Device-assisted tensioning is associated with lower rates of graft failure when compared to manual tensioning in ACL reconstruction

Needleless graft preparation for anterior cruciate ligament reconstruction with 4-strand semitendinosus autograft: a biomechanical in vitro study using a porcine model

BACKGROUND

Ruptures of the anterior cruciate ligament (ACL) are common injuries. Reconstruction using autologous grafts is recommended to prevent further damage and functional impairment. Grafts are usually prepared with stabilizing sutures. The aim of this study was to evaluate if a 4-strand semitendinosus autograft preparation technique is non-inferior to conventional preparation techniques with regard to maximum tensile strength threshold.

METHODS

Fresh porcine flexor tendons were used as specimens in this study. Four different preparation techniques for quadruple-folded tendons were compared. Group 1 three suture FiberWire® (n = 20) and Group 2 one suture FiberWire® (n = 20) using Krakow stitches, Group 3 (n = 10) using SPEEDTRAP® and piercing the autograft and 4 (n = 9) using SPEEDTRAP® without piercing the autograft for preparation. Biomechanical tensile testing included 50 sinusoidal cycles of preloading between 50 and 150 N at 1 Hz and load-to-failure was measured at 20 mm/min.

RESULTS

Failure at the maximum load occurred at the filament for all samples, whereas failure of the suture/tendon interface was not observed. Load-to-failure was significantly higher in Group 1 (711 ± 91 N) than in all other groups. When comparing groups 2-4 load-to-failure was significantly higher in Group 2 (347 ± 24 N) than in Group 3 (258 ± 25 N, p < 0.02) but not than in Group 4 (325 ± 26N).

CONCLUSION

In all 4 Groups the load to failure was higher than the maximum tension force on the construct that will be applied by hand (182N). Therefore, the needleless preparation technique seems to be a valuable alternative to conventional techniques for the insertion of the graft into the joint during joint-near tibial fixation technique.

Whip-Lock Stitch Is Biomechanically Superior to Whipstitch for Semitendinosus Tendons

Purpose

To assess the biomechanical performance of different stitching methods using a suturing device by comparing the elongation, stiffness, failure load, and time to stitch completion in cadaveric semitendinosus tendons (STs) and quadriceps tendons (QTs).

Methods

A total of 24 STs and 16 QTs were harvested from cadaveric knee specimens (N = 40). Samples were randomly divided into 2 groups: whipstitch (WS) and whip-lock (WL) stitch. Both tendon ends were clamped to a graft preparation stand, and a 2-part needle was used to place 5 stitches, each 0.5 cm apart. Stitching time was recorded. Samples were preconditioned and then underwent cyclic loading from 50 to 200 N at 1 Hz for 500 cycles, followed by load-to-failure testing at 20 mm/min. Stiffness (in newtons per millimeter), ultimate failure load (in newtons), peak-to-peak displacement (in millimeters), elongation (in millimeters), and failure displacement (in millimeters) were recorded.

Results

Completion of the WS was significantly faster than the WL stitch in the ST (P < .001) and QT (P = .004). For the ST, the WL stitch exhibited higher ultimate failure loads and construct stiffness than the WS. Regarding the QT, the WL stitch showed higher stiffness and displacement than the WS; however, the ultimate failure load was higher for the WS in the QT. The ultimate failure load in the QT was higher than that in the ST for both stitches. In the ST, only 25% of WSs and 100% of WL stitches failed due to suture breakage. In the QT, suture breakage led to the failure of 100% of both the WL stitches and WSs.

Conclusions

In the ST, the WL stitch resulted in improved biomechanical performance through higher ultimate load and fewer failures from tissue damage compared with the WS. In the QT, both the WS and the WL stitch showed similar biomechanical performance with ultimate failure loads above established clinical failure thresholds.

Clinical Relevance

Various types of ligament and tendon injuries require suturing to enable repair or reconstruction. The success of ligament or tendon surgery often relies on soft-tissue quality. It is important to investigate the biomechanical properties of stitching techniques that help preserve soft-tissue quality as a step to determining their clinical suitability.

Manual and Device-Assisted Hamstring Autograft Tensioning Yield Similar Outcomes following ACL Reconstruction

The optimal initial graft tension during ACL reconstruction is still a matter of debate. Manual tension is commonly applied to the graft during tibial fixation. However, this has been associated with a greater graft failure rate than that associated with device-assisted tensioning. This study aims to compare the clinical outcomes between the application of manual tension and the use of the ConMed Linvatec SE™ Graft Tensioning System during graft fixation while performing anatomic single-bundle ACL reconstruction.

