Friction between finger flexor tendons and the pulley system in the crimp grip position

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.

A Biomechanical Analysis of the H-Taping Method Used by Rock Climbers as Prophylactic or Stabilizing Fixation of Partial A2 Pulley Tears

PURPOSE

Rock climbing can lead to upper-extremity injuries, such as A2 pulley ruptures, leading to the bowstringing of the flexor tendons. Climbing finger positions are specific and can put undue stress on the pulley systems. This causes severe hand dysfunction and is a difficult problem to treat, and prevention is important. Using a cadaveric, experimental model, we evaluated the effectiveness of the H-taping method, commonly used by rock climbers, to prevent and treat A2 pulley tears.

METHODS

Using fourteen matched pairs of fresh-frozen cadaveric hands with forearms, four experiments were conducted with 56 paired comparisons evaluating the failure force, fingertip force, and mode of failure (112 total tests). Comparisons were as follows: index fingers- intact versus 50% distal A2 pulley tears without H-taping (control); ring fingers- intact versus H-taping as a prophylactic for A2 pulley tears; little fingers- 50% distal A2 pulley tears with H-tape versus without tape; and middle fingers- H-taping as a prophylactic versus H-taping as a stabilizing treatment of torn pulleys.

RESULTS

The mean index finger failure force was significantly higher in intact vs torn A2 pulleys (control). Failure force for intact H-taped fingers was significantly higher than torn H-taped fingers, but no other finger comparisons for failure force were significant. There were no significant findings in comparison of mean fingertip force values in any of the experiments.

CONCLUSIONS

We found that H-taping is not effective as prophylaxis against A2 pulley ruptures or as a stabilizing treatment method for partially ruptured pulleys.

CLINICAL RELEVANCE

While H-taping has not been recommended as prophylaxis for preventing A2 pulley ruptures, the climbing community has embraced this technique as a preventative measure. The present study provides biomechanical evidence against H-taping for this purpose. Furthermore, it does not appear to aid in increasing fingertip force after injury.

A Life Dedicated to Climbing and Its Sequelae in the Fingers-A Review of the Literature

Fingers of sport climbers are exposed to high mechanical loads. This work focuses on the fingers of a 52-year-old active elite climber who was the first in mankind to master 8B (V13), 8B+ (V14) and 8C (V15) graded boulders, bringing lifelong high-intensity loads to his hands. It is therefore hypothesized that he belongs to a small group of people with the highest accumulative loads to their fingers in the climbing scene. Fingers were analyzed by means of ultrasonography, X-rays and physical examination. Soft tissue and bone adaptations, as well as the onset of osteoarthritis and finger stiffness, were found, especially in digit III, the longest and therefore most loaded digit. Finally, this article aims to provide an overview of the current literature in this field. In conclusion, elite sport climbing results in soft tissue and bone adaptations in the fingers, and the literature provides evidence that these adaptations increase over one's career. However, at later stages, radiographic and clinical signs of osteoarthritis, especially in the middle finger, seem to occur, although they may not be symptomatic.

Upper Extremity Injuries in Rock Climbers: Diagnosis and Management

Rock climbing places substantial stress on the upper extremities and can lead to unique injuries not common to other sports. With increasing popularity of the sport, hand surgeons are expected to see more patients with these pathologies. An understanding of the sport, accurate diagnoses, and appropriate treatment protocols are critical to maintain climbers' competitive abilities.

Cortical Bone Thickness, Base Osteophyte Occurrence and Radiological Signs of Osteoarthritis in the Fingers of Male Elite Sport Climbers: A Cross-Sectional 10-Year Follow-Up Study

Background: Sport climbing places high mechanical loads on fingers. In 2012, our research group demonstrated adaptations of climbers’ cortical bones with the presence of osteophytes compared to non-climbing controls.

Objectives: 1) To investigate 10-year changes in cortical bone thickness, base osteophyte occurrence and radiological signs of osteoarthritis in the fingers of elite male sport climbers with more than 25 years of climbing history and 2) to compare cortical bone thickness, base osteophyte occurrence and radiological signs of osteoarthritis between male sport climbers and age-matched controls at the 10-year follow-up.

Methods: All 31 elite sport climbers who participated in both the baseline and 10-year follow-up assessments (follow-up rate 100%) were examined by means of X-rays. Cortical bone thickness, presence of osteophytes and signs of osteoarthritis according to Kellgren-Lawrence were obtained and compared to the baseline values 10 years earlier and to age-matched controls at the follow-up (n = 15).

