The Hip: Preservation, Replacement and Revision

Anatomy of Patella

- Discussion:
    - sesamoid bone w/ in quadriceps tendon;
    - cartilaginous posterior surface is divided by a rounded vertical ridge into a larger, lateral portion for articulation w/ lateral condyle of femur and smaller
           medial portion for articulation w/ medial condyle of femur;
    - w/ increasing knee flexion, contact pressure moves proximally on patella up to superior pole and onto quadriceps tendon;
    - articular surface of patella, varying in thickness from approximately 2 to 5.5 mm, is divided into 7 fascets;
           - medial and lateral facets are divided into = 1/3 sections;
           - superiorly and inferiorly, with the 7th facet being the most medial portion called the odd facet;
    - Wiberg: 3 shapes based on position of vertical ridge;
           - type I:  there are roughly = medial and lateral facets
           - type II  most common: medial facet is only 1/2 size of lat. facet;
           - type III medial facet is so far medial that the central ridge is barely noticable;

- Blood Supply:
    - blood supply to patella originates from as many as 12 nutrient arteries at the inferior pole,
           which run upward on the anterior surface of the bone in a series of furrows;
    - may arise from mid patellar vessels penetrating middle 1/3 of anterior surface & inferior pole vessels that anastomose at inferior pole of patella;
    - geniculate system feeds these primary vessels;
           - anterior tibial recurrent vessels
           - inferior medial genicular
           - inferior lateral genicular
    - references:
           - Quantitative and qualitative assessment of bone perfusion and arterial contributions in a patellar fracture model using gadolinium-enhanced magnetic resonance imaging: a cadaveric study.
Vascular anatomy of the patella: implications for total knee arthroplasty surgical approaches.
Safe zone for the descending genicular artery in the midvastus approach to the knee.

Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Thursday, February 26, 2015 10:22 am