Disruption of the finger flexor pulley system in elite rock climbers

Motion Analysis of the Wrist and Finger Joints in Sport Climbing

Climbing is a fast-growing sport, with one of the most common injuries being a rupture of the finger flexor tendon pulley. The strain on pulleys increases as finger joints flex. However, to our knowledge, no study has conducted a kinematic analysis of climbers' fingers. Thus, this study aimed to examine finger kinematics during typical climbing tasks. Eleven elite climbers performed a sequence of four climbing moves, which were recorded by an optical motion capture system. Participants used crimp, half-crimp, and open-hand grips for three trials each, with the fourth condition involving campusing using any grip except crimp. Mean proximal interphalangeal joint (PIP) flexion during the holding phase was 87° (SD 12°), 70° (14°) and 39° (27°) for the crimp, half-crimp and open-hand grip, respectively. Hence, inter-individual PIP flexion ranges overlap between different gripping conditions. Two different movement patterns emerged in the open-hand grip, possibly influenced by the use of the little finger, leading to varying degrees of flexion in the middle and ring fingers. Avoiding little finger usage in the open-hand grip may reduce load during pulley rupture rehabilitation. The implications of PIP joint angle variability on individual pulley injury risk or prevention warrant further investigation. Motion capture proved effective for understanding finger kinematics during climbing and could guide future studies on pulley injury risk factors.

Comparison of pulley plasty, pulley venting and resection of flexor digitorum superficialis slip after zone II flexor tendon repair: a cadaver study

LEVEL OF EVIDENCE

V.

Three-Loop Technique for Pulley Reconstruction-A Retrospective Cohort Analysis of 23 Patients

Twenty-three patients with a mean age of 52.7 years underwent pulley reconstruction using the Okutsu double- or triple-loop technique after iatrogenic or traumatic rupture of at least two adjacent flexor tendon pulleys in the finger and distal palm; mean age of injury was 4.77 years. The mean follow-up was 4.66 years after reconstruction of mostly A2 pulleys in a single surgeon setting. Outcome measures included ROM, NRS pain, satisfaction, Disabilities of Arm, Shoulder and Hand Questionnaire (DASH) and Krimmer score, Buck-Gramcko score, Jamar grip strength, pinch grip, and vigorimetry compared to the uninjured side. The median patient satisfaction score was 6.6/10. Hand function using the DASH score was 9.5. Grip strength on the Jamar Dynamometer showed only a slight reduction of 13% compared to the uninjured side. The resultant force of the operated fingers on the vigorimeter is almost 60% of that of the contralateral side, and the finger-palm distance of the operated finger was reduced from 2.2 cm to 1.45 cm. Other functional scores, such as Krimmer (82.2) and Buck-Gramcko (10.9), support these good results. The follow-up of patients more than 4.5 years after reconstruction of the A2 and A3 flexor tendon pulley using the double- or triple-loop technique showed acceptable patient satisfaction and good function of the finger in everyday life.

Diagnostic Imaging of A2 Pulley Injuries: A Review of the Literature

Injury to the A2 pulley is caused by high eccentric forces on the flexor-tendon-pulley system. Accurate diagnosis is necessary to identify the most appropriate treatment options. This review summarizes the literature with respect to using ultrasound (US) to diagnose A2 pulley injuries, compares ultrasound to magnetic resonance imaging and computed tomography, and identifies current knowledge gaps. The results suggest that US should be used as the primary imaging modality given high accuracy, relatively low cost, ease of access, and dynamic imaging capabilities. Manual resistance is beneficial to accentuate bowstringing, but further research is needed to determine best positioning for evaluation.

A4 Pulley Reconstruction Using the Superficialis Oblique Flap and the Transverse Double Loop Techniques: A Biomechanical Evaluation Using a Chicken Model

BACKGROUND

The pulley system plays an important role in flexion mechanism. Reconstruction after trauma can be challenging. Numerous techniques have been described with several drawbacks. Herein, we describe the superficialis flap oblique technique for A4 pulley reconstruction using an animal model.

METHODS

Forty-two fresh legs of 21 eight-week-old chickens were used to evaluate the maximum flexion angle (MFA) and force at maximum flexion (FMF) in intact and sectioned A4 pulley equivalents of the third digit after reconstruction with the transverse double loop (TDL) technique and the superficialis oblique flap (SOF) technique. Biomechanical measurements were obtained in an exclusively designed instrument. Descriptive statistics were reported, and mean differences between the reconstructive techniques were analyzed.