Results: Significantly increased cortical bone thickness over the past 10 years was observed in climbers (mean absolute difference with 95% CI:0.98 mm (0.77 mm, 1.19 mm); p <0.001). Moreover, compared to age-matched controls, climbers had significantly thicker cortical bone at the 10-year follow-up (mean absolute difference with 95% CI:0.86 mm (0.61 mm, 1.12 mm); p <0.001). In climbers, osteophytes and clear signs of osteoarthritis were mainly seen in DIP joints. Signs of osteoarthritis according to Kellgren-Lawrence were more prevalent than 10 years before in most joints. In lateral radiographs, base osteophytes were not significantly more prevalent than 10 years before in most of the joints. The percentage of climbers who had osteophytes in any DIP (PIP) joint increased from 93.5% (67.7%) at baseline to 100% (74.2%) at the 10-year follow-up. The percentage of climbers who had clear signs of osteoarthritis according to Kellgren-Lawrence in any DIP (PIP) joint increased from 12.9% (9.7%) at baseline to 74.2% (64.5%) at 10-year follow-up. Only a few such degenerative changes were found in age-matched controls.

Conclusion: An accumulation of repetitive climbing-related stress to the fingers of elite sport climbers over the career may induce lifelong mechano-adaptation of the cortical bone thickness of all phalanges. At the 10-year follow-up, a further significant increase in radiographic signs of osteoarthritic changes was observed.

Long term evolution of soft tissue response in the fingers of high-level sport climbers: A cross-sectional 10 Year follow-up study

BACKGROUND

Sport climbing induces physiological changes in the body of high-level climbers. In 2012, our study group demonstrated adaptions of elite climbers' soft tissues with thicker A2/A4-pulleys, flexor tendons and palmar plates compared to non-climbers.

OBJECTIVES

To assess these adaptations over time we examined all 31 (follow up 100%) climbers that participated in that baseline study again using ultrasonography after a follow-up of 10 years.

MAIN FINDINGS

(1) In climbers, a significant increase in A2 and A4-pulley and flexor tendon thickness over the last 10 years was observed (p < 0.001), while PIP&DIP palmar plate thickness remained unchanged (p > 0.05); (2) at 10-years follow-up, all soft tissue thickness parameters (incl. palmar plates) were still significantly larger in climbers than in age-matched controls (p < 0.05); (3) as for the association with anthropometrics and climbing performance/experience, a significant association of the current climber's soft tissue thickness could only be found between palmar plate and reached climbing level(p = 0.032) as well as climber's body weight(p = 0.004).

CONCLUSION

An accumulation of repetitive climbing-related stress to the fingers of elite sport climbers over the career induces mechano-adaptation of the A2/A4-pulleys, flexor tendons and palmar plates. At later stages, there is a further significant increase in flexor tendon and pulley thickness, but not for palmar plate thickness.

Longer Tendon-Bone Distances of the A2 and A4 Annular Pulleys in Experienced High-Level Sport Climbers: Injury or Adaptation?

INTRODUCTION

Experienced high-level climbers are subject to a number of bone and soft tissue changes over the years and are also among the most exposed to pulley injuries. One of the main consequences of pulley rupture is the separation of the flexor tendons from the subjacent phalanges, also known as bowstringing. The purpose of this study was to determine whether this population has asymptomatic bowstringing of the A2 and/or A4 pulleys as determined by tendon-bone distance (TBD) values when compared to nonclimbers.

METHODS

High-resolution ultrasound TBD measurements in active forced flexion were made for the A2 and A4 pulley of the ring finger bilaterally. Participants were 21 asymptomatic sport climbers who had 21 consecutive years of climbing at a level above 9.66 in the International Mountaineering and Climbing Federation difficulty metric scale. Control subjects were 21 age-matched nonclimbers.

RESULTS

A significantly longer TBD-25% (0.3 mm) and 35% (0.4 mm) for the A2 and A4 pulleys, respectively-was found in the experienced climbers group (experienced climbers group: A2 1.6±0.5 mm and A4 1.6±0.4 mm; nonclimbers group: A2 1.2±0.1 mm and A4 1.2±0.2 mm).

CONCLUSIONS

Our results suggest that bowstringing of A2 and A4 pulleys occurs in asymptomatic experienced high-level climbers, which could be interpreted as either an adaptive mechanism to workloads endured over years of climbing or a consequence of underdiagnosed pulley ruptures.

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.

Unusual rupture of the middle finger flexor digitorum superficialis tendon in a climber: Biomechanical analysis

Sport climbing is increasingly popular and consultations by climbers in hand surgery departments are on the increase. The pathologies related to this sport concern essentially the pulley system, tendons being rarely affected. We report the case of a male climber who presented an atypical rupture of the flexor superficialis tendon in his left middle finger sustained when using an atypical climbing grip technique: the "hook grip". This consists in extension of the metacarpophalangeal joints and maximal flexion of the proximal interphalangeal joints with force exerted only on middle phalanx of the middle finger. A biomechanical analysis using finger musculoskeletal modeling was performed to compare the hook grip to other grips, and the patient's recovery performance was assessed. Adapted functional treatment with physiotherapy seems to have been a good option for the treatment of this atypical lesion since the patient recovered normal use of his finger in daily life. He recovered maximal force in climbing holds. The biomechanical analysis confirmed that the atypical "hook grip" was likely at the origin of the rupture, since flexor digitorum superficialis tendon force for this grip is greater than in other climbing grip techniques. The "hook grip" seems to be dangerous and should be used cautiously by climbers to prevent similar pathology. Additionally, the patient should henceforth be careful when climbing, since the biomechanical model showed that the remaining flexor digitorum profundus tendon was overused.

