Effect of suture size and type on bone cutout in transosseous tendon repairs.

PURPOSE: We compared bone cutout of polyester and polyblend suture in 2 suture sizes with static and cyclic loading in a Sawbone model (Pacific Research Laboratories, Vashon, WA). METHODS: Polyester and polyblend sutures in both No. 2 and No. 5 sizes were placed through transosseous tunnels in closed-cell polyurethane foam and tied over the bar of an electromechanical load frame at a fixed height. Seven sutures in each group were pulled at a rate of 1 mm/s until bone cutout occurred. Another set of 28 sutures were cyclically loaded at increasing loads until failure. RESULTS: With static and cyclic loads, No. 5 polyester suture (Ethibond; Ethicon, Somerville, NJ) and No. 5 polyblend suture (FiberWire; Arthrex, Naples, FL) had a higher cutout load than the No. 2 sutures (P < .001). No. 2 polyblend suture had a higher static failure load than No. 2 polyester suture (P = .02). With cyclic loading, No. 2 polyblend suture had a higher load to cutout than No. 2 polyester suture (P = .01), and No. 5 polyblend suture had a higher load to cutout than No. 5 polyester suture (P = .003). CONCLUSIONS: No. 2 sutures showed bone cutout at lower forces under static and cyclic loading as compared with No. 5 sutures in this Sawbone model, and no decrease in performance with regard to bone cutout was noted with polyblend as compared with polyester. CLINICAL RELEVANCE: No. 5 polyester or polyblend suture may be preferable to No. 2 suture to avoid bone cutout in tendon-to-bone repair, and No. 5 polyblend may be preferable to No. 5 polyester to avoid bone cutout.

Krackow locking stitch versus locking premanufactured loop stitch for soft-tissue fixation: a biomechanical study.

PURPOSE: To biomechanically compare construct elongation under loading conditions and to compare load to failure for the locking premanufactured loop stitch versus the Krackow stitch. METHODS: Twenty porcine Achilles tendons were randomly assigned to receive the locking Krackow stitch with No. 2 FiberWire (Arthrex, Naples, FL) or the locking premanufactured loop stitch with No. 2 FiberLoop (SpeedWhip; Arthrex). Each tendon was pre-tensioned 3 times at 100 mm/min to 100 N for removal of slack, preloaded to 50 N to simulate tension applied clinically, and cyclically loaded at 200 mm/min to 200 N for 200 cycles. Total elongation of both suture strands was measured at each stage. Each tendon was loaded to failure. RESULTS: Elongation (mean ± standard deviation) in the Krackow group and the SpeedWhip group did not differ with initial loading at 50 N (4.5 ± 1.0 mm and 5.0 ± 1.7 mm, respectively; P = .4) or with cyclic loading (15.6 ± 5.7 mm and 17.0 ± 2.6 mm, respectively; P = .5). Load to failure was significantly higher in the SpeedWhip group as compared with the Krackow group (344.0 ± 23.1 N and 301.3 ± 24.4 N, respectively; P = .001). CONCLUSIONS: In a porcine tendon model, the locking loop stitch group was not significantly different regarding construct elongation with initial or cyclic loading compared with the Krackow stitch group. These findings suggest that the locking loop stitch has adequate strength to serve as an alternative to the Krackow stitch in procedures where the Krackow stitch is used. The elongation data suggest that augmentation or protection with early stress postoperatively would be needed with the locking loop stitch as with the Krackow stitch clinically. CLINICAL RELEVANCE: Similar elongation in the 2 constructs suggests that this locking loop stitch has adequate strength to serve as an alternative to the Krackow stitch in procedures where the Krackow stitch is used.

Restoration of longitudinal forearm stability using a suture button construct.

