Purpose
To (1) determine the effect of severe patella alta on lateral patellar displacement
after medial patellofemoral ligament (MPFL) reconstruction and medial quadriceps tendon–femoral
ligament (MQTFL) reconstruction and (2) determine whether lateral displacement significantly
differs between MPFL and MQTFL reconstructions in the setting of severe patella alta
(Caton-Deschamps Index [CDI] of 1.6).
Methods
Eight cadaveric specimens were included. High–tensile strength suture was used to
create a model of adjustable patellar height. Patellar height was set using fluoroscopy
to CDI ratios of 1.0 (normal) and 1.6 (alta). Specimens underwent testing (1) with
MPFL reconstruction, (2) with MQTFL reconstruction, and (3) in a medial patellofemoral
complex (MPFC)–deficient control state, in randomized order, at both CDI settings:
1.0 and 1.6. Lateral patellar translation was measured at 0°, 10°, 20°, 30°, 45°,
60°, and 90° of knee flexion with 10 N of laterally directed load.
Results
At a CDI of 1.6, MPFL reconstruction showed significantly lower lateral displacement
than MQTFL reconstruction at 0° and 20°. When compared with MPFC-deficient controls
at a CDI of 1.6, MPFL reconstruction showed significantly lower displacement at 0°
and 20° whereas MQTFL reconstruction was not significantly different at any degree
of flexion.
Conclusions
In the setting of severe patella alta (CDI of 1.6), MPFL reconstruction results in
less lateral patellar displacement than MQTFL reconstruction at 0° and 20° of knee
flexion. At higher flexion angles (≥30°), there is no difference between the 2 reconstruction
techniques and the CDI no longer has an effect. At a CDI of 1.0, MPFL reconstruction
shows lower displacement than MQTFL reconstruction in full extension only. Surgeons
performing MPFC reconstruction should evaluate patients for patella alta and consider
patellar height when deciding on the reconstruction technique.
Clinical Relevance
This study suggests that MQTFL reconstruction may be less stable than MPFL reconstruction
in the setting of patella alta, without other known pathoanatomic factors, at early
knee flexion angles. Patellar height should be considered when choosing the appropriate
reconstruction technique in the absence of a distalization procedure.
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Article info
Publication history
Published online: February 11, 2022
Accepted:
January 30,
2022
Received:
September 29,
2021
Footnotes
The authors report the following potential conflicts of interest or sources of funding: A.B.Y. receives personal fees from ConMed Linvatec, JRF Ortho, and Olympus; receives grants from Organogenesis, Vericel, and Arthrex; receives nonfinancial support from Patient IQ, Smith & Nephew, and Sparta Biomedical; and owns stock or stock options in Patient IQ, outside the submitted work. Full ICMJE author disclosure forms are available for this article online, as supplementary material.
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© 2022 Published by Elsevier on behalf of the Arthroscopy Association of North America
