Gene expression of Postn and FGF7 in canine chordae tendineae and their effects on flexor tenocyte biology

Chordae tendineae, referred to as heart tendinous cords, act as tendons connecting the papillary muscles to the valves in the heart. Their role is analogous to tendons in the musculoskeletal system. Despite being exposed to millions of cyclic tensile stretches over a human's lifetime, chordae tendineae rarely suffer from overuse injuries. On the other hand, musculoskeletal tendinopathy is very common and remains challenging in clinical treatment. The objective of this study was to investigate the mechanism behind the remarkable durability and resistance to overuse injuries of chordae tendineae, as well as to explore their effects on flexor tenocyte biology. The messenger RNA expression profiles of chordae tendineae were analyzed using RNA sequencing and verified by quantitative reverse transcription polymerase chain reaction  and immunohistochemistry. Interestingly, we found that periostin (Postn) and fibroblast growth factor 7 (FGF7) were expressed at significantly higher levels in chordae tendineae, compared to flexor tendons. We further treated flexor tenocytes in vitro with periostin and FGF7 to examine their effects on the proliferation, migration, apoptosis, and tendon-related gene expression of flexor tenocytes. The results displayed enhanced cell proliferation ability at an early stage and an antiapoptotic effect on tenocytes, while treated with periostin and/or FGF7 proteins. Furthermore, there was a trend of promoted tenocyte migration capability. These findings indicated that Postn and FGF7 may represent novel cytokines to target flexor tendon healing. Clinical significance: The preliminary discovery leads to a novel idea for treating tendinopathy in the musculoskeletal system using specific molecules identified from chordae tendineae.

Complications and Clinical Outcomes Following Zone I Flexor Tendon Repair Using All-Inside Suture Fixation

PURPOSE

The purpose of this study was to evaluate complications and outcomes of an all-inside repair technique for flexor digitorum profundus (FDP) avulsions.

METHODS

A retrospective review of a single institution database identified all FDP avulsions that were repaired using an all-inside technique by a single surgeon. In this method, 2 Keith needles are drilled from the volar to dorsal aspect, exiting proximal to the nail matrix and within the extensor tendon. Nonabsorbable sutures were placed in the flexor tendon and passed through the bone tunnels, tying dorsally over the distal phalanx. The demographics characteristics, injury characteristics, the surgical procedure, postoperative complications, and outcomes were reviewed.

RESULTS

Seventeen patients were included in the study. The average age was 40 years (range, 21-68 years), and 2 patients were women. Seventeen fingers were included: 14 ring fingers, 1 index finger, and 2 little fingers. Six patients had an associated distal phalanx fracture and one had an associated distal interphalangeal joint dislocation. The average time between injury and surgery was 9 days (range, 2-18 days). Four patients had complications: 3 with erythema related to infection, which appeared to be a reaction to the suture prompting removal, and 1 with a subungual mass related to the suture at removal. One patient had persistent pain. Postoperative range of motion, assessed using the Strickland criteria, was excellent or good in 5 (33%) of 15 patients, but this was predominantly due to motion at the proximal joints as overall DIP motion was limited. Patients had a mean distal interphalangeal joint range of motion of 24° (range, 0° to 55°).

CONCLUSIONS

In our series, repair of FDP avulsions via all-inside suture fixation is associated with limited distal interphalangeal joint motion and an incidence of infection (24%) at final follow-up.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic V.

What is new in flexor tendon pulleys and the gaps between them in triphalangeal fingers of the hand?

The flexor tendon pulleys in the fingers of the hand are fibrous structures of variable size, shape, and thickness that cover the synovial sheath of these tendons. Despite their clinical relevance, their arrangement and configuration in each of the triphalangeal fingers have been little studied and with small sample sizes. 192 triphalangeal fingers belonging to 48 fresh body donors' hands were dissected. Multivariate analysis was carried out. Twenty-five cases (52%) were left hands, and 26 of the 48 hands belonged to female donors (54.2%). The results were analyzed by fingers for each of the 5 annular pulleys, the 3 cruciform pulleys and the gaps between them. In addition, the most and least frequent configurations of the pulleys in each of the fingers were studied, observing that the classic pattern with all the pulleys appeared only in 3 fingers (1.56%), while the most frequent pattern was A1-A2-C1-A3-A4, which was seen in 35 fingers (18.22%). CONCLUSIONS: The flexor pulleys in the triphalangeal fingers of the hand have shown enormous variability in arrangement and shape, and also rarely appear all in the same finger. This peculiar anatomical arrangement can help the different professionals who perform their clinical work in this region.

Anatomical design and production of a novel three-dimensional co-culture system replicating the human flexor digitorum profundus enthesis

The enthesis, the specialized junction between tendon and bone, is a common site of injury. Although notoriously difficult to repair, advances in interfacial tissue engineering techniques are being developed for restorative function. Most notably are 3D in vitro co-culture models, built to recreate the complex heterogeneity of the native enthesis. While cell and matrix properties are often considered, there has been little attention given to native enthesis anatomical morphometrics and replicating these to enhance clinical relevance. This study focuses on the flexor digitorum profundus (FDP) tendon enthesis and, by combining anatomical morphometrics with computer-aided design, demonstrates the design and construction of an accurate and scalable model of the FDP enthesis. Bespoke 3D-printed mould inserts were fabricated based on the size, shape and insertion angle of the FDP enthesis. Then, silicone culture moulds were created, enabling the production of bespoke anatomical culture zones for an in vitro FDP enthesis model. The validity of the model has been confirmed using brushite cement scaffolds seeded with osteoblasts (bone) and fibrin hydrogel scaffolds seeded with fibroblasts (tendon) in individual studies with cells from either human or rat origin. This novel approach allows a bespoke anatomical design for enthesis repair and should be applied to future studies in this area.

Current clinical opinion on surgical approaches and rehabilitation of hand flexor tendon injury-a questionnaire study

The management of flexor tendon injury has seen many iterations over the years, but more substantial innovations in practice have been sadly lacking. The aim of this study was to investigate the current practice of flexor tendon injury management, and variation in practice from the previous reports, most troublesome complications, and whether there was a clinical interest in potential innovative tendon repair technologies. An online survey was distributed via the British Society for Surgery of the Hand (BSSH) and a total of 132 responses were collected anonymously. Results showed that although most surgeons followed the current medical recommendation based on the literature, a significant number of surgeons still employed more conventional treatments in clinic, such as general anesthesia, ineffective tendon retrieval techniques, and passive rehabilitation. Complications including adhesion formation and re-rupture remained persistent. The interest in new approaches such as use of minimally invasive instruments, biodegradable materials and additive manufactured devices was not strong, however the surgeons were potentially open to more effective and economic solutions.

Bizarre Parosteal Osteochondromatous Proliferation (Nora's Lesion) Of the Second Proximal Phalanx Encasing the Flexor Tendon of the Foot: A Case Report

Introduction

Bizarre Parosteal Osteochondromatous Proliferation (BPOP) is a rare benign lesion commonly referred to as Nora's lesion. It typically affects adults in their 20s-30s. Due to its aggressive local invasion, it can be confused with some malignant tumors, including chondrosarcoma. Nora's lesion can be diagnosed radiographically, and its diagnosis is confirmed with an excisional biopsy.

Case Report

A 40-year-old Bahraini male complained of swelling over the metatarsal head of the second digit, increasing in size over a year. He also complained of a reduced range of motion of the second toe and a pins-and-needles sensation affecting the entire toe. Plain X-ray, computed tomography, and magnetic resonance imaging were done, showing findings suggestive of bizarre parosteal osteochondromatous. The lesion was encasing the flexor tendon of the second digit. He was treated with surgical excision, and histopathology confirmed the diagnosis of BPOP.

