Tendon healing, edema, and resistance to flexor tendon gliding: clinical implications

Early active movement with relative motion flexion splint for the management of zone 1-2 flexor tendon repairs: Case series

BACKGROUND

There is limited literature evidence on the use of relative motion flexion splint after flexor tendon repairs.

OBJECTIVES

We aimed to report the clinical use of early active movement with a relative motion flexion splint and to determine the outcomes of a consecutive series in patients with zone 1-2 flexor tendon repair.

METHODS

We included 14 patients with one-stage flexor tendon repair. An active rehabilitation program was initiated in the first week with a static dorsal block splint, which was removed in the third week, and patients started to use the relative motion flexion splint. Total active motion (TAM) of the injured finger at 8, 12, and 16 weeks after surgery was assessed as described by Strickland and Glogovac.

RESULTS

The mean TAM of the injured fingers was as follows: 102.5 ± 41.49° (25°-180°) at week 8; 123.42 ± 40.94° (45°-190°) at week 12; and 148 ± 38.18° (90°- 200°) at week 16. Final TAM grades of the patients at week 16 were as follows: excellent (six patients); good (five patients); and fair (three patients). There were no tendon ruptures and secondary surgeries.

CONCLUSION

Early active movement and the use of relative motion flexion splint seem to be promising strategies for flexor tendon zone 1-2 repair management.

Does distal interphalangeal joint arthrodesis affect proximal interphalangeal joint arthroplasty outcomes in the same finger?

The purpose of this study was to analyse the 1-year outcomes after combining a surface replacing proximal interphalangeal joint arthroplasty and a distal interphalangeal screw arthrodesis and to compare the combined surgery with proximal interphalangeal joint arthroplasty alone. To obtain two groups with similar baseline data from our prospective registry, propensity score matching was used to match 23 fingers with the combined operations with 115 fingers with proximal interphalangeal joint arthroplasty alone. One year after surgery, the mean ranges of motion were 60° (95% CI: 53° to 67°) in the combined group and 63° (95% CI: 60° to 66°) in the control group and did not differ significantly. Grip strength, the brief Michigan Hand Questionnaire and pain also did not differ between the groups 1 year after surgery. All the proximal interphalangeal implants in patients treated with a distal interphalangeal screw arthrodesis remained in situ. Combining proximal interphalangeal joint arthroplasty with distal interphalangeal arthrodesis leads to 1-year outcomes that are similar to those achieved by proximal interphalangeal joint replacement alone.Level of evidence: III.

Flexor Tendon Repair: Avoidance and Management of Complications

The proper technique for flexor tendon repair has been well established through numerous bench science and clinical studies. However, less is known about strategies to avoid and manage postoperative complications. This article discusses the common complications after flexor tendon repair, such as repair site rupture and adhesion formation. This article also addresses strategies to prevent and manage these complications. The foundation for preventing many of these complications is ensuring a strong repair without gapping at time zero, which will enable the accrual of tensile strength through early initiation of motion.

Surgical Considerations for Flexor Tendon Repair: Timing and Choice of Repair Technique and Rehabilitation

Flexor tendon injuries are common and occur mostly due to penetrating trauma. Surgical repair is required for complete tendon lacerations, and many techniques exist. This article reviews the principles of tendon structure, function, healing, and anatomy. Repair techniques are discussed in detail for each flexor tendon zone. Postoperative rehabilitation greatly influences outcomes, and several protocols are described.

Direct Repair of Flexor Tendons Close to Bony Insertion and Ruptured Collateral Ligaments

Lacerated flexor tendons close to bony junction are commonly repaired using a pullout suture. However, these injuries very close to the tendon-bone junction can be repaired with robust direct suture repair of the proximal tendon stump with the short residual tendon stump and any local tissues such as periosteum and joint volar plate. Subacute or chronic traumatic rupture at the midpart of the collateral ligaments can also be repaired by "refreshing" the divided ligament ends and repairing the ligament stumps to local tissues with multiple sutures often combined with tightening the elongated joint capsule.

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.

An In Vivo Comparison: Novel Mesh Suture Versus Traditional Suture-Based Repair in a Rabbit Tendon Model

Purpose

Despite advancements in surgical techniques, suture pull-though and rupture continue to limit the early range of motion and functional rehabilitation after flexor tendon repairs. The aim of this study was to evaluate a suturable mesh compared with a commonly used braided suture in an in vivo rabbit intrasynovial tendon model.

Methods

Twenty-four New Zealand female rabbits (3-4 kg) were injected with 2 units/kg botulinum toxin evenly distributed into 4 sites in the left calf. After 1 week, the animals underwent surgical tenotomy of the flexor digitorum tendon and were randomized to repair with either 2-0 Duramesh suturable mesh or to 2-0 Fiberwire using a 2-strand modified Kessler and 6-0 polypropylene running epitendinous suture. Rabbits were killed at 2, 4, and 9 weeks after surgery.

Results

Grouping across time points, 58.3% (7 of 12) of Duramesh repairs were found to be intact for the explant compared with 16.7% (2 of 12) of Fiberwire repairs (P = .09). At 2 weeks, the mean Duramesh repairs were significantly stronger than the Fiberwire repairs with a mean failure load of 50.7 ± 12.7 N compared to 14.8 ± 18.3 N (P = .02). The load supported by the Duramesh repairs at 2 weeks (mean 50.7 ± 12.7 N) was similar to the load supported by both Fiberwire (52.2 ± 13.6 N) and Duramesh (57.6 ± 22.3 N) at 4 weeks. The strength of repair between Fiberwire and Duramesh at 4 weeks and 9 weeks was not significantly different.

Conclusions

The 2-strand tendon repair with suturable mesh achieved significantly greater strength at 2 weeks than the conventional suture material. Future studies should evaluate the strength of repair prior to 2 weeks to determine the strength curve for this novel suture material.

