Normal patellofemoral kinematic patterns during daily activities in dogs

Abstract

BackgroundPatellar abnormalities are a common cause of pain and lameness in dogs; however, in vivo the relative motion between the femur and patella in dogs is not well described. The objective of this study was to define normal in vivo sagittal plane patellofemoral kinematics in three axes of motion using non-invasive methods. We hypothesized patellofemoral alignment in the sagittal plane would tightly correlate with the femorotibial flexion angle. Six healthy dogs without orthopedic disease underwent computed tomography (CT) of their hind limbs to create 3-D models of the patella and femur. Normal stifle joint motion was captured via flat-panel imaging while each dog performed a series of routine activities, including sitting, walking, and trotting. The 3-D models of the patella and femur were digitally superimposed over the radiographic images with shape-matching software and the precise movement of the patella relative to the femur was calculated.ResultsAs the femorotibial joint flexed, the patellofemoral joint also flexed and the patella moved caudally and distally within the femoral trochlea during each activity. Patellar flexion and distal translation during walk and sit were linearly coupled with the femorotibial flexion angle. Offset was evident while trotting, where patella poses were significantly different between early and late swing phase (p ≤ 0.003). Patellar flexion ranged from 51 to 6° while trotting. The largest flexion angle (92°) occurred during sit. The patella traversed the entire proximodistal length of the femoral trochlea during these daily activities.ConclusionsUsing single-plane flat-panel imaging, we demonstrated normal in vivo patellofemoral kinematics is tightly coupled with femorotibial kinematics; however, trot kinematic patterns did not follow the path defined by walking and stand-to-sit motions. Our normal data can be used in future studies to help define patellofemoral joint kinematics in dogs with stifle abnormalities.

Arthroscopic Articular Cartilage Scores of the Canine Stifle Joint with Naturally Occurring Cranial Cruciate Ligament Disease

“…12,25 Conversely, in an in vivo evaluation of PF joint kinematics using single, sagittal plane fluoroscopy in dogs with cranial cruciate ligament deficient stifles, the entire patella was displaced distally throughout the gait cycle. 28,29 This distal displacement of the patella was attributed to the increased femorotibial flexion angle noted in dogs with cranial cruciate ligament deficient stifles at a walk and suggested that the proximal trochlear groove cartilage lesions may be induced by inadequate PF contact 28 rather than a proximal shift in contact area. 12,25 Despite the unknown reason for induction of cartilage damage at the proximal trochlear groove location, it is known that abnormal joint loading and alignment are risk factors for the development of osteoarthritis.…”

Patellofemoral kinematics in dogs with cranial cruciate ligament insufficiency: an in-vivo fluoroscopic analysis during walking

“…Three-dimensional digital bone models of the affected and contralateral femurs and patellas were created; the cortical bone margins were segmented using an open source 3D segmentation software program 3 , and these point-clouds were converted into polygonal surface models with a reverse engineering software program 4 . Anatomic coordinate systems were applied to the bone models based on anatomical landmarks of the patella and femur [ 23 ]. Femoral coordinates were applied such that the mediolateral axis (z-axis) passed through the center of the lateral and medial femoral condyles with the femoral origin located at the mid-point between the condyles (Fig.…”

“…The digital bone models of the patella and femur were superimposed over the fluoroscopic images and their projected silhouettes were translated and rotated such that the contours precisely matched the corresponding contours of the fluoroscopic images 5 , as previously described (Fig. 2 ) [ 23 ]. The patella was positioned centrally within the trochlear groove, such that the articulating surface of the patella at the center of the patella remained as congruent as possible with the trochlear groove in the axial plane.…”

“…Dynamic in-vivo joint kinematics can be accurately quantified in a non-invasive manner with fluoroscopic techniques [ 18 – 22 ]. Using single plane fluoroscopy, our group has previously determined sagittal-plane PF kinematics in normal dogs during various daily activities [ 23 ]. We corroborated that PF kinematics are tightly coupled to femorotibial kinematics, but vary according to the type of activity performed [ 23 ].…”

“…Using single plane fluoroscopy, our group has previously determined sagittal-plane PF kinematics in normal dogs during various daily activities [ 23 ]. We corroborated that PF kinematics are tightly coupled to femorotibial kinematics, but vary according to the type of activity performed [ 23 ]. To the authors’ knowledge, there are no in-vivo quantitative studies on PF kinematics in dogs with CrCL rupture.…”