Effect of suture material and bone quality on the mechanical properties of zone I flexor tendon-bone reattachment with bone anchors

A Meta-Analysis of Biomechanical Studies for Suture Button Pullout Versus Suture Anchor Repair of Flexor Digitorum Profundus Avulsions

BACKGROUND

There is no current consensus on which of the two most common flexor digitorum profundus (FDP) avulsion repair constructs, via suture button pullout (SBP) or suture anchor (SA), is biomechanically superior. Our purpose was to compare these repair methods via systematic review and meta-analysis of available literature.

METHODS

We performed a Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-guided systematic review of PubMed, the Cochrane library, and Embase. We only included studies with direct comparison data for both techniques. We performed a meta-analysis comparing the reported biomechanical results using pooled data for initial repair stiffness (N/mm), gap formation (mm), and ultimate load to failure (N).

RESULTS

Seven studies met inclusion criteria, including a total of 201 cadaveric specimens. Four studies reported initial construct stiffness, with pooled analysis showing superiority for SA repairs (P < .05). Four studies evaluated gap formation, with pooled analysis demonstrating less gapping with SA repair (P < .05). Mean gap formation was 2.4 (±1.4) mm and 3.9 (±2.0) mm for the SA and SBP groups, respectively. All 7 studies assessed load to failure, with pooled analysis revealing no significant difference between groups (P > .05). We lacked statistical power to determine equivalence between techniques for load to failure. Both groups had failure values significantly lower than the native FDP.

CONCLUSIONS

Via meta-analysis, there was increased initial construct stiffness and less gap formation for SA compared to SBP for FDP reinsertion, with no significant differences for ultimate failure load.

[Comparison between different anchors for zone I flexor tendon repair]

INTRODUCTION

Transosseous reinsertion has been used to complement the Bunnell pull-out technique in the repair of zone I deep flexor tendon injuries. The aim of this study is to compare the different devices on the market in terms of complication, functional recovery and ease of use.

MATERIAL AND METHOD

This is a single-center study including all patients who underwent transosseous anchor reinsertion from 2010 to 2021 with a minimum of 6 months of follow-up. Twenty-seven patients were included. The anchors used were of different types: Microfix® Quickanchor plus® and Miniquick anchor® from DePuy Mitek; Juggerknot® Soft Anchor 1.0mm from Zimmer-Biomet; or Kerifix® 4.0 from KeriMedical. We analyzed intraoperative data, complications and functional recovery by quickDASH score.

RESULTS

The average age was 38.6 years (± 16.1), the demographic characteristics were identical in the different groups. There was a significant difference in the number of anchors used intraoperatively before definitive placement (P=0.02), to the disadvantage of the Juggerknot® anchors. There was no significant difference in terms of complications and functional recovery evaluated by the quickDASH.

CONCLUSION

Our study did not find significant differences between the different anchors in terms of complications and functional recovery. Some anchors seem to have a better grip during placement than others.

The Transosseous Internal Four Strand Technique: A New All-Inside Technique for Zone 1 Flexor Tendon Repairs

BACKGROUND

Multiple techniques for the repair of flexor tendon injuries in zone 1 have been proposed over time. While pull-out suture techniques and bone anchor seem to be stronger than internal suture techniques, they are associated with a higher complication rate. We therefore developed an alternative internal suture repair with similar biomechanical stability to those of pull-out sutures and bone anchors.

METHODS

Twenty porcine distal phalanges and deep flexor tendons were randomized to 2 groups of 10 each. The tendons were transsected at the level of the distal interphalangeal joint. In group 1, repairs were performed with a well-established intraosseous suture repair and in group 2 with our new multistrand technique. The repairs were biomechanically tested with linear distraction until failure.

RESULTS

We recorded a significantly higher 2-mm gap force (2GF)-and thus higher stability-of the repairs in group 1 in comparison to group 2. With a 2GF of more than 50 N, our suture technique allows for a modern early active motion rehabilitation protocol. Breakage of the suture construct occurred at random places in the repair in both groups. No pull-outs were noted.