METHODS

A prospective comparative study was conducted between September 2015 and May 2017. Sixty-four patients (mean age 29.3 years, range 14-45) with isolated ACL injuries (and who would be subjected to ACL reconstruction with a quadruple hamstring tendon graft) were divided into two groups. In Group A (n = 29), common tension was applied manually to both grafts. In Group B (n = 35), specific tension was applied to the grafts with the use of a tensioner device (ConMed Linvatec SE™ (Stress Equalization) Graft Tensioning System). A total of 60 N was applied to the semitendinosus, and 40 N was applied to the gracilis. Clinical outcomes were assessed at 6, 12, and 24 months.

RESULTS

There were no significant differences between the baseline demographic and clinical data among the patients of the two groups (all p > 0.05). The patients were followed up for a minimum of 24 months (mean ± SD). There were no significant differences in the side-to-side anterior knee laxity, the IKDC, the Lysholm Knee, and the Tegner Activity Scale scores for up to 24 months after operation. The pivot shift test was negative in all cases, and no graft failure was reported at a 2-year follow-up.

CONCLUSION

No significant differences were found with respect to postoperative anterior knee laxity, clinical outcomes, activity level, and patient satisfaction between the application of manual tension and the use of the graft-tensioning system during tibial fixation while performing anatomic single-bundle ACL reconstruction with a quadruple hamstring tendon graft. Further high-quality clinical studies are required to elucidate whether device-assisted tension is superior to manual tension.

Arthroscopically Assisted Tensionable Cerclage Reconstruction of an Acromioclavicular Separation With Combined Fixation of the Coracoclavicular and Acromioclavicular Ligaments

A variety of surgical techniques are currently available to manage high-grade acromioclavicular (AC) separations, including hook plates/wires, nonanatomic ligament reconstruction, and anatomic cerclage with or without biological augmentation. Traditional reconstructions focused on the coracoclavicular ligaments alone and often were associated with high rates of recurrent deformity. Biomechanical and clinical data have suggested that additional fixation of the AC ligaments is beneficial. This Technical Note describes an arthroscopically assisted approach for combined reconstruction of the coracoclavicular and AC ligaments with a tensionable cerclage.

Factors Influencing the Initial Constraint Level of the Knee Joint and Its Effect on Clinical Outcomes After ACL Reconstruction With Hamstring Graft

Background

A force-based tension protocol that uses a certain amount of tension at graft fixation could still give rise to variations in initial constraint levels of the knee joint in terms of side-to-side difference (SSD) in anterior translation.

Purpose

To investigate the factors influencing the initial constraint level in anterior cruciate ligament (ACL)-reconstructed knees and compare outcomes according to the level of constraint in terms of anterior translation SSD.

Study Design

Cohort study; Level of evidence, 3.

Methods

Included were 113 patients who underwent ipsilateral ACL reconstruction using an autologous hamstring graft and had minimum 2-year follow-up outcomes. All grafts were tensioned and fixed at 80 N using a tensioner at the time of graft fixation. The patients were classified into the following 2 groups according to the initial anterior translation SSD, measured using the KT-2000 arthrometer: a physiologic constraint group with restored anterior laxity ≤2 mm (group P; n = 66) and a high-constraint group with restored anterior laxity >2 mm (group H; n = 47). Clinical outcomes were compared between the groups, and preoperative and intraoperative variables were evaluated to identify factors affecting the initial constraint level.

Results

Between group P and group H, generalized joint laxity (P = .005), posterior tibial slope (P = .022), and anterior translation measured in the contralateral knee (P < .001) were found to differ significantly. Measured anterior translation in the contralateral knee was the only significant predictor of high initial graft tension (P = .001). No significant differences were found between the groups regarding clinical outcomes and subsequent surgery.

Conclusion

Greater anterior translation measured in the contralateral knee was an independent predictor of a more constrained knee after ACL reconstruction. The short-term clinical outcomes after ACL reconstruction were comparable, regardless of the initial constraint level in terms of anterior translation SSD.

Intra-Articular Biomechanical Changes of the Meniscus and Ligaments During Stance Phase of Gait Circle after Different Anterior Cruciate Ligament Reconstruction Surgical Procedures: A Finite Element Analysis

OBJECTIVE

The debate on the superiority of single- or double-bundle for anterior cruciate ligament reconstruction has not ceased. The comparative studies on intra-articular biomechanics after different surgical reconstructions are rare. This study is to evaluate the biomechanical stress distribution intra-knee after single- and double-bundle anterior cruciate ligament reconstruction by three-dimensional finite element analysis, and to observe the change of stress concentration under the condition of vertical gradient loads.

