Knee Extensor Mechanism Pathology: A case based review.

Congress:

ESSR 2017

Poster Number:

P-0176

Type:

Educational Poster

Keywords:

Trauma, Acute, Diagnostic procedure, MR, Digital radiography, CT, Musculoskeletal system, Extremities, Bones

Authors:

R. E. Tarud Sabbag¹, N. Anand², C. Boyd¹, H. Su¹; ¹Morristown, NJ/US, ²Morristown , NJ/US

DOI:

10.1594/essr2017/P-0176

DOI-Link:

https://dx.doi.org/10.1594/essr2017/P-0176

Fig. 1: Sagittal PD Fat Sat MR of the knee demonstrates an avulsion of the quadriceps...

Fig. 2: Sagittal T2 Fat Sat MR(A) and axial PD Fat Sat MR (B) of the knee demonstrates...

Fig. 3: A. Sagittal PD Fat sat MR of the knee demonstrates an unfused anterior tibial...

Fig. 4: Sagittal T2 Fat Sat MR of the knee demonstrates intense marrow edema of the...

Learning objectives

Review the anatomy andfunction of the knee extensor mechanism in detail. Identify common pathology involving the knee extensor mechanism. Discuss  imaging andpathology associated with the knee extensor mechanism.

Background

The extensor mechanism of the knee allows us to extend  our knee joint, which  is crucial for maintaining a  standing position, rising from a sitting position, and ascending/descending stairs. The extensor mechanism consists of  various anatomical structures such as the quadriceps muscle, patella, patellar tendon, anterior fat pad, and medial and  lateral retinaculum complexes. Pathology involving the extensor mechanism can be due to pathologic conditions of the patella (such as fractures or dislocations),  avulsion fractures of the patellar tendon attachments (such as Osgood-Schlatter syndrome), disruptions...

Imaging findings OR Procedure Details

Quadriceps Injury The anterior thigh is comprised of 4 muscles: the rectus femoris, vastus medialis, vastus lateralis, and vastus intermedius. These muscles insert in the patella by the quadriceps tendon. Tear of the quadriceps occurs when any of these four muscles or its conjoined tendon are involved. Injuries present as tendinopathy, intramuscular injury, partial or complete disruption of the distal myotendinous units of the quadriceps muscle. Involves most commonly the vastus intermedius and usually occurs at or proximal to the patellar insertion. Presentation Patient presents...

Conclusion

The extensor mechanism is a vital component of our knee joint and is involved in our biomechanics. It is susceptibleto different pathologic processes. Understanding extensor mechanism pathology will aid radiologists in diagnosing knee injuries accurately.

References

Della Rocca G. Displaced Patella Fractures. Journal of Knee Surgery. 2013;26(05):293-300. doi:10.1055/s-0033-1353988. Dupuis C, Westra S, Makris J, Wallace E. Injuries and Conditions of the Extensor Mechanism of the Pediatric Knee. RadioGraphics. 2009;29(3):877-886. doi:10.1148/rg.293085163. Gao G, Mahadev A, Lee E. Sleeve Fracture of the Patella in Children. Journal of Orthopaedic Surgery. 2008;16(1):43-46. doi:10.1177/230949900801600111. Gilmore J, Clayton-Smith Z, Aguilar M, Pneumaticos S, Giannoudis P. Reconstruction techniques and clinical results of patellar tendon ruptures: Evidence today. The Knee. 2015;22(3):148-155. doi:10.1016/j.knee.2014.10.007. Hak D, Sanchez A, Trobisch P. Quadriceps...