Zone 1 Flexor Tendon Injuries - Post test


1. Two weeks earlier, an 18 year-old football lineman injured his ring finger with a deformity seen in Figure 1. There is palmar tenderness at the PIP joint and decreased PIP range of motion. What is the most effective treatment for this problem at this time? 

A. Allow the athlete to compete until season’s end and then reconstruct the deformity 
B. Resection of the tendon in the palm
C. Free graft from the palm to the distal phalanx 
D. DIP fusion at 25 degrees of flexion
E. Primary repair of the avulsed tendon 



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Discussion:  This is a Type II FDP avulsion. The profundus tendon is held at the level of the PIP joint by the intact long vinculum. This vinculum perfuses the tendon and allows it to remain in the sheath, thereby getting nutrition through diffusion. 
Reinsertion can occur at a later date because nutrition to the tendon is persistent, but allowing the athlete to continue to compete may convert a Type II injury to a Type I injury if the vinculum is ruptured. This would possibly prevent the ability to preform a primary repair. The best treatment at this time for the finger would be primary repair. 

References: 
1. Leddy JP. Avulsions of the flexor digitorum profundus. Hand Clinics 1985; 77-83. 
2. Leddy JP. Closed flexor tendon disruption in athletes. Hand Clinics 2000; 359-365. 

2. A college student presents 4 weeks after sustaining an injury to the ring finger of the dominant hand while playing flag football. Ultrasound assessment of the digit reveals that the distal stump of the flexor tendon is located at the level of the PIP joint. Inspection of the DIP joint demonstrates mild hyperextension. The recommended treatment is:

A. DIP joint arthrodesis
B. Direct repair of the flexor digitorum profundus
C. Single stage tendon graft reconstruction
D. Two stage flexor tendon reconstruction
E. Non-operative management

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Discussion:  With Type II FDP avulsions (retraction at the level of PIPJ – Figure 1), direct repair (Figure 2) is usually possible up to 6 weeks post-injury. In Type I injuries (more proximal retraction into the palm), reconstructive options may be required if diagnosis is delayed.

References:
1. Leddy JP, Packer JW. Avulsion of the profundus insertion in athletes. J Hand Surg 1977; 2A:66-68.
2. Stamos BD, Leddy JP. Closed flexor tendon disruption in athletes. Hand Clin 2000; 16:359-365.

3.A 17 year-old male football player presents with a swollen, tender ring  finger and inability to flex the distal interphalangeal joint (DIP) joint of his dominant hand. The injury occurred from a missed tackle 5 weeks earlier. Physical examination reveals tenderness over the middle phalanx. He can actively flex the PIP joint without pain. Radiographs are normal. Appropriate management of the injury is:

A.Reinsertion of the avulsed FDP tendon into the distal phalanx
B.Primary tendon grafting and pulley reconstruction
C.Two-stage FDP tendon reconstruction with silicone rod insertion and delayed grafting
D.Conversion to a one-tendon finger
E.Fusion of the DIP joint in slight flexion

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Discussion:  Avulsion of the FDP tendon from the distal phalanx most often involves the ring finger in athletes. Leddy and Packer described 3 types of injuries: Type I involves retraction of the tendon into the palm; Type II involves retraction to the level of the PIP joint; Type III involves little or no proximal retraction. Type I injuries, with an empty digital flexor sheath, require early exploration and repair, generally within 10 days to prevent shortening and scarring of the proximal musculotendinous unit. Radiographs may or may not show associated avulsion fractures. McCallister, et al. showed that radiographic findings may be misleading, and they recommended early exploration and repair within 10 days for all FDP avulsions. True Type III injuries (Figure 1) can be successfully repaired for up to six weeks after injury. Primary or secondary tendon grafting is useful in delayed treatment of longstanding avulsion injuries with proximal contraction and scarring of the musculotendinous unit. Fusion of the DIP joint is an option when no useful proximal motor remains and the DIP joint hyperextends.

References:
1. Leddy JP, Packer JW. Avulsion of the profundus tendon insertion in athletes. J Hand Surg 1977;2:66-69.
2. McCallister WV, Ambrose HC, Katolik LI, Trumble TE. Comparison of pullout button versus suture anchor for zone I  flexor tendon repair. J Hand Surg 2006;31A:246-251.

4. A 43 year-old attorney presents with the following injury two days after trying to restrain his dog by grabbing the dog’s collar. What type of zone 1 flexor digitorum profundus avulsion is this?

