The impact of proximal fibula resection on foot and ankle biomechanics: A radiological and pedobarographic evaluation

Objectives: This study aims to evaluate whether changes in ankle radiological parameters following fibular head resection due to tumors lead to ankle instability and/or ankle arthritis and to assess the impact of resection on clinical outcomes using pedobarographic analysis and pain and function scales. Patients and methods: Between January 2005 and January 2023, a total of 30 patients (10 males, 20 females; mean age: 33.9 +/- 13.8 years; range, 10 to 67 years) who underwent proximal fibula resection were retrospectively analyzed. We assessed fibular rotation using axial ankle magnetic resonance imaging (MRI), fibular length, talar tilt angle, and talotibial angle changes using X-ray, foot load distribution changes through pedobarographic measurements, and clinical outcomes using the Visual Analog Scale (VAS) and Musculoskeletal Tumor Society (MSTS) scores. Results: Fibular length and rotation were significantly reduced, while talar tilt and talocrural angle were higher on the operated side. Additionally, load balance and maximum pressure in the second to fifth toes (T2-5 regions) were significantly lower on the operated side. The mean VAS score was 1.5 +/- 1.4 and the mean MSTS score was 26.8 +/- 2.9. The MSTS scores showed weak negative correlations with differences in fibular length, fibular rotation, talar tilt, and talocrural angle, none of which were statistically significant (r=-0.35, -0.3, -0.1, -0.1, p=0.06, 0.1, 0.62, 0.61). In contrast, the VAS score showed a significant positive correlation with fibular length difference (r=0.45, p=0.01), while correlations with other parameters were not significant. A positive correlation was observed between the percentage of resected fibula and differences in fibular rotation (r=0.67, p<0.001), fibular length (r=0.73, p<0.001), talocrural angle (r=0.49, p=0.003), and talar tilt angle (r=0.66, p<0.001); this correlation was more pronounced in patients with more than 30% resection. Conclusion: Proximal fibula resection for tumors involving the fibular head leads to significant changes in ankle radiological measurements and load distribution. Despite these changes, clinical outcomes, as reflected by low VAS scores and high MSTS scores, indicate generally favorable patient-reported outcomes.