Using novel porous metal pillars for tibial bone defects in primary total knee arthroplasty

Abstract

Background: The optimal method to treat tibial bone defects during primary total knee arthroplasty (TKA) is still unclear. A novel technique of porous metal pillar augmentation has been applied recently. This study aimed to assess the short-term outcomes of primary TKA with the use of novel porous metal pillars for tibial bone defects.

Methods: A total of 24 cases (22 patients) of primary TKA between January 2019 and December 2020 using porous metal pillars for tibial bone defects were reviewed. Clinical results were evaluated using the Knee Society knee score (KSKS) and function score (KSFS), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and range of motion (ROM). Hip-knee-ankle angle (HKAA), femorotibial angle (FTA), and radiolucent lines were assessed radiologically.

Results: The median follow-up period was 36.0 months (interquartile range: 31-37 months). The KSKS, KSFS, WOMAC score, and ROM improved significantly at the final follow-up assessment compared with the preoperative evaluation. Both of the HKAA and FTA were corrected after surgery. Only one knee had a nonprogressive radiolucent line at the bone-cement interface. No radiolucent lines were detected around the pillar in any of the cases. There were no cases of prosthesis loosening and revision.

Conclusions: The use of novel porous metal pillars yielded satisfactory clinical outcomes and reliable radiological evidence of fixation in this study with a minimum 2-year follow-up. Porous metal pillar augmentation can be considered as a valuable and easy-to-use method for the management of tibial bone defects in primary TKA.

Keywords: Augmentation; Bone defect; Porous metal pillar; Total knee arthroplasty.

Fig. 1

Porous metal pillar and instrumentation. A Porous metal pillars with different height. B Instrumentation comprised of drill, drill guide, trial, and impactor

Fig. 2

Porous metal pillar augmentation technique for uncontained tibial bone defect. A Bone defect was debrided. B Holes were drilled in the area of the bone defect. C The pillars were impacted into place with the top of the pillar just below the tibial cutting surface. D Bone cement was placed on the surface of the tibial resection, around the pillar, and in the area of the bone defect

Fig. 3

Preoperative and postoperative radiographs of a 64-year-old female patient. A Osteoarthritis was evidenced on the preoperative anteroposterior radiograph. B Osteoarthritis was evidenced on the preoperative lateral radiograph. C Trabecular bone formation (yellow arrow) around the pillar was noted on the anteroposterior radiograph 2.5 years after surgery. D Trabecular bone formation (yellow arrow) around the pillar was noted on the lateral radiograph 2.5 years after surgery