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Device for Zone-II Flexor Tendon RepairA Multicenter, Randomized, Blinded, Clinical Trial
Brian W. Su, MD1; Michael Solomons, MD2; Andrew Barrow, MD3; Matshediso E. Senoge, MD4; Marco Gilberti, MD5; Lawrence Lubbers, MD6; Edward Diao, MD7; H. Matthew Quitkin, MD8; Melvin P. Rosenwasser, MD1
1 Department of Orthopaedic Surgery, The Trauma Training Center, New York Presbyterian Hospital, 622 West 168th Street, PH 11, Room 11-64, New York, NY 10032. E-mail address for M.P. Rosenwasser: ttc@columbia.edu
2 University of Cape Town, Room 128, Vincent Pallotti Hospital, Alexandra Road, Pinelands, Cape Town 7405, South Africa. E-mail address: docsol@iafrica.com
3 P.O. Box 902, Wendywood 2144, South Africa. E-mail address: andymels@global.co.za
4 Nelson R. Mandela School of Medicine, 5 Pfanner Road, Marion Hill Park, Pinetown 3610, South Africa. E-mail address: sened@hit.co.za
5 Via Usignolo 1, 20147 Milan, Italy
6 Hand and Microsurgery Associates, 3400 Olentangy River Road, Suite 200, Columbus, OH 43202
7 Department of Orthopaedic Surgery, University of California, San Francisco, 500 Parnassus Avenue, Room MU 320-W, Box 0728, San Francisco, CA 94143-0728. E-mail address:diaoe@orthosurg.ucsf.edu
8 415 Church Street, Suite 101, Vienna, VA 22180. E-mail address: matt.quitkin@verizon.net
View Disclosures and Other Information
A video supplement to this article is available from theVideo Journal of Orthopaedics.A video clip is available at the JBJS web site, www.jbjs.org. TheVideo Journal of Orthopaedicscan be contacted at (805) 962-3410, web site: www.vjortho.com.
In support of their research or preparation of this manuscript, one or more of the authors received grants or outside funding from Ortheon Medical, Winter Park, Florida. In addition, one or more of the authors received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity (Ortheon Medical). No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, educational institution, or other charitable or nonprofit organization with which the authors are affiliated or associated.
Investigation performed at Columbia University Medical Center, New York, NY, Groote Schuur Hospital, Cape Town, Johannesburg General Hospital, Johannesburg, and King Edward VIII Hospital, Durban, South Africa

The Journal of Bone and Joint Surgery, Incorporated
J Bone Joint Surg Am, 2005 May 01;87(5):923-935. doi: 10.2106/JBJS.C.01483
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Background: The stainless-steel Teno Fix tendon-repair device has improved biomechanical characteristics compared with those of suture repair, and it was well tolerated in a canine model. The purpose of this study was to compare the Teno Fix with suture repair in a clinical setting.

Methods: Sixty-seven patients with isolated zone-II flexor tendon injury were randomized to be treated with a Teno Fix or a four-stranded cruciate suture repair. There were eighty-five injured digits: thirty-four were treated with the Teno Fix, and fifty-one served as controls. A modified Kleinert rehabilitation technique was employed, with active flexion starting at four weeks postoperatively. Patients were followed for six months by blinded observers who determined the range of motion, Disabilities of the Arm, Shoulder and Hand (DASH) score, pinch and grip strength, and pain score on a verbal scale and assessed swelling and neurologic recovery. Adverse outcomes, including device migration and rupture, were monitored at frequent intervals.

Results: Nine of the fifty-one suture repairs ruptured, whereas none of the Teno Fix repairs ruptured (p < 0.01). Five of the nine ruptures were caused by resistive motion against medical advice. There were no differences between the two groups in terms of range of motion, DASH score, pinch and grip strength, pain, swelling, or neurologic recovery. The Teno Fix group had slightly slower resolution of pain and swelling compared with the control group. Of the patients who were available for follow-up at six months, sixteen of the twenty-four treated with a Teno Fix repair and nineteen of the twenty-seven treated with a control repair had a good or excellent result. One Teno Fix device migrated and extruded secondary to a wound infection. Of all eighty-five digits that were operated on, four were thought to have tendons of inadequate size to accommodate the device and nine were deemed to have inadequate exposure to allow placement of the anchors.

Conclusions: The Teno Fix is safe and effective for flexor tendon repair if the tendon size and exposure are sufficient. Tendon repairs with the Teno Fix have lower rupture rates and similar functional outcomes when compared with conventional repair, particularly in patients who are noncompliant with the rehabilitation protocol.

