Recognition and initial management of lateral patellar dislocations
- Brian R Moore, MD
Brian R Moore, MD
- Associate Professor of Emergency Medicine
- University of New Mexico Health Sciences Center
- Joan Bothner, MD
Joan Bothner, MD
- Professor of Pediatrics and Emergency Medicine
- University of Colorado School of Medicine
- Section Editors
- Anne M Stack, MD
Anne M Stack, MD
- Section Editor — Pediatric Procedures
- Associate Professor, Department of Pediatrics
- Harvard Medical School
- Albert C Hergenroeder, MD
Albert C Hergenroeder, MD
- Section Editor — Pediatric Sports Medicine; Adolescent Sports Medicine
- Professor & Chief of Pediatrics, Adolescent Medicine and Sports Medicine
- Baylor College of Medicine
- Allan B Wolfson, MD
Allan B Wolfson, MD
- Section Editor — Adult Procedures
- Professor of Emergency Medicine
- University of Pittsburgh
- Deputy Editor
- James F Wiley, II, MD, MPH
James F Wiley, II, MD, MPH
- Senior Deputy Editor — Adult and Pediatric Emergency Medicine
- Senior Deputy Editor — Primary Care Sports Medicine (Adolescents and Adults)
- Clinical Professor of Pediatrics and Emergency Medicine/Traumatology
- University of Connecticut School of Medicine
Lateral patellar dislocation occurs most often in the second and third decades of life [1-3]. The usual mechanism of injury is a twisting movement about the flexed knee as may occur during dancing, gymnastics, or the swinging of a baseball bat [4,5]. Direct trauma to the knee also may cause patellar dislocation. Lateral dislocation is most common; other types of patellar dislocations, including intra-articular dislocations, are rare [1,6]. (See 'Terminology' below and 'Mechanisms of injury' below.)
The clinical manifestations, diagnosis, and management of lateral patellar dislocations are reviewed here. Knee (tibiofemoral dislocations) and other knee injuries in young athletes are discussed separately. (See "Knee (tibiofemoral) dislocation and reduction" and "Approach to acute knee pain and injury in children and skeletally immature adolescents" and "Approach to chronic knee pain or injury in children or skeletally immature adolescents".)
Patellar dislocation is distinct from patellar subluxation or knee dislocation as follows:
●Patellar dislocation – Patellar dislocations most commonly are lateral, although medial or superior dislocations are described. The patella is displaced from the trochlear groove. Intra-articular dislocations with lodging of the patella within the joint space may be superior, inferior, or vertical. (See 'Mechanisms of injury' below.)
●Patellar subluxation – Patellar subluxation describes excessive lateral movement of the patella and may occur as a result of trauma or in patients with laxity. The patella still tracks within the trochlear groove but may cause discomfort and a feeling of instability. (See 'Anatomy' below.)
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- MECHANISMS OF INJURY
- Predisposing conditions
- CLINICAL FEATURES AND DIAGNOSIS
- DIFFERENTIAL DIAGNOSIS
- Patellar subluxation
- Superior patellar dislocation
- Intra-articular patellar dislocation
- Patellar fracture
- Quadriceps tendon rupture
- Patellar tendon rupture
- INDICATIONS FOR ORTHOPEDIC REFERRAL OR CONSULTATION
- REDUCTION OF LATERAL DISLOCATIONS
- Postreduction evaluation
- POSTREDUCTION MANAGEMENT
- ADDITIONAL RESOURCES