*2.5.1 Zone I*

Only the FDP is involved in traumatic lesion of this zone. As the intact vincular system limits the retraction of the tendon hence the severed proximal stump is easy to find. The end to end tenorrhaphy can be done directly if the distal stump is more than 1 cm in length. In case the distal stump is less than 1 cm in length, it is recommended to reinsert the proximal tendon end into the distal phalanx. It is done as double attachment: At the base of the distal phalanx to a subperiostal flap from the palmar aspect and second attachment is distally at the mid nail plate level after passing through the distal phalanx (**Figure 5**) [35]. A4 pulley should be preserved to prevent bowstringing but the A5 pulley is frequently partially opened.

Avulsion injury of the FDP is relatively a common injury in athletes but often the diagnosis is made late. As any finger can be involved in such injury but the ring finger is most commonly involved. The diagnosis is made in an emergency set up, when an athlete is unable to actively flex the distal phalanx. A lateral radiograph should be carried out routinely, to look for a small bone at the level of the PIP or DIP joint that is actually avulsed from the base of distal phalanx. Three main factors govern the prognosis in such lesion:


This injury is classified into three types as per Leddy and Parker [36]:


**131**

*2.5.2 Zone II*

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

with dorsal protective splint in place.

results can obtained after repair in this type.

once proper repair is done in this type of injury.

tion or worsening of intact FDS tendon functioning.

functional loss but Al pulley should be preserved.

necessary after 6 months of repair.

bowstringing or limitation in thumb motion.

fragment blocked into the A3 or A2 pulley can be seen in the lateral radiograph. Early reinsertion should be performed or later but within period of 3 months provided vascular supply of the severed tendon is preserved. Satisfactory

• Type III: in this type a large bony fragment is avulsed from the distal phalanx and caught at the level of A5 or A4 pulley. As the retraction is limited hence vascularization of the severed tendon is spared. There is excellent prognosis

Immediately after repair an active rehabilitation programme should be started

Type IIIA lesion as reported by Robins and Dobyns [37]: In this a large bony fragment is fractured from the distal phalanx base and FDP is retracted to the level of PIP joint. Treatment comprises of reduction and an internal fixation of the distal phalanx along with reinsertion of the avulsed FDP tendon. If an avulsion injury is missed in early period, later the treatment will depend upon the degree of motivation of the patient and presence of symptoms (pain, swelling, tenderness and tumefaction) and If the patient has pain or difficulty in movement at the base of the finger it is advisable to excise the FDP tendon. Tenodesis or fusion of the DIP joint can be considered if the

Two stage flexor tendon reconstruction of the FDP tendon in zone I is indicated in selective patients; skilled technicians and musicians. It is important to explain the patients the possibility of complications like PIP joint contracture, adhesion forma-

In the thumb, if the direct repair is not possible, proximal tendon stump can be lengthened by 1–3 cm using tendinous lengthening procedures. A Z-lengthening at the wrist level [38] can give 2–3 cm of advancement and more proximally at the musculo-tendinous junction a fractional lengthening [39] produces an advancement of about 1 cm. The A2 pulley can be partially excised if required without any

Traumatic lesion in this zone of the finger involves both FDP and FDS tendons, which are most often retracted into the palm (**Figures 6** and **7**). It is recommended to repair both the injured tendons as repairing the FDS tendon preserves the vinculum system which ensures blood supply to the FDP tendon and in addition it maintains a smooth bed for FDP gliding. If only the FDP tendon is repaired and the FDS tendon is excised, it removes the vinculum system at the same time. However, in case both tendons are repaired there are significant chances of developing adhesions between the two tendons especially at the repair site and it may make tenolysis

In the thumb zone II injury causes the FPL trauma, which slips into the palm, and its retrieval gets difficult. In order to locate the proximal stump a small incision is made at the wrist level. This simple approach is adopted to avoid any damage to the carpal tunnel, the thenar eminence and to the cutaneous branch of the median nerve. A similar technique of passing the silicone tube as that used for retrieval of the FDS and the FDP tendons in fingers is used to bring the FPL tendon atraumatically into the initial wound for tenorrhaphy. It is recommended to preserve the A1 or oblique pulley and in case these pulleys are traumatized they need to be reconstructed using the abductor pollicis brevis aponeurosis for prevention of any

distal phalanx is unstable with weak pinch and an excessive dorsal extension.

*2.5.1 Zone I*

**2.5 Zone wise features of primary tendon repair**

govern the prognosis in such lesion:

tion of the avulsed tendon.

3.The size of the bony fragment avulsed.

2.Any diagnostic delay.

DIP joint can be chosen.