A Potentially Inexpensive Diagnostic Method for A2 Pulley Ruptures

Injuries to the flexor pulley system of the hand, while uncommon, can be problematic and debilitating for patients. Current standards of diagnosis for A2 pulley disruptions often include costly imaging studies and inaccurate clinical testing. We present the case of a patient with an isolated complete A2 pulley avulsion that was diagnosed by employing a simple technique using a silicone wedding ring. A silicone wedding band was applied over the region of a suspected A2 pulley rupture, resulting in the immediate restoration of full range of motion as well as complete resolution of the injury after three months, without any need for surgical intervention. The usage of this ring confirmed an A2 pulley avulsion that was visualized on magnetic resonance imaging (MRI). The proposed “Wedding Band Test” is potentially an accurate and inexpensive diagnostic tool for clinical evaluation of A2 pulley ruptures.

Recovery of rock climbing performance after surgical reconstruction of finger pulleys

This study evaluated recovery of sport performance and correction of bowstringing after surgical reconstruction of closed finger pulley rupture in high-level rock climbers. A total of 38 patients treated with an extensor retinaculum graft were assessed. The mean follow-up time was 85 months, and 30 patients returned to their previous climbing level. The mean total active motion score was 96% of the opposite side. All patients had an excellent Buck-Gramcko score. There was no significant difference in grip strength and tip pinch strength in the crimp position between the injured side and the opposite side. A total of 31 patients were examined with ultrasonography. In 18, flexor bowstringing effects had returned to near-normal values. There was an association between rock climbing level recovery and the flexor bowstringing correction (odds ratio, 6.9; 95% confidence interval, 1.1-42.8). If flexor bowstringing was corrected, patients were more likely to regain their preinjury sport performance. The ultrasonography measurement was a useful tool for predicting functional recovery.

LEVEL OF EVIDENCE

4.

Proximal interphalangeal joint volar plate configuration in the crimp grip position

PURPOSE

To study the configuration of the proximal interphalangeal joint volar plate (VP) in the crimp grip position (metacarpophalangeal joint at 0° to 45° flexion, proximal interphalangeal joint at 90° to 100° flexion, and distal interphalangeal joint at 0° to 10° hyperextension) using magnetic resonance imaging techniques in healthy volunteers and cadaver fingers and to compare the results with histological sections.

METHODS

Magnetic resonance imaging was performed on 24 fingers of 8 healthy volunteers and 12 fingers of 4 embalmed cadaver hands in the neutral position and in the crimp grip position. The translation of the VP body relative to the middle phalanx base during finger flexion was measured. In 6 of 12 cadaver specimens, a load of 10 N was applied to the flexor tendons to examine how this would affect the histological VP fiber configuration.

RESULTS

When the flexor tendons were under load in the crimp grip position, the volunteers' VP body was translated an average of 3.2 mm, and the cadaver fingers' VP body was translated an average of 3.0 mm, relative to the middle phalanx base in a distal direction. Histological analysis of the crimp grip position revealed reversing fibers in the VP insertion at the base of the middle phalanx when the flexor tendons were under load and the VP body was translated. When no load was applied in the crimp grip position, no translation of the VP body occurred.

CONCLUSIONS

This article describes a VP translation in a distal direction relative to the middle phalanx base in the crimp grip position when the flexor tendons are under load.

CLINICAL RELEVANCE

A more precise knowledge of the histological properties of the proximal interphalangeal joint VP during finger flexion can be expected to provide greater diagnostic capabilities and can lead to a better comprehension of injuries.

Surgical repair of multiple pulley injuries--evaluation of a new combined pulley repair

PURPOSE

We report on a combined repair of multiple annular pulley tears using 1 continuous palmaris longus tendon graft to restore strength and function.

METHODS

We treated 6 rock climbers with grade 4 pulley injuries (multiple pulley injuries) using the combined repair technique and re-evaluated them after a mean of 28 months.

RESULTS

All patients had excellent Buck-Gramcko scores; the functional outcome was good in 4, satisfactory in 1, and fair in 1. The sport-specific outcome was excellent in 5 and satisfactory in 1. Proximal interphalangeal joint flexion deficit slightly increased in 1 patient and remained the same in the other 5. Climbing level after the injury was the same as before in 4 and decreased slightly in 2 climbers.

CONCLUSIONS

The technique is effective with good results and has since become our standard treatment. Nevertheless, it is limited in patients with flexion contracture of the proximal interphalangeal joint.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic III.

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.