Case reportSuperior dislocation of the patella — a rare but important differential diagnosis of acute knee pain — a case report and review of the literature
Introduction
Superior dislocation of the patella is a rare, but important, differential diagnosis of acute knee pain, which is important to recognise early to avoid unnecessary pain for the patient and incorrect management. We present a case report and review of the literature.
Section snippets
Case report
A 55 year old bus driver, presented with severe left knee pain. Whilst on a step ladder he felt the left knee ‘give way’, and was unable to move it. He had multiple excisions and bone grafting of a recurrent giant cell tumour of the left medial proximal tibia 12 years previously, and was awaiting a total knee replacement. The patella appeared superiorly displaced and tilted, leaving a hollowing in the infra-patellar region (Fig. 1).
He would not allow the knee to be flexed. A-P and lateral plain
Comment
By far the most common dislocation of the patella is in a lateral direction. This is recognized by a lateral lying patella and haemarthrosis [1], confirmed by X-ray, including a tangential view to exclude any large osteochondral fractures.
However, there are other types of patellar dislocation which are important to recognise. Intra-articular [2], inferior [3], and superior [1] dislocations have all been described.
Intra-articular dislocations usually occur in adolescent boys, and involve the
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Cited by (16)
Closed Emergency Department Reduction of a Superior Patellar Dislocation After Blunt Trauma
2018, Journal of Emergency MedicineCitation Excerpt :Vertical rotational dislocations are less common and occur when the patella rotates around its longitudinal axis and remains wedged in the intercondylar groove or on the outer surface of the lateral femoral condyle (3). Superior dislocations are a rare entity, and an extensive literature review of the published literature revealed only 15 other cases, 2 of which were traumatic (1,2,4–14). The commonly described mechanism for superior dislocations is a posteriorly directed blow to the knee when it is in near complete extension causing displacement of the inferior pole of the patella and locking the patella on osteophytes (1,7).
Superior dislocation of the patella: Case report and review of the literature
2013, Journal of Emergency MedicineCitation Excerpt :Usually these dislocations are easily reducible. With a relaxed patient who has had adequate pain relief, an upward push to the patella with mediolateral pressure usually unlocks the osteophytes and brings the patella into position (1–3,8,9,13–15). This method has been successful in all but one case reported (16).
A rare cause of an acutely locked knee joint: superior patellar dislocation
2021, UnfallchirurgSuperior dislocation of the patella: a pathognomonic finding and review of literature
2017, Skeletal Radiology