Flexor Tendon Injuries

Biomechanical evaluation of the ST-knot: A new suture for flexor tendon repair

PURPOSE

Although tendon lacerations are common, there is currently no consensus on choice of suture. Easy and fast sutures that impart enough strength to allow mobilization are needed. This study compared the ex vivo biomechanical strength (force required to create a 2 mm tendon gap) of a novel suture (ST-knot) with that of a conventional suture (double Kessler).

MATERIALS AND METHODS

Forty fresh deep flexor tendons from porcine forelimbs were used. Both repaired tendon ends were mounted on standard traction jaws of an axial traction machine at an initial distance of 40 mm for all tendons. A high-definition camera was used to determine the force forming a 2 mm gap. Ten tendons in group 1 (ST-knot) and 10 in group 2 (double Kessler) were prepared with PDS 4.0 (single thread for Kessler, double thread for ST-knot). Tendons in groups 3 (ST-knot) and 4 (double Kessler) were repaired with PDS 1.0 using the same principle.

RESULTS

There was no significant difference in the force required to form a 2 mm tendon gap between groups 1 and 2, and this trend was identical when using a stronger thread in groups 3 and 4. The maximum force before rupture, mode of repair failure, stress and stiffness were also comparable, with no significant differences between groups 1 and 2, or between groups 3 and 4.

CONCLUSIONS

The ST-knot showed comparable results to the double-Kessler knot, whichever the thread used. Because it involves fewer steps than conventional techniques and is easy to perform, the ST-knot may offer a therapeutic solution, particularly in complex trauma with multiple tendon injury.

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.

Short-Term and Long-Term Therapeutic Results of Deep Flexor Tendon Repair in Zone II in Patients Referred to Imam Khomeini Hospital, Ahvaz, Southern Iran

Background

Hand injury as an important concern for the surgeon and the patient requires proper and timely treatment to prevent complications such as infection and adhesions, and with a proper rehabilitation program, the patient returns to maximum function as soon as possible. We aimed to investigate the short-term and long-term treatment results of deep flexor tendon repair in in zone II.

Methods

This retrospective study was performed on 34 patients with 45 injured fingers in the zone II referred to Ahvaz Imam Khomeini Hospital, Ahvaz, Iran during 2017-2019. The results of deep flexor tendons repair in two groups, immediate and delayed primary repair were assessed.

Results

The mean age of the patients was 27.76 years. There was no significant remarkable between male and female in the incidence of complications such as infection, tendon rupture and adhesions. 29.4% (n=10) had poor outcome, 8.8% (n=3) had fair outcome, 29.4% (n=10) had good outcome and 32.4% (n=11) had excellent outcomes. 26.5% had adhesion and infection rate was 11.8%.

Conclusion

Among surgeons, there is consensus for the primary repair of tendon injury, but there was no significant difference between the results of immediate and delayed primary repair. Although physiotherapy has been suggested as an effective factor in improving hand function, its positive effect on the range of motion of the fingers has not been proven.

Distal forearm squeeze test for the diagnosis of digital flexor tendon injuries

BACKGROUND

The forearm/wrist squeeze/compression test has been used to examine digital flexor tendon injuries with varied names. Furthermore, the test has not been minutely described and its mechanism remains unclear. We renamed the test the "distal forearm squeeze test". The purpose of this study was to elaborate on the test and elucidate the mechanism.

METHODS

Two patients with digital flexor tendons ruptured in zone 3 and zone 1 respectively and 50 outpatients with intact digital tendons underwent the test. Then the test was performed on 3 chickens under 4 conditions. First, when the digital flexor and extensor tendons were all intact. Second, after the flexor tendons of the third toe were transected. Third, after the flexor tendons of all toes of the foot were transected. Finally, after the flexor and extensor tendons of all toes of the foot were transected.

RESULTS

In the patient with digital flexor tendons ruptured in zone 3, the test showed that the injured digit was flexed slightly while the uninjured digits were flexed obviously. In the patient with digital flexor tendon ruptured in zone 1, after separate stabilization of the proximal interphalangeal (PIP) joints of the injured and uninjured fingers in extension, the test showed that the distal interphalangeal joint of the patient's injured finger had no response, while those of the uninjured fingers were flexed. All 50 subjects showed clenched or half-clenched hands in response to the test. The test showed that all toes were flexed when the digital tendons of the chicken were intact. All toes were flexed except the third toe after the flexor tendons of the third toe were transected. All toes were extended after all the digital flexor tendons were transected. All toes had no response after all the digital flexor and extensor tendons were transected.

CONCLUSIONS

The distal forearm squeeze test is valuable in examining digital flexor tendon injuries. If only the flexor digitorum profundus tendon is examined, the PIP joint of the finger should be stabilized in extension during the test.

Healing strength of tendon repair with or without knots between two tendon ends and histological changes in a chicken model

We studied the healing strength and histological changes of digital flexor tendons repaired using Kessler (core suture knots placed over the tendon surface) and modified Kessler (core suture knots placed between two tendon ends) in 31 long toes of chicken. Four weeks after surgery, the healing tendons were measured in a tensile testing machine, and the adhesion formation and histological changes were observed. The strength of the Kessler repairs was significantly greater than that of the modified Kessler repairs with a 35% mean difference. No significant difference was found between the adhesion scores of the tendons repaired with both techniques. In histological sections, the arrangement of collagen fibers in the modified Kessler repair group was more disordered. We conclude that the tendons repaired with the Kessler method are stronger than those with the modified Kessler technique. The knots between tendon ends are detrimental to the early healing strength of digital flexor tendons.

Alternate Graft Options for Staged Flexor Tendon Reconstruction: A Cadaveric Study of Hamstring Autografts Compared to Conventional Autografts

PURPOSE

To compare the semitendinosus and gracilis tendon lengths and diameters to the palmaris longus, plantaris, flexor digitorum profundus, and flexor pollicis longus (FPL) tendons in a cadaveric model to evaluate the feasibility of hamstring autograft use for staged flexor tendon reconstruction.