Conclusion

We report on a rare presentation of BPOP in the second proximal phalanx of a male in his 40 s. The patient underwent a wide local excision, and the diagnosis was confirmed with histopathology.

Techniques for Retrieval of Lacerated Flexor Tendons: A Scoping Review

Introduction: Flexor tendon laceration is often followed by retraction of the proximal stump. The goals of this review were to describe the myriad of proximal stump retrieval surgical techniques and where available to provide the clinical evidence associated with each. Methods: A Medline and Web of Science search was performed to identify any publication whose primary purpose was to describe a tendon retrieval technique. The techniques were assigned to 8 groups. Clinical outcomes, where reported, and advantages and disadvantages of the technique as reported by the authors of the articles were analyzed. Results: Eight-hundred and forty-one publications complied with the search terms, and 33 articles were included in the current analysis. Only 2 of these articles were randomized controlled trials, and they were of low quality. Conclusion: There is no high-quality evidence to allow quantitative comparison of tendon retrieval techniques. An incremental approach can be recommended based on the qualitative review. After failed atraumatic attempts to retrieve the tendon by milking, retrieval should be done through proximal incision at the A1 pulley level, preferably without pulling the tendon out of the wound. When available, using an endoscope to retrieve the tendon appears to be a promising alternative.

Partially Lacerated Digital Flexor Tendons: A Cadaveric Study Determining the Intact Cross-sectional Area and Biomechanical Analysis

BACKGROUND

The extent of injury in partially lacerated tendons has conventionally been expressed as a percentage of the total tendon, to justify surgical repair. We propose a more objective method to estimate the cross-sectional area of the remnant intact tendon and to determine if the remaining tendon fibers can withstand the tensile forces of early active mobilization against resistance.

METHODS

The study was done on 20 cadaveric specimens, which were randomly assigned to receive a laceration of 25%, 50%, or 75% of the measured transverse tendon diameter. The circumference of the remaining intact portion of the partially lacerated tendon was measured and converted using a formula to determine the derived cross-sectional area (D-CSA). These D-CSA values were then validated by comparing them to digitally measured cross-sectional areas using a computer software program (computer-measured cross-sectional area, C-CSA). In addition, the ultimate tensile strength (UTS) of these partially lacerated tendons was analyzed to determine if a threshold exists beyond which surgical repair of a partially lacerated tendon is indicated.

RESULTS

We found that the D-CSAs matched moderately with C-CSAs, with 0.622 of Pearson correlation coefficient. The UTSs of tendons with CSAs above 8 mm in circumference were consistently above 150 N.

CONCLUSION

Measurement of the circumference of the partially lacerated tendon to obtain the D-CSA could be an accurate and practical method to benchmark residual tendon strength in the management of partially lacerated tendons.

Traction Tenolysis for Flexor Tendon Adhesions: Outcomes in 97 Patients

PURPOSE

Traction tenolysis is an alternative, less invasive way of performing flexor tendon tenolysis by winding affected tendons around a surgical instrument. This study assessed outcomes and complications in a cohort of patients who underwent traction tenolysis to determine its effectiveness.

METHODS

We retrospectively reviewed 97 patients who underwent traction tenolysis performed by 4 fellowship-trained hand surgeons from 2010 to 2019. We collected data on preoperative and postoperative ranges of motion, the number and type of prior ipsilateral hand surgeries, and the duration of therapy and follow-up. Cases of traditional open tenosynovectomy tenolysis were excluded.

RESULTS

Approximately two-thirds of the patients achieved more than 75% of the normal total active motion, and 80% achieved at least 50% of the normal total active motion. The mean total active flexion increased significantly by 42° and passive flexion by 25°. The differences in active and passive flexion significantly decreased from 28° before the surgery to 9° after the surgery. The active and passive flexion of the distal interphalangeal and proximal interphalangeal joints improved similarly, at approximately 20° and 10°, respectively. The average duration of follow-up was 11 ± 8 weeks. The complication rate was 5%: 1 case of intraoperative flexor digitorum superficialis tendon rupture, 1 case of postoperative infection, and 3 reoperations because of failure to progress.

CONCLUSIONS

Traction tenolysis is an alternative to traditional open tenolysis surgery in selected patients.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Carpal tunnel syndrome caused by tophi in the superficial flexor tendon: a case report

Carpal tunnel syndrome (CTS) is the most common disease among peripheral nerve entrapment diseases. CTS is often caused by the hyperplasia of the transverse carpal ligament and edema of tissue in the carpal tunnel, resulting in compression of the median nerve. Specific manifestations of CTS include numbness, loss of skin sensation in the palm and three and a half fingers on the radial side, and decreased muscle strength; however, CTS caused by wrist tophi is very rare. To our knowledge, CTS with median nerve compression caused by tophi in the superficial flexor tendon of the index finger of the wrist has not been reported before. Here, we will report a case of CTS caused by tophi in the wrist in a 37-year-old patient with no history of gout. CTS caused by tophi is uncommon, but if the patient has high uric acid, CTS may be due to tophi.

Evaluation of Outcome Measures of Zone V Flexor Tendon Injury: A Systematic Review

Background  Flexor tendon injury zone V is a multicomponent soft tissue injury involving tendons, nerves, and vessels. Outcome assessment of repair thus requires evaluation of the hand as a whole rather than solely evaluating tendon function. The purpose of this Preferred Reporting Items for Systematic Reviews and Meta-Analyses -compliant systematic review was to identify and assess the components of outcome measures used in flexor zone V. Methods  A total of 3,761 studies were retrieved from four databases (PubMed, ProQuest, Cochrane Central, and Google Scholar). These studies were then screened for inclusion using a validated screening form. Fifteen articles fulfilling the eligibility criteria were included in the review. Subsequently, the included studies were assessed for methodological quality using the Joanna Brigg Institute tool. Results  Out of the 15 studies, 11 were case series, 3 were cross-sectional studies, and 1 was a randomized controlled trial. Out of 15 included studies, 13 were of low risk, whereas 2 studies suggested moderate risk when assessed for methodological quality using the Joanna Brigg Institute tool. Eight outcome measures were identified, out of which the most frequently used were Total Active Motion by the American Society for Surgery of Hand (TAM-ASSH) and Noaman's criteria. Our study found that Noaman's criteria assessed sensory-motor function and finger deformity in addition to the range of motion (ROM), which was found to be assessed by all the other outcome measures. Conclusion  We concluded that although Buck-Gramcko criteria is well suited for the ROM evaluation, Noaman's criteria, a recently developed outcome measure used exclusively for combined injuries in zone V, took into consideration the implications of nerve injury along with tendon function. Although being specifically designed for combined injuries of tendons, nerves, and vessels in zone V, there is a lack of usage of Noaman's in the literature. There still exists a lack of a consistent and appropriate choice of outcome measure.

Correction of a Hyperflexed Hallux in a Saker Falcon (Falco cherrug) by Hemisectioning the Deep Digital Flexor Tendon

A 3-year-old male saker falcon (Falco cherrug) was presented with a history of hyperflexion of the first digit of the left pelvic limb with what appeared to be a hypercontracted distal end of the deep digital flexor tendon (m. flexor hallucis longus). Conservative treatment, bandaging, and splinting techniques failed to resolve the hypercontraction of the deep digital flexor tendon and improve digit function. Intraoperatively, the deep digital flexor tendon was found to have formed adhesions with the tendon sheath as well as the bone and soft tissue structures underneath it, impeding its ability to move freely within the tendon sheath. The adhesions were surgically resolved, and the tendon was lengthened by hemisectioning the deep digital flexor tendon at its distal end. Postsurgically, the digit was maintained in an extended position by bandaging. Mild physiotherapy was provided at 5-day intervals to retain function and prevent adhesions. Digit extensibility and function were restored to nearly normal levels after 4 weeks.