A. Type I
B. Type II
C. Type III
D. Type IV
E. Type V

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Discussion:  The classification of Leddy and Packer initially divided  flexor digitorum profundus injuries into three categories, which has since been modified.
-Type I injuries are pure avulsions, including both the long and short vincula, which allows the tendon end to retract to the palm. It must be retrieved and repaired within 10 days before the tendon degenerates and myostatic contracture occurs.  
-
Type II injuries have an intact long vinculum which tethers the tendon’s distal end at the PIP joint. Because the motor unit has not shortened dramatically, repairs are possible up to several weeks, or even months after the injury.
-Type III injuries include a bony avulsion fragment which prevents the tendon from retracting, usually at the level of the A4 pulley. This can be repaired in a timeframe similar to Type II.
-Type IV injuries occur when the distal tendon stump becomes detached from the avulsed fragment, and can retract proximally. The stump may be invisible on x-ray. If it is retracted into the palm, the time to repair is like the type I and there needs more rapid intervention. Authors emphasize the deceptive nature of these injuries. Ultrasound or MRI may be useful to determine the level of the distal tendon end and help guide treatment.
-Type V injuries include both an avulsed osseous fragment, which may be limited in retraction by the pulley system, as in the above example and a concomitant distal phalanx fracture. Authors emphasize the challenging nature of these rare injuries, including comminution and joint incongruity, or subluxation of the DIP joint.


References:
4. Qattan MM. Type 5 avulsion of the insertion of the flexor digitorum profundus tendon. J Hand Surg 2001;26B 5:427-31.
5. Chen C, Li TS, Liu YT, Chen HC. Miniplate hooking method for repair of type III flexor digitorum profundus avulsion injury with a small bone fragment: case report. J Hand Surg 2009;34A:1449-53.
6. Trumble TE, Vedder NB, Benirschke SK. Misleading fractures after profundus tendon avulsion: a report of six cases. J Hand Surg 1992;17A:902-7.
7. Henry SL, Katz MA, Green DP. Type IV avulsion: Lessons learned clinically and through review of the literature. Hand 2009;4:357-61.

5. An 18yo female trips on the steps and catches the hand rail with only the small fingertip. She presents to your clinic the next day with the swollen, painful finger seen in Figures 1 and 2. The most appropriate treatment is: 

A. Splint and rehabilitation.
B. Open reduction, internal fixation within 6 weeks.
C. Open reduction, internal fixation and tendon repair within 6 weeks.
D. Tendon repair within 2 weeks.
E. Open reduction, internal fixation and tendon repair within 4-7 days.

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Discussion:  Leddy and Packer classified FDP avulsion into 3 types. In type 1 the FDP retracts into the palm and must be repaired within several days optimally to prevent myostatic contraction and flexor sheath noncompliance. In type II avulsions, the FDP is held at the PIP joint level by the vinculum longum profundus and may be repaired as late as 6 weeks. In type III avulsion, the FDP is avulsed with a large fragment of joint attach which holds it at the distal end of the A4 pulley thus allowing delayed repair. However type III avulsions, as seen in this patient, can be deceptive pre-operatively both clinically and radiographically. Occasionally the FDP stump itself is avulsed from the bony fragment (a so called type IV injury) and the stump may be found either in the palm or in the tendon sheath. Early exploration is indicated. 

References: 
1. Green, David P. Operative Hand Surgery, 5th Ed.Vol. 1. Philadelphia, PA: Elsevier, 2005: 226-229. 
2. Leddy JP. Avulsions of the flexor digitorum profundus. Hand Clin. 1985;1:77-83.
3. Leddy JP, Packer JW. Avulsion of the profundus tendon insertion in athletes. J Hand Surg [Am] 1977;2:66-69.
4. Eglseder WA, Russell JM. Type IV flexor digitorum profundus avulsion. J Hand Surg 1990;15:735-739.
  

6. In flexor profundus injuries retracted to the level of the proximal interphalangeal (PIP), tendon vascularity is maintained by which of the following structures?

A. Vinculum longus profundus
B. Vinculum brevis profundus
C. Intraosseous vessels from distal phalanx
D. Extraosseous vessels from distal phalanx
E. Vascular leash from the A5 pulley

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Discussion:  Leddy and Packer described a classification system for profundus injuries based upon the level of retraction of the avulsed tendon. Disruption of both viculum longus and brevis takes place when the avulsed tendon retracts into the palm. The vinculum longus profundus blood supply arises at the level of the volar plate of the PIP joint. When the avulsed profundus does not retract proximal to the proximal interphalangeal joint, vascularity to the profundus is preserved by the vinculum longus profundus. The vinculum brevis vascularizes the profundus at the level distal to the A5 pulley. Retraction of the tendon to the level of the PIP joint therefore results in disruption of the vinculum brevis. Distally, blood supply to the tendon is both intraosseous from the distal phalanx and an extraosseous (vinculum brevis).