Clinical Relevance

This study evaluates the utility of a novel suturable mesh for flexor tendon repair in an in vivo rabbit model compared with conventional suture material.

Tensile load on the flexor digitorum profundus tendon during palmar and lateral blocking exercises: Influence on blocking force and distal interphalangeal joint flexion angle

STUDY DESIGN

This is a basic science research.

INTRODUCTION

Isolating excursion of the flexor digitorum profundus (FDP) in zones I and II is common practice in the current management after flexor tendon repair. During this procedure, the proximal interphalangeal joint is sometimes fully extended with unmeasured external forces at the middle phalanx when the distal interphalangeal joint is actively flexed.

PURPOSE OF THE STUDY

The purpose of the study was to investigate the incremental effect of external force with palmar blocking versus lateral blocking and increased angles of flexion on internal tendon forces at the repair site for a safer application of force by the treating therapist.

METHODS

Eight human cadaveric fingers were studied. To simulate palmar or lateral finger blocking, a compression force of blocking was applied from 5N (510 grams) to 25N (2,550 grams) on the skin surface of the palmar or the lateral aspect of each of these middle phalanges in 5N increments. The tensile load on the FDP tendon during distal interphalangeal joint flexion from 0° to 60° was measured in 10° increments.

RESULTS

During palmar blocking, the tensile load was significantly increased with increases in palmar blocking force. However, no significant increase in the tensile load on the FDP tendon was observed at any lateral blocking.

DISCUSSION

Lateral blocking exercise can be performed with less tensile force on the FDP tendon when performing blocking exercise after flexor tendon injury repair.

CONCLUSIONS

This study supports the concept that lateral blocking with incremental joint angles allows a safer application of force for the healing tendon.

Improving flexor tendon gliding by using the combination of carboxymethylcellulose‑polyethylene oxide on murine model

The current approach to flexor tendon injuries is complex and is no longer limited to suturing techniques. Strategies for improving hand function currently include rehabilitation protocols, appropriate suturing materials and techniques, changing the gliding surface by using lubricants and providing growth factors. One product, originally used in spinal surgery, has been shown to be effective in preventing postoperative adhesions. It is a combination of carboxymethylcellulose and polyethylene oxide-Dynavisc^® (FzioMed, Inc.). The aim of the present study was to test the effect of Dynavisc^® on acute injuries of the intrasynovial flexor tendons in the prevention of postoperative adhesions and the improvement of functional results. The study was performed on 20 Wistar rats distributed in two groups. The control group, represented by 10 rats, in which after the reconstruction of the flexor tendon, the peritendinous area was injected with saline solution and the study group, in which the peritendinous area was injected with a single administration of the lubricating gel, Dynavisc^® (carboxymethylcellulose and polyethylene oxide). At 4 and 12 weeks, the rats were sacrificed and tissue biopsy consisted of tendon fragments and adjacent tissue. The evaluation of the results was performed by measuring the adhesion score and observing histological parameters. The presence of important adhesions was found in the control group compared with the group treated with Dynavisc^®, where a supple and smooth tendon, with significantly fewer adhesions were found. The differences between the two groups were significant, thus indicating the efficiency of the lubricant in preventing adhesions. This study supported the important role of Dynavisc^® in the regeneration of the tendon and the peritendinous structures, by limiting aberrant fibrous proliferation in the regeneration process and helping to build a peritendinous space.

Phalangeal and Metacarpal Fractures of the Hand: Preventing Stiffness

Fractures of the phalangeal or metacarpal bones of the hand are common. Many of these fractures are treated without surgery. However, both conservative and operative management of fractures of the hand can result in stiffness. Stiffness is the most common complication in the management of hand fractures. The key to preventing stiffness is early range of motion exercises. This article challenges many of the current treatment regimens offered to patients with the so-called unstable fractures. The evaluation of the patients' function is the primary factor that should determine the course of conservation versus operative management. X-rays do not demonstrate function and therefore act as an adjunct only to the care of the patient. The goal of treating hand fractures is to restore function. Early motion may not only improve healing but may also hasten the return to normal hand function. The tenets of how to prevent stiffness are described in this review.

Rehabilitation after flexor tendon repair and others: a safe and efficient protocol

In this review I detail the protocol that I use after flexor tendon repair and outline my experience regarding how its framework might be used for other disorders. The early passive-active flexion protocol has a sufficient number of cycles of active flexion in each exercise session, which is at least 40, and ideally 60 to 80. The frequency of exercise sessions may range from 4 to 6 a day, distributed in the morning, afternoon and evening. Increasing the number of daily sessions without a sufficient number of runs in each session is ineffective. In the first 2-3 weeks after surgery, active digital flexion should go through only a partial range. In weeks 4-6, the patient gradually moves through the full range. With modifications, I suggest generalization of the partial-range finger motion to therapy after treating other hand injuries. I consider partial-range active flexion a generalizable working principle for different hand disorders.

Biomechanical comparison of tenorrhaphy constructs for tendon reconstructions and transfers

With tendon transfers or reconstructions, the tenorrhaphy must be strong enough to withstand early mobilization in the immediate postoperative period to decrease adhesion formation and optimize functional outcomes. The purpose of this study was to compare the strength, bulk, and gliding resistance of four common tendon-to-tendon attachment constructs. A biomechanical study was performed utilizing 80 cadaveric tendons to compare four common tendon tenorrhaphy constructs: the end-weave (EW); Pulvertaft (PT); single-pass, side-to-side (SP-STS); and simple, side-to-side (STS) attachments. The primary outcome measures investigated included tenorrhaphy morphology, gliding resistance, tensile strength, and deformation at failure of the different constructs. A total of 40 tendon pairs, 10 per repair group, were constructed, biomechanically evaluated, and outcomes were compared. There were no significant differences in the cross-sectional area of the native tendon (p = 0.334) or repair site (p = 0.564) and no difference in the added bulk of the repair (p = 0.663) between the repair groups. Gliding resistance was not significantly different between the repair groups (p = 0.110). The SP-STS repair was significantly stronger (p < 0.001), stiffer (p < 0.001), and exhibited less displacement at peak load (p = 0.004), and greater force generation at 1 cm of displacement (p = 0.002) compared to the other constructs. The SP-STS is significantly stronger, without a significant difference in bulk and gliding resistance compared to the PT, EW, STS repairs. SP-STS can be utilized in tendon transfers and reconstructions to safely permit early active mobilization.

