The future of flexor tendon surgery

Use of Silicone Tubes as Antiadhesion Devices in a Modified Two-Stage Flexor Tendon Reconstruction in Zone II: A Retrospective Study

PURPOSE

This study aimed to assess the outcome of a modified two-stage flexor tendon reconstruction using silicone tubes as antiadhesion devices while performing simultaneous tendon grafting.

METHODS

From April 2008 to October 2019, 16 patients (21 fingers) with zone II flexor tendon injuries, who sustained failed tendon repair or neglected tendon laceration, were treated by a modified two-stage flexor tendon reconstruction. The first stage of treatment comprised flexor tendon reconstruction with interposition of silicone tubes to minimize fibrosis and adhesion around the tendon graft; the second stage of treatment comprised silicone tube removal under local anesthesia.

RESULTS

The patient median age was 38 (range, 22-65) years. After a median follow-up period of 14 (range, 12-84) months, the median total active motion (TAM) of fingers was 220° (range, 150-250°). Excellent and good TAM ratings were identified in 71.4%, 76.2%, and 76.2% according to the Strickland, modified Strickland, and American Society for Surgery of the Hand (ASSH) evaluation systems, respectively. At follow-up, complications included superficial infections in two fingers of one patient whose silicone tube was removed 4 weeks postoperatively. The most common complication was a flexion deformity of the proximal interphalangeal joint (four fingers) and/or distal interphalangeal joint (nine fingers). The rate of failed reconstruction was higher in patients with preoperative stiffness and infection.

CONCLUSIONS

Silicone tubes are suitable antiadhesion devices, and the modified two-stage flexor tendon reconstruction technique is an alternative procedure with a shorter rehabilitation period for complicated flexor tendon injury, compared with current popular reconstructions. Preoperative stiffness and postoperative infection may compromise the final clinical outcome.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Patient outcomes and costs after isolated flexor tendon repairs of the hand

BACKGROUND

Acute flexor tendon injuries are challenging injuries for patients, surgeons, and therapists alike. There is ongoing debate about the optimal timing and amount of therapy after these injuries.

PURPOSE

We sought to investigate the relationship between hand therapy utilization and reoperation rates after flexor tendon repair and quantify reoperation rates and costs associated with flexor tendon repair. We hypothesize there will be an inverse relationship between the number of hand therapy visits and later reoperation rates and a positive correlation between reoperation rates and total cost of care.

STUDY DESIGN

A retrospective cohort study of patients undergoing primary flexor tendon repair was pursued.

METHODS

A commercially available database was utilized to access insurance claims data for 20.9 million patients in the US from 2007 to 2015. Patients undergoing primary flexor tendon repair were included and followed for one year. Patients with fractures, vascular injuries, or digit replantation were excluded. We studied post-operative rehabilitation utilization, reoperation rates, and costs. Chi-Square tests and multivariable logistic regressions were used to assess the relationship between therapy utilization and reoperation rates and costs.

RESULTS

The one-year reoperation rate was 11.4 percent at a median time of 100.0 days amongst 1,129 patients undergoing primary tendon repair. In multivariable analysis, age between 30 and 59, male sex, and utilization of over 21 therapy sessions were associated with increased odds of reoperation. Mean insurance reimbursement one year following primary flexor repair was $14,533 per patient but $27,870 if patients went on to reoperation.

CONCLUSION

Continued therapy utilization after primary flexor tendon repair is an independent predictor of reoperation need. These findings may help surgeons counsel patients who require a large number of visits after flexor tendon repair on when to revisit surgical options.

Should we think about wrist extensor after flexor tendon repair?

OBJECTIVE

To evaluate the activity of wrist extensor muscle, correlating with wrist motion during gripping after flexor tendon repair.

DESIGN

Cross-sectional clinical measurement study.

SETTING

Laboratory for biomechanics and rehabilitation.

SUBJECTS

A total of 11 patients submitted to rehabilitation by early passive motion of the fingers with wrist flexion position were evaluated after 8 weeks of fingers flexor tendon repair and 11 healthy volunteers, all ranging from 20 to 37 years of age.

INTERVENTION

Volunteers performed an isometric standardized gripping task.

MAIN MEASURES

We used electrogoniometry to analyze wrist range of motion and surface electromyography, considering 100% maximum voluntary contraction to represent the amplitude of electromyographic activity of the extensor carpi radialis and flexor digitorum superficialis.