CONCLUSIONS

This study presents a strong transosseous multistrand repair technique for flexor tendon repair in zone 1 that is simple and fast to perform and should have enough strength to withstand early active motion rehabilitation.

Flexor Tendon Reconstruction

Chronic injury to the flexor tendon system of the hand remains a challenging problem for the hand surgeon to treat. Both single- and two-stage techniques remain important in the reconstruction of the flexor tendon deficient digit. Modern advances include the use of allograft composites that aim to reduce the time and donor-site morbidity compared with conventional autograft techniques. Regardless of technique, restoring a gliding tendon-pulley system with a functional arc of motion is the primary goal of flexor tendon reconstruction.

Modified Pull-Out Technique for Zone One Flexor Digitorum Profundus Repair

Pull-out suture fixation is widely used to fix zone one flexor tendon injuries. The original technique of Bunnell generally has good results. However, in some cases, it may result in complications, including nail deformity and infection. The all-inside techniques for fixation of the tendon at this zone cannot totally replace the Pull-out technique. In this article, we propose a modification of the pull-out technique, which can reduce the complications and report the results of our patients' series.

Four Anchor Repair of Jersey Finger

BACKGROUND

Various surgical techniques for treating avulsions of the flexor digitorum profundus tendon at the distal phalanx have been published but no ideal technique has emerged. We introduce a new all-internal 4-anchor flexor tendon repair technique and evaluate outcomes in three clinical cases.

METHODS

In this retrospective case series, we reviewed three patients that sustained an avulsion of the flexor digitorum profundus tendon at the distal phalanx. All patients were surgically treated with the four-anchor repair technique. Two titanium anchors were inserted into the distal phalanx and two all-suture anchors were inserted distal to the first set of anchors. The tendon was then attached to these four anchors using a Krackow stitch pattern and the anchors were sown to each other. Active flexion and extension of the proximal and distal interphalangeal joint were measured at 3-month, 12-month, and 5-year follow-up. Postoperative complications were documented.

RESULTS

All patients achieved excellent clinical outcomes according to assessment criteria. At 3-month follow-up, all patients regained full flexion; two patients had full extension, while one patient was 3 degrees short of full extension. At 12-month follow-up, all patients had full flexion and extension. Five-year follow-up demonstrated the same results with no loss of function, sensation or grip strength. The repairs healed without rupture, and no complications were reported.

CONCLUSION

The 4-anchor flexor tendon repair is a viable surgical technique for zone 1 flexor digitorum profundus tendon repair or reconstruction. Further studies are needed to replicate these promising results and biomechanically validate this technique.Level of Evidence: IV.

Suture tape augmentation improves laxity of MCL repair in the ACL reconstructed knee

PURPOSE

Medial collateral ligament (MCL) injury is very common and surgical repair is sometimes necessary. Especially in the setting of simultaneous anterior cruciate ligament reconstruction (ACLR) as the ACL is the secondary restraint against valgus stress. The goal of this study was to evaluate knee biomechanics after suture repair of the MCL augmented with suture tape, as compared to MCL repair alone, in the setting of concomitant ACL reconstruction (ACLR).

METHODS

Fifteen fresh-frozen human cadaveric knees were tested using a six-degrees-of-freedom robotic system under four loadings: (a) an 89.0 N anterior tibial load, (b) a 5.0 Nm internal and external rotation torque, (c) a 10.0 Nm valgus load, (d) a 7.0 Nm valgus load combined with 5.0 Nm internal rotation torque as a static simulated pivot-shift. The tested conditions were ACLR with the following states: (1) MCL intact, (2) MCL deficient, (3) MCL Repair, and (4) MCL repair augmented with suture tape (MCL Repair + ST). Under the different knee loadings, the tibial displacement, and the force in either the intact MCL, suture repaired MCL or repaired MCL-suture tape complex was measured.