RESULTS

Intact and severed A4 pulley equivalent average MFA were 96.50° ± 1.70° and 115.60° ± 1.50°, respectively. Average FMF were 8.16 ± 0.23 psi with the intact pulley and 6.92 ± 0.20 psi with the sectioned pulley (P < 0.001). After reconstruction with TDL and SOF techniques, the legs reached an average MFA at the distal interphalangeal joint of 98.13° ± 1.20° and 96.90° ± 1.30°, respectively. Mean MFA difference was 1.23° (P = 0.03). Force at maximum flexion was 8.12 psi and 8.10 psi for the TDL and SOF techniques (P = 0.6), respectively.

CONCLUSIONS

The authors believe that SOF technique for A4 pulley reconstruction can be used as first option when available, taking into account its theoretical advantages and its proven biomechanical characteristics. Long-term functional results should be assessed to translate these results into the clinical setting.

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.

Viscoelastic properties of the human A2 finger pulley

INTRODUCTION

Biomechanical evaluation of the viscoelastic properties tissue deformation, stiffness, and maximum breaking load of the human A2 pulley. We hypothesized that the A2 pulleys of index, middle, and ring fingers exhibit no difference regarding the aforementioned biomechanical parameters.

METHODS

Forty-one A2 pulleys of 14 upper extremities (8 body donors) were assessed. Cyclic and load-to-failure testing were performed. The biomechanical parameters tissue deformation during cyclic and load-to-failure testing, stiffness, and maximum breaking load were determined.

RESULTS

No significant differences between the fingers could be detected regarding the biomechanical parameters. A significant negative correlation could be detected between stiffness and deformation of the pulley. Significant positive correlations could be identified between stiffness and maximum breaking load and between maximum breaking load and deformation of the pulleys.

CONCLUSIONS

Assessment of the viscoelastic properties of the A2 finger pulley promotes precise diagnosis of pulley lesions and will help to optimize treatment.

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.

The moment arms and leverage of the human finger muscles

The moment arm of a muscle's force represents the muscle's leverage or mechanical advantage in producing a joint moment. It is indicative of the muscle's potential to contribute to actuation of a joint in a particular joint motion direction and defines the role of the muscle, for example, as a joint flexor or abductor. The aims of this study were, firstly, to measure the moment arms of the flexor and extensor muscles of the metacarpophalangeal (MCP), proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints, and the moment arms of the major abductor and adductor muscles of the metacarpophalangeal (MCP) joint of each finger in the hand; secondly, to assess the effect of change in joint angle on these moment arms; and thirdly, to determine if there are differences in a given flexor or extensor's muscle moment arms between the joints it spans on a given finger, and across its tendon slips to multiple fingers. The tendon-excursion method was used to measure instantaneous muscle moment arms in nine fresh-frozen entire forearm cadaver specimens. Joint flexion angle was found to have significant effects on the moment arms of the extensor muscles at the MCP and PIP joints (p < 0.05). In contrast, the digital flexor muscles maintained relatively constant moment arms through the range of joint flexion. The moment arms of the digital flexors and extensors spanning multiple joints in a finger were largest at the MCP joints and smallest at the DIP joints. The findings demonstrate greater torque generating capacity for tasks such as grasping at the proximal interphalangeal joints, and smaller torque capacity for finer movement control at the distal interphalangeal joints. The dataset generated in this study may be useful in the development and validation of computational models used in surgical planning, and rehabilitation.

Flexor Tendon Pulley Injuries in Rock Climbers

Closed pulley ruptures are rare in the general population but occur more frequently in rock climbers due to biomechanical demands on the hand. Injuries present with pain and swelling over the affected pulley, and patients may feel or hear a pop at the time of injury. Sequential pulley ruptures are required for clinical bowstringing of the flexor tendons. Ultrasound confirms diagnosis of pulley rupture and evaluates degree of displacement of the flexor tendons. Isolated pulley ruptures frequently are treated conservatively with early functional rehabilitation. Sequential pulley ruptures require surgical reconstruction. Most climbers are able to return to their previous activity level.

Sonographical parameters of the finger pulley system in healthy adults

INTRODUCTION

To establish normative values of tendon to bone distances (TBDs) to evaluate the A2 and A4 annular pulley integrity, we hypothesized that these values correlate with gender, athletic exercise, occupation, individual's age and body height.

METHODS

Ultrasonography of 200 healthy individuals was performed prospectively. TBDs for the A2 and A4 pulley sections were measured for all fingers. Evaluation was performed in resting position and active forced flexion. Examination parameters included gender, age, body height, occupation, athletic exercise level, and hand dominance. Assessment of resting position and active forced flexion was done.

