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

Surgical Management of Chronic Achilles Tendon Ruptures: A Systematic Review and Proposed Treatment Algorithm

Background

As no evidence-based treatment guidelines exist for chronic Achilles tendon rupture (CATR), a systematic review of the literature was performed to compare the different treatment options and recommend a literature-based algorithm.

Methods

In June 2022, MEDLINE, Embase, and Cochrane Library databases were systematically reviewed based on the PRISMA guidelines. The level of evidence (LOE) and quality of evidence were evaluated, and statistics on clinical outcomes and complications were calculated.

Results

Twenty-seven studies with 614 patients were included. Three studies were LOE III and 25 studies were LOE IV. The mean Achilles tendon rupture score improved from a preoperative weighted mean of 38.8 ± 12.4 to a postoperative score 90.6 ± 4.7. The overall complication rate was 11.4%. Single techniques were used in 23 studies and dual techniques were used in 5 studies. The FHL tendon transfer was the most frequently used technique. We devised an algorithmic approach based on time from injury to surgical intervention and the length of the gap between the tendon stumps: >3 months: FHL transfer; <3 months (a) gap <2 cm, end-to-end repair; (b) gap 2 to 5 cm, gastrocnemius transfer, (c) gap >5 cm, semitendinosus autograft.

Conclusion

Surgical management of CATR produced improvements in patient-reported outcome scores at midterm follow up, but a high complication rate (11.4%) was noted. Our proposed treatment algorithm may assist in shared decision making for this complex problem.

A Critical Biomechanical Evaluation of Foot and Ankle Soft Tissue Repair

The objective of this article is to review the biomechanical stresses that occur during normal physiologic function of lower extremity soft tissue anatomic structures and to use this as a baseline for a critical analysis of the medical literature because it relates to surgical reconstruction following injury. The Achilles tendon, anterior talofibular ligament, plantar plate, and spring ligament are specifically evaluated.

Biomechanical comparisons of three minimally invasive Achilles tendon percutaneous repair suture techniques

BACKGROUND

While no gold standard exists for the management of Achilles tendon ruptures, surgical repair is common in healthy and active patients. Minimally invasive repair methods have become increasingly popular, while biomechanical equivalency hasn't been proven yet.

METHODS

A mid-substance Achilles tendon rupture was created 6 cm proximal to the calcaneal insertion in 27 fresh-frozen cadaveric ankles. Specimens were randomly allocated to 1 of 3 repair techniques: Huttunen et al. (2014) (1) PARS Achilles Jig System, Nyyssönen et al. (2008) (2) Achilles Midsubstance SpeedBridge™, Schipper and Cohen (2017) (3) Dresdner Instrument and subsequently subjected to cyclic loading with 250 cycles each at 1 Hz with 4 different loading ranges (20-100 N, 20-200 N, 20-300 N, and 20-400 N).

FINDINGS

After 250 cycles no significant differences in elongation were observed between PARS and Dresdner Instrument(p = 1.0). Furthermore, SpeedBridge™ repairs elongated less than either Dresdner Instrument (p = 0.0006) or PARS (p = 0.102). Main elongation (85%) occurred within the first 10 cycles with a comparable elongation in between 10 and 100 and 100-250 cycles. While all repairs withstood the first 250 cycles of cyclic loading from 20 to 100 N, only the PARS (468 ± 175) and Midsubstance SpeedBridge™ (538 ± 208) survived more cycles. Within all 3 groups suture cut out was seen to be the most common failure mechanism.

INTERPRETATION

Within all groups early repair elongation was seen. While this was least obvious within the SpeedBridge™ technique, ultimate strengths of repairs (cycles to failure) were comparable across PARS and SpeedBridge™ with a decline in the Dresdner Instrument group.

Modified triple Kessler with least risk of elongation among Achilles tendon repair techniques: a systematic review and network meta-analysis of human cadaveric studies

PURPOSE

Current treatment recommendations emphasize early loading, with preservation of tendon length and physiologic tension. The objective of this systematic review and network meta-analysis was to compare failure load and elongation after cyclic loading of Achilles tendon repair techniques at time-zero.

METHODS

The databases PubMed, CENTRAL and Web of Science were searched for all published in-vitro studies comparing Achilles tendon repair techniques, or augmentation with autografts/biomaterials, and reports of failure load or elongation after cyclic loading. Only studies using human cadaveric Achilles tendons and matched pairs, or randomized specimen allocation, were selected for quantitative synthesis. A network meta-analysis per primary outcome was performed. Results were summarized as P score rankings and their validity was assessed using statistical methods.

RESULTS

Sixteen studies, comprising 367 tendon repairs, were included. The following repair techniques were used (n = number of studies): Krackow (n = 8), Achillon (n = 4), double Krackow (n = 3), Bunnell (n = 3), Percutaneous Achilles Repair System (n = 3), Percutaneous Achilles Repair System Midsubstance (n = 2), Kessler (n = 3), double Kessler (n = 1), modified triple Kessler (n = 1), triple bundle (n = 1), a multifilament stainless steel cable-crimp technique (n = 1) and a double loop knot stitch (n = 1). Five studies assessed augmentation with autografts/biomaterials. Regarding the failure load, biomaterial augmented Krackow repairs occupied the first four positions in the ranking, followed by the multifilament stainless steel cable-crimp and Percutaneous Achilles Repair System Midsubstance techniques. Concerning elongation after cyclic loading, the triple Kessler was ranked first, followed by the Achillon and Percutaneous Achilles Repair System Midsubstance techniques. A negligible correlation between ranks was found (r_s = 0.11; p = 0.75n.s.), meaning that a higher repair tensile strength is not necessarily related to improved performance in regard to avoidance of elongation.

