The Posterior Condylar Offset Ratio

Important Differences Exist in Posterior Condylar Offsets in an Osteological Collection of 1,058 Femurs

“…We suspect this is due to the variable nature of the intercondylar fossa. We identified that the medial and lateral PCOs are not symmetrical, corroborating early work suggesting medial PCO is greater than lateral PCO [6,22,23]. While the significance of this is unclear, some authors have suggested that existing arthroplasty systems do not adequately account for a non-uniform PCO [2].…”

“…Johal et al [23] found a smaller PCO in Chinese individuals compared to a Western population, corroborating the notion that differences in PCO exist between races. Wang et al studied 50 male and 50 female Chinese patients and demonstrated that the average PCO of Chinese females (25.80 mm ± 2.71 mm) was significantly smaller than that of Chinese males (27.32 mm ± 2.34 mm), but these authors did not standardize their measurements using the width of the femoral diaphysis and had a very limited population [26].…”

“…Conclusions regarding the PCO of other races cannot be made from this study, although PCO in the Asian population has been well-reported [20,23,26]. Our study may have been limited by the paucity of female femurs available, although a power analysis was performed suggesting adequate sample size.…”

Posterior Condylar Cartilage Thickness and Posterior Condylar Offset of the Femur: A Magnetic Resonance Imaging Study

“…9,10 Most anatomic studies are conducted in arthritic individuals in whom cartilage and even bony erosion have taken place, and measurement is usually made by radiography and computed tomography that may underestimate normal PCO. [9][10][11][12][13] Our results suggested that pre-TKA templating may underestimate the normal PCO by approximately 2 mm, due to the cartilage. PCC remnants can alter femoral component rotation when the posterior condylar axis is referenced intra-operatively.…”

The posterior condylar offset ratio and femoral anatomy in anterior versus posterior referencing total knee arthroplasty

“…The assessment of these changes can be made radiographically using the posterior condylar offset ratio (PCOR) [13], a revision of the original posterior condylar offset (PCO) proposed by Bellemans et al for studying range of movement [14]. Being dimensionless, the PCOR corrects the bias introduced by normal joint size distribution naturally occurring in patients and the non-standardized magnification of each radiograph [15]; in addition, it offers a fast and reproducible way, independent of referencing system, for gauging alterations in condylar offset resulting from implant fit [16].…”