RESULTS

No clinically relevant differences of TBDs with respect to the aforementioned parameters were observed. But TBDs were significantly greater in active forced flexion than in resting position for all measured pulley sections. Intraobserver reliability was very satisfactory.

CONCLUSIONS

Establishing normative values will help to detect injured pulleys more precisely and examination should be performed both in resting position and active forced flexion.

Caring for Climbers

Caring for climbers can be a challenge and requires familiarity with the distinctive mechanisms of common climbing injuries. Injuries such as climber's finger, climber's elbow, extensor hood syndrome, lateral collateral ligamentous injuries from climbing overload, and posttraumatic osteochondritis dissecans, among others, cannot be diagnosed if the practitioner does not have a specialized knowledge of the sport and the mechanisms of trauma and overuse that can occur. Understanding these injuries will increase the provider's breadth of knowledge and will bridge trust with patients who climb.

Evaluation of finger A3 pulley rupture in the crimp grip position-a magnetic resonance imaging cadaver study

PURPOSE

The correct diagnosis of an A3 pulley rupture is challenging for musculoskeletal radiologists. An A3 pulley rupture should in theory influence the shape of the proximal interphalangeal joint volar plate (VP) and the amount of bowstringing at level of the VP during finger flexion. The purpose of this study was to perform MRI with metric analysis of the VP configuration and VP bowstringing in cadaver fingers in the crimp grip position and to determine cut points for A3 pulley rupture.

MATERIALS AND METHODS

MRI in the crimp grip position was performed in 21 cadaver fingers with artificially created flexor tendon pulley tears (fingers with A3 pulley rupture n = 16, fingers without A3 pulley rupture n = 5). The distances of the translation of the VP relative to the middle phalanx base, the distances between the flexor tendons and the VP body, and the distances between the flexor tendon and bone (TB) were measured.

RESULTS

Statistical analysis showed significantly lower VP translation distances and significantly higher VP tendon distances if the A3 pulley was ruptured. A2 TB and A4 TB distances did not differ significantly in specimens with and without A3 pulley rupture. The optimal cut points for A3 pulley rupture were a VP translation distance <2.8 mm and a VP tendon distance >1.4 mm.

CONCLUSION

Reduction of the VP translation distance and augmentation of the VP tendon distance are suitable indirect signs of A3 pulley rupture.

Flexor digitorum superficialis repair outside the A2 pulley after zone II laceration: gliding and bowstringing

PURPOSE

To evaluate the changes in maximum flexion angle, gliding coefficient, and bowstringing after a combined repair of both flexor tendons with the flexor digitorum superficialis (FDS) rerouted outside the A2 pulley in cadaveric hands.

METHODS

We performed 4 different repairs on cadaveric hands, with each repair tested on 9 unique digits. In total, 12 cadaveric hands and 36 digits were used. The thumb and little finger were removed from each hand and excluded from testing. Group 1 was sham surgery. Group 2 combined flexor digitorum profundus (FDP) and FDS laceration and repair with both slips of the FDS repaired inside the A2 pulley. Group 3 was FDP repair with one slip of the FDS repaired inside A2 and the other slip left unrepaired. Group 4 was FDP repair with both slips of the FDS rerouted and repaired outside the A2 pulley. Maximum flexion angle, gliding coefficient, and bowstringing were measured in simulated active digital motion for each group.

RESULTS

Rerouting and repairing the FDS outside the A2 pulley (group 4) significantly lowered gliding coefficient compared with repairs with both slips inside A2, with values similar to sham surgery. We observed no significant differences in maximum flexion angle among the 4 groups. Increased bowstringing was observed with both slips of the FDS repaired and rerouted outside the A2 pulley.

CONCLUSIONS

In this cadaveric model, repair of both slips of the FDS outside the A2 pulley improved the gliding coefficient relative to repair within the A2 pulley, which suggests decreased resistance to finger flexion. Repair of the FDS outside the A2 pulley led to a slight increase in bowstringing of the FDS tendon.

CLINICAL RELEVANCE

We describe a technique for managing combined laceration of the FDP and FDS tendons that improves gliding function and merits consideration.

Stress examination of flexor tendon pulley rupture in the crimp grip position: a 1.5-Tesla MRI cadaver study

OBJECTIVE

The objectives of this study were the evaluation of flexor tendon pulley rupture of the fingers in the crimp grip position using magnetic resonance imaging (MRI) and the comparison of the results with MRI in the neutral position in a cadaver study.

MATERIALS AND METHODS

MRI in the crimp grip position and in the neutral position was performed in 21 cadaver fingers with artificially created flexor tendon pulley tears (combined pulley rupture, n = 14; single pulley rupture, n = 7). Measurement of the distance between the tendon and bone was performed. Images were evaluated by two readers, first independently and in cases of discrepancy in consensus. Sensitivity and specificity for detecting combined pulley ruptures were calculated.

