Pathology Lateral hypermobility of the patella Dysplastic
distal one third of VMO High or lateral position of the patella
Previous history of patellar subluxation
Slide 9
Patellar dislocations Rare in a child. Common in adolescents.
Twisting injury or direct trauma Lateral Acute vs recurrent
Osteochondral fractures of patella or femur
Slide 10
Patellofemoral Instability Assessment History Acute or
spontaneous Duration Number of episodes Circumstances of injury
Previous treatment Beware ACL injury (Pop) Syndromes
Slide 11
Patellofemoral Instability Assessment Examination Full knee
examination Patella Tracking J-sign Medial or lateral tenderness
Tilt or lateral tightness Apprehension Test (most reliable) Q-angle
Torsional profile General Laxity
Radiological measurements Tibial tubercle trochlear groove
distance Lateralisation of the patella Abnormal when above 20
mm
Slide 17
Patellofemoral Instability Conservative Treatment: RICE SLR/
Isometric Quadriceps Open and closed chain kinetic exercises
Gradual return to activities No casts or immobilization Patellar
stabilizing orthosis Time
Slide 18
Patellofemoral Instability ? Role for acute surgery Treatment:
No place for acute operative stabilization in children and
adolescents Acute patellar dislocation in children and adolescents.
Surgical technique. J Bone Joint Surg Am. 2009 ; 91: 139-45.
Nietosvaara Y, Paukku R, Palmu S, Donell ST. The slaying of a
beautiful hypothesis by an ugly fact T H Huxley
Slide 19
Acute patellar dislocation in children and adolescents: a RCT.
J Bone Joint Surg (Am) 2008;90(3):463-470 62 patients younger than
16 who sustained acute patellar dislocation with an osteochondral
fragment of 15mm. 36 0peratively 28 non-operatively: 1. 7 only
lateral release 2. 29 repair medial structures
Slide 20
Acute patellar dislocation in children and adolescents: a RCT.
J Bone Joint Surg (Am) 2008;90(3):463-470 14 year follow up Initial
operative repair did not improve the long-term outcome. 70 %
re-dislocation rates Positive family history was a significant risk
factor for recurrence
Slide 21
Acute patellar dilsocation in adlescents: operative versus non-
operative treatment. Int orthopaedics. Apostolovic
2011;35(10):1483-1487. Non randomised prospective study- 37
adolescent knees Decision for surgery on the basis of clinical and
arthroscopic findings. Not clear No difference between operative
and non-operative treatment in terms of re-dislocation rates and
functional outcome
Slide 22
Surgical intervention Recurrent instability with functional
compromise Osteochondral lesions. Repair if > 2cm
A Surgical algorithm for the treatment of patellar dislocation.
Results of 5 year follow up. Acta Orthop Belgica 2013.
Slide 26
Higher re-dislocation rates in immature patients who underwent
proximal re-alignment procedures. Mature patients with combined
proximal and distal procedures had the lowest re-dislocation rates
but low functional scores.
Slide 27
Predictors of recurrent instability after acute patellofemoral
dislocation in paediatric and adolescent patients. Am J Sports Med
2013;41(3):575-581. USA. 222 knees Mean age 14.9 years Patients
with open physes and dysplastic trochlea had the highest
dislocation rate at 69% Age, sex, body mass index and patella alta
were not associated with recurrent instability
Slide 28
Outcomes after patellar re-alignment surgery for recurrent
patellar instability dislocations: a minimum 3-year follow-up study
of children and adolescents. JPO 2011;31(1):65-71. USA Recurrent
dislocation 7% Subjective opinion of knee function was less than
expected 5 years post-op.
Slide 29
Weight-bearing osteochondral lesions of the lateral femoral
condyle following patellar dislocation in adolescents athletes.
Orthopaedics 2012;35(7):1033- 1037. USA 80 patients with acute
patellar dislocation 27.5% had an osteochondral lesion of the wt
bearing area of lateral femoral condyle and 60% required surgical
intervention Suggestion of performing an MRI if there is tenderness
over the lateral femoral condyle.
Slide 30
Surgical treatment for instability - Summary Do not operate
acutely Understand and try to correct your anatomy No tibial
tubercle transfer in skeletally immature patients
Slide 31
Congenital patella dislocation First described by Singer 1856
Present at birth diagnosed then or within first decade The patella
should be permanently fixed to the lateral aspect of the femur
Slide 32
Congenital patella dislocation Aetiology Failure of the myotome
containing the Quadriceps and Patella from internally rotating in
the first trimester
Slide 33
Congenital patella dislocation Pathology Extensor mechanism
inserted antero-laterally Contracture of Iliotibial band, Vastus
lateralis, and Lateral capsule Loose and atrophic medial capsule
& VMO Hypoplastic femoral trochlea External rotation of tibia
and valgus deformity of knee
Slide 34
Congenital patella dislocation Treatment Initiated before 1 st
birthday Extensive lateral release of whole of Vastus lateralis
& knee capsule Extensor mechanism is reduced and medial
structures lateralised +/- Roux Goldthwaite
