EXTENSOR TENDON LACERATION

Introduction

Tendon lacerations are some of the most common injuries seen by hand surgeons, with extensor tendons being involved slightly more often than flexor tendons. Extensor tendon lacerations typically result from penetrating trauma to the dorsal surface of the forearm, wrist, palm, or digits that reaches the extensor tendon(s). Falling into a mirror or window are common mcchanisms of injury that cause extensor tendon laceration. Depending on the location of tendon involvement, the patient may be unable to extend the affected digit(s) or thumb, thus causing a severe impairment to hand function.

Extensor tendon lacerations typically receive less attention than their flexor tendon counterparts, even though their incidence is higher and anatomy more complex, with management being more varied depending on the anatomical zone of injury. There is also a misconception that repairing extensor tendons is comparatively easier. It can, however, be quite difficult because of the tendon’s smaller size and lack of collagen-bundle linkage, which reduces the grip strength available for the suture material. Due to the nuances of managing these injuries, it is essential for surgeons to have a complete understanding of the decision-making process and to conduct an appropriate workup before deciding on the optimal treatment course to increase the chances of a positive outcome.^1-4

Pathophysiology

An extensor tendon laceration occurs when a traumatic injury to the dorsal side of the palm, fingers, or thumb penetrates through the skin deep enough to lacerate the underlying extensor tendon(s).^1,5,6
The penetrating trauma can be accidental or intentional, and often involves sharp metal or broken glass. Windows, mirrors, knives, and saws are all commonly involved in injuries that result in extensor tendon lacerations.^1,5,6

Related Anatomy^1,2

The extensor tendon system of the wrist, hand, and fingers is more complex than the flexor tendon system. The 6 extensor compartments of the wrist and intrinsic muscles of the hand comprise 23 musculotendinous units.¹
Extension is accomplished through the coordinated efforts of an intricate and interconnected system of extensor muscles, their terminal tendons and the median and ulnar innervated intrinsic muscles. The muscles comprising the extrinsic extensor tendon complex are located in the dorsal aspect of the forearm and all are innervated by the radial nerve.²
- Extensor retinaculum
  - A dense, thickened, fibrous fascia that holds the tendon sheaths down and prevents bowstringing during muscle contraction and finger and thumb extension.
- Extensor expansion
  - Fibrous fascia stretching from the metacarpophalangeal (MP) joint to halfway down the proximal phalanx that holds the extensor tendon down and in a central position.
- Extensor pollicis brevis (EPB)
  - Extends the thumb at the MP joint
- Extensor pollicis longus (EPL)
  - Extends the thumb at the interphalangeal (IP) joint
- Extensor indicis proprius
  - Extends the index finger
- Extensor digiti minimi
  - Extends the little finger
- Extensor digitorum communis
  - Involved in extension of index, long, ring and little finger
  - Juncturae tendinum - a tendinous interconnection between the extensors of long, ring and little fingers.
The extensor tendon system can be divided into 8 anatomic zones (Verdan’s zones), and extensor tendon lacerations are typically classified based on their location in one of these zones:
- Zone I: over the distal interphalangeal (DIP) joint
  - Common injuries that are usually closed and result from any activity that forcefully flexes the tip of a digit, but open injuries resulting from penetrating trauma are also possible; associated with mallet finger deformity
- Zone II: between the DIP and proximal interphalangeal (PIP) joints
  - Typically occur from lacerations, and are more likely to be partial with some intact tendon and therefore some active extension; seen less frequently than zone I injuries and also associated with mallet finger
- Zone III: over the PIP joint
  - Can occur in both open and closed manners, with open injuries involving disruption of the central slip; associated with the boutonniere deformity
- Zone IV: between the PIP and MP joints
  - Similar to zone II injuries, but the anatomy is more complex; most injuries in this region are open, and partial lacerations are the norm. The extrinsic and intrinsic extensor tendons combined in this zone because of the connections between the lateral bands and the extensor tendon
- Zone V: over the MP joint
  - Typically open injuries, with a high prevalence occurring from human teeth (ie, “fight bites”)
- Zone VI: between MP and wrist joints
  - Not very common, but often associated with significant trauma and concomitant injuries
- Zone VII: over the wrist joints
  - Open injuries occur under the retinaculum and are often complicated by adhesion and loss of motion
- Zone VIII: proximal to the wrist joints
  - Associated with significant tendon retraction⁴ with damage to muscle bellies and/or tendon.

