Intrinsic stresses on bone and cartilage in the normal and anterior cruciate ligament-reconstructed knee before and after a half marathon: a magnetic resonance imaging analysis

Abstract

Objective: To investigate intrinsic changes of the anterior cruciate ligament-reconstructed and control (contralateral) knees after a half marathon.

Design: Prospective case series.

Setting: Sports Medicine Clinic.

Participants: Eight runners were included in the analysis.

Interventions: Magnetic resonance imaging (MRI) of both knees within 48 hours before and after competition. Participants completed the Tegner Activity Level Scale and a Knee Demographic Questionnaire before the preevent MRI scan.

Main outcome measures: The incidence of MRI-identified cartilage, ligament, bone, and meniscus pathology in the ACL-reconstructed and control knees.

Results: The control knees of 5 runners (63%) demonstrated cartilage lesions, but no change was evident on postevent MRI. Preevent MRI in ACL-reconstructed knees demonstrated Grade IV meniscal lesions (4 of 8), Grades II (2 of 8) and IV cartilage lesions (4 of 8), and Type I bony edema (4 of 8). Although not significant, ACL-reconstructed knees demonstrated a strong trend (P = 0.01) toward a greater incidence of bone marrow edema on postevent MRIs compared with control knees.

Conclusions: This is the first study to compare the effects of running on intrinsic structures of a normal and ACL-reconstructed knee. Reconstructed knees demonstrated a greater incidence of bone marrow edema on postevent scans, but knee pathology evident on preevent scans did not progress in either control or ACL-reconstructed knees.