Mechanisms of reducing joint stiffness by blocking collagen fibrillogenesis in a rabbit model of posttraumatic arthrofibrosis

Posttraumatic fibrotic scarring is a significant medical problem that alters the proper functioning of injured tissues. Current methods to reduce posttraumatic fibrosis rely on anti-inflammatory and anti-proliferative agents with broad intracellular targets. As a result, their use is not fully effective and may cause unwanted side effects. Our group previously demonstrated that extracellular collagen fibrillogenesis is a valid and specific target to reduce collagen-rich scar buildup. Our previous studies showed that a rationally designed antibody that binds the C-terminal telopeptide of the α2(I) chain involved in the aggregation of collagen molecules limits fibril assembly in vitro and reduces scar formation in vivo. Here, we have utilized a clinically relevant arthrofibrosis model to study the broad mechanisms of the anti-scarring activity of this antibody. Moreover, we analyzed the effects of targeting collagen fibril formation on the quality of healed joint tissues, including the posterior capsule, patellar tendon, and subchondral bone. Our results show that blocking collagen fibrillogenesis not only reduces collagen content in the scar, but also accelerates the remodeling of healing tissues and changes the collagen fibrils’ cross-linking. In total, this study demonstrated that targeting collagen fibrillogenesis to limit arthrofibrosis affects neither the quality of healing of the joint tissues nor disturbs vital tissues and organs.

Evaluation of Hand Tendon Elastic Properties During Rehabilitation Through High-Frequency Ultrasound Shear Elastography

Tendon injuries lead to tendon stiffness, which impairs skeletal muscle movement. Most studies have focused on patellar or Achilles tendons by using ultrasound elastography. Only a few studies have measured the stiffness of hand tendons because their thickness is only 1-2 mm, rendering clinical ultrasound elastography unsuitable for mapping hand tendon stiffness. In this study, a high-frequency ultrasound shear elastography (HFUSE) system was proposed to map the shear wave velocity (SWV) of hand flexor tendons. A handheld vibration system that was coaxially mounted with an external vibrator on a high-frequency ultrasound (HFUS) array transducer allowed the operators to scan hand tendons freely. To quantify the performance of HFUSE, six parameters were comprehensively measured from homogeneous, two-sided, and three-sided gelatin phantom experiments: bias, precision, lateral resolution, contrast, contrast-to-noise ratio (CNR), and accuracy. HFUSE demonstrated an excellent resolution of [Formula: see text] to distinguish the local stiffness of thin phantom (thickness: 1.2 mm) without compromising bias, precision, contrast, CNR, and accuracy, which has been noted with previous systems. Human experiments involved four patients with hand tendon injuries who underwent ≥2 months of rehabilitation. Using HFUSE, two-dimensional SWV images of flexor tendons could be clearly mapped for healthy and injured tendons, respectively. The findings demonstrate that HFUSE can be a promising tool for evaluating the elastic properties of the injured hand tendon after surgery and during rehabilitation and thus help monitor progress.

Flexor tendon injuries: Repair & Rehabilitation

Flexor tendon injuries are common and occur mostly by penetrating trauma. Suspected flexor tendon injuries require a thorough clinical assessment and often are not isolated injuries. A detailed understanding of flexor tendon anatomy and spatial relationships is essential, especially when repairing multi-tendon injuries. Principles of flexor tendon repair include a strong suture construct, minimising gap formation between tendon ends, preserving tendon blood supply and providing a smooth repair interface. Moreover, adequate exposure of the zone of injury using full-thickness skin flaps and preservation of neurovascular and pulley structures is essential. In this article an overview of contemporary management strategies is presented. Today's hand surgeons and therapists can choose from a variety of treatment options when managing these important and potentially life-changing injuries.

Rehabilitation following surgery for flexor tendon injuries of the hand

BACKGROUND

Various rehabilitation treatments may be offered following surgery for flexor tendon injuries of the hand. Rehabilitation often includes a combination of an exercise regimen and an orthosis, plus other rehabilitation treatments, usually delivered together. The effectiveness of these interventions remains unclear.

OBJECTIVES

To assess the effects (benefits and harms) of different rehabilitation interventions after surgery for flexor tendon injuries of the hand.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials, the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register, MEDLINE, Embase, two additional databases and two international trials registries, unrestricted by language. The last date of searches was 11 August 2020. We checked the reference lists of included studies and relevant systematic reviews.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs that compared any postoperative rehabilitation intervention with no intervention, control, placebo, or another postoperative rehabilitation intervention in individuals who have had surgery for flexor tendon injuries of the hand. Trials comparing different mobilisation regimens either with another mobilisation regimen or with a control were the main comparisons of interest. Our main outcomes of interest were patient-reported function, active range of motion of the fingers, and number of participants experiencing an adverse event.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, extracted data, assessed risk of bias and assessed the quality of the body of evidence for primary outcomes using the GRADE approach, according to standard Cochrane methodology.