RESULTS

While neither the MCL Repair nor the MCL Repair + ST restored valgus rotation to the MCL intact state, displacement was significantly smaller after MCL Repair + ST (p < 0.05). The knee rotation under external rotation torque in MCL Repair + ST did not differ MCL intact (n.s.), while with MCL Repair the rotation was significantly greater (p < 0.05). MCL Repair + ST did not cause an over-constraint of the knee in any of the tested loading conditions.

CONCLUSION

In a combined ACL-reconstruction-MCL-repair model, MCL Repair augmented with suture tape improved valgus and external rotation laxity when compared to MCL suture repair alone. Suture tape augmentation may provide this additional means of stabilization and can be added at the time of surgical repair of the MCL. Clinically this may result in lower failure rates and less residual laxity after MCL repair, as well as shorter immobilization times and faster return to play.

Transosseous Sutures in Tendon-to-Bone Repairs: the Role of the Epitendinous Suture

BACKGROUND

Numerous transosseous fixation techniques for flexor tendon injuries in Zone 1 of the hand have been described in the literature. While relatively high maximal loads to failure are documented in different biomechanical experiments, several tests revealed a low 2 mm gapping resistance of the tendon-to-bone repairs. We therefore aimed to investigate the effect on gap formation adding a peripheral suture to an established transosseous fixation technique. In addition, we analyzed the influence of different suture materials (braided vs. non-braided) on the stability of the core suture.

METHOD

A total of 30 porcine flexor digitorum profundus tendons were divided into 3 groups (n = 10 each) and repaired using the transverse intraosseous loop technique (TILT). In group 1 and group 2 the repairs were performed using PDS 3-0 or Ethibond 3-0, respectively. In group 3, a peripheral suture was added to the core suture (PDS 3-0) consisting of two figure-of-eight stitches with PDS 5-0. The biomechanical performance of the repaired tendons was analyzed using a standardized protocol.

RESULTS

The suture material and peripheral suture showed no effect on the ultimate failure load in our testing. However, the addition of a peripheral suture led to a statistically significantly higher 2 mm gap force when compared with the repair with a core suture only.

CONCLUSION

In conclusion, addition of a palmar epitendinous suture to the transosseous core suture significantly increases the load to 2 mm gap formation in Zone 1 flexor tendon repairs and thus allows an immediate controlled mobilization.

Flexor Tendon Grafting Using Extrasynovial Tendons Followed by Early Active Mobilization

Purpose

This study evaluated the outcomes of early active mobilization after flexor tendon grafts using extrasynovial tendons with a novel distal fixation technique.

Methods

This study was a retrospective case series. The flexor digitorum profundus (FDP) tendons of 7 digits in 7 patients were reconstructed with extrasynovial tendons, which included the palmaris longs, plantaris, and extensor digitorum longus, in a single- or 2-stage procedure between 2008 and 2017. Of the 7 patients, 6 were male and the average patient age was 48 years. The injuries involved 2 middle, 2 ring, and 3 little fingers. The tendons were sutured into the appropriate FDP tendon proximally using end-weave anastomosis; the distal end of the graft was fixed to the distal stump of the FDP using an interlacing suture or a small bone anchor combined with the pull-through technique. The digits were mobilized with a combination of active extension and passive and active flexion in a protective orthosis during the first 6 weeks after surgery. Average follow-up was 18 months. We measured active and passive digit motion both before tendon grafting and at the final evaluation. Outcomes were graded by the LaSalle formula to assess staged flexor tendon reconstruction.

Results

Average passive range of motion (ROM) of the proximal and distal interphalangeal joints before flexor tendon grafting was 146° (SD, 22°). Mean active ROM of these joints at the final evaluation was 123° (SD, 34°). Using the LaSalle formula, mean recovery of active motion was 83%. We encountered no grafted tendon rupture and no finger required tenolysis.

Conclusions

Our proximal and distal fixation techniques allowed the autologous extrasynovial tendon grafts to withstand the stress encountered during early active mobilization with good postoperative ROM and minimal complications.

Type of study/level of evidence

Therapeutic I.

