Hand Pulleys: Difference between revisions

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== Definition/Description  ==
== Definition/Description  ==
[[File:Finger pulleys.jpg|right|frameless|150x150px]]
There are five flexor tendon pulleys in the fingers that are named A1-A5, and consists of annular ligaments pulleys, and cruciate pulleys ie The flexor tendon pulley system.  The thumb only has two pulleys that are described as A1 and A2. 
There are five flexor tendon pulleys in the fingers that are named A1-A5, and consists of annular ligaments pulleys, and cruciate pulleys ie The flexor tendon pulley system.  The thumb only has two pulleys that are described as A1 and A2. 


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=== Clinically Relevant Anatomy ===
=== Clinically Relevant Anatomy ===
The flexor pulley system (digital sheath) is formed by a  
The flexor pulley system (digital sheath) is formed by a  
[[File:1024px-1121 Intrinsic Muscles of the Hand Superficial sin.png|right|frameless|700x700px]]
# Retinacular component which condensates and are arranged in cruciform, annular pulleys and transverse patterns.  
# Retinacular component which condensates and are arranged in cruciform, annular pulleys and transverse patterns.  
2. Membranous, or synovial, lining (deep to the above)
2. Membranous, or synovial, lining (deep to the above)
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These components work in concert to produce smooth and efficient flexion of the individual digits of the hand.  
These components work in concert to produce smooth and efficient flexion of the individual digits of the hand.  
 
* Injury to the flexor tendon system can lead to significant morbidity for patients.<ref>Kaplan EB. Functional and Surgical Anatomy of the Hand. Philadelphia, JB Lippincott Co, 2nd Ed, 1965</ref><ref>Bone spine [https://boneandspine.com/flexor-tendon-pulley-system-of-hand/ Pulley system of hand] Available from:https://boneandspine.com/flexor-tendon-pulley-system-of-hand/ (last accessed 17.3.2020)</ref>
Injury to the flexor tendon system can lead to significant morbidity for patients.<ref>Kaplan EB. Functional and Surgical Anatomy of the Hand. Philadelphia, JB Lippincott Co, 2nd Ed, 1965</ref><ref>Bone spine [https://boneandspine.com/flexor-tendon-pulley-system-of-hand/ Pulley system of hand] Available from:https://boneandspine.com/flexor-tendon-pulley-system-of-hand/ (last accessed 17.3.2020)</ref>
* The most important ones are the A2 and the A4 pulleys<ref>Lin GT, Amadic PC, An KN, et al. Functional anatomy of the human digital flexor pulley system. J Hand Surg Am 14:949-956, 1989</ref>, situated at the palmar side of the digits. The A2 pulley is continuous with the periosteum of the proximal phalanx and the A4 pulley is in the middle of the middle phalanx.<ref name=":2" />  
 
* Image at R shows the annular and cruciform pulleys on index finger.
The most important ones are the A2 and the A4 pulleys<ref>Lin GT, Amadic PC, An KN, et al. Functional anatomy of the human digital flexor pulley system. J Hand Surg Am 14:949-956, 1989</ref>, situated at the palmar side of the digits. The A2 pulley is continuous with the periosteum of the proximal phalanx and the A4 pulley is in the middle of the middle phalanx.<ref name=":2" />  


== Diagnostic Procedures  ==
== Diagnostic Procedures  ==

Revision as of 07:45, 17 March 2020

Original Editors Curtil Louis

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Definition/Description[edit | edit source]

File:Finger pulleys.jpg

There are five flexor tendon pulleys in the fingers that are named A1-A5, and consists of annular ligaments pulleys, and cruciate pulleys ie The flexor tendon pulley system. The thumb only has two pulleys that are described as A1 and A2. 

Flexor pulley system consists of following

  • Palmar Aponeurosis Pulley
  • 5 Annular Pulleys
  • 3 Cruciform Culleys.

Together, these form a fibro-osseous tunnel on the palmar aspect of the hand through which passes the deep and superficial flexor tendons.

Flexor tendon pulley system maintains flexor tendons close to joint’s axis of motion and prevents bowstringing.

Clinically Relevant Anatomy[edit | edit source]

The flexor pulley system (digital sheath) is formed by a

1024px-1121 Intrinsic Muscles of the Hand Superficial sin.png
  1. Retinacular component which condensates and are arranged in cruciform, annular pulleys and transverse patterns.

