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The Modified Dunn Procedure for Unstable Slipped Capital Femoral EpiphysisA Multicenter Perspective
Wudbhav N. Sankar, MD1; Kelly L. Vanderhave, MD2; Travis Matheney, MD3; José A. Herrera-Soto, MD4; Judson W. Karlen, MD5
1 Division of Orthopaedic Surgery, The Children’s Hospital of Philadelphia, 2nd Floor Wood Building, 34th and Civic Center Boulevard, Philadelphia, PA 19104. E-mail address: sankarw@email.chop.edu
2 C.S. Mott Children’s Hospital, University of Michigan, 1540 Medical Center Drive, Ann Arbor, MI 48109
3 Department of Orthopaedic Surgery, Hunnewell 2, Boston Children’s Hospital, 300 Longwood Avenue, Boston, MA 02115
4 Arnold Palmer Children’s Hospital, 83 West Columbia Street, Orlando, FL 32806
5 Center for Pediatric Orthopaedics, Phoenix Children’s Hospital, 1919 East Thomas Road, Phoenix, AZ 85016
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Investigation performed at The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania

A commentary J. Eric Gordon, MD, is linked to the online version of this article at jbjs.org.

Disclosure: None of the authors received payments or services, either directly or indirectly (i.e., via his or her institution), from a third party in support of any aspect of this work. One or more of the authors, or his or her institution, has had a financial relationship, in the thirty-six months prior to submission of this work, with an entity in the biomedical arena that could be perceived to influence or have the potential to influence what is written in this work. No author has had any other relationships, or has engaged in any other activities, that could be perceived to influence or have the potential to influence what is written in this work. The complete Disclosures of Potential Conflicts of Interest submitted by authors are always provided with the online version of the article.

Copyright © 2013 by The Journal of Bone and Joint Surgery, Inc.
J Bone Joint Surg Am, 2013 Apr 03;95(7):585-591. doi: 10.2106/JBJS.L.00203
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The modified Dunn procedure has rapidly gained popularity as a treatment for unstable slipped capital femoral epiphysis (SCFE), but limited data exist regarding its safety and efficacy. The purpose of this study was to present results and complications following this procedure in a large multicenter series.


We reviewed the outcomes of all patients who had been treated with the modified Dunn procedure by five surgeons from separate tertiary-care institutions. All slipped capital femoral epiphyses were defined as unstable according to the Loder criteria. Patients with less than one year of follow-up and those with an underlying endocrinopathy or syndrome were excluded. All surgical procedures were performed by pediatric orthopaedic surgeons who had specific training in the modified Dunn procedure. Operative reports, outpatient records, and follow-up radiographs were used to determine the demographic information, type of fixation, final slip angle, presence of osteonecrosis, and any additional complications. Standardized surveys were administered to determine the pain level (0 to 10 scale), satisfaction (0 to 100 scale), function (modified Harris hip score, 0 to 91 scale), and activity level (UCLA [University of California Los Angeles] activity score, 0 to 10 scale) at time of the most recent follow-up.


Twenty-seven patients (twenty-seven hips) with a mean of 22.3 months (range, twelve to forty-eight months) of follow-up met the inclusion criteria. Four patients (15%) had broken implants at three to eighteen weeks after surgery and required revision fixation. Seven patients (26%) developed osteonecrosis at a mean of 21.4 weeks (range, ten to thirty-nine weeks), with each surgeon having at least one case of osteonecrosis. The mean slip angle at the time of the most recent follow-up was 6° (95% confidence interval, 2° to 11°). Patients who did not develop osteonecrosis had significantly better clinical results compared with those who developed osteonecrosis, as demonstrated by a lower mean pain score (0.3 compared with 3.1, p = 0.002), higher level of satisfaction (97.1 compared with 65.8, p = 0.001), higher modified Harris hip score (88.0 compared with 60.0, p = 0.001), and higher UCLA activity score (9.3 compared with 5.9, p = 0.031).


This largest reported series of unstable slipped capital femoral epiphyses treated with the modified Dunn procedure demonstrated that the procedure is capable of restoring anatomy and preserving function after a slip but that implant complications and osteonecrosis can and do occur postoperatively.

Level of Evidence: 

Therapeutic Level IV. See Instructions for 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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