Alterations in patellofemoral kinematics following vastus medialis transection in the anterior cruciate ligament deficient rabbit knee

Vastus lateralis and vastus medialis produce distinct mediolateral forces on the patella but similar forces on the tibia in the rat

“…A similar angular separation between VM and VL lines of action was observed in humans in vivo (Wilson and Sheehan, 2010). These observations are consistent with suggestions that the direction of muscle action is primarily determined by the geometry of internal tendons within muscles rather than by local muscle fiber orientations near the patella (Egloff et al, 2014; Sawatsky et al, 2012). As a consequence, the difference in VM and VL actions might be considerably smaller than estimated previously.…”

“…Opposing patellar actions of VM and VL have been suggested from a range of experiments using in vivo measurements in humans (Lin et al, 2010; Sheehan et al, 2012; Wilson and Sheehan, 2009, 2010), cadaveric measurements (Ahmed et al, 1983; Elias et al, 2009; Goh et al, 1995; Lee et al, 2002; Lorenz et al, 2012; Sakai et al, 2000), and computational simulations (Dhaher and Kahn, 2002; Elias et al, 2010). However, other studies in rabbits have shown that removing VM has minimal effects on either patellofemoral contact forces (Sawatsky et al, 2012) or on patellar kinematics (Egloff et al, 2014). These latter studies suggested that the difference in mediolateral forces produced by VM and VL might be smaller than generally thought.…”

“…Most studies have instead measured VM and VL actions indirectly and, as a consequence, these measurements might not reflect the true action of these muscles. For example, cadaveric experiments usually estimate muscle directions from measurement of muscle fiber orientation near the patella, whereas the actual muscle direction might be determined by the geometry of the internal tendon and attachment points of a muscle (Egloff et al, 2014; Sawatsky et al, 2012). Cadaveric studies might therefore exaggerate the difference between the actions of VM and VL on the patella.…”

“…Cadaveric studies might therefore exaggerate the difference between the actions of VM and VL on the patella. Similarly, in vivo experiments measuring patellar kinematics after stimulating or paralyzing VM or VL provide an indirect characterization of muscle actions on the patella (Egloff et al, 2014; Lin et al, 2010; Sawatsky et al, 2012; Sheehan et al, 2012), since patellar kinematics are influenced by the compliance of soft tissues around the patella and patellofemoral contact interactions (Amis, 2007; Farahmand et al, 1998; Powers, 2000b; Powers et al, 2017). Wilson and Sheehan (Wilson and Sheehan, 2010) estimated the lines of action of VM and VL in vivo from measurement of muscle attachments using MRI and found that VM and VL had opposing mediolateral directions.…”

Impact of Simulated Knee Injuries on the Patellofemoral and Tibiofemoral Kinematics Investigated with an Electromagnetic Tracking Approach: A Cadaver Study

“…The transecting of the ligaments and MM was performed by an experienced orthopaedic surgeon. ACL rupture is a common sports injury that can lead to possible degenerative joint changes [ 35 , 36 ]. Additionally, we chose to simulate a meniscal tear because it is the most common knee injury, and partial meniscectomies are the most common orthopaedic surgical procedure [ 37 ].…”