Aggressive active mobilization following zone II flexor tendon repair using a two-strand heavy-gauge locking loop technique

Flexor tendon rehabilitation in the 21st century: A systematic review

STUDY DESIGN

Systematic review.

INTRODUCTION

The rehabilitation of patients following flexor tendon injury has progressed from immobilization to true active flexion with the addition of wrist motion over the last 75 years.

PURPOSE OF THE STUDY

This review specifically intended to determine whether there is evidence to support one type of exercise regimen, early passive, place and hold, or true active, as superior for producing safe and maximal range of motion following flexor tendon repair.

METHODS

The preferred reporting items for systematic review and meta-analysis (PRISMA-P 2015) checklist was utilized to format the review. Both reviewers collaborated on all aspects of the research, including identifying inclusion/exclusion factors, search terms, reading and scoring articles, and authoring the paper. Articles were independently scored by each reviewer using the Structured Effectiveness Quality Evaluation Scale (SEQES).

RESULTS

A total of nine intervention studies that included a rehabilitative comparison group were systematically reviewed: one pediatric, four comparing passive flexion protocols to place and hold flexion, and four comparing true active flexion to passive and/or place and hold flexion.

DISCUSSION

This review provides moderate to strong evidence that place and hold exercises provide better outcomes than passive flexion protocols for patients with two to six-strand repairs. The studies included in this review suffered from methodological limitations including short timeframes for follow-up, unequal group distribution, and limited attention to repair site strength.

CONCLUSIONS

Based on a lack of superior benefits following true active motion regimens, there is not sufficient evidence to support true active motion as an effective or preferable choice for flexor tendon rehabilitation at this time.

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.

Reinforcement of the Flexor Tendon Repair Using Human Amniotic MembraneA Biomechanical Evaluation Using the Modified Kessler Method of Tendon Repair

BACKGROUND

Human amniotic membrane is used to prevent peritendinous adhesions after tendon injuries. This study compares the mechanical properties of modified Kessler repairs and modified Kessler repairs strengthened using multiple layers of human amniotic membrane.

METHODS

Twenty flexor digitorum profundus tendons of sheep forelimbs were sutured by the two-strand modified Kessler technique (group A) and by the two-strand modified Kessler repair reinforced with multiple layers of human amniotic membrane (group B). To assess the mechanical performance of the repairs, tendons were subjected to a linear noncyclic load-to-failure test using a material testing machine. Outcome measures included ultimate forces and the mode of failure.

RESULTS

The mean ± SD value of the failure strength was 34.6 ± 1.64 N for group A and 50.6 ± 5.60 N for group B. The reinforced repair provided a significantly higher ultimate load compared with the nonreinforced group (P < .001). All of the specimens failed due to suture breakage at the repair site.

CONCLUSIONS

The results of this study show that the modified Kessler repair can be reinforced effectively with human amniotic membrane.

Epidemiology of Flexor Tendon Injuries of the Hand in a Northern Finnish Population

Background:

Flexor tendon injuries cause significant morbidity in working-age population. The epidemiology of these injuries in adult population is not well known. The aim of this study was to describe the epidemiology of flexor tendon injuries in a Northern Finnish population.

Material and Methods:

Data on flexor tendon injuries, from 2004 to 2010, were retrieved from patient records from four hospitals, which offer surgical repair of the flexor tendon injuries in a well-defined area in Northern Finland. The incidence of flexor tendon injury as well as the gender-specific incidence rates was calculated. Mechanism of injury, concomitant nerve injuries, and re-operations were also recorded.

Results:

The incidence rate of flexor tendon injury was 7.0/100,000 person-years. The incidence was higher in men and inversely related to age. The most common finger to be affected was the fifth digit. In 37% of injuries also digital nerve was affected. The most common finger to have simultaneous digital nerve injury was the thumb.

Conclusion:

Flexor tendon laceration is a relatively rare injury. It predominantly affects working-aged young males and frequently includes a nerve injury, which requires microsurgical skills from the surgeon performing the repair. This study describes epidemiology of flexor tendon injuries and therefore helps planning the surgical and rehabilitation services needed to address this entity.

