This multicenter prospective study from 3 centers compared the use of the Teno Fix versus a four-stranded cruciate suture repair for flexor tendon injuries. Eighty-five digits in sixty-seven patients with isolated Zone-II flexor tendon injuries were randomized to be treated with a Teno Fix or a four-stranded cruciate suture repair. Thirty-four were treated with a Teno Fix and fifty-one with a conventional four-stranded repair. Only one patient had repair of the FDS and this patient died from a CVA four weeks postoperatively and was not included in the study. A modified Kleinert rehabilitation technique was employed with active flexion starting at four weeks postoperatively. The technique for the Teno Fix included a modified Brunner incision with the requirement for at least 10-mm of tendon to be exposed on either side of the laceration. The Teno Fix device is composed of 2 intra-tendonous stainless steel anchors (a coil around a core) joined by a single multi-filament 2-0 stainless steel suture. Each anchor is 2.2 mm in diameter and 4.0 mm in length and the suture is 0.3 mm in diameter. The Teno Fix requires an intra-tendonous split initiated 1cm from the cut edge of tendon. These tenotomies are ultimately closed with 6-0 monofilament suture as well as a running circumferential 6-0 suture at the repair site. The four-stranded cruciate suture repair was performed with either a single 4-0 or 3-0 monofilament Prolene suture. A 6-0 epitendinous monofilament running suture was also placed on the conventional repair site. Of the forty-one digits that were initially randomized to the Teno Fix repair group, seven were switched into the control group because of inadequate surgical exposure to implant the device.
Nine (18%) of the fifty-one tendons that were repaired with the cruciate technique ruptured whereas none of the tendons repaired with the Teno Fix device ruptured. All ruptures occurred within six weeks after the primary repair and were felt to be due to noncompliance with therapy by prematurely using the hand for active resisted flexion earlier than dictated. Three of the nine ruptures occurred during the active motion phase of rehabilitation in patients who were compliant with the program. Seven of the ruptured repairs were treated with tendon grafting. Five of those repairs failed by suture pull-out and one by suture breakage. None of the ruptures were due to failure at the knot. The authors felt that there was slightly increased swelling in the Teno Fix group, however, there was no significant difference in the percentage of digits with an excellent-good result based on Strickland’s revised score. In addition, there was no significant difference between the two groups at any time point with respect to DASH scores. An infection did develop in three patients in the Teno Fix group and four patients in the control group. One of the infected digits resulted in extrusion of the Teno Fix device, which was subsequently removed. The mean functional DASH scores approached baseline preinjury scores without any difference between the two groups.
This multicenter study is the first to review the results of the Teno Fix device. In this study there were no ruptures using the Teno Fix device versus an 18% rupture rate within six weeks using the cruciate technique. This indicates that despite a four-strand repair with a locked peripheral running suture, compliance is an issue with conventional repairs. It appears that the Teno Fix may have greater resistance to rupture especially in the non-compliant patient. Overall this study shows that the Teno Fix device is a safe and effective repair technique for Zone-II injuries. It exhibited lower rupture rates with a similar functional recovery. The Teno Fix device, however, does require greater exposure in upwards of 20 cm of tendon around the laceration and a certain size caliber of tendon, although this was not specifically defined in the article. In addition, there is no evidence that the device caused any extra tendinous adhesions with little reaction on the tendon surface. Lastly, there was no significant difference in the duration of surgery between the two groups or of the complication rate.
Journal of Bone And Joint Surgery