A comparative biomechanical study of the krackow suture technique with three common percutaneous suture techniques in the treatment of Achilles tendon ruptures

BACKGROUND

The aim of this study was to compare the biomechanical resistance under tensile forces of the Krackow suture technique with the frequently used Dresden, Carmont & Maffulli, and Ma & Griffiths percutaneous repair techniques in bovine models of Achilles tendon rupture.

METHODS

Transverse Achilles tendon rupture models were created from 4 cm proximal of the calcaneal insertion point in a total of 20 bovine Achilles tendon specimens. These were randomly allocated to 4 groups and repaired with configurations appropriate to the Dresden, Carmont & Maffulli, Ma & Griffiths and Krackow techniques. Failure mechanisms were recorded with force values (as Newton units) creating a 5 mm gap and load to failure under tensile loading at a rate of 10 mm/sec in a static testing device.

RESULTS

In the Dresden technique group, the force required for a 5 mm gap was mean 41.21 ± 13.19 N and for load to failure, mean 193.83 ± 30.16 N, which were evaluated as statistically significantly higher than in the other techniques (p < 0.05). The lowest values were determined in the Ma & Griffiths technique group (5 mm gap: 11.06 ± 8.12 N, load to failure: 97.73 ± 29.60 N) but these were not significantly lower than the values in the Krackow and Carmont & Maffulli technique groups (p > 0.05).

CONCLUSION

The results of this study showed that the Dresden technique was biomechanically superior against tensile forces compared to the Krackow technique, and the other frequently used percutaneous techniques of Carmont & Maffulli and Ma & Griffiths.

All-Suture Anchor Repair of the Flexor Digitorum Profundus Insertion: A Biomechanical Comparison of 2 Suturing Techniques

PURPOSE

We compared 2 suturing techniques for reattachment of the flexor digitorum profundus (FDP) via all-suture anchor.

METHODS

We used fresh, matched-pair, cadaveric hands. We disarticulated the fingers at the proximal interphalangeal joints, preserving the proximal FDP. We released the FDPs at their distal insertion and placed an all-suture, 1.0-mm anchor at the center of each FDP footprint. Each anchor's sutures were used to reattach each FDP using 1 of 2 techniques: group H (n = 14) via horizontal mattress; group H + K (n = 12) via horizontal mattress with knots thrown and, with each suture tail, 3 proximal, running-locking, Krackow-type passes on the radial and ulnar FDP sides with the suture ends tied together. We excluded 2 specimens from the H + K group because of improper anchor placement. All other fingers in both groups were individually mounted in an MTS machine for FDP loading in the following sequence for 500 cycles each: (1) to 15 N to simulate passive motion forces; (2) to 19 N for short-arc active motion forces; and (3) to 28 N for full active motion forces. Specimens that had not failed during cyclic testing were then loaded to failure. We measured FDP-to-bone gapping via a digital transducer. We defined failure as >3-mm gapping.

RESULTS

The H + K group had significantly less gapping during cyclic loading up to 19 N and significantly higher load to failure. The H + K group failed exclusively at the anchor-bone level; the H group failed mostly by suture-tendon pullout.

CONCLUSIONS

The H + K group performed significantly better regarding cyclic and load-to-failure testing after FDP reattachment.

CLINICAL RELEVANCE

The H + K technique combines the benefits of horizontal-mattress tendon-to-bone apposition and Krackow-tendon locking. It converts the point of failure to the bone level rather than the suture-tendon level.

Biomechanical comparison of different suture materials with different techniques in tendon repair: An ex-vivo study

OBJECTIVES

Sheep Achilles tendons are used as an effective preclinical model of flexor tendon repair in plastic surgery, due to their biomechanical properties, which are similar to humans. The aim of this study was to examine the efficacy and biomechanical outcomes of suture materials and tendon repair techniques in flexor tendon repair.

MATERIAL AND METHODS

72 sheep tendons were obtained for a total of 12 different scenarios. Tendons were repaired using 4 different suture types and 3 different suture techniques. After repair, the tendons were fixed at both ends and subjected to biomechanical tests. Ultimate Failure Load (UFL) and 2-mm Gap Load (GL) per scenario were compared statistically within and between groups.