Usefulness of braided polyblend polyethylene suture material for flexor tendon repair in zone II by the side-locking loop technique

Flexor tendon injuries in zone II were treated in 14 fingers of 13 patients with our method. Firstly, a 2-strand core suture was made by the side-locking loop technique using a USP 2-0-sized braided polyblend polyethylene suture, then 7-strand peripheral cross-stitches were added using a USP 5-0-sized monofilament nylon suture. Post-operative exercises included passive flexion and extension without external fixation on the next day of surgery. Average follow-up observation period was 18 months. As results, the Strickland method of assessment for surgical outcome showed excellent in eight digits and good in five digits, though there was a poor outcome in one digit. Our suture method enabled early post-operative mobilisation exercise without using a splint, while preventing adhesion between the repaired tendon and peripheral tissues, which is considered to provide far greater ultimate tensile strength and a smaller gap at the sutured site than by the conventional method.

A systematic review of 2-strand versus multistrand core suture techniques and functional outcome after digital flexor tendon repair

PURPOSE

To determine published evidence to evaluate the hypothesis that multistrand techniques result in a poorer outcome than 2-strand techniques for digital flexor tendon repairs.

METHODS

A systematic review was undertaken to compare outcomes and rupture rates between 2-strand and multistrand core sutures in digital flexor zones 2 to 5. Outcome was measured by the American Society for Surgery of the Hand criteria, original or modified Strickland criteria, or Buck-Gramcko criteria.

RESULTS

A total of 1,878 patients (2,585 digits; 3,749 tendons) were included from the selected studies. Thirty-three studies reported 2-strand repairs and 15 reported multistrand repairs. Of the total tendon injuries, 59% were flexor digitorum profundus, 38% were flexor digitorum superficialis, and 2% were flexor pollicis longus. The pooled rupture rate was 3.9 per 100 digits. No significant difference was detected between 2-strand and multistrand repairs for outcomes by all measures or rupture rate.

CONCLUSIONS

Because of the wide variation in reporting of outcomes and study design on which this analysis was based, we cannot definitively confirm our hypothesis. We present the standards for outcomes as well as rupture rate for digital flexor tendon repair.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic III.

Flexor tendon repair rehabilitation protocols: a systematic review

PURPOSE

To systematically review various flexor tendon rehabilitation protocols and to contrast those using early passive versus early active range of motion.

METHODS

We searched PubMed and Cochrane Library databases to identify articles involving flexor tendon injury, repair, and rehabilitation protocols. All zones of injury were included. Articles were classified based on the protocol used during early rehabilitation. We analyzed clinical outcomes, focusing on incidence of tendon rupture and postoperative functional range of motion. We also analyzed the chronological incidence of published tendon rupture with respect to the protocol used.

RESULTS

We identified 170 articles, and 34 met our criteria, with evidence ranging from level I to level IV. Early passive motion, including both Duran and Kleinert type protocols, results included 57 ruptures (4%) and 149 fingers (9%) with decreased range of motion of 1598 tendon repairs. Early active motion results included 75 ruptures (5%) and 80 fingers (6%) with decreased range of motion of 1412 tendon repairs. Early passive range of motion protocols had a statistically significantly decreased risk for tendon rupture but an increased risk for postoperative decreased range of motion compared to early active motion protocols. When analyzing published articles chronologically, we found a statistically significant trend that overall (passive and active rehabilitation) rupture rates have decreased over time.

CONCLUSIONS

Analyzing all flexor tendon zones and literature of all levels of evidence, our data show a higher risk of complication involving decreased postoperative digit range of motion in the passive protocols and a higher risk of rupture in early active motion protocols. However, modern improvements in surgical technique, materials, and rehabilitation may now allow for early active motion rehabilitation that can provide better postoperative motion while maintaining low rupture rates.