CONCLUSION

In the failure load network meta-analysis, biomaterial augmented Krackow repairs ranked highest, but noticeable statistical heterogeneity was found. Regarding elongation with cyclic loading, the modified triple Kessler stitch showed the highest probability of ranking first.

LEVEL OF EVIDENCE

Level IV.

An ex vivo biomechanical comparison of two suture materials and two pattern combinations for equine superficial digital flexor tendon tenorrhaphy

OBJECTIVE

To compare biomechanical characteristics of three-loop pulley (3LP) pattern versus Bunnell technique (BT) using polydioxanone (PDS) suture; to determine the influence of polyester tape (PT) versus PDS on the BT for equine superficial digital flexor tendon (SDFT) tenorrhaphy; to compare BT with PT versus 3LP with PDS.

STUDY DESIGN

Ex vivo biomechanical study.

SAMPLE POPULATION

Forty equine forelimb SDFT.

METHODS

Two experiments were performed: (1) 10 SDFT pairs were repaired with 3LP or BT using PDS; (2) 10 SDFT pairs were repaired with PDS or PT using BT. Load at failure, mode of failure, load at 2 mm gap, and gap at failure were obtained using a material testing machine.

RESULTS

In experiment 1, 3LP + PDS₁ had higher loads at failure (p < .001) and at 2 mm gap (p < .001), and smaller gap at failure than BT + PDS₁ (p = .024). In experiment 2, BT + PT₂ had higher loads at failure (p < .001) and at 2 mm gap (p = .001), and larger gap at failure (p = .004) than the BT + PDS₂ . 3LP + PDS₁ and BT + PT₂ mostly failed by suture/implant pull-through while BT + PDS failed by suture breakage. BT + PT₂ had greater load (p = .035) and gap at failure (p < .001) than 3LP + PDS_1, with no difference in load at 2 mm gap (p = .14).

CONCLUSION

The use of BT may be justified over 3LP if combined with PT. However, the larger size of the PT required stab incisions in the tendon for placement and was subjectively more difficult to place than PDS.

CLINICAL SIGNIFICANCE

The BT + PT, although the strongest among the tested repairs, would only be able to withstand 12%-24% of the load encountered by the SDFT at walk.

Open versus minimally-invasive surgery for Achilles tendon rupture: a meta-analysis study

INTRODUCTION

Despite the presence of various different surgical procedures, the preferable technique for repair of acute Achilles tendon ruptures is unknown and, therefore, object of discussions. The purpose of this meta-analysis was to compare clinical outcomes and complication-rates between the minimally invasive and the standard open repair of acute Achilles tendon ruptures.

MATERIALS AND METHODS

This meta-analysis was performed according to the PRISMA guidelines. In September 2019 the main databases were accessed. All clinical trials of evidence level I to III comparing minimally invasive vs. open surgery of Achilles tendon rupture were included in the present study. Only articles reporting quantitative data under the outcomes of interest were included. Missing data under the outcomes of interest warranted the exclusion from the present work. For the statistical analysis we referred to the Review Manager Software Version 5.3. (The Nordic Cochrane Centre, Copenhagen). Continuous data were analysed through the inverse variance method. For the effect estimate the mean difference was used. Dichotomous data were analysed through the Mante-Haenszel method via odd ratio effect measure. The confidence interval was set at 95% in all the comparisons. Values of P < 0.05 were considered statistically significant.

RESULTS

A total of 25 articles were included for meta-analysis. The funnel plot revealed poor data dispersion, attesting to this study a low risk of publication bias. The quality of the methodological assessment was moderate. Data from 2223 (1055 open, 1168 minimally invasive) surgical procedures were extracted. The mean follow-up was of 24.29 ± 22.4 months. The open group reported a lower value of post-operative palpable knot at last follow-up and a lower rate of sural nerve palsy. In the minimally-invasive group a shorter surgery duration and a lower rate of post-operative wound necrosis and reduced risk of wound scarring and adhesions has been evidenced. The minimally-invasive cohort detected the lowest values of superficial and deep infections. In both groups no significant difference was shown in re-rupture rate.

CONCLUSIONS

Compared to the minimally-invasive Achilles tendon reconstruction, the open procedure evidenced a lower rate of sural nerve palsy and postoperative palpable knot, whereas in the minimally-invasive reconstruction group quicker surgery duration, a lower rate of post-operative wound necrosis, superficial and deep infections and less scar tissue adhesions could be observed. No relevant discrepancies were detected among the two techniques in terms of post-operative re-rupture.

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.

Repair of chronic Achilles tendon rupture using Bosworth’s technique

Background:

A large number of ruptures of the Achilles tendon occurs in the watershed hypovascular region (zone II) of the tendon which is approximately 2–6 cm proximal to the insertion of tendon at calcaneum. Chronic Achilles tendon rupture in the watershed area makes end to end repair of tendon less feasible and the neglected distal stump is often inapt for repair. A number of surgical techniques have been described for repair of chronic Achilles tendon in zone II. Our study was conducted with the objective of determining the efficacy and functional outcome of Bosworth’s technique that involves gastrocnemius-soleus turndown of proximal Achilles tendon.

Materials and Methods:

The study was conducted in a total of five patients with chronic tear of Achilles tendon and the Bosworth technique was used for repair in all the patients. All the patients were followed up for a period of 1 year and the functional outcome was assessed by scoring system devised by Leppilahti et al.

