The "Giftbox" repair of the Achilles tendon: a modification of the Krackow technique

Plunge-Freezing Cryopreservation of Tendons

Allograft transplantation is an important method for tendon reconstruction after injury, and its clinical success highly relies on the storage and transportation of the grafts. Cryopreservation is a promising strategy for tendon storage. In this study, we report a novel cryopreservation agent (CPA) formulation with a high biocompatibility for tendon cryopreservation. Mainly composed of natural zwitterionic betaine and the biocompatible polymer poly(vinylpyrrolidone) (PVP), it exhibited ideal abilities to depress the freezing point and inhibit ice growth and recrystallization. Notably, after cryopreservation via plunge-freezing for 1 month, Young's modulus (144 MPa, 98% of fresh tendons) and ultimate stress (46.7 MPa, 99% of fresh tendons) remained stable, and the cross-linking of collagen microfibers, protein structures, and glycosaminoglycan (GAG) contents changed slightly. These results indicate that the formulation (5 wt % betaine and 5 wt % PVP in phosphate-buffered saline, PBS solution) effectively maintains the biomechanical properties and tissue structure. This work offers a novel cryopreservation method for tendons and may also provide insights into the long-term preservation of various other tissues.

Biomechanical Comparison of Nonlocked Minimally Invasive and Locked Open Achilles Tendon Simulated Rupture Repairs

BACKGROUND

Open repair of Achilles tendon ruptures is associated with a risk of infection and other wound complications. Although percutaneous repairs reduce these complications, they may increase the risk of nerve injury. This study was designed to determine whether a percutaneous nonlocking repair can approach the gapping resistance offered by a standard open repair under conditions approximating typical postoperative physiotherapy.

METHODS

Ten pairs of cadavers Achilles tendons were transected in situ 5 cm above the insertion. One tendon from each pair was repaired using an open 4-strand Krackow locking loop, and the contralateral tendon was repaired with the Achillon system using the same suture material. Displacement transducers were attached to the medial, lateral, anterior, and posterior aspects of the tendon, spanning the repair. Each tendon underwent 1000 tensile loading cycles to 86.5 N, simulating passive ankle range-of-motion physiotherapy. Gapping was documented on the 1st, 50th, 100th, 500th, and 1000th cycles. The ultimate tensile strength of each repaired tendon was then measured by distracting until gross failure occurred.

RESULTS

Gapping of the percutaneous repairs exceeded that of conventional open repairs on the first, 500th, and 1000th load cycles. All 10 conventionally repaired tendons withstood 1000 load cycles without gross failure, but 4 of 10 percutaneous minimally invasive repairs failed, one on the 9th load cycle and the others between the 100th and 500th cycles. On average, tendons repaired with the open technique withstood 66% greater tensile load in failure testing than those repaired with the percutaneous technique.

CONCLUSION

Open Krackow Achilles tendon repairs may better withstand more aggressive postoperative physiotherapy than nonlocked percutaneous repairs.

CLINICAL RELEVANCE

The study suggests that surgeons should consider locking suture approaches to avoid loss of repair integrity with early motion.

Chronologic Changes in the Elastic Modulus of a Healing Achilles Tendon Rupture Measured Using Shear Wave Elastography

BACKGROUND

Shear wave elastography (SWE) has been used to examine the elasticity of a ruptured Achilles tendon; however, the healing process of a ruptured tendon has not been studied yet. This study aimed to detail the change in mechanical properties of a healing Achilles tendon rupture managed conservatively or surgically using SWE.

METHODS

Using a prospective cohort study design, we evaluated the patients treated conservatively (conservative group) and surgically (surgical group) with the "gift-box" technique for an isolated index acute Achilles tendon rupture during their healing process. SWE measurements were taken of both the injured and uninjured sides every 4 weeks up to 24, 36, and 48 weeks after treatment. Additionally, tendon thickness and power Doppler (PD) grade were measured at the same time points as SWE measurements. The American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot rating system score and Achilles tendon Total Rupture Score (ATRS) were compared at 24 and 48 weeks.

