Abstract: BACKGROUND: Schatzke type II fractures often involve the posterolateral plateau, resulting in weakened bone strength, increased fixation challenges, and increased risk of postoperative collapse. Optimizing treatment strategies to balance stability and minimize trauma is urgently needed.
OBJECTIVE: To evaluate the clinical efficacy of simple lateral L-shaped plate fixation for osteoporotic Schatzker type II tibial plateau fractures involving the posterolateral aspect, and to compare its biomechanical properties with those of lateral L-shaped plate combined with posterior T-shaped plate fixation using finite element analysis.
METHODS: A retrospective analysis was conducted on 39 patients with osteoporotic Schatzker type II tibial plateau fractures involving the posterolateral aspect treated between January 2018 and December 2023. Patients were divided into L-shaped plate group (simple lateral L-shaped plate fixation, n=24) and combined group (lateral L-shaped plate combined with posterior T-shaped plate fixation, n=15). Key indicators were compared, including operative time, intraoperative blood loss, bone mineral density, preoperative tibial plateau collapse, time from injury to surgery, postoperative radiographic parameters (tibial plateau varus angle and posterior tilt angle), knee range of motion, and Hospital for Special Surgery and Lysholm scores. Simultaneously, finite element models of Schatzker type II tibial plateau fracture were established based on CT data from a healthy adult male. Four groups were constructed: non-osteoporotic bone (Group A: simple L-shaped plate; Group B: L-shaped + T-shaped plate) and osteoporotic bone (Group C: simple L-shaped plate; Group D: L-shaped + T-shaped plate). Under axial loads of 250, 500, and 750 N, the overall displacement, tibial stress, and internal fixation stress of the models were analyzed in each group.
RESULTS AND CONCLUSION: (1) Clinical trial results: The results showed no significant differences between the two groups in age, gender, body mass index, bone mineral density, preoperative tibial plateau collapse, or time from injury to surgery (P > 0.05). Operative time and intraoperative blood loss in L-shaped plate group were significantly lower than those in combined group (P < 0.000 1). Immediate postoperative tibial plateau varus angle and posterior tilt angle showed no significant differences between groups (P > 0.05). At the final follow-up, the varus angle in L-shaped plate group was smaller than in combined group (P=0.04), while the posterior tilt angle showed no significant difference (P > 0.05). At the final follow-up, no statistical differences were observed in knee range of motion, Hospital for Special Surgery scores, or Lysholm scores between groups (P > 0.05). (2) Finite element analysis results: Under the same loads, both non-osteoporotic and osteoporotic bone models with T-shaped plate-assisted fixation (Groups B/D) exhibited superior performance in terms of overall displacement and lower tibial stress compared with simple L-shaped plate fixation (Groups A/C). (3) These findings suggest that for osteoporotic Schatzker type II tibial plateau fractures involving the posterolateral aspect, simple lateral L-shaped plate fixation can achieve satisfactory reduction stability and functional recovery, with clinical outcomes comparable to dual-plate fixation. Finite element analysis indicates superior biomechanical performance with dual-plate fixation; however, considering the significantly reduced surgical trauma and favorable clinical outcomes with simple lateral L-shaped plate fixation, routine addition of a posterior T-shaped plate is not necessary.

Key words: osteoporosis, Schatzker type II fracture, tibial plateau fracture, lateral L-shaped plate, finite element analysis