Overall Incidence

One study found that zone III was the most commonly injured anatomical region (12.6%), and that the extensor mechanism in the index finger was injured significantly more often than any other tendon (15.6%).⁶
Another study presented slightly different figures, with the long finger being most commonly injured, but zones V and IIIT (of the thumb) were the regions with the highest incidence.³A separate trial also found zones V (36%) and III (34.7%) to be the most common locations of lacerations, and zones I and IV to be the least common sites of injury.⁷
Hand injuries have been found to account for 14-30% of all injuries treated in the ED. Of these, ~42% are fractures and ~29% are tendon injuries.⁸
Extensor tendon lacerations are more common than flexor tendon lacerations, with one study of 124 tendon lacerations finding that 61.3% involved the extensor tendons. The only area in which incidence rates were similar was the fingers, which may be explained by the more superficial location and lack of protection of the extensor tendons on the dorsum of the hand.
- This study also found that 54.8% of patients with a small laceration experienced a concomitant tendon injury, and 92.5% of patients with a deep injury through a small laceration experienced concomitant tendon injury.⁹
- Another 10-year study of 458 acute traumatic tendon injuries of the hand and wrist involved 692 tendons, and 184 (26.6%) of these were reported to be partially lacerated.
  - This study also found a higher incidence of extensor tendon injuries (n=395) than flexor tendon injuries (n=297).⁶
  - Work-related accidents have been found to account for ~25% of extensor tendon injuries.⁵
- The average age of patients who sustain extensor tendon injuries is 35 years, and the male-to-female ratio has been found to range from 3:1 to 6:1.⁵

Related Injuries

Metacarpal fracture
Phalangeal fracture
Mallet finger
Nerve laceration
Vascular laceration

ICD-10 Codes

Diagnostic Guide Name

EXTENSOR TENDON LACERATION

ICD 10 Diagnosis, Single Code, Left Code, Right Code and Bilateral Code

DIAGNOSIS	SINGLE CODE ONLY	LEFT	RIGHT	BILATERAL (If Available)
EXTENSOR TENDON LACERATION (FOREARM LEVEL)
- INDEX		S56.422_	S56.421_
- MIDDLE		S56.424_	S56.423_
- RING		S56.426_	S56.425_
- LITTLE		S56.428_	S56.427_
- THUMB		S56.322_	S56.321_
EXTENSOR TENDON LACERATION (WRIST AND HAND LEVEL)
- INDEX		S66.321_	S66.320_
- MIDDLE		S66.323_	S66.322_
- RING		S66.325_	S66.324_
- LITTLE		S66.327_	S66.326_
- THUMB		S66.222_	S66.221_

Instructions (ICD 10 CM 2020, U.S. Version)

THE APPROPRIATE SEVENTH CHARACTER IS TO BE ADDED TO EACH CODE FROM CATEGORY S56 AND S66

A - Initial Encounter

D - Subsequent Routine Healing

S - Sequela

ICD-10 Reference

Reproduced from the International statistical classification of diseases and related health problems, 10th revision, Fifth edition, 2016. Geneva, World Health Organization, 2016 https://apps.who.int/iris/handle/10665/246208

Clinical Presentation Photos and Related Diagrams

Extensor Tendon Lacerations

Middle aged carpenter with a power saw injury to the right thumb. Irrigated, debrided, temporarily closed & placed on IV antibiotics prior to definitive repairs.
Right handed 28 y.o. male with multiple lacerations secondary a shattered glass door. Noted extension lag in the right thumb.