The evidence-base for the management of flexor tendon injuries of the hand: Review

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There is no consensus on the optimal flexor tendon repair technique at each anatomical flexor zone.

•

There is paucity of high quality evidence.

•

Heterogenous study designs limit inter-study comparisons.

•

Patient reported outcome measures are crucial but there is a perennial need for robust disease-specific tools to be utilised.

Biomechanical Comparison of Flexor Digitorum Profundus Avulsion Repair

Purpose  Multiple repair techniques have been investigated for flexor digitorum profundus (FDP) tendon avulsions. The purpose of this study is to compare the biomechanical characteristics of a new fully threaded titanium suture anchor with previously examined fixation techniques. Methods  Repair of FDP tendon avulsions was performed in 18 fresh-frozen cadavers using one of three implants: Nano Corkscrew FT 1.7 mm suture anchor (Group 1; Arthrex, Inc., Naples, FL; n  = 6), Mitek Micro 1.3 mm suture anchor (Group 2; Mitek Surgical Products, Westwood, MA; n  = 6), or pullout suture button fixation (Group 3; n  = 6). Constructs were preloaded before testing load to failure. For each trial, elongation at 20 N and maximum load, mean load to failure, stiffness, and failure mechanism were recorded. Results  Load to failure occurred in all trials. Mean load to failure was significantly greater for Group 1 (61.6 ± 18.9 N) compared to Group 2 (42.5 ± 4.2 N; p  < 0.05) and Group 3 (41.6 N ± 8.0 N; p  < 0.05). Stiffness was significantly greater in Groups 1 and 2 compared to Group 3 (6.9 ± 2.2 N/mm vs. 6.1 ± 0.8 N/mm vs. 3.1 N/mm ± 0.5 N/mm, respectively, p  < 0.01). Mechanism of failure differed between the groups: Group 1 broke at the anchor in two trials and tore through the tendon in three trials, Group 2's suture universally broke at the anchor, and Group 3's trials mainly failed at the button. Conclusions  The Nano Corkscrew anchor (Group 1) has a significantly higher load to failure when compared with the other techniques. The higher load to failure of the corkscrew anchor provides a secure method for flexor tendon repair in zone I. Clinical Relevance  A fully threaded titanium suture anchor used for FDP tendon avulsion injuries is likely to withstand early active range of motion protocols.

Repair Technique Using a Combination of Suture Anchor and Miniscrew in Flexor Digitorum Profundus Bony Avulsion Fracture with Bone Fragment in Zone 1

Avulsion fracture of the volar base of the distal phalanx is a rare injury. Zone 1 flexor tendon injuries can be treated with either internal or external fixation techniques. Pull-out suture repairs are often used for FDP tendon avulsion injuries. However, the pull out suture technique is associated with a number of well documented complications including nail bed injury and pressure necrosis. Despite the variety of techniques available for the repair of acute distal zone 1 flexor tendon injuries, no one technique has proven to be superior to all others. We address our experience with treatment of FDP avulsion injuries using suture anchor and miniscrew. Our technique supplements the suture anchor technique, which often causes a lack of strength, with an additional miniscrew. We introduce two cases of combined method using both suture anchor and miniscrew for treatment of FDP avulsion injuries.

Accuracy in Screw Selection in a Cadaveric, Small-Bone Fracture Model

PURPOSE

Using a cadaveric model simulating clinical situations experienced during open reduction and internal fixation of proximal phalangeal fractures, the aim of this study was to evaluate the relationship between level of training and the rates of short, long, and ideal screw length selection based on depth gauge use without fluoroscopy assistance.

METHODS

A dorsal approach to the proximal phalanx was performed on the index, middle, and ring fingers of 4 cadaveric specimens, and 3 drill holes were placed in each phalanx. Volunteers at different levels of training then measured the drill holes with a depth gauge and selected appropriate screw sizes. The rates of short, long, and ideal screw selection were compared between groups based on level of training. Ideal screws were defined as a screw that reached the volar cortex but did not protrude more than 1 mm beyond it.