Comparison of a multifilament stainless steel suture with FiberWire for flexor tendon repairs--an in vitro biomechanical study

Our goal was to investigate and compare the mechanical properties of multifilament stainless steel suture (MFSS) and polyethylene multi-filament core FiberWire in flexor tendon repairs. Flexor digitorum profundus tendons were repaired in human cadaver hands with either a 4-strand cruciate cross-lock repair or 6-strand modified Savage repair using 4-0 and 3-0 multifilament stainless steel or FiberWire. The multifilament stainless steel repairs were as strong as those performed with FiberWire in terms of ultimate load and load at 2 mm gap. This study suggests that MFSS provides as strong a repair as FiberWire. The mode of failure of the MFSS occurred by the suture pulling through the tendon, which suggests an advantage in terms of suture strength.

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.

LENGTHENING THE LOCKING LOOP REPAIR FOR ZONE 2 FLEXOR TENDON LACERATION AND PARTIAL LATERAL RELEASE OF THE TENDON SHEATH

The authors present the clinical outcomes of nine zone 2 flexor tendon repairs using a locking loop technique (i.e. the Modified Pennington technique). The locking loops were located approximately 10 mm away from the lacerated tendon ends to "lengthen" the locking loop repair, as experimentally and clinically recommended. The partial lateral release of the tendon sheath, including the A2 and/or A4 pulley, was performed not only to locate the sutures but also to allow a full range of motion of the repair without catching on the tendon sheath, as clinically recommended. All the patients were followed up for six months or more except for one. All digits were evaluated as excellent or good at the final follow-up by the original Strickland criteria. No rupture occurred and no bowstring of the flexor tendon was observed. The clinical outcomes of the current study indicate that "lengthening" the locking loop repair is effective for zone 2 flexor tendon repair and that the partial lateral release of the tendon sheath, including the A2 and/or A4 pulley, does not result in the bowstring of the flexor tendon.

Optimum suture material for locking technique in tendon repair: effects of suture friction in mobilization

BACKGROUND

The 2-strand side-locking loop technique allows secure locking formation easily, yielding maximum tensile force. However, not all suture materials are suitable for this technique.

METHODS

The bovine gastrocnemius tendons were transected and repaired end-to-end by the side-locking loop technique using USP2 braided polyblend, braided polyester, monofilament nylon, braided nylon, or monofilament absorbable polydioxanone sutures. A repetitive loading protocol from 10N to 100N was used, and the loading was repeated 10,000 times. In ruptured samples during the repetitive loading test, the number of loading was recorded. In samples which did not rupture, the ultimate tensile strength was measured after repetitive loading. After testing, ruptured sutures were examined microscopically. For comparison of ultimate tensile strength before and after repetitive loading, we performed a one-time loading test on samples which did not undergo the repetitive loading.

FINDINGS

With monofilament nylon, braided nylon, or monofilament absorbable polydioxanone, suture rupture occurred during repetitive loading. In contrast, no suture rupture occurred with braided polyblend or braided polyester. Microscopic observation showed abrasion of the surface in braided polyester, though the friction effects were not seen with braided polyblend. The mean ultimate tensile strength before and after repetitive loading was 395N and 399N, respectively, for braided polyblend. For braided polyester, they were 208N and 174N, respectively.

INTERPRETATION

Braided polyblend suture material has an excellent resistivity to friction and is suitable for the side-locking loop technique.

The longer pull-out suture as a transmission suture for early active motion of repaired flexor tendon at the proximal zone-2

OBJECTIVES

The purpose of the current study was to clinically evaluate the technique of longer pull-out suture as a transmission suture for early active motion after flexor tendon repair in the proximal zone-2.

METHOD

Eleven patients (eight adult male, two adult female and one child) with 19 proximal zone II flexor tendon lacerations were included. Mean age was 35 years. The patients were encouraged to perform active mobilization of the injured digits by themselves with full range of flexion from the first postoperative day. The pull-out suture was removed at the 8-10 weeks after the operation.