Basic Science Photos and Related Diagrams

Suture Techniques for Extensor Tendon Repair

Basic Science Pics

A Doyle style modified Kessler style core suture for extensor tendon repair around the dorsal PIP joint area. A 3-O or 4-O braided synthetic permanent suture is one acceptable suture choice for the the core suture which is place in the extensor tendon proximally and in the central slip (arrow) distally.
A horizontal mattress suture or one where the longitudinal part of the suture passes under instead of through the tendon can sometimes be helpful in finger extensor repairs. A 3-O or 4-O braided synthetic permanent suture is one acceptable suture choice for the the core suture.
A modified Kessler or Tajima style (insert) core suture can also be used for the extensors where they are thicker over the dorsal of the hand or wrist. A 3-O or 4-O braided synthetic permanent suture is one acceptable suture choice for the the core suture.
Simple double right angle core suture for thick extensor tendons. A 3-O or 4-O braided synthetic permanent suture is one acceptable suture choice for the the core suture.
A separate second suture for the edge or epitenon part of the extensor repair is very important. This simple running suture is appropriate suture technique for this repair . A 6-O nylon is one acceptable suture for the epitenon repair.
A separate second suture for the edge or epitenon part of the extensor repair is very important. This simple running locking suture is another appropriate suture technique for this repair . A 6-O nylon is one acceptable suture for the epitenon repair.
A separate second suture for the edge or epitenon part of the extensor repair is very important. This locking Cross-Silferskiold suture is another appropriate suture technique for this repair . A 6-O nylon is one acceptable suture for the epitenon repair.

Pathoanatomy Photos and Related Diagrams

Extensor Tendon Zones and Extensor Compartments

Extensor Tendon Zones of Injury. Zone I to Zone VII for the fingers, hand and wrist. Zones TI to TV for the thumb.
The extensor retinaculum prevents bowstring during extension. Its vertical septa define six extensor compartments. The first contains the Abductor Longus and Extensor Pollicis Brevis; the second contains the Extensor Carpi Radialis Longus & Brevis; The third contains the Extensor Pollicis Longus; The fourth contains the Extensor Digitorum Communis & Extensor Indicis Proprius: The fifth contains the Extensor Digiti Minimi; & the sixth contains the Extensor Carpi Ulnaris.

Extensor Tendons Finger

Dorsal view of finger extensor tendons: A. Extensor tendon; B. Central slip; C. Oblique fibers of the dorsal aponeurosis; D. Lateral slip; E. Conjoined lateral band; F. Triangular ligament; G. Terminal extensor tendon.
Lateral view of finger extensor tendons: A. Extensor tendon; B. Central slip; C. Oblique fibers of dorsal aponeurosis; D. Lateral slip; E. Conjoined lateral band; F. Triangular ligament; G. Terminal extensor tendon; H. Flexor digitorum profundus; I. Volar plate; J. A-2 & A-4 pulleys; K. Flexor digitorum superficialis; L. Transverse retinaculum; M. Accessory collateral ligament; N. Proper collateral ligament

Symptoms

History of penetrating trauma, e.g. laceration, to the digits, hand or wrist

Pain at the site of injury

Impaired finger and/or wrist extension

Typical History

The typical patient is a 36-year-old, right-handed male who injured his hand from a punching injury. The man, who was extremely intoxicated, had been watching his favorite football team play in the Super Bowl. After his team lost a close game that came down to the final stretch, he punched a mirror with his right fist. The impact shattered the mirror and the broken glass cut through his fist at the MP joint, in zone V, lacerating the extensor indicis proprius of the index finger. The wound then began bleeding profusely and was wrapped with a temporary compression bandage. The patient was brought to the emergency room by his friends.

Positive Tests, Exams or Signs

Work-up Options

Images (X-Ray, MRI, etc.)

X-ray of thumb extensor laceration and associated open fracture of the proximal phalanx.