RESULTS

UFL and GL of all sutures were significantly different between the modified Kessler, Bunnell and Krackow techniques (P < 0.05), and between Monosorb, Ti-Cron and V-loc sutures (P < 0.05). UFL and GL according to repair technique were not significantly different for the Propilen suture (P > 0.05).

CONCLUSION

When UFL and GL were considered together, our findings indicate that optimal strength scenarios were for the modified Kessler technique using Monosorb or V-loc sutures.

Biomechanical Characterization of a New Locking Loop Stitch for Graft Fixation versus Krackow Stitch

Background

The purpose of this study was to quantify and compare the biomechanical characteristics of a new locking loop stitch (LLS), developed utilizing the concepts of both running locking stitch and needleless stitch, to the traditional Krackow stitch.

Methods

The Krackow stitch with No.2 braided suture and the LLS with 1.3-mm augmented polyblend suture tape were compared biomechanically. The LLS was performed with single strand locking loops and wrapping suture around the tendon, resulting in half the needle penetrations through the graft compared to the Krackow stitch. Twenty bovine extensor tendons were divided randomly into two groups. The tendons were prepared to match equal thickness and cross-sectional area. Each suture-tendon was stitched and preloaded to 5 N for 60 seconds, cyclically loaded to 20 N, 40 N, and 60 N for 10 cycles each, and then loaded to failure. The deformation of the suture-tendon construct, stiffness, yield load, and ultimate load were measured.

Results

The LLS had significantly less deformation of the suture-tendon construct at 100 N, 200 N, 300 N, and at ultimate load compared to the Krackow stitch (Krackow stitch and LLS at 100 N: 1.3 ± 0.1 mm and 1.0 ± 0.2 mm, p < 0.001; 200 N: 3.0 ± 0.3 mm and 1.9 ± 0.2 mm, p < 0.001; 300 N: 5.1 ± 0.6 mm and 2.9 ± 0.4 mm, p < 0.001; ultimate load: 12.8 ± 2.8 mm and 5.0 ± 1.2 mm, p < 0.001). The LLS had significantly greater stiffness (Krackow stitch and LLS: 97.5 ± 6.9 N/mm and 117.2 ± 13.9 N/mm, p < 0.001) and yield load (Krackow stitch and LLS: 66.2 ± 15.9 N and 237.9 ± 93.6 N, p < 0.001) compared to the Krackow stitch. There was no significant difference in ultimate load (Krackow stitch: 450.2 ± 49.4 N; LLS: 472.6 ± 59.8 N; p = 0.290).

Conclusions

The LLS had significantly smaller deformation of the suture-tendon construct compared to the Krackow stitch. The LLS may be a viable surgical alternative to the Krackow stitch for graft fixation when secure fixation is necessary.

Biomechanical Analysis of Lark-Loop, Lasso-Loop and Krackow Suture Technique in Tenodesis

OBJECTIVE

Strong tendon grasping is vital to the success of a tenodesis operation. The purpose of this study was to evaluate the initial tendon-fixation strength of the Lark-Loop technique in arthroscopic suprapectoral biceps tenodesis and compare it with others commonly used techniques.

METHODS

Thirty-three porcine superficial flexor digitorum tendons were harvested from a local slaughterhouse and randomly divided into three groups to perform three tendon fixation techniques (Lasso-Loop stich group, Lark-Loop stich group or Krackow stich group; 11 tendons each group) with a No. 2 suture, respectively. Each tendon was pre-tensioned in 5°N for 2 min and then cyclically loaded 5 to 30°N for 500 cycles to assess displacement. After cyclic loading, the tendon was loaded to ultimate tendon-suture configuration failure at the rate of 1 mm/s. Finally, the mode of failure and the construct stiffness of the tendon were recorded and calculated.

RESULTS

After cyclical loading, the displacement of the Lark-Loop group was equivalent to the Krakow group (P > 0.9999) but significantly smaller than the Lasso-Loop group (P = 0.0009). The ultimate load to failure for the Lark-Loop was equivalent to the Krakow technique group (P = 0.1463) but significantly greater than the Lasso-Loop group (P < 0.0001). The stiffness for the Lark-Loop was equivalent to the Krakow group (P = 0.4718) but significantly greater than the Lasso-Loop technique group (P < 0.0001). In the Lark-Loop and Krackow group, all the tendons failed by suture breakage, while all the tendons failed by suture cutting through the tendon in the Lasso-Loop technique group.