METHODS

In this study, magnetic resonance imaging data were extracted from patients and healthy controls for biomechanical analysis. Patients included in the three models were matched in age and sex. The strength and distribution of induced stresses were analyzed in two frequently used procedures, anatomical single-bundle anterior cruciate ligament reconstruction and anatomical double-bundle anterior cruciate ligament reconstruction, using femoral-graft-tibial system under different loads, to mimic a post-operation mechanical motion. The three-dimensional finite-element models for normal ligament and two surgical methods were applied. A vertical force simulating daily walking was performed on the models to assess the interfacial stresses and displacements of intra-articular tissues and ligaments. The evaluation results mainly included the stress of each part of ligament and meniscus. The stress values of different parts of three models were extracted and compared.

RESULTS

The stress of ligament/graft at femoral side of three finite-element models was significantly higher than at tibial side, while the highest level was observed in single-bundle reconstruction finite-element model. With the increase of force, the maximum stress in the medial (7.1-7.1 MPa) and lateral (4.9-7.4 MPa) meniscus of single-bundle reconstruction finite-element model shifted from the anterior horn to the central area (p = 0.0161, 0.0479, respectively). The stress was shown to be at a lower level at femoral side and posterior cruciate ligament of intra-knee in two reconstruction finite-element models than that in normal finite-element models, while presented higher level at the tibial side than normal knee (p = 0.3528). The displacement of the femoral side and intra-knee areas in reconstruction finite-element models was greater than that in normal finite-element model (p = 0.0855).

CONCLUSION

Compared with the single-bundle technique, the graft of double-bundle anterior cruciate ligament reconstruction has better stress dissipation effect and can prevent postoperative meniscus tear more effectively.

High initial graft tension increases external tibial rotation on the axial plane after anatomical anterior cruciate ligament reconstruction

PURPOSE

The purpose of this study was to clarify the effects of applying different amounts of initial graft tension on the femorotibial positional relationship on the axial plane after anatomical ACL reconstruction.

METHODS

Eighty patients who underwent isolated ACL reconstructions using bone-patellar tendon-bone grafts were included in this study. In 40 of the 80 patients, the grafts were fixed at full knee extension with maximum manual force (high graft tension; Group H), whereas in the other 40 patients, the grafts were fixed at full knee extension with force of 80 N (low graft tension; Group L). One week postoperatively, all patients underwent computed tomography (CT) on bilateral knee joints with knee extension. The femorotibial positional relationship in axial CT images were retrospectively evaluated. Side-to-side differences (the surgical side minus the unaffected side) were calculated in these variables.

RESULTS

The side-to-side differences in anterior tibial translation distances were - 1.8 ± 2.1 mm in Group H and - 1.9 ± 2.0 mm in Group L, with no significant difference between the two groups. The side-to-side differences in tibial lateral shifts were - 0.2 ± 1.5 mm in Group H and 0.0 ± 1.4 mm in Group L, with no significant difference between the two groups. The side-to-side differences in tibial external rotation angles were 2.7 ± 4.5° in Group H and 0.3 ± 3.3° in Group L, with a significant difference between the two groups (P < 0.01).

CONCLUSION

Applying high initial graft tension (maximum manual force) resulted in the external rotation of the tibia against the femur just after anatomical ACL reconstruction. In contrast, applying low initial graft tension (80 N at full knee extension) did not change the femorotibial rotational relationship.

Comparison of anterior knee laxity immediately after anatomic double-bundle anterior cruciate ligament reconstruction: Manual tensioning vs tensioning boot techniques

Purpose

Tensioning technique at graft fixation is one of key factors for successful outcomes in ACL reconstruction. The tensioning boot, which had two tensioners and was fixed to the tibia with a bandage, was developed for precise graft tensioning. The purpose was to compare the anterior knee laxity between the manual tensioning and the tensioning boot techniques immediately after ACL reconstruction under anesthesia in order to elucidate the effectiveness of using the tensioning boot.