RESULTS

The ruptured Achilles tendon obtained an SWE value comparable with the unruptured side at 12 weeks in the conservative group and at 4 weeks with surgical group. The surgical group had significantly higher SWE values up to 24 weeks compared with the conservative group. Additionally, this group had a significantly larger increase in tendon thickness in nearly all periods. Both treatment groups were comparable regarding the PD grade, AOFAS score, and ATRS.

CONCLUSION

SWE is a convenient noninvasive method to determine the progress of the healing process after tendon injury. Our analysis using SWE has revealed the detailed chronologic changes in SWE values and related mechanical properties of a healing Achilles tendon rupture, which can be used for devising appropriate rehabilitation protocols.

LEVEL OF EVIDENCE

Level II, prospective cohort study.

Jigless knotless internal brace versus other open Achilles tendon repairs using a progressive rehabilitation protocol: a biomechanical study

BACKGROUND

The jigless knotless internal brace surgery (JKIB), a modified minimal invasive surgery (MIS) for acute Achilles tendon injury, has advantages of preventing sural-nerve injury in MIS and superficial wound infection in open surgery, as demonstrated in previous clinical research. However, to date, biomechanical testing has not yet been validated.

MATERIALS AND METHODS

Sixty fresh porcine Achilles tendons were used to compare the JKIB with other open surgery techniques, the four-stranded Krackow suture (4sK) and the triple-bundle suture (TBS) in biomechanical testing with cyclic loading set at 1 Hz. This approach simulated a progressive rehabilitation protocol where 20-100 N was applied in the first 1000 cycles, followed by 20-190 N in the second 1000 cycles, and then 20-369 N in the third 1000 cycles. The cycles leading to repair gaps of 2 mm, 5 mm, and 10 mm were recorded. The survival cycles were defined as repair gap of 10 mm.

RESULTS

With respect to survival cycles, a significant difference was found among the three groups, in which the TBS was the most robust, followed by the JKIB and the 4sK, where the mean survived cycles were 2639.3 +/- 263.55, 2073.6 +/- 319.92, and 1425.25 +/- 268.96, respectively. Significant differences were verified via a post hoc analysis with the Mann-Whitney U test after the Bonferroni correction (p < 0.017).

CONCLUSIONS

The TBS was the strongest suture structure in acute Achilles tendon repair. However, the JKIB could be an option in acute Achilles tendon repair with the MIS technique due to it being more robust than the 4sK, which has been typically favored for use in open repair.

Clinical Outcomes and Complications Following Limited Open Achilles Repair Without an Instrumented Guide

BACKGROUND

We report the clinical outcomes and complications following our limited open incision Achilles tendon repair technique without instrument guides.

METHODS

A total of 33 patients were included in this study. We recorded pre- and postoperative scores on the Foot and Ankle Disability Index (FADI), visual analog scale (VAS), and the Foot and Ankle Outcome Score (FAOS). Subgroup analyses were performed for acute (<2 weeks) and subacute (2-6 weeks) Achilles tendon repairs. A P value <.05 was considered significant for all statistical analyses.

RESULTS

The median time from injury to surgery was 10.0 days (range, 1-45 days). At a median follow-up of 3.7 years (range, 1.0-9.8 years), the average pre- and postoperative outcome scores improved significantly for the following: FADI index (49.1-98.4, P < .001), VAS (4.8-0.2, P < .001), FAOS Pain (54.8-99.2, P < .001), FAOS Symptoms (84.6-97.0, P < .001), FAOS activities of daily living (61.4-97.2, P < .001), FAOS Sports and Recreational Activity (39.5-98.5, P < .001), and FAOS quality of life (39.7-88.7, P < .001). There were no significant differences between pre- and postoperative outcome scores between the acute and subacute Achilles repair groups. There were no wound complication, reruptures, or reoperations in the entire cohort.

CONCLUSION

Patients showed improvements in postoperative patient-reported outcome scores with minimal complications. There was no significant difference in outcomes for acute vs subacute repairs. Our limited open incision Achilles tendon repair, which required no additional targeting instrumentation, had favorable midterm results.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Achilles Tendon Repair With Modified Giftbox Technique Using Nonabsorbable Suture Loops

Background:

Achilles tendon ruptures occur most commonly in male individuals aged between 30 and 60 years.

