The Merchant view is a special X-ray view of the knee that shows clearly the position of the patella in the underlying groove of the trochlea with the muscles at rest.
Page updated March 2024 by Dr Sheila Strover (Clinical Editor)
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Quote from peer-reviewed paper:
"....a sulcus angle measuring more than 145° in a Merchant view knee radiograph with the knee in 45° knee flexion and the beam at 30° inclination caudal down the patellar femoral joint is characteristic of trochlear dysplasia"
Citation: Kazley JM, Banerjee S. Classifications in Brief: The Dejour Classification of Trochlear Dysplasia. Clin Orthop Relat Res. 2019 Oct;477(10):2380-2386. doi: 10.1097/CORR.0000000000000886. PMID: 31393338; PMCID: PMC6999944.
How does a Merchant view compare to a weight-bearing X-ray?
In the Merchant view the patient lies at rest and any distortion of the anatomy that might be contributed from bearing weight is not appreciated.
So evaluation of any closure of the joint space from osteoarthritis or meniscal degeneration would need a weight-bearing view, such as the Rosenberg view.
Can the TT-TG distance be measured on a Merchant view?
Usually a CT or MRI scan is ordered to measure the TT-TG distance, or how out of alignment the patellar tendon is, but in a large number of cases a Merchant view will allow an easier and more affordable way of making this measurement.
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Quote from peer-reviewed paper:
"The tibial tubercle could be identified on Merchant radiograph in...81.7%....Merchant TT-TG strongly correlates with MRI TT-TG but measured 5-8 mm smaller...."
Citation: Bernholt D, Lamplot JD, Eutsler E, Nepple JJ. Utility of Merchant View Radiographs for Assessment of TT-TG: A Comparison to MRI. Orthop J Sports Med. 2018 Jul 27;6(7 suppl4):2325967118S00075. doi: 10.1177/2325967118S00075. PMCID: PMC6083762.
Relevant content -
Part of a course -
2010 - Imaging and X-rays for patellofemoral pain - by Dr Ronald Grelsamer (Knee Surgeon)
2006 - X-ray Imaging for Patellar Malalignment - by Dr Ronald Grelsamer (Knee Surgeon)