**2. Surgical techniques for primary flexor tendon repair**

### **2.1 General considerations**

Usually flexor tendon repair is performed in an emergency setup. In cases such as dirty trauma or crush injuries, debridement should be done to convert contaminated wound into a cleaner wound. All the injuries (fracture, skin loss, neurovascular bundles) are repaired simultaneously along with flexor tendon repair. However, if the surgeon does not possess enough expertise to treat such lesions, it's advisable to delay the repair till next appropriate time [12]. All injured flexor tendons should be repaired using proper instruments and under magnification in an operating room thus allowing atraumatic repair of such tendons. Cleaning of wound before tenorrhaphy and in certain circumstances administration of intravenous antibiotics just before, during and 6 hours after surgery is indicated. The tendon repair

is performed under axillary block anesthesia along with a pneumatic tourniquet applied at the level of the arm. The tourniquet is released Just before the wound closure in order to perform hemostasis and hence preventing formation of hematoma, infection, potential adhesion and fibrosis.

### **2.2 Incisions for exposure**

In order to provide better visibility and to allow atraumatic repair of injured tendons, the skin wound should be debrided and enlarged. The position of the finger and the shape of the initial lesion govern the method of extension of wound for exposure; a palmar zigzag approach (Bruner's incision) can be used to extend an oblique skin laceration; a midlateral approach can be used to extend transverse skin laceration. A palmar zigzag incision provides an excellent exposure but at the same time can lead to adhesions as well as scar tissue formation over the repaired tendon. The midlateral approach allows a direct repair of the injured flexor tendon and also preserves vascular transverse branches of neurovascular bundle. Midpalmar incisions and straight incisions that cross flexor creases should be avoided, as sharp angle in the raised skin flaps can result in tip necrosis. The wound needs to be extended in distal direction if tendon injury has occurred while fingers where in flexion and similarly wound needs to be extended proximally if at time of injury fingers where in extension.

Mid palmar transverse incision become sometimes necessary when proximal end of tendon has retracted to palmar level and if flexor tendon massage or flexion of wrist fails to deliver retracted proximal tendon end (**Figure 1**). The silicone tube is passed in retrograde direction into the palm, from superficialis chiasma up to proximal stump. The proximal end of injured tendon is attached to the silicone tube and pulled distally, delivering it back into wound. This procedure helps in avoiding traumatic injury to digital sheath and hence preventing adhesion formation (**Figure 2**) [13].

With an L-shaped incision (Lister's technique) the digital flexor tendon sheath is opened in between the annular pulleys [9]. to prevent bowstringing Annular pulleys (especially A2 and A4) should be spared and repaired if they are traumatized. The sheath should be closed using a fine suture material after completion of repair of severed flexor tendon. In case of severe damage to the sheath, it may be necessary to excise the portion of the sheath over the repaired tendon site to prevent trigger finger or an impingement. In cases where tendon injury is not a result of sharp cut, the tendon ends needs to be refreshed using a sharp blade, this debridement should be minimal to avoid any tension over the tenorrhaphy site. A needle can be used to fix proximal end in place while performing tenorrhaphy, this allows tension free approximation of two injured tendon ends (**Figure 3**).

**127**

**2.3 Suturing technique**

**Figure 2.**

*adhesions.*

**Figure 3.**

Various suturing techniques have been defined. Among these the modified Kessler suture using two sutures [14] and a 'grasping' suture [15, 16] having knots inside the cross-section have been widely accepted. A running fine epitendinous sutures increase the tensile strength and also allows smooth gliding of the repaired tendon within the digital sheath. However, immediate active rehabilitation is not possible after using these suturing techniques. Therefore, number of studies has been carried out to improve the suturing technique as well as the suturing material. The 'ideal' suturing material should be strong, pliable but non-reactive, and of small caliber. It is advisable to use Nylon 3/0 for the central suture and for the epitendinous running suturing its recommended to use nylon 5/0 or 6/0 [17]. The 'locking' or a 'grasping' suture [18, 19] with four or six strand sutures [20, 21] is considered to be ideal for central core suturing along with running epitendinous locking sutures [22]. This allows an immediate active rehabilitation programme as this suturing technique provides double strength than usual traditional suturing methods. Tsuge's suture [23] is easy method of performing 'locking' sutures, but it leaves a knot outside over the tendon repair site, which in turn can affect smooth gliding of flexor tendons within the synovial sheath or the pulley system. This new suturing method by virtue of strong repair, allows early active motion with minimal risk of gap formation or early tendon rupture. A new material has been reported which is characterized by its high traction resistance: it consists of two intratendinous, stainless steel anchors that are joined by a multifilament stainless steel suture.

