View source for Hip dislocation

{{Short description|Orthopedic injury}}
{{About|acute hip dislocation|developmental hip dysplasia|Hip dysplasia}}
{{Use dmy dates|date=July 2019}}
{{Infobox medical condition (new)
| name          = Dislocation of hip
| synonyms      =
| image         = HipdisX.png
| caption       = X-ray showing a joint dislocation of the left hip.
| pronounce     =
| field         = [[Orthopedics]]
| symptoms      = Hip pain, trouble moving the hip<ref name=OI2014/>
| complications = [[Avascular necrosis of the hip]], [[arthritis]]<ref name=OI2014/>
| onset         =
| duration      =
| types         = Anterior, posterior<ref name=OI2014/>
| causes        = Trauma,<ref name=OI2014/> [[hip dysplasia]]
| risks         =
| diagnosis     = Confirmed by [[X-rays]]<ref name="Bee2016">{{cite journal | vauthors = Beebe MJ, Bauer JM, Mir HR | title = Treatment of Hip Dislocations and Associated Injuries: Current State of Care | journal = The Orthopedic Clinics of North America | volume = 47 | issue = 3 | pages = 527–49 | date = July 2016 | pmid = 27241377 | doi = 10.1016/j.ocl.2016.02.002 }}</ref>
| differential  = [[Hip fracture]], [[hip dysplasia]]<ref name=Bla2016/>
| prevention    = Seat-belts<ref name=OI2014/>
| treatment     = [[Reduction (orthopedic surgery)|Reduction]] of the hip carried out under [[procedural sedation]]<ref name=OI2014/>
| medication    =
| prognosis     = Variable<ref name=Ken2015/>
| deaths        =
}}
<!-- Definition and Cause -->
A '''hip dislocation''' is when the thighbone ([[femur]]) separates from the hip bone ([[pelvis]]).<ref name="OI2014">{{cite web|date=June 2014|title=Hip Dislocation|url=https://orthoinfo.aaos.org/en/diseases--conditions/hip-dislocation|access-date=7 June 2018|website=AAOS}}</ref> Specifically it is when the ball–shaped head of the femur ([[femoral head]]) separates from its cup–shaped socket in the hip bone, known as the [[acetabulum]].<ref name=OI2014/> The joint of the femur and pelvis ([[hip joint]]) is very stable, secured by both bony and soft-tissue constraints.<ref name="OI2014" /><ref name="Ken2015" /><ref name=":1">{{Cite web|title=Hip Dislocation - Trauma - Orthobullets|url=https://www.orthobullets.com/trauma/1035/hip-dislocation|access-date=2021-03-17|website=www.orthobullets.com}}</ref> With that, dislocation would require significant force which typically results from [[Major trauma|significant trauma]] such as from a [[motor vehicle collision]] or from a [[Falling (accident)|fall]] from elevation.<ref name="OI2014" /> Hip dislocations can also occur following a [[hip replacement]] or from a developmental abnormality known as [[hip dysplasia]].<ref>{{cite book|last1=Callaghan|first1=John J.|url=https://books.google.com/books?id=-fwULYB1gJIC&pg=PA1032|title=The Adult Hip|last2=Rosenberg|first2=Aaron G.|last3=Rubash|first3=Harry E.|date=2007|publisher=Lippincott Williams & Wilkins|isbn=9780781750929|page=1032|language=en|name-list-style=vanc}}</ref><!-- Treatment and Management -->

