduced surgical time and potential complications. The results suggest the method is generally effective in veterinary orthopedics. The risk of implant rotation was minimized due to the precise fit. The researchers propose that this approach could be adapted for human use. The study highlights the importance of material selection in implant surgery. The findings suggest that exact fitting improves surgical outcomes.