Evaluation of the Gross Anatomical Incidence of Fabellae in a North American Cadaveric Population
Location
Philadelphia, PA
Start Date
9-5-2018 1:00 PM
Description
Introduction: The fabella is a sesamoid bone found in the tendinous portion of the lateral head of the gastrocnemius muscle. It is present in 10-30% of humans, with an incidence as high as 87% in certain Asian populations (Driessen et al., 2014). No such evaluation of incidence has been conducted in a North American cadaveric population.
Objectives: The primary objective of this study was to examine the incidence, phenotype and composition of fabellae in a sample population of American cadavers from Pennsylvania.
Methods: Bilateral dissections were performed on the lateral and medial heads of the gastrocnemius muscles on 182 knees from 91 cadavers. The tendinous portion of the gastrocnemius muscle and fibrous capsule surrounding the lateral and medial condyles of the femur were reflected to expose the bone. Presence of both a bony or cartilaginous fabella, and of an impression on the posterior aspect of the femoral condyles were noted. Fabella composition was initially determined by inspection and palpation in the gastrocnemius muscle containing it as adapted from Kato et al. (2012). Femoral impressions were classified as medial or lateral in reference to their location to the condylar ridge of the lateral femoral condyle.
Results: Thirty cadavers had at least one fabella for a total cadaveric incidence of 32.9%. Twenty-two cadavers (24.2%) displayed bilateral presence, while 8 cadavers (8.8%) displayed a unilateral presence. Twenty-three cadavers (25.3%) displayed a bony fabella, while 7 cadavers (7.7%) displayed a cartilaginous fabella. Twenty-one cadavers (23%) displayed a medial phenotype while 8 (8.8%) displayed a lateral phenotype.
Conclusions: The general incidence of fabellae in this sample population was found to be slightly higher than the worldwide average of 30%. Further histological analysis needs to be conducted to analyze the cellular composition of the cartilaginous faballae found. The incidence of fabellae in the sample population may have implications in orthopedics and sports medicine, but there is a lack of data for clinical routine. Postero-lateral pathology such as fabella-associated ligament tears may be masked by extensive symptoms from cruciate ligament injury. Untreated damage in the postero-lateral compartment of the knee may prolong the healing process of cruciate ligament repair if the fabella and its associated structures are not noted during knee examination.
Embargo Period
5-30-2018
Evaluation of the Gross Anatomical Incidence of Fabellae in a North American Cadaveric Population
Philadelphia, PA
Introduction: The fabella is a sesamoid bone found in the tendinous portion of the lateral head of the gastrocnemius muscle. It is present in 10-30% of humans, with an incidence as high as 87% in certain Asian populations (Driessen et al., 2014). No such evaluation of incidence has been conducted in a North American cadaveric population.
Objectives: The primary objective of this study was to examine the incidence, phenotype and composition of fabellae in a sample population of American cadavers from Pennsylvania.
Methods: Bilateral dissections were performed on the lateral and medial heads of the gastrocnemius muscles on 182 knees from 91 cadavers. The tendinous portion of the gastrocnemius muscle and fibrous capsule surrounding the lateral and medial condyles of the femur were reflected to expose the bone. Presence of both a bony or cartilaginous fabella, and of an impression on the posterior aspect of the femoral condyles were noted. Fabella composition was initially determined by inspection and palpation in the gastrocnemius muscle containing it as adapted from Kato et al. (2012). Femoral impressions were classified as medial or lateral in reference to their location to the condylar ridge of the lateral femoral condyle.
Results: Thirty cadavers had at least one fabella for a total cadaveric incidence of 32.9%. Twenty-two cadavers (24.2%) displayed bilateral presence, while 8 cadavers (8.8%) displayed a unilateral presence. Twenty-three cadavers (25.3%) displayed a bony fabella, while 7 cadavers (7.7%) displayed a cartilaginous fabella. Twenty-one cadavers (23%) displayed a medial phenotype while 8 (8.8%) displayed a lateral phenotype.
Conclusions: The general incidence of fabellae in this sample population was found to be slightly higher than the worldwide average of 30%. Further histological analysis needs to be conducted to analyze the cellular composition of the cartilaginous faballae found. The incidence of fabellae in the sample population may have implications in orthopedics and sports medicine, but there is a lack of data for clinical routine. Postero-lateral pathology such as fabella-associated ligament tears may be masked by extensive symptoms from cruciate ligament injury. Untreated damage in the postero-lateral compartment of the knee may prolong the healing process of cruciate ligament repair if the fabella and its associated structures are not noted during knee examination.