References:
1. Leversedge FJ, Ditsios K, Goldfarb CA, Silva MJ, Gelberman RH, Boyer MI. Vascular anatomy of the human flexor digitorum profundus tendon insertion. J Hand Surg Am. 2002;27(5):806-812.
2. Leddy JP, Packer JW. Avulsion of the profundustendon insertion in athletes. J Hand Surg Am. 1977;2(1):66-69.

7.Which of the following is the most common reason for the infrequent use of intrasynovial tendon graft in hand tendon reconstruction as compared to extrasynovial tendon graft?

A. Increased tendon adhesions
B. Healing with lack of gliding surface
C. Poor early functional result
D. Poor late functional result
E. Limited availability

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Discussion:  In various studies intrasynovial tendon grafts have been found to heal with less adhesion and with better functional results. Histologically intrasynovial tendons have a single layer lining of epitenon cells and as tendon grafts they heal with preservation of gliding surface and resemble the cellular properties of the damaged zone II flexor tendon. Despite overall better outcomes from animal studies, intrasynovial tendon grafting is not routinely used because donor intrasynovial tendons are limited to the flexor digitorum longus tendons of the foot.

References:  
1. Chang J. Studies in flexor tendon reconstruction: biomolecular modulation of tendon repair and tissue engineering. J Hand Surg Am. 2012;37(3):552-561.
2. Leversedge FJ, Zelouf D, Williams C, Gelberman RH, Seiler JG 3rd. Flexor tendon grafting to the hand: an assessment of the intrasynovial donor tendon-A preliminary single-cohort study. J Hand Surg Am. 2000; 25(4):721-30.
3. Gelberman RH, Seiler JG 3rd, Rosenberg AE, Heyman P, Amiel D. Intercalary flexor tendon grafts. A morphological study of intrasynovial and extrasynovial donor tendons. Scand J Plast Reconstr Surg. 1992; 26(3):257-264.

8. A laceration of a ring finger flexor digitorum profundus tendon occurs distal to the insertion of the superficialis tendon. Primary repair was achieved, but required debridement of 1.5 cm of the damaged tendon ends. Four months later, the most likely clinical consequence is:

A. Bowstringing of the tendon in the ring finger.
B. Inability to fully flex the ring finger.
C. Inability to fully flex the long finger.
D. Boutonniere deformity of the adjacent long and small fingers.
E. Paradoxical extension of the long and small fingers.

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Discussion:  The quadriga phenomenon occurs as a result of over shortening of a profundus tendon. Because the flexor digitorum profundus tendons of the fingers are connected, excessive shortening of one will limit the ability of the other fingers to flex fully. However, the finger with the repaired tendon will flex fully, effectively 'bottoming out' as the other fingers will not have enough excursion to flex actively, through their passive range of motion. Bowstringing occurs as a result of pulley insufficiency. Boutonniere deformity is a result of intrinsic imbalance and paradoxical extension occurs as a result of a lumbrical contracture. Typically debriding more than 1 cm can result in quadriga.

References:
1. Lilly, SI, and Messer TM. Complications After Treatment of Flexor Tendon Injuries. J. Am. Acad. Orthop. Surg. 2006;387-396.
2. Strickland, JW. Development of Flexor Tendon Surgery: Twenty-Five Years of Progress. J Hand Surg. Am. 2000;214-235.
3. Momeni A, Grauel E, Chang J. Complications after flexor tendon injuries. Hand Clin. 2010;26(2):179-189.

9. Outcome studies comparing flexor tendon rehabilitation protocols reveal:

A. Better results with passive motion protocols
B. Better results with six weeks of immobilization
C. Decreased rupture rates with place and hold techniques
D. Improved results with use of a certified hand therapist
E. Superior total active motion with a home exercise program only

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Discussion:  Two primary rehabilitation protocols are currently being used. Klienert type with passive flexion and active extension, and place and hold protocols with active and passive flexion. The place and hold protocol utilizes passive flexion with some type of active flexion. Several studies have evaluated the outcomes of these 2 protocols and have found that the outcomes are roughly the same with similar motion, strength and rupture rates. In most studies, however, the presence of a certified hand therapist supervising improved overall function and patient satisfaction.

