日 小整会誌 (J Jpn Ped Orthop Ass) 18 (2) : 357-360， 2009

Recurrent Patellar Dislocation with Chondral Inj ury :O ur Experience with Distal Realignment andAutologous Chondrocyte Implantation
Dr. Andrew K. S. Lim ( MBBS， MRCSEd， M. Med)
Department o f Orthopaedic Surg巴ry， National Univ巴rsity Hospital. Singapor巴Dr. J ames H. P. H ui ( MBBS， FRCSEd， F AMS)
Department o f Orthopaedic Surgery， National Univ巴rsity Hospital. Singapore

Abstract : The surgical management of recurr巴nt traumatic patellar dislocation includes
proximal and distal realignment proc巴dures. A subset of patients would present with associatedchondral injury. There has been recent interest in the treatment of cartilag巴 injuries to reduce
patients' symptoms and to avoid the appearance of futur巴 secondary arthrosis. The choice of
optimal treatment technique in this group of patients remains uncl巴ar
We evaluate our case series of 12 young patients who underwent autologous chondrocyte
implantation (ACI) with a distal r巴alignment procedure for significant chondral injury and patellar
maltracking. Pre and postoperative functional assessments wer巴 made using the IKDC， Lysholmand Tegner scores. Our results show a significant improvement of outcome.
Further studies with ACI comparing distal and proximal realignment would perhaps bett巴r
defin巴 the optimal treatment options for this cohort of patients

Introduction
Traumatic patellar dislocations a丘ect mainly

Mat巴rials and Methods
Between J an uary

2004

and J une

2007.

all

adolescent and young adults. To reduce the risk

patients who had a history of traumatic patellarof osteoarthritis secondary to articular Il1Jury

dislocation wer巴 referr巴d to th巴 orthopaedic

caused by recurrent dislocations as well as toclinic. These patients would hav巴 initial X-rays toencourage normal development of the patellofe­

rul巴 out an osteochondral fragm巴nt. Following a 6

moral joint， surgical stabilization of the patellar

to 9-month trial of physical therapy. patients whoand repair of any chondral inj ury is important inthis age group 8J

continued to experience recurrent symptoms ofinstability or pain. underwent further evaluation.
This included a CT scan of the knee from 0 to 30

Key wOl'ds : patellar dislocation， reaJignment. chondrocyte implantation
Add l'ess : Department of Orthopaedic Surgery， National University Hospital

5 Lower Kent Ridge Road， Singapore

1 19074
Tel : + 65 6779 5555
Fax : + 65 6778 0720
E-mail : Andrew_KS_Lim@nuh.com.sg
357

degrees f1exion to assess pat巴Jlar tracking as wellResults

as a MR1 to assess the presence of chondral
IDJ ury

From January 2004 to J une 2007， a total of 1 2

Patients with evidence of patellar subluxation

pati巴nts underwent surgery for distal patellar(patellofemoral congruence angle + 5 degrees orrealignment with ACI. The Roux Goldthwaitgreater) 5) and significant chondral inj ury ( Qut巴r

procedure was performe d for 5 patients while 7

bridge 1V， more than 1 cm2) were offered distal

patI巴nts underwent 出e Elmsli巴一Trillat proce­

realignment and AC1 as a 2-stage proc巴dure.

dure

The first stage was performed arthroscopically toThe mean age of the pati巴nts was 16 . 0 years

assess and debride the chondral lesion followed(range 12 to 19) with 8 mal巴s and 4 females. Theby harvesting of cartilage from the non-weightmean duration of symptoms preop巴ratively wasbearing region of the superomedial f巴moral

7 . 2 months whil巴 th巴 mean postoperative follow­

condyl巴. The second stage a month later involved

up d uration was 17 . 5 months (range 1 2 to 24) ーan arthrotomy and implantation of c ulture