METHODS

Fifteen fresh cadavers were evaluated for surgical incisions about the knee, forearm, and hand. All flexor digitorum profundus (FDP), FPL, palmaris longus, plantaris, semitendinosus, and gracilis tendons were harvested from each specimen. Diameter and length were recorded and means with SDs were calculated. The mean diameters of the gracilis and semitendinosus were compared to the mean diameters of the FDP and FPL tendons. The hamstring tendon lengths were then compared in terms of percentage of the palmaris longus and plantaris tendon lengths.

RESULTS

The gracilis (18.0 cm) and semitendinosus (19.9 cm) means were notably longer than the palmaris longus (16.0 cm) and shorter than the plantaris (30.0 cm). The average gracilis tendon diameter (3.8 mm) was smaller than the flexor tendon diameters except for the little finger FDP (3.8 mm). The semitendinosus tendon diameter (4.8 mm) was larger than all flexor tendons with the exception of the middle finger FDP (4.6 mm). Average gracilis and semitendinosus tendon diameters were 3.7 mm and 4.5 mm in males, and 3.8 mm and 4.8 mm in females.

CONCLUSIONS

This study showed the gracilis tendon to have adequate length and diameter for potential autograft use in staged flexor tendon reconstruction in all digits but the little finger. The semitendinosus is larger in diameter than the native flexor tendons, making it a poor autograft option in cases with an intact pulley system.

CLINICAL RELEVANCE

Common tendon autograft options for flexor tendon reconstruction are variably present, and the use of gracilis and semitendinosus autograft present potential graft options.

Carbodiimide-Derivatized Synovial Fluid for Tendon Graft Coating Improves Long-Term Functional Outcomes of Flexor Tendon Reconstruction

BACKGROUND

Flexor digitorum profundus (FDP) tendon injury is common in hand trauma, and flexor tendon reconstruction is one of the most challenging procedures in hand surgery because of severe adhesion that exceeds 25% and hinders hand function. The surface properties of a graft from extrasynovial tendons are inferior to those of the native intrasynovial FDP tendons, which has been reported as one of the major causations. Improved surface gliding ability of the extrasynovial graft is needed. Thus, this study used carbodiimide-derivatized synovial fluid and gelatin (cd-SF-gel) to modify the surface of the graft, thus improving functional outcomes using a dog in vivo model.

METHODS

Forty FDP tendons from the second and fifth digits of 20 adult women underwent reconstruction with a peroneus longus (PL) autograft after creation of a tendon repair failure model for 6 weeks. Graft tendons were either coated with cd-SF-gel ( n = 20) or not. Animals were euthanized 24 weeks after reconstruction, and digits were collected after the animals were euthanized for biomechanical and histologic analyses.

RESULTS

Adhesion score (cd-SF-gel, 3.15 ± 1.53; control, 5 ± 1.26; P < 0.00017), normalized work of flexion (cd-SF-gel, 0.47 ± 0.28 N-mm/degree; control, 1.4 ± 1.45 N-mm/degree; P < 0.014), and distal interphalangeal joint motion (cd-SF-gel, 17.63 ± 6.77 degrees; control, 7.07 ± 12.99 degrees; P < 0.0015) in treated grafts all showed significant differences compared with nontreated grafts. However, there was no significant difference in repair conjunction strength between the two groups.

CONCLUSION

Autograft tendon surface modification with cd-SF-gel improves tendon gliding ability, reduces adhesion formation, and enhances digit function without interfering with graft-host healing.

CLINICAL RELEVANCE STATEMENT

The authors demonstrate a clinically relevant and translational technology by using the patient's own synovial fluid to "synovialize" an autologous extrasynovial tendon graft to improve functional outcomes following flexor tendon reconstruction.

Flexor Tendon Zone II Repair

Background

Flexor-tendon injury is a historically challenging problem for orthopaedic surgeons. Much research has been dedicated to finding solutions that offer balance in terms of the strength and ease of the repair versus the rate of complications such as adhesions. The number of core sutures, distance from the tendon edge, and use of an epitendinous stitch have been shown to affect repair strength1-4. A number of configurations have been described for the placement of the suture; however, none has been identified as a clear gold standard5. This article will highlight the preferred tendon repair technique of the senior author (R.J.S.), the Strickland repair with a simple running epitendinous stitch. Relevant anatomy, indications, operative technique, and postoperative management will be discussed.

Description

The flexor tendon is typically accessed via extension of the laceration that caused the initial injury. After the neurovascular structures and pulleys are assessed, the tendon is cleaned and prepared for repair. A 3-0 braided nylon suture is utilized for the 4-core strand repair and placed in the Strickland fashion. A 5-0 polypropylene suture is then utilized for the simple running epitendinous stitch.

Alternatives

Multiple alternative techniques have been described. These vary in the number of core strands, the repair configuration, the suture caliber, and the use of an epitendinous or other suture. Nonoperative treatment is typically reserved for partial flexor-tendon laceration, as complete tendon discontinuity will not heal and requires surgical intervention.

Rationale

The 4-core strand configuration has been well established to increase the strength of the repair as compared with 2-core strand configurations, while also being easier to accomplish and with less suture burden than other techniques1. The presently described technique has excellent repair strength and can allow for early active range of motion, which is critical to reduce the risk of postoperative adhesions and stiffness.