RESULTS

The mean follow-up was 39 months. The procedure was well tolerated by all of the patients. A patient of whom pull-out suture was traumatized and loosened at 6th week showed fair result. Two other patients with a history of blunt trauma were also found to have fair results. Overall 16 of the 19 digits were evaluated as excellent or good by the Strickland criteria.

CONCLUSION

The results of this method show that the longer pull-out suture technique as a transmission suture followed by early active mobilization is safe, has a low re-rupture rate and is easy to perform for proximal zone-2 flexor tendon injuries.

Optimally strong tendon repair using braided polyethylene strand: 2-strand heavy-gauge locking technique vs. multiple-strand technique

BACKGROUND

We conducted an in vitro study to investigate the strongest tensile force for tendon repair using a braided polyblend suture strand material, employing a 2-strand heavy-gauge side-locking loop technique, comparing it with other multiple-strand repair techniques.

METHODS

Using the United States Pharmacopeial Convention (USP) 2 and 5-sized braided polyblend strands, 3 repair techniques were evaluated after suturing transacted bovine gastrocnemius tendons: 2-strand side-locking loop, 4-strand Savage, and 6-strand Yoshizu-1 techniques. Ultimate tensile force and mode of failure at strand rupture were examined (n=5 for each combination).

FINDINGS

The ultimate tensile forces was observed with USP2-side-locking loop (mean 402 N), USP5-side-locking loop (mean 748 N), USP2-Savage (mean 552 N), and USP2-Yoshizu-1 Groups (mean 598 N). The USP5-side-locking loop Group had proportionally greater ultimate tensile force than the USP2-side-locking loop Group. However, with the number of strands doubled or tripled, resulting strengths were only 1.4 times or 1.5 times greater. The mode of failure was rupture at the locking loop portion in all side-locking loop Group samples, pull-through of the strand from the tendon in all Savage Group samples, and either pull-through of the strand from the tendon (40%) or rupture at the knot (60%) in the Yoshizu-1 Group samples.

INTERPRETATION

Greater numbers of strands do not achieve proportionally greater strong tensile force in the repaired tendon. When employing the side-locking loop technique for secured locking formation, the heavier strand yields markedly greater tensile force even with only 2 strands, and thus greater holding ability.

ICF components of corresponding outcome measures in flexor tendon rehabilitation - a systematic review

Background

The International Classification of Functioning, Disability and Health (ICF) delivers a holistic approach to health conditions. The objective of the present study is to provide an overview of flexor tendon rehabilitation outcome measures with respect to ICF components. Furthermore, it aims to investigate to which extent current assessments measure aspects of health according to these components primarily focussing on activity and participation.

Methods

A systematic literature review was conducted to identify all studies meeting the inclusion criteria. Studies were only included if they assessed more than body function and body structure and referred to the ICF components activity and participation. The outcome measures were analysed and their linkage to the ICF components were investigated to examine to which degree aspects of health outcome as defined by the ICF were considered.

Results

As anticipated, the application of outcome measures after flexor tendon repair is non conform. In many studies the emphasis still lies on physical impairment neglecting activity limitations and participation restrictions.

Aspects of health after flexor tendon repair could be assessed more adequately and cover patients' needs more sufficiently by choosing outcome measures which refer to all aspects of functioning.

Conclusion

The ICF can help to identify aspects of health which are not being considered. The ICF can help promote further development of adequate outcome measures including activity limitation and participation restrictions by targeting patient centred goals and respecting patients' needs.

Comparison of therapeutic activities with therapeutic exercises in the rehabilitation of young adult patients with hand injuries

PURPOSE

To compare the efficacy of therapeutic activities that mimick the activities of daily living with that of traditionally used therapeutic exercises in the management of injured hands in young adult patients.

