Management of complications of flexor tendon injuries

Complications of flexor tendon repair

This article reviews and highlights complications of flexor tendon repairs. Although the outcomes of flexor tendon repairs have improved over the years, fair or poor functional outcomes are seen, especially in patients whose trauma involves multiple structures of the hand and in zone 5 with multiple tendon lacerations. Rupture of the flexor tendon after repair is no longer a major problem if current repair principles are carefully adhered to. Different degrees of adhesion formations and interphalangeal (IP) joint stiffness still occur in a few patients. Early active postoperative mobilization and use of a shorter splint with sparing of the wrist are effective measures to prevent adhesion formation and IP joint stiffness. Given the overall poor results and high rate of complications with flexor digitorum profundus (FDP) repairs in zone 1, a direct repair of the FDP tendon to any short remnant of the distal insertion with 10-strand or even stronger core suture repair is adopted by many units.

Tenolysis and Salvage Procedures

Complications in flexor tendon repair are common and include tendon rupture, adhesion formation, and joint contracture. Risk factors include preexisting conditions, gross contamination, concurrent fracture, early unplanned loading of the repaired tendon, premature cessation of splinting, and aggressive early active range of motion protocols with insufficient repair strength. Rupture of a repaired tendon should be followed by early operative exploration, debridement, and revision with a four-core strand suture and nonbraided epitendinous suture. Wide-awake flexor tenolysis should be considered when adhesion formation results in the plateaued range of motion, and passive motion exceeds active motion. Two-staged reconstruction is recommended when injury results in excessive scaring, joint contracture, or an incompetent pulley apparatus.

Pediatric hand ultrasound: common indications, injury, inflammation and masses

Ultrasound is a uniquely valuable tool for evaluating musculoskeletal problems in the pediatric hand. Acute and chronic injuries involving tendons and ligaments of the hand can be quickly assessed and can guide surgical decision-making. Using ultrasound, palpable lesions and masses can be evaluated for cystic and solid components aiding in differential diagnosis. Additionally, ultrasound provides evaluation of acute versus chronic changes of inflammatory arthritis, assessing disease severity and subclinical synovitis and serving as an adjunct to medical management. This review will cover common indications and ultrasound findings of the pediatric hand, focusing on common injuries, inflammatory arthritis and masses. Important anatomical features of the hand will be discussed as well as imaging technique and evaluation in the pediatric patient.

Wire Extrusion After Flexor Tendon Repair with a Multifilament Stainless Steel Cable-Crimp Suture System: A Case Report

CASE

We report the case of a 22-year-old man with a ruptured flexor tendon repair associated with wound drainage. The patient subsequently underwent flexor tendon revision with a multifilament stainless steel cable-crimp suture system. Two years after the revision repair, a blister ruptured over the patient's operative site, exposing the stainless steel wire from the revision repair. The wire was removed, and the patient regained full flexion.

CONCLUSIONS

As extrusion of metallic suture material from the skin represents a complication, surgeons should be prepared to recognize this rare complication and to preoperatively counsel patients as to this risk.

Dynamic exacerbation in inflammation and oxidative stress during the formation of peritendinous adhesion resulted from acute tendon injury

BACKGROUND

Peritendinous adhesion is among the common complications after tendon injury. Numerous studies have been carried out to prevent its formation, including modifications of surgical procedures, postoperative cares, application of medicines, etc. This study dynamically monitored fluctuations of inflammation, state of oxidative stress, and histopathologic changes around injured tendon to provide theoretical basis for further exploration in mechanisms of peritendinous adhesion formation.

METHODS

Eighteen mature Sprague-Dawley male rats were randomly allocated into 6 equal groups. Compared with control and sham group, every rat's right hind Achilles tendon in experimental groups was cut and repaired by the modified Kessler technique. Besides control and sham group, samples of tendon margin and serum were collected at different time points after the surgery. Content of TNF-α, IL-1β, and TGF-β were assayed in harvested serum. Reactive oxygen species (ROS) were detected, expression levels of related genes (IL-1β, IL-6, SOD1, SOD2, COL1, HIF1A) were quantified by qPCR, and various histopathological evaluations were performed.

