Purpose
The primary study objective was to describe the incidence of osteochondral damage
(OD) in our cohort of patients with patellar instability (PI). The secondary objective
was to assess for associations between patient demographic characteristics, duration
of PI, and quantitative radiographic measurements of anatomic risk factors for PI
and OD in this cohort.
Methods
A retrospective chart review identified patients treated for PI at a tertiary referral
center between 2013 and 2018. Patients were evaluated for osteochondral injury with
either magnetic resonance imaging if treated nonoperatively or operative reports if
treated surgically. The Caton-Deschamps ratio, proximal tibial tubercle–to–trochlear
groove (pTT-TG) distance, distal tibial tubercle–to–trochlear groove (dTT-TG) distance,
lateral trochlear inclination (LTI) angle, lateral patellar inclination (LPI) angle,
and sulcus angle were calculated from magnetic resonance imaging scans. Trochlear
dysplasia is an important risk factor for PI that can be reliability quantified by
the pTT-TG distance, dTT-TG distance, LTI angle, sulcus angle, and LPI angle. Demographic
data including age at first instability event, sex, body mass index, symptom duration,
and number of dislocations were documented.
Results
A total of 125 knees in 118 patients (average age, 13.9 ± 3.4 years; 48% female patients)
with PI were identified. Within this cohort, 67% were treated surgically and 53% had
OD. No association was identified between osteochondral injury and age, sex, body
mass index, symptom duration, LTI angle, LPI angle, dTT-TG distance, pTT-TG distance,
or number of dislocations. An increased sulcus angle (more dysplasia) showed a statistically
significant association with osteochondral pathology (P = .021), and higher sulcus angles were statistically significantly associated with
acute osteochondral fracture compared with chondral injury (P = .001).
Conclusions
Using quantitative analysis of trochlear dysplasia, this study identified a significant
association between trochlear dysplasia (sulcus angle) and the incidence of OD in
our cohort of patients with PI. The frequency of dislocation or subluxation and patient
demographic characteristics were not significantly associated with OD.
Level of Evidence
Level III, retrospective prognostic study.
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Article info
Publication history
Published online: May 04, 2021
Accepted:
April 23,
2021
Received:
December 16,
2020
See commentary on page 3477Footnotes
The authors report no conflicts of interest in the authorship and publication of this article. Full ICMJE author disclosure forms are available for this article online, as supplementary material.
Identification
Copyright
© 2021 by the Arthroscopy Association of North America