Results:

four out of the five patients showed excellent functional at the end of 1 year follow up. A good functional outcome was seen in one of the patients. All the patients were able to resume work 6 months postoperatively.

Conclusion:

The Bosworth’s technique is an excellent surgical procedure for repair of chronic Achilles tendon rupture in the watershed zone of the tendon.

Patient-Reported Outcomes of Achilles Tendon Repair Using the Modified Gift-Box Technique With Nonabsorbable Suture Loop: A Consecutive Case Series

We sought to determine the early range of motion, complication rates, and 1-year patient-reported outcomes following Achilles tendon repair, using a modified gift-box suture loop technique. Sixty consecutive patients (49 males, mean age 36.2 ± 9.9 years) who underwent Achilles tendon repair with a modified gift-box suture loop technique performed by a single surgeon were prospectively enrolled. The range of motion at the final follow-up visit (mean 6 months) and the Achilles tendon rupture score (ATRS) and the complication rates at 1 year were obtained with 83% follow-up. The predictors of complications and ATRS were assessed. The mean operative time was 63.1 ± 10.8 minutes, which decreased throughout the case series (r = 0.46, p < .001). The mean plantarflexion at the final office evaluation was 31.7° ± 6.2°, dorsiflexion was 11.7° ± 6.3°, and total ankle arc of motion was 43.6° ± 9.7°; longer length of follow-up was associated with greater dorsiflexion (p = .008) and the total arc of motion (p = .008) but not with plantarflexion (p = .16). The overall rerupture rate was 1.7% (1 patient), wound complication rate was 1.7% (1 patient), and the overall complication rate was 6.7% (4 patients). No predictors of complications were identified. Complication rates did not differ between the first 30 (6.7%) cases and second 30 (6.7%) cases. The mean ATRS at 1 year was 81.8 ± 16.8 points. The rerupture and overall complication rates by 1 year were low. The range of motion, particularly dorsiflexion, improved through at least 6 months. Diabetic patients had lower 1-year ATRS than nondiabetic patients using this technique.

The elastic capacity of a tendon-repair construct influences the force necessary to induce gapping

PURPOSE

Most biomechanical investigations of tendon repairs were based on output measures from hydraulic loading machines, therefore, accounting for construct failure rather than true gapping within the rupture zone. It was hypothesized that the elastic capacity of a tendon-repair construct influences the force necessary to induce gapping.

METHODS

A tendon-repair model was created in 48 porcine lower hind limbs, which were allocated to three fixation techniques: (1) Krackow, (2) transosseous and (3) anchor fixation. Loading was performed based on a standardized phased load-to-failure protocol using a servohydraulic mechanical testing system MTS (Zwick Roell, Ulm, Germany). Rupture-zone dehiscence was measured with an external motion capture device. Factors influencing dehiscence formation was determined using a linear regression model and adjustment performed as necessary. A 3-mm gap was considered clinically relevant. Analysis of variance (ANOVA) was used for comparison between groups.

RESULTS

The elastic capacity of a tendon-repair construct influences the force necessary to induce gapping of 3 mm (F_3mm) [β = 0.6, confidence interval (CI) 0.4-1.0, p < 0.001]. Furthermore, the three methods of fixation did not differ significantly in terms of maximum force to failure (n.s) or F_3mm (n.s).

CONCLUSION

The main finding of this study demonstrated that the higher the elastic capacity of a tendon-repair construct, the higher the force necessary to induce clinically relevant gapping.

LEVEL OF EVIDENCE

Controlled biomechanical study.

Management of acute Achilles tendon ruptures: A review

Objectives

The incidence of acute Achilles tendon rupture appears to be increasing. The aim of this study was to summarize various therapies for acute Achilles tendon rupture and discuss their relative merits.

Methods

A PubMed search about the management of acute Achilles tendon rupture was performed. The search was open for original manuscripts and review papers limited to publication from January 2006 to July 2017. A total of 489 papers were identified initially and finally 323 articles were suitable for this review.

Results

The treatments of acute Achilles tendon rupture include operative and nonoperative treatments. Operative treatments mainly consist of open repair, percutaneous repair, mini-open repair, and augmentative repair. Traditional open repair has lower re-rupture rates with higher risks of complications. Percutaneous repair and mini-open repair show similar re-rupture rates but lower overall complication rates when compared with open repair. Percutaneous repair requires vigilance against nerve damage. Functional rehabilitation combining protected weight-bearing and early controlled motion can effectively reduce re-rupture rates with satisfactory outcomes. Biological adjuncts help accelerating tendon healing by adhering rupture ends or releasing highly complex pools of signalling factors.

Conclusion

The optimum treatment for complete rupture remains controversial. Both mini-open repair and functional protocols are attractive alternatives, while biotherapy is a potential future development.

Cite this article: X. Yang, H. Meng, Q. Quan, J. Peng, S. Lu, A. Wang. Management of acute Achilles tendon ruptures: A review. Bone Joint Res 2018;7:561–569. DOI: 10.1302/2046-3758.710.BJR-2018-0004.R2.

A new less invasive surgical technique in the management of acute Achilles tendon rupture through limited-open procedure combined with a single-anchor and "circuit" suture technique

Background

Traditional incision repair and minimally invasive repair for acute Achilles tendon repair have limitations. This study aimed to present our series of 23 patients with acute Achilles tendon rupture that was repaired using two small incisions to assist the anchor repair of the tear and a new “circuit” suture technique.