RESULTS

Eighteen participants including 3 hand fellowship-trained attending physicians participated for a total of 648 selected screws. The overall rate of ideal screw selection was lower than expected at 49.2%. There was not a statistically significant relationship between rate of ideal screw selection and higher levels of training. Attending surgeons were less likely to place short screws and screws protruding 2 mm or more beyond the volar cortex CONCLUSIONS: Overall, the rate of ideal screw selection was lower than expected. The most experienced surgeons were less likely to place short and excessively long screws.

CLINICAL RELEVANCE

Based on the low rate of ideal screws, the authors recommend against overreliance on depth gauging alone when placing screws during surgery. The low-rate ideal screw length selection highlights the potential for future research and development of more accurate technologies to be used in screw selection.

Fingertip Winding Suture: Pull-out Suture Technique for Flexor Tendon Repair in Zone I

Injuries to flexor tendons in zone I has always been challenging during repair. Over the time several techniques were developed and modified to achieve the highest repair strength and thus the best functional outcome. These techniques vary from pull-out sutures with internal and external fixation to the use of bone anchors. All techniques were accompanied with advantages and disadvantages as well as postoperative morbidities related to certain techniques. In the present technique we introduce a subperiosteal pull-out suturing technique. It is a simple, strong, and cost-effective method for repair of flexor tendon injuries in zone I or in the context of tendon grafting.

Traumatic avulsion of the flexor digitorum profundus tendon. Jersey finger, a 29 cases report

Traumatic avulsion of flexor digitorum profundus (jersey finger) is an uncommon injury. Our study aimed to describe functional outcomes of jersey fingers after surgical treatment. From January 2004 to 2014, we performed surgery on 32 patients who had jersey finger. Twenty-six of these patients were male and 6 were female with a mean age of 37.2years (range 16-68). Of the 32 cases, 11 were sports injuries, 16 presented on the ring finger and 13 on the little finger. Using the Leddy and Packer and Smith classifications, 16 of the injuries were type I, 4 were type II, 5 were type III, 7 were type IV. The mean time between injury and surgery was 6.8days (range: 0-32). The surgical techniques used were anchor, pull-out, or an association of both these techniques. Prior to the patient discharge, functional outcomes were evaluated. Twenty-nine patients were evaluated in total and three patients were lost. Of the 29, the average time between surgery and discharge was 36.6months ranging from 4.5 to 118months. According to the Buck-Gramcko classification, six patients had an excellent result, six had a good result, seven had a satisfactory result and ten a poor result. The mean Quick DASH score immediately to prior discharge was 5.66 (range: 0-56.82). Twelve complications were reported on nine patients. No infections were reported. Rapid diagnosis and rapid surgical treatment led to restoration of full range motion.

The Pull-out K-wire Anchorage: The "Shepherd's Crook" Technique

Traditional pull-out techniques for tendon and ligament repair are still widely used in hand surgery, despite constant refinements and the development of other methods of fixation. We propose a modification of the classic technique which utilizes a K-wire as an external strut instead of the classic button. This fixation system can be usefully applied in the fixation of extensor and flexor tendons and reinsertions. It is particularly applicable in situations where a transarticular K-wire is to be used anyway, in situations of temporary joint immobilization and in other situations.

Sports-related wrist and hand injuries: a review

Background

Hand and wrist injuries are common during athletics and can have a significant impact especially if initially disregarded. Due to their high level of physical demand, athletes represent a unique subset of the population.

Main body

The following is an overview of hand and wrist injuries commonly seen in athletics. Information regarding evaluation, diagnosis, conservative measures, and surgical treatment are provided.

Conclusion

Knowledge of these entities and special consideration for the athlete can help the team physician effectively treat these players and help them achieve their goals.

Surgical Sutures with Porous Sheaths for the Sustained Release of Growth Factors

Surgical sutures with highly porous sheaths are developed using a swelling and freeze-drying procedure without compromising their mechanical properties. The modified sutures show a high capacity for loading biofactors and are able to release the loaded biofactors in a sustained manner.