RESULTS

Indicators (TNF-α, IL-1β, TGF-β1, ROS) were noticed to have a similar trend of significant rising 24 h after the surgery except TGF-β which was rising 72 h later. So were the expression trends of IL-1β, IL-6, SOD1, SOD2, and COL1. HIF1A, inversely correlated with SOD2, showed the progressive relief of regional tissue hypoxia. Histological evaluation showed the same tendency that fibrosis and inflammation were getting serious 48 h later after the surgery.

CONCLUSIONS

Inflammation, oxidative stress in injured tendon resulted from acute trauma, would be getting intense in 24 h. Peritendinous adhesion emerges and aggravates after 48 h. Thus, prompt efficient measures are advised to be taken after the injury as soon as possible.

A novel titanium implant surface modification by plasma electrolytic oxidation (PEO) preventing tendon adhesion

Titanium is one of the most commonly used materials for implants in trauma applications due to its low density, high corrosion resistance and biocompatibility. Nevertheless, there is still a need for improved surface modifications of Titanium, in order to change surface properties such as wettability, antibacterial properties or tissue attachment. In this study, different novel plasma electrolytic oxidation (PEO) modifications have been investigated for tendon adhesion to implants commonly used in hand surgery. Titanium samples with four different PEO modifications were prepared by varying the electrolyte composition and analyzed with regards to their surface properties. Unmodified titanium blanks and Dotize® coating served as controls. Samples were examined using scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), contact angle measuring system and analyzed for their biocompatibility and hemocompatibility (according to DIN ISO 10993-5 and 10,993-4). Finally, tendon adhesion of these specific surfaces were investigated by pull-off tests. Our findings show that surface thickness of PEO modifications was about 12-20 μm and had porous morphology. One modification demonstrated hydrophilic behavior accompanied by good biocompatibility without showing cytotoxic properties. Furthermore, no hemolytic effect and no significant influence on hemocompatibility were observed. Pull-off tests revealed a significant reduction of tendon adhesion by 64.3% (35.7% residual adhesion), compared to unmodified titanium (100%). In summary, the novel PEO-based ceramic-like porous modification for titanium surfaces might be considered a good candidate for orthopedic applications supporting a more efficient recovery.

A Modified Flexor Tendon Suture Technique Combining Kessler and Loop Lock Flexor Tendon Sutures

OBJECTIVES

In the present study, a novel single knot tenorrhaphy was developed by combining the modified Kessler flexor tendon suture (MK) with the loop lock technique.

METHODS

A total of 48 porcine flexor digitorum profundus tendons were collected and randomly divided into six groups. The tendons were transversely cut and then repaired using six different techniques, the MK method, double knot Kessler-loop lock flexor tendon suture (DK), and single knot Kessler-loop lock flexor tendon suture (SK), each in combination with the epitendinous suture (P), and the same three techniques without P. Furthermore, by performing the load-to-failure tests, the biomechanical properties and the time taken to complete a repair, for each tenorrhaphy, were assessed.

RESULTS

Compared to the MK+P method, DK+P was more improved, thereby enhancing the ultimate tensile strength. The SK+P method, which required fewer knots than DK+P, was easier to perform. Moreover, the SK+P repair increased the force at a 2-mm gap formation, while requiring lesser knots than DK+P.

CONCLUSION

As opposed to the traditional MK+P method, the SK+P method was improved and exhibited better biomechanical properties, which may facilitate early mobilization after the repair.

Oriented inner fabrication of bi-layer biomimetic tendon sheath for anti-adhesion and tendon healing

INTRODUCTION

Synthetic fibrous membranes unveil a promising field in anti-adhesion of tendons. Meanwhile, oriented nanofiber structures have been widely studied and used in the application of biomedical engineering, particularly in repairing and strengthening effects.

METHODS

In this study, a bi-layer poly(L-lactic acid) (PLLA) electrospun membrane was fabricated, in which the inner oriented fibrous layer was designed to promote tendon healing while outer random aligned layer was designed to prevent peritendinous adhesion.