Methods

This was a retrospective study of 23 patients with acute Achilles tendon rupture treated with the new technique at Changhai Hospital between January 2015 and December 2016 and followed up for 14–33 months. Clinical outcome was assessed using the AOFAS, Leppilahti, and Arner-Lindholm scores. Complications, range of motion (ROM), and time to return to work and light sport activity were assessed.

Results

The AOFAS score was 85–96 at 3 months and 92–100 at 12 months. The 3-month ROM was 27°–37°, and the 12-month ROM was 36°–48°. The Leppilahti score was 85–95 at 3 months and 90–100 at 12 months. The recovery time of the patients was 10–18 weeks. The postoperative recovery time to exercise was 16–24 weeks. There was only one case of deep venous thrombosis. According to the Arner-Lindholm assessment criteria, patient outcomes were rated as excellent in 20 (87.0%) cases, good in three (13.0%) cases, and poor in 0 cases. The excellent-to-good rate was 100%.

Conclusion

The limited-open procedure combined with a single-anchor and “circuit” suture technique could be used to repair torn Achilles sites, with a low occurrence of complications. This new and minimally invasive technique could be an alternative in the management of acute Achilles tendon rupture.

Assessment of the Resistance of Several Suture Techniques in Human Cadaver Achilles Tendons

Many treatments are available for acute Achilles tendon ruptures, conservative and surgical, with none superior to another. For surgical treatment, one can use various techniques. Recent studies have shown that double stitches are superior to simple sutures. Therefore, in the present study, we sought to determine the suture technique that is the most resistant to rupture. We performed an experimental anatomic study with 27 fresh-frozen human cadaveric Achilles tendons obtained through the body donation program of the University of Barcelona, testing the maximum strength. We simulated a rupture by performing resection in the middle portion of the tendon, 4 cm proximal to the calcaneus insertion. We then evaluated the double Kessler, double Bunnell, Krackow, and percutaneous Ma and Griffith technique. We used absorbable suture (polydioxanone no. 1) with all the techniques. Traction was performed using a machine that pulls the tendon at 10 to 100 N in 1000 repetitive cycles. Statistical analysis was performed using the χ² test and analysis of variance, with the 95% confidence intervals (p < .05). All repairs failed at the site of the suture knots, with none pulling out through the substance of the tendon. We found no significant differences among the different open suture techniques (p > .05). The Krackow suture presented with superior resistance, with a rupture rate 16.70% but with a mean elongation of 7.11 mm. The double Bunnell suture had the same rupture rate as the Krakow suture (16.70%) but with an inferior mean elongation of 4.53 mm. The Krackow and Bunnell suture were superior in endurance, strength of failure, and primary stability compared with the other suture types. However, the former presented with greater tendon elongation, although the difference was not statistically significant. Therefore, according to our findings and the published data, we recommend double Bunnell sutures for the surgical treatment of acute Achilles tendon rupture.

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.

[Preliminary effectiveness of laminated bevel suturing technique for treating acute closed Achilles tendon rupture]

Objective

To introduce a modified technique for treating acute closed Achilles tendon rupture and evaluate the preliminary effectiveness.

Methods

Between March 2011 and September 2015, 8 cases (8 sides) with acute closed Achilles tendon rupture were repaired with the laminated bevel suturing technique. All of the patients were male with an average age of 39.3 years (range, 22-58 years), injured in nonprofessional sports. The diagnosis was confirmed by typical signs of positive heel-lift test and Thompson test; the complete rupture of Achilles tendon was determined by color Doppler ultrasound or MRI, and the distance between the stump and calcaneus was 2-5 cm (mean, 3.3 cm). The time from injury to operation was 2-12 days (mean, 4.1 days). With the patient in prone position, a posterior longitudinal incision medial to the tendon was made, the broken stumps of Achilles tendon were divided into 3 layers on the coronal plane, fibers made into strips. The strips were staggered and stacked, stitched side to side with absorbable suture. The ankle joint at the plantar flexion position was fixed with plaster, and early rehabilitation exercise was carried out.

Results

The operation time was 70-135 minutes (mean, 99 minutes); the intraoperative blood loss was 5-30 mL (mean, 15.6 mL). All the incisions healed by first intention without infection, except for 1 case who need dressing exchange because of partial delayed healing. All the patients were followed up 6-50 months (mean, 30.5 months). There was no complication of surgical site infection, sural nerve injury, or deep vein thrombosis. The patients could walk normally with powerful raising heels and return to previous sports, without complication of re-rupture. Compared with the contralateral side, the activity of ankle joint dorsiflexion reduced 0-6° (mean, 3°); plantar flexion reduced 1-5° (mean, 2°). At last follow-up, according to Arner-Lindholm score, the surgical results were excellent in 7 cases and good in 1 case, with an excellent and good rate of 100%.

Conclusion

Laminated bevel suturing technique is simple for repairing acute closed Achilles tendon rupture without the need of special surgical instruments. It provides enough tensile strength for early rehabilitation exercise to rapid and good recovery.

Biomechanical properties of different techniques used in vitro for suturing mid-substance Achilles tendon ruptures

BACKGROUND

The Dresden technique preserves the paratenon during Achilles tendon repair and may improve the plantarflexor mechanism when combined with mobilization during early rehabilitation. However, the surgical repair design for Achilles tendon ruptures can affect rates of re-rupture or lengthening. Therefore, the aim of this study was to determine the biomechanical properties of the Krackow, Double-Kessler, Double-Dresden, and Triple-Dresden techniques used for repairing mid-substance Achilles tendon ruptures during cyclical and maximum traction.

