Superior Dislocation of the Patella

Superior dislocation of the patella
Image shows the patient's left knee upon arrival at the ED, after a fall from a bicycle (a). It is possible to notice that there is no bulging in the anterior region of the knee found in the VDP. SDP is suspected based on the attachment of the distal end of the patella to the proximal end of the trochlea (arrow). The high riding patella needs to be distinguished from a patellar tendon rupture (b). Radiograph of the left knee obtained after the procedure shows successful reduction (c). ED: emergency department; SDP: superior dislocation of the patella.
  • Superior dislocation of the patella (SDP) is an often misdiagnosed condition, confused with rupture of the patellar tendon based on radiographic findings.
  • Therefore, to differentiate between the two, a careful history and clinical examination are important. Treatment includes immediate close reduction. Whereas in case of a ruptured tendon surgical treatment is required.
  • This case is of the youngest patient with a known case of SDP.

This article describes the case of a 19-year-old female patient who presented to the emergency with severe pain and an anteromedial skin bruise on her left knee. In addition, her knee locked in full extension, diagnosed with superior dislocation of the patella. The woman’s history revealed that she had fallen from a bicycle and hit her knee against a street guide.

Radiographic examination showed a superior displacement of the patella. In addition, the inferior articular surface engaged the proximal articular surface of the trochlea. Doctors administered the patient 2% lidocaine hydrochloride intra-articularly for pain. The patellofemoral joint was reduced in relation to the femur. A plain radiograph was used for confirmation.

The patient’s knee was immobilised for a week to ensure comfort. 10 days after the procedure, the patient was pain free with no limitations in movement. In addition, there were no symptoms either.

Superior dislocation of the patella

Superior dislocation of the patella is a rare condition that is commonly associated with degenerative changes. Similarly, it also presents secondary to the presence of osteophytes. And the peak incidence is observed during the sixth decade of life. The distal articular edge of the patella locks the knee in full extension by engaging in the proximal articular edge of the trochlea.

Although the condition is rare, urgent treatment is required. Patients with this condition generally present to the emergency with complaints of pain and restricted movement.


Superior Dislocation of the Patella in a Young Patient without Osteophytes: A Case Report with Discussion about Differential Diagnosis

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Dr. Aiman Shahab is a dentist with a bachelor’s degree from Dow University of Health Sciences. She is an experienced freelance writer with a demonstrated history of working in the health industry. Skilled in general dentistry, she is currently working as an associate dentist at a private dental clinic in Karachi, freelance content writer and as a part time science instructor with Little Medical School. She has also been an ambassador for PDC in the past from the year 2016 – 2018, and her responsibilities included acting as a representative and volunteer for PDC with an intention to make the dental community of Pakistan more connected and to work for benefiting the underprivileged. When she’s not working, you’ll either find her reading or aimlessly walking around for the sake of exploring. Her future plans include getting a master’s degree in maxillofacial and oral surgery, settled in a metropolitan city of North America.


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