METHODS

Thirty-six patients having functional loss due to hand injury were enrolled. Patients were allocated randomly into 2 groups. The study group included 20 patients, and the control group included 16 patients. For the control group, according to their impairments, an exercise program including passive, active assistive, and active range of motion and strengthening exercises in addition to physical modalities was applied for 2 sessions a day. For the study group, in addition to 1 session of the same program, a program composed of 25 activities that mimick activities of daily living (ADL) was applied for 1 session. Treatment continued for 3 weeks, 5 days a week. Then the patients were given a home program. After 2 months, patients were reevaluated.

RESULTS

Mean age for the patients was 23 years +/- 3. The time span from injury to surgery was a mean of 7 days +/- 5, and the mean period between the injury and the physical therapy was a mean of 102 days +/- 68. Grip strength, pinch strength, finger pulp-distal palmar crease distance, total active movement, range of opposition, range of abduction, Jebsen hand function test, and Disabilities of Arm, Shoulder, and Hand scores were obtained before treatment, after treatment, and 2 months after treatment. At final assessment, differences in improvements of all parameters were found to be statistically significant between the groups in favor of the study group.

CONCLUSIONS

Because of the complex anatomy, determination of the most appropriate treatment may not be easy in an injured hand. Our results showed that the therapeutic activities that mimick the ADL improve the functions of the hand more effectively. We suggest that the therapeutic activities that mimick the ADL may be more beneficial than the standard rehabilitation activities in the management of an injured hand.

Optimum location of knot for tendon surgery in side-locking loop technique

BACKGROUND

Although various tendon repair techniques have been reported to achieve stronger repair, suture failures tend to occur near the knot. We experimentally investigated whether the location of a single core suture knot affects the biomechanical properties of the repair.

METHODS

Transected bovine tendons (male Japanese black cattle, 24 months old) of the medial gastrocnemius (9-11 x 14-16 mm in diameter) were sutured with the side-locking loop technique using a USP2-sized polyethylene and polyester multifilament suture or polyester multifilament suture. The knot was made using 7 simple square ties (a surgeon's knot plus 5 ties) at three locations; on the loop, between the tendon stumps, or between the loops burying the knot in a tendon slit using a scalpel. A cyclical loading protocol from 10N to 100N was used and the loading was repeated 10,000 times.

FINDINGS

The gap was most decreased and the ultimate strength was most increased when the knot was located between the loops when using a polyethylene and polyester multifilament suture. Cross-sectional area of the tendon showed the ratio of the buried knot relative to the tendon was only 1.6-2.3%, and the polyethylene and polyester multifilament suture was very durable against frictional abrasion.

INTERPRETATION

We found that the knot between the loops, buried in the bovine tendon provided the optimum results.

Biomechanical differences resulting from the combination of suture materials and repair techniques

BACKGROUND

Many suture materials and repair techniques have been applied in clinical tendon surgery. However, no recommendation is available concerning the choice of suture materials and repair techniques except in a few experimental studies. The purpose of the current study is to show the biomechanical difference resulting from the combination of suture materials and repair techniques.

METHODS

The gastrocnemius tendons of 24-week-old cattle (diameter 14-16x9-11 mm) were repaired with application of a single locking, multiple locking, single grasping, or multiple grasping technique using a USP2 suture thread of either braided polyblend polyethylene, polyester, polydioxanone, or nylon. Therefore, a total of 16 combinations were made, with eight specimens for each combination. The specimen was set in an Instron tensiometer to measure the gap length after repetitive tensile loading 500 times (10-100 N).

RESULTS

The single locking technique using braided polyblend polyethylene provided the smallest gap (4.5+/-0.5 mm). Other techniques using the same material resulted in a large gap (10.0-11.8 mm). The polyester provided a relatively smaller gap length, irrespective of the repair technique (7.4-8.8 mm). Polydioxanone and nylon tended to result in a large gap (9.3-12.3 mm and 8.4-10.6 mm, respectively).

CONCLUSIONS

Mechanical properties of each tendon suture depended on the particular combination of suture materials and repair techniques. The combination of braided polyblend polyethylene and single locking technique provided the highest antigap strength.