[Management of zone 1 flexor digitorum profundus tendon injuries]

Flexor tendons repair in zone 1 is classically considered providing good results with an overall satisfactory finger function. However, the objective functional results after surgical repair of flexor digitorum profundus are sometimes disappointing. The authors describe the different surgical repair techniques available to the operator from so-called "traditional" sutures to newer methods of internal fixation using miniaturized anchor sutures. The management of postoperative procedures, that of failures and old cases are reported.

Comparison of Transverse Intraosseous Loop Technique and Pull Out Suture for Reinsertion of the Flexor Digitorum Profundus tendon. A Retrospective Study

We compared the results of two methods for reinsertion of flexor digitorum profundus tendons retrospectively. In 35 fingers of 29 patients pull-out suture and in 13 fingers of 11 patients transverse intraosseous loop technique was performed with a mean follow-up of 8 and 6 months, respectively. Eleven and nine fingers achieved "excellent" or "good" function according to Strickland and Glogovac at 8 weeks; 20 and ten at the last control in the pull-out and transverse intraosseous loop groups, respectively. The difference at 8 weeks was statistically significant in favour of the transverse intraosseous loop group. Ten patients underwent 12 complications in the pull-out group (four superficial infections; one rerupture, one PIP and one DIP joint contracture, one adhesion, two granulomas, one nail deformity and one carpal tunnel syndrome) and four of them were reoperated (one carpal tunnel release, one teno-arthrolysis and two resections of granuloma). There was no complication and no reoperation in the transverse intraosseous loop group, the difference being statistically significant for the former. In our study the transverse intraosseous loop technique seemed to be a safe alternative with possibly better functional results compared to the pull-out suture.

Distal attachment of flexor tendon allograft: a biomechanical study of different reconstruction techniques in human cadaver hands

We compared the mechanical force of tendon-to-bone repair techniques for flexor tendon reconstruction. Thirty-six flexor digitorum profundus (FDP) tendons were divided into three groups based upon the repair technique: (1) suture/button repair using FDP tendon (Pullout button group), (2) suture bony anchor using FDP tendon (Suture anchor group), and (3) suture/button repair using FDP tendon with its bony attachment preserved (Bony attachment group). The repair failure force and stiffness were measured. The mean load to failure and stiffness in the bony attachment group were significantly higher than that in the pullout button and suture anchor groups. No significant difference was found in failure force and stiffness between the pullout button and suture anchor groups. An intrasynovial flexor tendon graft with its bony attachment has significantly improved tensile properties at the distal repair site when compared with a typical tendon-to-bone attachment with a button or suture anchor. The improvement in the tensile properties at the repair site may facilitate postoperative rehabilitation and reduce the risk of graft rupture.

The outcomes of zone 1 flexor tendon injuries treated using micro bone suture anchors

This article evaluates the outcome of 42 consecutive zone 1 flexor tendon injuries treated by using micro bone anchors during the period 2003-2008. Patients were rehabilitated using the modified Belfast Regime. The range of motion at the distal interphalangeal joint was assessed using Moiemen's classification. A total of 56% of patients achieved excellent or good results for range of motion at the distal interphalangeal joint and 23% had a poor outcome. The mean distal interphalangeal joint and proximal interphalangeal joint range of motion were 48° and 96°, respectively. A total of 94% of patients returned back to work by 12 weeks. One patient sustained a tendon rupture and one developed osteomyelitis. The mean QuickDASH score was 13.5 and 81% of patients were satisfied with their outcomes. This is the largest clinical study on the use of bone anchors for zone 1 tendon injuries. Our study demonstrated a low rate of complications and outcomes that compare favourably with other published techniques.

