Local design and manufacturing of patient-specific implant using Anatomage Medical Design Studio software: proof of concept - Botswana's 1st case report

Abstract

Background: Botswana, like most sub-Sahara African nations, uses conventional orthopaedic implants that are sourced from major manufactures in the West. The implants are mass-produced and designed with universal configurations to fit an average patient. During surgery, surgeons thus sometimes bend the implants to match the individual bone anatomy, especially for paediatric patients and those with unique deformities, thus risking implant failure. The purpose of this project was to show the feasibility of developing safe and effective patient-specific orthopaedic implants in a low-resourced market.

Methods: CT Scan slice files of a paediatric patient with Ollier's disease were used to reconstruct the lower limb anatomy. The resultant files were 3D printed into prototypes that showed severe right knee valgus deformity. The surgeon used the prototype to plan for corrective femoral osteotomy and the required implant. The implant design and planned surgery were subsequently simulated on the Medical Design Studio software for proper fitting before final implant printing. Surgery was then performed, followed by 12 weeks of physiotherapy.

Results: Post-surgical x-rays demonstrated good implant positioning and knee joint alignment. At 18 months of post-surgical follow-up, the child was pain-free, could perform full squats, and ambulation was near-normal, without the use of an assistive device.

Conclusions: It is feasible to develop effective, patient-specific implants for selected orthopaedic cases in a low-resourced country. This work could improve surgical and rehabilitation outcomes for selected paediatric patients and those with severe bone deformities.

Keywords: 3D printing; Achilles tendon lengthening; Medical design studio; Ollier’s disease; Patient-specific implant; Post-operative knee rehabilitation.

Fig. 1

A) Pre-surgery CT scan of patient, B) Anatomage MD Studio anatomical models of the defect area, and C) 3D printed prototype model of the anatomical defect

Fig. 2

A) Surgical plan by surgeon using Coreldraw, B) Desired implant design concept by surgeon

Fig. 3

Images ABC show simulation of surgical plan on Anatomage MD studio

Fig. 4

3D models of implant

Fig. 5

Simulation of implant fit to deformity correction site on Anatomage MD studio

Fig. 6

Implant (Grade23 Titanium-6-Al-4-V) and drill guide received from CUT

Fig. 7

Images A-E illustrating surgical procedure using developed drill guide and implant

Fig. 8

Image of the 3D-printed prototype illustrating ripple-like effects and hollow areas

Fig. 9

A) graph and table presentation of mechanical properties conducted on the destructive test samples, B) CT scan of implant showing no microcracks after post processing

Fig. 10

Image of final implant after post processing

Fig. 11

X-ray image of implant positioning right after surgery showing excellent fit