MAIN RESULTS

We included 16 RCTs and one quasi-RCT, with a total of 1108 participants, mainly adults. Overall, the participants were aged between 7 and 72 years, and 74% were male. Studies mainly focused on flexor tendon injuries in zone II. The 17 studies were heterogeneous with respect to the types of rehabilitation treatments provided, intensity, duration of treatment and the treatment setting. Each trial tested one of 14 comparisons, eight of which were of different exercise regimens. The other trials examined the timing of return to unrestricted functional activities after surgery (one study); the use of external devices applied to the participant to facilitate mobilisation, such as an exoskeleton (one study) or continuous passive motion device (one study); modalities such as laser therapy (two studies) or ultrasound therapy (one study); and a motor imagery treatment (one study). No trials tested different types of orthoses; different orthosis wearing regimens, including duration; different timings for commencing mobilisation; different types of scar management; or different timings for commencing strengthening. Trials were generally at high risk of bias for one or more domains, including lack of blinding, incomplete outcome data and selective outcome reporting. Data pooling was limited to tendon rupture data in a three trial comparison. We rated the evidence available for all reported outcomes of all comparisons as very low-certainty evidence, which means that we have very little confidence in the estimates of effect. We present the findings from three exercise regimen comparisons, as these are commonly used in clinical current practice. Early active flexion plus controlled passive exercise regimen versus early controlled passive exercise regimen (modified Kleinert protocol) was compared in one trial of 53 participants with mainly zone II flexor tendon repairs. There is very low-certainty evidence of no clinically important difference between the two groups in patient-rated function or active finger range of motion at 6 or 12 months follow-up. There is very low-certainty evidence of little between-group difference in adverse events: there were 15 overall. All three tendon ruptures underwent secondary surgery. An active exercise regimen versus an immobilisation regimen for three weeks was compared in one trial reporting data for 84 participants with zone II flexor tendon repairs. The trial did not report on self-rated function, on range of movement during three to six months or numbers of participants experiencing adverse events. The very low-certainty evidence for poor (under one-quarter that of normal) range of finger movement at one to three years follow-up means we are uncertain of the finding of zero cases in the active group versus seven cases in the immobilisation regimen. The same uncertainty applies to the finding of little difference between the two groups in adverse events (5 tendon ruptures in the active group versus 10 probable scar adhesion in the immobilisation group) indicated for surgery. Place and hold exercise regimen performed within an orthosis versus a controlled passive regimen using rubber band traction was compared in three heterogeneous trials, which reported data for a maximum of 194 participants, with mainly zone II flexor tendon repairs. The trials did not report on range of movement during three to six months, or numbers of participants experiencing adverse events. There was very low-certainty evidence of no difference in self-rated function using the Disability of the Arm, Shoulder and Hand (DASH) functional assessment between the two groups at six months (one trial) or at 12 months (one trial). There is very low-certainty evidence from one trial of greater active finger range of motion at 12 months after place and hold. Secondary surgery data were not available; however, all seven recorded tendon ruptures would have required surgery. All the evidence for the other five exercise comparisons as well as those of the other six comparisons made by the included studies was incomplete and, where available, of very low-certainty.

AUTHORS' CONCLUSIONS

There is a lack of evidence from RCTs on most of the rehabilitation interventions used following surgery for flexor tendon injuries of the hand. The limited and very low-certainty evidence for all 14 comparisons examined in the 17 included studies means that we have very little confidence in the estimates of effect for all outcomes for which data were available for these comparisons. The dearth of evidence identified in this review points to the urgent need for sufficiently powered RCTs that examine key questions relating to the rehabilitation of these injuries. A consensus approach identifying these and establishing minimum study conduct and reporting criteria will be valuable. Our suggestions for future research are detailed in the review.

Electrospun Water-Borne Polyurethane Nanofibrous Membrane as a Barrier for Preventing Postoperative Peritendinous Adhesion

Peritendinous adhesion is a major complication after tendon injury and the subsequent repairs or reconstructions. The degree of adhesion can be reduced by the interposition of a membranous barrier between the traumatized tendon and the surrounding tissue. In the present study, electrospun water-borne polyurethane (WPU) nanofibrous membranes (NFMs) were created for use after the reparation or reconstruction of tendons to reduce adhesion. In the electrospinning process, water was employed as the solvent for WPU, and this solvent was ecofriendly and nontoxic. The nanofibrous architecture and pore size of the WPU NFMs were analyzed. Their microporosity (0.78⁻1.05 µm) blocked the penetration of fibroblasts, which could result in adhesion and scarring around the tendon during healing. The release of WPU mimicked the lubrication effect of the synovial fluid produced by the synovium around the tendon. In vitro cell studies revealed that the WPU NFMs effectively reduced the number of fibroblasts that became attached and that there was no significant cytotoxicity. In vivo studies with the rabbit flexor tendon repair model revealed that WPU NFMs reduced the degree of peritendinous adhesion, as determined using a gross examination; a histological cross section evaluation; and measurements of the range of motion of interphalangeal joints (97.1 ± 14.7 and 79.0 ± 12.4 degrees in proximal and distal interphalangeal joints respectively), of the length of tendon excursion (11.6 ± 1.9 cm), and of the biomechanical properties.

Biomechanical Properties of a Novel Mesh Suture in a Cadaveric Flexor Tendon Repair Model

PURPOSE

Conventional suture repairs, when stressed, fail by suture rupture, knot slippage, or suture pull-through, when the suture cuts through the intervening tissue. The purpose of this study was to compare the biomechanical properties of flexor tendon repairs using a novel mesh suture with traditional suture repairs.

METHODS

Sixty human cadaveric flexor digitorum profundus tendons were harvested and assigned to 1 of 3 suture repair groups: 3-0 and 4-0 braided poly-blend suture or 1-mm diameter mesh suture. All tendons were repaired using a 4-strand core cruciate suture configuration. Each tendon repair underwent linear loading or cyclic loading until failure. Outcome measures included yield strength, ultimate strength, the number of cycles and load required to achieve 1-mm and 2-mm gap formation, and failure.