RESULTS

It was found that fibroblasts were aligned along the oriented fiber of membranes in vitro and in a Leghorn chicken model. In biomechanical tests of repaired tendons, no significant difference was found between oriented fibrous membrane and blank control in maximum tensile strength; both oriented fibrous membranes and random fibrous membranes showed lower work of flexion than blank control, which was consistent with gross assessment.

CONCLUSION

It was practicable to promote tendon healing while preventing adhesion via bi-layer PLLA membranes with an inner-oriented-fiber fabricated structure.

Improving Strength and Quality of Epitendinous Repairs

Background: Epitendinous sutures not only join the 2 severed tendon edges but also supply strength and support to the repair. Multiple techniques have been described, but none of them include another thread of suture. This could potentially increase the strength of the repair without affecting gliding. Methods: Caprine tendons were harvested, transected, and sutured with 6-0 Prolene. Four groups were created: single thread running (SR), single thread locking (SL), double thread running (DR), and double thread locking (DL). An Instron 5542 was used to pull the repaired tendons apart, and the energy at the break was calculated (gf/mm). For gliding resistance, we harvested a human A2 pulley. A pre- and postrepair value was obtained, and a ratio was elaborated. A single-factor analysis of variance and independent sample t tests were performed. Results: The SR group had a mean energy at break of 9339.71 ± 1630.212 gf/mm; the SL group, 9629.96 ± 1476.45 gf/mm; and the DR group, 9600.221 ± 976.087 gf/mm, with no statistical significance. The DL group was significantly higher at 14 740.664 ± 2596.586 gf/mm (P < .05). When comparing SR with DL for gliding, SR had less than half of the resistance than DL (0.018 ± 0.004 and 0.049 ± 0.015 N/mm, respectively), with statistical significance (P < .05). Conclusion: Using a single suture thread for running epitendinous repair is no different than locking with a single thread or using an extra thread in a running fashion. Performing a double suture thread with a locking technique is significantly stronger than the previously mentioned repairs, with the disadvantage of more resistance at the pulley.

Pathomechanics and Management of Secondary Complications Associated with Tendon Adhesions Following Flexor Tendon Repair in Zone II

Despite the number of rehabilitation strategies and guidelines developed to maximize the gliding amplitude of repaired tendons, secondary complications, such as decreased range of motion and stiffness associated with tendon adhesions, commonly arise. If left untreated, these early complications may lead to secondary pathomechanical changes resulting in fixed deformities and decreased function. Therefore, an appropriate treatment regimen must not only include strategies to maintain the integrity of the repaired tendon, but must also avoid secondary complications due to reduced gliding amplitude. This review presents a biomechanical analysis of the dynamics of tendon gliding following repair in zone II and rehabilitation strategies to minimize secondary complications related with tendon adhesions.

Controlled release of curcumin from curcumin-loaded nanomicelles to prevent peritendinous adhesion during Achilles tendon healing in rats

We introduced curcumin-loaded nanomicelles into a tendon-healing model to evaluate their effects on tendon healing and adhesion. Three groups consisting of 36 rats underwent rupture and repair of the Achilles tendon. The treatment group received an injection of curcumin-loaded nanomicelles (gold nanorods [GNRs]-1/curcumin in polymeric nanomicelles [curc@PMs] at a dosage of 0.44 mg curcumin/kg in 0.1 mL saline) into the surgical site and exposed to laser postoperatively at weeks 1, 2, and 3, for three times 10 seconds each, on the surgical site in the rats that underwent tendon rupture and repair, while the other two groups received 0.44 mg curcumin/kg in 0.1 mL saline and 0.1 mL of saline, respectively. The specimens were harvested at 4 weeks and subjected to biomechanical and histological evaluation. The scoring results of tendon adhesion indicated that GNRs-1/curc@PMs group was in the lowest grade of peritendinous adhesions compared to the other groups. Histological assessment further confirmed the preventive effect of GNRs-1/curc@PMs on tendon adhesion. These findings indicated greater tendon strength with less adhesion in the group treated with GNRs-1/curc@PMs combined with laser exposure, and that nanoparticle-based therapy may be applied to prevent adhesion in clinical patients.