Lesion Size Location Dependency on Maximum Pressure in Osteochondral Defects: Experiments and Finite-Element Analysis

Area of Science:

• Biomechanics
• Orthopedics
• Sports Medicine

Background:

• Osteochondral defects (OCDs) in the knee joint significantly impact contact pressures and their distribution.
• Understanding the influence of defect size and location is vital for developing effective therapeutic strategies.

Purpose of the Study:

• To investigate how osteochondral defect size and location affect knee joint contact pressures and pressure distribution.
• To hypothesize that larger defects elevate contact pressures and alter distribution, varying by location.

Main Methods:

• Utilized 6 cadaveric knees for mechanical testing of contact pressures under compressive loading.
• Employed computed tomography (CT) and finite-element analysis (FEA) to model varying defect sizes and locations.
• Analyzed associations between contact pressure, defect size, and location using ANOVA and Fisher exact tests.

Main Results:

• Increased defect size correlated with higher contact pressures on medial and lateral femoral condyles at full extension (P=.013, P=.024).
• No significant pressure differences were observed at 30° flexion (P=.674, P=.333).
• FEA indicated increased pressure and stress with 7mm defects; peak pressures shifted laterally with larger defects.

Conclusions:

• Defect size, location, and alignment significantly impact knee joint contact pressures.
• Intervention is crucial for defects exceeding 3mm, as significant stress increases occur beyond this threshold.
• Findings highlight the biomechanical implications of osteochondral defects, informing clinical practice and sports medicine.