Trabecular bone strain changes associated with cartilage defects in the proximal and distal tibia

Area of Science:

• Orthopedic Surgery
• Biomechanics
• Bone Research

Background:

• Intraarticular fractures involving cartilage defects are a significant risk factor for developing post-traumatic arthritis (PTA).
• The biomechanical consequences of cartilage damage on subchondral bone load transmission remain incompletely understood.
• Distinct clinical outcomes are observed for proximal versus distal tibial intraarticular fractures.

Purpose of the Study:

• To investigate the impact of cartilage defects on load transmission through subchondral trabecular bone in human cadaveric knees and ankles.
• To elucidate the pathomechanics underlying post-traumatic arthritis development following tibial fractures.
• To correlate changes in bone strain with defect size and location in the tibia.

Main Methods:

• Creation of full-thickness cartilage defects in meniscectomized human cadaveric proximal and distal tibiae.
• Measurement of trabecular bone strain using the Texture Correlation technique.
• Comparison of digital radiographs of unloaded and loaded bone samples to quantify strain distribution.

Main Results:

• Cartilage defects led to decreased trabecular bone strain in the proximal tibia and increased strain in the distal tibia.
• The subchondral bone column directly beneath the defect on the tibial plateau exhibited the most significant strain reduction.
• The distal tibia showed the most substantial strain increases near the joint line and in the anterior third, with smaller defects causing greater strain changes.

Conclusions:

• Disturbances in subchondral bone load transmission due to cartilage defects are implicated in post-traumatic arthritis.
• Altered strain patterns in the tibia following intraarticular fractures may be critical mechanical factors in PTA pathogenesis.
• The differential effects on strain in the proximal and distal tibia may explain the varied clinical trajectories of tibial fractures.