RESULTS

Tendon bone distances were significantly higher in the crimp grip position than in the neutral position. Sensitivity and specificity for detecting combined pulley rupture were 92.86 % and 100 % respectively in the crimp grip position and 78.57 % and 85.71 % respectively in the neutral position. Kappa values for interobserver reliability were 0.87 in the crimp grip position and 0.59 in the neutral position.

CONCLUSION

MRI examination in the crimp grip position results in higher tendon bone distances by subjecting the pulleys to a higher strain, which facilitates image evaluation with higher interobserver reliability, higher sensitivity, and higher specificity for combined pulley rupture compared with examination in the neutral position.

The role of proximal pulleys in preventing tendon bowstringing: pulley rupture and tendon bowstringing

PURPOSE

The aim of this study was to investigate factors that contribute to tendon bowstringing at the proximal phalanx. We hypothesised that: (1) a partial rupture of the A2 pulley leads to significant bowstringing, (2) the location of the A2 rupture, starting proximally or distally, influences bowstringing, (3) an additional A3 pulley rupture causes a significant increase in bowstringing following a complete A2 pulley rupture and (4) the skin and tendon sheath may prevent bowstringing in A2 and A3 pulley ruptures.

METHODS

Index, middle and ring fingers of eight freshly frozen cadaver arms were used. A loading device pulled with 100 N force was attached to the flexor digitorum profundus (FDP). The flexor digitorum superficialis (FDS) was preloaded with 5 N. Bowstringing was measured and quantified by the size of the area between the FDP tendon and the proximal phalanx over a distance of 5 mm with ultrasonography (US).

RESULTS

US images showed that already a 30% excision of the A2 pulley resulted in significant bowstringing. In addition, a partial distal incision of the A2 pulley showed significantly more bowstringing compared to a partial proximal incision. Additional A3 pulley incision and excision of the proximal tendon sheath did not increase bowstringing. Subsequently, removing the skin did increase the bowstringing significantly.

CONCLUSION

A partial A2 pulley rupture causes a significant bowstringing. A partial rupture of the A2 pulley at the distal rim of the A2 pulley resulted in more bowstringing than a partial rupture at the proximal rim.

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.

Flexor tendon pulley injury in a bowler

Closed traumatic flexor injuries of the hand involving the pulley mechanism are a relatively common injury seen in rock climbers but are very rare in nonclimbers, including bowlers. The injury was first described in 1990. Since then, several studies have shed more light on the diagnostic and therapeutic considerations. Early diagnosis of pulley injuries is crucial since delayed diagnosis can lead to limited range of motion, particularly at the proximal interphalangeal joint. Flexion contractures at the proximal interphalangeal joint have also been cited in the literature. We discuss a case of pulley injury in a bowler and briefly review the anatomy of the pulley architecture, mechanism of injury, imaging manifestations, and clinical management of this injury.

The flexor tendon pulley system and rock climbing

Rock climbing has increased in popularity over the past two decades. Closed traumatic rupture of the finger flexor tendon pulleys is rare among the general population but is seen much more commonly in rock climbers. This article reviews the anatomy and biomechanics of the finger flexor tendon pulleys, how they may be injured in rock climbing and how these injuries are best diagnosed and managed.

DYNAMICS OF A2 FINGER PULLEY RUPTURE

A mathematical model of the A2 pulley system will enable us to have a better understanding of the mechanics of the pulley-tendon system and provide us with insights of the pulley rupture mechanism. The A2 pulley was modeled based on parallel pulley fibers attached to a phalanx with a tendon passing them. Mechanical properties of the pulleys such as stiffness, strength and friction were included in the model. A convergence test was done to ensure the accuracy of the test. The model managed to show high loads on flexed finger may lead to pulley ruptures. Further studies on the rupture mechanism showed that pulley ruptures are self-propagating when a constant force is applied and the rate of rupture increases, as fewer intact fibers are present to support the load. The initial rate of propagation is much slower and this accelerates as more fibers are ruptured. This explains the common occurrence of partial pulley ruptures.

Diagnosis of finger flexor pulley injury in rock climbers: A systematic review

BACKGROUND

Closed injury to the finger flexor pulley system is found frequently in rock climbers. There are no evidence-based published guidelines on the diagnosis and treatment of these injuries.