Indications:

Surgical options for treatment of acute midsubstance Achilles tendon ruptures in the athletically active population include open, mini-open, and percutaneous techniques.

Surgical Technique:

The giftbox suture configuration has been popularized by multiple authors. Here, a modified giftbox technique for Achilles tendon repair is shown in detail and uses nonabsorbable suture loops, a novel method for primarily repairing complete Achilles tendon ruptures.

Results:

This mini-open technique has demonstrated, at a minimum of 1-year follow-up, outcomes that are comparable with previously reported Achilles tendon repair procedures with no re-ruptures and low overall complication rates in the first 60 patients who have undergone this procedure. The mean time to release to unrestricted activity following repair by this technique is 24.3 weeks, which is earlier than most standard techniques.

Conclusion:

Achilles tendon repair using the modified gift box technique with nonabsorbable suture loops is a safe and reliable technique for repair of midsubstance tendon ruptures in athletically active patients. The mean time to release to unrestricted activity following repair by this technique is earlier than most standard techniques.

Comparison of the double loop knot stitch and Kessler stitch for Achilles tendon repair: A biomechanical cadaver study

Tendon elongation after Achilles tendon (AT) repair is associated with the clinical outcome. Reliable suture techniques are essential to reduce gap formations and to allow early mobilization. Cyclic loading conditions represent the repetitive loading in rehabilitation. The aim of this study was to compare the Kessler stitch and double loop knot stitch (DLKS) in a cyclic loading program focussing on gap formation. Sixteen human cadaveric ATs were transected and sutured using either the Kessler stitch or DLKS (eight matched pairs). The suture-tendon configurations were subjected to cyclic loading and additional ultimate load to failure testing using the Zwick 1446 universal testing machine. Each AT survived cyclic loading, with a mean gap formation less than 5 mm after 1000 cycles. The mechanical properties of the Kessler stitch and DLKS were not significantly different after cyclic loading with a mean displacement of 4.57 mm (± 1.16) for the Kessler stitch and 4.85 mm (± 1.14) for the DLKS (P = .76). There were no significant differences in the ultimate load testing (P = .85). Both bioprotective techniques prevent excessive gaping in cyclic testing when tendon loading is moderate. Our data and those from literature of gap formation in cyclic and ultimate loading allow the conclusion, that early aggressive AT loading after repair (e.g. full weightbearing) overstrain simple as well as complex suture configurations. Initial intraoperative tightening of the knots (preloading) before locking is important to decrease postoperative elongation.

Open Achilles Tendon Rerupture: A Case Report and Review of the Literature

In this report, we describe a rare case of open rerupture of an Achilles tendon following primary surgical repair. The rerupture occurred 12 weeks postoperatively and was associated with a transverse open wound perpendicular to the original surgical incision. This complication was successfully managed utilizing the preexisting transverse wound and a minimally invasive repair technique, minimizing further risk to the soft tissues overlying the tendon. This rare complication has only been described a few times in the literature and is likely associated with adhesions between the tendon repair and the subcutaneous tissues.

The biomechanical study of rupture of Achilles Tendon and repair by different suture techniques

Objective

To study the biomechanical properties of different suture methods, and to provide evidence for the clinical application of this suture methods in repairing acute Achilles tendon rupture.

Methods

Twenty four fresh frozen cadaver Achilles tendon specimens were collected and randomly divided into three groups (n=8), Group-A Bunnell suture method, Group-B Bosworth suture and Group-C anchor suture respectively. 5 N tensions were applied to tighten the tendon. The actual length of the tendon between the upper and lower clips was measured with a ruler. The length of the long axis and the short axis of the three sections of the tendon was measured by vernier caliper. The cross sectional area of the tendon was calculated according to the elliptical area formula and the mean value was obtained.

Results

There was no significant difference in the length and cross-sectional area of each tendon among three groups (F=0.26, P=0.86; F=0.09, P=0.96). There was no significant difference in the maximum load of tendon and failure displacement in Group A and B (P>0.05). The maximal load of Group-C was significantly larger than that of Group A and B (P<0.05), and there was no significant difference between the failure displacement and Group A and B (P>0.05).