Mechanical properties of the flexor digitorum profundus tendon attachment

The current study was performed to determine the strength and rigidity of the intact flexor digitorum profundus (FDP) tendon attachment and compare the rigidity at the attachment site to the rigidity within a more proximal part of the tendon. Eight cadaveric index fingers were tested to failure of the FDP tendon. Lines were drawn on each tendon with India ink stain at the position of the attachment to bone and 5 mm and 10 mm proximally. Each test was recorded using a high resolution video camera. A minimum of six images per test were used for analysis of tissue deformation. The centroid of each line was computationally identified to characterize the deformation of the tendon between the lines. Force vs. deformation curves were generated for the 5 mm region representing the tendon attachment and the 5 mm region adjacent to the attachment. Stiffness measurements were generated for each curve, and normalized by the initial length to determine the rigidity. The failure strength ranged from 263 N to 548 N, with rigidity values ranging from 2201 N/(mm/mm) to 8714 N/(mm/mm) and from 3459 N/(mm/mm) to 6414 N/(mm/mm) for the attachment and the tendon proximal to the attachment, respectively. The rigidity did not vary significantly between the attachment and proximal tendon based on a Wilcoxon signed rank test (p = 0.2). The measured strength and rigidity establish biomechanical properties for the FDP tendon attachment to bone.

Comparison of an all-inside suture technique with traditional pull-out suture and suture anchor repair techniques for flexor digitorum profundus attachment to bone

PURPOSE

One goal in repairing zone 1 flexor digitorum profundus (FDP) injuries is to create a tendon-bone construct strong enough to allow early rehabilitation while minimizing morbidity. This study compares an all-inside suture repair technique biomechanically with pull-out suture and double-suture anchor repairs.

METHODS

Repairs were performed on 30 cadaver fingers. In all-inside suture repairs (n = 8), the FDP tendon was attached to bone with two 3-0 Ethibond sutures and tied over the dorsal aspect of distal phalanx. Pull-out suture repairs (n = 8) were performed with 2-0 Prolene suture and tied over a dorsal button. There were 2 suture anchor repair groups: Arthrex Micro Corkscrew anchors preloaded with 2-0 FiberWire suture (n = 7) and Depuy Micro Mitek anchors preloaded with 3-0 Orthocord suture (n = 7). Repair constructs were tested using a servohydraulic materials testing system and loaded until the repair lost 75% of its strength.

RESULTS

There were no statistically significant differences in tensile stiffness, ultimate load, or work to failure between the repairs. Failure mode was suture stretch and gap formation greater than 2 mm at the repair site for all pull-out suture repairs and for 7 of 8 all-inside suture repairs. Two of the Arthrex Micro Corkscrew repairs and 5 of the Depuy Micro Mitek repairs failed by anchor pull-out.

CONCLUSIONS

This cadaveric biomechanical study showed no difference in tensile stiffness, ultimate load, and work to failures between an all-inside suture repair technique for zone 1 FDP repairs and previously described pull-out suture and suture anchor repair techniques. The all-inside suture technique also has the advantages of avoiding an external button and the cost of anchors. Therefore, it should be considered as an alternative to other techniques.

CLINICAL RELEVANCE

This study introduces a new FDP reattachment technique that avoids some of the shortcomings of current techniques.

Modern tendon repair techniques

Digital tendon repair is one of the most common issues in hand surgery and also one of the most vexing. A repair must withstand the forces imparted on it during early motion. Common clinical scenarios that challenge the hand surgeon are flexor tendon injuries in zone II, zone I, and extensor tendons. Repair of tendons that have flat morphology present a particular challenge to achieving a strong repair while maintaining the native tendon shape. This article evaluates modern tendon repair techniques. Early clinical experience using such methods have shown clinical success of improved motion and no known ruptures.

Transosseous fixation in insertional Achilles tendonitis

The surgical approach of severe insertional Achilles tendonitis involves debridement, repair, and reattachment. Previously described techniques for bone-tendon reattachment involved the use of suture anchors in the sparsely trabeculated calcaneus. The following technique tip is a reintroduction of bicortical transosseous fixation previously used in rotator cuff repairs. Bone tunnels are a viable option in the treatment of insertional Achilles tendonitis; however, additional research is necessary to validate its efficacy in this application.

