The relationship between Parson's tubercle and the insertion of the anterior horn of the medial meniscus

Purpose: The purpose of this investigation was to correlate the anatomic ch aracteristics of the third intercondylar tubercle of Parsons (TITP) with th e insertional variations of the anterior horn of the medial meniscus using precise measurements in an anatomic cadaver study. Our hypothesis was that the height of the TITP would correlate with the degree of inferior insertio n of the medial meniscus. Type of Study: A cadaver study using a convenienc e sample. Methods: Twenty unpaired proximal tibia specimens without advance d arthritis were analyzed with a coordinate measuring machine using a 0.479 -mm diameter probe. A reference plane was created using 3 reproducible poin ts on the tibial surface. Measurements from the TITP included another refer ence plane through its base, which was used to calculate its absolute heigh t. The locations of the anterior- and inferior-most insertional points of t he anterior horn of the medial meniscus were also determined. Correlations between the height of the TITP and age were also made. Results: The overall height of the TITP was found to correlate with the degree of inferior inse rtion of the anterior horn of the medial meniscus (r=.52, P=.019). No corre lation was found with the anterior placement of the meniscus (r=.12, P=.629 ) or with the age of the specimen (r=.14, P=.592). Conclusions: This absolu te height of the TITP correlates with the inferior location of the insertio n of the anterior hom of the medial meniscus. This association suggests a d evelopmental relationship between 2 anatomic structures within the knee.