CONCLUSION

Lark-Loop suture technique has biomechanical properties comparable to Krackow and superior to the Lasso-Loop in terms of suture displacement, ultimate load to failure, and stiffness. Therefore, the Lark-Loop suture fixation technique may be beneficial for arthroscopic biceps tenodesis.

Biomechanical Comparison of a Novel Multiplanar, Perpendicular Whipstitch With the Krackow Stitch and Standard Commercial Whipstitch

Background:

Using alternating orthogonal suture throws with the looped whipstitch technique may allow enhanced suture fixation.

Hypothesis:

It was hypothesized that this novel multiplanar, perpendicular looped whipstitch (MP) technique would have improved biomechanical properties compared with the standard looped whipstitch (WS) and Krackow stitch (KS).

Study Design:

Controlled laboratory study.

Methods:

A total of 30 cadaveric tibialis anterior tendons were randomly assigned into 3 groups of 10. Tendons were secured to a custom clamp, and the other end was sutured using 1 of 3 techniques: the KS, WS, or novel MP. The MP was performed with alternating orthogonal throws starting right to left, then front to back, left to right, and back to front. Each technique used 4 passes of No. 2 FiberWire spaced 5 mm apart and ending 10 mm from the tendon end. Tendons were preloaded to 5 N, pretensioned to 50 N at 100 mm/min for 3 cycles, returned to 5 N for 1 minute, cycled from 5 to 100 N at 200 mm/min for 100 cycles, and then loaded to failure at 20 mm/min. Elongation was recorded after pretensioning and cycling and was measured both across the suture-tendon interface and from the base of the suture-tendon interface to markings on the suture limbs (construct elongation). One-way analyses of variance were performed, with Bonferroni post hoc analysis when appropriate.

Results:

There were no differences in cross-sectional area or stiffness among the 3 techniques. The ultimate load for WS (183.33 ± 57.44 N) was less compared with both MP (270.76 ± 39.36 N) and KS (298.90 ± 25.94 N) (P ≤ .001 for both). There was less construct elongation for KS compared with WS and MP for total displacement, measured from pretensioning to the end of cycling (P < .001). All 3 techniques saw a decrease in length (shortening) at the suture-tendon interface during testing. There was more shortening at the suture-tendon interface for WS compared with KS (P = .006).

Conclusion:

The KS appears superior, as it maximized strength while minimizing construct elongation or graft shortening. The ultimate load of the MP technique was greater than that of the standard technique but not significantly different from that of the KS technique.

Clinical Relevance:

The KS is preferred. If using a WS, multiplanar, perpendicular passes should be considered.

Single Incision Distal Biceps Repair With Hemi-Krackow Suture Technique: Surgical Technique and Early Outcomes

BACKGROUND

Many surgical methods exist for distal biceps repair. We present the technique and early outcomes of a series of distal biceps repairs completed with a novel suturing technique utilizing a hemi-Krackow locking stitch at the tendon-bone interface.

METHODS

A retrospective review was performed of patients who underwent primary distal biceps repair using a single anterior incision with 2 suture anchors utilizing a hemi-Krackow stitch. With both anchors, a locking stitch along the tendon edge was complimented by the other strand passing through the central aspect of the distal tendon and advanced to pull the tendon edge down to the bone with appropriate tension. Patients with revision surgery and the use of allograft were excluded. Clinical outcomes included elbow range of motion and grip strength. All patients completed a Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) questionnaire and reported satisfaction level, pain level, and any postoperative complications.

RESULTS

Fourteen patients with an average age of 51.3 years (range, 27.8-66.4 years) were included in the study. The dominant arm was injured in 9 cases. At an average of 16.4 months' follow-up (range, 6.8-34.3 months), all patients had elbow range of motion of 0° to >130°, and grip strength was 101.5% of the uninjured arm (range, 70.6%-121.4%). The Average QuickDASH score was 6.5 (range, 0-36.5).

CONCLUSION

Single incision biceps repair with suture anchor fixation using our hemi-Krackow stitch provided a strong repair allowing easy tensioning of the biceps tendon to bone and showed satisfactory functional outcomes at early follow-up. No patients required revision surgery, and there was only 1 case of transient nerve complaints.