Relationship between Changes in Physical Activity and Knee Health 18 Months after ACL Reconstruction

Area of Science:

• Orthopedics
• Sports Medicine
• Rehabilitation Science

Background:

• Anterior cruciate ligament reconstruction (ACLR) is a common surgery for knee injuries.
• Understanding factors influencing long-term knee health post-ACLR is crucial for patient recovery and function.
• Physical activity (PA) is a key component of rehabilitation, but its relationship with knee health after ACLR requires further investigation.

Purpose of the Study:

• To investigate the association between changes in daily physical activity (PA) and knee health.
• To evaluate knee health using both structural (MRI-based cartilage assessment) and functional (patient-reported and objective measures) parameters.
• To determine these relationships at 18 months following ACLR.

Main Methods:

• Eighteen individuals (mean age 19.7 years) underwent assessments at 6 and 18 months post-ACLR.
• Daily steps were measured using accelerometers; knee cartilage health was assessed via MRI T2 relaxation times.
• Knee function was evaluated using the International Knee Documentation Committee Subjective Knee Form (IKDC) and isometric quadriceps strength.

Main Results:

• Average daily steps showed no significant change between 6 and 18 months post-ACLR (approximately 7500 steps/day).
• No statistically significant association was found between the change in daily PA and the change in cartilage T2 relaxation times (p=0.069).
• Physical activity changes were also not associated with patient-reported or objectively measured knee function at 18 months post-ACLR (p=0.638).

Conclusions:

• Daily step counts remained consistent from 6 to 18 months after ACLR in this cohort.
• Physical activity levels during this period were not linked to structural or functional knee health outcomes 18 months post-surgery.
• Further research may explore other factors influencing knee health after ACLR.