Flexor pulley reconstruction

Comparison of 3T and 7T magnetic resonance imaging for direct visualization of finger flexor pulley rupture: an ex-vivo study

OBJECTIVE

To compare image quality and diagnostic performance of 3T and 7T magnetic resonance imaging (MRI) for direct depiction of finger flexor pulleys A2, A3 and A4 before and after artificial pulley rupture in an ex-vivo model using anatomic preparation as reference.

MATERIALS AND METHODS

30 fingers from 10 human cadavers were examined at 3T and 7T before and after being subjected to iatrogenic pulley rupture. MRI protocols were comparable in duration, both lasting less than 22 min. Two experienced radiologists evaluated the MRIs. Image quality was graded according to a 4-point Likert scale. Anatomic preparation was used as gold standard.

RESULTS

In comparison, 7T versus 3T had a sensitivity and specificity for the detection of A2, A3 and A4 pulley lesions with 100% vs. 95%, respectively 98% vs. 100%. In the assessment of A3 pulley lesions sensitivity of 7T was superior to 3T MRI (100% vs. 83%), whereas specificity was lower (95% vs. 100%). Image quality assessed before and after iatrogenic rupture was comparable with 2.74 for 7T and 2.61 for 3T. Visualization of the A3 finger flexor pulley before rupture creation was significantly better for 7 T (p < 0.001). Interobserver variability showed substantial agreement at 3T (κ = 0.80) and almost perfect agreement at 7T (κ = 0.90).

CONCLUSION

MRI at 3T allows a comparable diagnostic performance to 7T for direct visualization and characterization of finger flexor pulleys before and after rupture, with superiority of 7T MRI in the visualization of the normal A3 pulley.

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.

Closed flexor pulley injuries: A literature review and current practice

Background

Closed flexor pulley injuries are a clinical entity of great interest in hand surgery, and these lesions could be observed mainly in rock-climbing athletes.

Objective

An extensive literature search of PubMed, SCOPUS, Cochrane Library, and Web of Sciences databases on closed finger pulley rupture, related treatments, and outcomes were performed. All relevant information was used in this literature review.

Conclusions

Many athletes are potentially exposed to these uncommon injuries. Therefore, these lesions require careful examination and a high index of suspicion to confirm the diagnosis and identify the degree of soft tissue injury, particularly in patients not involved in sporting activities. The data summarized in this literature review demonstrated that according to Schöffl's classification, conservative treatment should be indicated for low-grade injuries (grade 1 or 2), whereas surgical treatment should be performed in patients with more severe acute injuries (grade 4). Grade 3 flexor pulley injuries lie in a grey area where conservative and surgical treatment may give good clinical and return-to-sport patient results.

Nonoperative Treatment of Finger Flexor Tenosynovitis in Sport Climbers—A Retrospective Descriptive Study Based on a Clinical 10-Year Database

Simple Summary

Finger flexor tenosynovitis is among the most frequent overuse injuries in sport climbers. Targeted therapy is currently based mostly on reports of the anecdotal practical experience of single centers rather than scientific investigations, as there is very little research available on this pathology. The aim of this study was to describe the nonoperative treatment outcomes of finger flexor tenosynovitis treatments in sport climbers by retrospectively asking patients about injury triggers, therapy contents and outcomes. All patients were initially treated conservatively, and only one of the patients needed further therapy in the form of a single injection with hyaluronic acid; none of them underwent further operative treatment. The average symptom duration was 30.5 weeks, and all patients were able to resume climbing, with approximately 75% of them regaining or exceeding their initial climbing level. These good to excellent outcomes and no correlation between particular therapy contents and therapy outcome suggest that finger flexor tenosynovitis in sport climbers has a favorable natural course without requiring invasive therapy. However, further cohort studies and, ultimately, randomized controlled trials are needed to conclusively confirm our promising observations from this study.

Abstract

The aim of this study was to describe the nonoperative treatment outcomes of finger flexor tenosynovitis in sport climbers and to evaluate the association with baseline measures and therapy contents. Sixty-five sport climbers (49 males, mean age 34.1 years) diagnosed with tenosynovitis of the finger flexors were retrospectively asked about injury triggers, therapy contents and outcomes. Pulley thickness was measured by ultrasound. All patients were initially treated conservatively, and only one of the patients needed further therapy (single injection with hyaluronic acid); none of them underwent surgical treatment. The most frequently applied therapy was climbing-related load reduction (91%). The treatment resulted in a statistically significant reduction in pain intensity during climbing (before/after therapy ratio [Visual Analog Scale (VAS)/VAS] = 0.62, 95% CI = 0.55, 0.68). The average duration of the symptoms was 30.5 weeks (range 1–120 weeks). In a multiple linear regression analysis, initial daily life pain intensity and a climbing level higher than 7b according to the French/sport grading scale were the only predictive parameters for the relative change in pain intensity and symptom duration, respectively. All patients were able to resume climbing, with 75% regaining or even exceeding their initial climbing level. The good to excellent outcomes and no correlation between particular therapy contents and therapy outcome may suggest that finger flexor tenosynovitis in sport climbers has a favorable natural course without requiring invasive therapy. However, further cohort studies and, ultimately, randomized controlled trials are needed to conclusively confirm our promising observations.