$X-ray AP thumb for thumb extensor laceration and associated open fracture after ORIF of proximal phalanx.$
X-ray AP thumb for thumb extensor laceration and associated open fracture after ORIF of proximal phalanx.
$X-ray Lateral thumb for thumb extensor laceration and associated open fracture after ORIF of proximal phalanx.$
X-ray Lateral thumb for thumb extensor laceration and associated open fracture after ORIF of proximal phalanx.
$Lateral & AP thumb X-ray of open proximal phalanx fracture after several months of healing and remodeling (arrow).$
Lateral & AP thumb X-ray of open proximal phalanx fracture after several months of healing and remodeling (arrow).

Treatment Options

Treatment Goals

The most important factors in determining the optimal treatment course for extensor tendon lacerations are the anatomical zone, chronicity of the injury, and any concomitant injury or pathology.¹
The primary goal of extensor tendon repair is to create a strong, stable repair that promotes intrinsic healing and allows the affected tendon to glide smoothly. Although the strength of the repair is not as important as it is in flexor tendon lacerations, care must still be taken to ensure minimal shortening of the tendon substance to maintain an intricate mechanical balance of the extensor apparatus.^10,11
Surgical tendon repair should minimize gapping at the repair site, prevent the formation of adhesions, minimize extrinsic and intrinsic scarring, utilize easy suture placement with secured knots and smooth end-to-end tendon apposition, and avoid injury to the tendon vasculature^10-12

Conservative

A conservative approach may be used for some partial extensor tendon lacerations, but there is still some debate on this topic, as opinions are divided as to whether or not surgery is still preferable.^1,13
When indicated, a typical conservative treatment protocol for extensor tendon lacerations includes suturing the laceration, wound care, and early ROM exercises.^1,13
For zone II injuries in which only one lateral band is lacerated and 50% or more of the tendon is intact, the injury can be treated with a short course of immobilization. Injuries to the terminal extensor tendon with an apparent extensor lag or loss of DIP joint extension strength should be treated with a longer period of immobilization or with primary repair.¹
Patients with zone IV lacerations that can extend against resistance and without an extensor lag may also be treated conservatively.¹
If there is to be any delay in treatment, the hand should first be immobilized in position of function with the MP joint at 70° flexion and the IP joints at ~10° flexion.²