Comparative sensitivity and accuracy of 24 vs. 18 MHz ultrasound probes for the diagnosis of flexor tendon repair integrity

Purpose

To determine whether a 24 MHz transducer significantly improves sensitivity, specificity and accuracy in evaluating flexor tendon repair integrity compared with an 18 MHz transducer.

Methods

One hundred and twelve cadaveric digits were randomised to an intact repair or simulated 'failed' repair, and to a two- or eight-strand repair of a flexor digitorum profundus laceration. A blinded sonologist evaluated specimens in static mode using 18 and 24 MHz transducers. Gaps were remeasured after scanning, and final gap width recorded. McNemar's exact test calculated differences between sensitivity, specificity and accuracy, and chi-squared test to compare sensitivity, specificity and accuracy between number of strands (2 vs. 8) and repair gap (≥4 mm).

Results

The 24 MHz transducer had higher sensitivity (81 vs. 59%), lower specificity (67 vs. 70%) and higher overall accuracy (74 vs. 64%), than the 18 MHz transducer. The difference for sensitivity was significant (P = 0.011), but not differences for specificity and overall accuracy (P > 0.05). Pearson's correlation (r = 0.61) demonstrated a moderate-to-strong positive correlation between measured and true gap sizes. Increased number of suture strands (2 vs. 8) did not impair sensitivity, specificity nor accuracy.

Discussion

Ultrasound may tend to overestimate gap width, and a slight risk that some intact repairs, or those with small, clinically insignificant gaps may undergo surgical exploration that may not be indicated.

Conclusions

A 24 MHz transducer is a more sensitive and accurate transducer for assessing flexor tendon repair integrity and measuring small gaps.

Influence of the direction of suture strands on the tensile strength after flexor tendon repairs

We assessed the influence of different directions of suture strands using the double Tsuge repair on the resistance to gap formation and mode of failure. In total, 25 porcine flexor digitorum profundus tendons were split into two groups. One group was repaired using a conventional double Tsuge suture created by two bands of looped suture placed longitudinally parallel (parallel method), and the other group was repaired using a new technique comprising two bands of looped suture placed in a crossed fashion in the anterior and posterior half of the tendon (cruciate method). The repaired tendons were subjected to linear, non-cyclic load-to-failure tensile testing. The cruciate method had a significantly higher mean load at a 2-mm gap tensile load (29.7 N [SD, 8.3]) than the parallel method (21.6 N [SD, 4.9]) and failed significantly more often due to suture pull-out. The direction of a core suture and its location within the tendon affect both gap resistance and the mode of failure of repair when using the double Tsuge suture technique, with a cruciate configuration achieving a greater gap resistance than a parallel one.

Biomechanical Evaluation of a Tubular Braided Construct for Primary Deep Flexor Tendon Surgery

PURPOSE

Immediate postoperative mobilization has been shown to avoid adhesion formation and improve range of motion after flexor tendon repair. A tubular braided construct was designed to allow for these rehabilitation protocols.

METHODS

In this ex vivo study, 92 ovine flexor tendons were divided randomly into 2 equal groups. After creating a transection, the tendons of the first group were repaired using a tubular braided construct. This construct, consisting of a tubular braid of polypropylene and polyethylene terephthalate fibers, exerts a grasping effect on the tendon ends. The control group received a multistrand modified Kessler repair with a looped polydioxanone suture (PDS) 4-0 suture and a Silfverskiöld epitendinous repair using an Ethilon 6-0 suture. After the repair, a static and an incremental cyclic tensile test was performed until failure.

RESULTS

During the static test, the tubular braid resulted in a significantly higher load at 3 mm gap formation (86.3 N ± 6.0 vs 50.1 N ± 11.6), a higher ultimate load at failure (98.3 N ± 12.7 vs 63 N ± 11.1), higher stress at ultimate load (11.8 MPa ± 1.2 vs 8.1 MPa ± 3.1), and higher stiffness (7.1 N/mm ± 2.9 vs 8.7 N/mm ± 2.2). For the cyclic tests, survival analyses for 1-, 2- and 3-mm gap formation and failure demonstrated significant differences in favor of the tubular braided construct.

CONCLUSION

The tubular braided construct withstands the required loads for immediate rehabilitation not only in static tests, but also during cyclic tests. This is in contrast with the control group, where sufficient strength is reached during static tests, but failures occur below the required loads during cyclic testing.

CLINICAL RELEVANCE

The tubular braided construct provides a larger safety margin for immediate intensive rehabilitation protocols.

Flexor Tendon Repair in Zone II Augmented With an Externalized Detensioning Suture: Protected Flexor Tendon Repair

Flexor tendon repair in zone II benefits from early finger motion to prevent stiffness. This article presents a technique that serves to augment a zone II flexor tendon repair with an externalized detensioning suture that can be used following any commonly employed repair method. This simple technique enables early active motion and is suited for patients who are less likely to be compliant after surgery or when the soft-tissue injury to the finger and hand is substantial. Although this technique substantially strengthens the repair, a possible drawback is that the tendon excursion distal to the repair is limited until the externalized suture is removed, which may lead to less motion of the distal interphalangeal than what may have occurred without the detensioning suture.

PAI-1 mediates TGF-β1-induced myofibroblast activation in tenocytes via mTOR signaling

Transforming growth factor-beta (TGF-β1) induces plasminogen activator inhibitor 1 (PAI-1) to effect fibrotic pathologies in several organs including tendon. Recent data implicated PAI-1 with inhibition of phosphatase and tensin homolog (PTEN) suggesting that PAI-1-induced adhesions involves phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (mTOR) signaling. Ergo, we investigated effects of TGF-β1, PAI-1, and mTOR signaling crosstalk on myofibroblast activation, senescence, and proliferation in primary flexor tenocytes from wild-type (WT) and PAI-1 knockout (KO) mice. PAI-1 deletion blunted TGF-β1-induced myofibroblast activation in murine flexor tenocytes and increased the gene expression of Mmp-2 to confer protective effects against fibrosis. While TGF-β1 significantly reduced phosphorylation of PTEN in WT cells, PAI-1 deletion rescued the activation of PTEN. Despite that, there were no differences in TGF-β1-induced activation of mTOR signaling (AKT, 4EBP1, and P70S6K) in WT or KO tenocytes. Phenotypic changes in distinct populations of WT or KO tenocytes exhibiting high or low mTOR activity were then examined. TGF-β1 increased alpha-smooth muscle actin abundance in WT cells exhibiting high mTOR activity, but this increase was blunted in KO cells exhibiting high 4EBP1 activity but not in cells exhibiting high S6 activity. DNA damage (γH2AX) was increased with TGF-β1 treatment in WT tenocytes but was blunted in KO cells exhibiting high mTOR activity. Increased mTOR activity enhanced proliferation (Ki67) in both WT and KO tenocytes. These findings point to a complex nexus of TGF-β1, PAI-1, and mTOR signaling in regulating proliferation, myofibroblast differentiation, and senescence in tenocytes, which could define therapeutic targets for chronic tendon adhesions and other fibrotic pathologies.

Preclinical tendon and ligament models: Beyond the 3Rs (replacement, reduction, and refinement) to 5W1H (why, who, what, where, when, how)

Several tendon and ligament animal models were presented at the 2022 Orthopaedic Research Society Tendon Section Conference held at the University of Pennsylvania, May 5 to 7, 2022. A key objective of the breakout sessions at this meeting was to develop guidelines for the field, including for preclinical tendon and ligament animal models. This review summarizes the perspectives of experts for eight surgical small and large animal models of rotator cuff tear, flexor tendon transection, anterior cruciate ligament tear, and Achilles tendon injury using the framework: "Why, Who, What, Where, When, and How" (5W1H). A notable conclusion is that the perfect tendon model does not exist; there is no single gold standard animal model that represents the totality of tendon and ligament disease. Each model has advantages and disadvantages and should be carefully considered in light of the specific research question. There are also circumstances when an animal model is not the best approach. The wide variety of tendon and ligament pathologies necessitates choices between small and large animal models, different anatomic sites, and a range of factors associated with each model during the planning phase. Attendees agreed on some guiding principles including: providing clear justification for the model selected, providing animal model details at publication, encouraging sharing of protocols and expertise, improving training of research personnel, and considering greater collaboration with veterinarians. A clear path for translating from animal models to clinical practice was also considered as a critical next step for accelerating progress in the tendon and ligament field.

