The climber's finger : imaging of finger flexor tendon pulley injuries.

ObjectiveTo 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 Methods30 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.ResultsIn 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).ConclusionMRI 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.

Objectives: This systematic review addressed the following questions: what are the most recommended diagnostic criteria for pulley injuries in finger flexors among climbers? What is the best functional or classification clinical test for these injuries based on the available evidence? Materials and Methods: Following the PRISMA Statement checklist, a systematic literature review was conducted between August and September 2023, using a search on the PubMed database with a string of keywords and MeSH terms. The PEDro scale was used to analyze bias in the individual studies examined. Conclusions: Based on the exclusion criteria and research question, 14 articles with heterogeneous study designs were selected. Studies involving diagnosis through clinical examination or instrumental tests were analyzed. The data obtained provide an overview of different diagnostic and classification criteria for the injury under consideration. Ultrasounds remain the gold standard in diagnosing finger pulley injuries. The distance between the tendon and bone is the most used diagnostic criterion, with a distance greater than 2 mm corresponding to an A2 or A4 pulley injury. The clinical sign of bowstringing coincides with a multiple pulley injury involving A2, A3, and A4. Clinical signs, ultrasounds, and grip strength should be evaluated for a comprehensive diagnosis. A grip deficit of 41.4% corresponds to a pulley injury.

The trigger finger is one of the leading causes of finger pain and triggering. The flexor tendons are stabilized by a fibrous band called the annular pulley. The first annular pulley (A1 pulley) is located at the level of the metacarpophalangeal joint. Trigger finger is characterized by thickening of the A1 pulley. There is a lack of clinical and ultrasonographic risk factors that may help clinicians. The main purpose of the study was to measure the thickness of the flexor tendon and A1 pulley in patients with trigger finger compared to healthy volunteers and to reveal risk factors of trigger finger. The study included 30 healthy volunteers and 30 patients with trigger fingers. The thickness of the flexor tendon and A1 pulley were measured using ultrasound. Multiple regression analysis was also conducted. In the healthy group, the mean thickness of the flexor tendon and A1 pulley were 3.21 ± 0.64 and 0.40 ± 0.09 mm, respectively. In the TF group, the mean thickness of the flexor tendon and A1 pulley were 3.78 ± 0.86 and 0.49 ± 0.16 mm, respectively. The differences were statistically significant (p = 0.010 and p = 0.009, respectively). The mean thickness of the flexor tendon and A1 pulley of trigger finger were significantly higher than adjacent and contralateral healthy digits of the patients with trigger finger (p = 0.001, p = 0.001, p = 0.019, p = 0.002, respectively). The risk of trigger finger was found to be 11.5 times higher in diabetic patients, 3.734 times higher in patients with a history of hand forcing, 2.912 times with a 1 mm increase in flexor tendon thickness, and 1.724 times with an increase of 0.1 mm in A1 pulley thickness. In this study, the flexor tendon and A1 pulley were found to be more thickened in the trigger finger group compared to the controls. Diabetes mellitus, history of hand forcing, increased tendon, and A1 pulley thickness are among the risk factors associated with trigger finger. Ultrasound Features of Trigger Finger, Registry number: NCT05675488.

Pulley injuries in rock climbers.

Finger Flexor Pulley Injuries in Rock Climbers.

In sport climbing, and particularly in rock climbing, the so-called crimp grip position is the finger position most often used to enable the athlete to hold the smallest ledges. The proximal interphalangeal (PIP) joints are thereby flexed at approximately 90 degrees, and the distal interphalangeal joints are hyperextended. In this position, the force transmission from the flexor tendon to the A2 and A4 pulley is at its maximum, and the load at the pulleys is approximately four times higher than at the fingertip. The use of the crimp grip may lead to tendosynovitis and partial or complete ruptures of the A2 and A4 pulley, particularly if warming up has not been conducted properly, which should involve at least 100 climbing moves. Under maximal load, the friction between the flexor tendons and the A2 pulley is responsible for up to 18 per cent of the grip force. Friction correlates with the degree of PIP joint flexion, which is maximal at approximately 90 degrees. Pulley injuries are mostly due to the bowstringing of the flexor tendon and peak forces at the edges of the A2 and A4 pulleys. However friction may also play an important role in the pathogenesis in a way that the tendon acts like a saw crossing the pulley fibers. These findings also explain why pulley injuries often occur during crimp grip and during a sudden and high eccentric load at the PIP joint. Friction between the tendons and pulleys may also physiologically act as a substantial part of the holding force, particularly in static or eccentric flexion of the PIP joint, and may increase the maximum muscular holding force. Friction therefore has to be taken into account as an important factor in the biomechanics of finger modeling in sport climbing and the explanation of the pathophysiology of pulley injuries.