Operative

Surgical repair is generally regarded as the mainstay of treatment for extensor tendon lacerations, and a variety of surgical options are available; however, there are currently no clinical practice guidelines, quality measures, or a gold standard intervention for extensor tendon repair.^1,2,4,10,12
Substantial tendon involvement is one of the primary indicators for surgical repair, but due to the scarcity of supporting literature, there is no agreement on the amount of involvement that should be used as a cut-off point. Other major indications for end-to-end extensor tendon repair are failure to respond to conservative treatment after six months and a clean-cut extensor tendon injury or tendon injury in a wound that can be converted to a clean-cut wound with limited damage to peritendinous tissues.^1,4,14Absolute contraindications to extensor tendon repair are severe contamination, signs of infection, and long defects of the extensor tendons. Serious crush injuries, severe wound contamination, and extensive destruction supporting structures are also contraindications for repair, while loss of soft tissue coverage over the tendon or the presence of fractures are borderline contraindications. Initial surgical treatment may have to be directed at controlling infection, fixation of fractures and obtaining appropriate soft tissue coverage before the extensor tendons can be safely reconstructed.¹
Primary end-to-end extensor tendon repair is performed immediately after wound cleaning and debridement, usually within several to 24 hours after the inciting trauma.¹
Delayed primary end-to-end repair is performed days to three weeks after trauma, after initial irrigation, debridement, and closure of the wound at the time of injury. Delayed repair needs to be performed within three weeks post-injury, as surgery is not typically possible beyond this timeframe because of proximal tendon swelling and tendon retraction.^1,10Whenever possible, acutely lacerated extensor tendons should be treated primarily or during the delayed primary stage. In an ideal situation, the patient is seen in the outpatient center soon after injury. There, an experienced hand surgeon should re-evaluate the patient, provide appropriate patient education, and make a surgical plan for extensor tendon repair.¹
There are some specific nuances to each anatomic zone that must be considered when deciding on the optimal surgical approach:
Deciding what type of incision to use should be based the orientation of the wound, the preference of the surgeon, and the laceration’s location.¹⁰
Suture technique, suture material, and suture configuration are all essential for achieving optimal strength in tendon repairs. Surgeons must therefore understand the mechanical properties of different types of suture materials and repair techniques to increase the chances of a positive outcome.¹⁵The number of core suture strands that cross the repair site is more important than the number of grasping loops, and current literature has shown that multiple core suture strands (2-4) crossing the repair site result in a stronger repair that can usually tolerate early active ROM rehabilitation protocols. Repair strength can be further increased with higher suture caliber and stiffer suture materials. Adding an epitendinous stitch also improves the biomechanical strength of repairs, minimizes gapping, and helps reduce cross-sectional area, which in turn decreases gliding friction. The epitendinous stitch also increases the repair strength.¹²
Wide-awake extensor tendon repair may also be considered, as it allows for intraoperative assessment of repair gaps, reduces the need for postoperative tenolysis, and facilitates postoperative early active ROM
- Zone I: wound management needs to be considered in open injuries with tendon or skin loss; local advancement flaps can make up for small defects and skin grafts can also be helpful in select situations; free tendon grafts are occasionally needed to reconstruct the extensor mechanism
- Zone II: primary repair is preferred for lacerations that involve >50% of the extensor tendon; options range from technically simple sutures (eg, figure-of-eight or horizontal mattress) to more complex approaches such as the Silfverskiöld or an interlocking horizontal mattress
- Zone III: in the absence of purulence or overt signs of infection, surgical repair of the central slip is indicated, and for injuries without an adequate distal tendon for direct repair, suture anchor repairs may be needed; biomechanically suture anchor repair appears similar to suture repairs
- Zone IV: patients with an extensor lag and/or lack of extension against resistance should undergo surgical exploration and are usually treated with surgical repair; a variety of tendon repair techniques are available
- Zone V: patients with “fight bites” should be aggressively treated with surgical irrigation and debridement of the MP joint, as well as tendon repair, if indicated; common suture techniques include the modified Kessler, modified Bunnell, mattress, and figure-of-eight
- Zone VI:injuries in this zone are more amenable to core suture repair with 3-0 or 4-0 nonabsorbable sutures similar to those for flexor tendon injuries because the extensor is more oval or circular and thicker
- Zone 7: extensor tendons in this zone are repaired with a strong, nonabsorbable core suture; if the tendon repair is located in the area of the extensor retinaculum, a small section can be resected or a lengthening of the retinaculum can be performed to prevent bowstringing
- Zone 8: if there are multiple injuries, all divided structures should be repaired, and nerve repairs should be performed simultaneously with tendon repair(s); if the injury precludes direct repair of all structures, repair to allow independent wrist and thumb extension is most important¹

Treatment Photos and Diagrams

Extensor tendon Surgery

$ORIF of fracture with K-wire completed. Core sutures have been placed and 6-O nylon epitendinous suture being placed.$
ORIF of fracture with K-wire completed. Core sutures have been placed and 6-O nylon epitendinous suture being placed.
EPL and EPB lacerations secondary to broken glass door injury. Note distal stump of the EPL (arrow). Proximal laceration was superficial with no injury to deeper structures.
Thumb laceration with proximal EPL (1) and proximal EPB (2) identified before repairs.
EPL core suture (1) of 3-O braided non-absorbable being placed. Note distal end of EPB (2).
Core suture in the EPL being tied. Note some tension being applied to prevent post-operative gapping. Some bunching noted bot this will be improved with the epitendinous edge suture and will be tolerated in this subcutaneous location.
Epitendinous peripheral edge 6-O nylon suture (arrow) being placed.