OBJECTIVES

THE PRESENT SYSTEMATIC REVIEW WAS UNDERTAKEN TO ANSWER THE FOLLOWING QUESTIONS: what are the most commonly recommended diagnostic criteria for finger flexor pulley injury in rock climbers; and, based on the available evidence, what is the best diagnostic test for these injuries?

METHODS

Four electronic databases were searched using specific key terms, with limits set for language and date. Two reviewers independently identified potentially relevant titles based on inclusion criteria. Inter-reviewer variability was assessed using the Kappa statistic. The scientific quality of articles was assessed using validated scales.

RESULTS

Of the 93 articles identified, 29 were included in the present analysis. The inter-rater agreement for selection of potentially relevant titles was 88% (kappa=0.74). The most commonly cited diagnostic criterion for closed finger pulley injury was clinical bow-stringing of the flexor tendons over the volar aspect of the proximal interphalangeal joint. However, the best study of diagnostic accuracy for these injuries supports the use of dynamic ultrasound.

CONCLUSIONS

Dynamic ultrasound is recommended for the diagnosis of closed finger pulley injuries in rock climbers. The prevailing notion that these injuries can be diagnosed by testing for clinical bowstringing is not supported by evidence.

[Subcutaneous avulsion of the flexor digitorum profundus muscle]

The diagnostic and treatment of a closed avulsion of the flexor digitorum profundus muscle at its insertion of the little finger is presented. This happened as a 41-year-old woman wanted to hold a dog lead in her left hand and suddenly the dog started to run. In the literature the flexor digitorum profundus (FDP) and flexor pollicis longus (FPL) tendons were found to be more frequently ruptured than the flexor digitorum superficialis tendon. Closed ruptures of the FDP have been rarely reported. In the case described here there was no torn fragment at the distal end of the FDP tendon and the bone structure of the phalanx distales was intact. The operative treatment, postoperative care and clinical course are presented.

The influence of concentric and eccentric loading on the finger pulley system

In this study we investigated the influence of the loading condition (concentric vs. eccentric loading) on the pulley system of the finger. For this purpose 39 cadaver finger (14 hands, 10 donors) were fixed into an isokinetic loading device. The forces in the flexor tendons and at the fingertip were recorded. In the concentric loading condition A2 and A4 ruptures as well as alternative events such as fracture of a phalanx or avulsion of the flexor tendons were almost equally distributed, whereas the A2 pulley rupture was the most common event (59%) in the eccentric loading condition and alternative events were rare (23.5%). The forces in the deep flexor tendon, the fingertip and in the pulleys were significantly lower in the eccentric loading condition. As the ruptures occurred at lower loads in the eccentric than in the concentric loading condition it can be concluded that friction may be an advantage for climbers, supporting the holding force of their flexor muscles but may also increase the susceptibility to injury.

Optimal 3-T MRI for depiction of the finger A2 pulley: comparison between T1-weighted, fat-saturated T2-weighted and gadolinium-enhanced fat-saturated T1-weighted sequences

OBJECTIVE

To compare three spin-echo sequences, transverse T1-weighted (T1WI), transverse fat-saturated (FS) T2-weighted (T2WI), and transverse gadolinium-enhanced (Gd) FS T1WI, for the visualisation of normal and abnormal finger A2 pulley with magnetic resonance (MR) imaging at 3 tesla (T).

MATERIALS AND METHODS

Sixty-three fingers from 21 patients were consecutively investigated. Two musculoskeletal radiologists retrospectively compared all sequences to assess the visibility of normal and abnormal A2 pulleys and the presence of motion or ghost artefacts.

RESULTS

Normal and abnormal A2 pulleys were visible in 94% (59/63) and 95% (60/63) on T1WI sequences, in 63% (40/63) and 60% (38/63) on FS T2WI sequences, and in 87% (55/63) and 73% (46/63) on Gd FS T1WI sequences when read by the first and second observer, respectively. Motion and ghost artefacts were higher on FS T2WI sequences. Seven among eight abnormal A2 pulleys were detected, and were best depicted with Gd FS T1WI sequences in 71% (5/7) and 86% (6/7) by the first and the second observer, respectively.

CONCLUSION

In 3-T MRI, the comparison between transverse T1WI, FS T2WI, and Gd FS T1WI sequences shows that transverse T1WI allows excellent depiction of the A2 pulley, that FS T2WI suffers from a higher rate of motion and ghost artefacts, and transverse Gd FS T1WI is the best sequence for the depiction of abnormal A2 pulley.

Finger A2 Pulley Lesions in Rock Climbers

OBJECTIVES

To evaluate magnetic resonance imaging (MRI) at 3 T in the diagnosis and characterization of lesions of the finger flexor A2 pulley in patients with clinically suspected A2 pulley lesions.