Comprehending Optimality of Finger Flexor Tendon Pulley System Using Computational Analysis

Existing prosthetic/orthotic designs are rarely based on kinetostatics of a biological finger, especially its tendon-pulley system (TPS). Whether a biological TPS is optimal for use as a reference, say for design purposes, and if so, in what sense, is also relatively unknown. We expect an optimal TPS to yield a high range of flexion while operating with lower tendon tension, bowstringing, and pulley stresses. To gain insight into the TPS designs, we present a parametric study which is then used to determine optimal TPS configurations for the flexor mechanism. A compliant, flexure-based computational model is developed and simulated using the pseudo-rigid body method, with various combinations of pulley/tendon attachment point locations, pulley heights, and widths. Results suggest that three distinct types of TPS configurations corresponding to a single stiff pulley, two stiff pulleys, or one stiff and one flexible-inextensible pulley per phalange can be optimal. For a TPS configuration similar to a biological one, the distal pulleys on the proximal and intermediate phalanges need to be like flexible-inextensible string loops that effectively model the behavior of joint and cruciate pulleys. We reckon that a biological flexor TPS may have evolved to maximize flexion range with minimum possible actuation tension, bowstringing, and pulley stress. Our findings may be useful in not only developing efficient hand devices but also in improving TPS reconstruction surgery procedures.

MRI of Finger Pulleys at 7T-Direct Characterization of Pulley Ruptures in an Ex Vivo Model

The aim of this study was to evaluate 7 Tesla (7T) magnetic resonance imaging (MRI) for direct visualization and specific characterization of the finger flexor pulleys A2, A3, and A4 before and after ex vivo pulley rupture. Thirty fingers of human cadavers were examined before and after pulley disruption with a 26 min clinical 7T pulse sequence protocol. Images were assessed by two experienced radiologists for the presence of pulley rupture. Injury characterization included definition of rupture location, morphology, and complications. Image quality was evaluated according to a 4-point Likert-type scale from “not evaluable” to “excellent”. Macroscopic preparations were used as the reference standard. Direct characterization of intact A2, A3, and A4 pulleys and the corresponding pulley lesions was possible in all cases. The rupture location was distributed equally at the radial, ulnar, and central parts of the pulleys. A dislocation and intercalation of the pulley stump between the flexor tendon and finger phalanges was observed as a complication in 62.5% of cases. The average Likert score for direct visualization of pulleys was 2.67 before rupture and 2.79 after rupture creation, demonstrating adequate image quality for routine application. 7T MRI enables a direct characterization of A2, A3, and A4 pulleys before and after artificial disruption, including the definition of rupture morphology and location as well as the detection of rupture complications. This promises a precise presurgical evaluation of pulley injuries and complicated pulley stump dislocations.

Finger Flexor Pulley Injuries in Rock Climbers

Finger flexor pulley system injuries are the most common overuse injury in rock climbers. These injuries occur rarely outside of rock climbing, owing to the sport's unique biomechanical demands on the finger. As rock climbing continues to grow and earn recognition as a mainstream sport, an understanding of how to diagnose and treat these injuries also has become important. Our purpose is to describe current concepts in anatomy, biomechanics, clinical evaluation, imaging, prevention, and treatment strategies relating to finger flexor pulley system injuries. Our literature search was performed on PubMed with MeSH terms and keywords as subject headings to meet the objectives of this review. The "crimp grip" used in rock climbing is the mechanism for these injuries. The A2, A3, and A4 pulleys are at the highest risk of injury, especially when loaded eccentrically. Physical examination may reveal clinical "bowstringing," defined as the volar displacement of the flexor tendons from the phalanges; however, imaging is required for characterization of the underlying injury. Ultrasound is highly sensitive and specific for diagnosis and is recommended as the initial imaging technique of choice. Magnetic resonance imaging is recommended as an additional imaging study if ultrasound is inconclusive. Properly warming up increases the amount of physiologic bowstringing and is thought to prevent injury from occurring. Pulley injuries may be classified as grade I through IV. Conservative treatment, including immobilization, the H-tape method, and the use of a protective pulley splint, is recommended for grade I to III injuries. Surgical repair is reserved for grade IV injuries that are not amenable to conservative treatment.

Feasibility of Homodigital Flexor Digitorum Superficialis transposition, a new technique for A2-C1 pulleys reconstruction: A kinematic cadaver study

INTRODUCTION

Homodigital flexor digitorum superficialis transposition (HFT) is proposed as a new technique for A2-C1 pulley reconstruction. Flexor digitorum superficialis is transposed on the proximal phalanx and inserted on the pulley rims, crossing over flexor digitorum profundus and acting as a pulley.

MATERIALS AND METHODS

The kinematic feasibility was investigated in a cadaveric bowstring model (after A2 and C1 pulley removal) on 22 fingers (thumb excluded).

