| Patellar dislocation | |
|---|---|
| Other names | Kneecap dislocation, dislocated kneecap |
 | |
| X-ray showing a patellar dislocation, with the patella out to the side. | |
| Specialty | Emergency medicine, orthopedics |
| Symptoms | Knee is partly bent, painful and swollen[1][2] |
| Complications | Patella fracture, arthritis[3] |
| Usual onset | 10 to 17 years old[4] |
| Duration | Recovery within 6 weeks[5] |
| Causes | Bending the lower leg outwards when the knee is straight, direct blow to the patella when the knee is bent[1][2] |
| Risk factors | High riding patella, family history, loose ligaments[1] |
| Diagnostic method | Based on symptoms, X-rays[2] |
| Treatment | Reduction, splinting, physical therapy, surgery[1] |
| Medication | Pain medication[3] |
| Prognosis | ~30% risk of recurrence[4] |
| Frequency | 6 per 100,000 per year[4] |
A patellar dislocation is a knee injury in which the patella (kneecap) slips out of its normal position.[5] Often the knee is partly bent, painful and swollen.[1][2] The patella is also often felt and seen out of place.[1] Complications may include a patella fracture or arthritis.[3]
A patellar dislocation typically occurs when the knee is straight and the lower leg is bent outwards when twisting.[1][2] Occasionally, it occurs when the knee is bent and the patella is struck directly.[1] Commonly associated sports include soccer, gymnastics, and ice hockey.[2] Dislocations nearly always occur away from the midline.[2] Diagnosis is typically based on symptoms and supported by X-rays.[2]
Reduction is generally done by pushing the patella towards the midline while straightening the knee.[1] After reduction, the leg is generally splinted in a straight position for a few weeks.[1] This is then followed by physical therapy.[1] Surgery after a first dislocation is generally of unclear benefit.[6][4] Surgery may be indicated in those cases where a fracture occurs within the joint or where the patella has repeatedly dislocated.[3][4][5]
Patellar dislocations occur in about 6 per 100,000 people per year.[4] They make up about 2% of knee injuries.[1] It is most common in those 10 to 17 years old.[4] Rates in males and females are similar.[4] Recurrence after an initial dislocation occurs in about 30% of people.[4]
- ^ a b c d e f g h i j k l Ramponi D (2016). "Patellar Dislocations and Reduction Procedure". Advanced Emergency Nursing Journal. 38 (2): 89–92. doi:10.1097/TME.0000000000000104. PMID 27139130. S2CID 42552493.
- ^ a b c d e f g h Dath R, Chakravarthy J, Porter KM (2006). "Patella dislocations". Trauma. 8 (1): 5–11. doi:10.1191/1460408606ta353ra. ISSN 1460-4086. S2CID 208269986.
- ^ a b c d Cite error: The named reference
duthonwas invoked but never defined (see the help page). - ^ a b c d e f g h i Jain NP, Khan N, Fithian DC (March 2011). "A treatment algorithm for primary patellar dislocations". Sports Health. 3 (2): 170–4. doi:10.1177/1941738111399237. PMC 3445142. PMID 23016004.
- ^ a b c "Patellar Dislocation and Instability in Children (Unstable Kneecap)". OrthoInfo - AAOS. March 2014. Archived from the original on 18 June 2017. Retrieved 16 October 2017.
- ^ Smith TO, Gaukroger A, Metcalfe A, Hing CB (24 January 2023). "Surgical versus non-surgical interventions for treating patellar dislocation". The Cochrane Database of Systematic Reviews. 1 (1): CD008106. doi:10.1002/14651858.CD008106.pub4. ISSN 1469-493X. PMC 9872769. PMID 36692346.