*Temporary fixation of the proximal tendon stump with a needle to facilitate repair.*

*A silicone tube to bring the proximal tendon stump to the desired level to avoid potential formation of* 

*Management of Flexor Tendon Injuries in Hand DOI: http://dx.doi.org/10.5772/intechopen.83483*

**Figure 1.** *Bruner's incision with palmar incision to expose the tendon stumps.*

*Management of Flexor Tendon Injuries in Hand DOI: http://dx.doi.org/10.5772/intechopen.83483*

### **Figure 2.**

*Tendons*

infection, potential adhesion and fibrosis.

**2.2 Incisions for exposure**

fingers where in extension.

is performed under axillary block anesthesia along with a pneumatic tourniquet applied at the level of the arm. The tourniquet is released Just before the wound closure in order to perform hemostasis and hence preventing formation of hematoma,

In order to provide better visibility and to allow atraumatic repair of injured tendons, the skin wound should be debrided and enlarged. The position of the finger and the shape of the initial lesion govern the method of extension of wound for exposure; a palmar zigzag approach (Bruner's incision) can be used to extend an oblique skin laceration; a midlateral approach can be used to extend transverse skin laceration. A palmar zigzag incision provides an excellent exposure but at the same time can lead to adhesions as well as scar tissue formation over the repaired tendon. The midlateral approach allows a direct repair of the injured flexor tendon and also preserves vascular transverse branches of neurovascular bundle. Midpalmar incisions and straight incisions that cross flexor creases should be avoided, as sharp angle in the raised skin flaps can result in tip necrosis. The wound needs to be extended in distal direction if tendon injury has occurred while fingers where in flexion and similarly wound needs to be extended proximally if at time of injury

Mid palmar transverse incision become sometimes necessary when proximal end of tendon has retracted to palmar level and if flexor tendon massage or flexion of wrist fails to deliver retracted proximal tendon end (**Figure 1**). The silicone tube is passed in retrograde direction into the palm, from superficialis chiasma up to proximal stump. The proximal end of injured tendon is attached to the silicone tube and pulled distally, delivering it back into wound. This procedure helps in avoiding traumatic injury to

With an L-shaped incision (Lister's technique) the digital flexor tendon sheath is opened in between the annular pulleys [9]. to prevent bowstringing Annular pulleys (especially A2 and A4) should be spared and repaired if they are traumatized. The sheath should be closed using a fine suture material after completion of repair of severed flexor tendon. In case of severe damage to the sheath, it may be necessary to excise the portion of the sheath over the repaired tendon site to prevent trigger finger or an impingement. In cases where tendon injury is not a result of sharp cut, the tendon ends needs to be refreshed using a sharp blade, this debridement should be minimal to avoid any tension over the tenorrhaphy site. A needle can be used to fix proximal end in place while performing tenorrhaphy, this allows tension free

digital sheath and hence preventing adhesion formation (**Figure 2**) [13].

approximation of two injured tendon ends (**Figure 3**).

*Bruner's incision with palmar incision to expose the tendon stumps.*

**126**

**Figure 1.**

*A silicone tube to bring the proximal tendon stump to the desired level to avoid potential formation of adhesions.*

**Figure 3.** *Temporary fixation of the proximal tendon stump with a needle to facilitate repair.*

### **2.3 Suturing technique**

Various suturing techniques have been defined. Among these the modified Kessler suture using two sutures [14] and a 'grasping' suture [15, 16] having knots inside the cross-section have been widely accepted. A running fine epitendinous sutures increase the tensile strength and also allows smooth gliding of the repaired tendon within the digital sheath. However, immediate active rehabilitation is not possible after using these suturing techniques. Therefore, number of studies has been carried out to improve the suturing technique as well as the suturing material.