A safety technique for Mitek anchor suture rupture: a useful trick

We propose that the simple method of passing an extra suture through the Mitek anchor eyelet before bony insertion provides a safety net against failure of the preloaded suture and gives extra strength to the core repair.

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.

Improvement of flexor tendon reconstruction with carbodiimide-derivatized hyaluronic acid and gelatin-modified intrasynovial allografts: study of a primary repair failure model

BACKGROUND

Tendon grafts play an important role in flexor tendon reconstruction. This study was an investigation of the effects of surface modification of allograft intrasynovial tendons with carbodiimide-derivatized hyaluronic acid and gelatin in an in vivo canine model. To mimic the actual clinical situation, a novel and clinically relevant model of a failed primary flexor tendon repair was used to evaluate the flexor tendon grafts.

METHODS

Twenty-eight flexor digitorum profundus tendons from the second and fifth digits of fourteen dogs were lacerated and repaired in zone II in a first-surgery phase. The dogs were allowed free active motion postoperatively. In a second phase, six weeks later, the tendons were reconstructed with use of a flexor digitorum profundus allograft. In each dog, one graft was treated with carbodiimide-derivatized hyaluronic acid and gelatin (the CHG group) and the other was treated with saline solution, as a control. The dogs were restricted from free active motion, but daily therapy was performed beginning on postoperative day 5 and continued until six weeks after the operation, when the animals were killed. The outcomes were evaluated on the basis of digit work of flexion, gliding resistance, healing at the distal attachment, graft cell viability, histological findings, and findings on scanning electron microscopy.

RESULTS

In the first phase, all twenty-eight repaired tendons ruptured, with scar and adhesion formation in the repair site. Six weeks after allograft reconstruction, the mean work of flexion was 0.37 and 0.94 N-mm/degree in the CHG group and the saline-solution control group, respectively; these values were significantly different (p < 0.05). The gliding resistance in the CHG group was also significantly less than that in the saline-solution control group (0.18 versus 0.28 N) (p < 0.05), but no difference between groups was observed with regard to the distal tendon-bone pullout strength. Histological analysis showed that tenocytes in the host tendon proliferated and migrated toward the acellular allograft.

CONCLUSIONS

This primary repair failure model was reproducible and reliable, with a uniform failure pattern, and provides an appropriate and clinically relevant animal model with which to study flexor tendon reconstruction. The surface modification of allografts with carbodiimide-derivatized hyaluronic acid and gelatin improved digital function and tendon gliding ability.

Flexor tendon reconstruction

Successful flexor tendon repair has narrowed the indications for flexor tendon grafting. Flexor tendon grafting is the preferred method of treatment for patients with neglected digital flexor tendon lacerations and after the failure of flexor tendon repair. Improvements in tendon repair methods and in aftercare methods have improved the outcomes after flexor tendon grafting. Future improvements in tissue engineering may also improve the results of flexor tendon repair.

The effect of the trabecular microstructure on the pullout strength of suture anchors

This study investigates how the microstructural properties of trabecular bone affect suture anchor performance. Seven fresh-frozen humeri were tested for pullout strength with a 5mm Arthrex Corkscrew in the greater tuberosity, lesser tuberosity, and humeral head. Micro-computed tomography analysis was performed in the three regions of interest directly adjacent to individual pullout experiments. The morphometric properties of bone mineral density (BMD), structural model index (SMI), trabecular thickness (TbTh), trabecular spacing (TbS), trabecular number (TbN), and connectivity density were compared against suture anchor pullout strength. BMD (r=0.64), SMI (r=-0.81), and TbTh (r=0.71) showed linear correlations to the pullout strength of the suture anchor with p-values<0.0001. A predictive model was developed to explain the variances in the individual BMD, SMI, and TbTh correlations. The multi-variant model of pullout strength showed a stronger relationship (r=0.86) compared to the individual experimental results. This study helps confirm BMD is a major influence on the pullout strength of suture anchors, but also illustrates the importance of local microstructure in pullout resistance of suture anchors.