Hip dislocations are classified by fracture association and by the positioning of the dislocated femoral head.<ref name=":4" /><ref name=":3" /> A posteriorly positioned head is the most common dislocation type.<ref name=":1" /> Hip dislocations are a medical emergency, requiring prompt placement of the femoral head back into the acetabulum ([[Reduction (orthopedic surgery)|reduction]]).<ref name=":5">{{Cite journal|last1=Foulk|first1=David M.|last2=Mullis|first2=Brian H.|date=April 2010|title=Hip Dislocation: Evaluation and Management|url=https://dx.doi.org/10.5435/00124635-201004000-00003|journal=American Academy of Orthopaedic Surgeon|language=en|volume=18|issue=4|pages=199–209|doi=10.5435/00124635-201004000-00003|pmid=20357229|s2cid=24913294|issn=1067-151X|url-access=subscription}}</ref> This reduction of the femoral head back into the hip socket is typically done under sedation and without surgery, through maneuvers including [[Traction (orthopedics)|traction]] on the thighbone in line with the dislocation.<ref name=":5" /> If this is unsuccessful or if there is an associated fracture in need of repair, surgery is required.<ref>{{Cite web|date=2018-03-02|title=Recovering from Hip Dislocation|url=https://ccoe.us/hip/recovering-from-hip-dislocation/|access-date=2021-03-23|website=Colorado Center of Orthopaedic Excellence|language=en}}</ref> It often takes 2–3 months for a dislocated hip to fully heal, and it can take even longer depending on associated injuries such as fracture.<ref name=":8">{{Cite web|last=Publishing|first=Harvard Health|title=Traumatic Dislocation of the Hip|url=https://www.health.harvard.edu/a_to_z/traumatic-dislocation-of-the-hip-a-to-z|access-date=2021-03-23|website=Harvard Health|date=17 May 2019 }}</ref><!-- Diagnosis -->

Typically, people with hip dislocations present with severe pain and an inability to move the affected leg.<ref name="OI2014" /><ref name="Ken2015" /> Diagnosis is made by physical exam and plain X-rays of the hips. A CT scan is recommended following reduction to rule out complications. Complications include [[osteonecrosis]], [[Hip fracture|femoral head fractures]], and posttraumatic [[osteoarthritis]].<ref>{{Citation|last1=Masiewicz|first1=Spencer|title=Posterior Hip Dislocation|date=2021|url=http://www.ncbi.nlm.nih.gov/books/NBK459319/|work=StatPearls|place=Treasure Island (FL)|publisher=StatPearls Publishing|pmid=29083669|access-date=2021-03-17|last2=Mabrouk|first2=Ahmed|last3=Johnson|first3=Dean E.}}</ref><ref name=":11">{{Citation|last1=Graber|first1=Matthew|title=Anterior Hip Dislocation|date=2021|url=http://www.ncbi.nlm.nih.gov/books/NBK507814/|work=StatPearls|place=Treasure Island (FL)|publisher=StatPearls Publishing|pmid=29939591|access-date=2021-03-17|last2=Marino|first2=Dominic V.|last3=Johnson|first3=Dean E.}}</ref>

<!-- Epidemiology and History -->
Males are affected more often than females.<ref name="Bla2016">{{cite book |last1=Blankenbaker |first1=Donna G. |last2=Davis |first2=Kirkland W.| name-list-style = vanc  |title=Diagnostic Imaging: Musculoskeletal Trauma E-Book |date=2016 |publisher=Elsevier Health Sciences |isbn=9780323442954 |page=495 |url=https://books.google.com/books?id=o0DUDAAAQBAJ&pg=PA495 |language=en}}</ref> Traumatic dislocations occurs most commonly in those 16 to 40 years old.<ref name="Ken2015">{{Cite book|last=Egol|first=Kenneth A, Koval KJ, Zuckerman JD|title=Handbook of fractures|publisher=Wolters Kluwer Health|year=2010|isbn=978-1605477602|edition=4th|location=Philadelphia|page=Chapter 27|oclc=|name-list-style=vanc}}</ref> Half of all hip dislocations are accompanied by a fracture.<ref name="Ken2015" /> The condition was first described in the medical press in the early 1800s.<ref name=":9">{{Cite journal|last1=Beebe|first1=Michael J.|last2=Bauer|first2=Jennifer M.|last3=Mir|first3=Hassan R.|date=July 2016|title=Treatment of Hip Dislocations and Associated Injuries|url=http://dx.doi.org/10.1016/j.ocl.2016.02.002|journal=Orthopedic Clinics of North America|volume=47|issue=3|pages=527–549|doi=10.1016/j.ocl.2016.02.002|pmid=27241377|issn=0030-5898|url-access=subscription}}</ref><ref name=":10">{{Cite journal|last=Yeatman|first=John C.|date=June 1815|title=Case of Injury of the Hip Confounded with Dislocation, and Fracture of the Neck of the Thigh-Bone|journal=The London Medical and Physical Journal|volume=33|issue=196|pages=469–471|issn=0267-0259|pmc=5581659|pmid=30493665}}</ref>
{{TOC limit}}