Methods

33 patients had anatomic double-bundle ACL reconstruction with semitendinosus tendon graft. After grafts were fixed with EndoButton-CL on lateral femoral cortex, grafts were tied to Double Spike Plate (DSP). Each graft was pre-tensioning with 20 N (totally 40 N) at 20 degree of flexion for 3 minutes using manually-held tensioner in 11 patients and using tensioner installed to tensioning boot in the remaining 22 patients before graft fixation, and were then fixed in the same manner. Tibial displacement under 67 and 89 N of tibial anterior load was measured by KT-2000 Knee Arthrometer under anesthesia before and immediately after operation.

Results

The anterior knee laxity in the operated knee was 4.5 ± 1.0 mm in the manual tensioning group and 2.9 ± 0.9 mm in the tensioning boot group at 89 N of anterior load, showing a significant difference. (P < .0001) The side-to-side difference in the manual tensioning group was significantly less than that in the tensioning boot group. (P = .002)

Conclusions

Anterior laxity of the operated knees as well as KT side-to-side difference immediately after ACL reconstruction was larger in the tensioning boot technique than the manual tensioning technique, when the graft was fixed in the same manner. Thus, the initial tension at graft fixation with the tensioning boot can be smaller than 40 N.

Continuous-Loop Tape Technique Has Greater Stiffness and Less Elongation Compared With Tied-Suture Fixation of Full-Thickness All-Soft Tissue Quadriceps Tendon Autografts

Background

Many graft fixation techniques are utilized for full-thickness soft tissue quadriceps tendon autografts during anterior cruciate ligament reconstruction (ACLR).

Purpose

To determine the tensile properties of all-soft tissue quadriceps tendon graft fixation using a tied-suture versus continuous-loop tape technique. It was hypothesized that the continuous-loop tape technique would have less cyclic elongation and greater ultimate load to failure and stiffness compared with a commonly used tied-suture technique.

Study Design

Controlled laboratory study.

Methods

Sixteen fresh-frozen human knee specimens were used to harvest a full-thickness all-soft tissue quadriceps tendon graft; half were secured using a Krackow suture technique with 2 braided sutures, and half were secured using a continuous-loop tape suspensory fixation button with a rip-stop stitch. Cyclic and permanent elongation, toe- and linear-region stiffness, and ultimate load were determined. Statistical analysis was performed at P <.05.

Results

The tied-suture fixation group demonstrated significantly higher permanent elongation (11.7 ± 3.6 vs 4.2 ± 1.0 mm, P < .001) and cyclic elongation (5.9 ± 1.3 vs 2.0 ± 0.4 mm, P < .001) compared with the continuous-loop tape fixation group. There was a significantly higher linear-region stiffness with continuous-loop tape fixation compared with tied-suture fixation (98.8 ± 12.7 vs 85.5 ± 7.5 N/mm, P = .022). No significant difference in ultimate load between groups (517.1 ± 149.2 vs 465.6 ± 64.6 N) was found. The mode of failure was tendon pull-through for the continuous-loop tape group and suture breakage in the tied-suture group (P < .001).

Conclusion

Continuous-loop tape fixation is superior to tied-suture fixation in regard to elongation and stiffness for all-soft tissue quadriceps tendon grafts, but there was no significant difference in ultimate load.

Clinical Relevance

Continuous-loop tape fixation of all-soft tissue quadriceps tendon grafts for ACLR is a valid technique with superior tensile properties.

Clinical studies of single-stage combined ACL and PCL reconstruction variably report graft tensioning, fixation sequence, and knee flexion angle at time of fixation

PURPOSE

In single-stage ACL-PCL reconstruction, there is uncertainty regarding the order of graft tensioning and fixation, as well as the optimal knee flexion angle(s) for graft fixation. A systematic review of clinical studies of single-stage combined ACL-PCL reconstruction was performed to determine whether a particular fixation sequence and/or knee flexion angle is associated with superior outcomes.

METHODS

A systematic review was performed according to PRISMA guidelines. All levels of evidence were included. All outcome measures were extracted, including physical examination values, radiographic measurements, and objective and subjective outcomes.

RESULTS

Of the 19 included studies, 17 tensioned and fixed the PCL before the ACL. Only four studies reported the methods/forces used for graft tensioning. Across studies, the ACL was fixed at variable knee flexion angles, from full extension to 70°. Conversely, 3 studies fixed the PCL at a knee flexion angle < 45°, while the remaining 16 studies fixed the PCL at a flexion angle > 70°. Patient-reported outcomes were qualitatively similar between groups.