2. Membranous, or synovial, lining (deep to the above)

The digital sheath serves following functions

  • Facilitates smooth gliding of the tendons
  • Pulleys from retinacular component provide a mechanical advantage to flexion
  • Synovial fluid bathes and provides nutrition.

The flexor tendon system of the hand consists of the flexor muscles of the forearm, their tendinous extensions, and the specialized digital flexor sheaths.

These components work in concert to produce smooth and efficient flexion of the individual digits of the hand.

  • Injury to the flexor tendon system can lead to significant morbidity for patients.[1][2]
  • The most important ones are the A2 and the A4 pulleys[3], situated at the palmar side of the digits. The A2 pulley is continuous with the periosteum of the proximal phalanx and the A4 pulley is in the middle of the middle phalanx.[4]
  • Image at R shows the annular and cruciform pulleys on index finger.

Diagnostic Procedures[edit | edit source]

A fresh pulley injury results in local swelling, tenderness, and pain over the affected area. The main indicator to identify if a total rupture of a pulley has occurred is the appearance of the clinical bowstringing (In this case; when the finger is in flexion, the flexor tendon is taking the shortest line between the top and the base of the finger. Instead of following the phalange). 

Bron 2
This method is very conclusive, but you can only use it with a total rupture of the pulley.[5]
A recent study about the diagnostic procedure of the pulley, was a comparison between the effectiveness of ultrasonography and MRI (Magnetic Resonance Imaging) scanning.
This study showed us that the ultrasonography is a better diagnostic tool than the MRI. Not only because it’s an inexpensive method but also because you can have more precision and a better view with the ultrasonography.[4]

Examination[edit | edit source]

Pulley injuries can be classified according to 3 grades:

  • Grade III: Complete rupture of the pulley causing bowstring of the tendon. Symptoms are: locally pain at the pulley, heard a PO or CRACK, swelling, pain when squeezing or climbing, pain during finger extension
  • Grade II: Partial rupture of the pulley. Symptoms: locally pain at the pulley, pain while extending the finger and while climbing
  • Grade I: Sprain in the finger ligament. Symptoms: Locally pain, pain when squeezing or climbing

Medical Management[edit | edit source]

The tension of the grafts was evaluated to have an idea of the tension that is recommended in a new graft. The tension of a healthy pulley is between 0,49N and 1,69N.
On the bases of those findings, it is recommended that reconstructed pulley be tensioned to approximately 1N[6].

Free extrasynovial tendon grafts are the most common method currently in use for pulley reconstruction. The A2 and A4 are recommended to be reconstructed using multiple loops of free extrasynovial tendon grafts in the same place where the original digital pulley was[7]. The strength of the repaired pulley is correlated with the number of loops in the tendon[8]. However, recent studies suggest that intersynovial donor tendons may be more efficient as free extrasynovial tendon graft[9]. The intersynovial grafts had less frictions, what gives a better mobility in the digits.

Another method reports on the use of the dorsal wrist retinaculum for the reconstruction of the annular digital pulleys[10]. About 8 cm. of the retinaculum is necessary for the reconstruction of each digital pulley. It is recommended that the undersurface of the extensor retinaculum is orientated toward the tendon for better gliding. An independent biomechanical assessment of this pulley reconstruction concluded that this method gives a limitation in mechanical effectiveness. The ever-present Rim, is a tendon weave technique that is based on the remnant of the ruptured pulley. The advantage of this technique is that the long pulley structure retains the flexor tendon in close proximity to the bone. It is a very efficient technique but has also been shown to be one of the weakest pulley reconstruction methods[11].

Physical Therapy Management[edit | edit source]

Rohrbough indicates that there remains some disagreement between researchers as to the treatment of pulley tears.[12]. Stretching is recognized as an important promoter of the formation of strong compacted scar tissue[13]. Stretching involves pulling the finger in the varus direction, effectively hyperextending the metacarpophalangeal joint and PIP joint[14]. An alternative therapy such a squeezing a ball may be useful. Such therapy is useful in promoting healing in the injury, it does not prevent atrophy of other healthy tissues.

Minor A2 pulley injuries or partial tears with no evidence of bowstringing can be treated with either firm circumferential taping for 2 to 3 months to permit healing[15]. The effectiveness of pulley taping was tested and the effect was maximized (10% of bowstringing force) when the tape is positioned near the distal end of the proximal phalanx. The tape absorbed progressively less bowstringing force as the force produced at the fingertip increased[16]; non-stretch, zinc oxide tape of 1.3 cm width was used[15]. This result has two implications. Firstly, taping is likely to be most effective during the earlier stages of rehabilitation when the forces produced by the fingers are lower. Secondly, taping is unlikely to prevent pulley injuries, as these are likely to occur when forces on the pulley are maximal[5].