Conclusion

Three suture methods can provide good biomechanical properties, but the anchor suture is more effective in solving the shortcomings of traditional methods. It is a safe and effective method, and is worthy of promotion.

[Biomechanical study of different suture methods in repairing tendon rupture]

Objective

To evaluate the biomechanical property of tendons repaired with the modified Kessler suture combined with " 8" suture, and to provide evidence for the clinical application of this suture methods in repairing acute Achilles tendon rupture.

Methods

Forty frozen flexor digitorum longus tendons from fresh pork hind leg were randomly assigned into 4 groups, 10 specimens each group. In group A, the tendons were dissected transversely at the midpoint to forming the model of tendon with transversely cutting injury. The tendons in groups B, C, and D were dissected transversely at the midpoint, then a 2 cm segment of tendon from the incision in each side was dissected longitudinally with 1 mm internal to forming " frayed tendon" model. All the tendons were sutured with2-0 non-absorbable suture material with different suturing methods: in group A, the tendons with transversely cutting injury model with Krackow suture, and in the groups B, C, and D with Krackow suture, Kessler suture, and the modified Kessler suture combined with " 8" suture separately. All repaired tendons were fixed onto the biomechanical testing machine. The length, width, and thickness of each side and midpoint of the tendons were recorded, and the cross-sectional area was calculated. The tendons were stretched at a speed of 15 mm/minutes until failure (suture avulsion or rupture). The computer automatically recorded the maximum load, stress, strain, the failure displacement, and the stiffness. These biomechanical parameters of tendons in different groups were analyzed and compared.

Results

There was no significant difference in the length and cross-sectional area of each tendon among 4 groups ( F=0.245, P=0.863; F=0.094, P=0.963). Two tendons in group B, 1 in group C, and 1 in group D were excluded because of tendon slipping; all tendons in group A and 8 tendons in group B failured due to suture rupture, 9 tendons in group C due to suture slipping, and 9 tendons in group D due to 3 sutures slipping from tendon tissue together. The maximum load, the maximum stress, the maximum strain, the failure displacement, and the stiffness of the tendons between groups A and B showed no significant difference ( P>0.05). The maximum load, the maximum stress, and the stiffness of the tendons in group D were larger than those in both groups B and C ( P<0.05), but no significant difference was found in the maximum strain and the failure displacement between groups B, C, and D ( P>0.05). The maximum load, the maximum stress, the failure displacement, and the stiffness of the tendons in group B were larger than those in group C ( P<0.05), but the difference of maximum strain between groups B and C was not significant ( P>0.05).

Conclusion

The modified Kessler suture combined with " 8" suture can provide better biomechanical property of the repaired tendon compared with other suture approaches.

Biomechanical Head-to-Head Comparison of 2 Sutures and the Giftbox Versus Bunnell Techniques for Midsubstance Achilles Tendon Ruptures

Background:

Acute midsubstance Achilles tendon ruptures are a common orthopaedic problem for which the optimal repair technique and suture type remain controversial. Head-to-head comparisons of current fixation constructs are needed to establish which stitch/suture combination is most biomechanically favorable.

Hypothesis:

Of the tested fixation constructs, Giftbox repairs with Fiberwire will exhibit superior stiffness and strength during biomechanical testing.

Study Design:

Controlled laboratory study.

Methods:

Two biomechanical trials were performed, isolating stitch technique and suture type, respectively. In trial 1, 12 transected fresh-frozen cadaveric Achilles tendon pairs were randomized to receive either the Giftbox-modified Krackow or the Bunnell stitch with No. 2 Fiberwire suture. Each repair underwent cyclic loading, oscillating between 10 and 100 N at 2 Hz for 1000 cycles, with repair gapping measured at 500 and 1000 cycles. Load-to-failure testing was then performed, and clinical and catastrophic failure values were recorded. In trial 2, 10 additional paired cadaveric Achilles tendons were randomized to receive a Giftbox repair with either No. 2 Fiberwire or No. 2 Ultrabraid. Testing and data collections protocols in trial 2 replicated those used in trial 1.