PURPOSE: This study proposed a method of restoring the longitudinal stability of the forearm provided by the central band of the interosseous membrane (IOM) by using a percutaneously placed suture button construct. We hypothesized that supporting the forearm IOM with a suture button construct would restore longitudinal stability in a cadaveric model of the Essex-Lopresti lesion. METHODS: We assessed 7 adult cadaver upper extremities radiographically for evidence of previous elbow, forearm, or wrist fracture. Each limb was mounted onto a materials testing system with the elbow held at 90° and the forearm in neutral. The intact specimen was loaded cyclically at 134 N to determine the native mobility of the forearm segment. Each specimen was tested after each of the following steps: radial head removal, transection of the IOM, and suture button construct reconstruction of the IOM. After the final reconstruction, each specimen was examined for forearm range of motion and evidence of neurovascular injury. RESULTS: Removal of the radial head and sectioning of the IOM sequentially increased average proximal migration of the radius by 3.6 and 7.1 mm, respectively. After reconstruction with the suture button construct, the IOM was restored to the intact state with only the radial head removed. Forearm rotation was not compromised by the reconstruction, and there was no evidence of neurovascular injury in any specimen. CONCLUSIONS: A percutaneously placed suture button construct can restore the longitudinal stability provided by an IOM. The method described did not limit forearm rotation. We encountered no neurovascular injury in the specimens tested in this series. This construct may be an effective adjunct when combined with bony reconstruction to treat longitudinal forearm axis injuries.

Core weave versus Krackow technique for Achilles tendon repair: a biomechanical study.

BACKGROUND: The Krackow stitch, commonly used for Achilles tendon repair, leaves the bulk of the stitch on the surface of the tendon as a possible nidus for adhesion. The proposed core weave stitch leaves a minimal amount of suture material on the tendon surface. The functional strength of the core weave stitch compared with the Krackow and the optimal number of throws, or stitches crossing the surface of the tendon, with this stitch are not known. MATERIALS AND METHODS: Twenty-one matched pairs of fresh-frozen cadaveric Achilles tendons were transected and randomly assigned to receive a 4-stranded stitch, either Krackow or core weave, with three, five, or seven throws. The samples were cyclically loaded to 75, 125 and 175 N for 1000 cycles at each load until failure, defined as 5 mm of elongation. RESULTS: No significant difference in failure load was observed between the Krackow and core weave groups at any number of throws or within the groups based on number of throws. Failure load for the different number of throws in the Krackow group approached significance (p = 0.10), with higher failure load with three throws. CONCLUSION: Functional strength of the core weave stitch and the Krackow stitch did not differ between groups with three, five, and seven throws. There was no significant difference in strength based on throws in either group. CLINICAL RELEVANCE: The proposed core weave stitch provides functional strength similar to that of the Krackow stitch for tendon repair with reduced suture material on the tendon surface.

Krackow locking stitch versus nonlocking premanufactured loop stitch for soft-tissue fixation: a biomechanical study.

PURPOSE: The purpose of this study was to biomechanically compare the Krackow stitch, an established locking stitch, with a new nonlocking premanufactured stitch for soft-tissue fixation. We evaluated suture construct elongation under loading and load to failure to compare the 2 stitches. METHODS: Twenty porcine Achilles tendons were randomly assigned to receive the locking Krackow stitch with No. 2 FiberWire or the nonlocking SpeedWhip stitch with No. 2 FiberLoop (Arthrex, Naples, FL). Each prepared tendon was mounted in a servohydraulic load frame, and the 2 free suture strands were knotted over the bar of the machine. Each tendon was pretensioned to 100 N to simulate the removal of slack, preloaded to 50 N to simulate tension applied clinically with suture tying over the post, and cyclically loaded at 200 mm/min to 200 N for 200 cycles. Total elongation of both suture strands was measured at each stage. Each tendon was loaded to failure. RESULTS: During preloading, the SpeedWhip group elongated significantly more than the Krackow group (65.6 +/- 22.5 mm v 14.9 +/- 5.9 mm, P < .001). During cyclic loading, the SpeedWhip group also showed significantly higher elongation than the Krackow group (23.5 +/- 8.7 mm v 11 +/- 4.5 mm, P = .02). The load to failure for the Krackow and SpeedWhip groups was not significantly different (376.2 +/- 39.8 N and 337.3 +/- 103.8 N, respectively; P = .65). With load to failure, suture breakage at the knot occurred in every specimen without further pullout of the suture. CONCLUSIONS: The nonlocking stitch applied in a manner consistent with manufacturer guidelines was significantly less secure than the locking Krackow stitch in a porcine Achilles tendon model. CLINICAL RELEVANCE: On the basis of these findings, the Krackow stitch remains the preferred method for suture fixation of soft-tissue grafts.

