CASE REPORT
TRANSIENT LATERAL SUBLUXATION OF PATELLA :TYPICAL MRI
(3T) FINDINGS
Moon Kanjila, Sudipta Saha, Surajit Das, Samiran Samanta
1
De partm e ntofRadiodiagnos is , Ins titute ofPos t-Graduate Me dicalEducation and Re s e arch and Se th Suk h l
al
K arnani M e m orial(IPGM E& R and SSK M ) H os pital
, Kol
k ata, W e s tBe ngal
, India
PJR April - June 2016; 26(2): 131-133
ABSTRACT
Late ralpate l
l
ofe m orals ubl
uxation is an e ntity w h ich ofte n goe s unre cogniz e d cl
inical
l
y due to its trans ie ntnature .
Patie ntus ual
l
y com pl
ains ofm e dialk ne e pain and is unaw are ofbrie fph as e of dis l
ocation ofpate l
l
a (as itge ts
re duce d s pontane ous l
y). Re curre nt dis l
ocation m ay l
e ad to os te och ondralinjury and os te oarth ritis . M RI h e l
ps
in s pe cific diagnos is of th is condition. W e are pre s e nting a cas e w ith te l
l
tal
e M RI s igns of trans ie nt pate l
l
ar
dis l
ocation.
Introduction
A cas e w ith out any h is tory of pre vious traum a to
k ne e , w h ich s h ow s typicalfe ature s oftrans ie ntl
ate ral
pate l
l
ar s ubl
uxation in M RI (3T) is pre s e nte d h e re .
nos e d due to its trans ie ntnature .1 Patie nts pre s e nt
w ith k ne e s w e l
l
ing and pain in m e dialas pe ctofk ne e .
Cl
inical
l
y it’s ve ry difficul
tto diffe re ntiate itfrom oth e r
s ofttis s ue injurie s , for w h ich M RI fe ature s are ve ry
s pe cific.
Case Presentation
A 26 yrs ol
d m al
e patie ntpre s e nte d w ith righ tm e dial
k ne e pain and s w e l
l
ing fol
l
ow ing a tw is ting injury.
Th e re w as no h is tory ofdire cttraum a to k ne e . Upon
cl
inicals us picion h e unde rw e nt M RI. M RI s can
re ve al
e d m arrow oe de m a in l
ate ralfe m oralcondyl
e
w ith corre s ponding m arrow oe de m a and os te och ondralde fe ctin m e dialface tofpate l
l
a and as s ociate d
jointe ffus ion.
Discussion
Trans ie ntl
ate ralpate l
l
ar s ubl
uxation w ith s pontane ous
re duction is an e ntity w h ich m os tl
y re m ains undiag-
Figure 1: AxialGRE s h ow ing s m al
lfracture ne ar m e dialface t
ofpate l
l
a
Correspondence : Dr. M oon K anjil
al
De partm e ntofRadiol
ogy, (IPGM E& R and
SSK M) H os pital
, K ol
k ata 700020,
W e s tBe ngal
, India.
Mobil
e : + 9 17059 716120
Em ail
: k anjil
al
m oon@ gm ail
.com
Subm itte d 9 Augus t2015, Acce pte d 9 O ctobe r 2015
PA K I S TA N J O U R N A L O F R A D I O LO G Y
PJR April - June 2016; 26(2)
131
Figure 2: AxialT2FS s h ow ing bone bruis e in m e dialface tof
pate l
l
a and l
ate ralcondyl
e offe m ur
Figure 4: SAG T2FS re form ate d im age s h ow ing bone bruis e in
m e dialface tofpate l
l
a
Figure 3: SAG T2FS re form ate d im age s h ow ing bone bruis e in
l
ate ralcondyl
e offe m ur
It’s s e e n m ore com m onl
y w ith l
ate raltroch l
e ar dys pl
as ia, pate l
l
a al
ta and l
ate ral
iz ation oftibialtube ros ity.2
Us ual
l
y it’s s e e n in young active adul
ts fol
l
ow ing a
tw is ting injury in a s e m i fl
e xe d (30 de gre e ) k ne e . Th e
fe m ur inte rnal
l
y rotate s ove r a fixe d tibia caus ing pate l
l
a to s ubl
uxate l
ate ral
l
y cau s ing bruis e both in
PA K I S TA N J O U R N A L O F R A D I O LO G Y
m e dialpate l
l
ar face t and l
ate ralfe m oralcondyl
e
w ith as s ociate d inju ry to m e dialre tinacu l
u m of
pate l
l
a.W h e n k ne e is e xte nde d s pontane ou s
re duction ofpate l
l
ar dis l
ocation occurs and during
th is ph as e m e dialpate l
l
ar im paction agains t th e
non- w e igh tbe aring ante rol
ate ralas pe ct of th e
l
ate ralfe m oralcondyl
e produ ce s ch aracte ris tic
bone bruis e .