Only the FDP is involved in traumatic lesion of this zone. As the intact vincular system limits the retraction of the tendon hence the severed proximal stump is easy to find. The end to end tenorrhaphy can be done directly if the distal stump is more than 1 cm in length. In case the distal stump is less than 1 cm in length, it is recommended to reinsert the proximal tendon end into the distal phalanx. It is done as double attachment: At the base of the distal phalanx to a subperiostal flap from the palmar aspect and second attachment is distally at the mid nail plate level after passing through the distal phalanx (**Figure 5**) [35]. A4 pulley should be preserved to

Avulsion injury of the FDP is relatively a common injury in athletes but often the diagnosis is made late. As any finger can be involved in such injury but the ring finger is most commonly involved. The diagnosis is made in an emergency set up, when an athlete is unable to actively flex the distal phalanx. A lateral radiograph should be carried out routinely, to look for a small bone at the level of the PIP or DIP joint that is actually avulsed from the base of distal phalanx. Three main factors

1.Remaining nutritional supply to the avulsed tendon and the degree of retrac-

• Type I: complete destruction of the vincular system with FDP retracted into the palm. In an emergency setup, it is advisable to carry out a reinsertion of the severed FDP, but there is significant risk of adherence formation and causing dysfunction of the intact FDS. Alternatively, conservative method of not reinserting severed FDP tendon and excising the FDP tendon with fusion of the

• Type II: FDP is retracted to the level of the PIP joint and in this type the vincular system is intact. From all the three this is commonest one. A small bone

prevent bowstringing but the A5 pulley is frequently partially opened.

This injury is classified into three types as per Leddy and Parker [36]:

*Reinsertion of the avulsed tendon through the distal phalanx and fixed on the nail plate.*

**130**

**Figure 5.**

fragment blocked into the A3 or A2 pulley can be seen in the lateral radiograph. Early reinsertion should be performed or later but within period of 3 months provided vascular supply of the severed tendon is preserved. Satisfactory results can obtained after repair in this type.

• Type III: in this type a large bony fragment is avulsed from the distal phalanx and caught at the level of A5 or A4 pulley. As the retraction is limited hence vascularization of the severed tendon is spared. There is excellent prognosis once proper repair is done in this type of injury.

Immediately after repair an active rehabilitation programme should be started with dorsal protective splint in place.

Type IIIA lesion as reported by Robins and Dobyns [37]: In this a large bony fragment is fractured from the distal phalanx base and FDP is retracted to the level of PIP joint. Treatment comprises of reduction and an internal fixation of the distal phalanx along with reinsertion of the avulsed FDP tendon. If an avulsion injury is missed in early period, later the treatment will depend upon the degree of motivation of the patient and presence of symptoms (pain, swelling, tenderness and tumefaction) and If the patient has pain or difficulty in movement at the base of the finger it is advisable to excise the FDP tendon. Tenodesis or fusion of the DIP joint can be considered if the distal phalanx is unstable with weak pinch and an excessive dorsal extension.

Two stage flexor tendon reconstruction of the FDP tendon in zone I is indicated in selective patients; skilled technicians and musicians. It is important to explain the patients the possibility of complications like PIP joint contracture, adhesion formation or worsening of intact FDS tendon functioning.

In the thumb, if the direct repair is not possible, proximal tendon stump can be lengthened by 1–3 cm using tendinous lengthening procedures. A Z-lengthening at the wrist level [38] can give 2–3 cm of advancement and more proximally at the musculo-tendinous junction a fractional lengthening [39] produces an advancement of about 1 cm. The A2 pulley can be partially excised if required without any functional loss but Al pulley should be preserved.

### *2.5.2 Zone II*

Traumatic lesion in this zone of the finger involves both FDP and FDS tendons, which are most often retracted into the palm (**Figures 6** and **7**). It is recommended to repair both the injured tendons as repairing the FDS tendon preserves the vinculum system which ensures blood supply to the FDP tendon and in addition it maintains a smooth bed for FDP gliding. If only the FDP tendon is repaired and the FDS tendon is excised, it removes the vinculum system at the same time. However, in case both tendons are repaired there are significant chances of developing adhesions between the two tendons especially at the repair site and it may make tenolysis necessary after 6 months of repair.

In the thumb zone II injury causes the FPL trauma, which slips into the palm, and its retrieval gets difficult. In order to locate the proximal stump a small incision is made at the wrist level. This simple approach is adopted to avoid any damage to the carpal tunnel, the thenar eminence and to the cutaneous branch of the median nerve. A similar technique of passing the silicone tube as that used for retrieval of the FDS and the FDP tendons in fingers is used to bring the FPL tendon atraumatically into the initial wound for tenorrhaphy. It is recommended to preserve the A1 or oblique pulley and in case these pulleys are traumatized they need to be reconstructed using the abductor pollicis brevis aponeurosis for prevention of any bowstringing or limitation in thumb motion.

**Figure 6.** *Flexor tendon injuries in zone II, Bunnell's "no man's land".*

**Figure 7.** *Result in flexion after 6 months of modified Kessler suture and Kleinert's rehabilitation.*