Gliding Resistance of the Flexor Pollicis Longus Tendon after Repair: Does Partial Excision of the Oblique Pulley Affect Gliding Resistance?

BACKGROUND

After tendon repair, it is critical for the repair site to pass smoothly under the pulley edge to promote gliding and reduce the risk of adhesion or rupture. In this study, the authors assessed the effect of partial excision by "squaring off" the distal edge of the oblique pulley on the gliding resistance of the flexor pollicis longus tendon after repair in vitro.

METHODS

Gliding resistance of 10 human thumbs was measured directly with three different sequential conditions: intact flexor pollicis longus tendon with intact A1 and oblique pulleys (group A), intact pulleys after repair of the tendon (group B), and after repair and excision of the distal triangular part (squaring off) of the oblique pulley (group C).

RESULTS

Gliding resistance increased significantly after repair and squaring off the oblique pulley (group A, 0.22 +/- 0.08 N; group B, 1.29 +/- 0.68 N; and group C, 2.01 +/- 0.84 N).

CONCLUSIONS

Previous studies suggest that the trimming of an annular pulley in the finger would not result in any significant mechanical disadvantage if other parts of the pulley system were intact. However, the authors' results suggest that in the case of the thumb oblique pulley, gliding resistance is increased after trimming and tendon repair, and thus the oblique pulley should be left intact if possible.

Microarray analysis of mechanical shear effects on flexor tendon cells

BACKGROUND

Adhesion formation after flexor tendon repair remains a clinical problem. Early postoperative motion after tendon repair has been demonstrated to reduce adhesion formation while increasing tendon strength. The authors hypothesized that during mobilization, tendon cells experience mechanical shear forces that alter their biology in a fashion that reduces scar formation but also activates key genes involved in tendon healing.

METHODS

To test this hypothesis, primary intrinsic tenocyte cultures were established from flexor tendons of 20 Sprague-Dawley rats and sheared at 50 rpm (0.41 Pa) using a cone viscometer for 6 and 12 hours. Total RNA was harvested and compared with time-matched unsheared controls using cDNA microarrays and Northern blot analysis.

RESULTS

Microarray analysis demonstrated that mechanical shear stress induced an overall "antifibrotic" expression pattern with decreased transcription of collagen type I and collagen type III. Shear stress down-regulated profibrotic molecules in the platelet-derived growth factor, insulin-like growth factor, and fibroblast growth factor signaling pathways. In addition, shear stress induced an overall decrease in transforming growth factor (TGF)-beta signaling pathway molecules with down-regulation of TGF-beta2, TGF-beta3, TGF-RI, and TGF-RII expression. Moreover, sheared tendon cells increased expression of matrix metalloproteinases and decreased expression of tissue inhibitors of metalloproteinase, an expression pattern consistent with an antifibrotic increase in extracellular matrix degradation. However, the authors also found up-regulation of genes implicated in tendon healing, specifically, vascular endothelial growth factor-A and several bone morphogenetic proteins. Interestingly, the known mechanoresponsive gene, TGF-beta1, also implicated in tendon healing, was differentially up-regulated by shear stress. Northern blot validation of our results for TGF-beta1, TGF-beta2, TGF-beta3, and collagen type I demonstrated direct correlation with the authors' microarray data.

CONCLUSIONS

The authors demonstrate an overall antifibrotic expression pattern in response to shear stress in tendon cells that may provide insight into the mechanisms by which early mobilization decreases adhesion formation without impaired tendon healing.

Optimum locations of the locking loop and knot in tendon sutures based on the locking Kessler method

BACKGROUND

We investigated the factors that influence tensile strength and resistance to gap formation at the repair site of tendon suture (stiffness) by comparing (1) the location of the locking loops and (2) the location of the knot.

METHODS

Transected bovine tendons of the medial gastrocnemius (9-11 x 14-16 mm diameter) were sutured with a modified locking Kessler method with a USP (United States Pharmacopeial convention) 2 polyester multifilament suture (0.500-0.599 mm) and loaded to failure using an Instron 5565 tensiometer. The locking loops were located on either the upper surface facing the operator or on side portions of the tendon. The knot was positioned either close to or far from the tendon stump.