CONCLUSIONS

This systematic review found considerable variability in graft tension, fixation sequence, and knee flexion angle at the time of fixation, with insufficient evidence to support specific surgical practices. Most commonly, the PCL is fixed before the ACL graft, with fixation occurring at a knee flexion angle between 70° and 90° and near full extension, respectively. The methodology for quantifying the forces applied for graft tensioning is rarely described. Given this clinical equipoise, future studies should consistently report these surgical details. Furthermore, prospective, randomized studies on the treatment of multiligament knee injuries are needed to improve outcomes in patients.

LEVEL OF EVIDENCE

IV.

Residual graft tension after graft fixation in anterior cruciate ligament reconstruction: Manual vs tensioning boot techniques

BACKGROUND

Graft fixation at quantitative tension using a manual tensioner was advocated in ACL reconstruction, while the measured tension that is based on the surgeon's hand with the tensioner decreases after graft fixation. Therefore, our purpose is to elucidate how effectively the pre-determined graft tension maintained after final fixation of the graft to the tibia using a tensioning boot system fixed to the calf with a bandage, while monitoring the graft tension based on tibia.

METHODS

Eight cadaveric legs (mean age: 83; 3 males and 5 females) underwent an anatomic double-bundle anterior cruciate ligament (ACL) reconstruction with hamstring tendon grafts. Two tension-adjustable force gauges were installed on the lateral femoral cortex beside the femoral tunnel. Then #5 strong suture wires through the loop end of grafts were tied to the force gauges using Endo-Buttons. After manual maximum load was repeatedly applied to each graft for 3 min, the grafts were fixed to the tibia with 10 N or 20 N at 20 degree of flexion with the following tensioning techniques using double spike plate system: (1) Manually tensioning technique (MT); (2) Tensioning boot technique with flexion-extension motion (TB-FE); and (3) Tensioning boot technique with repetitive pull (TB-RP). The residual tension at 20 was measured 3 min after grafts fixation, and also after 10 and 50 times of repeated flexion-extension motion. One-way repeated measures ANOVA was used for statistical analysis among the three techniques.

RESULTS

There were significant differences among three techniques fixing grafts with 10/20 N of initial tension in the residual tension 3 min after graft fixation and after 10 and 50 times of repeated flexion-extension motion. Among them, the residual tension in TB-RP was the greatest in most conditions.

CONCLUSION

TB-RP is the most secure procedure to maintain the graft tension closer to the intended initial tension in ACL reconstruction.

Is in-vivo 80 N tensioned quadrupled hamstring graft better than conventional unmeasured pull for arthroscopic ACL reconstruction

PURPOSE

To find clinical outcome of in-vivo standard 80 N tensioning of quadrupled hamstring graft during arthroscopic single bundle ACL reconstruction in comparison to traditional graft tensioning.

METHODS

Sixty cases of isolated ACL tears were included in this study. All cases underwent Arthroscopic ACL reconstruction with Tibial attachment sparing quadrupled hamstring graft. Cases were divided into group I and group II (30 cases each). Graft Tensioning in group 1 was conventional one-handed unmeasured pull and in group II it was measured tension of 80 N with tensionometer during graft fixation. Pre-operative and post-operative (12 months) Anterior tibial translation (ATT) was measured with KT-1000 arthrometer. Clinical outcome was measured using Lysholm knee scoring system at 6weeks, 3months, 6months, 12 months and compared statistically among both groups.

RESULTS

The mean pre-op ATT of 10.6 ± 2.04 mm (group I) & 10.83 ± 2 mm (group II) improved to 3.63 ± 1.16 mm (group I) & 3.63 ± 0.92 (group II) respectively at one year without significant difference (p value 1). The mean pre-op Lysholm score was 46.73 ± 6.77 (group I) and 45.97 ± 8.68 (group II). The mean Lysholm score at 6 weeks was 91.5 ± 2.78 (group I) and 93.43 ± 3.02 (group II) with significant difference (p value 0.014). At 3 months it was 95.4 ± 2.99 (group I) and 97.07 ± 2.07 (group II) with significant difference (p value 0.025). At 6 months it was 95.53 ± 2.46 (group I) and 97.5 ± 1.2 (group II) with significant difference (p value 0.0002). At 1 year it was 95.73 ± 2.22 (group I) and 97.8 ± 0.979 (group II) with significance (p value 0.0001).

CONCLUSION

The clinical score of ACL reconstruction is better when in-vivo 80 N tension is applied using tensionometer during graft fixation in comparison to conventional manual tensioning but there is no difference in ATT.