Flexor Tendon Pulley Injuries: A Systematic Review of the Literature and Current Treatment Options

Closed injuries of the finger flexor pulley system are rare among the general population, and most of them occur during rock climbing. During the last few decades, scientific interest on this topic has increased. We conducted a systematic review of the literature according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. The research was limited from January 2000 to March 2022. PubMed and Scopus databases were investigated for full-text articles published in English, French, and Italian using the following MeSH terms: ([pulley rupture] OR [finger pulley lesion]) AND ([injur*] OR [ruptur*] OR [damage] OR [trauma*]). Initial screening results identified 461 studies, among which 172 were included after including additional records identified through other sources and excluding repeated studies. Finally, four clinical studies were included in the analysis. The methodological quality of the articles was evaluated through the methodological index for nonrandomized studies (MINORS) score. Our search identified four studies that enrolled a total of 189 patients, of whom 164 were male and 25 were female. We finally examined 154 patients with a total of 208 pulleys damaged. Except for the thumb, all fingers were involved. Depending on the type of flexor pulley injury, graded with Schöffl classification, 69 patients underwent a surgical procedure, whereas 85 patients were treated conservatively. Closed finger pulleys injury occurred in rock climbers and non - rock climbers. All patients had excellent results on the Buck-Gramcko score regardless of the return to sports activity. Considering the overall outcomes of the reviewed articles, functional results were satisfactory in both conservative and surgical treatment. Moreover, in grade 3 and 4, surgical results were positive regardless of the specific technique used for finger pulley reconstruction. Only minor complications were reported. Closed flexor tendon pulley injuries require a careful clinical and imaging examination to confirm the diagnosis. In most cases, positive clinical results can be achieved with either conservative or surgical therapy.

MRI-Based Evaluation of the Flexor Digitorum Superficialis Anatomy: Investigating the Prevalence and Morphometry of the "Chiasma Antebrachii"

Recent dissection studies resulted in the introduction of the term "chiasma antebrachii", which represents an intersection of the flexor digitorum superficialis (FDS) tendons for digits 2 and 3 in the distal third of the forearm. This retrospective investigation aimed to provide an MRI-based morphologic analysis of the chiasma antebrachii. In 89 patients (41 women, 39.3 ± 21.3 years), MRI examinations of the forearm (2010-2021) were reviewed by two radiologists, who evaluated all studies for the presence and length of the chiasma as well as its distance from the distal radioulnar and elbow joint. The chiasma antebrachii was identified in the distal third of the forearm in 88 patients (98.9%), while one intersection was located more proximally in the middle part. The chiasma had a median length of 28 mm (interquartile range: 24-35 mm). Its distances to the distal radioulnar and elbow joint were 16 mm (8-25 mm) and 215 mm (187-227 mm), respectively. T1-weighted post-contrast sequences were found to be superior to T2- or proton-density-weighted sequences in 71 cases (79.8%). To conclude, the chiasma antebrachii is part of the standard FDS anatomy. Knowledge of its morphology is important, e.g., in targeted injections of therapeutics or reconstructive surgery.

Pathological anatomy, classification and treatment of the atypical Wassel Type VI thumb duplication

We studied the pathological anatomical structures of atypical Wassel Type VI thumb duplication to provide a theoretical basis for surgical treatment. Forty-seven patients with atypical Wassel Type VI thumb duplication were treated. We found that some of cases had an ulnar thumb without an extensor tendon, or without a flexor tendon, or without both. All the ulnar metacarpal bones were abnormal to variable degrees. On-top-plasty is currently the best procedure for the treatment of this type of anomaly. Flexor tendon reconstruction is an important factor in functional reconstruction of the thumb, and keeping the pulley and sheath intact is a key step in flexor tendon reconstruction. Placing the on-top-plasty level at the distal end of the metacarpal or at the proximal phalanx depends on the presence of the flexor tendon. According to the condition of the flexor tendon, the atypical Wassel Type IV duplication can be divided into two types: the absent type and the intact type.Level of evidence: VI.

Clinical Outcomes After Aggressive Active Early Motion and Modified Kleinert Regimens: Comparison of 2 Consecutive Cohorts

BACKGROUND

Modern multistrand repairs can withstand forces present in active flexion exercises, and this may improve the outcomes of flexor tendon repairs. We developed a simple home-based exercise regimen with free wrist and intrinsic minus splint aimed at facilitating the gliding of the flexor tendons and compared the outcomes with the modified Kleinert regimen used previously in the same institution.

METHODS

We searched the hospital database to identify flexor tendon repair performed before and after the new regimen was implemented and invited all patients to participate. The primary outcome was total active range of motion, and secondary outcomes were Disabilities of Arm, Shoulder, and Hand; grip strength; globally perceived function; and the quality of life.

RESULTS

The active range of motion was comparable between the groups (mean difference = 14; 95% confidence interval [CI], -8 to 36; P = .22). Disabilities of Arm, Shoulder, and Hand; grip strength; global perceived function; and health-related quality of life were also comparable between the groups. There was 1 (5.3%) rupture in the modified Kleinert group and 4 (15.4%) in the early active motion group (relative risk = 0.3; 95% CI, 0.04-2.5; P = .3).

CONCLUSIONS

Increasing active gliding with a free wrist and intrinsic minus splint did not improve the clinical outcomes after flexor tendon injury at a mean of 38-month follow-up.

Two Cases of Delayed Flexor Tendon Rupture Decades After Reconstruction

Two patients are presented with late-term ruptures of their flexor tendon grafts 10 and 40 years, respectively, after reconstruction. Both occurred from low-energy mechanisms. Their ruptures were intratendinous and not at the proximal or distal insertions. Electron microscopy demonstrated degeneration and increased matrix deposition. Immunohistology showed viable tenocytes, but no clear vascular organization to the disrupted grafts. Even after clinically successful flexor tendon autograft, tendons may still be at risk of degeneration and rupture a decade or more after reconstruction.

The Effect of Flexor Digitorum Profundus Repair Position Relative to Camper Chiasm on Tendon Biomechanics

PURPOSE

The purpose of this study was to investigate the impact of repairing a zone II flexor digitorum profundus (FDP) laceration anatomically versus extra-anatomically on tendon loads and work of flexion (WOF).

METHODS

Twenty digits from 5 cadaveric specimens were tested using an in vitro active finger motion simulator under 2 FDP tendon repair conditions: anatomic and extra-anatomic. Tensile loads in FDP and flexor digitorum superficialis (FDS), WOF, and total active finger range of motion (ROM) were measured using in-line load cells and electromagnetic tracking, respectively.

RESULTS

The anatomic repairs had no effect on tendon loads or WOF for either FDP or FDS. The extra-anatomic repairs increased FDP loads by 32% and decreased FDS loads by 9% compared with those in the intact condition. This pattern was similar for WOF following extra-anatomic repairs, which increased FDP WOF by 31% and decreased FDS WOF by 18%. Comparing the 2 repairs, FDP loads and WOF were 25% and 22% greater, respectively, with extra-anatomic repairs compared with anatomic repairs, with no significant change in FDS. Total active ROM was not affected by either repair.

CONCLUSIONS

In this in vitro cadaveric model, extra-anatomic repairs of FDP increased tendon loads and WOF compared with anatomic repairs.