RESULTS

The locations of the locking loops did not influence the tensile strength; however, the stiffness of the side loop suture (5.70 +/- 0.09 N/mm) was significantly higher than that of the upper surface loop suture (5.17 +/- 0.10 N/mm). Regarding the knot location, the tensile strength with the knot far from the tendon stump (195.1 +/- 4.8 N) was significantly higher than that with the knot close to the tendon stump (169.0 +/- 3.6 N), although the stiffness was unchanged by differences in knot location.

CONCLUSIONS

These data suggested that a greater tensile strength with less of a gap is obtained by (1) forming locking loops in the side portion of the tendon, and (2) forming knots far from the tendon stump.

Recent progress in flexor tendon healing. The modulation of tendon healing with rehabilitation variables

Until recently, attempts to optimize the postoperative regimen following intrasynovial flexor tendon repair had been essentially empirical, in that both the time and graduation of the exercise regimen have lacked clear conceptual guidelines. The magnitude of load applied in previous studies had not been clearly controlled, and similarly, the effects of increased repair site excursion and gap formation had not been evaluated in clinically relevant models. Recent experimental in vivo data on the application of force and excursion as independent variables by the authors and other investigators have helped to clarify the respective roles of these two variables. The goal of surgical treatment of intrasynovial flexor tendon lacerations is the achievement of a primary tendon repair of tensile strength sufficient to allow early controlled motion after surgery. The implementation of an appropriate postoperative rehabilitation protocol will, based on the experimental data discussed in this article, decrease the formation of intrasynovial adhesions, facilitate the restoration of the gliding surface, and stimulate the accrual of strength at the repair site.

Repair of zone II flexor digitorum profundus lacerations using varying suture sizes: a comparative biomechanical study

PURPOSE

To compare the maximum tensile load, change in work of flexion, and gapping at the repair site after zone II flexor digitorum profundus tendon repairs using 2-0, 3-0, and 4-0 braided polyester 4-strand locked cruciate repair technique in fresh-frozen cadaveric hands with standard 6-0 suture epitenon repairs, to determine which suture size is the best for a core repair.

METHODS

A randomized study was designed using 41 tendons from 15 fresh-frozen cadaveric hands. We included only the flexor digitorum profundus tendons from the index, middle, and ring fingers to minimize variation between digits. Core suture size was randomized for each finger. A sharp laceration through the flexor digitorum profundus in zone II was made and a 4-strand locked cruciate braided polyester core stitch was performed along with a locked epitenon stitch. Cyclic loading was performed for 1,000 cycles. For each tendon the mean work of flexion (before/after zone II repair) and maximum tensile load were measured using a custom-designed tensiometer, as was gapping before maximum tensile loading.

RESULTS

Mean gaps after 1,000 load-unload cycles to 3.9 N of pulp pinch did not approach the clinically significant limit of 3 mm in each group. By using a regression model, we found that the prerepair and postrepair comparisons for mean work of flexion to a 3.9-N pulp pinch showed the greatest change in work of flexion for 2-0 braided polyester. Statistical significance was found between 2-0 braided polyester and 3-0 or 4-0 braided polyester; however, the work of flexion between the 3-0 and 4-0 polyester was not clinically significant. The highest maximum tensile load was obtained with suture size 2-0 braided polyester. The maximal tensile load statistically showed 2-0 braided polyester to be stronger than 4-0 braided polyester but we found no statistically significant difference between 3-0 and 2-0 braided polyester or between 3-0 and 4-0 braided polyester.

CONCLUSIONS

In this cadaveric study we found that increasing locking cruciate suture caliber from 4-0 to 2-0 increased maximum tensile strength but also caused increased work of flexion. Gapping was not affected by suture caliber. There was no significant difference in strength or mean change in work of flexion between 3-0 or 4-0 braided polyester sutures.