Ruofu et al. [ 27] determined the optimal entry point by using the CT reconstruction and found large individual variation in vertical and horizontal offset in reference to the inferior edge of superior articular facet and lateral edge of the lateral mass.
It has a smooth ridge that divides its articular surface into two facets: a triangular lateral facet, which connects with the scaphoid (a wrist bone), and a quadrilateral medial facet, which connects with the lunate (another wrist bone).
Osteochondral fracture fragments can shear from the medial patellar facet or lateral femoral condyle after patellar dislocation/subluxation (Fig. 10) [1].
The Sanders CT-scan classification is based on the articular fracture lines of the posterior articular calcaneal facet (A, lateral; B, central; C, medial), and the severity of the fracture (Sanders types I IV) depends on the number of lines and their courses.
Spinal canal, facet joint, lateral recess, and foraminal morphology were assessed using computed tomography.
In later stages, the lateral facet remodels into a concave shape and starts to ride over the lateral femoral condyle.
As it is known from the STM data [39], р-cluster has regular-shaped faceting of the pyramid, where the lateral facet of the pyramid is a plane (105) inclined at an angle α of 10.9° to the base plane (001).
The period of the nanopillars is 300 nm (corresponding to an area density of 1.28 × 107 pillass/mm2) as defined by the nanoimprinting mould, while the lateral facet-to-facet dimensions is approximately 160 nm, a reduction from the approximately 180-nm pores in the NIL mould.
Particularly in the case of PFJ-OA, they noted that it is important to be aware of the potential for exaggerated thinning of the patella lateral facet; adequate under-resection of this facet and component placement in the medial border of the patella may be required to maintain bone stock and adequate patellar tracking.
Significant lateral facet patellofemoral arthritis (grade IV) even in association with medial facet and femoral sulcus involvement is not a contraindication to this surgical approach.