CLINICAL RELEVANCE

On the basis of this study, reconstitution of the anatomic relationship of FDP and FDS at the Camper chiasm during the repair of zone II flexor tendon lacerations is recommended.

Technique and biomechanical properties of the side-to-side Z-lengthening in spasticity-correcting surgery- a study on porcine tendons

Spasticity-correcting surgery in patients with injuries to upper motor neurons include various techniques, including tenotomies and lengthening of tendons of spastic muscles. Early mobilization including active loading of a lengthened tendon is essential to prevent adhesion formation, which necessitates a lengthening technique that resists the forces produced by the involved muscles. This study on animal tendons reports the biomechanical properties in regards to elongation and load to failure in porcine tendons lengthened by either a 3 or 5 cm overlap and tested in a simple force rig. The lengthening technique used in these tendons is described in step-by-step detail. The mean elongation of 20 lengthened tendons at 100 N was 10 mm for tendons with a 3 cm overlap and 6 mm for tendons with a 5 cm overlap. The mean peak load at failure of the construct was 138 N for lenghened tendons with a 3 cm overlap and 201 N for tendons with a 5 cm overlap. The results of this study indicate that a tendon lengthened by the described technique with a mere overlap of three cm will withstand the estimated forces elicited by muscles in the forearm immediately after surgery.

A 3-Dimensional Suture Technique for Flexor Tendon Repair: A Biomechanical Study

PURPOSE

Flexor tendon injury continues to pose a number of challenges for hand surgeons. Improving mechanical properties of repairs should allow for earlier and unprotected rehabilitation. A 3-dimensional (3D) 4-strand suture technique has been proposed to combine high tensile strength and low gliding resistance without causing suture pullout due to tendon delamination. Our hypothesis is that the 3D technique can result in better mechanical properties than the Adelaide technique.

METHODS

Four groups of 10 porcine flexor tendons were sutured using the 3D or Adelaide technique with a 3-0 polypropylene or ultrahigh molecular weight polyethylene (UHMWPE) suture. The axial traction test to failure was performed on each tendon to measure 2-mm gap force and ultimate tensile strength.

RESULTS

The mean 2-mm gap force was 49 N for group A (3D + polypropylene), 145 N for group B (3D + UHMWPE), 47 N for group C (Adelaide + polypropylene), and 80 N for group D (Adelaide + UHMWPE). Failure mode was caused by suture breakage for group A (10/10) and mainly by suture pullout for the other groups (8/10 up to 10/10). With the UHMWPE suture, the mean ultimate tensile strength was 145 N for the 3D technique and 80 N for the Adelaide technique.

CONCLUSIONS

Porcine flexor tendons repaired using the 3D technique and UHMWPE suture exceeded a 2-mm gap force and tensile strength of 140 N. The ultimate tensile strength was superior to that of the Adelaide technique, regardless of the suture material.

CLINICAL RELEVANCE

This in vitro study on porcine flexor tendon suture highlights that the mechanical properties of 3D repair are better than those of 3D repair using the Adelaide technique when a UHMWPE suture is used.

Is conservative management of partial zone II flexor tendon laceration possible? A systematic literature review and meta-analysis

Background: There is still no consensus on managing zone II level partial flexor tendon lacerations, and the management of zone II partial flexor tendon injuries is controversial. No reliable large cohort studies or metaanalysis papers on partial flexor tendon laceration management are available in PubMed or Embase.Methods: We searched PubMed, Embase, Cochrane Library, Insight, Scopus, and Web of Science databases for primary research articles investigating outcomes of patients with partial flexor tendon injuries. The initial search was limited to human studies that were published from 1970-2021 and indexed as randomized controlled or clinical trials or observational, cross-sectional, or cohort studies. We used statistical package R version 4.1.2 for this meta-analysis.Results: The Standardised mean difference (SMD) of the common effects model was 2.020 (95% CI; 1.583-2.457; P < 0.0001), indicating that the results of conservative treatment without surgical intervention are similar to surgical intervention or better in some articles. The SMD of the random effect model was 7.093 (95% CI; 1.090-13.096; P < 0.0206), indicating the same result. Higgins' I2 value was 97.6%, indicating serious heterogeneity.Conclusions: In this first meta-analysis on flexor zone II conservative treatment, five papers with publication bias were analyzed. It is meaningful to verify the result of conservative treatment statistically. Even though this is a heterogeneous paper, conservative treatment seems to have a lot of benefits for the patient, including offering a fairly solid longterm prognosis with very few complications.

The Application of Hyaluronic Acid/Alginate Sheet to Flexor Pollicis Longus Tendon Repair to Prevent Adhesion Formation: A Second Look

Soft tissue traumas with tendon lacerations are challenging injuries to manage. Repair of these tendon injuries can be complicated by adhesions postoperatively, limiting patient function and satisfaction. Biologic agents have been developed to optimize tendon gliding after repair and can be used as adjuncts. When used in conjunction with a postoperative rehabilitation protocol, they can help restore function and range of motion (ROM). It is rare that the orthopedic surgeon can visualize a healed tendon repair as the results are often followed clinically. We present the case of a patient who underwent flexor tendon repair with the addition of hyaluronic acid (HA) and alginate tendon wrap. This same patient sustained a distal radius fracture one year later, allowing for a second look at the flexor tendon repair site during the operative fixation of his fracture.

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

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

Risk factors for reoperation after flexor tendon repair: a registry study

The aim of this study was to identify risk factors for reoperations after Zones 1 and 2 flexor tendon repairs. A multiple logistic regression model was used to identify risk factors from data collected via the Swedish national health care registry for hand surgery (HAKIR). The studied potential risk factors were age and gender, socio-economics and surgical techniques. Included were 1372 patients with injuries to 1585 fingers and follow-up of at least 12 months (median 37 IQR 27-56). Tendon ruptures occurred in 80 fingers and tenolysis was required in 76 fingers. Variables that affected the risk of rupture were age >25 years (p < 0.001), flexor pollicis longus tendon injuries (p < 0.001) and being male (p = 0.004). Injury to both finger flexors had an effect on both rupture (p = 0.005) and tenolysis (p < 0.001). Understanding the risk factors may provide important guidance both to surgeons and therapists when treating patients with flexor tendon injuries.Level of evidence: III.

The incidence and shape of the digital pulleys: a study of 192 fingers in 48 cadaveric hands

We dissected 192 fingers in 48 fresh cadaveric hands (23 right and 25 left hands from 26 female and 22 male donors) and analysed the incidence, location, length and structure of the five annular and three cruciform pulleys. No statistically significant differences were found between left and right or between male and female hands. The A1, A2 and A4 pulleys were present in all fingers, while the incidence of other pulleys varied. We found 32 different patterns of pulley combinations. The structure of the pulleys also varied. Most important was the variation of A1, which consisted of one to four separate rings. In 18% there was no gap between the A1 and A2 pulleys. A greater understanding of the anatomical variation of the pulley system is beneficial for hand surgeons performing open or percutaneous trigger finger releases and for radiologists examining the area sonographically.

Formation of multiple ganglion cysts along the flexor tendon after open A1 pulley release for trigger finger: A case report

RATIONALE

When surgical treatment is indicated for primary trigger finger, open A1 pulley release has traditionally been recommended with generally good results. However, ganglion cysts of the flexor tendon sheath as a complication after an open A1 pulley release were rarely reported. Therefore, the purpose of this study is to report a case of multiple ganglion cysts arising from the flexor tendon sheath in a patient undergoing an open A1 pulley release for trigger finger disorder with a review of the relevant literature.