Expected Outcomes

Excellent outcomes have been demonstrated for primary flexor-tendon repair if performed soon after the injury1,2,6,7. Delayed repair may lead to adhesions and poor tendon healing8. Early postoperative rehabilitation is vital for success9. There are advocates for either active or passive protocols10-12. The protocol at our institution is to begin early active place-and-hold therapy at 3 to 5 days postoperatively, which has been shown in the literature to provide improved finger motion as compared with passive-motion therapy13-16.Important Tips:: The proximal end of the tendon may need to be retrieved via a separate incision if it is not accessible through the flexor-tendon sheath.The proximal end of the tendon may be held in place with a 25-gauge needle in order to best place sutures into both ends of the tendon.The epitendinous suture is run around the back wall before the core sutures are tied down, in order to prevent the tendon and repair from bunching up and becoming overly bulky.The entire A4 pulley and the distal A2 pulley can be divided for exposure if necessary.Up to 2 cm of the flexor-tendon sheath can be divided.If there are concomitant digital nerve injuries, repair these after the tendon, in order to avoid damaging the more delicate nerve repair while manipulating the tendon for repair.The most common major complications following tendon repair are formation of adhesions and rerupture. Acronyms and Abbreviations:: FDS = flexor digitorum superficialisFDP = flexor digitorum profundusMCP = metacarpophalangealPIP = proximal interphalangealDIP = distal interphalangeal.

Flexor Tendon Repair Techniques: M-Tang Repair

The authors present the methods and outcomes from six institutes where M-Tang repairs with early active flexion exercise are used for zone 2 digital flexor tendon repair. The authors had close to zero repair ruptures, and few digits needed tenolysis. The excellent to good results are generally between 80% and 90%. In the pandemic period, less stringent therapy supervision might have allowed some patients to move too aggressively, with repair ruptures not seen before the pandemic in one institute. In Nantong, Yixing, and Saint John, the rupture incidence is zero to 1%. In Florence and Heidelberg, the rupture incidence was 3%.

Risk factors associated with tendon adhesions after hand tendon repair

Background

Tendon adhesions after hand tendon repair are one of the most difficult complications of hand surgery and can cause severe disability. This study aimed to assess the risk factors associated with tendon adhesions after hand tendon repair to provide a theoretical foundation for the early prevention of tendon adhesions in patients with tendon injuries. Moreover, this study intends to increase doctors' awareness of the issue and serves as a reference for developing new prevention and treatment strategies.

Methods

We retrospectively analyzed 1,031 hand trauma cases that underwent repair after finger tendon injury in our department between June 2009 and June 2019. Tendon adhesions, tendon injury zones, and other relevant information were collected, summarized, and analyzed. The significance of data was determined using a t-test or Pearson's chi-square test, and odds ratios (OR) were calculated using logistic regression tests to describe factors associated with post-tendon repair adhesions.

Results

A total of 1,031 patients were enrolled in this study. There were 817 males and 214 females with an average age of 34.98 (2-82) years. The injured side included 530 left and 501 right hands. Postoperative finger tendon adhesions occurred in 118 cases (11.45%), including 98 males and 20 females, 57 left and 61 right hands. The risk factors for the total sample in the descending order were degloving injury, no functional exercise, zone II flexor tendon injury, time from injury to surgery >12 h, combined vascular injury, and multiple tendon injuries. The flexor tendon sample shared the same risk factors as the total sample. Risk factors for the extensor tendon sample were degloving injury, no functional exercise.

Conclusions

Clinicians should pay close attention to patients with tendon trauma in hand having the following risk factors: degloving injury, zone II flexor tendon injury, lack of functional exercise, time from injury to surgery >12 h, combined vascular injury, and multiple tendon injuries. Due to the high risk of post-repair adhesions in patients with the conditions mentioned above, individualized treatment measures should be designed for the risk factors, and postoperative functional exercise of the hand is required.

The Effects of the TSOL Knot on the Repair Strength and Gliding Resistance Following Flexor Tendon Repair

BACKGROUND

The stability of a suture knot construct has been realized as an important parameter that affects the strength of flexor tendon repairs. A novel 2-strand-overhand-locking (TSOL) knot, which is not commonly used in the clinical setting, recently was reported to increase repair strength and to decrease tendon gliding resistance in a 2-strand repair technique. The purpose of the present study was to investigate the effect of the TSOL knot on tendon repair strength and gliding resistance compared with a typical surgical knot in both 2-strand and 4-strand repair techniques using an in vitro turkey flexor tendon model.

METHODS

Sixty flexor digitorum profundus tendons from the long digit of the turkey foot were divided evenly into 4 groups and repaired with the following techniques: (1) a 2-strand modified Pennington repair with a square knot, (2) a 2-strand modified Pennington repair with a TSOL knot, (3) a 4-strand grasping cruciate repair with a square knot, and (4) a 4-strand grasping cruciate repair with a TSOL knot. Repaired tendons were tested for failure mode, gliding resistance, and repair strength at failure.

RESULTS

The repair strength and stiffness of the 4-strand repairs were significantly higher than those of the 2-strand repairs, regardless of knot type (p < 0.05). The repair strength at failure of the TSOL knot was significantly greater than that of the square knot in 2-strand repairs (p < 0.05) but not in 4-strand repairs. The gliding resistance of the TSOL knot was significantly decreased compared with that of the square knot in both 2-strand and 4-stand repairs (p < 0.05). With regard to failure mode, the TSOL knot was less likely to fail due to knot unravelling.

CONCLUSIONS

In this in vitro biomechanical study involving the use of turkey flexor tendons to compare gliding resistance and repair strength characteristics for knot-inside 2 and 4-strand repairs, the TSOL knot was associated with decreased repaired tendon gliding resistance, regardless of the number of strands used. Although the TSOL knot also increased the repair strength, the difference was only significant when 2-strand repairs were used. The results of our study support the use of the TSOL knot in the clinical setting of flexor tendon repair using 2 or 4-strand, knot-inside methods.

CLINICAL RELEVANCE

In surgical repair of flexor tendons, there is substantial interest in maximizing strength while minimizing friction. This study shows the potential utility of the TSOL knot to increase repair strength while decreasing gliding resistance, particularly in 2-strand repairs.