Results:

In trial 1, the Bunnell group had 2 failures during cyclic loading while the Giftbox had no failures. The mean tendon gapping after cyclic loading was significantly lower in the Giftbox repairs (0.13 vs 2.29 mm, P = .02). Giftbox repairs were significantly stiffer than Bunnell (47.5 vs 38.7 N/mm, P = .019) and showed more tendon elongation (5.9 ± 0.8 vs 4.5 ± 1.0 mm, P = .012) after 1000 cycles. Mean clinical load to failure was significantly higher for Giftbox repairs (373 vs 285 N, P = .02), while no significant difference in catastrophic load to failure was observed (mean, 379 vs 336 N; P = .61). In trial 2, there were no failures during cyclic loading. The Giftbox + Fiberwire repairs recorded higher clinical load-to-failure values compared with Giftbox + Ultrabraid (mean, 361 vs 239 N; P = .005). No other biomechanical differences were observed in trial 2.

Conclusion:

Simulated early rehabilitation biomechanical testing showed that Giftbox-modified Krackow Achilles repair technique with Fiberwire suture was stronger and more resistant to gap formation at the repair site than combinations that incorporated the Bunnell stitch or Ultrabraid suture.

Clinical Relevance:

A more in-depth understanding of the biomechanical properties of the Giftbox repair will help inform surgical decision making because stronger repairs are less likely to fail during accelerated postoperative rehabilitation.

Effect of Suture Caliber and Number of Core Strands on Repair of Acute Achilles Ruptures: A Biomechanical Study

BACKGROUND

Controversy exists regarding the ideal Achilles rupture treatment; however, operative treatment is considered for athletes and active patients. The ideal repair construct is evolving, and the effect of suture caliber or number of core strands has not been studied.

METHODS

Simulated mid-substance Achilles ruptures were performed in 24 cadavers. Specimens were randomized to three 6-core-strand style repair constructs: (1) 4 No. 2 sutures and two 2-mm tapes (2T); (2) 2 No. 2 sutures and four 2-mm tapes (4T); (3) 12 (double-6-strand) strand repair (12 No. 2-0 sutures [12S]). Repairs were subjected to a cyclic loading protocol representative of postoperative rehabilitation. These data were compared to a previously published standard open repair technique (6-core strands with No. 2 sutures) on 9 specimens tested under the same conditions.⁶ Results: No significant elongation differences were observed between the repair groups and the previously published standard repair group in the first 2 stages of the simulated rehabilitation protocol. Both the 2T and 12S repairs survived a significantly greater number of cycles to failure ( P = 0.0005, P = 0.0267, respectively) and had a significantly higher failure load ( P = .0005, P = .0118, respectively) compared to the previously published data. These 2 constructs consistently survived the advanced stages of the simulated rehabilitation protocol. The majority of repairs failed at the knots.

CONCLUSIONS

In this study, the 2T and 12S constructs survived the later stages of our simulated rehabilitation protocol, suggesting that they may be able to accommodate a more aggressive clinical rehabilitation protocol. Substituting suture-tape for 2 core strands or doubling the core strands with a smaller-caliber suture created a biomechanically stronger construct.

CLINICAL RELEVANCE

Achilles repair with an added nonabsorbable, high-tensile strength tape allowed for a stronger construct that may allow for a more aggressive, early rehabilitation protocol and earlier return to function.

Suture-Only Repair Versus Suture Anchor-Augmented Repair for Achilles Tendon Ruptures With a Short Distal Stump: A Biomechanical Comparison

Background:

Chronic noninsertional Achilles tendinosis can result in an acute Achilles tendon rupture with a short distal stump. In such tendon ruptures, there is a limited amount of adequate tissue that can hold suture, thus presenting a challenge for surgeons who elect to treat the rupture operatively.

Hypothesis:

Adding suture anchors to the repair construct may result in biomechanically stronger repairs compared with a suture-only technique.

Study Design:

Controlled laboratory study.

Methods:

Nine paired Achilles-calcaneus complexes were harvested from cadavers. An artificial Achilles rupture was created 2 cm proximal to the insertion on the calcaneus. One specimen from each cadaver was assigned to a suture-only or a suture anchor–augmented repair. The contralateral specimen of the same cadaver received the opposing repair. Cyclic testing was then performed at 10 to 100 N for 2000 cycles, and load-to-failure testing was performed at 0.2 mm/s. This was followed by analysis of repair displacement, gapping at repair site, peak load to failure, and failure mode.