METHODS

Sixty mid-substance bovine tendons repaired after transverse rupturing were divided randomly into four groups by repair technique: Krackow, Double-Kessler, Double-Dresden, and Triple-Dresden. Cyclical tractions of 4.7, 5.8, 7.9, and 11.7mm (equivalent to 5°, 8°, 10°, and 15° of dorsal flexion, respectively) were applied to determine gapping, tensile strength, nominal suture stress, repair deformation, and specimens with clinical failure (gap>5mm). Maximal traction was applied to measure maximum strength and failure type (i.e. suture, knot, or tendon).

FINDINGS

The Triple-Dresden technique resulted in decreased gapping, nominal suture stress, repair deformation, and quantity of specimens with clinical failure as compared to the other techniques. Furthermore, Triple-Dresden tendons showed greater comparative tensile and maximum strength. During maximal traction testing, this technique presented tendon failure, whereas the Krackow, Double-Kessler, and Double-Dresden techniques had suture failures.

INTERPRETATION

Triple-Dresden repair results in better cyclical and maximum traction strengths, suggesting that this technique might be more appropriate when performing early mobilization after mid-substance Achilles tendon rupture repair.

5-year results of the 1.5cm incision Achilles tendon repair

BACKGROUND

To study a hypothesis that the cost-effective 1.5cm medial incision Achilles tendon repair technique will provide good functional outcomes which are maintained for over 5 years.

METHOD

Prospective study of 12 consecutive cases with a minimal 5-year follow-up were recruited from April 2008 to November 2010. Cases whom were mentally incompetent or those which required concomitant procedures were excluded. Outcomes measures included the numeric pain rating scale, motor power strength, range of motion, functional scoring using the AOFAS hindfoot score and patient's self-assessment using the Foot and Ankle Outcome Score (FAOS).

RESULT

No re-ruptures or sural nerve injured were identified after a minimal 5-year follow-up. Pain was minimal at 0.5/10, calf power was 5/5 and ankle range was good (plantarflexion: 38°/dorsiflexion: 21°). The AOFAS hindfoot score was 97.4 and all 5 sub-categories of the Foot and Ankle Outcome Score (FAOS) were good.

CONCLUSION

The 1.5cm medial incision repair of the Achilles tendon is an economically sound surgical technique, with minimal complications, which gives good medium length functional outcomes.

LEVEL OF EVIDENCE

IV.

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.

Efficacy of repair techniques of the Achilles tendon: A meta-analysis of human cadaveric biomechanical studies

PURPOSE

Achilles injuries are very common, mainly among young athletes. When indicated, the surgical treatment aims for strong repairs that can resist distraction and consequently ruptures. The majority of the published clinical meta-analyses reported comparisons between broad treatment modalities such as conservative treatment, open, and minimally invasive surgery.

METHODS

A meta-analysis has been conducted to assess further clinical and biomechanical variables on human cadavers related to the efficacy of Achilles repair. A total of 26 studies with 596 legs met the inclusion criteria. The maximal load to failure was set as the primary outcome. Eleven studies were amenable to meta-analysis.

RESULTS

In the reinsertion group, the analysis of the single row vs. double row subgroup showed a significantly higher strength for the latter (1.27, 95% CI=0.748-1.806, I²=81%, P<0.0001). In the mid-tendon repair group, the Achillon vs. Krackow sutures and the Bunnell vs. Krackow sutures subgroups showed no difference while the Bunnell and Krakow sutures were significantly stronger than the Kessler sutures (0.96, 95% CI=0.510-1.405, I²=63.3%, P<0.0001 and 1.37, 95% CI=2.286-0.468, I²=83.4%, P=0.003; respectively).

CONCLUSIONS

The assessment of heterogeneity located variables such as age, suture/material type, number of strands, type of testing machine and software, preloading, ankle position and loading type as potential confounders. The results of this meta-analysis are likely to have a significant impact in clinical practice.

Impact of cyclic mechanical stimulation on the expression of extracellular matrix proteins in human primary rotator cuff fibroblasts

PURPOSE

Mechanical stimulation plays an important role in the development and remodelling of tendons. The aim of the study was to evaluate the effects of mechanical stimulation on the expression of extracellular matrix proteins in human primary rotator cuff (RC) fibroblasts.

METHODS

RC fibroblasts were isolated from patients with degenerative RC tears and characterized using flow cytometry and immunohistochemistry. Cells were stimulated using the Flexcell FX5K™ Tension System. The stimulation regime was a uniaxial sinusoidal waveform with 10 % elongation and a frequency of 0.5 Hz, whereby each cycle consists of 10-s strain and 30-s relaxation. Data were normalized to mechanically unstimulated control groups for every experimental condition. RT-qPCR was performed to determine relative mRNA levels, and collagen production was measured by a colorimetric assay.

RESULTS

The positive expression of CD91 and CD10, and negativity for CD45 and CD4 confirmed the fibroblast phenotype of RC primary cells. RT-qPCR revealed that 10 % continuous cyclic strain for 7 and 14 days induced a significant increase in the mRNA expression both on the matrix metalloproteinases MMP1, MMP3, MMP13, and MMP14 and on the extracellular matrix proteins decorin, tenascin-C, and scleraxis. Furthermore, mechanically stimulated groups produced significantly higher amounts of total collagen.

CONCLUSION

These results may contribute to a better understanding of strain-induced tendon remodelling and will form the basis for the correct choice of applied force in rehabilitation after orthopaedic surgery. These findings underline the fact that early passive motion of the joint in order to induce remodelling of the tendon should be included within a rehabilitation protocol for rotator cuff repair.