PATIENT CONCERNS AND DIAGNOSIS

A 65-year-old right-handed farmer was referred to our hospital for swelling in the left long finger (LLF). One year before the visit, the patient was diagnosed with trigger finger in the LLF at other hospital and an open A1 pulley release was performed, but the swelling of the finger persisted. The patient had no history of trauma or evidence of systemic disease such as rheumatoid or other inflammatory arthritis. The patient was diagnosed with multiple ganglion cysts of flexor tendon sheath after investigation.

INTERVENTION AND OUTCOMES

We successfully excised cystic masses and debrided the partially ruptured flexor digitorum superficialis (FDS) tendon and sutured it using 5/0 prolene. At 12-month follow-up, the patient was completely asymptomatic with excellent range of motion in the distal interphalangeal (DIP) joint (0°-60°) of his LLF, showing no recurrence of ganglion cyst.

LESSONS

Trigger finger is a common condition that clinicians encounter frequently. However, this familiarity may lead to inattentive treatment. Nevertheless, through this case, clinicians should devote careful attention when performing open A1 pulley release to prevent partial rupture of the flexor tendon in the A1 pulley. If ganglion cysts occur, we believe that surgical excision can yield good results.

Morphological Changes in Flexor Tendon Adhesion Following Early Exercise After Tendon Repair

Adhesion is a common complication following surgical repair of flexor tendons, resulting in the restriction of tendon gliding. We investigated the effect of early exercise on adhesion formation. To create an adhesion model, the proximal region of the second phalanx of the third toe in 4-month-old White Leghorn chickens was cut. The gliding side of the flexor digitorum profundus was hemiresected and the bony floor was crushed to enhance adhesion formation. The resected area was fixed in an extended position for 1, 2, or 3 weeks. Following 1, 2, or 3 weeks of active exercise, the chickens were sacrificed and morphological changes in the adhesions were assessed. In the 1- and 2-week fixed groups, 1, 2, or 3 weeks of active exercise resulted in mesotenon-like adhesion that was elastic and had no effect on tendon gliding. However, in the 3-week fixed group, a mature adhesion remained with limited change and tendon gliding was inhibited even after 3 weeks of active exercise. Thus, we concluded that adhesions become more elastic with early exercise within 2 weeks after tendon repair, but that adhesions following tendon repair tend not to show any further elastic changes when exercise is started 3 weeks after the repair.

Outcomes After Flexor Tendon Injuries in the Pediatric Population: A 10-Year Retrospective Review

Background: Pediatric outcomes after flexor tendon repairs are variable, and evidence in the literature remains scarce. Methods: Repair of pediatric flexor tendon injuries was reviewed over a 10-year period (2005-2015). Data collection consisted of patient demographics, injury characteristics, anesthetic choice, repair technique, rehabilitation protocol, American Society for Surgery of the Hand Total Active Motion (TAM) scores, and complications. Results: There were 109 patients included in our study, with a total of 162 digits injured and 235 flexor tendon injuries. The mean age was 12 ± 4.6 years. The small finger (48 of 162; 30%) and the flexor digitorum profundus tendon (126 of 235) were the most commonly injured. The mechanism of injury was mainly from a knife (46 of 109; 42.2%) in zone II (82 of 159; 52%). Injuries were mostly repaired under general anesthetic (61 of 104; 56%). The Kessler technique was the predominant repair mechanism (111 of 225 repairs; 49%). Most patients (103 of 109; 95%) had excellent or good TAM scores with 5 postoperative ruptures reported. The most common complication was stiffness (17 of 121 complications; 14%), with most patients having no complications ( 74 of 109 patients; 68%). Patients were commonly immobilized (mean 8.4 ± 10.3 weeks) with a splint (93 of 109; 85%). There were 85 patients who followed a postoperative rehabilitation protocol for 12 ± 18 weeks. Patient demographics, time of repair, injury characteristics, anesthetic choice, and rehabilitation protocol were not significantly correlated with TAM scores or complication rates. Conclusions: Pediatric tendon injuries have good outcomes with no predictive factors identified. Surgical repairs performed under local anesthetic have similar outcomes without increased rates of complications, but remain underused in the pediatric population.

Zone II Flexor Pollicis Longus Repair: Thumb Flexion and Complications

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

Comparison of 4 Different 4-Strand Core Suturing Techniques for Flexor Tendon Laceration: An Ex Vivo Biomechanical Study

BACKGROUND

Forces applied to the repaired flexor tendon should not exceed its yield force during early postoperative rehabilitation to prevent gapping and rupture. We aimed to biomechanically compare the tensile strengths and the 2-mm gapping of 4 different 4-strand core suturing techniques for flexor tendon repair.

METHODS

Fifty-six goat deep digital flexor tendons were repaired with the 4-strand double-modified Kessler, the 4-strand augmented Becker, the 4-strand Savage, and the 4-strand modified Tang techniques. All tendons were repaired with 4-0 polyester for core suture and 5-0 polyester for continuous epitendinous running suture. The specimens were subjected to static linear tensile testing by applying a single linear load-to-failure pull. After the linear load testing, the yield load, the ultimate strength of the repaired tendons, and the force exerted to yield a 2-mm gap were measured.

RESULTS

All peripheral sutures ruptured near the yield point. All core suture techniques were similar regarding the yield force. The augmented Becker 4-strand technique had the greatest ultimate strength (98.7 [82-125.3] N). The modified double Kessler technique was the weakest in resisting a 2-mm gap formation. The 4-strand modified Tang repair had the shortest (11.3 [7-15] minutes), while the 4-strand augmented Becker had the longest operative time (29 [23-33] minutes).

CONCLUSIONS

All 4 techniques demonstrated similar yield force, with differences in operative time, ultimate strength, and resistance to gapping. Future clinical studies can further elucidate their appropriateness for early active motion protocols.

Preventing postoperative adhesions after hand tendon repair using acellular dermal matrix

AIMS

Postoperative tendon adhesions contribute to functional disability and reconstructive failure. In this study, we present the long-term outcomes of a prospective study in which acellular dermal matrix (ADM) was used to prevent postoperative adhesion after tendon injury.

METHODS

The study was conducted between March 2014 and February 2017. Patients, aged 19-65 years, with an acute single flexor tendon injury in zones 1 or 2, distal to the palmar digital crease were candidates for the study. Patients were allocated to either an ADM treatment group or a control group without ADM treatment.

RESULTS

A total of 37 patients were enrolled in the study: 21 patients in the ADM group and 16 patients in the control group. At six months after surgery, the range of motion in the proximal interphalangeal joint was 81.0±5.1 degrees in the ADM group and 75.8±6.9 degrees in the control group. The range of motion in the distal interphalangeal joint was 79.9±7.1 in the ADM group and 71.2±5.7 degrees in the control group, with significant difference (p=0.03 and p<0.05, respectively). In addition, the total active motion was higher in the ADM group than in the control group. The patients' scores on the Patient Satisfaction Questionnaire were also significantly different, with higher satisfaction scores in the ADM group (p=0.02). The minimal follow-up period was six months.

CONCLUSION

The use of ADM after tendon repair has the potential to significantly improve the outcome of tendon surgery in terms of range of motion.

DECLARATION OF INTEREST

None of the authors has any financial interest in the products, devices, or drugs mentioned in this article.

Collagenase Use and a Trap for the Unwary in Patients With Upper Limb Spasticity

Collagenase has revolutionized the treatment of Dupuytren's disease. It acts by lysing collagen in Dupuytren's cords. It can also act on collagen in tendons, leading to tendon rupture. In this letter, we highlight caution where bowstringed flexor tendons were masquerading as Dupuytren's cords in a patient with upper limb spasticity. The initial plan was to inject the cords with collagenase; however, we proceeded with an open approach. If we had proceeded with our initial plan to inject the palpable cords with collagenase, tendon rupture would have been the likely outcome. We advise that administrators of collagenase proceed with caution in patients with upper limb neurological disorders, bearing in mind that bow-stringed flexor tendons can mimic Dupuytren's cords.