RESULTS

Mesh suture repairs had significantly higher yield and ultimate force values when compared with 3-0 and 4-0 braided poly-blend suture repairs under linear testing. The average force required to produce repair gaps was significantly higher in mesh suture repairs than in conventional suture. Mesh suture repairs endured a significantly greater number of cycles and force applied before failure compared with both 3-0 and 4-0 conventional suture.

CONCLUSIONS

This ex vivo biomechanical study of flexor tendon repairs using a novel mesh suture reveals significant increases in average yield strength, ultimate strength, and average force required for gap formation and repair failure with mesh suture repairs compared with conventional sutures.

CLINICAL RELEVANCE

Mesh suture-based flexor tendon repairs could lead to improved healing at earlier time points. The findings could allow for earlier mobilization, decreased adhesion formation, and lower rupture rates after flexor tendon repairs.

New Developments Are Improving Flexor Tendon Repair

New developments in primary tendon repair in recent decades include stronger core tendon repair techniques, judicious and adequate venting of critical pulleys, followed by a combination of passive and active digital flexion and extension. During repair, core sutures over the tendon should have sufficient suture purchase (no shorter than 0.7 to 1 cm) in each tendon end and must be sufficiently tensioned to resist loosening and gap formation between tendon ends. Slight or even modest bulkiness in the tendon substance at the repair site is not harmful, although marked bulkiness should always be avoided. To expose the tendon ends and reduce restriction to tendon gliding, the longest annular pulley in the fingers (i.e., the A2 pulley) can be vented partially with an incision over its distal or proximal sheath no longer than 1.5 to 2 cm; the annular pulley over the middle phalanx (i.e., the A4 pulley) can be vented entirely. Surgeons have not observed adverse effects on hand function after judicious and limited venting. The digital extension-flexion test to check the quality of the repair during surgery has become increasingly routine. A wide-awake surgical setting allows patient to actively move the digits. After surgery, surgeons and therapists protect patients with a short splint and flexible wrist positioning, and are now moving toward out-of-splint freer early active motion. Improved outcomes have been reported over the past decade with minimal or no rupture during postoperative active motion, along with lower rates of tenolysis.

Therapy Concepts for the Proximal Interphalangeal Joint

The principles of hand therapy for proximal interphalangeal joint disorders include protecting injured structures, minimizing patient discomfort, and optimizing patient recovery. Comprehension of hand anatomy, the nature of the injury being treated, and the phases of healing are critical when designing a safe and effective hand therapy program. Hand therapists use a combination of orthoses, guided exercises, and modalities to improve edema, sensitivity, range of motion, and function.

The effect of adding active flexion to modified Kleinert regime on outcomes for zone 1 to 3 flexor tendon repairs. A prospective randomized trial

In a prospective randomized study, we studied whether adding active flexion to a modified Kleinert regime changed outcomes of flexor tendon repairs in zone 1, 2 and 3 in 73 fingers (53 patients). Evaluation included active range of finger motion, grip and pinch strengths. Twelve months after surgery, the increase in range of active finger motion after adding active flexion was insignificant compared with that with the modified Kleinert regime. According to the Strickland criteria, 20 out of 29 fingers had excellent or good recovery after adding active flexion, as did 28 out of 34 fingers with the modified Kleinert regime; we could not detect significant improvement of the good and excellent rate. At 6 months, the pinch strength was significantly higher with the addition of active flexion. We failed to find that adding active finger flexion to the modified Kleinert regime improves the overall long-term results of repairs in zone 1 to 3, though recovery appeared faster, and the good and excellent recovery of zone 2 repairs was 17% greater with the active flexion protocol.

LEVEL OF EVIDENCE

I.

The Effects of Autologous Platelet-Rich Fibrin on Flexor Tendon Healing in a Rabbit Model

PURPOSE

Platelet-rich plasma containing large amounts of growth factors is purported to increase repaired flexor tendon strength. However, the use of bovine thrombin has the risk of antibody formation. We evaluated the effects of the newer generation autologous platelet-rich fibrin (PRF) on flexor tendon healing.

METHODS

We performed surgical repair of 32 flexor tendons from the index and ring digits of the hind paws of 8 New Zealand white rabbits. In the PRF group, the PRF membrane was either wrapped around or interposed between the repair sites. At 3 weeks after surgery, the tested tendons were subjected to range of motion analysis, cross-sectional area measurement, biomechanics testing, and histological analysis.

RESULTS

The results showed no significant increase in range of motion in the PRF group compared with the control group, but there was a significant increase in cross-sectional area of the tendons in the PRF group. The biomechanical testing suggested that the control had a higher load to failure and stress to failure but similar stiffness and modulus to the PRF group.

CONCLUSIONS

The PRF did not have a major influence on cellular organization. It also had an undesirable effect on the biomechanical properties of repaired flexor tendons.

CLINICAL RELEVANCE

The findings of this study suggest PRF may, in certain situations, hinder rather than enhance, the healing for repaired flexor tendons.

Robust thumb flexor tendon repairs with a six-strand M-Tang method, pulley venting, and early active motion

We present the outcomes of flexor pollicis longus tendon repairs in 34 thumbs using a six-strand M-Tang repair with venting of one or two pulleys according to site of tendon laceration. The A2 pulley was vented in all three thumbs with zone 1 injury. In 31 thumbs with zone 2 injuries, the oblique pulley was vented partially or entirely. Twenty-two thumbs had both the A1 and oblique pulleys vented. Six to 46 months post-surgery, 14 thumbs with zone 2 injuries were rated excellent, 13 good, three fair and one failure according to Tang criteria. No tendon ruptures or bowstringing occurred. Fourteen of 34 thumbs had deficits in interphalangeal joint extension averaging 13°. We conclude that venting of one or two pulleys may ensure recovery of thumb function without risking tendon bowstringing and that early active thumb motion is safe with a robust tendon repair.

LEVEL OF EVIDENCE

IV.