Finger flexion contractures are an important cause of disability in patients with systemic sclerosis; however, their pathophysiology is poorly understood. Our aim was to assess the feasibility of scanning finger flexor tendons in patients with systemic sclerosis and explore the ultrasound findings in these tendons, including measurement of finger flexor tendon complex. Grey-scale and power Doppler ultrasound assessment of the finger flexor tendon complex including tendon structure and surrounding soft tissue. Measurements of the finger flexor tendon complex (A1 pulley, tendon and palmar plate) were made. Feasibility was assessed by the number of fingers which could be measured. We studied the second to fifth flexor tendons (n = 160) of both hands in 20 patients with systemic sclerosis, including early and established disease. We were able to assess the finger flexor tendon complex and make measurements of the flexor tendon and palmar plate in all (n = 40) and A1 pulley in almost all (n = 39) of the studied fingers. Common pathologies identified included peritendinous (n = 12) and soft tissue (n = 8) calcification. Tendon thickening was seen in six patients, but synovitis/tenosynovitis was rare. The A1 pulley was thickened in patients with systemic sclerosis (0.46 mm), in particular, those with diffuse cutaneous systemic sclerosis (0.50 mm). We were able to successfully assess, including making measurements of, the finger flexor tendon complex in patients with systemic sclerosis. Our study showed calcifications in the peritendinous areas and soft tissue and thickening of the A1 pulley. These findings may play a role in the pathophysiology of systemic sclerosis-hand contractures by causing mechanical impingement of the finger flexion mechanism. This pilot study will guide future research to look for potential (treatable) causes of finger flexion contractures in patients with systemic sclerosis.

Introduction:Finger flexor tendon injuries commonly occur as a result of direct trauma. On rare occasions, spontaneous ruptures can occur. Many pathologic processes have been described in the literature contributing to spontaneous finger flexor tendon ruptures, with most leading to progressive weakening of the tendon until it ultimately fails. We present a unique case of a Zone III spontaneous combined flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP) rupture of the small finger in a 66-year-old female, 3 weeks after a corticosteroid injection for trigger finger. To the best of our knowledge, this is the only report of a small finger combined FDS/FDP rupture after a single corticosteroid injection.Case Report:A 66-year-old female presented with the inability to flex her right small finger for the past 4 days, after injuring it at the gym. She had previously received one corticosteroid injection into her small finger for the treatment of the trigger finger approximately 3 weeks prior. Magnetic resonance imaging revealed rupture of both finger flexors of the small finger at the level of the mid metacarpal shaft, with at least 1 cm of separation. Reconstruction of the small finger FDP was performed using the FDS as an intercalary graft without complication. At the 6-week follow-up visit, she was doing well, able to flex both her proximal and distal interphalangeal joints actively. She experienced some stiffness but had an almost complete range of motion. She was pleased with the results at that time.Conclusion:This case demonstrates a unique complication of non-operative treatment of trigger finger. While it will ultimately not change our institution’s treatment of trigger finger, it will lead to our team becoming more aware of the impact of corticosteroid injections and the need to inform patients to ease back into physical activity following injection.

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

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.

