Surgical exposure to posterolateral quadrant tibial plateau fractures: an anatomic comparison of posterolateral and posteromedial approaches

BACKGROUND: Management of posterolateral tibial plateau quadrant fractures can be challenging, and two posterior approaches were frequently used for exposure, reduction, and fixation: posterolateral approach and posteromedial approach. The purpose of this study was to compare their deep anatomical structure and analyze their limits and the risk of injury to important structures during surgical dissection of two approaches. METHOD: Five lower limb specimens were used in this study. After dissection of the skin and superficial fascia of each specimen, deep structures were dissected via posteromedial and posterolateral approach, and several parameters including perpendicular distance from the anterior tibial artery coursing through the interosseous membrane fissure to the lateral joint line and apex of fibular head and so on were measured and analyzed. RESULT: The perpendicular distance from the ATA coursing through the interosseous membrane fissure to the lateral joint line was 49.3 ± 5.6 mm (range 41.3–56.7 mm), while the distance to the apex of fibular head was 37.7 ± 7.2 mm (range 29.0–48.0 mm). The transverse distance of the anterior tibial vascular bundle is around 10 mm. The perpendicular distance from the top accompanying vein of the ATA bundle to lateral joint line and apex of fibular head was 44.1 ± 6.3 mm and 32.5 ± 7.6 mm, respectively. The maximum proportion of posterolateral tibial plateau shielded by the fibular head from the posterior view was 61.7 ± 4.9% (range 55.6–64.1%). The average length of popliteus muscle outside the joint was 83.1 ± 6.0 mm (range 76.5–92.2 mm), and the width in the middle was 28.1 ± 4.3 mm (range 26.6–29.1 mm). CONCLUSION: Although posterolateral approach seems more direct for exposure of posterolateral quadrant tibial plateau fracture, it has three major disadvantages in deep dissection. Posteromedial approach through the medial board of medial head of gastrocnemius–soleus may be safer, but it was hard for direct visualization of articular surface which limits it usage for only a few cases.