Outcomes of the six-strand M-Tang repair for zone 2 primary flexor tendon repair in 54 fingers

We repaired complete divisions of flexor tendons in zone 2 in 54 fingers using a six-strand core M-Tang repair method. Partial active digital motion started with early passive digital motion carried out first in the first 3-4 weeks after surgery and full range of active motion in later weeks. The patients were followed for 4-27 months. According to Strickland criteria or Tang criteria, 24 (83%) had excellent or good, four fair and one poor results in 28 fingers with follow-up of more than one year. In the other 25 fingers which were followed for less than 12 months, 19 (76%) had excellent and good, four fair and two poor results. There were no repair ruptures. We analysed outcomes against ages, gender, pulley integrity, accompanied injuries and follow-up times. The patients younger than 37 years old, male patients and with their A2 pulley(s) vented there were significantly better outcomes. The patients with longer than one year follow-up had significantly smaller extension deficits than those with less than one year follow-up.

LEVEL OF EVIDENCE

IV.

Early commencement of physical therapy in the acute phase following elective lower limb arthroplasty produces favorable outcomes: a systematic review and meta-analysis examining allied health service models

BACKGROUND

Temporal and dose-response relationships between allied health (AH) and recovery in the acute phase following lower limb (LL) arthroplasty are unclear. This systematic review investigates whether early commencement, additional therapy and/or weekend AH affects length of stay (LOS) and patient outcomes in the acute phase following LL arthroplasty.

METHODS

Electronic databases were searched in February 2015. Studies were included if they evaluated any of the following aspects of AH for adults following LL arthroplasty in the acute phase: Early compared to later therapy commencement; Additional therapy; or a 6- or 7-day service compared to a lesser service.

RESULTS

Twenty-four studies met the inclusion criteria, of which 19 investigated effects of physical therapy (PT) alone. Earlier PT reduced LOS (WMD = -1.23 days; 95% CI, -2.16 to -0.30) and resulted in higher probability of discharge directly home (relative risk = 1.45; 95% CI, 1.26-1.67). Addition of weekend PT reduced LOS (WMD = -1.04 days; 95% CI, -1.66 to -0.41) and improved function (SMD = 0.37; 95% CI, 0.02-0.73). Increasing PT from once to twice daily did not affect LOS (WMD = -0.35 days; 95% CI, -0.96-0.26) or function (SMD = 0.31; 95% CI, -0.06-0.71).

DISCUSSION

Early PT commencement and a weekend service may produce favorable outcomes following LL arthroplasty when baseline LOS is 4 days or more. Redistributing PT resources to commence as early as day of surgery regardless of weekday may accelerate postoperative recovery. Current, high quality research is needed to confirm these findings.

A knotless bidirectional-barbed tendon repair is inferior to conventional 4-strand repairs in cyclic loading

We divided 21 flexor digitorum profundus tendons in the index, middle and ring fingers in seven cadaver hands into three groups. The tendons were cut in zone 2 and repaired using a 4-strand cruciate core suture repair with one of the following three materials in each group: (1) a knotless repair with a 2-0 bidirectional-barbed suture, which has similar tensile strength as a 4-0 non-barbed suture used in the other two groups; (2) a knotted locking repair with a non-barbed 4-0 conventional suture; and (3) a non-locking repair with a non-barbed 4-0 knotless suture. The repaired fingers were cyclically loaded through a simulated active range of motion to a 5 N load. We monitored and recorded the gap sizes at regular intervals during the test. The 2-0 bidirectional-barbed suture group and non-barbed suture groups developed gaps of 2.2 mm after 10 cycles and 2.4 mm after 20 cycles, respectively. Over 1000 cycles, the mean gaps were 3.2 mm in the 4-0 conventional suture group and 9.1 mm in the 2-0 bidirectional-barbed group. The tendons in the 2-0 bidirectional-barbed group gapped earlier, with statistically significant differences compared with those in the locking repair with a non-barbed 4-0 knotless suture group. The repair strength of the barbed suture technique was inferior to the cruciate repairs using a conventional 4-0 non-barbed suture tested in this cyclic-loading model.

LEVEL OF EVIDENCE

Level V.

Clinical results of releasing the entire A2 pulley after flexor tendon repair in zone 2C

We report the results of complete release of the entire A2 pulley after zone 2C flexor tendon repair followed by early postoperative active mobilization in seven fingers and their comparisons with 33 fingers with partial A2 pulley release. In seven fingers, release of the entire A2 pulley was necessary to allow free gliding of the repairs in five fingers and complete release of both the A2 and C1 pulleys was necessary in two. No bowstringing was clinically evident in any finger. Two fingers required tenolysis. Using Tang's criteria, the function of two digits was ranked as excellent, four good and one fair; there was no failure. The functional return in these seven fingers was similar with that in 33 fingers with partial A2 pulley release; in these patients only one finger required tenolysis. Our results support the suggestion that release of the entire A2 pulley together with the adjacent C1 pulley does not clinically affect finger motion or cause tendon bowstringing, provided that the other pulleys are left intact.

LEVEL OF EVIDENCE

IV.

Rabbit Achilles tendon full transection model - wound healing, adhesion formation and biomechanics at 3, 6 and 12 weeks post-surgery

After tendon rupture repair, two main problems may occur: re-rupture and adhesion formation. Suitable non-murine animal models are needed to study the healing tendon in terms of biomechanical properties and extent of adhesion formation. In this study 24 New Zealand White rabbits received a full transection of the Achilles tendon 2 cm above the calcaneus, sutured with a 4-strand Becker suture. Post-surgical analysis was performed at 3, 6 and 12 weeks. In the 6-week group, animals received a cast either in a 180 deg stretched position during 6 weeks (adhesion provoking immobilization), or were re-casted with a 150 deg position after 3 weeks (adhesion inhibiting immobilization), while in the other groups (3 and 12 weeks) a 180 deg position cast was applied for 3 weeks. Adhesion extent was analyzed by histology and ultrasound. Histopathological scoring was performed according to a method by Stoll et al. (2011), and the main biomechanical properties were assessed. Histopathological scores increased as a function of time, but did not reach values of healthy tendons after 12 weeks (only around 15 out of 20 points). Adhesion provoking immobilization led to an adhesion extent of 82.7±9.7%, while adhesion inhibiting immobilization led to 31.9±9.8% after 6 weeks. Biomechanical properties increased over time, however, they did not reach full strength nor elastic modulus at 12 weeks post-operation. Furthermore, the rabbit Achilles tendon model can be modulated in terms of adhesion formation to the surrounding tissue. It clearly shows the different healing stages in terms of histopathology and offers a suitable model regarding biomechanics because it exhibits similar biomechanics as the human flexor tendons of the hand.