Qne patient reported transient paresthesia

expand巴d autologous chondrocytes b巴neath aover the wound site. There was also a case of pain

sutured and fibrin glue-sealed periosteal patch

over the screw site and extensor lag secondary totaken from the proximal tibia. The distal realign­

quadriceps dysfunction. Ther巴 was no postopera­

ment procedure was then performed. For ative infection， osteotomy non-union， patellar

skeletally mature patient. the Elmslie-Trillat

tendon rupture or patellar dislocation.

procedure was performed， in which th巴 tibial

Mean pre and postoperative 1KDC， Lysholm

tu b巴rosity wastransposed medially by 1 cm andand Tegner scores w巴re compared for statistical

held by a single screw. 1n a patient with an open

significance with th巴 Wilcoxon Matched-Pairs

physis， the Roux Goldthwait procedure wasSigned-Ranks Test (Table 1 )performed， in which the lateral half of the pat巴lIar
tendon was transposed medially. Patellar track­ing was visually assessed.

Discussion
There are numerous surgical procedures for

Following surgery， patients underwent rehabilrecurrent patellar dislocation which aim toitation therapy in a ranger knee brace for 6

correct malalignment. These rang巴 from release

weeks with partial weight bearing. Postoperative­of the lateral retinaculum of the pat巴Ilar to medial

Iy， th巴y were reviewed in the clinic for functional

displacement of th巴 patellar tendon or tibial

1nternational Knee Documentation Committee

tuberosity.1) Up to 22% of skeletally immature(1KDC) ， Lysholm and T巴gner score assessments

pati巴nts require surgery for recurr巴nt disloca­

at 3 monthly intervals for a minimum follow-up

tions after an initial patellar dislocation， whilep巴riod of 12 months.6)7) 1I) Mean pre and postoper­

33 % can have instability lO) Non-resolution ofativ巴 functional scores were calculated andsymptoms following patellar surgery may be dueanalyzed for statistical significance using th巴

to non-recognition of articular compromise.

Wilcoxon Matched-Pairs Signed-Ranks Test

The initial r巴sults of patellar lesions treatedwith AC1 w巴re disappointing2) 1mpr‘oved techni・ques， which included more radical debridement of358

Table 1 .

Comparison of pre and postoperative functional scores

Functional Scoring System

Mean Preoperative Score(95% C. 1.)

Mean Postoperative Score(95% C. 1.)

Statistical Significance

IKDC

40 . 7 (30 4-50 2)

65 9 (50 7-80 1 )p < = 0 . 002

Lysholm

42 . 0 (29 . 0-53 0)

53 3 (43 . 4-70 7)

p < = 0 . 003

Tegn巴r

1 55 (0 55-2 20)

3 55 (2 10-4 . 55 )p < = 0 . 008

IKDC : International Knee Documentation Committee

tissue around the defect and attention to correct­

tional scores post-operatively . How巴ver， this 2-ing patellofemoral maltracking， have resulted instage procedure is not without the morbidity ofgood to excellent outcomes 9)

an arthrotomy which c a n require a more

The aim of a distal realignm巴nt procedure

protracted period of recovery .

would be to alter and improve Q-angle . However，

Further obj巴ctive assessment can be per­the Q-angle can be measured to be falsely normal

formed postoperatively either by arthroscopic

should the patellar be in a sublux巴d position.

evaluation or using MRI. 1n particular， postHence， we utilized the patellofemoral congruencechondrocyte implantation evaluation of the graft­angle instead as a measure of patellar subluxation

ed area can be performed via artlu命oscopy uSll1gfor malalignment.

the 1nternational Cartilage Repair Society (1CRS)The Haus巴r technique introduced in 1 938 was

visual cartilage repair assessment . 1n addition，

the initial standard procedure for the treatment

MR1 evaluation can be performed to assess graftof recurrent patellar dislocation . 1n this proce­

fill， surface in巴gularity and signal as w巴11 as

dure， the tibial tubercle was moved distally andmedially， however， resulting osteo arthritic

subchondral bone marrow oedema and effusion of
the immediate area around the repair .'1 )changes in the patellofemoral joint were reported