CPT Codes for Treatment Options

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Common Procedure Name

Extensor tendon repair

CPT Description

Extensor tendon repair, dorsum/finger, single, primary; secondary; without free graft, each tendon

CPT Code Number

26418

Common Procedure Name

Extensor tendon repair

CPT Description

Repair, tendon or muscle, extensor, forearm and/or wrist; primary, single, each tendon or muscle

CPT Code Number

25270

Common Procedure Name

Extensor tendon repair (with graft)

CPT Description

Repair, tendon or muscle, extensor, secondary with tendon graft, forearm

CPT Code Number

25274

Common Procedure Name

Extensor tenolysis

CPT Description

Tenolysis, flexor or extensor tendon, forearm and/or wrist, single each tendon

CPT Code Number

25295

Common Procedure Name

Extensor tenolysis

CPT Description

Tenolysis, extensor tendon, hand or finger, each tendon

CPT Code Number

26445

Common Procedure Name

PIP joint release (capsulotomy)

CPT Description

Capsulectomy or capsulotomy; interphalangeal joint, each joint

CPT Code Number

26525

Common Procedure Name

Extensor tendon transfer

CPT Description

Tendon transfer or transplant, CMC area or dorsum of hand single w/o free graft

CPT Code Number

26480

Common Procedure Name

Tendon transfer

CPT Description

Tendon transplant or transfer flexor/extensor forearm and/or wrist, single each tendon

CPT Code Number

25310

CPT Code References

The American Medical Association (AMA) and Hand Surgery Resource, LLC have entered into a royalty free agreement which allows Hand Surgery Resource to provide our users with 75 commonly used hand surgery related CPT Codes for educational promises. For procedures associated with this Diagnostic Guide the CPT Codes are provided above. Reference materials for these codes is provided below. If the CPT Codes for the for the procedures associated with this Diagnostic Guide are not listed, then Hand Surgery Resource recommends using the references below to identify the proper CPT Codes.

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Hand Therapy

The three general options for rehabilitation after extensor tendon repair are complete immobilization, early active ROM, and controlled passive ROM only. Although there is still some debate as to which protocol is best, but most experts now agree that mobilization is preferred over immobilization.^1,16Most authors supporting mobilization favor dynamic splints where the extension is passive and the flexion is active, although a few have proposed early active flexion and extension.¹⁶Deciding on a specific rehabilitation program should be based on the quality of the repair and the likelihood of patient compliance, and individualized to fit each patient’s specific tendon pathology.^17.Complete immobilization is typically only prescribed to children and adults that demonstrate unreliability in following postoperative instructions.¹⁰

Complications

Complications^1,4,13

Mallet finger
Boutonniere deformity
Extensor lag
Complex regional pain syndrome
Bowstringing
Swan-neck deformity
Trigger finger
Tendon entrapment
Tendon rerupture
Infection

Outcomes

It is difficult to investigate outcomes of extensor tendon lacerations because of the great diversity of available management protocols, and high-quality evidence is lacking on which repair or rehabilitation regimen is superior; however, research generally suggests that most patients treated with surgical repair experience positive outcomes.^1,7,13,18-20
One study investigated a conservative management protocol for patients with partial extensor tendon lacerations involving 55-85% of the tendon in zones II, IV, and VI-VIII, which consisted of irrigation and wound closing—without tendon suturing—followed by early active ROM exercises.
- The intervention was found to be safe and effective, with all patients obtaining full ROM with no reports of extensor lag.¹³
Another study treated 17 partial extensor tendon lacerations of all zones with suturing and early protected motion, and obtained excellent results.¹⁹
A prospective, randomized, case-controlled study compared early passive ROM with immobilization and found that early motion led to superior results at 12 weeks.²⁰
One trial investigated the outcomes of extensor tendon lacerations in different anatomic zones, and found that there was a greater proportion of good and excellent results in zones III and V than the other zones.⁷

Video

Testing repaired EPL and EPB in OR with tenodesis effect

Pre-operative thumb Examination in patient with left EPL and EPB lacerations.