The 'ideal' suturing material should be strong, pliable but non-reactive, and of small caliber. It is advisable to use Nylon 3/0 for the central suture and for the epitendinous running suturing its recommended to use nylon 5/0 or 6/0 [17]. The 'locking' or a 'grasping' suture [18, 19] with four or six strand sutures [20, 21] is considered to be ideal for central core suturing along with running epitendinous locking sutures [22]. This allows an immediate active rehabilitation programme as this suturing technique provides double strength than usual traditional suturing methods. Tsuge's suture [23] is easy method of performing 'locking' sutures, but it leaves a knot outside over the tendon repair site, which in turn can affect smooth gliding of flexor tendons within the synovial sheath or the pulley system. This new suturing method by virtue of strong repair, allows early active motion with minimal risk of gap formation or early tendon rupture. A new material has been reported which is characterized by its high traction resistance: it consists of two intratendinous, stainless steel anchors that are joined by a multifilament stainless steel suture.

This permanent implant is intended to hold the repaired ends of tendon in close approximation until healing is completed. Protected passive tendon mobilization exercises are carried out after completion of tendon repair.

### **2.4 Postoperative management**

postoperatively, A dorsal plaster splint is applied, from the proximal forearm to the fingertips in 'intrinsic position': the wrist is kept with 20° of palmar flexion, the MP joints in 60° flexion while as PIP and DIP joints are placed in full extension in order to avoid development of any flexion contracture. Two possible options as post-operative protocol are: to immobilize operated hand for 4 weeks or to start early mobilization according to specific exercise protocol. Immobilization is better option in non-cooperative patients and in case of children, in these patients mobilization is started in fifth week, with combination of both active as well as passive motions with dorsal blocking splint in place; seventh week onwards mobilization against resistance is initiated. The complications like tendon rupture or gaping of repair are very low with this protocol, but there are increased chances of adhesion formation, which usually requires tenolysis. Strickland and Glogovac [24] and Lister et al. [25] studied the benefits of early mobilization for tendon healing with better final end results especially in zone II flexor tendon repairs. In these studies using controlled passive mobilization post-operatively excellent results were obtained in 36% patients, 24% patients had poor results and only 4% had tenorrhaphy ruptures; while as no excellent results were obtained in cases of immobilization protocol, poor results were observed in 44% patients and 16% had tenorrhaphy site ruptures. Gelberman et al. [26, 27] also obtained superior results with early mobilization protocol and additional advantages like: improved tendon gliding (due to low rate of soft tissue adherence), enhancement of intrinsic healing mechanism, with enhanced tensile strength thereby decreasing risk of gap formation. The highest risk of tenorrhaphy rupture is between 5th and 10th postoperative day, during this period the hand therapist should be very cautious while doing during active motion exercises.

Kleinert et al. [28] proposed active and passive mobilization with dorsal blocking plaster splint keeping wrist in flexion of 20°, MP joint in flexion of 70° and allowing complete extension of fingers. An elastic traction band is attached to a loop, which is fixed to nail, keeping fingers in flexion but at same time allowing active extension within the range of dorsal blocking splint (**Figure 4**). D first 4 weeks, the patients is asked to perform active extension of the fingers many times for half an hour periods every day at different intervals. For the rest of the day and during the night the rubber band traction is detached in order to prevent development of flexion contracture in interphalangeal joint. At the beginning, the exercises should be guided by the hand therapist keeping patients elbow flexed and pronated in order to relax the flexor muscles. Between the fifth and sixth post-operative weeks, active flexion is begun with dorsal blocking splint in place. This technique is excellent but highly demanding for the therapist, surgeon as well as patient, and a control at every step is necessary to prevent a rupture or a gap at the tendon repair site. A palmar pulley situated at the level of the distal palmar crease significantly improves the range of flexion of the fingers and hence better results have been reported. After repairing the flexor pollicis longus (FPL) in the thumb MP and IP joints are kept in 20° of flexion.

Duran and Hauser [29] proposed controlled passive motion for the post-operative flexor tendon repaired lesions in zone II. The wrist is kept in 20–30° of flexion, the MP joint in 60° of flexion while as PIP and DIP joints are placed in extension.

