2023 ISAKOS Biennial Congress ePoster
Derotational Distal Femoral Osteotomy for Patients with Recurrent Patellar Instability and Increased Femoral Antetorsion Improves Knee Function and Adequately Treats Both Torsional and Valgus Malalignment
Maximilian Hinz, MD, Munich GERMANY
Matthias Cotic, MSc, Munich, Bavaria GERMANY
Theresa Diermeier, MD, Berlin GERMANY
Florian B. Imhoff, MD, Priv.-Doz., Zurich SWITZERLAND
Georg C. Feuerriegel, MD, Munich, Bavaria GERMANY
Klaus Wörtler, MD, Prof., Munich, Bavaria GERMANY
Alexander Themessl, MD, Munich GERMANY
Andreas B. Imhoff, MD, Prof. Emeritus, Sauerlach / Munich, Bavaria GERMANY
Andrea E. Achtnich, Assoc. Prof., Munich GERMANY
Department of Sports Orthopaedics, Technical University of Munich, Munich, Bavaria, GERMANY
FDA Status Cleared
Summary
Derotational distal femoral osteotomy achieves a significant reduction in pain, an improvement of subjective knee funtion, as well as an adequate correction of torsional and coronal limb alignment in patients with patellofemoral instability and an associated increased femoral antetorsion.
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Abstract
Purpose
The aim of the study was to evaluate the functional and radiological outcome following derotational distal femoral osteotomy (D-DFO) in patients with high-grade patellofemoral instability (PFI) and an associated increased femoral antetorsion (FA). It was hypothesized that D-DFO would lead to a good functional and radiological outcome, and that both torsional and coronal malalignment could be normalized.
Methods
Patients that underwent D-DFO between 06/2011 and 12/2018 for high-grade PFI with an increased FA (>20°) were included. Patient-reported outcome measures (Visual Analog Scale [VAS] for pain, Kujala score, Lysholm score, International Knee Documentation Committee subjective knee form [IKDC], Tegner Activity Scale [TAS]) were evaluated pre- and minimum 24 months postoperatively. Magnetic resonance imaging of the lower extremity and weight-bearing whole-leg anteroposterior radiographs were conducted pre- and postoperatively. The change in FA, coronal limb alignment and PROMs were tested for statistical significance.
Results
In total, 27 patients (30 knees), were included. The D-DFO aimed to only correct FA (Group 1) or to additionally perform a varization (Group 2) in 14 cases each. In the remaining two cases, double-level osteotomies were performed to correct additional tibial deformities. In 25 cases (83.3%), concomitant procedures also addressing patellofemoral instability were performed. At follow-up (38.0 months [25-75% interquartile range 31.8-52.5 months]), a significant reduction in pain (VAS for pain: 2.0 [1.0-5.0] vs. 0 [0-1.0], p < 0.05), significant improvement in knee function (Kujala score: 55.6 ± 13.6 vs. 80.3 ± 16.7, p < 0.05; Lysholm score: 58.6 ± SD 17.4 vs. 79.5 ± 16.6, p < 0.05; IKDC: 54.6 ± 18.7 vs. 74.1 ± 15.0, p < 0.05), and an increase in sporting activity (TAS: 3.0 [3.0-4.0] vs. 4.0 [3.0-5.0], p = n.s.) were reported. Femoral antetorsion was significantly reduced (28.2 ± 6.4° vs. 13.6 ± 5.2°, p < 0.05). A significant varization was observed in Group 2 (2.4 ± 1.2° valgus vs. 0.3 ± 2.4° valgus; p < 0.05). In one case, patellar redislocation occurred 70 months postoperatively.
Conclusion
In patients with PFI and an associated increased FA, D-DFO achieved a significant reduction in pain, an improvement of subjective knee function, as well as an adequate correction of torsional and coronal alignment.