RESULTS

Patients with flexor tendon repair showed co-activation deficit between wrist extensor (extensor carpi radialis) and flexor finger muscles (flexor digitorum superficialis) during gripping in the intermediate phase of rehabilitation, despite some recovering mobility for wrist extension (p ≤ 0.05). A moderate correlation between range of motion and extensor carpi radialis was present only for injured group (r = 0.32). Total active motion score, which represents finger active excursion, was regular or poor in 65% of cases, all with nerve repair associated.

CONCLUSION

Wrist extensors have an important synergist role at handgrip, although some imbalance can be present after flexor tendon repair. These preliminary findings suggest that emphasis could be directed to add synergistic wrist motion in rehabilitation protocols after flexor tendon repair. Future studies with early active rehabilitation are necessary.

Cell migration after synovium graft interposition at tendon repair site

BACKGROUND

We have recently reported that interpositional synovium grafts from tendon sheath have a potential to accelerate tendon healing when implanted at the repair site. The purpose of this study was to investigate the effect of orientation of the synovium after synovium graft transplantation, by comparing the ability of cells from the visceral and parietal surfaces to migrate into the tendon in a canine tissue culture model.

METHODS

The synovium graft was placed within a complete tendon laceration, with either the visceral or parietal surface facing the proximal end of the lacerated tendon. The number of migrating cells was quantified by a cell migration assay. Qualitative immunohistochemistry and confocal laser microscopy were also used at day 10.

RESULTS

Many labeled synovial cells were observed within the tendon to which the visceral surface of the synovium graft was facing. Migrated cells were also observed on the parietal side, but there were fewer cells compared to visceral surface cells. Migrating cells all expressed α-smooth muscle actin.

CONCLUSION

We found that graft orientation affected cell migration. Whether this finding has clinical significance awaits in vivo study.

Managing the injured tendon: current concepts

Despite advances in understanding of the mechanical aspects of tendon management with improved suture technique and early stress application with postoperative therapy, clinical results remain inconsistent after repair, especially within the synovial regions. Complementary research to enhance the intrinsic pathway of healing, suppress the extrinsic pathway of healing, and manipulate frictional resistance to tendon gliding is now the focus of current basic science research on tendons. In the future, application of these new biologic therapies may increase the "safety zone" (or tolerance for load and excursion without dysfunctional gapping) as therapists apply stress to healing tendons and may alter future rehabilitation protocols by allowing greater angles of motion (and thus tendon excursion), increased external load, and decreased time in protective orthoses (splints). However, at this time, the stronger repair techniques and the application of controlled stress remain the best and most well-supported intervention after tendon injury and repair in the recovery of functional tendon excursion and joint range of motion. The hand therapist's role in this process remains a critical component contributing to satisfactory outcomes.

The effect of suture coated with mesenchymal stem cells and bioactive substrate on tendon repair strength in a rat model

PURPOSE

Exogenously administered mesenchymal stem cells and bioactive molecules are known to enhance tendon healing. Biomolecules have been successfully delivered using sutures that elute growth factors over time. We sought to evaluate the histologic and biomechanical effect of delivering both cells and bioactive substrates on a suture delivery vehicle in comparison with sutures coated with bioactive substrates alone.

METHODS

Bone marrow-derived stem cells were harvested from Sprague-Dawley rat femurs. Experimental cell and substrate-coated, coated suture (CS) group sutures were precoated with intercellular cell adhesion molecule 1 and poly-L-lysine and seeded with labeled bone marrow-derived stem cells. Control (substrate-only [SO] coated) group sutures were coated with intercellular cell adhesion molecule 1 and poly-L-lysine only. Using a matched-paired design, bilateral Sprague-Dawley rat Achilles tendons (n = 105 rats) were transected and randomized to CS or SO repairs. Tendons were harvested at 4, 7, 10, 14, and 28 days and subjected to histologic and mechanical assessment.

