2025 ISAKOS Congress in Munich, Germany

2025 ISAKOS Biennial Congress Paper


Patellofemoral Osteoarthritis Did Not Affect Early Clinical Outcomes After Medial Opening Wedge High Tibial Osteotomy: A Match Paired Analysis

Giacomo Dal Fabbro, MD, Sydney, New South Wales AUSTRALIA
Margherita Bonaiuti, PhD, Bologna ITALY
Coral Castillejo Iniesta, MD, Marbella, Málaga SPAIN
Giovanni Balboni, MD, Ferrara ITALY
Fulvia Taddei, ENG, Bologna ITALY
Claudio Belvedere, PhD, Bologna, Bologna ITALY
Luca Macchiarola, MD, Foggia ITALY
Luca Ambrosini, MD, Bologna, Bologna ITALY
Alberto Grassi, PhD, Bologna ITALY
Stefano Zaffagnini, MD, Prof., Bologna ITALY

Istituto Ortopedico Rizzoli, Bologna, ITALY

FDA Status Cleared

Summary

The presence of preoperative patellofemoral osteoarthritis did not show negative impact on short term patient-reported outcomes in patients who underwent opening wedge high tibial osteotomy for medial osteoarthritis and varus knee.

Abstract

Background

Patellofemoral osteoarthritis (PFOA) has been considered a relative contraindication to valgus-producing high tibial osteotomy in patients affected by medial knee pain osteoarthritis (OA) and varus malalignment. However, clear evidence about the impact of preoperative PFOA on clinical outcomes after high tibial osteotomy is still lacking. The aim of the present study was to assess the effect of preoperative PFOA on the early patient-reported outcomes (PROMs) after medial opening wedge high tibial osteotomy (OWHTO).

Methods

Among a prospective cohort of isolated OWHTO procedures for treatment of medial OA (grade 2-3 according to Kellgren-Lawrence) and varus knee performed between 2020 and 2023, the patients with moderate to severe preoperative PFOA were selected and matched for gender, age and amount of hip-knee-ankle angle (HKA) correction with patients of the same cohort without PFOA. PFOA was assessed according to the Iwano classification system, evaluated on the preoperative axial view radiographs at 30° of knee flexion. Patients with a stage ≤1 were considered PFOA-free (group 1), while patients with stage 2 or 3 were considered to have preoperative PFOA (group 2). The Knee Injury and Osteoarthritis Outcome Score (KOOS) with its sub-scales and the Visual Analogue Scale for pain (VAS) were evaluated preoperatively and at one year follow up.
The statistical analysis was performed using R-studio (4.3.2, Posit PBC, Wien, Austria).
The Wilcoxon test was applied to evaluate the difference between the group 1 and the group 2 in preoperative and postoperative scores and in the magnitude of score changes between preoperative and follow up evaluation. Additionally, the differences between the group 1 and the group 2 were also assessed in terms of the number of patients with values below the patient acceptable symptom state (PASS) at follow-up, as well as the number of patients with change in PROMs below the minimal clinically important difference (MCID) using the Fisher's exact test. Statistical significance was set at p < 0.05.

Results

After matching the groups, 48 patients were included in the study: 24 patients in group 1, and 24 patients in group 2. No statistically significant differences were found for the matched comparison between group 1 and group 2 for all the preoperative scores (p>0.05). No statistically significant differences were found in the matched comparison between the two groups for all postoperative clinical outcomes except for VAS score, which was lower in group 2 (p<0.05). The analysis of changes in PROMs between preoperative and follow up period did not show significant differences between the two matched groups (p>0.05). The difference between the two groups in the number of patients with values below the PASS for VAS and KOOS sub scores did not show any significance except for KOOS pain, whose value was below the PASS for more patientin group 1 (p<0.05). Any significance between the two groups was found in the number of patients who experienced an improvement in PROMs lower than the MCID reported in the literature for all the assessed PROMs (p>0.05).

Conclusion

Moderate to severe preoperative PFOA did not affect the clinical outcomes at short term follow up. Early clinical outcomes similar or even better than those of patients without PFOA could be expected in patients with preoperative PFOA.