Scientific Articles   |    
Patellar Subluxation at Terminal Knee Extension: Isolated Deficiency of the Medial Patellomeniscal Ligament
William P. Garth, Jr., MD1; Geoffrey S. Connor, MD2; Lydia Futch, MSPT, ATC1; Heloise Belarmino, MAE, ATC, LAT1
1 UAB Sports Medicine Clinic, 1600 7th Avenue South, Suite 402, Birmingham, AL 35233. E-mail address for W.P. Garth Jr.: William.garth@ortho.uab.edu
2 Alabama Orthopedic & Spine Center, 52 Medical Park East Drive, Suite 115, Birmingham, AL 35235
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Investigation performed at the University of Alabama at Birmingham, Birmingham, Alabama

Disclosure: The authors did not receive any outside funding or grants in support of their research for or preparation of this work. Neither they nor a member of their immediate families received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity.

Copyright © 2011 by The Journal of Bone and Joint Surgery, Inc.
J Bone Joint Surg Am, 2011 May 18;93(10):954-962. doi: 10.2106/JBJS.H.00103
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The medial patellomeniscal ligament has been determined in vitro to be the only substantial distal-medial restraint to lateral patellar displacement. The purpose of this study of prospectively collected data was to determine if isolated deficiency of the medial patellomeniscal ligament, resulting in excessive lateral patellar translation and associated symptoms, could be identified. We hypothesized that, if symptoms were associated with isolated deficiency of that ligament, the laxity and symptoms should resolve after plication of that ligament alone.


Testing for lateral patellar displacement in the extended knee by exertion of force through the distal patellar attachment of the medial patellomeniscal ligament was performed on 745 patients with patellofemoral syndromes during a twenty-eight-month period. In addition, the ability to recognize pathologically increased lateral patellar translation preoperatively with use of such testing was compared with the ability to recognize increased lateral translation with testing in 439 patients undergoing arthroscopy under anesthesia during that period for any reason. Preoperative symptoms and impairment in knees with isolated deficiency of the medial patellomeniscal ligament were documented and compared with the postoperative results.


Isolated medial patellomeniscal ligament deficiency was identified with testing under anesthesia in twenty-three of the 439 knees undergoing arthroscopy for any reason, and twenty of those twenty-three cases had been detected preoperatively with use of lateral patellar displacement testing. Isolated medial patellomeniscal ligament plication was performed in these twenty-three cases, and follow-up data at a mean of 30.8 months were available for twenty-one of the cases. The mean International Knee Documentation Committee subjective score increased from 38.9 preoperatively to 84.6 postoperatively, and recurrent symptomatic pathological lateral patellar translation was present in only one patient.


Isolated deficiency of the medial patellomeniscal ligament can be detected by physical examination. Restoration of the normal length of the ligament by plication can lead to resolution of detectable patellar subluxation and its associated symptoms.

Level of Evidence: 

Diagnostic Level IV. See Instructions to Authors for a complete description of levels of evidence.

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    These activities have been planned and implemented in accordance with the Essential Areas and policies of the Accreditation Council for Continuing Medical Education (ACCME) through the joint sponsorship of the American Academy of Orthopaedic Surgeons and The Journal of Bone and Joint Surgery, Inc. The American Academy of Orthopaedic Surgeons is accredited by the ACCME to provide continuing medical education for physicians.
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