MRI Diagnosis of Patellar Clunk Syndrome Following Total Knee Arthroplasty

Thomas J. Heyse, MD
Department of Orthopedics and Rheumatology, University Hospital Marburg, Baldingerstrasse, Germany

Le Roy Chong, MD
Hospital for Special Surgery, New York

Jack Davis, MSN, RN, ONC
Hospital for Special Surgery, New York


Steven B. Haas, MD

Chief of Knee Service, Hospital for Special Surgery
John N. Insall Chair, Knee Surgery
Attending Orthopedic Surgeon, Hospital for Special Surgery
Professor of Orthopaedic Surgery, Weill Cornell Medical College

Mark P. Figgie, MD

Chief of the Surgical Arthritis Service, Hospital for Special Surgery
Associate Attending Orthopaedic Surgeon, Hospital for Special Surgery
Associate Professor of Orthopaedic Surgery, Weill Cornell Medical College

Hollis G. Potter, MD

Chairman, Division of Magnetic Resonance Imaging
Attending Radiologist, Hospital for Special Surgery
Professor of Radiology, Weill College of Medicine of Cornell University

Abstract

Background

Patellar Clunk Syndrome is a painful condition associated with a mechanical catching or clunking during active extension following total knee arthroplasty (TKA). The syndrome is caused by growth of interposing soft tissue usually at the superior pole of the patella. This interposed soft tissue cannot be visualized on plain radiographs.

Questions

The aim was to ascertain if magnetic resonance imaging (MRI) would prove helpful in confirming the clinical diagnosis of patellar clunk by visualizing the interposed soft tissues adjacent to the patella and that the recognition of this tissue would be highly reproducible.

Methods

MRI scans of 12 patients with clinical suspicion or related symptoms of a patellar clunk syndrome following primary TKA were retrospectively evaluated. Size of soft tissue masses proximal to the patella were determined in sagittal and axial MRI views. Largest diameters were recorded in two dimensions by two independent observers, and interobserver reliability was determined by intra-class correlation coefficients (ICC).

Results

Nine patients (75%) showed obvious MRI findings consistent with a patellar clunk lesion with high interobserver reliability (ICC values >0.75). In eight patients, this lead to operative treatment with arthroscopic debridement.

Discussion

MRI helps confirm the clinical diagnosis of patellar clunk. The data indicate that MRI is effective in defining the soft tissue lesion that is implicated in clinically evident patellar clunk syndrome after TKA.

This article appears in HSS Journal: Volume 8, Number 2.
View the full article at springerlink.com.

About the HSS Journal

HSS Journal, an academic peer-reviewed journal published three times a year, February, July and October. The Journal accepts and publishes peer reviewed articles from around the world that contribute to the advancement of the knowledge of musculoskeletal diseases and disorders.


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