Is the Dresden technique a mechanical design of choice suitable for the repair of middle third Achilles tendon ruptures? A biomechanical study

OBJECTIVE

To compare the mechanical failure of the Dresden technique for Achilles tendon repair with the double modified Kessler technique controlled repair technique. The maximum resistance of the two repair techniques are also compared.

MATERIAL AND METHODS

A total of 30 Achilles tendon ruptures in bovine specimens were repaired with an Ethibond(®) suture to 4.5cm from the calcaneal insertion. Each rupture was randomly distributed into one of two surgical groups. After repair, each specimen was subjected to a maximum traction test. The mechanical failure (tendon, suture, or knot) rates (proportions) were compared using the exact Fisher test (α=.05), and the maximum resistances using the Student t test (α=.05).

RESULTS

There was a difference in the proportions of mechanical failures, with the most frequent being a tendon tear in the Dresden technique, and a rupture of the suture in the Kessler technique.

DISCUSSION

The repair using the Dresden technique performed in the open mode, compared to the Kessler technique, has a more suitable mechanical design for the repair of middle third Achilles tendon ruptures on developing a higher tensile resistance in 58.7%. However, its most common mechanical failure was a tendon tear, which due to inappropriate loads could lead to lengthening of the Achilles tendon.

Minimally invasive, endoscopic Achilles tendon reconstruction using semitendinosus and gracilis tendons with Endobutton stabilization

Background

Plantaris tendon, peronus brevis tendon and flexor hallucis longus tendon augmentation, commonly used in Achilles tendon rupture, often lead to weakening of injured foot and they require the immobilization after the surgery. It is essential to develop the technique, which gives no such limitation and allows for immediate functional improvement.

Methods

We present our method of minimally invasive, endoscopic Achilles tendon reconstruction using semitendinosus and gracilis tendons with Endobutton stabilization.

Results

Posterolateral and posteromedial portals were made approximately 3 cm above the posterosuperior part of the calcaneus to clean the area of the Achilles tendon endoscopically. Then the hamstrings are harvested and prepared for the “Endobutton” system. A midline incision of the skin is performed approximately 1 cm above the posterosuperior part of the calcaneus to approach to the posterosuperior part of the calcaneus. Then under fluoroscopy the calcaneus was drilled through using K-wire. The distal end of the graft equipped with an Endobutton loop was entered into the drilled tunnel in the calcaneus. Later, 8 consecutive skin incisions are performed. Proximal ends of the graft were brought out through the native Achilles tendon reaching medial and lateral skin incisions. The final step was to transfer and tie the graft ends through the most proximal skin incision.

Conclusions

This minimally invasive, endoscopic technique allows reconstruction of the Achilles tendon using semitendinosus and gracilis tendons with Endobutton stabilization and can be used in so-called “difficult”, resistant cases as a “salvage procedure”.

An Alternative Bundle-to-Bundle Suturing Technique for Repairing Fresh Achilles Tendon Rupture

The main concern about conventional Achilles tendon repair surgical techniques is how to maintain the initial strength of the ruptured Achilles tendon through complicated suturing methods. The primary surgical problem lies in the properties of the soft tissue; the deterioration of the Achilles tendon, especially in its elasticity; and the surface lubricity of the local tissues. In the present study, we describe an innovative bundle-to-bundle suturing method that addresses these potential problems.

Bunnell or cross-lock Bunnell suture for tendon repair? Defining the biomechanical role of suture pretension

Background

Suture pretension during tendon repair is supposed to increase the resistance to gap formation. However, its effects on the Bunnell suture technique are unknown. The purpose of this study was to determine the biomechanical effects of suture pretension on the Bunnell and cross-lock Bunnell techniques for tendon repair.

Methods

Eighty porcine hindlimb tendons were randomly assigned to four different tendon repair groups: those repaired with or without suture pretension using either a simple Bunnell or cross-lock Bunnell technique. Pretension was applied as a 10 % shortening of the sutured tendon. After measuring the cross-sectional diameter at the repair site, static and cyclic biomechanical tests were conducted to evaluate the initial and 5-mm gap formation forces, elongation during cyclic loading, maximum tensile strength, and mode of failure. The suture failure mechanism was also separately assessed fluoroscopically in two tendons that were repaired with steel wire.

Results

Suture pretension was accompanied by a 10 to 15 % increase in the tendon diameter at the repair site. Therefore, suture pretension with the Bunnell and cross-lock Bunnell repair techniques noticeably increased the resistance to initial gap formation and 5-mm gap formation. The tension-free cross-lock Bunnell repair demonstrated more resistance to initial and 5-mm gap formation, less elongation, and higher maximum tensile strength than the tension-free Bunnell repair technique. The only difference between the tensioned cross-lock Bunnell and tensioned Bunnell techniques was a larger resistance to 5-mm gap formation with the cross-lock Bunnell technique. Use of the simple instead of cross-lock suture configuration led to failure by suture cut out, as demonstrated fluoroscopically.

Conclusion

Based on these results, suture pretension decreases gapping and elongation after tendon repair, and those effects are stronger when using a cross-lock, rather than a regular Bunnell suture. However, pretension causes an unfavorable increase in the tendon diameter at the repair site, which may adversely affect wound healing.

Long-term biomechanical outcomes after Achilles tendon ruptures

PURPOSE

The ideal treatment for Achilles tendon ruptures is still unknown. Biomechanical were correlated to radiological and clinical parameters to study outcomes.

