Comparison of the exposure on Distal Tibial Articular Surface for Posterior Pilon Fractures Via the Medial or Lateral Malleolar Osteotomy: A Preliminary Cadaveric Study

Fan Yang^1*Cheng Chen¹Moran Huang¹Yihao Sun¹Zhijun Shen¹Jian Hu²Lei Wang^1*

• ¹Shanghai Sixth People's Hospital, Shanghai Jiao Tong University, Shanghai, China
• ²Shanghai Municipal No 8 People's Hospital, Shanghai, China

Objective: To preliminarily investigate the exposure area of the distal tibial articular surface via the medial malleolar osteotomy or the transfibular osteotomy and provide quantitative reference for surgical approach selection. Methods: Five pairs of adult fresh frozen lower extremities were included in the study, and the left limb or right limb in each pair was divided randomly into medial approach group or posterolateral approach group. According to the computed tomography (CT) scan, the 3D printed guiding-plate was applied to assist the osteotomy on each specimens. The exposure area of the distal tibial articular surface was calculated after osteotomy. Results: Using the medial or posterolateral approach, the average ratio of the exposed distal tibial joint dome area to the total distal tibial joint dome area was 45.94 ± 12.79 % or 47.12 ± 12.84 %, respectively (S1). Corresponding intra-operative electrocautery marking (S2) yielded 62.72 ± 18.67 % and 53.26 ± 10.51 %. When the articular surface was subdivided into anterior, middle and posterior thirds, the posterior third demonstrated the greatest exposure (medial 61.3 ± 2.2 %; lateral 65.2 ± 1.8 %). Inter-observer ICC for S1 and S2 exceeded 0.89 (95 % CI 0.81–0.97). After maximal soft-tissue distraction, the exposed area further increased by 11.5 ± 2.1 % (medial) and 9.1 ± 1.6 % (lateral) without significant between-group difference (P = 0.08, paired t-test). Conclusion: Medial and lateral approaches could significantly expose the distal articular surface of the posteriortibia to a large extent after medial and lateral malleolus osteotomies. According to the position of the main fracture fragments on the posterior articular surface and proportion of their transverse distance as to the posterior pilon variant fracture, a suitable surgical approach conducive to adequate exposure and operation can be considered for individualized surgical planning. These preliminary data require clinical validation. In addition, intra-operative soft-tissue stretch enlarges the visual field by approximately 10 % regardless of approach, while high measurement reliability supports the clinical translation of these anatomical data.