**129**

hand surgeon is very important.

in close collaboration with a hand surgeon.

*Management of Flexor Tendon Injuries in Hand DOI: http://dx.doi.org/10.5772/intechopen.83483*

*Kleinert's technique for passive flexion and active extension.*

**Figure 4.**

For first 4 weeks controlled passive motion is used, by the hand therapist, twice a day with each session of six to eight motions for each tendon. This method uses 3–5 minute exercise movements at the repair site for preventing any firm adhesion formation. For a week, a rubber band traction is attached to the wrist and active

Duran's technique was modified by Strickland [15]. He increased the duration and frequency of the passive daily exercises. The PIP and DIP joints are separately mobilized with repeated motions of full passive extension and flexion. An occupational therapist works closely with the operating hand surgeon and guides the controlled passive motion protocol during first 5 weeks. For starting the active flexion exercises after 5th week, the block technique advised by Bunnel [30] can be utilized: the PIP joint is actively flexed while the MP joint is blocked in extension; similarly while the DIP joint is actively flexed, the PIP joint is blocked in extension. Beyond 6 weeks, If the extension of the finger is limited, dynamic splinting may be necessary. Six months is the minimal period before considering any tenolysis and this is the time period that is required to obtain complete motion (especially in children). Excellent results were reported by Chow et al. [31] in a multicenter study carried

out for zone II flexor tendon injuries. They utilized rubber band traction with a palmar pulley at distal palmar crease level thus increasing passive flexion at the MP and PIP joints. This modification increases the differential gliding between superficialis and profundus tendon and in addition increases tendon excursion in the sheath as well. Full passive extension and flexion were performed for the first 4 weeks under the supervision of a hand therapist, in addition to the active extension exercise programme against the rubber band traction. The rubber band traction is removed for the fifth and sixth week and active and passive full flexion and extension exercises are performed. To prevent development of any contracture at the level of interphalangeal joints the supervision of both hand therapist and a

Many authors have reported their results using early active flexion exercises after performing flexor tendon repair in zone II [32–34]. to perform this rehabilitation programme it's important to Improve the quality as well as resistance of the suture, in order to prevent rupture or a gap of the tendon at the repair site. Indications for using early motion protocol is limited to motivated and intelligent patients having clean cut tendon injury, with a specialized hand therapist working

Magnetic resonance imaging (MRI) is very useful for diagnosing many postoperative complications especially in differentiating gap from adhesion formation,

especially in zone II after tenorrhaphy of FDS and FDP tendon injuries.

exercises are done for 2 weeks with dorsal blocking splint in place.

*Management of Flexor Tendon Injuries in Hand DOI: http://dx.doi.org/10.5772/intechopen.83483*

*Tendons*

This permanent implant is intended to hold the repaired ends of tendon in close approximation until healing is completed. Protected passive tendon mobilization

postoperatively, A dorsal plaster splint is applied, from the proximal forearm to the fingertips in 'intrinsic position': the wrist is kept with 20° of palmar flexion, the MP joints in 60° flexion while as PIP and DIP joints are placed in full extension in order to avoid development of any flexion contracture. Two possible options as post-operative protocol are: to immobilize operated hand for 4 weeks or to start early mobilization according to specific exercise protocol. Immobilization is better option in non-cooperative patients and in case of children, in these patients mobilization is started in fifth week, with combination of both active as well as passive motions with dorsal blocking splint in place; seventh week onwards mobilization against resistance is initiated. The complications like tendon rupture or gaping of repair are very low with this protocol, but there are increased chances of adhesion formation, which usually requires tenolysis. Strickland and Glogovac [24] and Lister et al. [25] studied the benefits of early mobilization for tendon healing with better final end results especially in zone II flexor tendon repairs. In these studies using controlled passive mobilization post-operatively excellent results were obtained in 36% patients, 24% patients had poor results and only 4% had tenorrhaphy ruptures; while as no excellent results were obtained in cases of immobilization protocol, poor results were observed in 44% patients and 16% had tenorrhaphy site ruptures. Gelberman et al. [26, 27] also obtained superior results with early mobilization protocol and additional advantages like: improved tendon gliding (due to low rate of soft tissue adherence), enhancement of intrinsic healing mechanism, with enhanced tensile strength thereby decreasing risk of gap formation. The highest risk of tenorrhaphy rupture is between 5th and 10th postoperative day, during this period the hand therapist should be very cautious while doing during active motion

