# Biointegrative Fixation for Tibial Tubercle Osteotomy Is Effective and May Lower Removal Rate

## TL;DR

Biointegrative screws used in tibial tubercle osteotomy show similar safety and effectiveness as metal screws but may reduce the need for hardware removal.

## Contribution

Introduces biointegrative fiber-reinforced implants as a novel alternative to metal screws for tibial tubercle osteotomy.

## Key findings

- Biointegrative screws achieved clinical union by 6 months with no differences in time to union compared to metal screws.
- Biointegrative fixation had a 0% hardware removal rate versus 29.5% for metal screws.
- Biointegrative screws showed no increased risk of infection compared to metal screws.

## Abstract

To report the safety and efficacy of biointegrative fiber-reinforced implants for tibial tubercle osteotomy (TTO) and perform a cost-benefit analysis.

Patients treated with TTO for all indications by a single surgeon from May 2017 to July 2024 were retrospectively reviewed. There were no exclusion criteria. In 2023, the surgeon switched TTO fixation from two 4.5-mm metal compression screws to 2 biointegrative, partially threaded 4.0-mm headless compression screws, made of continuous mineral fibers comprised of elements found in natural bone (SiO2, Na2O, CaO, MgO, B2O3, and P2O5), and bound together by PLDLA [poly (L-lactide-co-D,L-lactide)] (70:30 L:DL) in 50% weight by weight ratio. Postoperative protocols were consistent across fixation types, with full weight-bearing as tolerated in full extension for 6 weeks and range of motion from 0 to 90° allowed immediately. Patients were followed longitudinally for osseous union, recurrent instability, and return to the operating room.

Sixty-two TTOs were analyzed (44 metal, 18 biointegrative); 61.3% of patients were female, and the median age was 23.3 years (interquartile range 22.5). One patient with biointegrative implants underwent irrigation and debridement with implant retention at 9 days postoperatively. Mean follow-up for biointegrative fixation was 1.3 ± 0.4 years (range: 0.5-1.8) and for metal fixation was 3.5 ± 1.8 years (range: 0.4-6.7), P < .001. All patients achieved clinical union by 6 months without differences in time to clinical union (P = .159). Hardware removal rates differed between metal versus biointegrative groups (29.5 vs 0%, P = .009) but otherwise did not differ for rates of superficial infection (2.3 vs 0%, P = .519) or deep infection (2.3 vs 5.6%, P = .507).

Biointegrative screws are a safe and effective alternative to metal screws for TTO in short-term follow-up. The use of biointegrative fixation may reduce the need for secondary hardware removal procedures commonly reported with 4.5-mm metal screws, albeit at a potentially increased cost to the health system.

Level III, retrospective comparative study.