METHODS

In this retrospective, assessor-blinded multi-centre cohort study, 52 patients with unilateral Achilles tendon rupture were assessed, each at least 3 years after injury. Patients underwent open surgery, percutaneous surgery or non-surgical treatment of Achilles tendon rupture. Both legs underwent plantar pressure distribution and isokinetic measures. Demographic parameters, maximum calf circumference (MCC) and clinical scores (American Orthopaedic Foot and Ankle Society, Achilles tendon rupture score, Hannover) were also evaluated. Complications were not assessed.

RESULTS

Peak plantar flexion torque (PPFT) was significantly weaker on the treated side compared to the untreated leg [80.4 ± 29.7 Nm (mean ± SD) vs. 92.1 ± 27.4 Nm, p < 0.0001]. PPFT and push-off force (POFF) were not different between treatment groups nor was there a leg difference in POFF alone. There was only a weak correlation of clinical scores and PPFT or POFF, respectively. MCC correlated significantly with both PPFT (R (2) = 0.21, p = 0.01) and POFF (R (2) = 0.29, p < 0.0001). POFF appeared to be a predictor of PPFT (R (2) = 0.31, p < 0.0001). Open surgery outperformed non-surgical treatment in terms of centre-of-pressure line (p = 0.007), torque per muscle volume (p = 0.04) and relative POFF per body weight (p = 0.02) and relative in side comparison (p = 0.03).

CONCLUSIONS

Clinical scores do not predict biomechanical outcomes. Clinically measured MCC is a good predictor of PPFT and POFF and can easily be used in clinical practice. Relative POFF in side comparison as well as per body weight favours surgical treatment.

Is percutaneous suturing superior to open fibrin gluing in acute Achilles tendon rupture?

PURPOSE

Open fibrin gluing is reported to enable anatomical reconstruction with less soft tissue compromise than suture repair. Our main objective was to compare the complication rate, function, pain and disability of the two operative approaches of percutaneous suture using the Paessler technique and open fibrin gluing.

METHODS

Sixty-four patients (two centres, retrospective cohort study, 2000-2009) who had undergone acute Achilles tendon repair with either percutaneous suture (n = 27; 44 years) or open fibrin glue (n = 37; 45 years) took part in a follow-up examination after a median of 63 months (range, six to 180). Ankle range of motion, calf and ankle circumferences and return to work and sports activities were evaluated. Isokinetic und sonographic evaluation results were retrieved.

RESULTS

Complications were noted in 22 patients (34 %). Delayed wound healing without evidence of surgical site infection was found in three patients in the fibrin group and two patients in the suture group. Postoperative scar tenderness described as pain at the rim of the shoe was significantly more frequent in the suture group (p = 0.03). Re-rupture requiring re-operation occurred in one patient. Transient paresthesia of the heel occurred in 12 patients. No sural nerve lesions were reported. There was no significant difference between groups regarding lower leg circumference, disability, or function. Ultrasound and isokinetic measurements did not reveal a significant difference between the two methods.

CONCLUSIONS

The present study suggests that open fibrin gluing is a reasonable alternative to percutaneous repair of acute ruptures of the Achilles tendon and both techniques can yield reliably good results.

Accelerated rehabilitation following Achilles tendon repair after acute rupture - Development of an evidence-based treatment protocol

The acute rupture of the Achilles tendon is a protracted injury. Surgery is only the beginning of a long rehabilitation period. Therefore, the rehabilitation protocol is an integral aspect to restore the pre-injury activity level. Despite several trials available comparing different treatment regimes, there is still no consensus regarding the optimal protocol. Consequently, the aim of our study was to systematically search the evidence available and define a precise rehabilitation programme after operative repair of acute Achilles tendon rupture based on the trials with the highest level of evidence. We performed a systematic literature search in Medline, Embase and Cochrane library. We identified twelve randomized controlled trials comparing different treatment regimes after operative repair of the Achilles tendon. Five trials compared full to non weight bearing, all applying immobilization in equinus. Immediate full weight bearing led to significant higher patient satisfaction, earlier ambulation and return to pre-injury activity. Four trials compared early ankle mobilization to immobilization. All trials found mobilization to be superior as it shortens time to return to work and sports significantly. Three trials compared the combination of full weight bearing and early ankle mobilization to immobilization. This combination was most beneficial. Patients showed significantly higher satisfaction, less use of rehabilitation resources, earlier return to pre-injury activities and further demonstrated significantly increased calf muscle strength, reduced atrophy and tendon elongation. No study found an increased rerupture rate for the more progressive treatment. In conclusion, the rehabilitation protocol after Achilles tendon repair should allow immediate full weight bearing. After the second postoperative week controlled ankle mobilization by free plantar flexion and limited dorsiflexion at 0° should be applied.

Biomechanical evaluation of a knotless barbed suture repair in a human Achilles tendon rupture model

BACKGROUND

Knotless barbed sutures are seeing more common use in wound closures and small tendon repairs. The purpose of this study was to evaluate the strength and resistance to gap formation of these sutures in larger tendons, such as the Achilles, compared with conventional repair.

METHODS

Six matched pairs of fresh-frozen human cadaver Achilles tendons were transected to simulate a rupture. Six tendons were repaired using a double Bunnell over-the-top technique with Fiberwire, and the matched pairs were repaired using a double Bunnell knotless technique with barbed suture. The tendons were tested to failure and stiffness, peak failure load, percentage elongation, load at initial gap and load at 5-mm gap (clinical failure) were compared.