Kleinert et al. [28] proposed active and passive mobilization with dorsal blocking plaster splint keeping wrist in flexion of 20°, MP joint in flexion of 70° and allowing complete extension of fingers. An elastic traction band is attached to a loop, which is fixed to nail, keeping fingers in flexion but at same time allowing active extension within the range of dorsal blocking splint (**Figure 4**). D first 4 weeks, the patients is asked to perform active extension of the fingers many times for half an hour periods every day at different intervals. For the rest of the day and during the night the rubber band traction is detached in order to prevent development of flexion contracture in interphalangeal joint. At the beginning, the exercises should be guided by the hand therapist keeping patients elbow flexed and pronated in order to relax the flexor muscles. Between the fifth and sixth post-operative weeks, active flexion is begun with dorsal blocking splint in place. This technique is excellent but highly demanding for the therapist, surgeon as well as patient, and a control at every step is necessary to prevent a rupture or a gap at the tendon repair site. A palmar pulley situated at the level of the distal palmar crease significantly improves the range of flexion of the fingers and hence better results have been reported. After repairing the flexor pollicis longus (FPL) in the thumb MP and IP

Duran and Hauser [29] proposed controlled passive motion for the post-operative

flexor tendon repaired lesions in zone II. The wrist is kept in 20–30° of flexion, the MP joint in 60° of flexion while as PIP and DIP joints are placed in extension.

exercises are carried out after completion of tendon repair.

**2.4 Postoperative management**

**128**

joints are kept in 20° of flexion.

exercises.

**Figure 4.** *Kleinert's technique for passive flexion and active extension.*

For first 4 weeks controlled passive motion is used, by the hand therapist, twice a day with each session of six to eight motions for each tendon. This method uses 3–5 minute exercise movements at the repair site for preventing any firm adhesion formation. For a week, a rubber band traction is attached to the wrist and active exercises are done for 2 weeks with dorsal blocking splint in place.

Duran's technique was modified by Strickland [15]. He increased the duration and frequency of the passive daily exercises. The PIP and DIP joints are separately mobilized with repeated motions of full passive extension and flexion. An occupational therapist works closely with the operating hand surgeon and guides the controlled passive motion protocol during first 5 weeks. For starting the active flexion exercises after 5th week, the block technique advised by Bunnel [30] can be utilized: the PIP joint is actively flexed while the MP joint is blocked in extension; similarly while the DIP joint is actively flexed, the PIP joint is blocked in extension. Beyond 6 weeks, If the extension of the finger is limited, dynamic splinting may be necessary. Six months is the minimal period before considering any tenolysis and this is the time period that is required to obtain complete motion (especially in children).

Excellent results were reported by Chow et al. [31] in a multicenter study carried out for zone II flexor tendon injuries. They utilized rubber band traction with a palmar pulley at distal palmar crease level thus increasing passive flexion at the MP and PIP joints. This modification increases the differential gliding between superficialis and profundus tendon and in addition increases tendon excursion in the sheath as well. Full passive extension and flexion were performed for the first 4 weeks under the supervision of a hand therapist, in addition to the active extension exercise programme against the rubber band traction. The rubber band traction is removed for the fifth and sixth week and active and passive full flexion and extension exercises are performed. To prevent development of any contracture at the level of interphalangeal joints the supervision of both hand therapist and a hand surgeon is very important.

Many authors have reported their results using early active flexion exercises after performing flexor tendon repair in zone II [32–34]. to perform this rehabilitation programme it's important to Improve the quality as well as resistance of the suture, in order to prevent rupture or a gap of the tendon at the repair site. Indications for using early motion protocol is limited to motivated and intelligent patients having clean cut tendon injury, with a specialized hand therapist working in close collaboration with a hand surgeon.

Magnetic resonance imaging (MRI) is very useful for diagnosing many postoperative complications especially in differentiating gap from adhesion formation, especially in zone II after tenorrhaphy of FDS and FDP tendon injuries.