== Classifications ==
Dislocations are categorized as simple if there is no associated fracture, and complex if there is.<ref name=":1" /> In addition, hip dislocations are classified depending on the location of the head of the femur as follows:

=== Posterior dislocation ===
''Posterior dislocations'' is when the femoral head lies posteriorly after dislocation.<ref name=":1" /> It is the most common pattern of dislocation accounting for 90% of hip dislocations,<ref name=":1" /> and those with an associated fracture are categorized by the [[Thompson and Epstein classification]] system, the Stewart and Milford classification system, and the [[Pipkin classification|Pipkin]] system (when associated with femoral head fractures).<ref name=":4" /><ref name=":3">{{cite journal|vauthors=Goddard NJ|date=August 2000|title=Classification of traumatic hip dislocation|journal=Clinical Orthopaedics and Related Research|volume=377|issue=377|pages=11–4|doi=10.1097/00003086-200008000-00004|pmid=10943180}}</ref>

=== Anterior dislocation ===
''Anterior dislocations'' is when the femoral head lies anteriorly after dislocation. Anterior dislocations are subdivided into two types being inferior (obturator) dislocation and superior (iliac or pubic) dislocation.<ref name="Ken2015" /><ref name=":1" /> There is also a Thompson and Epstein classification system for anterior hip dislocations.<ref name=":3" />

To note, ''Central dislocation'' is an outdated term for displacement of the femoral head towards the body's center into a fractured acetabulum and is no longer used.<ref name=":4">{{Cite book|last1=Browner|first1=Bruce D|title=Skeletal trauma : basic science, management, and reconstruction|last2=Jupiter|first2=Jesse B|last3=Krettek|first3=Christian|last4=Anderson|first4=Paul A|date=9 December 2014|isbn=9781455776283|edition=Fifth|location=Philadelphia, PA|oclc=898159499|name-list-style=vanc}}</ref> Moreover, the term "congenital" dislocation is no longer recommended, except for very rare conditions, in which there is a "[[Teratology|teratologic]]" fixed dislocation location present at birth.<ref name=":0">{{Cite book|title=Essentials of musculoskeletal care|date=2010|publisher=American Academy of Orthopaedic Surgeons|others=Sarwark, John F.|isbn=9780892035793|location=Rosemont, Ill.|oclc=706805938}}</ref>

== Signs and symptoms ==
The affected leg is usually extremely painful, precluding weight-bearing and movement.<ref name="Ken2015" /><ref name=":2">{{Cite web|title=Hip Dislocation-OrthoInfo - AAOS|url=http://orthoinfo.aaos.org/topic.cfm?topic=a00352|access-date=1 October 2017|website=orthoinfo.aaos.org}}</ref> Nerve injuries also can accompany dislocations, necessitating careful neurovascular examination.<ref name="Ken2015" /><ref name=":1" /> Deformity is also present, which is based on concomitant injuries and the type of dislocation:

=== Posterior dislocation ===
For posterior dislocation, the affected limb will be in a position of flexion, adduction, and internal rotation.<ref name="Ken2015" /><ref name=":1" /><ref name=":0" /> This is to say, the affected leg will be bent upwards at the hip, while being shifted and pointed towards the middle of the body.<ref name=":8" /><ref name=":2" /> [[Sciatic nerve]] injury is also present in 8%-20% of cases, conferring numbness and weakness to aspects of the lower leg.<ref name="Ken2015" /><ref name=":1" />