V, Dubey V, Kulkarni O, Shah HC. Graft Retensioning by Dialing of Suture Disk on Tibial-Side Fixation in Arthroscopic Anterior Cruciate Ligament Reconstruction: Pathak Pune Dialing Technique

Arthroscopic anterior cruciate ligament (ACL) reconstruction is a common procedure performed for symptomatic ACL tears, especially in athletes. The desired surgical end product with any surgical fixation device remains a taut ACL graft, which is crucial during postoperative rehabilitation to reduce the risk of knee instability and rerupture of the ACL graft. The purpose of this Technical Note and accompanying video is to describe a simple and cost-effective technique to easily retension the ACL graft after tibial fixation in ACL reconstruction using a suture disk device. The technique uses a simple suture disk device to provide strong tibial fixation, along with the unique ability to retension the ACL graft by dialing it in a clockwise direction.

The single-suture technique for anterior cruciate ligament graft preparation provides similar stability as a three-suture technique: a biomechanical in vitro study in a porcine model

PURPOSE

Numerous techniques have been described for the tibial-sided graft preparation in anterior cruciate ligament (ACL) reconstruction. The use of less suture material for graft preparation is thought to improve ingrowth and to reduce the risk for infection. At the same time, the suture construct should be strong enough to resist the surgeon's pull during tensioning of the transplant.

METHODS

In total, 39 fresh-frozen procine deep flexor tendons were used and prepared as four-strand grafts. In the three-suture group (n = 19), graft preparation was performed using three tibial-sided sutures, with each tendon end sutured separately. In the one-suture group (n = 20), a modified graft preparation using only one tibial-sided suture was applied. Each sample underwent load-to-failure testing (N_max) after cyclic pre-loading. To estimate intraoperative tension forces acting on the tibial-sided suture constructs, the maximal tension force of 26 volunteers on such a construct was measured using a load cell.

RESULTS

The biomechanical testing of the two different suture constructs showed a significantly higher load-to-failure for the three-suture group (711 N ± 91 N) compared to the one-suture group (347 N ± 24 N) (p = 0.0001). In both groups, the mode of failure was a tear of the suture in all samples. A failure of the suture-tendon interface was not observed in any case. The median maximal tension force on the construct applied by the 26 volunteers was 134 N (range 73-182 N).

CONCLUSION

The presented single-suture tendon graft preparation resisted to smaller failure loads than the conventional three-suture technique. However, no failures in the suture-tendon interface were seen and the failure loads observed were far beyond the tension forces that can be expected intraoperatively. Hence, the single-suture graft preparation technique may be a valuable alternative to the conventional technique.

Soft Tissue Fixation Strategies of Human Quadriceps Tendon Grafts: A Biomechanical Study

PURPOSE

To evaluate the effects of different stitching methods and suture diameters on the graft fixation of soft tissue human quadriceps tendon grafts for anterior cruciate ligament (ACL) reconstruction.

METHODS

The Krackow locking stitch (K), whipstitch (W), and baseball stitch (B) were combined with either a 2× no. 2 (#2) or a 1× no. 5 (#5) braided composite suture for graft fixation of 36 human quadriceps tendons in 6 groups. Biomechanical testing was performed using a cyclic protocol with loads between 0 and 100 N. The maximum load until failure, cyclic elongation, and failure mode were recorded.

RESULTS

The highest mean maximum load to failure was observed in the 2 Krackow stitch groups. The K#2 group had significantly higher load to failure values compared with those of the W#2 and B#2 groups (K#2, 553 ± 82 N vs W#2, 392 ± 107 N, P = .0349; K#2 vs B#2 366 ± 118 N, P = .0129). The mean cyclic elongation was lowest in the Krackow groups (K#2, 10.59 ± 2.63 mm; K#5, 13.66 ± 2.3 mm). The regular failure mode was the rupture of the suture for the Krackow stitch (8 of 12) and suture pullout for the whipstitch (11 of 12) and baseball stitch groups (12 of 12).

CONCLUSIONS

The double Krackow stitch with no. 2 braided composite suture exhibits a high maximum load to failure combined with a low amount of elongation in a biomechanical study for human quadriceps tendon soft tissue graft fixation. Unlike the whipstitch and the baseball stitch, it can solidly prevent suture pullout.

CLINICAL RELEVANCE

A safe soft tissue graft fixation technique is especially important for quadriceps tendon grafts with their laminar anatomical structure and physiologically varying diameter. Unlike other grafts for ACL replacement, it fully relies on the soft tissue suture fixation to resist the pullout force.