Summary: The rabbit Achilles tendon full transection model can be used to study adhesion extent in a controlled way. It also mimics the biomechanics of human hand flexor tendons.

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.

Clinical evidence in the treatment of rotator cuff tears with hyaluronic acid

PURPOSE

the aim of this quantitative review is to document potential benefit and adverse effects of hyaluronic acid (HA) injection into the shoulder with rotator cuff tears.

METHODS

a systematic literature search was performed in english PubMed, Medline, Ovid, Google Scholar and Embase databases using the combined key words "hyaluronic acid", "rotator cuff tear", "hyaluronate", "shoulder", "viscosupplementation", with no limit regarding the year of publication. Articles were included if they reported data on clinical and functional outcomes, complications in series of patients who had undergone HA injection for management of rotator cuff tears. Two Authors screened the selected articles for title, abstract and full text in accordance with predefined inclusion and exclusion criteria. The papers were accurately analyzed focusing on objective rating scores reported.

RESULTS

a total of 11 studies, prospective, 7 were randomized were included by full text. A total of 1102 patients were evaluated clinically after different HA injection compare with corticosteroid injection, physically therapies, saline solution injection and control groups. The use of HA in patients with rotator cuff tears improve VAS and functional score in all trials that we have analyzed.

CONCLUSION

intra-articular injection with HA is effective in reducing pain and improving function in shoulder with rotator cuff tears and without severe adverse reaction.

LEVEL OF EVIDENCE

Level I.

Rehabilitation following zone II flexor tendon repairs

Ongoing clinical and basic research has improved understanding of flexor tendon mechanics and physiology for surgical repair and rehabilitation after a zone II flexor tendon repair. Yet, the ideal surgical repair technique that includes sufficient strength to allow safe immediate active motion of the finger, without excessive repair stiffness, bulk or rough surfaces resulting in excessive resistance to flexion, does not exist. After optimizing the repair, the surgeon and therapist team must select a rehabilitation plan that protects the repair but helps to maintain tendon gliding. There are 3 types of rehabilitation programs for flexor tendon repairs: delayed mobilization, early passive mobilization, or an early active mobilization. No guideline for rehabilitation should be followed exactly. Many factors influence therapy decisions, including repair technique, associated tendon healing, passive versus active range of motion, edema, and tendon adhesions. These factors can assist in guiding rehabilitation progression and promote functional range of motion, safely mobilize the repaired tendon(s) and prevent gapping, rupture, and adhesions.

Adeno-associated virus-2-mediated TGF-β1 microRNA transfection inhibits adhesion formation after digital flexor tendon injury

Adhesion formation after digital flexor tendon injury greatly affects gliding function of the tendon, which is a major clinical complication after hand surgery. Transforming growth factor beta 1 (TGF-β1) has a critical role in adhesion formation during tendon healing. Persistent regulation of TGF-β1 through application of microRNA (miRNA) specifically inhibiting the function of TGF-β1 (TGF-β1-miRNA) holds promise for treatment of such a complication. Adeno-associated virus (AAV) was used to transfer TGF-β1-miRNA to the chicken digital flexor tendons, which had been injured and surgically repaired. Four doses of AAV2-TGF-β1-miRNA (2 × 10¹¹, 2 × 10¹⁰, 2 × 10⁹ and 2 × 10⁸ vector genomes (vg)) were used to determine the transfection efficiency. At postoperative 3 weeks, we found a positive correlation between the administered AAV2-TGF-β1-miRNA doses and transfection efficiency. The transfection rate ranged from 10% to 77% as the doses increased. Production of TGF-β1 protein in the tendons decreased on increasing vector dosage. When 2 × 10¹¹ and 2 × 10¹⁰) vg were injected into the tendon, gliding excursion of the repaired tendon and work of flexion of chicken toes were significantly increased and adhesion score decreased 6 and 8 weeks later, indicating the improvement of tendon gliding and decreases in adhesion formations. However, the ultimate strength of the tendons transfected at the dose of 2 × 10¹⁰ vg was 12-24% lower than that of the control tendons. The results of this study demonstrate that application of TGF-β1-miRNA had a mixed impact on tendon healing: adhesion around the tendon is reduced but strength of the tendon healing is adversely affected. Future studies should aim at maintaining the beneficial effects of reducing tendon adhesions, while eliminating the adverse effects of decreasing the healing strength.

Surgical adhesive BioGlue™ does not benefit tendon repair strength: an ex vivo study

Surgical adhesives are useful supplements in surgery, but their benefit in tendon repair is uncertain. The purpose of this study was to evaluate the effect of BioGlue™ on strength of flexor tendon repair. A total of 60 porcine flexor tendons were divided into three groups. In group one, a conventional core and peripheral suture repair was used. In group two, a core suture and BioGlue™ were used. In group three, a conventional core and peripheral suture repair and BioGlue™ were used. We performed static and cyclic axial load testing and measured diameter of the repair site. We found that BioGlue™ did not improve the tensile strength when added to a core and peripheral suture and that there was an increase in bulk at the repair site. We conclude that BioGlue™ application cannot replace a peripheral suture as tensile strength significantly decreases without a peripheral suture, and it does not benefit a tendon already repaired with a core and peripheral suture.