=== Anterior dislocation ===
For anterior dislocation, the affected limb will be in a position of abduction and external rotation.<ref name="Ken2015" /><ref name=":1" /><ref name=":0" /> The degree of flexion depends on whether it is a superior or inferior dislocation, with the former resulting in hip extension and the latter, hip flexion.<ref name="Ken2015" /><ref name=":1" /><ref name=":11" /> This is to say that with superior and inferior anterior dislocations, the affected leg will be bent at the hip backwards and upwards respectively, while being shifted and pointed away from the body. Femoral nerve palsies can also be present, conferring leg numbness and weakness, however are uncommon.<ref name=":0" />

== Mechanism ==

=== Functional anatomy ===

The hip joint includes the [[articulation (anatomy)|articulation]] of the spherical femoral head (of femur) and the concave acetabulum (of pelvis). It forms a [[ball-and-socket joint]] that is encased by an articular capsule, reinforced and stabilized by muscle, [[tendon]], and [[ligament]]s.<ref>{{Cite web|title=Understanding your hip|url=https://www.allinahealth.org/health-conditions-and-treatments/health-library/patient-education/total-hip-replacement/general-information/understanding-your-hip#:~:text=Muscle%20and%20ligaments%20hold%20your,you%20can%20walk%20without%20pain.|access-date=2021-03-22|website=www.allinahealth.org|language=en}}</ref> Even so, the joint is quite flexible in movement, allowing three [[Degrees of freedom (mechanics)|degrees of freedom]].<ref>{{Cite web|title=How Does a Hip Joint Move?|url=https://www.brainlab.org/get-educated/hip/hip-anatomy/how-does-your-hip-joint-move/|access-date=2021-03-22|website=Brainlab.org}}</ref>

Major ligaments conferring stability to the hip joint include the [[iliofemoral ligament]], the [[ischiofemoral ligament]], the [[pubofemoral ligament]], and the [[Ligament of head of femur|ligament of the head of the femur]].<ref name=":6">{{Cite web|title=Hip joint - Joints health|url=https://joints-health.co.uk/hip-joint|access-date=2021-03-22|website=joints-health.co.uk|language=en}}</ref> The former three ligaments form the [[zona orbicularis]] or annular ligament which encases the femoral neck, stabilizing the joint capsule.<ref name=":6" /> The strength of a healthy hip, reinforced and stabilized by the aforementioned structures can withstand over 1000 lbs. of force.<ref name=":6" />

=== Cause ===
With this, to dislocate a healthy hip requires a great deal of [[force]].<ref name=":1" /> About 65% of cases are related to motor vehicle collisions, with falls from elevation and sports injuries causing the majority of the rest.<ref name=":1" /> Moreover, wear and tear of the body with aging increases the older population's susceptibility to hip dislocation.<ref name="autogenerated1">{{cite web|url=http://orthoinfo.aaos.org/topic.cfm?topic=A00352 |title=Hip Dislocation-OrthoInfo - AAOS |publisher=Orthoinfo.aaos.org |date=1 June 2014 |access-date=1 March 2015}}</ref>

''Posterior dislocations'' happen with direct trauma to a bent ([[Flexion|flexed]]) knee as is the case with a dashboard injury in a motor vehicle accident.<ref name="Ken2015" /><ref name=":1" /> The positioning of the hip at the time of impact determines associated injuries, with [[Abduction (anatomy)|abduction]] of the hip making a complex hip dislocation more likely, while [[adduction]] and flexion of the hip favors a simple hip dislocation.{{citation needed|date=June 2022}}