Level of Evidence: Therapeutic Level I. 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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    Brian W. Su, M.D.
    Posted on July 15, 2005
    Dr. Su and Dr. Rosenwasser respond to Dr. Meals
    Dept., Orthopaedic Surgery, New York Presbyterian Hospital, New York, NY 10032

    Dear Dr. Meals:

    The Journal defines Level I evidence as a high-quality randomized controlled trial with statistically significant difference or no statistically significant difference but narrow confidence intervals. This study randomized sixty seven consecutive patients to either the stainless steel Teno Fix repair or a control suture repair. As with any randomized clinical trial, there were patients that did not receive the treatment selected by the randomization. In this trial all tendons were evaluated regardless of randomization for (1) Tendon dimensions sufficient to accept the device and (2) Transection location which would allow the distal anchor to be placed. As stated on pg 930 of the manuscript, of the 41 digits initially randomized to the Teno Fix, seven were reassigned to a control repair because of inadequate distal tendon for repair with the device. None of the changes in surgical repair were secondary to inadequate tendon size as the four tendons judged too small to accept the device anchors were all originally randomized to the control suture repair. The seven tendons which were switched to a suture repair at surgery were done solely because of an inadequate distal stump to allow for anchor placement. At the time of the study, techniques for intraosseous anchor placement were not available. Currently, in similar situations the anchor would be placed without difficulty with a transosseous technique.

    Changes in repair technique for a distal injury pattern were not related to patient selection regarding anticipated compliance with therapy. In a subset analysis, there were no significant differences between the outcomes of the digits that were switched into the control group from the Teno Fix group. In addition, we have re-analyzed the data after omitting those digits which were changed during surgery to the control group. Our conclusions are the same with a dramatic decrease in the rupture rate in the Teno Fix group which remains the only statistical difference between the two groups.

    We reaffirm that all patients were blinded to the repair technique as were the therapists and clinical evaluators . All patients were assigned an identification code for the study. The randomization code was not broken until the completion of the study. We are confident that this study qualifies as a high-quality randomized trial providing Level I evidence to the readership.

    Regarding the management of FDS lacerations, we, along with other hand surgeons do not routinely repair FDS lacerations with concomitant FDP lacerations in order to minimize work of flexion underneath the pulley system. As stated on page 927 of the manuscript, the FDS stump was left as a gliding bed for the repair as well as to maintain the vascular supply to the FDP. The vinculae were preserved to protect the vascular input to the tendon if they were not already damaged by the original injury. Of note, FDS lacerations were not repaired in either group thereby not biasing the results toward either group. FDS lacerations were not left unrepaired in order to allow more room for the FDP tendon following repair. On the contrary, we feel that the single strand of 2-0 stainless steel suture that crosses the repair site is less bulky than the four stranded control suture repair. Regarding the effects of the repair on work of flexion, one of the authors the manuscript (E.D.) has recently performed a cadaveric work of flexion study comparing the Teno Fix repair to both 2 and 4-stranded suture repairs. (personal communication) The authors found no statistically significant differences in increase of work of flexion between the three repairs. Therefore, we encourage those authors who routinely repair FDS to continue to do so even when using the Teno Fix device.

    Lastly we would like to address your observation regarding patient number 204, in which the device extruded secondary to infection. The patient reported that he was eighteen years old at the time screening and enrollment into the study. However, upon examination of established medical records after the patient had been enrolled, the patient was noted to be sixteen years old. We do not feel that the subsequent infection was related to the patient’s age but acknowledge that the patient should have been excluded from the study. We have reviewed the records of all remaining patients and find that they meet all inclusion criteria for this study.

    We hope that this response has answered some of your questions and concerns regarding this clinical trial.

    Brian W. Su, M.D.

    Melvin P. Rosenwasser, M.D.

    Roy A. Meals
    Posted on June 16, 2005
    Device for Zone-II Flexor Tendon Repair

    To the Editor:

    With great interest, our local hand journal club recently discussed this article. Although we applaud the much needed and growing trend toward obtaining and reporting Level I evidence, we have several concerns on which we would appreciate having the authors comment.

    We question whether this work truly qualifies as Level I evidence. Although the patients were randomized to suture or Teno Fix treatment groups before surgery, the surgeons changed certain patients from the experimental arm to the control arm of the study once they had exposed the lacerations. The manuscript states that only tendons large enough to contain the Teno Fix device were retained in that arm of the study. The opportunity for intra-operative alteration of the randomization plan for any reason clearly selects the more substantial tendons for the experimental repair and also introduces a bias to eliminate patients from the experimental group that may be perceived to be less compliant with the rehabilition protocol.

    Additionally, it is not clear whether the patients were blinded to the type of repair they received. If not, there is once again the opportunity for bias on the part of the surgeon, therapist and patient regarding the type of the repair and the anticipated superior/inferior outcome.

    On another note, among the 85 injured digits in both arms of the study, all had flexor digitorum superficialis lacerations in addition to flexor digitorum profundus lacerations. Only one FDS laceration was repaired. Acceptable current practice usually includes FDS repair along with FDP repair if for no other reason than to improve the vincular blood supply to the repaired deep tendon. We have concern about the Teno Fix device adding substantial bulk to the tendon repair and, of course, this effect would be minimized when the flexor digitorum superficialis is left unrepaired. Should JBJS's readers choose to use the Teno Fix, do the authors advise that the FDS not be repaired to allow for more room of the bulky FDP tendon?

    Finally, we note in the Materials and Methods section that "all patients were at least eighteen years of age at the time of repair," yet in the Results section, one of the patients who developed an infection that led to extrusion of the Teno Fix device was "a sixteen-year-old boy."

    We look forward to the authors' response to further our understanding of the proper application of this intriguing device for tendon repair.

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