References:
1. Matarrese MR, Hammert WC. Flexor tendon Rehabilitation. J Hand Surg. 2012;37A:2386-2388.
2. Chesney A, Chauhan A, Kattan A, Farrokyar F, Thomas A. Systemic review of flexor tendon rehabilitation protocols in Zone II of the hand. Plast Reconstr Surg. 2011;127:1583-1592.

10. A patient sustains a traumatic, ring finger flexor digitorum profundus tendon rupture (jersey finger) diagnosed by physical examination and confirmed by MRI. He elects no surgical treatment initially. Three months later, he notes that when he attempts to flex the finger, it involuntarily extends at the proximal interphalangeal joint. The most likely cause of this phenomenon is:

A. Change in distal insertion of the profundus tendon
B. An extrinsic extensor tendon contracture
C. An intrinsic contracture of the third palmar interosseous muscle
D. A pseudoboutonniere deformity
E. A swan neck deformity

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Discussion:  Paradoxical digital extension most commonly occurs after finger amputation when the flexor digitorum profundus tendon is divided and retracts proximally. It may also occur in poorly balanced flexor tendon reconstructions. When the distal insertion of the profundus ruptures all flexion power of the distal interphalangeal joint is lost. However, with the profundus tendon insertion now becomes the lumbrical. Subsequently, when attempting active flexion of the finger, the lumbrical pulls the proximal and distal interphalangeal joints paradoxically into extension (and the metacarpal-phalangeal joint into flexion) through its’ attachment to the radial lateral band. If indicated clinically, treatment may include operative division of the lumbrical tendon.

References:
1. Tosti R, et.al. Intrinsic Contracture of the Hand: Diagnosis and Management. J Am Acad Orthop Surg. 2013; 21: 581-591.
2. Lilly SI, Messer TM: Complications after Treatment of Flexor Tendon Injuries. J Am Acad Orthop Surg. 2006; 14: 387-396.                               

11. A patient presents with loss of grip one year following repair of a zone I flexor tendon laceration. With active digital flexion, the distal and proximal interphalangeal joints extend. Which of the following procedures is most likely to address this issue?

A. Terminal extensor tendon tenotomy
B. Oblique retinacular ligament reconstruction
C. Distal instrinsic release
D. Lumbrical release
E. Ring FDS transfer

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Discussion:  The patient in the question has a lumbrical plus finger. This is characterized by paradoxical extension of the PIP and DIP joints with active flexion of the digit. The ring finger is most commonly involved in the case of jersey finger (distal FDP avulsion). Causes include a rupture of a previously repaired FDP tendon or a repaired FDP tendon that is “too long” (i.e. gapped) and not able to generated enough force. The lumbrical muscle originates from the FDP tendon and acts through the lateral bands to extend the IP joints and flex the MP joints. When the proximal end of the ruptured repair retracts within the tendon sheath, the lumbrical retracts with it, thus putting an increased force of MP flexion and IP extension on the affected finger. Appropriate treatment is lumbrical release. Distal intrinsic release does not address the pathology directly but is used for an intrinsic contracture. FDS tenotomy would not address the pathology here and is contraindicated in the setting of an absent FDP in that finger.

References: 
1. Lilly SI, Messer TM. Complications After Treatment of Flexor Tendon Injuries. J Am Acad Orthop Surg. 2006;14(7):387-396.
2. Parkes A. The “lumbrical plus” finger. J Bone Joint Surg Br. 1971;53(2):236-239.

12. In a two-stage flexor tendon reconstruction using the Paneva-Holevich technique (which creates an FDS pedicle graft where in the first stage, the FDS and FPD proximal ends are looped and sutured together in the palm), the main disadvantage is:

A. The tendon graft is extrasynovial
B. Tensioning of the graft is done at the distal end
C. A lumbrical plus finger commonly results
D. Rupture at the proximal end of the graft
E. The graft diameter may not match the diameter of the silicone rod

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Discussion:  Flexor tendon reconstruction using a tendon graft can be performed as a one-stage or two-stage procedure. Adequate passive motion, a well-healed wound and satisfactory vascular status are required for either reconstruction. In addition, a patient must be cooperative during the complex rehabilitation process. If pulley reconstruction, nerve repair, joint capsule release or abundant scar tissue is present, this should be addressed at the first stage of a planned procedure, along with silastic rod placement.

Intrasynovial tendon grafts, such as the FDS or toe flexors, may have a theoretical advantage over extrasynovial tendon grafts (palmaris longus, plantaris or toe extensors) but may produce more donor site morbidity or be more difficult to obtain.

The technique of creating a loop in the palm between the proximal stump of the FDS and FDP tendons (the technique of Paneva-Holevich and others) while the sheath is prepared and silastic rod placed has some advantages. The main disadvantage is that the tensioning of the graft must be done at the distal end of a flexed digit, since the proximal end has healed to the profundus.