MATERIALS AND METHODS

Eight consecutive patients with clinically suspected lesions of the A2 pulley were included in this retrospective study. 3 T MRI was performed with T1-weighted, T2-weighted fat suppressed, and T1-weighted fat suppressed contrast enhanced sequences. The A2 pulley of all the fingers visible on the images were analyzed and pulley lesions characterized.

RESULTS

All asymptomatic pulleys were normal at MRI. In the 8 symptomatic fingers 7 pulleys were abnormal at MRI. With the clinical examination as gold standard, sensitivity, specificity, positive predictive value, and negative predictive value of MRI were 87.5%, 100%, 100%, and 95.2% respectively. Characterization of the different pulley lesion was possible.

CONCLUSION

MRI at 3 T allows reliable direct visualization and characterization of traumatic A2 pulley lesions.

Reconstruction of the digital flexor pulley system: a retrospective comparison of two methods of treatment

The rare injury of closed rupture of the A2 and A3 flexor pulleys was treated using two non-encircling techniques of pulley reconstruction. Thirteen patients were treated with an extensor retinaculum graft (Group A). At a mean follow-up time of 48 months, the average PIP flexion was 97%, the power grip strength 96%, the pinch grip strength 100% and the thickening 94% of the uninjured side. Ten patients were treated with a free palmaris longus tendon grafts (Group B). At a mean follow-up time of 57 months, the average PIP flexion was 94%, the power grip strength 98%, the pinch grip strength 100% and the thickening 95% of the uninjured side. In both groups, finger extension was unrestricted. The Buck Gramcko score included 10 excellent, two good and one fair result in Group A and seven excellent, two good and one fair result in Group B. Both techniques proved beneficial. All climbers returned to their previous standard and all non-climbers regained full finger dexterity in their previous job.

Impact of Taping after Finger Flexor Tendon Pulley Ruptures in Rock Climbers

Flexor tendon pulley ruptures are the most common injury in rock climbers. Therapeutic standards usually include a prolonged use of taping applied as a replacement for the lost pulley in a circular fashion at the base of the proximal phalanx. Our biomechanical considerations, however, suggest a new taping method, the H-tape. The purpose of the study is to evaluate whether this new taping method can effectively change the course of the flexor tendon and therefore reduce the tendon–bone distance. In order to compare the effects of different taping methods described in the literature with the newly developed taping method, we performed standardized ultrasound examinations of 8 subjects with singular A2 pulley rupture and multiple pulley ruptures of A2 and A3 pulleys and determined the respective tendon–bone distance for the different taping methods, versus without tape at a preset position on the proximal phalanx. In a second approach, we evaluated the effect of the new taping method on the strength of the injured finger using a force platform on 12 subjects with different pulley ruptures with injuries older than 1 year. The new taping method decreased the tendon–bone distance in the injured finger significantly by 16%, whereas the other taping methods did not. The strength development was significantly better with the new tape for the crimp grip position (+13%), but there was no significant improvement for the hanging position. We recommend taping with the newly presented taping technique after pulley rupture.

Injuries of the fingers and thumb in the athlete

Injuries of the fingers and thumb in the athlete are common. Mallet finger, jersey finger, boutonniere deformity, Bennett and Rolando fractures, and gamekeeper's thumb are just a few of the injuries that can occur in athletes. A thorough understanding of the mechanism of injury, osseous and soft tissue abnormalities, imaging features, and treatment is important in the care of athletes. Prompt and accurate diagnosis is important and may help minimize outcomes of malunion, posttraumatic arthritis, and debility.

Strength measurement and clinical outcome after pulley ruptures in climbers

PURPOSE

Ruptures of the finger flexor pulleys are the most frequent injuries in rock climbers. Whereas multiple pulley injuries demand a surgical reconstruction, single ruptures are mainly treated conservatively. Nevertheless, the question of the clinical outcome or a persisting finger strength deficit after conservative therapy arises.

METHODS

Twenty-one rock climbers (age 34 +/- 9 yr) with a grade 2-4 pulley injury were reevaluated 3.46 (range: 0.25-18) yr after injury. The clinical evaluation followed a standard questionnaire in combination with an ultrasound examination in extension and forced flexion. In order to determine the finger strengths, the subjects hung with the respective finger in various postures on a ledge attached above a door frame, while standing on a force platform, which measured the relative release.

