Minimally invasive versus open surgery for acute Achilles tendon rupture: a systematic review

Minimally invasive versus open surgery for acute Achilles tendon rupture: a systematic review of overlapping meta-analyses

Background

A number of meta-analyses have been carried out to evaluate the effects of minimally invasive surgery (MIS) versus open surgery (OS) for acute Achilles tendon rupture. However, discordant findings were seen in these meta-analyses. The present study, performing a systematic review of overlapping meta-analyses regarding MIS versus OS of acute Achilles tendon rupture, aimed to assist decision-makers interpret and choose among conflicting meta-analyses, as well as to offer treatment recommendations based on current best evidence.

Methods

The literature search was performed to identify systematic reviews comparing MIS with OS for Achilles tendon rupture. Meta-analyses only comprising randomized controlled trials (RCTs) were included. Two authors individually evaluated the quality of meta-analysis and extracted data. The Jadad decision algorithm was conducted to ascertain which meta-analysis offered the best evidence.

Results

A total of four meta-analyses was included. All these meta-analyses comprised RCTs or quasi-RCTs and were determined as Level-II evidence. The scores of the Assessment of Multiple Systematic Reviews (AMSTAR) ranged from 7 to 10 (median 9.5). The Jadad algorithm indicated that the best meta-analysis should be chosen according to the search strategies and application of selection. A high-quality meta-analysis with more RCTs was chosen, which suggested that there was no statistically significant difference between MIS and OS regarding rerupture rate, tissue adhesion, sural nerve injury, deep infection, and deep vein thrombosis. However, MIS could decrease superficial infection rate, and had a better patient satisfaction for good to excellent outcomes in comparison to OS.

Conclusions

Based on the best available evidence, MIS may be superior to OS for treating acute Achilles tendon rupture. However, due to some limitations, this should be cautiously interpreted, and further high-quality studies are needed.

Achilles Tendon Repair in Obese Patients Is Associated With Increased Complication Rates

Objective The objective of the present study is to utilize a national database to examine the association between obesity and postoperative complications after primary Achilles tendon repair. Methods The PearlDiver database was queried for patients undergoing primary Achilles repair using CPT 27650. Excision of a Haglund's deformity or tendon transfer were exclusion criteria. Patients were then divided into obese (body mass index [BMI] > 30 kg/m(2)) and nonobese (BMI < 30 kg/m(2)) cohorts using ICD-9 codes. Complications within 90 days postoperatively were assessed using ICD-9 and CPT codes. Results In all, 18 948 patients who underwent primary Achilles tendon repair were identified from 2005 to 2012. Overall, 2962 patients (15.6%) were coded as obese or morbidly obese. Obese patients had significantly higher rates of postoperative wound complications (odds ratio [OR] = 2.1; P < .0001), infection (OR = 1.8; P < .0001), venous thromboembolism (VTE; OR = 1.8; P = .001), and medical complications (OR = 3.9; P < .0001) compared with nonobese patients after primary Achilles tendon repair. Additionally, obese patients had a significantly lower rate of ankle stiffnesassociated with a significantly higher risk of s (OR = 0.4; P < .0001) compared with nonobese patients. Conclusion Obesity is associated with a significantly higher risk of wound complications, infection, VTE, and medical complications after primary Achilles tendon repair.

LEVELS OF EVIDENCE

Prognostic, Level II: Retrospective study.

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.

The structural and mechanical properties of the Achilles tendon 2 years after surgical repair

BACKGROUND

Acute ruptures of the Achilles tendon affect the tendon's structural and mechanical properties. The long-term effects of surgical repair on these properties remain unclear.

PURPOSE

To evaluate effects of early mobilization versus traditional immobilization rehabilitation programs 2 years after surgical Achilles tendon repair, by comparing force-elongation and stress-strain relationships of the injured tendon to those of the uninjured tendon.

METHODS

A group of males with previous Achilles tendon rupture (n=18) and a group of healthy male controls (n=9) participated. Achilles tendon rupture group consisted of patients that had received early mobilization (n=9) and patients that had received traditional immobilization with a plaster cast (n=9). Comparisons of tendon structural and mechanical properties were made between Achilles tendon rupture and healthy control groups, and between the uninjured and injured sides of the two rehabilitation groups in Achilles tendon rupture group. Ultrasound was used to determine bilaterally tendon cross-sectional area, tendon resting length, and tendon elongation as a function of torque during maximal voluntary plantar flexion. From these data, Achilles tendon force-elongation and stress-strain relationships were determined.

FINDINGS

The Achilles tendon rupture group uninjured side was not different from healthy control group. Structural and mechanical parameters of the injured side were not different between the Achilles tendon rupture early mobilization and the immobilization groups. Compared to the uninjured side, the injured side showed a reduction in stress at maximal voluntary force, in Young's modulus and in stiffness.

INTERPRETATION

Two years post-surgical repair, the Achilles tendon mechanical properties had not returned to the uninjured contralateral tendon values.

Informing tendon tissue engineering with embryonic development

Tendon is a strong connective tissue that transduces muscle-generated forces into skeletal motion. In fulfilling this role, tendons are subjected to repeated mechanical loading and high stress, which may result in injury. Tissue engineering with stem cells offers the potential to replace injured/damaged tissue with healthy, new living tissue. Critical to tendon tissue engineering is the induction and guidance of stem cells towards the tendon phenotype. Typical strategies have relied on adult tissue homeostatic and healing factors to influence stem cell differentiation, but have yet to achieve tissue regeneration. A novel paradigm is to use embryonic developmental factors as cues to promote tendon regeneration. Embryonic tendon progenitor cell differentiation in vivo is regulated by a combination of mechanical and chemical factors. We propose that these cues will guide stem cells to recapitulate critical aspects of tenogenesis and effectively direct the cells to differentiate and regenerate new tendon. Here, we review recent efforts to identify mechanical and chemical factors of embryonic tendon development to guide stem/progenitor cell differentiation toward new tendon formation, and discuss the role this work may have in the future of tendon tissue engineering.