Comparison of the clinical and radiological outcomes of Puddu and TomoFix plates for medial opening-wedge high tibial osteotomy: A two-year follow-up of a randomized controlled trial.

ABSTRACT

PURPOSE: Opening-wedge high tibial osteotomy (OWHTO) requires fixation devices for stabilization of the osteotomy gap. The two most commonly used fixation devices are the Puddu and the TomoFix plates. Based on its design, each implant generates a characteristic stability profile. The aim of this randomized controlled trial (RCT) was to investigate the short-term clinical and radiological outcomes of OWHTO using the Puddu and TomoFix plating systems. We hypothesized that the TomoFix plate would achieve superior clinical and radiographic results compared to the Puddu plate. METHODS: A total of 60 patients were randomly allocated to undergo OWHTO either using the Puddu plate or the TomoFix plate if conservative treatment failed with symptomatic medial compartment knee osteoarthritis (OA) stage I or II according to Ahlbäck classification, and varus malalignment. All patients underwent clinical and radiological assessment preoperatively, and at 3, 6, 12, and 24months postoperatively. Radiological measurement of the hip-knee-ankle (HKA) angle, and posterior tibial slope (PTS) was performed. Functional assessment was carried out using the Hospital for Special Surgery Knee-Rating Scale (HSS) and the Western Ontario McMaster Universities (WOMAC) Osteoarthritis Index. Patients were also evaluated for intraoperative and postoperative complications throughout the follow-up period. RESULTS: The mean angular correction was 9.6±4°, and 10.5±4.8° in the Puddu and TomoFix groups, respectively (p=0.488). The mean PTS change was significantly higher in the Puddu group (3.4±1.1°) compared to the TomoFix group (0.8±0.7°) (p<0.001). There was a statistically significant improvement in the mean HSS and WOMAC in both groups until one year postoperatively. Neither HSS nor WOMAC showed a statistically significant difference between the Puddu and TomoFix groups at any time during the first two postoperative years. The overall complication rate was not significantly different between the Puddu and TomoFix groups. However, the TomoFix group demonstrated higher incidence of symptomatic hardware (23% vs. 3.3%) and removal of metalwork (17% vs. 0%) than the Puddu group (p=0.023 and 0.020, respectively). CONCLUSION: This RCT suggests that the implant choice for OWHTO has no significant impact on functional outcomes during the first 2years postoperatively. While the Puddu plate was associated with an unintentional increase in the PTS during the surgery, both implants allowed coronal and sagittal plane corrections to be preserved postoperatively. The overall complication rates were similar, but the TomoFix required more material to be removed because it is more cumbersome. However, these results need to be confirmed on a larger scale. LEVEL OF EVIDENCE II; randomized controlled trial.