RESULTS

The mean peak failure load for the Fiberwire group (459 N) was significantly higher (P = .029) compared with the barbed suture group (184 N). Percentage elongation at peak load was significantly lower in the barbed suture group (P = .014), as was percentage elongation at initial gapping (P = .007) and percent elongation at 5 mm of gapping (P = .004).

CONCLUSION

While the knotless barbed suture is attractive for its design and resistance to gap formation, low failure loads compared with conventional suture are concerning for large tendon repairs.

LEVELS OF EVIDENCE

Therapeutic, Level IV: Bench testing.

Effect of platelet-rich plasma on the biologic activity of the human rotator-cuff fibroblasts: A controlled in vitro study

To assess the in vitro effect of platelet-rich plasma (PRP) on biological activity of the human rotator cuff fibroblasts and to describe the optimal dose-response to maximize cellular stimulation while reducing potential risk. Rotator cuff (RC) fibroblasts of n = 6 patients (mean age of 65.2 years) undergoing arthroscopic cuff tear reconstruction were cultured in vitro for 21 days and stimulated with PRP in three different concentrations (1-, 5-, and 10-fold). Samples were obtained for DNA and GAG measurement at 1, 7, 14, and 21 days. The biological outcomes were regressed on the PRP concentration. The application of PRP significantly influenced the fibroblast proliferation and activity of the human rotator cuff with elevated glycosaminoglycan (GAG) and DNA levels. The dosage of PRP had the significantly highest impact on this proliferation using a onefold or fivefold application. PRP has a significant effect on fibroblast proliferation of the human rotator cuff in vitro with an optimal benefit using a onefold or fivefold PRP concentration. This study justifies further in vivo investigations using PRP at the human rotator cuff.

Biomechanical properties of double- and single-row suture anchor repair for surgical treatment of insertional Achilles tendinopathy

BACKGROUND

Because of intratendinous ossifications, retrocalcaneal bursitis, or intratendinous necrosis commonly found in insertional tendinosis, it is often necessary to detach the tendon partially or entirely from its tendon-to-bone junction.

HYPOTHESIS

Double-row repair for insertional Achilles tendinopathy will generate an increased contact area and demonstrate higher biomechanical stability.

STUDY DESIGN

Controlled laboratory study.

METHODS

Eighteen cadaver Achilles tendons were split longitudinally and detached, exposing the calcaneus; an ostectomy was performed and the tendon was reattached to the calcaneus in 1 of 2 ways: 2 suture anchors (single row) or a 4-anchor (double row) construct. Footprint area measurements over time, displacement after cyclic loading (2000 cycles), and final load to failure were measured.

RESULTS

The double-row refixation technique was statistically superior to the single-row technique in footprint area measurement initially and 5 minutes after repair (P = .009 and P = .01, respectively) but not after 24 hours (P = .713). The double-row construct demonstrated significantly improved measures for peak load (433.9 ± 84.3 N vs 212.0 ± 49.7 N; P = .042), load at yield (354.7 ± 106.2 N vs 198.7 ± 39.5 N; P = .01), and slope (51.8 ± 9.9 N/mm vs 66.7 ± 16.2 N/mm; P = .021). Cyclic loading did not demonstrate significant differences between the 2 constructs.

CONCLUSION

Double-row construct for reinsertion of a completely detached Achilles tendon using proximal and distal rows resulted in significantly larger contact area initially and 5 minutes after repair and led to significantly higher peak load to failure on destructive testing.

CLINICAL RELEVANCE

In treatment for insertional Achilles tendinosis, the tendon often has to be detached and anatomically reattached to its insertion at the calcaneus. To our knowledge there is a lack of biomechanical studies supporting either a number or a pattern of suture anchor fixation. Because the stresses going across the insertion site of the Achilles tendon are significant during rehabilitation and weightbearing activities, it is imperative to have a strong construct that allows satisfactory healing during the early postoperative process.

Long-term outcomes of muscle volume and Achilles tendon length after Achilles tendon ruptures

PURPOSE

The best treatment for Achilles tendon (AT) ruptures remains controversial. Long-term follow-up with radiological and clinical measurements is needed.

METHODS

In this retrospective multicentre cohort study, patients (n = 52) were assessed at a mean of 91 months follow-up after unilateral AT rupture treated by open, percutaneous or conservative (non-surgical) treatment. Demographic parameters, time off work, maximum calf circumference and clinical scores (ATRS, Hannover, AOFAS) were evaluated. Muscle volume and cross-sectional area of the calf and AT length were measured on MR images and were compared between groups and to each patient's healthy contralateral leg.

RESULTS

Reduced muscle volume was found across all groups with a higher muscle volume in the conservative (729.9 ± 130.3 cm(3)) compared to the percutaneous group (675.9 ± 207.4 cm(3), p = 0.04). AT length was longer in the affected leg (198.4 ± 24.1 vs. 180.6 ± 25.0 mm, p < 0.0001) without difference in subgroup analysis. Clinically measured ankle dorsiflexion showed poor correlation with AT length (R (2) = 0.07, p = 0.008). Muscle volume strongly correlated with the cross-sectional area (R (2) = 0.6, p < 0.0001) but showed a weak correlation with the Hannover score (R (2) = 0.08, p = 0.048). Maximum calf circumference correlated with muscle volume (R (2) = 0.42, p < 0.0001).

CONCLUSIONS

No significant difference between the treatment groups was found in muscle volume, AT length, clinical measures or days off work. Cross-sectional area and maximum calf circumference are cost-effective measurements and a good approximation of muscle volume and can thus be used in a clinical setting while clinical dorsiflexion should not be used.