The influence of a nanoparticle gel loaded with siRNA-cyclooxygenase on flexor tendon healing: an in vivo animal study

We investigated the influence of cyclooxygenase (COX)-1 and COX-2 siRNAs delivered through a nanoparticle-gel system on the strength of flexor tendon repairs. Sixteen flexor digitorum profundus (FDP) tendons of chicken toes were transected, repaired and wrapped with gels to evaluate gel adherence. We found that the gel adhered to the tendon surface firmly. Next, 56 tendons were used in a first set of in vivo experiments to compare the therapeutic effects of different doses of COX siRNAs. Another 15 tendons were added in a second set to further assess the effects of a dosage of 12 μg. After 4 weeks, the mean strength of the repaired tendons increased most notably in the toes treated with 12 μg COX siRNAs, and the number of samples with low strength (<35 N) was significantly smaller than in the group without molecular treatment. We conclude that COX-1 and COX-2 siRNAs delivered through a nanoparticle-gel system increased the healing strength of the repaired tendons.

Comparison of Modified Kessler and McLarney Techniques in Zone II Flexor Tendon Repair

Introduction

Hand injuries are common in the routine practice of any upper limb surgeon. The laceration of the flexor tendons can engage the functional prognosis of the hand. Hence, there exist a multitude pf suturing techniques whose goal is to have a solid repair, allowing an early rehabilitation. Our study aims at comparing the functional results after flexor tendon repairs in zone II using two different techniques, modified Kessler technique and McLarney technique.

Methods

Our study included 42 patients, divided into two groups, one having benefited from the modified Kessler technique and the other from the McLarney technique. The modified Strickland classification was used to compare the functional results at six months after surgery of the two techniques.

Results

Our study showed a better post-operative functional outcome with a lower risk of post-operative rupture in patients operated with the McLarney four-strand technique compared to patients operated with the modified Kessler two-strand technique.

Conclusion

Hand wounds in zone II remain a therapeutic challenge for any orthopedic surgeon due to the multiplicity of factors involved in the prognosis, in particular the type of suture. The suture with more than two strands has proven its effectiveness and its reproducibility, making it possible to find the balance sought by the surgeon, namely a suture that is not cumbersome, easy and quick to perform, and strong enough to start early rehabilitation.

Non-Viral Delivery of Gene Therapy to the Tendon

The tendon, as a compact connective tissue, is difficult to treat after an acute laceration or chronic degeneration. Gene-based therapy is a highly efficient strategy for diverse diseases which has been increasingly applied in tendons in recent years. As technology improves by leaps and bounds, a wide variety of non-viral vectors have been manufactured that attempt to have high biosecurity and transfection efficiency, considered to be a promising treatment modality. In this review, we examine the unwanted biological barriers, the categories of applicable genes, and the introduction and comparison of non-viral vectors. We focus on lipid-based nanoparticles and polymer-based nanoparticles, differentiating between them based on their combination with diverse chemical modifications and scaffolds.

Investigations into flexor tendon repair: a research journey over three decades

In this article, I review how my team and I addressed clinical concerns in Zone 2 flexor tendon repair, and how major findings in each step of our research were translated into clinical practice. The focus of the article is on the thought processes behind each new investigation, the interpretation of research findings and conclusions drawn from the basic and clinical studies.

One Year of COVID-19: Lessons Learned in a Hand Trauma Center

2020 will be remembered worldwide as the year of COVID-19 outbreak. The onset of this pandemic abruptly changed everybody’s life and, in a particular manner, doctors’ lives. Our hand surgery department became rapidly one of the first COVID-19-specialized wards in Italy, impacting considerably the authors’ routines and activities. In this paper, the authors focus on how the demographics of patients with hand trauma changed and how they had to modify their activity. The authors retrospectively took into consideration all patients reaching their emergency department (ED) with hand trauma between 9 March 2020 (the day of the beginning of the first lockdown in Italy) and 8 March 2021 and compared them to those who reached the ED in the three previous years. Authors have analyzed the number of patients, their gender and age, the severity of their trauma, where the trauma occurred, the type of lesion, the percentage of patients who underwent surgery, and the percentage of patients who had an emergency admission. In the last year, the number of patients reaching the ED for a hand trauma has been reduced by two thirds (975 patients during the past year), the mean age of those patients has slightly increased, the severity of cases has increased, places of trauma and type of lesions have changed, and, lastly, the percentage of patients needing surgery who were admitted immediately has increased. This paper shows how the type of patients reaching the ED changed and discusses how surgeons evolved and modified their habits in treating those patients during the first lockdown and the year that followed.

Dynamic Tendon Grip (DTG™) novel knot array compared to traditional sutures for zone two flexor tendon injury - a biomechanical feasibility study

BACKGROUND

Flexor tendon injuries pose many challenges for the treating surgeon, the principal of which is creating a strong enough repair to allow early active motion, preserving a low-profile of the repair to prevent buckling and subsequent pulley venting. A main concern is that a low-profile repair is prone to gap formation and repair failure. The Dynamic Tendon Grip (DTG™) all suture staple device claims to allow a strong and low-profile repair of the flexor tendon. The purpose of this study is to test the effects of the DTG™ device in early active motion simulation on range of motion, load to failure and gap formation and to compare it to traditional suturing technique.

METHODS

Twelve fresh-frozen cadaveric fingers were assigned to two groups: DTG™ device (n = 9) and traditional suturing (double Kessler 4-core suture and a peripheral suture, n = 3). The deep flexor was incised and repaired in zone 2, and active motion simulation was carried out with a cyclic flexion-extension machine. Finger range of motion and gap formation were measured, as well as load to failure and method of repair failure.

RESULTS

Following motion simulation, ROM decreased from 244.0 ± 9.9° to 234.5 ± 5.8° for the DTG™ device compared to 234.67 ± 6.51° to 211.67 ± 10.50° for traditional suturing. The DTG™ repair demonstrated gap formation of 0.93 ± 0.18 mm in 3 of 8 specimens after applying 1 kg load, which negated after load removal. Load to failure averaged 76.51 ± 23.15 N for DTG™ and 66.31 ± 40.22 N for the traditional repair. Repair failure occurred as the suture material broke for the DTG™ array and at the knot level for the traditional repair.