Key Educational Points

There is a prevailing assumption that extensor tendon lacerations are easy to manage because they generally have good outcomes, which may be due to the fact that finger/hand extension is not essential to normal function and small losses in extension are easily compensated for. It may also be due to the superficial location of the extensor tendons, which makes them more accessible than flexor tendons. This assumption may also explain the scarcity of the literature on the management of extensor tendon lacerations and on long-term outcomes following extensor tendon repair.¹⁸
Open traumatic wounds with a deep, narrow traumatic laceration should raise suspicion of concomitant tendon injuries.¹
Although the management of partial tendon lacerations has evolved over the past 50 years, much more research is needed to create a consensus in different aspects of treating these injuries.¹
The physical examination is the most important component of treatment management and is often sufficient for diagnosing the injury; however, barriers such as patient noncompliance, pain, foreign body, fracture, and neurological injury may all potentially interfere with the clinicians ability to perform a careful patient history and examination.^10,21
Routine radiographs are often performed to detect the presence of any foreign bodies or concomitant bony injuries.
Ultrasound and MRI are highly accurate for identifying extensor tendon lacerations, but are not typically needed when a proper physical examination is conducted.^10,21
In the finger in zones I, II, III and IV, the extensor tendon is thin and traditional core sutures are not always applicable.
Repairs of sharp open laceration of the terminal extensor tendon in Zone I should be repaired with a running suture which is reinforced with a silver skiold cross-stitch.
The strength of a tendon repair depends on the number of core sutures crossing the repair site; the thickness of suture (size); and the addition of an epitendinous edge suture.^17,22
Modern suture strength can exceed the strength of the tendon tissue. Failure then occurs as the suture pulls through the tendon’s collagen. Modern suture technique can decrease the risk of gap formation at the repair site and of suture pullout; however, in the end tendon healing is the deciding factor^,17,22
Some modern suture techniques may be very strong, but in the end not very practical because they are exceedingly complicated, take too much tourniquet time to perform or are too bulky and interfere with tendon gliding.
Whether core suture knots are placed in the repair site where they may represent a foreign body in the healing zone or placed in the periphery of the tendon where the knots may interfere with gliding and predispose to adhesions is another unsolved debate.
A locking suture has a loop that passes around a group of tendon fibers and “locks” against these fibers as tension is applied. To achieve locking with a modified Kessler suture technique, the transverse suture component passes volar or superficial to the longitudinal component of the Kessler core suture. A grasping suture on the other hand pulls through the tendon fibers as tension is applied. When performing a grasping modified Kessler technique, the transverse arm of the suture passes deep (dorsal) to the longitudinal component of the Kessler core suture. Grasping suture can fail by pulling through the tendon fiber and locking suture can fail by cutting through the tendon fiber that the suture Is tied around.^17,22
When performing tendon repairs, avoid repetitive unnecessary grasping of the tendon during retrieval of the tendon ends and while suturing. Minor damage to the epitenon can increase the likelihood of adhesions. Each needle pass count should be made as accurately as possible because repetitive passes in the wrong location will weaken the tendon and increase the chance of cutting the previously placed sutures.