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

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

[Clinical application of Wide-awake technique in flexor tendon tenolysis]

Objective

To discuss the method and effectiveness of Wide-awake technique in flexor tendon tenolysis.

Methods

The clinical data of 16 patients (22 fingers) with flexor tendon adhesion treated by Wide-awake technique for flexor tendon tenolysis between May 2019 and December 2019 were retrospectively analyzed. The patients were all male, aged from 18 to 55 years old, with an average of 35 years old. Among them, 4 cases (7 fingers) after replantation of severed fingers, 4 cases (7 fingers) after flexor tendon rupture repair, and 8 cases (8 fingers) after open reduction and internal fixation of proximal fractures. The time from the original operation to this operation was 6-18 months, with an average of 8 months. The visual analogue scale (VAS) score was used to evaluate the patient's pain during local anesthesia (when the first needle penetrated the skin), intraoperative, and 24 hours postoperatively; and the recovery of finger movement was evaluated by total finger joint active range of motion (TAM) evaluation system and Strickland (1980) standard after operation.

Results

Intraoperative hemostasis and anesthesia were satisfactory, and the patient could fully cooperate with the surgeon in active finger movements. There were different degrees of pain during local anesthesia (VAS score was 2-4), no pain during operation (VAS score was 0), and different degrees of pain after operation (VAS score was 1-8, 9 patients needed analgesics). All incisions healed by first intention after operation. All 16 cases were followed up 9-15 months with an average of 12 months. Finger function was significantly improved, no tendon rupture occurred. At last follow-up, the patients after proximal fracture open reduction and internal fixation were rated as excellent in 4 fingers and good in 4 fingers according to the TAM standard, and both were excellent according to the Strickland (1980) standard; and the patients after replantation of severed fingers and flexor tendon rupture repair were rated as excellent in 4 fingers and good in 10 fingers according to TAM standard, and as excellent in 6 fingers and good in 8 fingers according to Strickland (1980) standard.

Conclusion

Wide-awake technique applied in flexor tendon tenolysis can accurately judge the tendon adhesion and release degree through the patient's active activity, achieve the purpose of complete release, and the effectiveness is satisfactory; the effectiveness of tendon adhesion release surgery after fracture internal fixation is better than that of patients after tendon rupture suture and replantation.

Comparative Sensitivity and Specificity of Static and Dynamic High-Resolution Ultrasound in Diagnosis of Small Gaps in Repaired Flexor Tendons: A Cadaveric Study

PURPOSE

To compare the sensitivity and specificity of high-resolution static and dynamic ultrasound (US) for diagnosing intact repairs and small, clinically relevant gaps (≥4 mm) in repaired flexor digitorum profundus tendons within zone 2 and, secondarily, to evaluate the effect of suture artifact from 3 commonly used suture types.

METHODS

Eighty-eight fresh-frozen cadaveric digits (thumbs excluded) were randomized to either an intact repair (0-mm gap) or repairs using a locked 4-strand suture repair with either 4-0 Prolene, Ethibond, or FiberWire and gaps of 2, 4, or 6 mm and no suture in which 2-, 4-, or 6-mm gaps were created without a suture crossing the repair site. Gap widths were estimated by a blinded musculoskeletal ultrasonographer in static and dynamic modes.

RESULTS

Both static and dynamic modalities tended to overestimate actual gap sizes. For the suture gaps, both modalities had poor sensitivity (29% static; 42% dynamic) for accurately diagnosing a clinically intact repair (<4 mm), but better specificity (83% static; 75% dynamic) for diagnosing a clinically failed repair (≥4-mm gap). Although suture presence decreased the sensitivity of gap width measurement for both modalities, no differences were seen between suture types.

CONCLUSIONS

Static and dynamic US have poor sensitivity for diagnosing clinically intact repairs (gaps < 4 mm) because they typically overestimate gap size. The ability to diagnose failed repairs (gap ≥ 4 mm), based on greater specificity, is much better, but still suboptimal.

CLINICAL RELEVANCE

Based on a receiver operating characteristic analysis cutoff of 5 mm, if a gap of 5 mm or larger is identified with US when evaluating a zone 2 flexor digitorum profundus tendon repair, a failed repair is likely in about 80% of cases. A gap measurement of less than 5 mm may miss a high percentage of repairs that are clinically failed.

A Modified Flexor Tendon Suture Technique Combining Kessler and Loop Lock Flexor Tendon Sutures

OBJECTIVES

In the present study, a novel single knot tenorrhaphy was developed by combining the modified Kessler flexor tendon suture (MK) with the loop lock technique.

METHODS

A total of 48 porcine flexor digitorum profundus tendons were collected and randomly divided into six groups. The tendons were transversely cut and then repaired using six different techniques, the MK method, double knot Kessler-loop lock flexor tendon suture (DK), and single knot Kessler-loop lock flexor tendon suture (SK), each in combination with the epitendinous suture (P), and the same three techniques without P. Furthermore, by performing the load-to-failure tests, the biomechanical properties and the time taken to complete a repair, for each tenorrhaphy, were assessed.

RESULTS

Compared to the MK+P method, DK+P was more improved, thereby enhancing the ultimate tensile strength. The SK+P method, which required fewer knots than DK+P, was easier to perform. Moreover, the SK+P repair increased the force at a 2-mm gap formation, while requiring lesser knots than DK+P.

CONCLUSION

As opposed to the traditional MK+P method, the SK+P method was improved and exhibited better biomechanical properties, which may facilitate early mobilization after the repair.

Complications Following Transosseous Repair of Zone I Flexor Tendon Injuries

PURPOSE

Multiple techniques are described for repair of zone I flexor tendon injuries, many of which are fraught with complications. This study evaluated the clinical complications after a transosseous repair technique.

METHODS

A retrospective review of a single institutional database identified all zone I flexor digitorum profundus (FDP) injuries repaired using a transosseous technique. In this technique, 2 nonabsorbable sutures were passed from volar to dorsal through transosseous tunnels and tied dorsally over the distal phalanx proximal to the germinal matrix. Demographics, injury characteristics, operative details, and complications were reviewed.

RESULTS

Eight patients met the inclusion criteria. Average age was 31 years (range, 15-66 years) and all patients were male. Eight fingers were included: ring (4), small (3), and middle (1). Seven injuries were closed and one was open. Average time between injury and surgery was 13 days (range, 4-34 days). Five patients experienced complications, including osteomyelitis, chronic draining granuloma, and abnormal nail growth. Three patients required an additional operative procedure for management of complications.

CONCLUSIONS

Transosseous repair of zone I flexor digitorum profundus injuries with a buried dorsal suture is associated with a high rate of clinical complications.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic V.

A randomized controlled trial of dorsal web space versus palmar midline injection of steroid in the treatment of trigger digits

One hundred and sixty patients were enrolled in a prospective randomized controlled trial to assess whether a steroid injection through the dorsal web space was less painful than the palmar midline technique in the treatment of trigger digits and whether they were equally effective. There were 116 women and 44 men with a mean age of 60 years. The mean visual analogue score for pain during the injection was 3.6 in the dorsal web space group and 5.4 in the palmar midline group on a scale of 0-10. The overall success of treatment in the dorsal group was 67%, whereas it was 56% in the palmar group. No complications were noted. We concluded from this study that the dorsal web space technique is less painful and at least as effective as the palmar midline technique.Level of evidence: I.