RESULTS

The 21 subjects had old (3.46 yr, range: 0.25-18) pulley injuries in 27 fingers (10 A2, 1 A3, 11 A4, 3 A2/3, 2 A3/4). The clinical outcome was excellent (Buck-Gramcko score of 3) in all cases; the subjects regained their climbing level within a year. There was no difference between the initial ultrasound examination and the follow-up during the study. For 17 finger pairs, data for the relative strength of the injured and the respective healthy finger could be gathered. The finger strength was not significantly different for the injured and the healthy finger in either the hanging or the crimping finger position.

CONCLUSIONS

Nonsurgical treatment of single pulley ruptures is recommended. The clinical outcome was good to excellent, and no long-term strength deficit for the injured finger could be observed.

Closed flexor pulley injuries in nonclimbing activities

Closed flexor pulley injuries have been reported in rock climbers. We report 6 digital flexor pulley injuries in 6 patients aged 5 to 73 years that were not associated with a climbing injury. Excellent outcomes were achieved through conservative therapy in 5 patients and surgical therapy in 1 patient.

Injuries to the finger flexor pulley system in rock climbers: current concepts

Closed traumatic ruptures of finger flexor tendon pulleys began to be recognized specifically over the past several decades. This injury, although rare in the general population, is seen more commonly in rock climbers. This article analyzes this type of injury and the current diagnostic and therapeutic criteria. Ultrasound and magnetic resonance imaging are used to differentiate between a pulley strain, partial rupture, complete rupture, or multiple ruptures. Grade I to III injuries (strains, partial rupture, single ruptures) are treated conservatively with initial immobilization and early functional therapy under pulley protection. Grade IV injuries (multiple ruptures) require surgical repair.

MR imaging of the finger tendons: Normal anatomy and commonly encountered pathology

MR imaging has emerged as a powerful tool in the evaluation of soft tissue structures such as the tendons of the hand and finger due to its excellent soft tissue contrast and multiplanar imaging capabilities. In the finger and hand, perhaps more than in any other location in the body, a detailed and intimate understanding of anatomy is crucial for lesion localization, directing clinical management and predicting long-term prognosis. These issues are of paramount importance to both the clinician and imager, both faced with the challenge of the complex anatomy and pathology associated with these delicate structures. The anatomy of the finger including intrinsic and extrinsic muscles, retinacular structures, and tendons will be discussed. The MR imaging features of common lesions of the tendons of the hand and finger will be reviewed.

[High frequency sonography in the detection of finger injuries in sport climbing]

Sport climbing shows an increasing popularity, including even school sport activity on high climbing levels. Climbing related injuries are predominantly located in fingers/ hands ("climber's finger"), and can present as annular pulley rupture or more common as overuse injury. Beside clinical examination imaging modalities such as MRI and high frequency sonography have shown to allow for detection of climbing related injuries. High frequency sonography enables for exact differential diagnosis of climbing related finger/hand injuries and therefore plays a central role in adequate therapeutic management.

Friction between human finger flexor tendons and pulleys at high loads

A method was developed to indirectly measure friction between the flexor tendons and pulleys of the middle and ring finger in vivo. An isokinetic movement device to determine maximum force of wrist flexion, interphalangeal joint flexion (rolling in and out) and isolated proximal interphalangeal (PIP) joint flexion was built. Eccentric and concentric maximum force of these three different movements where gliding of the flexor tendon sheath was involved differently (least in wrist flexion) was measured and compared. Fifty-one hands in 26 male subjects were evaluated. The greatest difference between eccentric and concentric maximum force (29.9%) was found in flexion of the PIP joint. Differences in the rolling in and out movement (26.8%) and in wrist flexion (14.5%) were significantly smaller. The force of friction between flexor tendons and pulleys can be determined by the greater difference between eccentric and concentric maximum force provided by the same muscles in overcoming an external force during flexion of the interphalangeal joints and suggests the presence of a non-muscular force, such as friction. It constitutes of 9% of the eccentric flexion force in the PIP joint and therefore questions the low friction hypothesis at high loads.

MR imaging of ligament and tendon injuries of the fingers

Magnetic resonance (MR) imaging can provide important information for diagnosis and evaluation of soft-tissue trauma in the fingers. An optimal imaging technique should include proper positioning, dedicated surface coils, and specific protocols for the suspected abnormalities. Familiarity with the fine anatomy of the normal finger is crucial for identifying pathologic entities. MR imaging is a powerful method for evaluating acute and chronic lesions of the stabilizing articular elements (volar plate and collateral ligaments) of the fingers and thumbs, particularly in the frequently affected proximal interphalangeal and metacarpophalangeal joints. As in other body regions, MR imaging is also useful for depicting traumatic conditions of the extensor and flexor tendons, including injuries to the pulley system. In general, normal ligaments and tendons have low signal intensity on MR images, whereas disruption manifests as increased signal intensity. Radiologists need to understand the full spectrum of finger abnormalities and associated MR imaging findings.