References

New and Cited Articles

Tang JB, Amadio PC, Guimberteau JC, Chang J. Tendon Surgery of the Hand. Philadelphia: Elsevier; 2012.
Johnston, CS, Thommasen, HV and Thommasen, A. The occasional extensor tendon laceration repair. Can J Rural Med 2006;11(2):120-5. PMID: 16630440
Patillo, D and Rayan, GM. Open extensor tendon injuries: an epidemiologic study. Hand Surg 2012;17(1):37-42. PMID: 22351531
Griffin M, Hindocha S, Jordan D, et al. Management of extensor tendon injuries. Open Orthop J 2012;6:36-42. PMID: 22431949
Khor WS, Langer MF, Wong R, et al. Improving Outcomes in Tendon Repair: A Critical Look at the Evidence for Flexor Tendon Repair and Rehabilitation. Plast Reconstr Surg 2016;138(6):1045e-1058e. PMID: 27879606
de Jong JP, Nguyen JT, Sonnema AJ, et al. The incidence of acute traumatic tendon injuries in the hand and wrist: a 10-year population-based study. Clin Orthop Surg 2014;6(2):196-202. PMID: 24900902
Mehdinasab SA, Pipelzadeh MR, Sarrafan N. Results of primary extensor tendon repair of the hand with respect to the zone of injury. Arch Trauma Res 2012;1(3):131-4. PMID: 24396762
Schoffl V, Heid A, Kupper T. Tendon injuries of the hand. World J Orthop 2012;3(6):62-9. PMID: 22720265
Tuncali D, Yavuz N, Terzioglu A, et al. The rate of upper-extremity deep-structure injuries through small penetrating lacerations. Ann Plast Surg 2005;55(2):146-8. PMID: 16034243
Kamal RN, Yao J. Evidence-Based Medicine: Surgical Management of Flexor Tendon Lacerations. Plast Reconstr Surg 2017;140(1):130e-139e. PMID: 28654614
Gibson PD, Sobol GL, Ahmed IH. Zone II Flexor Tendon Repairs in the United States: Trends in Current Management. J Hand Surg Am 2017;42(2):e99-e108. PMID: 27964900
Chauhan A, Palmer BA, Merrell GA. Flexor tendon repairs: techniques, eponyms, and evidence. J Hand Surg Am 2014;39(9):1846-53. PMID: 25154573
Al-Qattan MM. Conservative management of partial extensor tendon lacerations greater than half the width of the tendon in manual workers. Ann Plast Surg 2015;74(4):408-9. PMID: 25749213
Pritsch T, Wong C, Sammer DM. Accuracy of Visual Estimates of Partial Flexor Tendon Lacerations. J Hand Surg Am 2015;40(12):2421-6. PMID: 26527592
Haimovici L, Papafragkou S, Lee W, et al. The impact of fiberwire, fiberloop, and locking suture configuration on flexor tendon repairs. Ann Plast Surg 2012;69(4):468-70. PMID: 22964669
Koul AR, Patil RK, Philip V. Complex extensor tendon injuries: early active motion following single-stage reconstruction. J Hand Surg Eur Vol 2008;33(6):753-9. PMID: 18694916
Comer GC, Gordon C, Yao J. Hand Therapy Modalities Following Extensor Mechanism Surgery. J Hand Surg Am 2015;40(10):2081-4. PMID: 26209562
Fischer CR, Tang P. Lacerations to Zones VIII and IX: It Is Not Just a Tendon Injury. Adv Orthop 2011;2011:261681. PMID: 21991409
Crosby CA, Wehbe MA. Early protected motion after extensor tendon repair. J Hand Surg Am 1999;24(5):1061-70. PMID: 10509286
Browne EZ, Jr., Ribik CA. Early dynamic splinting for extensor tendon injuries. J Hand Surg Am 1989;14(1):72-6. PMID: 2723371
Dezfuli, B, Taljanovic, MS, Melville, DM, et al. Accuracy of High-Resolution Ultrasonography in the Detection of Extensor Tendon Lacerations. Ann Plast Surg 2016;76(2):187-92. PMID: 26101990
Hotokezaka S, Manske PR. Differences between locking loops and grasping loops: effects on 2-strang core suture. J Hand Surg 1997; 22A:995-1003. PMID: 9471066
Reviews
Amirtharajah M, Lattanza L. Open extensor tendon injuries. J Hand Surg Am 2015;40(2):391-7. PMID: 25557773
Chauhan A, Jacobs B, Andoga A, Baratz ME. Extensor tendon injuries in athletes. Sports Med Arthrosc Rev2014;22(1):45-55. PMID: 24651290

Classics

Blue AI, Spira M, Hardy SB. Repair of extensor tendon injuries of the hand. Am J Surg 1976;132(1):128-32. PMID: 952327
Kontor JA. Extensor tendon injuries and repairs in the hand. Can Fam Physician1982;28:1159-63. PMID: 21286174

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