RESULTS

Labeled cells were present at repair sites at all time points. The CS suture repairs displayed statistically greater strength compared to SO repairs at 7 days (12.6 ± 5.0 N vs 8.6 ± 3.7 N, respectively) and 10 days (21.2 ± 4.9 N vs 16.4 ± 4.8 N, respectively). There was no significant difference between the strength of CS suture repairs compared with SO repairs at 4 days (8.1 ± 5.1 N vs 6.6 ± 2.3 N, respectively), 14 days (22.8 ± 7.3 N vs 25.1 ± 9.7 N, respectively), and 28 days (40.9 ± 12.4 N vs 34.6 ± 15.0 N, respectively).

CONCLUSIONS

Bioactive CS sutures enhanced repair strength at 7 to 10 days. There was no significant effect at later stages.

CLINICAL RELEVANCE

The strength nadir of a tendon repair occurs in the first 2 weeks after surgery. Bioactive suture repair might provide a clinical advantage by jump-starting the repair process during this strength nadir. Improved early strength might, in turn allow earlier unprotected mobilization.

The epidemiology of reoperation after flexor tendon repair

PURPOSE

To describe the incidence of reoperation and the demographic factors that may be associated with reoperation after flexor tendon repair.

METHODS

Using a New York statewide hospital administrative database covering an 8-year period, we examined unique patient discharges with an index procedure of flexor tendon repair for reoperation (re-repair or tenolysis). We compared the age, sex, race, and insurance type by reoperation status using standard univariate statistics and multivariate regression analysis. We performed trend analysis using the Cochran-Armitage trend test.

RESULTS

From 1998 to 2005, there were 5,229 flexor tendon repairs with a frequency of reoperation of 6%; of these, 91% were in the first year after the primary procedure. Those who underwent reoperation were significantly older than those who did not undergo reoperation. Patients with workers' compensation were 63% more likely to undergo reoperation than those with other forms of insurance. Patients who had concomitant nerve repair during the index procedure were 26% less likely to undergo reoperation. The rate of reoperation did not change during the study period.

CONCLUSIONS

These results may be useful in shaping research agendas to evaluate sociodemographic factors contributing to reoperations.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic II.

Complications after flexor tendon repair: a systematic review and meta-analysis

PURPOSE

Although outcomes after flexor tendon repair have reportedly improved with modern treatment, complications are common. The purpose of this study was to determine the incidence of these complications and the potential contributory factors within the published literature.

METHODS

We performed a systematic review of the available literature to identify publications in which patients with flexor tendon ruptures were surgically treated. We extracted demographics, zone of injury, core suture technique (only modified Kessler or a combination of techniques), use of epitendinous suture, and date of publication (before or after January 1, 2000). We excluded articles if they did not report information on reoperation, rupture, or adhesions. We used unadjusted pooled meta-analysis to report the incidence of complications, and meta-regression to describe the potential contributory factors for each complication while controlling for age, gender, and zone of injury.

RESULTS

Unadjusted meta-analysis revealed rates of re-operation of 6%, rupture of 4%, and adhesions of 4%. Meta-regression analysis of 29 studies showed that core suture technique or use of an epitendinous suture does not influence rupture. However, the presence of an epitendinous suture decreases re-operation by 84%. Adhesion development is 57% lower when the modified Kessler technique is used. The incidence of complications did not vary with publication date.

CONCLUSIONS

The published literature supports use of the modified Kessler repair technique with an epitendinous suture to minimize complications. Although complication rates are low, our data suggest that there has been no definitive improvement in reported complications before and after 2000.

Avulsion injuries of the flexor digitorum profundus tendon

Avulsions of the flexor digitorum profundus tendon may involve tendon retraction into the palm and fractures of the distal phalanx. Although various repair techniques have been described, none has emerged as superior to others. Review of the literature does provide evidence-based premises for treatment: multi-strand repairs perform better, gapping may be seen with pullout suture-dorsal button repairs, and failure because of bone pullout remains a concern with suture anchor methods. Clinical prognostic factors include the extent of proximal tendon retraction, chronicity of the avulsion, and the presence and size of associated osseous fragments. Patients must be counseled appropriately regarding anticipated outcomes, the importance of postoperative rehabilitation, and potential complications. Treatment alternatives for the chronic avulsion injury remain patient-specific and include nonsurgical management, distal interphalangeal joint arthrodesis, and staged reconstruction.

Viability and proliferation of pluripotential cells delivered to tendon repair sites using bioactive sutures--an in vitro study

PURPOSE

We evaluated the fate of pluripotential stem cells adherent to a suture carrier after being passed through tendon tissue in vitro.