Finger pulley injuries in extreme rock climbers: depiction with dynamic US

PURPOSE

To determine the ability of dynamic ultrasonography (US) to depict finger pulley injuries in extreme rock climbers.

MATERIALS AND METHODS

Sixty-four extreme rock climbers (climbing levels 8-11 on a scale ranging from 1 to 11; Union Internationale des Associations d'Alpinisme) with finger injuries (75 symptomatic and 181 asymptomatic fingers) were examined by using US, with the transducer operating at 12 MHz. The distance between the flexor tendon and phalanx was evaluated in extension and forced flexion at the level of the A2 and A4 annular pulleys as an indicator of tendon bowstringing. A distance between the flexor tendon and phalanx greater than 1.0 mm was interpreted as positive for a pulley injury. US findings were compared with those of magnetic resonance imaging. Surgical correlation was available in seven cases. Statistical analysis was performed by using analysis of variance, the Student t test, and the Bonferroni method.

RESULTS

US depicted 16 (100%) of 16 complete A2 pulley ruptures, nine (100%) of nine complete A4 pulley ruptures, six (86%) of seven surgically proved complete combined A2 and A3 pulley ruptures, and 15 (100%) of 15 incomplete A2 pulley ruptures. Measurement of distance between the flexor tendon and phalanx was significantly different among patient subsets without pulley ruptures and those with incomplete, complete, or complete combined pulley ruptures (P <.001). The sensitivity of US for depiction of finger pulley injuries was 98%, and specificity was 100%.

CONCLUSION

Dynamic US allows excellent depiction of finger pulley injuries in extreme rock climbers.

Closed traumatic rupture of the flexor pulleys of a long finger associated with avulsion of the flexor digitorum superficialis

We report a closed rupture of the second, third and fourth annular pulleys associated with avulsion of the flexor digitorum superficialis tendon in the ring finger of a healthy, 48-year-old patient. It was caused by sudden and violent flexion of the finger and led to a serious impairment of the proximal interphalangeal joint motion, despite physiotherapy and dynamic splinting. The patient was treated surgically, 3 months after the injury, with reconstruction of the second (A2) and fourth (A4) annular pulleys and excision of the distal portion of the superficialis tendon. The final functional result was satisfactory.

Pulley system in the fingers: normal anatomy and simulated lesions in cadavers at MR imaging, CT, and US with and without contrast material distention of the tendon sheath

PURPOSE

To describe the normal anatomy of the finger flexor tendon pulley system, with anatomic correlation, and to define criteria to diagnose pulley abnormalities with different imaging modalities.

MATERIALS AND METHODS

Three groups of cadaveric fingers underwent computed tomography (CT), magnetic resonance (MR) imaging, and ultrasonography (US). The normal anatomy of the pulley system was studied at extension and flexion without and with MR tenography. Pulley lengths were measured, and anatomic correlation was performed. Pulley lesions were created and studied at flexion, extension, and forced flexion. Two radiologists reviewed the studies in blinded fashion.

RESULTS

MR imaging demonstrated A2 (proximal phalanx) and A4 (middle phalanx) pulleys in 12 (100%) of 12 cases, without and with tenography. MR tenography showed the A3 (proximal interphalangeal) and A5 (distal interphalangeal) pulleys in 10 (83%) and nine (75%) cases, respectively. US showed the A2 pulley in all cases and the A4 pulley in eight (67%). CT did not allow direct pulley visualization. No significant differences in pulley lengths were measured at MR, US, or pathologic examination (P: =.512). Direct lesion diagnosis was possible with MR imaging and US in 79%-100% of cases, depending on lesion type. Indirect diagnosis was successful with all methods with forced flexion.

CONCLUSION

MR imaging and US provide means of direct finger pulley system evaluation.

The use of a graft from the second extensor compartment to reconstruct the A2 flexor pulley in the long finger

A 10 mm wide ring graft from the second extensor compartment with periosteum from the floor of the sheath was used to correct bowstringing in six patients who sustained an isolated rupture of the A2 pulley. It was attached to the lateral rims of the sheath. Periosteum was used for additional graft fixation. Bowstringing was assessed by magnetic resonance imaging and ultrasound preoperatively and 19.5 months after surgery. It was corrected in five patients and improved in one. Pain was reduced from 35 to 7 points on a visual analogue scale. Digital circumference decreased from 76 to 71 mm. Flexion at the PIP joint increased from 88 degrees to 116 degrees. Pinch grip improved from 28 to 56 N.