CONCLUSIONS

The DTG™ all-suture stapling concept achieved a strong low-profile repair in zone 2 flexor tendon injury after active motion simulation. Further clinical studies will be needed to determine the effectiveness of this device compared to traditional techniques.

Effect of electromyographic biofeedback training on functional status in zone I-III flexor tendon injuries: a randomized controlled trial

BACKGROUND

Despite advances in hand therapy and surgery, functional deficits persist after flexor tendon repair especially in zone I-III. This suggests that methods applied may be insufficient. Electromyographic (EMG) biofeedback may provide an effective tendon gliding through visual and auditory feedback.

PURPOSE

The purpose of this study was to investigate the effect of EMG biofeedback training applied in addition to early passive motion protocol on functional status in zone I-III flexor tendon injuries.

METHODS

Patients were randomly assigned into two groups, each consisted of 11 patients. In addition to early passive motion method, EMG biofeedback training was applied in the first group. The second group was followed only with early passive motion protocol. Joint range of motion (ROM), Michigan Hand Outcomes Questionnaire (MHQ) and grip strength were evaluated.

RESULTS

There were no significant differences between the groups in terms of the ROM, MHQ scores and grip strength (p ≥ .087). However, there were clinically important differences in the results of the 12th week ROM (effect size = 0.70), 24th week activity of daily living (ADL) score in MHQ (effect size = 0.68), 12th week gross, tip pinch and lateral grip strength (effect sizes = 0.59, 0.52, 0.81, respectively) and 24th week gross, tip pinch and lateral grip strength (effect sizes = 0.69, 0.73, 0.69, respectively) between the two groups.

CONCLUSIONS

EMG biofeedback training was clinically but not statistically superior to early passive motion method in terms of the effect on functional status.

Zone II Flexor Pollicis Longus Repair: Thumb Flexion and Complications

Background: The aim of flexor pollicis longus (FPL) repair is to create a construct that is strong enough to withstand forces encountered during rehabilitation and to achieve an optimal active range of motion. The aim of this study was to: (1) assess factors influencing active thumb interphalangeal (IP) joint flexion; and (2) assess the factors associated with reoperation. Methods: Retrospectively, 104 patients with primary repair of a Zone II FPL laceration from 2000 to 2016 were identified. A medical chart review was performed to collect patient-, injury-, and surgery characteristics as well as the degree of postoperative active IP-flexion and occurrence of reoperation. Bivariate analyses were performed to identify factors influencing active IP-flexion and factors associated with reoperation. Results: The reoperation rate was 17% (n = 18) at a median of 3.4 months (range: 2.3-4.4). Indications for reoperation mainly included adhesion formation (n = 10, 56%) and re-rupture (n = 5, 28%). The median range of active IP-flexion was 30° (interquartile range [IQR]: 20-45) at a median of 12.4 weeks (IQR: 8.1-16.7). Solitary injury to the thumb (β = 17.9, P = .022) and the use of epitendinous suture (β = 10.0, P = .031) were associated with increased active IP-joint flexion. No factors were statistically associated with reoperation. Conclusions: About 1 in 5 patients undergo reoperation following primary repair of a Zone II FPL laceration, mostly within 6 months of initial surgery. The use of epitendinous suture is associated with greater active IP-flexion. Patients with multiple digits injured accompanying a Zone II FPL laceration have inferior IP-joint motion.

Flexor tendon repair: recent changes and current methods

The current clinical methods of flexor tendon repair are remarkably different from those used 20 years ago. This article starts with a review of the current methods, followed by presentation of past experience and current status of six eminent hand surgery units from four continents/regions. Many units are using, or are moving toward using, the recent strong (multi-strand) core suture method together with a simpler peripheral suture. Venting of the critical pulleys over less than 2 cm length is safe and favours functional recovery. These repair and recent motion protocols lead to remarkably more reliable repairs, with over 80% good or excellent outcomes achieved rather consistently after Zone 2 repair along with infrequent need of tenolysis. Despite slight variations in repair methods, they all consider general principles and should be followed. Outcomes of Zone 2 repairs are not dissimilar to those in other zones with very low to zero incidence of rupture.

An Analysis of the Clinical Efficacy of Early Dynamic Orthosis after Finger Extensor Digitorum Rupture

OBJECTIVE

The main objective is to compare the clinical efficacy of the early use of dynamic orthosis in patients with a finger extensor digitorum rupture.

METHODS

A total of 50 patients with hand and foot trauma who received surgical treatment in our hospital from March 2017 to February 2021 were selected, and two patients were excluded from the study. The patients were randomly divided into two groups. The control group (group A) was treated with plaster fixation and routine rehabilitation, and the study group (group B) underwent dynamic low-temperature thermoplastic plate fixation and routine rehabilitation. Total active motion (TAM) and total passive motion (TPM) of the injured finger before treatment, one month after treatment, two months after treatment, and after corrective treatment were compared.

RESULTS

After treatment following a finger extensor digitorum rupture, the TAM and TPM of the injured fingers increased significantly in both groups. The TAM and TPM in group B were significantly better than those in group A after one and two months of treatment (P < 0.05). After two months of treatment, the rates of improvement in TAM and TPM in group B were significantly higher than those in group A.

CONCLUSION

The early use of dynamic orthosis can significantly improve the motor function and motion amplitude of the injured finger, increase the elasticity and extension of the finger extensor digitorum, and promote the recovery of muscle strength. It is an effective corrective method for tendon contracture after finger extensor digitorum rupture and has great value in clinical application.

Basic science approaches to common hand surgery problems

The field of hand surgery is constantly evolving to meet challenges of populations with increasing age and higher demands for active living. While our surgical care has improved over the last decades, it seems that future major improvement in outcomes of clinical treatment will come through advances in biologics and the translation of major discoveries in basic science. This article aims to provide an update on where basic science solutions may answer some of the most critical issues in hand surgery, with a focus on augmentation of tissue repair.

