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Knee

Patellar Dislocation Introduction and Diagnosis

After recent prominence in the media due to a prominent quarterback in the NFL suffering a patellar dislocation, a background of this injury along with which imaging modalities are used will be reviewed this week.

J
John Kiel
Sports Medicine Physician Β· November 24, 2019 Β· 3 min read

Overview

After recent prominence in the media due to a prominent quarterback in the NFL suffering a patellar dislocation, a background of this injury along with which imaging modalities are used will be reviewed this week. Many sports fans were watching and questioning the recovery time and whether surgery is needed for what some call a β€œknee dislocation.” A patellar dislocation occurs when the patella disengages completely from the trochlear or femoral groove. It can reduce on its own and sometimes will need manually reduced.

Symptoms

The overall incidence is around 8 to 23 per 100,000 and has the highest among adolescents aged 14 to 18 years. Males and females seem to be affected equally. Patellar dislocations most commonly occur in the lateral direction.

Causes and Risk Factors

Medial dislocations, intra-articular and superior dislocations are rare. The vastus medialis obliquus or VMO is the most distal portion of the quadriceps muscle and exerts a medially directed force that helps keep the patella in position. Weakness or atrophy of this muscle makes dislocation more likely.

Treatment Options

The medial retinaculum is reinforced by the medial patellofemoral ligament, or MPFL, which prevents excessive lateral movement of the patella. Other risk factors include an increased Q angle, patella alta or high riding patella, trochlear dysplasia, excessive lateral patellar tilt and lateral femoral condyle hypoplasia [1, 9]. The relationship of the MPFL to other structures.VML: vastus medialis longus, AM: adductor magnus, VMO: vastus medialis obliquus, PMC: posteromedial capsule;MPFL: medial patellofemoral ligament; SMCL: superficial band of medial collateral ligament.

Recovery

History may differ depending on the mechanism of injury, but most describe pain and potentially a noticeable deformity of the knee. This is usually preceded by direct trauma to the knee or a sudden change in direction. Many also describe a sense of giving way or instability when the dislocation occurs.

When to See a Doctor

If you are experiencing symptoms that may be related to patellar dislocation introduction and diagnosis, it is important to see a sports medicine physician. Early evaluation and treatment typically lead to better outcomes. Do not ignore pain or symptoms that are limiting your activity.

*This article is for educational purposes only and does not substitute for professional medical advice. Always consult a qualified healthcare provider.*

Knee
J
John Kiel
Sports Medicine Physician
Sports Medicine Review contributor

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