LEVEL OF EVIDENCE

n/a.

In vivo flexor tendon forces generated during different rehabilitation exercises

We measured in vivo forces in the flexor digitorum profundus and the flexor digitorum superficialis tendons during commonly used rehabilitation manoeuvres after flexor tendon repair by placing a buckle force transducer on the tendons of the index finger in the carpal canal during open carpal tunnel release of 12 patients. We compared peak forces for each manoeuvre with the reported strength of a flexor tendon repair. Median flexor digitorum profundus force (24 N) during isolated flexor digitorum profundus flexion and median flexor digitorum superficialis force (13 N) during isolated flexor digitorum superficialis flexion were significantly higher than during the other manoeuvres. Significantly higher median forces were observed in the flexor digitorum superficialis with the wrist at 30° flexion (6 N) compared with the neutral wrist position (5 N). Median flexor digitorum profundus forces were significantly higher during active finger flexion (6 N) compared with place and hold (3 N). Place and hold and active finger flexion with the wrist in the neutral position or tenodesis generated the lowest forces; isolated flexion of these tendons generated higher forces along the flexor tendons.

LEVEL OF EVIDENCE

III (controlled trial without randomization).

Improving results of flexor tendon repair and rehabilitation

BACKGROUND

The global time and effort attributed to improving outcomes in the management of flexor tendon injury are large, but the degree of advancement made over the past 50 years is relatively small. This review examines the current perceived wisdom in this field and aims to explore the limitations to the authors' understanding of the tendon healing process, examining how this may be a factor that has contributed to the authors' modest progress in the field.

METHODS

The authors critically evaluate the sum of laboratory and clinical literature on the topic of zone II flexor tendon management that has guided their practice and provide evidence to support their methods.

RESULTS

The review highlights some of the key developments over the years and assesses their influence on changing current practice. It also highlights recent innovations, which have the potential to influence flexor tendon outcomes by altering the surgical approach, techniques, and rehabilitation regimens. Future innovations in the field will also be discussed to examine their potential in expanding the development in the management of flexor tendon injury.

CONCLUSIONS

A better understanding of flexor tendon biology will allow progress in developing new therapies for flexor tendon injuries; however, there are as yet few real breakthroughs that will dramatically change current practice.

[Primary flexor tendons repair in zone 2]

Primary flexor tendon repair is still challenging even in the most experienced hands. With atraumatic surgery, the goal is to suture the tendon in a way that it will be strong enough to allow for tendon gliding without the risk of rupture or adhesions during the 12 weeks needed for the tendon to heal. After reviewing the zone 2 anatomy, the authors describe the state of art for flexor tendon repair along with their personal preferences. Although suture methods and postoperative rehabilitation programs are not universal, most specialized teams now use multistrand suturing techniques with at least 4 stands along with protected and controlled early active mobilization. Although the published rates of failure of the repair or postoperative adhesions with stiffness have decreased, these complications are still a concern. They will continue to pose a challenge for scientists performing research into the mechanics and biology of flexor tendon repairs, especially in zone 2.

Update on Zone II Flexor Tendon Injuries

Flexor tendon repair in zone II is particularly challenging because tendon gliding must be restored within a tight fibro-osseous sheath while minimizing the formation of adhesions in surrounding tissues. Meticulous surgical technique using a multistrand core suture and a peripheral suture is needed to produce a tendon that is strong enough to withstand early mobilization. Mechanical strength increases with the number of strands crossing the repair, regardless of the core suture configuration. Early mobilization after flexor tendon repair enhances the strength of the repair and decreases the risk of adhesions and joint stiffness. Satisfactory results have been achieved with either early passive or early active motion rehabilitation protocols; therefore, the choice of postoperative rehabilitation program is at the discretion of the surgeon. Factors such as repair integrity, concurrent injuries, and anticipated patient compliance should be considered in the decision-making process.

Prevention of peritendinous adhesions using an electrospun DegraPol polymer tube: a histological, ultrasonographic, and biomechanical study in rabbits

Purpose. One of the great challenges in surgical tendon rupture repair is to minimize peritendinous adhesions. In order to reduce adhesion formation, a physical barrier was applied to a sutured rabbit Achilles tendon, with two different immobilization protocols used postoperatively. Methods. Thirty New Zealand white rabbits received a laceration on the Achilles tendon, sutured with a 4-strand Becker suture, and half of the rabbits got a DegraPol tube at the repair site. While fifteen rabbits had their treated hind leg in a 180° stretched position during 6 weeks (adhesion provoking immobilization), the other fifteen rabbits were recasted with a 150° position after 3 weeks (adhesion inhibiting immobilization). Adhesion extent was analysed macroscopically, via ultrasound and histology. Inflammation was determined histologically. Biomechanical properties were analysed. Results. Application of a DegraPol tube reduced adhesion formation by approximately 20%—independently of the immobilization protocol. Biomechanical properties of extracted specimen were not affected by the tube application. There was no serious inflammatory reaction towards the implant material. Conclusions. Implantation of a DegraPol tube tightly set around a sutured tendon acts as a beneficial physical barrier and prevents adhesion formation significantly—without affecting the tendon healing process.

IFSSH Flexor Tendon Committee report 2014: from the IFSSH Flexor Tendon Committee (Chairman: Jin Bo Tang)

Hand surgeons continue to search for the best surgical flexor tendon repair and treatment of the tendon sheaths and pulleys, and they are attempting to establish postoperative regimens that fit diverse clinical needs. It is the purpose of this report to present the current views, methods, and suggestions of six senior hand surgeons from six different countries - all experienced in tendon repair and reconstruction. Although certainly there is common ground, the report presents provocative views and approaches. The report reflects an update in the views of the committee. We hope that it is helpful to surgeons and therapists in treating flexor tendon injuries.