Important updates of finger fractures, entrapment neuropathies and wide-awake surgery of the upper extremity

Hand surgery is rapidly changing. The wide-awake approach, minimum dissection surgery and early protected movement have changed many things. This is an update of some of the important changes regarding early protected movement with K-wired finger fracture management, simplification of nerve decompression surgery, such as elbow median and ulnar nerve releases, and some new areas in performing surgery with wide-awake local anaesthesia without tourniquet.

The Impact of Dividing the Flexor Tendon Pulleys on Tendon Excursion and Work of Flexion in a Cadaveric Model

PURPOSE

The A2 and A4 pulleys of the flexor tendon system have traditionally been considered critical components of efficient digital flexion. This dogma has recently been challenged. Using fresh human cadaveric hands and a model to measure force and excursion, we sought to clarify the clinical importance of releasing different pulleys.

METHODS

Combinations of A1, A2, and A4 pulleys were released on the index, middle, ring, and little fingers of fresh, cadaveric hands. The excursion was measured as the distance the tendon was pulled by the motor to achieve palm touchdown. The force applied by the motor was constant (25 N); work was derived from the product of force and excursion (distance). The change in excursion and work needed to achieve palm touchdown before and after pulley release was measured. Excursion varies among digits and specimens at baseline; therefore, the percentage change from the intact state was used to compare groups. We compared A2 versus A1, A4 versus A1, A4 versus A2, A1 + A2 versus A2, and A1 + A4 versus A4.

RESULTS

Isolated A2 or A4 release had the greatest individual impact on the excursion (4.77% ± 1.52% and 3.88% ± 1.93%, respectively). When A1 was released with A2 (9.90% ± 2.52%), the additional impact on the excursion was significant; however, when A1 was released with A4 (2.63% ± 2.81%), the impact was marginal. No clinically or statistically significant change in the work of flexion was detected.

CONCLUSIONS

A1 release was clinically significant when added to A2 release but not when added to A4 release. Sacrifice of the A2 and A4 pulleys resulted in a statistically significant, but clinically negligible, difference in flexor tendon excursion. These data suggest that the A1 pulley should be preserved when other proximal pulley components are likely to be compromised. These data also add further support to the concept that the A2 pulley or the A4 pulley can be released as needed for optimal tenorrhaphy.

CLINICAL RELEVANCE

During flexor tendon repair, the length of contiguous pulley release may have more impact on final tendon excursion than which specific pulleys are released.

The impact of transverse components on 4-strand tendon repairs

We investigated the effects of the transverse components of a tendon core suture on tensile resistance and strength of 4-strand repairs. Forty-four pig flexor tendons were repaired with one of the following four methods: double Tsuge, U-shaped, 4-strand cross and 4-strand rectangular repairs. We recorded the number of the repaired tendons that formed a 2 mm gap between the tendon ends during cyclic loading for 20 cycles, stiffness of the tendon at the 1st and 20th cycle, gap distance at the repair site and ultimate strength of the repair at the 20th cycle. When transverse components were added to the core suture, a greater number of tendons formed a 2 mm gap during cyclic loading. The stiffness gradually decreased, and the repair site's gap distance after cyclic loading increased with the presence of transverse components of the sutures. We conclude that the core suture's transverse components negatively impact the tensile resistance of 4-strand tendon repairs.

Measurement of finger joint motion after flexor tendon repair: smartphone photography compared with traditional goniometry

The purpose of our study was to determine whether smartphone photography is as reliable and valid as clinical goniometry for measuring interphalangeal joint range of motion. We conducted a retrospective review of 37 fingers in 33 patients after flexor tendon repair. The measurements on photographs taken with a smartphone by a surgeon were compared with manual measurements with goniometry by the same surgeon. Pearson coefficients and interclass correlation coefficients were all above 0.85, and Bland-Altman analysis demonstrated that at least 35 of 37 measurements were within the 95% confidence interval in all variables. According to the Tang criteria, the total number of excellent and good results were equivalent according to both methods. There was high interobserver reliability between measurements by surgeons and a therapist. We conclude that if the pictures are properly taken, the measurement of the angles in the smartphone pictures are as reliable as measuring the angles with goniometry and that grading of the results according to the two methods gives identical results.

Up to five-week delay in primary repair of Zone 2 flexor tendon injuries: outcomes and complications

We report the outcomes of delayed primary repair of flexor tendons in Zone 2 in 31 fingers and thumb (28 patients) averaging 15 days (range 4-37) after injury in 2020. The delay was longer than usual due to the COVID-19 pandemic. The tendons were repaired with a 6-strand core suture (M-Tang method) or a double Tsuge suture and a peripheral suture. This was followed by an early, partial-range, active flexion exercise programme. Adhesions in four digits required tenolysis. These patients were not with longest delay. Outcomes of two improved after tenolysis. The other two patients declined further surgery. One finger flexor tendon ruptured in early active motion. This was re-repaired, and final outcome was good. Overall excellent and good results using the Tang criteria were in 27 out of 31 fingers and thumbs (87%). The time elapsed between the injury and surgery is not an important risk factor for a good outcome, rather it depends on proper surgical methods, the surgeon's experience and early mobilization, properly applied. Adhesions may occur, but they can be managed with tenolysis.Level of evidence: IV.

Early active mobilization after primary repair of the flexor pollicis longus tendon

BACKGROUND

There have been few studies regarding primary flexor tendon repair of the thumb following early active mobilization, whereas there have been multiple such studies of the finger. This study examined the outcomes of patients who underwent early active mobilization after primary repair of the flexor pollicis longus tendon.

METHODS

This study was a retrospective case series. Between 1993 and 2019, 17 thumbs of 17 consecutive patients with complete flexor pollicis longus tendon lacerations were treated using the Yoshizu #1 technique, followed by early active mobilization. The mean time between injury and primary flexor tendon repair was 2 days. Two thumbs had zone T1 injuries and 15 had zone T2 injuries. Mobilization of the thumb began on the first postoperative day with a combination of active extension and passive and active flexion. The mean follow-up period was 8 months. The percentage of total active motion of the thumb was regarded as the sum of the active motion of the two joints, divided by 140°. Functional outcomes were graded in accordance with the Strickland criteria.

