Comparison of Anatomical Conformity between TomoFix Anatomical Plate and TomoFix Conventional Plate in Open-Wedge High Tibial Osteotomy

Are TomoFix Locking Plates Really Anatomical for Indian Population?

Purpose

The use of a TomoFix plate can be a challenge in Asian population who inherently have smaller tibial bones. This study aims to find out the normal proximal tibial morphometric measurements in Indian population and to compare the Medial Anterior Radius of Curvature (MAROC) of proximal tibia with the Proximal Part Radius of Curvature (PPROC) of the available TomoFix plates, to estimate conformity of the fit between them.

Methods

Retrospective Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) based proximal tibial measurements were performed on 824 knees, 664 females and 160 males (604 patients). The mean MAROC, mean MAROC in males and mean MAROC in females were compared to the PPROC of TomoFix plates.

Results

The radiological measurements revealed a mean AP length of 45.22 ± 3.79 mm, mean ML width of 69.04 ± 5.01 mm and mean MAROC of 21.88 ± 2.11 mm. The mean MAROC in males was 24.07 ± 2.1 mm, whereas in females it was 21.35 ± 1.75 mm. The mean MAROC, mean MAROC in males and mean MAROC in females when compared to the PPROC of Standard TomoFix plate (38 mm), Small TomoFix and Anatomical TomoFix plates (30 mm) showed a significant difference (p < 0.01), indicating that the radius of curvature of the plate does not match the radius of curvature of the anteromedial tibial plateau.

Conclusion

The TomoFix plates, including Small (Asian Version) and Anatomical plates, are relatively large for the Indian population. Our study may help the implant to designers develop a plate that will better suit the Indian population, improving results and reducing hardware-related complications of MOWHTO.

Risk Factors and Clinical Outcomes of Osteotomy Plane Violation by D-Hole Screws in Medial Open Wedge High Tibial Osteotomy: A Simulation and Comparative Study

Background and Objectives: Stable fixation is essential for successful healing after medial open wedge high tibial osteotomy (MOWHTO) to minimize the risk of non-union and correction loss. In Asians, potential complications such as D-hole screw osteotomy plane violation (D-hole violation) and inadequate plate fitting arise due to improper plate size. This study aimed to evaluate the risk factors for D-hole violation and compare the conventional anatomic (CA) plate with an individualized anatomic (IA) plate in MOWHTO procedures. Materials and Methods: A simulation study on D-hole violation using the CA plate was conducted, involving preoperative radiographs and CT scans of 64 lower extremities from 47 MOWHTO patients. Additionally, a randomized controlled study compared CA and IA plates in MOWHTO procedures with 34 patients (17 in the CA plate group; 18 in the IA plate group). Patient demographics, patient-reported outcome measures (PROMs), and radiological measures were analyzed. Results: In the simulation study, the rates of D-hole violation ranged from 20.3% to 59.4%, with an increase observed as the plate was distalized from 5 mm to 10 mm away from the joint line. Short stature was identified as an independent risk factor for D-hole violation (p < 0.001), with a cutoff value of 155.3 cm. In the randomized controlled study, no significant difference in PROMs and D-hole violation was observed between the CA plate and IA plate groups. However, the IA plate group showed better plate fitting compared to the CA plate group (p = 0.041). Conclusions: This study identified a high risk of D-hole screw osteotomy plane violations in MOWHTO procedures, particularly when the plate is positioned more distally and in individuals with a stature below 155.3 cm. It also revealed that individualized plates provide better tibial fitting compared to conventional anatomic plates, particularly in Asian populations where tibial morphology tends to be shorter than in Western populations. Therefore, evaluating patient stature and selecting tailored plates are essential to optimize plate positioning and minimize plate-related complications in MOWHTO procedures.