Results:

The suture anchor–augmented repair exhibited a 116% lower displacement compared with the suture-only repair (mean ± SD, 1.54 ± 1.13 vs 3.33 ± 1.47 mm, respectively; P < .03). The suture anchor–augmented repair also exhibited a 45% greater load to failure compared with the suture-only repair (303.50 ± 102.81 vs 209.09 ± 48.12 N, respectively; P < .04).

Conclusion:

Suture anchor–augmented repairs performed on acute Achilles tendon ruptures with a short distal stump are biomechanically stronger than suture-only repairs.

Clinical Relevance:

Our results support the use of suture anchor–augmented repairs for a biomechanically stronger construct in Achilles tendon ruptures with a short distal stump. Biomechanically stronger repairs may lead to less tendon repair gapping and failure, increasing the ability to start early active rehabilitation protocols and thus improving patient outcomes.

A Prospective Study of Platelet-Rich Plasma as Biological Augmentation for Acute Achilles Tendon Rupture Repair

Acute Achilles tendon rupture is one of the most common tendon injuries in adults. We hypothesized that Platelet-Rich Plasma (PRP) can be used as biological augmentation for surgical treatment of acute Achilles tendon rupture. Our study is a prospective randomized controlled trial. Patients with acute Achilles tendon rupture undergoing surgical repair were randomly assigned into either control group or PRP group. End-to-end modified Krackow suture was performed in both groups. In the PRP group, PRP was injected into the paratenon sheath and around the ruptured tissue after the tendon was repaired. Postoperatively we evaluated isokinetic muscle strength at 3, 6, 12, and 24 months. In addition, ankle ROM, calf circumference, Leppilahti score, and the SF-36 score were evaluated at 6, 12, and 24 months after operation. At 3 months, the PRP group had better isokinetic muscle. The PRP group also achieved higher SF-36 and Leppilahti scores at 6 and 12 months. At 24 months, the PRP group had an improved ankle range of motion compared to the control group. Our study results suggest that PRP can serve as a biological augmentation to acute Achilles tendon rupture repair and improves both short and midterm functional outcomes.

A Biomechanical Comparison of an Open Repair and 3 Minimally Invasive Percutaneous Achilles Tendon Repair Techniques During a Simulated, Progressive Rehabilitation Protocol

BACKGROUND

While the nonoperative management of Achilles tendon ruptures is a viable option, surgical repair is preferred in healthy and active populations. Recently, minimally invasive percutaneous repair methods with assistive devices have been developed.

HYPOTHESIS/PURPOSE

The purpose of this study was to biomechanically analyze 3 commercially available, minimally invasive percutaneous techniques compared with an open Achilles repair during a simulated, progressive rehabilitation program. It was hypothesized that no significant biomechanical differences would exist between repair techniques.

STUDY DESIGN

Controlled laboratory study.

METHODS

A simulated, midsubstance Achilles rupture was created 6 cm proximal to the calcaneal insertion in 33 fresh-frozen cadaveric ankles. Specimens were then randomly allocated to 1 of 4 different Achilles repair techniques: (1) open repair, (2) the Achillon Achilles Tendon Suture System, (3) the PARS Achilles Jig System, or (4) an Achilles Midsubstance SpeedBridge Repair variation. Repairs were subjected to a cyclic loading protocol representative of progressive postoperative rehabilitation: 250 cycles at 1 Hz for each loading range: 20-100 N, 20-200 N, 20-300 N, and 20-400 N.