''Anterior dislocations'' happen with trauma forcing [[external rotation]] and abduction of the hip.<ref name="Ken2015" /><ref name=":1" /> In the setting of forced external rotation and abduction of the hip, the hip flexed and [[Extension (anatomy)|extended]] leads to the inferior and superior sub-types of anterior hip dislocation, respectively.<ref name="Ken2015" /><ref name=":1" /> [[Hip dysplasia]] also makes one more susceptible to hip dislocation.<ref name=":7">{{Cite web|title=Congenital Hip Dysplasia Symptoms & Treatments {{!}} Orthopedics|url=https://www.hss.edu/condition-list_hip-dysplasia.asp|access-date=2021-03-17|website=Hospital for Special Surgery|language=en}}</ref> Hip dysplasia is a congenital condition in which the hip is deformed in a way that decreases the congruency between the head of the femur and the acetabulum of the pelvis.<ref name=":7" /> Bony congruence is a stabilizing factor to the hip joint, so the decrease in this conferred by hip dysplasia makes one more susceptible to dislocation.<ref name=":7" />

== Diagnosis ==
[[File:Migrationsindex nach Reimers.png|thumb|Reimer's migration index can be used to indicate hip dislocation. The migration index (MI) is normally less than 33%.<ref>{{cite journal | vauthors = Persiani P, Molayem I, Calistri A, Rosi S, Bove M, Villani C | title = Hip subluxation and dislocation in cerebral palsy: outcome of bone surgery in 21 hips | journal = Acta Orthopaedica Belgica | volume = 74 | issue = 5 | pages = 609–14 | date = October 2008 | pmid = 19058693 | url = http://www.actaorthopaedica.be/acta/download/2008-5/06-Persiani%20et%20al.pdf }}</ref>]]
An [[Anatomical terms of location|anterior-posterior]] (AP) X-ray of the pelvis and a cross-table lateral X-ray<ref>{{Cite web|last=Murphy|first=Andrew|title=Hip (horizontal beam lateral view) {{!}} Radiology Reference Article {{!}} Radiopaedia.org|url=https://radiopaedia.org/articles/hip-horizontal-beam-lateral-view-1?lang=us|access-date=2021-03-24|website=Radiopaedia|language=en-US}}</ref> of the effected hip are ordered for diagnosis.<ref name="Ken2015" /><ref name=":1" /><ref name=":0" /> The size of the head of the femur is then compared across both sides of the pelvis. The affected femoral head will appear larger if the dislocation is anterior, and smaller if posterior.<ref name=":4" /> A [[CT scan]] may also be ordered to clarify the fracture pattern.<ref name=":6" />

[[File:Congenitaldislocation10.JPG|thumb|Dislocation of the left hip, secondary to developmental hip dysplasia. Closed arrow marks the [[acetabulum]], open arrow the femoral head.]]

== Management ==
Hip dislocations are a medical emergency, requiring timely placement of the femoral head back into the acetabulum ([[Reduction (orthopedic surgery)|reduction]]) in order to reduce the risk of osteonecrosis of the femoral head.<ref name=":5" /> Most professionals recommend closed reduction (nonoperative) barring operative indications such as irreducible dislocation, delayed presentation, non-concentric reduction, fracture requiring excision and/or [[Open Reduction Internal Fixation|open reduction internal fixation]] (ORIF) among other operative indications.<ref name="Ken2015" /><ref name=":1" /> Prognosis is worsened if reduction is delayed more than 6 hours.<ref name="Ken2015" /><ref name=":1" /> If the reduction is stable, the patient can proceed to protective weight bearing which includes crutch-assisted walking (ambulation) with weight bearing as tolerated for 4–6 weeks succeeding a short period of bed rest.<ref name="Ken2015" /> If reduction is unstable, 4–6 weeks of skeletal traction is necessary before protective weight bearing.<ref name="Ken2015" />