Fresh osteochondral total ankle allograft transplantation for the treatment of ankle arthritis.

BACKGROUND: Fresh osteochondral total ankle allograft transplantation has been reported in the literature with survival rates between 50% and 92% at 1- to 12-years followup. The goal of this study was to present the results of total ankle allografts from another institution. MATERIALS AND METHODS: Twenty-nine patients underwent osteochondral total ankle transplant at our institution between July 2003 and July 2005. The mean patient age was 41 years old and the mean followup duration was 2 years. RESULTS: At followup, 14 of the 29 transplants had been revised to a repeat ankle transplant, prosthetic total ankle arthroplasty, or bone block arthrodesis. In addition, 6 of the remaining 15 transplants were deemed to be radiographic failures due to allograft fracture, allograft collapse, or progressive loss of joint space. The remaining 9 allografts (31%) were considered successes. In comparing the success versus the failure group, patients who were older, who had a lower body-mass index, and who had minimal preoperative angular deformity did significantly better. CONCLUSION: This is the largest series of osteochondral total ankle allograft transplants reported in the literature to date. There is an extremely high rate of failure associated with this procedure, and we currently consider it only rarely in patients who are too young for ankle replacement, have excellent range of motion, low body mass index, normal radiographic alignment, and who refuse arthrodesis.

Periarticular locking plate vs intramedullary nail for tibiotalocalcaneal arthrodesis: a biomechanical investigation.

Augmented retrograde intramedullary (IM) nail fixation was compared with augmented periarticular locking- plate fixation for tibiotalocalcaneal arthrodesis. Specimens in 10 matched pairs were randomly assigned to a fixation construct and loaded cyclically in dorsiflexion. The groups did not differ in initial or final stiffness, load to failure, or construct deformation. No correlation was found between bone mineral density and construct deformation for either group. A humeral locking plate may be a viable alternative to an IM nail for tibiotalocalcaneal fixation in cases not amenable to IM nailing.

TightRope versus fiber mesh tape augmentation of acromioclavicular joint reconstruction: a biomechanical study.

BACKGROUND: The standard Weaver-Dunn reconstruction of the acromioclavicular (AC) joint does not provide adequate superoinferior or anteroposterior stability. Augmentation methods such as tape cerclage have been described. A new method of augmentation with the Arthrex TightRope is available. HYPOTHESIS: A Weaver-Dunn reconstruction augmented with the TightRope will provide superior superoinferior and anteroposterior stability to the AC joint as compared with a Weaver-Dunn reconstruction augmented with Mersilene fiber tape cerclage. STUDY DESIGN: Controlled laboratory study. METHODS: Six matched pairs of cadaveric shoulders underwent Weaver-Dunn AC joint reconstructions and were randomly assigned to receive either the TightRope device or tape cerclage augmentation. Translation in 2 planes was measured in the intact state under load and after 1 load cycle and 2000 load cycles. RESULTS: TightRope-augmented repair showed less superoinferior translation (mean +/- standard error) than cerclage-augmented repair in initially repaired (1.6 +/- 0.1 mm vs 5.0 +/- 1.1 mm, P = 0.03) and cyclically loaded (2.1 +/- 0.1 mm vs 5.8 +/- 1.2 mm, P = 0.02) conditions. TightRope repairs were stiffer than the native ligaments in the superoinferior plane. Less anteroposterior translation was observed with TightRope versus cerclage augmentation (initially repaired, 6.8 +/- 0.4 mm vs 18.8 +/- 2.6 mm, P < 0.001; cycled, 15.0 +/- 1.4 mm vs 28.3 +/- 2.7 mm, P = 0.01), but neither method maintained normal anteroposterior laxity after 1500 cycles compared with the intact state. CONCLUSION: Superoinferior and anteroposterior translation with TightRope augmentation was lower than with tape cerclage. CLINICAL RELEVANCE: TightRope augmentation of a Weaver-Dunn procedure could provide increased protection for AC joint reconstruction, allowing for earlier mobilization and more aggressive early rehabilitation. The potential clinical effect of additional tightening in the superoinferior direction beyond that of the native joint remains an issue for further study.