RESULTS

The open repair technique demonstrated significantly less elongation (5.2 ± 1.1 mm) when compared with all minimally invasive percutaneous repair methods after 250 cycles (P < .05). No significant differences were observed after 250 cycles between the Achillon, PARS, or SpeedBridge repairs, with mean displacements of 9.9 ± 2.2 mm, 12.2 ± 4.4 mm, and 10.0 ± 3.9 mm, respectively. When examined over smaller cyclic intervals, the majority of elongation, regardless of repair, occurred within the first 10 cycles. Within the first 10 cycles, open repairs achieved 71.2% of the total elongation observed after 250 cycles. Corresponding values for the Achillon, PARS, and SpeedBridge repairs were 81.8%, 77.9%, and 69.0%, respectively. No significant differences were observed in the total number of cycles to failure between minimally invasive percutaneous repairs and open repairs. Minor differences in the mechanism of failure were noted; however, the majority of all repairs failed at the suture-tendon interface.

CONCLUSION

Minimally invasive percutaneous repair techniques demonstrated a susceptibility to significant early repair elongation when compared with open repairs. However, the ultimate strengths of repairs (cycles to failure) were comparable across all techniques.

CLINICAL RELEVANCE

The reduced early elongation of open repairs suggests that patients treated with this technique may be able to progress through an earlier and/or more aggressive postoperative rehabilitation protocol with a lower risk of early irrevocable repair elongation or gapping about the repair site. However, in cases where cosmesis or wound-healing complications are of significant concern, minimally invasive percutaneous techniques provide a biomechanically reasonable alternative based on their repair strengths (cycles to failure). These repairs may need to be protected longer postoperatively to allow for biological healing and avoid early repair elongation and potential gapping between the healing tendon ends.

Initial Achilles tendon repair strength--synthesized biomechanical data from 196 cadaver repairs

PURPOSE

The study aim was to describe what kind of operative technique performs best with respect to initial strength after the surgical repair of acute Achilles tendon ruptures.

METHODS

We performed a systematic search of the keywords "Achilles tendon AND (suture strength OR biomechanics) AND (cadaver NOT animal)" in the online databases PubMed, EMBASE, CINAHL, and the Cochrane Library. We included studies that employed open, mini-open, or percutaneous Achilles tendon repair in human cadavers, and assessed some measure of tensile strength as a primary outcome.

RESULTS

Our search produced 11 relevant papers reporting results for Kessler, Bunnell, and Krackow sutures in open repair, as well as the Achillon device, the Ma-Griffith repair technique, the triple bundle technique and the "giftbox" technique. The weighted tensile strengths ranged from 81 to 453 N (mean 222.7 N) with the Triple Bundle technique in combination with # 2 Ethibond performing best with a mean of 453 N.

CONCLUSIONS

Due to the small sample sizes, different study designs, and heterogeneity of strength measurement techniques, definite recommendations on surgical technique cannot be made but presented information might help in the decision making process for foot and ankle surgeons.

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.

Over-the-top knot placement technique enhances tensile stability of tendon repairs

BACKGROUND

Currently a major concern for the surgical treatment of Achilles tendon rupture repairs is the creation of stable enough fixation to allow early range of motion. It was documented that the weakest point in a suture loop is the knot. Thus, we hypothesized that moving the knot away from the repair junction (over-the-top Krackow technique) would increase the strength of the repair.

MATERIALS AND METHODS

Transected bovine tendons were repaired by the traditional Krackow and over-the-top Krackow techniques using four suture materials (Fiberwire Nos. 5 and 2, Ethibond Nos. 5 and 2). Tendons were cyclically tested at incremental loads beginning from 50 N until 5-mm gap formation. Then all tendons were loaded to failure. The number of cycles to 5-mm gapping, ultimate failure loads and knot slip were compared using t-test and Mann-Whitney tests (with Tukey corrections for multiple comparisons).

RESULTS

Mean number of cycles to 5-mm gapping did not reveal significant differences (p = 0.113) between repair groups. Mean failure load of tendons repaired by over-the-top Krackow technique were significantly higher (p < 0.0001) for all four paired groups than tendons repaired by traditional Krackow technique. Ethibond No. 5, No. 2, and Fiberwire No. 2 suture repairs with over-the-top configuration did not reveal any knot slip.

CONCLUSION

Over-the-top Krackow technique increases the ultimate failure load of repaired tendons. But 5-mm gapping resistivity was not enhanced either by the technique or the suture material.

CLINICAL RELEVANCE

The knot itself is a stress-riser in the suture loop so we suggest that freeing it from tension by our modificiation may achieve more durable repairs.