At the second stage, the FDS tendon is released in the forearm at its proximal end, is reversed as a "pedicled flap," and passed distally from the forearm through the palm and the created pseudosheath, with the proximal junction now healed. Thus, rupture is less likely at the proximal junction. Distally, the FDS is then attached to the distal phalanx, but it is more difficult to adjust the tendon tension at the distal phalanx than it would be if the site of connection were made in the palm or forearm (i.e. with a weave). The FDS tendon is intrasynovial.

The silastic rod has been chosen at stage one to best match the diameter of the tendon, so graft diameter mismatch is not likely to be an issue. Lumbrical plus fingers are not common with staged grafting.
 
References:
1. Freilich AM, Chhabra AB. Secondary flexor tendon reconstruction, a review. J Hand Surg Am. 2007;32(9):1436-1442.
2. Goldfarb CA, Gelberman RH, Boyer MI. Flexor Tendon Reconstruction: Current Concepts and Techniques. J Hand Surg Am. 2005;5(2):123-130.
3. Beris AE, Darlis NA, Korompilias AV, Vekris MD, Mitsionis GI, Soucacos PN. Two-stage flexor tendon reconstruction in zone II using a silicone rod and a pedicled intrasynovial graft. J Hand Surg Am. 2003;28(4):652-660.
4. Abrams RA. Flexor tendon reconstruction in zone 1 and 2. In: Weiss APC, Goldfarb CA, Hentz VR, Raven RB, Slutsky DJ, Steinmann SP, eds. The American Society for Surgery of the Hand Textbook of Hand & Upper Extremity Surgery. Chicago, IL: American Society for Surgery of the Hand; 2013:437-456.

13. Which of the following donor tendons used for flexor tendon reconstruction has been reported by basic science investigators to show better survival without peritendinous adhesions when transplanted to the digital synovial sheath?

A. Palmaris Longus
B. Plantaris
C. Extensor Digitorum Longus (2nd toe)
D. Flexor Digitorum Longus (2nd Toe)
E. Extensor Indicis Proprius

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Discussion:  Options for the donor tendon used in tendon reconstruction include the palmaris longus, plantaris, extensor digitorum longus (2nd, 3rd and 4th toe), extensor indicis proprius, extensor digiti quinti and flexor digitorum longus (2nd-5th toe). Of these, the palmaris longus and plantaris are the most commonly used but are available and usable as grafts in 75% and 50%, respectively.
Intrasynovial donor tendons like the toe flexor digitorum longus have been shown in basic science investigations to survive transplantation to the digital sheath and heal with less peritendinous adhesions than extrasynovial donor tendons. The long flexors of the second to fifth toe can be sacrificed with minimal morbidity, and their clinical application has been demonstrated in a small, single cohort study. Clinical advantages of intrasynovial grafts, therefore, remain in question.

The toe flexor's length is generally not sufficient to transport only one intrasynovial tendon to the site of reconstruction, but multiple palm-to-fingertip grafts can be harvested.

The Paneva-Holevich procedure using a FDS/FDP loop represents another opportunity to use an intrasynovial tendon graft.

References:
1. Seiler JG 3rd, Reddy AS, Simpson LE, Williams CS, Hewan-Lowe K, Gelberman RH. The Flexor Digitorum Longus: An Anatomic and Microscopic Study for Use as a Tendon Graft. J Hand Surg Am. 1995;20(3):492-495.
2. Noguchi M, Seiler JG 3rd, Boardman ND, Tramaglini DM, Gelberman RH, Woo SL. Tensile Properties of Canine Intrasynovial and Extrasynovial Flexor Tendon Autografts. J Hand Surg Am. 1997;22(3):457-463.
3. Leversedge FJ, Zelouf D, Williams C, Gelberman RH, Seiler JG 3rd. Flexor Tendon Grafting to the Hand: An Assessment of the Intrasynovial Donor Tendon-A Preliminary Single-Cohort Study. J Hand Surg Am. 2000;25(4):721-730.
4. Nishida J, Amadio PC, Bettinger PC. Flexor Tendon-Tendon Shealth Interaction After Tendon Grafting:A Biomechanical Study in a Human Model In Vitro. J Hand Surg Am. 1999;24(5):1097-1102.
5. Nishida J, Amadio PC, Bettinger PC. Excursion Properties of Tendon Graft Sources: Interaction Between Tendon and A2 Pulley. J Hand Surg Am. 1998;23(2):274-278.