RESULTS

Three repair ruptures occurred in thumbs treated by inexperienced surgeons. Excluding tendon ruptures, the mean percentage of total active motion of the thumb was 83%. The mean active flexion of the interphalangeal and metacarpophalangeal joints was 62° and 64°. The mean extension deficit was 8.8° at the interphalangeal joint and 7.5° at the metacarpophalangeal joint. According to Strickland's criteria, repairs to eight thumbs were ranked excellent, three were good, one was fair, and five were poor.

CONCLUSIONS

Our results are not inferior to the findings of previous reports regarding early postoperative mobilization after primary flexor pollicis longus tendon repair, in terms of the acquisition of active thumb motion. Poor outcomes result from repair rupture and increased extension deficits of the interphalangeal and metacarpophalangeal joints.

Management of spaghetti wrist under WALANT technique

This study aimed to evaluate the effectiveness of the WALANT technique in managing spaghetti wrist lacerations. Thirteen consecutive patients with spaghetti wrist laceration were operated on under WALANT technique and followed prospectively. All patients were operated on by the same hand surgeon in a university hospital setting. At the final follow-up, arterial patency, tendon repair, nerve regeneration, handgrip strength and overall patient satisfaction were assessed. All patients were male, with a mean age of 23.8 ± 7.7 years (range, 18-42). The mean waiting time from admission to operation was 33.6 ± 5.1 min (range, 26-42). The operation lasted a mean 119.6 ± 33.8 min (range, 75-185). Mean time from admission to discharge was 269.3 ± 35.0 min (range, 225-341). Mean VAS for intraoperative pain was 1.0 ± 0.9 points (range, 0-3). Patients were followed up for at least 6 months: mean 9.8 ± 1.6 months (range, 7-12). Ten of the 12 repaired arteries were patent and 2 were occluded at the final follow-up. Six of the 17 repaired nerves were evaluated as excellent, 9 as good and 2 as fair on 2-point discrimination test. Total active range of motion was perfect in 6 patients, good in 6, and fair in 1. Grip strength was averaged 86.8% (range, 76.9-93.5%) of the contralateral value. All patients were either very satisfied (n: 9) or satisfied (n: 4). The WALANT technique can be used for spaghetti wrist lacerations involving the tendons, arteries and nerves, with favorable outcome. Major arterial anastomosis can be performed without any surgical limitation.

Use of Thermoplastic Rings Following Venting of Flexor Tendon Pulleys: A Biomechanical Analysis

PURPOSE

Normal digital flexion relies on flexor tendon pulleys to convert linear muscular force to angular digital motion. However, there is a growing trend to vent them partially during flexor tendon repair. The objective of this study was to examine the effects of a thermoplastic ring, acting as an external pulley, on flexor tendon biomechanics and finger range of motion (ROM) after pulley venting.

METHODS

We tested 15 cadaveric digits using an in vitro active finger motion simulator. We measured loads induced by flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP) as well as joint ROM with sequential sectioning of the A2, A3, and A4 pulleys compared with an intact pulley condition. At each stage, external thermoplastic pulley rings were applied snugly over the proximal and middle phalanges to recreate A2 and A4 function, respectively.

RESULTS

After complete venting of the A2, A3, and A4 pulleys, proximal interphalangeal joint ROM significantly decreased by 13.4° ± 2.7° and distal interphalangeal joint ROM decreased by 15.8° ± 2.1°. Application of external rings over the proximal and middle phalanx resulted in a residual ROM decrease of 8.3° ± 1.9° at the proximal interphalangeal joint and 7.9° ± 2.1° at the distal interphalangeal joint, nearly restoring ROM. Similarly, complete pulley venting resulted in reduced FDS load by 37% and FDP load by 50% compared with intact pulleys. After application of external rings, loads were restored almost to normal, with a 9% reduction for FDS load and 9% reduction for FDP load compared with intact pulleys.

CONCLUSIONS

The application of thermoplastic rings acting as external pulleys is an effective, noninvasive, and reproducible approach to restore flexor tendon biomechanics and digit ROM after pulley venting.

CLINICAL RELEVANCE

Thermoplastic rings may be a useful therapeutic adjunct in restoring joint ROM and flexor tendon loads after surgical venting of the pulleys.

Sustained-Release Hydrogel-Based Rhynchophylline Delivery System Improved Injured Tendon Repair

During the injured flexor tendon healing process, tendon tissue is easy to form extremely dense adhesion with the surrounding tissue, which causes the serious influence of hand function recovery. Uncaria is widely used in clinic and its main composition, Rhynchophylline (Rhy), has been reported on its good therapeutic effect, which could effectively inhibit the intra-abdominal adhesion formation. However, the therapeutic effect of Rhy on tendon healing and adhesion formation is still unclear. Due to the short half-life of Rhy, hyaluronic acid (HA) sustained-release system for Rhy delivery was constructed and it could also avoid drug from the undesired loss during the transit. After Rhy delivery system was applied around the injured tendons, adhesion formation, gliding function and healing strength of tendons were evaluated. Our results showed that the gliding excursion and healing strength of repaired tendons were both significantly increased, as well as the adhesion was inhibited. From in vivo experiments, Rhy could be able to increase the expression of Col Ⅰ/Col Ⅲ and helped fibroblasts to ordered organization for tendon tissues. But for adhesion tissues, Rhy promoted the apoptosis and accelerated the degradation of extracellular matrix. In vitro study showed Rhy could help tenocytes stimulated with TGF-β1 to recover to normal cell functions involving cell proliferation and apoptosis level. Through high-throughput sequencing, we found that Rhy was involved in the regulation of Extracellular Matrix (ECM) signaling pathway. We draw a conclusion that Rhy enhanced the tendon healing and prevented adhesion formation through inhibiting the phosphorylation of Smad2. In a word, this sustained release system of Rhy may be a promising strategy for the treatment of injured tendons.

