Locking Loop Suture Research Articles

Effect of the cross-sectional area of locking loops in flexor tendon repair.

An experimental study was performed using human cadaver flexor tendons to determine whether the size of the cross-sectional area encompassed by the locking loop suture configuration affected the biomechanical properties of tendon repair. Increasing the cross-sectional area of the locking loops from 10% to 50% resulted in a proportionate increase in the ultimate tensile strength of the repair and a small increased propensity for gapping. Overlapping the 2 locking loops without increasing the total cross-sectional area increased the propensity for gapping without increasing the ultimate strength.

The Strength of Achilles Tendon Repair: An In Vitro Study of the Biomechanical Behavior in Human Cadaver Tendons

Eighteen fresh frozen human Achilles tendons were used to test the ultimate strength of repaired tendon "ruptures." Three methods, the Kessler, the Bunnell, and the locking loop, were used to test the initial strength of Achilles tendon repair. The Kessler and Bunnell methods are current standard clinical configurations described for Achilles tendon repair. Under uniform and standardized laboratory conditions, the specimens were loaded to failure. The locking loop suture method was substantially stronger than either of the other two standard configurations. The latter two did not differ significantly from each other. The results of this study may be clinically relevant in terms of the choice of the repair method for surgically treated Achilles tendon ruptures.

Modified Transarticular External Skeletal Fixation for Support of Achilles Tenorrhaphy in Four Dogs

SummaryAchilles tendon ruptures in four dogs were treated with tenorrhaphy using a modified Kessler locking loop suture pattern and postoperative immobilization in partial extension of the tibiotarsal joint. The temporary immobilization of the tibiotarsal joint was achieved with a modified transarticular external skeletal fixation (MTESF). After predrilling the bone, the first fixation pin was placed in the distal tibia and the second in the calcaneus; they were connected with medial and lateral connecting bars. This immobilization method was easy to apply and to maintain during the postoperative period. The modified transarticular external skeletal fixation was removed between five and eight weeks after the operation. All four tendons healed, and all of the dogs returned to normal function. Modified transarticular external skeletal fixation is an alternative method of immobilization of the tibiotarsal joint for support of healing Achilles tenorrhaphies in dogs.Achilles tendon ruptures in four dogs were treated with tenorrhaphy and postoperative temporary immobilization of the tibiotarsal joint. The immobilization was achieved using a modified bilateral transarticular external skeletal fixation connecting the distal tibia and the calcaneus. All four tendons healed, and all of the dogs returned to normal function.

In Vitro Comparison of the Krackow and Locking Loop Suture Patterns for Tenorrhaphy of Flat Tendons

SummaryTenorrhaphy of 20 pairs of canine patellar tendons, was by a modification of the Krackow suture pattern on one of the pair and a single locking loop suture pattern on the contralateral tendon. The tenorrhaphies were pulled apart at a rate of 127 cm/min. The mode of failure for all tendons was disruption of the tendon and the suture material pulling out of the tendon. The mean maximum load for the locking loop suture pattern was 67.2 N (S.D. 7.8), compared to 61.3 N (S.D. 9.3) for the modified Krackow suture pattern. The mean energy absorbed to maximum load was 0.54 Joules (J) (S.D. 0.168) for the locking loop and 0.37 J (S.D. 0.12) for the modified Krackow. The mean stiffness was 4846 N/m (S.D. 803) for the locking loop and 5573 N/m (S.D. 921) for the modified Krackow.This study indicated the locking loop suture pattern was significantly better than the modified Krackow suture pattern in maximum strength (p = 0.03), total energy absorbed to failure (p = 0.0004) and stiffness (p = 0.004). Both suture patterns are suitable for use in flat tendons or ligaments based on their maximum strength. However, the effect of the modified Krackow suture pattern on vascularity and healing has not been evaluated.The locking loop suture pattern proved to be significantly better than the modified Krackow suture pattern in maximum strength, total energy absorbed to failure and stiffness.

A Comparison of Repair Methods for Gap Healing in Equine Flexor Tendon

In nine horses (18 forelimbs), a 3 cm section of superficial digital flexor tendon was removed and the tendons were repaired with immobilization for 6 weeks and (1) no suture (n = 6); (2) a double locking loop tenorrhaphy with carbon fiber (n = 6); or (3) a double locking loop tenorrhaphy with size 2 nylon suture (n = 6). Clinical assessment, gross evaluation, morphometry, histology, and mechanical testing were performed on two limbs from each treatment group at weeks 6, 12, and 24. At weeks 6 and 12, the unsutured tissue was less mature than the tissue sutured with nylon. By week 24, the carbon fiber repair had breaking stress (mean, 12.5 M Pa) similar to the unsutured repair (mean, 10.6 M Pa). There was necrosis and a granulomatous foreign body reaction around the carbon fiber. The nylon suture repair had significantly greater strength per unit area (mean breaking stress, 20.4 M Pa) because of a smaller area of repair tissue in the gap (mean, 3.6 cm2). At week 24, the nylon suture repair tissue was the most mature with the least inflammation of the three repair methods. A nylon double locking loop suture was the preferred method for equine flexor tenorrhaphy of a tendon gap because of greater breaking stress, histologic maturity, biocompatibility, and the adequate functional and cosmetic outcome.

In Vitro Comparison of the Three Loop Pulley and Locking Loop Suture Patterns for Repair of Canine Weightbearing Tendons and Collateral Ligaments

Both triceps tendons and the medial collateral ligaments of both stifles of 10 freshly euthanized dogs were sharply transected. One tendon and one ligament of each dog were sutured with a three loop pulley pattern, and the opposite tendons and ligaments were sutured with a locking loop pattern. The tendons and ligaments were harvested with their muscular and bony attachments. The anastomoses were slowly tested in tension until failure occurred. The amount of tensile load required to produce failure of the anastomosis, the amount of distraction of the sutured ends prior to failure, and the modes of failure were recorded. In both tendons and ligaments, the three loop pulley pattern provided significantly greater tensile strength (p < 0.01) and allowed significantly less distraction between the sutured ends (p < 0.01) than the locking loop pattern. In tendons, disruption of the suture material was the most common mode of failure with both patterns. In ligaments, both patterns failed most commonly by pulling free from the tissue.

Forces produced by medial gastrocnemius and soleus muscles during locomotion in freely moving cats.

5. During the step cycle the peaks of both MG and SOL force profiles occur before the end of the yield (E2) phase, as both muscles undergo active lengthening. In contrast, peak MG and SOL forces during vertical jumping coincide with the end of active lengthening and the onset of ankle extensor shortening. 6. The results are consistent with the hypothesis that the inherent stiffness of active muscle during the step cycle is an important factor in the control of force output from hindlimb extensor muscles in locomotion. The division of labor between MG and SOL and the absolute force levels required from the MG during the full range of hindlimb movements in posture, locomotion, and jumping appear to be precisely matched to the very different characteristics of the motor-unit populations composing these synergistic muscles.