Key Research[edit | edit source]

  • Digital Flexor Sheath: Repair and Reconstruction of the Annular Pulleys and Membranous Sheath
  • Analysis of the gliding pattern of the canine flexor digitorum profundus tendon through the A2 pulley, Shigeharu Uchiyama1, Peter C. Amadio, Lawrence J. Berglund, Kai-Nan An􏰀 Biomechanics Laboratory, Division of Orthopedic Research, Mayo Clinic, 200 First Street S.W., Rochester, MN 55905, USA Accepted 15 January 2008
  • Zone II Combined Flexor Digitorum Superficialis and Flexor Digitorum Profundus Repair Distal to the A2 Pulley Jeffrey M. Pike, MD, Richard H. Gelberman, MD

Resources[edit | edit source]

Bron 1: http://www.orthobullets.com/hand/6004/flexor-pulley-system
Bron 2: http://edgar.brand.edgar-online.com/EFX_dll/EDGARpro.dll?FetchFilingHTML1?ID=5479903&SessionID=cg7xWq-zAf69x47

References[edit | edit source]

 

  1. ↑ Kaplan EB. Functional and Surgical Anatomy of the Hand. Philadelphia, JB Lippincott Co, 2nd Ed, 1965
  2. ↑ Bone spine Pulley system of hand Available from:https://boneandspine.com/flexor-tendon-pulley-system-of-hand/ (last accessed 17.3.2020)
  3. ↑ Lin GT, Amadic PC, An KN, et al. Functional anatomy of the human digital flexor pulley system. J Hand Surg Am 14:949-956, 1989
  4. ↑ 4.0 4.1 Martinoli, C., Bianchi, S., Nebolio, M., Derchi, L. E., Garcia, J. F. (2000) Sonographic evaluation of digital annular pulley tears. Skeletal Radiol. 29. 387-391 
  5. ↑ 5.0 5.1 Warme, W. J., Brooks, D. (2000) The Effect of circumferential taping on flexor tendon pulley failure in rock climbers. Am. J. Sports Med. 28(5): 674-678
  6. ↑ Seiler JG, Uchiyama S, Ellis F, et al. Reconstruction of the flexor pulley. the effect of tension and source of the graft in an in vitro dog model. J Bone Joint Surg Am 80:699-703, 1998 
  7. ↑ Bunnell S. Repair of tendons in the fingers and descriptions of two new instruments. Surg Gynecol Obstet 26:103-110, 1918 
  8. ↑ Widstrom CJ, Doyle JR, Johnson G. A mechanical study of the effectiveness of 6 digital pulley reconstruction techniques. Part 2. Strength of individual reconstructions. J Hand Surg Am 4:826-829,1989
  9. ↑ Nishida J, Amadio PC, Bettinger PC, et al. Excursion properties of tendon graft sources. interaction between tendon and A2 pulley. J Hand Surg Am 23:274-278, 1998 
  10. ↑ Lister GD. Reconstruction of pulleys employing extensor retinaculum. J Hand Surg Am 4:461-464, 1979 
  11. ↑ Kleinert HE, Bennett JB. Digital pulley reconstruction employing the always present rim of the other previous pulley. J Hand Surg Am 3:297-298, 1978 
  12. ↑ Rohrbough, J. T., Mudge, M. K., Schilling, R. C. (2000) Overuse injuries in the elite rock climber. Med. Sci Sports Exerc. 32(8): 1369-1372 
  13. ↑ R. S., Raya, M. A. (2001) Manual Modalities. in: Gonzalez, E. G., Myers, S. J., Edelstein, J. E., Lieberman, J. S., Downey, J. A. Physiological basis of rehabilitation medicine. 3rd ed. Butterworth Heinemann 
  14. ↑ Gresham, N. (1996) High performance: warming up. High. 166: 14-15 
  15. ↑ 15.0 15.1 Hand Injuries in Rock Climbing. Reaching the Right Treatment Peter J. L. Jebson, MD; Curtis M. Steyers, MD The Physician and Sportsmedicine – Vol 25: No5, May 1997 
  16. ↑ Schweizer, A. (2000) Biomechanical effectiveness of taping the A2 pulley in rock climbers. J. Hand Surg. 25B. 102-107 


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