RESULTS

HFT was effective in restoring the correct flexion of proximal and distal interphalangeal joints, compared to bowstring model. No adverse events were registered.

CONCLUSION

HFT is a feasible technique. Clinical application is encouraged.

Anatomic Considerations and Reconstruction of the Thumb Flexor Pulley System

Disruption to the flexor pulley system of the thumb is an infrequent but devastating injury that can lead to significant compromise in both strength and function. Acute rupture leads to pain, weakness, reduced range of motion (ROM), and potential bowstringing of the flexor tendons. Conservative treatment with a pulley ring should be considered in all patients. However, failure of conservative treatment and bowstringing of the thumb are indications for operative intervention. Reconstruction of the oblique pulley system can be performed either in situ or using a free palmaris longus graft. Care should be taken to identify the neurovascular bundles to avoid compression during the reconstruction. Conscious sedation protocols augmented by ultrasound-guided sheath blocks allow the patient to actively and strongly contract the flexor pollicis longus tendon intraoperatively to appropriately tension the construct for optimal results. Rehabilitation should be performed in a stepwise manner beginning with early passive ROM, active ROM, and finally strengthening at around 8 weeks postoperative.

Management of Flexor Pulley Injuries with Proximal Interphalangeal Joint Contracture

Flexor pulley ruptures with severe proximal interphalangeal (PIP) joint contracture present a complex challenge for the hand surgeon. Four patients were treated with a delayed presentation of pulley rupture and fixed PIP flexion contracture with a technique of external extension torque application followed by splinting without pulley reconstruction. Using this technique, the PIP joint contractures improved from an average of 66° to an average of 19°, patient satisfaction was high, and the pulley injuries were managed with splinting alone without open pulley reconstruction.

Outcomes of repair of the lacerated A2 pulley with extensor retinaculum during primary flexor tendon repair

We report outcomes of repairing the lacerated A2 pulley with extensor retinaculum graft in ten patients (ten fingers) during primary flexor tendon repair in zone 2. Complete A2 pulley lacerations were found in eight fingers and partial A2 pulley laceration in two. We extended the laceration in the sheath to the middle of the A4 or A1 pulley to allow tendon repair with a four-strand core suture. The A2 pulley was reconstructed with an extensor retinaculum graft. All patients followed the early controlled active mobilization protocol and recovered active range of motion at the interphalangeal joints without major extension deficits. Using the Strickland and Glogovac criteria, there were four excellent, five good and one fair result. One finger was graded excellent, eight good, and one fair according to Tang's criteria. No clinical bowstringing was observed. We conclude that extensive pulley lacerations reconstructed with extensor retinaculum primarily ensure functional recovery after tendon repair.

LEVEL OF EVIDENCE

IV.

Management of complications of flexor tendon injuries

Innovations in operative techniques, biomaterials, and rehabilitation protocols have improved outcomes after treatment of flexor tendon injuries. However, despite these advances, treatment of flexor tendon injuries remains challenging. The purpose of this review is to highlight the complications of flexor tendon injuries and review the management of these complications.

Evidence-based flexor tendon repair

The goal of flexor tendon repair is to achieve normal range of motion of the finger or thumb. The surgical approach depends on the level of injury. Multistrand core suture repairs are recommended for primary flexor tendon repair. It is evident that at least 4 strands are required to an initiate and active range of motion protocol. The epitendinous suture can also increase the strength of the repair. Careful attention to the post-operative therapy regiment is critical to a successful repair.

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

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

The epidemiology of reoperation after flexor pulley reconstruction

PURPOSE

We used a statewide database to determine the incidence of pulley reconstruction and to evaluate the influence of demographics on reoperation. We hypothesized that age, insurance status, and concomitant nerve or tendon procedure would influence the likelihood of reoperation.

METHODS

We used the Statewide Planning and Research Cooperative System ambulatory surgery database from New York, which represents all outpatient surgery in the state. Patients who had flexor pulley reconstruction from 1998 to 2009 were identified using Current Procedural Terminology 4 codes. Subsequent surgery records for these patients were identified through 2010, allowing at least 1 year follow-up. Concomitant nerve procedure and flexor tendon repair/reconstruction were identified. The type and timing of subsequent procedures, including tenolysis and repeat pulley reconstruction, were recorded. Univariate statistics were calculated to compare age, sex, and payer type between patients with and without reoperation. A multivariable, logistic regression model was used to evaluate the association of the demographics with the chances of having reoperation.

RESULTS

There were 623 patients who had flexor pulley reconstruction from 1998 to 2009. The incidence of pulley reconstruction was 0.27 per 100,000 persons, with an annual frequency of 52 procedures. There were 39 (6%) reoperations. There was no difference in age, concomitant nerve or tendon repair, or workers' compensation between patients with and without reoperation. Regression modeling showed a higher likelihood among men of having reoperation.

CONCLUSIONS

Flexor pulley reconstructions are rare. One-quarter of surgeons performed only one flexor pulley reconstruction over a 12-year period. The 6% reoperation rate is similar to our previous findings for flexor tendon repair using similar methodology. Our report provides information that may be useful in counseling patients.