“Joint locking (medicine)”的意思、由来-开放百科全书

In medicine, joint locking is a symptom of pathology in a joint. It is a complaint by a person when he is unable to fully flex or fully extend a joint. This term is also used to describe the mechanism of lower limb joints held in full extension without much muscular effort when a person is standing.

Clinical symptom

Complaint of locking sensation in the knee joint can be divided into true locking and pseudolocking. True locking happens when the intra-articular structure (e.g. ligaments)^[1] is damaged, or there is the presence of loose body inside the joint, or there is a meniscal tear. The knee can be unlocked by rotating the leg and full movement can be restored. A person may felt the presence of loose body in the suprapatellar region, or lateral and medial gutter. Once the loose bodies is felt, it would slide and move to other area, thus it is also termed as "joint mouse".^[2]

Pseudolocking usually happens when a person feels pain when trying to flex or extend a knee joint while there is no structural causes of the locking. The locking is usually relieved after massage or taking painkillers.^[2]

Locking mechanism

Locking of the knee happens during the last stages of extension when a person is standing up. Medial rotation of femur occurs as the space available at the lateral condyle of tibia is being used up by the lateral condyle of femur during extension. Therefore, lateral femoral condyle acted as an axis for medial femoral condyle to rotate backwards. This movement is aided by oblique pull of the ligaments of the knee joint and contraction of the quadriceps muscles. The ligaments are pulled taut when the knee joint is locked in place during standing. When the knee is flexed, it is unlocked by the popliteus muscle through the lateral rotation of femur.^[4]

The locking mechanisms of hip joint^[5] and midtarsal joint^[6]^[7] are also being investigated in cadavers.

References

1. ^¹{{cite book|last1=Roald|first1=Bahr|last2=Sverre|first2=Mæhlum|title=Clinical Guide to Sports Injuries|date=2004|publisher=Human Kinetics|isbn=9780736041171|page=325|url=https://books.google.com.my/books?id=mmRnr0x0p4QC&pg=PA325|accessdate=19 January 2018}}
2. ^¹²{{cite book|last1=Nick|first1=Harris|title=Advanced Examination Techniques in Orthopaedics|date=2003|publisher=Cambridge University Press|isbn=9781841100739|page=150|url=https://books.google.com.my/books?id=OajuJGXR25gC&pg=PA150|accessdate=19 January 2018}}
3. ^{{cite journal|vauthors=Hixon AL, Gibbs LM |title=What Should I Know About Osteochondritis Dissecans?|journal=American Family Physician|volume=61|issue=1|pages=158|date=January 2000|url=http://www.aafp.org/afp/20000101/20000101d.html}}
4. ^{{cite book|last1=Krishna|first1=Garg|title=BD Chaurasia's Human Anatomy (Regional and Applied Dissection and Clinical) Volume 2 - Lower limb, abdomen, and pelvis|date=2010|publisher=CBS Publishers and Distributors Pvt Ltd|location=India|isbn=978-81-239-1864-8|page=156|edition=Fifth|chapter=12 - Joints of lower limb|quote=Locking is a mechanism that allows the knee to remain the position of full extension as in standing without much muscular effort}}
5. ^{{cite journal|last1=W.H|first1=Roberts|title=The locking mechanism of the hip joint|journal=The Anatomical Record|date=November 1963|volume=147|issue=3|pages=321–324|doi=10.1002/ar.1091470303}}
6. ^{{cite journal|last1=Blackwood|first1=CB|last2=Yuen|first2=TJ|last3=Sangeorzan|first3=BJ|last4=Leodux|first4=WR|title=The midtarsal joint locking mechanism|journal=Foot & Ankle International|date=December 2005|volume=26|issue=12|pages=1074–1080|doi=10.1177/107110070502601213|pmid=16390642}}
7. ^{{cite journal|last1=Okita|first1=N|last2=Meyers|first2=SA|last3=Challis|first3=JH|last4=Sharkey|first4=NA|title=Midtarsal joint locking: new perspectives on an old paradigm|journal=Journal of Orthopaedic Research|date=January 2014|volume=32|issue=1|doi=10.1002/jor.22477|pmid=24038197}}