As the n umber of p atients in this series was

On the contrary， the Elmslie-Trillat procedur巴small and the follow-up d uration was relatively

introduc巴d in 1 964， which involved moving theshort， a larger number of patients with a longer

tibial tubercle only medially， showed 1巴ss osteoar­

follow-up period are needed to further validate

thritic changes in the patellofemoral joint with

our findings. Nevertheless， our short-term re­good to excellent clinical outcome in more than
80 % of knees .3)

sults provide evidence that correction of patellar

1n the immature skeleton， bony realignment

with AC1 is e妊巴ctive and provides good function­

procedures would be contraindicated due topossible premature fusion of the anterior tibial
physis resulting in a genu recurvatum . 1n thismaltracking and treatment of subchondral lesions
al outcome for our young patients .

Conclusiongroup of patients， medial transposition of theThe management of recurrent traumaticlateral half of the patellar tendon using the Roux

patellar dislocation includes surgical stabilization .

Goldthwait procedure would be more appropri­

Patients with significant patellar malalignment

ateand chondral 111] ury can benefit from a distal

We b elieve that p atients with significant

realignment with AC1 procedure. Further studies

patellar malalignment and chondral injury would

involving the use of proximal realignment may

benefit from a distal realignment and AC1

provide a clearer comparison and indication ofprocedure . Our results indicate improved func

other tr巴atment options.
359

References
1 ) Bensahel H， Souch巴t P， Pennecot GF et al. The
unstable pate11ar in children. J P巴diatr Orthop
B 9 (4) : 265-270， 20002) Brittberg M. Lindahl A， Nilsson A 巴t al
Treatment of deep cartilage defects in the kneewith autologous chondrocyte transplantation
N Engl J Med 331 ( 14) : 889-895， 1994
3) Brown DE， Alexander AH， Lichtman DM. The
Elmslie-Tri11at procedure : evaluation in patel
lar dislocation and sutヲluxation. Am J Sports
Med 1 2 (2) : 104-109， 1984.
4) Henderson I， Gui J， Lavigne P. Autologous
chondrocyte implantation : natural history of
postimplantation periosteal hypertrophy ande妊巴cts of repair-site debridement on outcome.
Arthroscopy 22 ( 12) : 1 318-1324， 2006
5) Inoue M， Shino K， Hirose H et al. Subluxation of
the pat巴11a. Computed tomography analysis ofpate11ofemoral congru巴nce. J Bone J oint Surg
Am 70 (9) : 1331-1337， 1988
6) 1rrgang JJ， Anderson AF， Boland AL， et a1.
Dev巴lopment and validation of th巴 lJ1terna tIon-360

al lm巴巴 documentation committee subj巴ctlve
kne巴 form. Am J Sports Med 29 : 600-613，2001
7) Lysholm J， Gi11quist ]. Evaluation of knee
ligament surgery results with special emphasis
on use of a scoring scale. Am J Sports Med 10(3) : 150-154， 1 9828) Macnicol MF， Turn巴r MS. The kn巴e. 1n :B巴nson MKD， Fixsen J A， Macnicol MF， eds.
Children's Orthopaedics & Fractures. Edinburgh : Churchi11 Livingstone， 1994 : 471-486
9) Peterson L， Minas T， Brittberg M et al. Two-to
9-year outcome after autologous chondrocytetransplantation of the knee. Clin Orthop 374 :
212-234， 2000.
10) Stanitski C1. Articular hypermobility andchondral injury in patients with acute pate11ar
dislocation. Am J Sports Med 23 (2) : 146-150，
1995.
1 1 ) Tegn巴r Y， Lysholm ]. Rating syst巴ms in th巴
evaluation of kne巴 ligament inj uri巴s. Clin
Orthop Relat R巴s 1 98 : 43-49， 1985