METHODS

FiberWire suture segments were coated with poly-L-lysine (PLL) and a 2 × 10(6) C3H10T1/2 (a mouse embryo pluripotential cell line) cell suspension. The sutures were incubated for 7 days, passed through two 1-cm segments of acellularized rabbit Achilles tendons and tied (horizontal mattress). The repairs were frozen and sectioned (6 μm). The sections were stained with 4',6-diamidino-2-phenylindole and a live/dead viability/cytotoxicity (calcein/ethidium homodimer) kit and examined with fluorescent microscopy to evaluate cell presence and viability. Alamar Blue was used in parallel to assess metabolic activity.

RESULTS

PLL-coated sutures showed a 3-fold increase in fluorescence when compared with the phosphate-buffered saline-coated controls. At day 3, fluorescence was 2.2 times greater. At day 5, a 2-fold increase was found, and at day 8 there was no significant difference in values. Furthermore, after delivery of the cells into tendon, fluorescence readings for the samples (n = 19) showed 9450 compared with the positive control at 21,218. At 96 hours the mean was 27,609 compared with 34,850 for the positive control. The difference in fluorescence means at 48 hours and 96 hours were significant (p < .001). Live-dead and DAPI staining confirmed the presence of live cells at the tendon repair site.

CONCLUSIONS

Sutures seeded with pluripotential embryonic cells deliver cells to a tendon repair site. The cells deposited at the repair site survive the trauma of passage and remain metabolically active, as seen in staining and metabolic assay studies. Use of bioactive sutures leads to repopulation of the acellular zone surrounding sutures within the tendon.

Effects of a lubricin-containing compound on the results of flexor tendon repair in a canine model in vivo

BACKGROUND

Tendon surface modification with a synthetic biopolymer, carbodiimide-derivatized hyaluronic acid and gelatin with the addition of lubricin (CHL), has been shown to reduce gliding resistance after tendon repair in an in vitro model. The purpose of the study was to investigate whether CHL would reduce adhesion formation and improve digital function after flexor tendon repair in a canine model in vivo.

METHODS

Sixty dogs were randomly assigned to either a biopolymer-treated group (n = 30) or an untreated control group (n = 30). The second and fifth flexor digitorum profundus tendons from each dog were lacerated fully at the zone-II area and then repaired. Passive synergistic motion therapy was started on the fifth postoperative day and continued until the dogs were killed on day 10, day 21, or day 42. The repaired tendons were evaluated for adhesions, normalized work of flexion, gliding resistance, repair strength, stiffness, and histological characteristics.

RESULTS

The normalized work of flexion of the repaired tendons treated with CHL was significantly lower than that of the non-CHL-treated repaired tendons at all time points (p < 0.05), and the prevalence of severe adhesions was also significantly decreased in the CHL-treated tendons at day 42 (p < 0.05). However, the repair failure strength and stiffness of the CHL-treated group were also significantly reduced compared with those of the control group at days 21 and 42 (p < 0.05) and the rate of tendon rupture was significantly higher in the treated group than in the control group at day 42 (p < 0.05).

CONCLUSIONS

Treatment with the lubricin-containing gel CHL appears to be an effective means of decreasing postoperative flexor tendon adhesions, but it is also associated with some impairment of tendon healing. Future studies will be necessary to determine if the positive effects of CHL on adhesion formation can be maintained while reducing its adverse effect on the structural integrity of the repaired tendon.

Effectiveness of microRNA in Down-regulation of TGF-beta gene expression in digital flexor tendons of chickens: in vitro and in vivo study

PURPOSE

Transforming growth factor (TGF)-beta is considered to be responsible for the formation of scars such as adhesions around healing digital flexor tendons. We proposed to deliver microRNAs (miRNAs) to silence expression of the TGF-beta1 gene and to investigate the effectiveness of miRNAs in down-regulation of the TGF-beta1 gene in vitro and in vivo.

METHODS

We designed and engineered 4 miRNAs according to genetic sequences of chicken TGF-beta1. Four plasmid vectors harboring the respective engineered miRNAs and 1 control vector were constructed. We transfected 30 wells of cultured tenocytes with these vectors and harvested them 48 hours later. The gene expression levels were quantified using real-time polymerase chain reactions. Subsequently, the miRNA that most effectively silenced TGF-beta gene in vitro was tested on 25 chickens in vivo. The miRNA and control vectors were injected into the injured tendons, respectively. At 1 and 6 weeks after surgery, the tendons were analyzed for gene expression and protein production.