Getting Better Results in Flexor Tendon Surgery and Therapy

Recently, better outcomes have been reported when up-to-date developments in flexor tendon surgery and therapy were followed. Slightly tensioned multistrand repairs, judicious venting of pulleys, and early active motion are widely accepted principles. In addition to these principles, tailoring of the repair according to intraoperative active movement with wide awake local anesthesia no tourniquet (WALANT) surgical setting is recommended for better results. We aimed to describe our up-to-date approach to flexor tendon surgery and therapy with the help of visual communication tools of this age. The ideal primary repair of flexor tendons, the management of delayed presentation flexor tendon injuries, the key steps to achieve better results with flexor tendon therapy, and the tele-rehabilitation experience during COVID-19 pandemic will be highlighted. Zone 2 flexor tendon injuries are the most demanding part and will be focused on.

Wide awake surgery for flexor tendon primary repair: A literature review

Flexor tendon injuries are extremely challenging conditions to manage for hand surgeons. Over the last few years enormous progress has been made for the treatment of these lesions with new surgical approaches being performed. One of these is the wideawake local anesthesia no tourniquet (WALANT) technique, also known as Wide Awake Technique that allows tendon repair under local anesthesia, enabling the tendon to move actively during surgery. Dynamic movement of the tendon during surgery is crucial for the orthopedic surgeon in order to understand if the tendon has been correctly repaired before leaving the operatory table. An electronic literature research was carried out on Pubmed, Google Scholars and Cochrane Library using ((Flexor tendon injury) OR (flexor tendon) OR (injury muscle tendon) OR (flexor pollicis longus tendon) AND ((wide awake repair) OR (wide awake) OR (wide awake hand surgery))as search terms. Authors believe that WALANT is an enormous add-on in the management of patients with flexor tendon injuries mainly because it allows direct visualization of the repair during flexion and extension movement of the fingers and also because it avoids general anesthesia or brachial plexus being more cost effective. The aim of these review was therefore to sum up the evidences available so far on the wade awake technique as an emerging treatment for patients with flexor tendon injuries.

Tenolysis rate after zone 2 flexor tendon repairs

Objectives

This study aims to evaluate the tenolysis rates of zone 2 flexor digitorum profundus (FDP) with flexor digitorum superficialis (FDS) tendon repairs using four-strand technique and early passive motion exercises.

Patients and methods

In this retrospective study, we performed zone 2 flexor tendon repairs in 149 patients (117 males, 32 females, mean age 33.3±12.9 years; range, 13 to 72 years) (82 right and 67 left hands) between November 2014 and January 2019. A total of 194 FDP and FDS tendons were repaired primarily by using modified Kessler and Bunnell methods. Patients underwent pure passive motion protocols after surgery according to modified Duran’s protocol. No active flexion components were added until postoperative fourth week.

Results

Twenty-three out of 149 patients and 28 out of 194 fingers (14.43%) had tenolysis. There was no significant relationship between the number of operated fingers, gender, and tenolysis rate (p=0.836, p=0.584, respectively).

Conclusion

The repair of the FDP with FDS tendon increases the tenolysis rate in zone 2. The tenolysis rate does not change according to the number or distribution of injured fingers and gender of the patient.

Growth and Stem Cell Characteristics of Tendon-Derived Cells with Different Initial Seeding Densities: An In Vitro Study in Mouse Flexor Tendon Cells

Tendon stem/progenitor cells (TSPCs) are considered promising seed cells for tendon regeneration. Previous studies reported that a low seeding density favors TSPC growth, whereas a high seeding density favors tenocyte growth. We aimed to distinguish TSPCs from tenocytes by seeding tendon-derived cells at a density gradient. In this study, tendon-derived cells were isolated from flexor digitorum profundus tendons of mice and seeded at the initial densities of 50, 500, 5,000, and 50,000/cm². We found that distinct cell colonies were formed from cells with initial seeding densities of 50 and 500/cm², but colonies were not discernible for cells seeded at 5,000 and 50,000/cm². There was a positive correlation between cell proliferation rate and seeding density, but a negative correlation between cell senescence and seeding density. The cell proliferation rate decreased gradually during serial passages. All cells exhibited restricted differentiation potentials, and expressed stem cell markers and relatively high levels of tenogenic markers without notable differences among cells seeded at different densities. We concluded that a pure population of TSPCs could not be isolated from mouse digital flexor tendons through culturing cells at a density gradient. Cells seeded at low densities had very limited proliferative ability and did not show more prominent stem cell characteristics when compared with cells seeded at high densities.

[Postoperative treatment and rehabilitation following flexor tendon injuries]

BACKGROUND

The ideal surgical and postoperative treatment for flexor tendon injuries, especially in zone 2, is still subject to continuous modifications and professional discussions.

OBJECTIVE

Presentation of established rehabilitation concepts, specific problems and new treatment approaches with practical recommendations for application.

MATERIAL AND METHODS

Comparison of commonly used treatment concepts by assessing surgical flexor tendon repair, splint choice and clinical application in patients. Discussion of new surgical approaches and standards and their influence on postoperative therapy after flexor tendon injuries.

RESULTS

The Washington regimen has retained its status as the standard in the current follow-up treatment of flexor tendon injuries. New suture materials and techniques enable early active rehabilitation of sutured flexor tendons with good clinical results, such as increased range of motion for interphalangeal joint extension and improved distal interphalangeal joint flexion with overall acceptable frequencies of suture rupture.

CONCLUSION

A stable tendon repair with smooth gliding is the foundation for treatment after flexor tendon injuries. After intraoperative active digital extension-flexion testing of the sutured tendon an early active rehabilitation approach should follow. New splint designs in combination with primary stable tendon suture techniques have the potential to improve the postoperative outcome, presupposing a reliable cooperation of the patient.