Subcutaneous Transposition of the Flexor Pollicis Longus: Does It Provide Increased Length for Tendon Repair? A Cadaveric Study

Background: Flexor pollicis longus (FPL) tendon lacerations typically occur via sharp mechanisms such as knife injury. When the injury is chronic, it may be difficult to perform a tension free repair, and tendon lengthening may be required. This article proposes a technique that transposes the proximal tendon stump over the thenar eminence subcutaneously, out of the carpal tunnel, in an attempt to gain additional tendon length by eliminating the sharp turn the FPL takes. Methods: A total of 17 cadaveric hands were used. The FPL tendon was identified and affixed to soft tissue in the distal forearm as well as at the thumb metacarpophalangeal (MP) joint with hypodermic needles. The tendon was then transected at the level of the MP joint of the thumb, removed from the carpal tunnel, and transposed on top of the thenar eminence to reach where it had been transected. The length gained by transposing the tendon was recorded by measuring the overlap of the tendon ends at the MP joint. Results: The mean amount lengthened was 7.6 mm with a standard deviation of 2.4 mm, ranging from as little as 5 mm to as high as 13 mm. Conclusions: To our knowledge, transposition of FPL tendon is a novel technique that has not been reported. Based on our cadaveric study, it can be used to bridge gaps between approximately 5 mm and 10 mm. Clinically, this amount of gap could potentially be more easily managed by simply making the repair tighter than usual as opposed to transposing the tendon.

A smartphone application to facilitate adherence to home-based exercise after flexor tendon repair: A randomised controlled trial

OBJECTIVE

Evaluate the effect of a smartphone application on exercise adherence, range of motion and self-efficacy compared to standard rehabilitation after repair of the flexor digitorum profundus tendon.

DESIGN

Prospective multi-centre randomised controlled trial.

SETTING

Four hand surgery departments in Sweden.

SUBJECTS

A total of 101 patients (35 women) (mean age 37.5 ± 12.8) were randomised to control (n = 49) or intervention group (n = 52).

INTERVENTION

A smartphone application to facilitate rehabilitation.

MAIN OUTCOME MEASURES

Adherence assessed with the Sport Injury Rehabilitation Adherence Scale at two and six weeks (primary outcome). Secondary outcomes were self-reported adherence in three domains assessed at two and six weeks, self-efficacy assessed with Athlete Injury Self-Efficacy Questionnaire at baseline, two and six weeks. Range of motion and perceived satisfaction with rehabilitation and information were assessed at 12 weeks.

RESULTS

Twenty-five patients were lost to follow-up. There was no significant between group difference in Sport Injury Rehabilitation Adherence Scale at two or six weeks, mean scores (confidence interval, CI 95%) 12.5 (CI 11.8-13.3), 11.8 (CI 11.0-12.8) for the intervention group, and 13.3 (CI 12.6-14.0), 12.8 (CI 12.0-13.7) for the control group. Self-reported adherence for exercise frequency at six weeks was significantly better for the intervention group, 93.2 (CI 86.9-99.5) compared to the controls 82.9 (CI 76.9-88.8) (P = 0.02). There were no differences in range of motion, self-efficacy or satisfaction.

CONCLUSION

The smartphone application used in this study did not improve adherence, self-efficacy or range of motion compared to standard rehabilitation for flexor tendon injuries. Further research regarding smartphone applications is needed.

LEVEL OF EVIDENCE

I. Randomised controlled trial.

DendroPrime as an adhesion barrier on fracture fixation plates: an experimental study in rabbits

We tested the anti-adhesional effect of a new thiol-ene-based coating in a rabbit model. In 12 New Zealand white rabbits, the periosteum and cortex of the proximal phalanx of the second toe of both hind paws was scratched. Stainless steel plates were fixated with screws. One plate was coated with DendroPrime and the other left bare. The non-operated second toes of both hind paws of an additional four rabbits served as controls. Seven weeks after surgery, the soft tissue adhesion to the plates was evaluated macroscopically, and joint mobility was measured biomechanically. Toe joint mobility was about 20% greater and statistically significant in specimens with coated plates compared with the bare plates. Soft tissue overgrowth and, in some cases, synovitis or adhesions between the plate and the tendon were observed on all bare plates but not on any of the coated plates. We conclude that the thiol-ene-based coating can improve joint mobility by about 20%. This material has a potential to reduce adhesion around plates in fracture surgery.

An Unusual Pattern of Closed Flexor Tendon Avulsion

Closed avulsion of both flexor tendons is an uncommon injury pattern. We discuss a classic rugby jersey injury that resulted in avulsion of both flexor tendons with the flexor digitorum superficialis (FDS) avulsion incorporating a large fracture of the middle phalanx. To our knowledge, this pattern has been described only once in the literature. We propose a modification to the flexor tendon avulsion classification allowing incorporation of this injury pattern to help guide its management.

Infiltration of synovitis into the flexor tendon: a case report

Synovitis is a type of aseptic inflammation that occurs within joints or surrounding tendons. No previous reports have described a hypertrophic synovium eroding the tendon sheath and manifesting as synovitis within the flexor tendon. We herein report a case involving a 10-year-old girl who presented to our hospital with a 1-month history of a swollen mass and progressive inability to completely flex her left index finger. The active flexion angle of the proximal interphalangeal joint was limited to 85°. A longitudinal incision of the flexor digitorum profundus tendon was surgically performed. The synovium inside and outside the flexor digitorum profundus tendon was completely removed. After the surgical excision, normal tendon gliding returned without recurrence by the 1-year follow-up. The active flexion angle of the proximal interphalangeal joint improved to 100°. To the best of our knowledge, this is the first case of synovitis affecting the flexor tendon and leading to limited flexion of a finger. The manifestation of a double ring sign on magnetic resonance imaging is quite characteristic. Early diagnosis and monitoring of the hyperproliferation and invasiveness of the synovial tissue are required. Surgical excision can be a simple and effective tool when necessary.

Zone 2 Flexor Tendon Repair Location and Risk of Catching on the A2 Pulley

PURPOSE

To determine the region of the flexor digitorum profundus (FDP) and flexor digitorum superficialis (FDS) tendons in zone 2 that, when involved by a laceration repair, will reliably catch on the A2 pulley after surgery.

METHODS

Using fresh-frozen cadavers (5 hands, 20 digits), excursions of the FDP and FDS tendons were measured in relation to the A2 pulley. The C1, A3, and C2 pulleys were resected. The digit was maximally flexed by applying traction to the flexor tendon in the forearm. An 8-0 suture tag was placed in the flexor tendons immediately distal to the A2 pulley. The digit was then passively fully extended to measure tendon excursion. Measurements were repeated with 50% venting and 100% release of the A4 pulley. Reference points such as tendon insertions and flexion creases were obtained. This protocol was repeated sequentially for the index, middle, ring, and little fingers.

RESULTS

For all 20 fingers, the suture placed into the FDP just distal to the A2 pulley with the finger fully flexed traveled 1.6 ± 1.9 mm distal to the proximal edge of the A4 pulley with passive extension of the finger. The mean excursion for the FDP was 24.6 ± 3.2 mm, and 16.9 ± 3.1 mm for the FDS. The mean A2 pulley length was 16.2 ± 3.5 mm, and the mean distance between the distal edge of the A2 pulley and the proximal edge of the A4 pulley was 23.0 ± 3.3 mm. Venting the A4 pulley 50% and 100% increased FDP excursion a maximum of 0.9 and 1.9 mm, respectively.

CONCLUSIONS

An FDP repair proximal to the A4 pulley will slide under the A2 pulley with full active digital flexion after surgery. If the distal FDP stump lies underneath the A4 pulley with the digit fully extended, the FDP repair will not likely engage the A2 pulley with full flexion after surgery. The FDP excursion can be reliably predicted as a percentage of the A2 (distal) to the A4 (distal) pulley distance. Most importantly, the distance between the repair site and the A4 pulley approximately equals the length of the A2 pulley that requires release to avoid postoperative triggering.

CLINICAL RELEVANCE

Knowledge of this high-risk region of flexor tendon repair will guide surgeons regarding the potential need for partial release of the A2 pulley.