RESULTS

In both in vitro and in vivo settings, delivery of miRNA to the tendon substantially down-regulated expression of the TGF-beta gene but did not affect expression of the collagen I gene. In the healing tendon, TGF-beta gene expression was significantly down-regulated by 50% to 60% at 1 and 6 weeks. At 6 weeks, the collagen III gene expression was significantly down-regulated by 55% at 6 weeks and the connective tissue growth factor gene was significantly down-regulated by 25%. At 6 weeks, TGF-beta protein was substantially decreased.

CONCLUSIONS

MicroRNA significantly down-regulates expression of the TGF-beta in vitro and in vivo. Application of miRNA did not down-regulate expression of the collagen I, but downregulated the collagen III gene. Application of miRNA treatment to modulate TGF-beta expression holds great promise in preventing tendon adhesion formation.

Bioactive sutures for tendon repair: assessment of a method of delivering pluripotential embryonic cells

PURPOSE

Pluripotential embryonic cells may be seeded onto sutures intended for tendon repair. These cells may be influenced to adhere to suture material using adhesion substrates, and furthermore, these cells may remain in culture attached to those sutures. These cell-impregnated sutures may be useful for promoting healing of tendon repairs.

METHODS

Ten-centimeter segments of 4-0 sutures (FiberWire) were coated overnight with 10 microg/mL fibronectin, 10 microg/mL poly-l-lysine, or phosphate-buffered saline. The sutures were placed in dishes and covered with a suspension of C3H10T1/2 cells at concentrations of 1 x 10(6), 2 x 10(6), or 4 x 10(6) cells for 24 hours. The sutures were then placed into low adhesion polypropylene tubes with Dulbecco's modified Eagle's medium and 10% fetal bovine serum for 7 days. The presence of viable cells on these sutures was assessed by the colorimetric Alamar blue cell proliferation assay. Spectrophotometry was used to quantify the relative amount of cell proliferation across the experimental groups. The sutures were also visually inspected using phase-contrast light microscopy.

RESULTS

Our results show that at all seeding densities (1 x 10(6), 2 x 10(6), and 4 x 10(6) cells), the suture segments coated with poly-l-lysine and fibronectin showed a significant increase in C3H10T1/2 cell adhesion. Coating the suture with poly-l-lysine increased the adherent cell number to 17% of the initial seeding concentration compared with 2% for the control. Fibronectin coating increased the number of adherent viable cells present to 6.6%.

CONCLUSIONS

Pluripotential embryonic cells may be seeded onto sutures, adhere, and survive in culture. Coating sutures with poly-l-lysine and fibronectin offers significant improvement in retention of viable cells. This technique may be a useful adjunct for future tendon healing studies.

Secondary flexor tendon reconstruction, a review

As techniques have improved, primary repair of flexor tendon lacerations, including zone II injuries, have become more common. Secondary reconstruction, whether in 1 or 2 stages, remains an important and useful technique for the treatment of these injuries. Current indications and methods, including delayed treatment and 1-stage and 2-stage reconstruction, are reviewed. Future directions of tendon reconstruction are also discussed.

[The influence of duration of Kleinert immobilization on the functional recovery of primarly reconstructed flexor tendons in children and adult patients]

Flexor tendon repair in the hand is very often complicated by the formation of peritendinous adhesions that result in loss of normal tendon gliding, digital stiffnes and functional disability. While stability is critical for a successful tendon repair, mobility is also important, as motion of the repaired tendon decreases the formation of postoperative adhesions and increases the strength of the repair. Immobilization and its duration, can ensure the integrity of the repair but can also lead to scaring, stiffness, and joint contractures. This study included 20 children and 39 adult patients, in the period from January 2000 to April 2003., with flexor tendon ruptures of the hand. Tendons were primary repaired using direct tennoraphy, and postoperately patients were treated with Kleinert dynamic imobilization. The aim of this study was to investigate the influence of the duration of the dynamic immobilization on successful postoperative functional recovery, separately in children and adult patients. Research in this area has been directed at achieving the optimal balance between stability and mobility, without compromising one for the other.