Peking University Third Hospital: Follow-Up of 92 Consecutive Patients with 3D Printed Titanium Acetabular Cups

Researchers from Peking University Third Hospital have released the findings of a recent study in ‘A new 3D printing porous trabecular titanium metal acetabular cup for primary total hip arthroplasty: a minimum 2-year follow-up of 92 consecutive patients.’

For this study, the authors worked with 92 consecutive patients from 2013-2017, analyzing clinical data of patients with 3D printed cementless acetabular cups inserted during total hip arthroplasties. Follow-ups averaged just over 48 months. The overall aim of the study was to find out the outcomes as well as satisfaction levels from patients after THA with the 3D printed titanium cups.

3D printing has become much more commonplace in the medical industry today, and especially in regards to medical implants—from craniofacial implants to titanium mandibular implants and devices meant to improve knee arthroplasties.

The picture shows the 3D ACT EBM-produced trabecular titanium acetabular cup (a) and the SEM image of its cellular solid structure (b)

During this clinical study for arthroplasty patients, three patients died of cancer, while eight were lost in the follow-up process before two years had passed.

“None of these 11 patients were deceased due to THA associated diseases or underwent revision until our last evaluation,” stated the authors.

TThe picture shows the interface between the two layers of traditional cup (Left) and the integration EBM porous structure (Right).

A total of 40 males and 52 females participated, agreeing to a two- to six-year follow-up time. The cups were inserted with 1 mm press-fit technology. While there were no intraoperative complications, the authors noted several ‘considerably tough cases.’ All cups did continue to offer ‘good primary stabilities’ post-implantation, however.

Only two patients said that they were dissatisfied. The cup ‘survival rate’ was 100 percent, with no revisions for patients. All cups showed ‘excellent osseointegration.’

“The manufacturing process of 3D printing acetabular cup is completely different from that of traditional cups,” stated the researchers. “In traditional reduction casting process, the interface between the solid layer and the coated surface of the acetabular cups may cause detachment and corrosion, resulting to cup failures. But 3D printing, via additive manufacturing process, has made it easier to individualize product design and manufacturing.”

The success of the study—and the EBM-produced cups—was attributed to a rougher surface, also featuring a greater coefficient of friction on cancellous bone. The implant is also porous, solid, and imitates true trabecular morphology.

“This study does have several limitations,” concluded the researchers. “First, in this retrospective study, 11/103 of the patients lost to follow up. Second, no controlled groups enrolled in this study, and we are about to carry out a prospective randomized controlled trial for higher-level evidence. Third, cases from 6 different surgeons enrolled which may confound the results. Fourth, computer tomography (CT) scans and bone densitometry evaluations as well as relevant laboratory examinations were not conducted.

“As far as be concerned, the application of EBM-produced 3D ACT cup demonstrated us its favorable short to mid-term clinical outcomes in Chinese THA patients. It can provide high acetabular cup survival rate, great clinical improvements, and excellent biological fixation. More investigations of the outcomes of this EBM-produced porous trabecular titanium cup are needed in larger volume of patients and at longer term follow-up.”

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