=== Nonoperative ===
The hip should be reduced as quickly as possible to reduce the risk of osteonecrosis of the femoral head.<ref name=Ken2015 /> This is done through manual traction of the thigh inline with the dislocation under general anesthesia and muscle relaxation, or conscious sedation.<ref name="Ken2015" /><ref name=":4" /> Fractures of the femoral head and other loose bodies should be determined prior to reduction. Of note, femoral neck fractures, femoral head fractures, and incarcerated fracture fragments preventing joint reduction are contraindications.<ref>{{cite book |last1=Reichman |first1=Eric F. |title=Chapter 86. Hip Joint Dislocation Reduction |url=https://accessemergencymedicine.mhmedical.com/content.aspx?bookid=683&sectionid=45343727#57709186 |website=Emergency Medicine Procedures |publisher=The McGraw-Hill Companies |date=2013}}</ref><ref name=":1" /><ref>{{Cite journal|last1=Ross|first1=James R.|last2=Gardner|first2=Michael J.|date=2012|title=Femoral head fractures|journal=Current Reviews in Musculoskeletal Medicine|volume=5|issue=3|pages=199–205|doi=10.1007/s12178-012-9129-8|issn=1935-9748|pmc=3535084|pmid=22628176}}</ref> Common closed reduction methods include the Allis method, Stimson Gravity Technique, and the Bigelow maneuvers.<ref name="Ken2015" /><ref>{{Cite book|url=https://archive.org/details/treatiseonfractu00stim|title=A treatise on fractures|last=Stimson|first=Lewis Atterbury | name-list-style = vanc | date=1883|publisher=Philadelphia, H.C. Lea's son & co.|others=The Library of Congress}}</ref> Once reduction is completed, management becomes less urgent and appropriate workup including CT scanning can be completed.<ref name=":4" />

=== Operative ===
Open (surgical) reduction indications include an irreducible dislocation, fracture with fragments preventing congruent reduction, fracture requiring an [[ORIF]], delayed presentation, and non-concentric reduction.<ref name="Ken2015" /><ref name=":1" /> Approaches to surgical reductions include the posterior approach for posterior dislocations ([https://surgeryreference.aofoundation.org/orthopedic-trauma/adult-trauma/acetabulum/approach/kocher-langenbeck-approach-to-the-acetabulum Kocher-Langenbeck]), and the anterior ([[Smith-Petersen anterior approach to the hip|Smith-Petersen]]) approach for anterior dislocations.<ref name="Ken2015" /><ref name=":1" /><ref>{{Cite web|title=Kocher-Langenbeck approach to the acetabulum|url=https://surgeryreference.aofoundation.org/orthopedic-trauma/adult-trauma/acetabulum/approach/kocher-langenbeck-approach-to-the-acetabulum|access-date=2021-04-04|website=site name|language=en}}</ref> A CT scan or Judet views should be obtained prior to transfer to the surgical suite.<ref name=":4" />

===Rehabilitation===
Individuals with hip dislocation should participate in [[physical therapy]] and receive professional prescriptive exercises based on their individual abilities, progress, and overall range of motion. The following are some typical recommended exercises used as rehabilitation for hip dislocation. It is important to understand that each individual has different capabilities that can best be assessed by a physical therapist or medical professional, and that these are simply recommendations.<ref name="bare_url_b">{{EMedicine|article|86930|Hip Dislocation Treatment & Management}}</ref>[[File:weightsforankle.jpg|thumb|A set of ankle weights.]]
[[File:modifiedsideplank.jpg|thumb|Modified side plank.]]

====Exercises====
* Bridge- Lie flat on back. Place arms with palms down beside body. Keep feet hip distance apart and bend knees. Slowly lift hips upward. Hold position for three to five seconds. This helps strengthen the glutes and increase stability of the hip joint.<ref name="bare_url_b" />
* [[Supine]] leg [[abduction (kinesiology)|abduction]]- Lie flat on back. Slowly slide leg away from body and then back in, keeping the knees straight.  This exercises the gluteus medius and helps to maintain stability in the hip while walking.<ref name="bare_url_b" />
* Side Lying Leg [[Abduction (kinesiology)|abduction]]- Lie on one side with one leg on top of the other. Slowly lift the top leg towards the ceiling and then lower it back down slowly.<ref name="bare_url_b" />
* Standing Hip abduction- Standing up and holding on to a nearby surface, slowly lift one leg away from the midline of the body and then lower it back to starting position.  This is simply a more advanced way to do any of the lying hip abduction exercises, and should be done as the person progresses in rehab.<ref name="bare_url_b" />
* Knee raises- While standing and holding onto a chair, slowly lift one leg off the ground and bring it closer to the body while bending the knee. Then lower the leg back down slowly. This helps to strengthen the hip flexor muscles and retain stability in the hip.<ref name="bare_url_b" />
* Hip [[flexion]] and [[extension (kinesiology)|extension]]s- Standing, hold on to a nearby chair or surface. Swing one leg forwards away from you, and hold the position for three to five seconds. Then swing the leg slowly backwards and behind your body. Hold for three to five seconds.  This exercise helps to increase range of motion, as well as strengthening the hip flexor and hip extensor muscles that control much of the hip joint.<ref name="bare_url_b" />
*  Adding ankle weights to any exercises can be done as progress is made in rehabilitation.<ref name="bare_url_b" />