Background/Objectives: Rock climbing is becoming more popular, leading to an increased focus on diagnosing and treating related injuries. Finger pulley and flexor tendon injuries are common among climbers, with the A2 pulley being the most frequently affected. High-resolution ultrasound (US) is the preferred method for detecting pulley injuries. This study aimed to determine the reliability and validity of US in identifying anatomical landmarks for diagnosing A2 pulley ruptures. Methods: This study was cross-sectional, involving 36 fingers from 4 cadaver arms. A Canon Aplio i800 US machine was used to measure two anatomical landmarks: the midpoint of the proximal phalanx and the distal edge of the A2 pulley. For the first anatomical landmark, the length of the proximal phalanx (PP distance), and for the second landmark, the distance between the distal edges of the proximal phalanx and the A2 pulley ("A" distance), were measured. Measurements were performed by two sonographers and compared to a digital caliper measurement taken post-cadaver dissection. Observers were blinded during measurements to ensure unbiased results. Results: Overall PP distance measured by US (O1: 37.5 ± 5.3 mm, O2: 37.8 ± 5.4 mm) tended to be shorter than caliper measurements (O3: 39.5 ± 5.5 mm). The differences between sonographers were minimal, but larger when compared to caliper measurements. High reliability for PP distance measurement was observed, especially between sonographers, with an ICC average of 0.99 (0.98, 1.00). However, reliability was lower for the "A" distance, with significant differences between US and caliper measurements. Regarding validity, US measurements were valid when compared to caliper measurements for PP distance, but not as reliable for the "A" due to wider confidence intervals. While US can substitute caliper measurements for PP distance (LR, Y:O2, X:O3, -0.70 (-3.28-1.38), 0.98 (0.93 ± 1.04)), its validity for "A" distance is lower (LR, Y:O2, X:O3, -2.37 (-13.53-4.83), 1.02 (0.62-1.75)). Conclusions: US is a reliable and valid tool in identifying anatomical landmarks for diagnosing A2 pulley ruptures, particularly for detecting the midpoint of the proximal phalanx. This is important to differentiate between complete and partial A2 pulley tears. However, the measurement of the "A" distance requires further refinement. These findings support efforts to standardize US examination protocols and promote consensus in diagnostic methodology, though further research is needed to address the remaining challenges.

Diagnosis of Complex Pulley Ruptures Using Ultrasound in Cadaver Models

0614: Pulleys, Plates and Other Paraphernalia - Anatomy and Unique Injuries to Fingers

Pulley ruptures are the most common injuries in sport climbing. Ruptures of the A2 and A4 pulleys have been studied extensively, and ultrasound has proven to be a highly sensitive and specific tool for their diagnosis. However, the correct diagnosis of A3 pulley ruptures continues to be a challenge. Therefore, we investigated a novel approach to this pathology. Eighteen fingers from nine different human cadavers were examined using high-resolution, dynamic ultrasound before and after being subjected to different combinations of singular and multiple iatrogenic pulley ruptures in a standardised fashion. Special attention was paid to the behaviour of the volar plate (VP) with respect to the proximal interphalangeal joint (PIP) and the flexor tendons before and after pulley rupture. Injuries to the A2 and A4 pulleys were diagnosed via ultrasound with sensitivities of 90 % and 94 % and specificities of 100 % and 97 %, respectively. A direct visualisation of the A3 pulley was achieved in 61 % of the fingers. The VP became significantly thicker and shorter during finger flexion as well as after A3 pulley rupture. The distance between tendon and VP became significantly more pronounced after A3 pulley rupture. For distances greater than 0.9 mm between VP and tendon, a sensitivity of 76 % and a specificity of 94 % were achieved for determining A3 pulley ruptures. The distance measurement between VP and tendon was found to be a valid indirect method for the diagnosis of A3 pulley ruptures. This approach is the first ultrasound method for accurately diagnosing A3 pulley ruptures.

The ability of finger flexors to generate force has been studied in relation to climbing performance. However, not much attention has been paid to the decrease in finger grip force in relation to annular pulley injuries. The purpose of the present study was to determine if an injured annular pulley implies a finger flexor force decrease, as well as its relation to clinical and sonographic changes. We performed an observational study in 39 rock climbers with A2 or A4 pulley injuries to the 3rd or 4th fingers. The variables considered were pain upon palpation, ultrasound tendon–bone distance, and finger grip strength decrease. Three rock climbing grip types were considered: the one finger crimp, open crimp, and close crimp. Injured rock climbers presented a decrease in finger grip strength compared to non-injured controls when performing a one finger crimp (p < 0.001). There exists a significant correlation between a tendon–bone distance at the level of the injured pulley and a decreased finger grip strength measured by performing a one finger crimp (p = 0.006). A decrease in finger grip strength could be considered in the diagnostic and follow-up process of A2 and A4 pulley injuries to the 3rd and 4th fingers.