Sk yl
ine vie w of conve ntionalradiograph m ay s h ow
dis l
ocate d pate l
l
a and jointe ffus ion;h ow e ve r M RI is
th e onl
y accurate diagnos tic m odal
ity for th is con3
dition. Axialand coronalT2FS s h ow s bone bruis e
in l
ate ralfe m oralcondyl
e (w h ich is s ituate d m ore
s upe riorl
y and l
ate ral
l
y th an m arrow e de m a ofante rior
cruciate l
igam e nt [ACL] te ar) and m e dialface t of
pate l
l
a w ith joint e ffus ion. AxialGRE re ve al
s as s ociate d os te och ondralinjury to pate l
l
a. Me dialpate l
l
ar
re tinacul
um m ay s h ow ch ange s from m il
d s prain to
com pl
e te te ar.4
If goe s undiagnos e d trans ie nt pate l
l
ar s ubl
uxation
can l
e ad to l
ong te rm dis abil
ity in th e form ofos te od be
arth ritis and ch ronic k ne e pain. 5 M RI s h oul
advis e d for prope r de l
ine ation of s oft tis s ue injury
and os te och ondralde fe cts .6
Aknowledgement:
W e h ave no pe rs onalor financialinte re s t in w riting
th is re port. It’s pure l
y for acade m ic purpos e .
PJR April - June 2016; 26(2)
132
References
1. Fith ian D C, Paxton E W , S tone M L, e t al
..
Epide m iol
ogy and naturalh is tory ofacute pate l
l
ar
dis l
ocation. Am J Sports M e d 2004;32(5): 111421. Cros s Re f, M e dl
ine
l
anpää P, M attil
aVM , Iivone n T, Vis uri T,
2. S il
Pih l
ajam äk i H . Incide nce and ris k factors ofacute
traum atic prim ary pate l
l
ar dis l
ocation. M e d Sci
S ports E xe rc 2008; 40(4): 606- 11. Cros s Re f,
M Bal
dw in JL. Th e anatom y of th e m e dialpate l
l
ofe m orall
igam e nt.Am J Sports M e d 2009 37:
2355-62.
3. Dirim B, H agh igh i P, Trude l
lD e tal
. M e dialpate l
l
ofe m orall
igam e nt: cadave ric inve s tigation of
anatom y w ith M RI, MR arth rograph y, and h is tol
ogic
corre l
ation. AJR 2008: 191: 49 0-8.
4. Sande rs TG, M orris on W B, Singl
e ton BA, M il
l
er
M D, Cornum K G. M e dialpate l
l
ofe m orall
igam e nt
injury fol
l
ow ing acute trans ie ntdis l
ocation ofth e
pate l
l
a: M R findings w ith s urgicalcorre l
ation in
14 patie nts . J Com put As s is t Tom ogr 2001;25:
9 57-62.
. Trans ie nt
5. Earh art C, Pate lDB, W h ite EA e t-al
l
ate ralpate l
l
ar dis l
ocation: re vie w of im aging
findings , pate l
l
ofe m oralanatom y, and tre atm e nt
options . E m e rg Radiol
. 2012; doi: 10. 1007/s
10140-012-1073-9 - Pubm e d citation
6. Atk inDM , Fith ian DC, M arangi K S, Stone M L,
Dobs on BE, M e nde l
s oh n C. Ch aracte ris tics of
patie nts w ith prim ary acute l
ate ralpate l
l
ar dis l
ocation and th e ir re cove ry w ith in th e firs t6 m onth s
of injury. Am J Sports M e d 2000;28(4): 472-9 .
M e dl
ine
PA K I S TA N J O U R N A L O F R A D I O LO G Y
PJR April - June 2016; 26(2)
133