==Prognosis==
Hip dislocations can take anywhere from 2–3 months to fully heal, and even longer depending on associated injuries such as fracture.<ref name=":8" /> Moreover, the outcome ranges from a fully healthy hip to a painful, arthritic one.<ref name="Ken2015" /> With simple posterior dislocations, literature reports great outcomes in 70%-80% of cases.<ref name="Ken2015" /> With complex dislocations, the outcome is often governed by the associated fracture.<ref name="Ken2015" /> Anterior dislocations are noted to have worse outcomes with their higher likelihood of being associated with femoral head injuries.<ref name="Ken2015" /> Those without associated femoral head injuries do better.<ref name="Ken2015" />

Complications of hip dislocation that impact prognosis include post-traumatic arthritis, femoral head osteonecrosis, femoral head fracture, neurovascular injury, and recurrent dislocation.<ref name="Ken2015" /><ref name=":1" /> Post-traumatic arthritis is the most common long-term complication and happens in 20% of hip dislocations, having higher rates among complex dislocations.<ref name="Ken2015" /> Femoral head osteonecrosis happens in 5-40% of dislocations, with rates rising the longer time to reduction (>6 hours).<ref name="Ken2015" /> Similarly increasing in rates with time to reduction, neurovascular injury with most notable being sciatic nerve injury, occurs in 8-20% of cases.<ref name="Ken2015" /><ref name=":1" /> Femoral head fractures accompany 10% of posterior dislocations and 25-75% of anterior dislocations.<ref name=":1" /> Lastly, recurrent dislocations can also occur, however is rare (<2%).<ref name="Ken2015" /><ref name=":1" />

==Epidemiology==
Males are affected more often than females.<ref name="Bla2016" /> Most common cause is high energy trauma such as from a motor vehicle collision or a high-level fall.<ref name="OI2014" /><ref name="Ken2015" /> Traumatic dislocations occur most commonly in those 16 to 40 years old.<ref name="Ken2015" /> Of note, restrained passengers are at a lower risk for a hip dislocation than those unrestrained.<ref name=":1" /> With the hip being inherently stable, dislocations are rare, however have high rates of associated injuries.<ref name="Ken2015" /><ref name=":1" /> For example, half of all hip dislocations are accompanied by a fracture.<ref name="Ken2015" /> Refer to "Prognosis and Complications" section for rates of other associated injuries. The condition was first described in the medical press in the early 1800s.<ref name=":9" /><ref name=":10" />

==Other animals==
{{Main|Dislocation of hip in animals}}

== References ==
<references />

== External links ==
{{Medical resources
|   DiseasesDB     = 3056
|   ICD10          = {{ICD10|S|73|0|s|70}}, {{ICD10|Q|65|0|q|65}}-{{ICD10|Q|65|2|q|65}}
|   ICD9           = {{ICD9|835}}
|   ICDO           =
|   OMIM           = 142700
|   MedlinePlus    =
|   eMedicineSubj  = emerg
|   eMedicineTopic = 144
|   MeshID         = D006618
}}

{{Congenital malformations and deformations of musculoskeletal system}}
{{Dislocations, sprains and strains}}

[[Category:Congenital disorders of musculoskeletal system]]
[[Category:Dislocations, sprains and strains]]
[[Category:Wikipedia medicine articles ready to translate]]