- Flexor and extensor injuries are common
- Flexor tendon injuries are often associated with neurovascular
damage
- Extensor tendon injuries often associated with articular damage
- Require careful assessment and management
- Assessment should be based on accurate knowledge of tendon anatomy
- Accurate surgical repair required requiring meticulous surgical
technique
- If poorly managed can lead to significant functional disability
Anatomy
Flexor tendons
- Flexor tendons run a fibro-osseous canals
- Flexor digitorum superficialis inserts into middle phalanx
- Flexor digitorum profundus inserts into distal phalanx
- Metacarpals and phalanges form the dorsal wall
- Synovial sheaths form the volar and lateral walls
- Synovial sheath for index to ring finger begins at neck of
metacarpals
- Synovial sheath of little finger is continuous with ulna bursa
- Sheath thickened to form pulleys (A1 to A5)
Extensor tendons
- Extensor tendons are extra-synovial, except at the wrist
- Surrounded by extensive paratenon with segmental arterial input
- Extensor retinaculum prevents bowstringing of the extensors
- Main action is extension of the MCP joints
Zone of injury
Flexor tendons
- Flexor tendons are divided into 5 zones
- Zone 1 is distal and Zone 5 is proximal
- The five zones are
- 1 - contains flexor digitorum profundus only distal to the
insertion of flexor digitorum superficialis
- 2 - from insertion of flexor digitorum superficialis to the
proximal edge of the A1 pulley
- 3 - from the proximal edge if the A1 pulley to the distal edge of
the carpal tunnel
- 4 - within the carpal tunnel
- 5 - proximal to the carpal tunnel
Extensor tendons
- Extensor tendons are divided into 8 zones
- Zones 1,3 and 5 lie over the DIP, PIP and MCP joints
Assessment
- Accurate history required
- Important to know handedness and patients occupation
- Observing hand at rest my indicated tendons involved
- Level of tendon injury may corresponds to site of any laceration -
but not always
- If both flexor tendons divided the finger will be extended
- If profundus tendon alone divided then only the DIP will be extended
- Further assessment should involve testing of individual tendons
- Flexor digitorum superficialis
- Flexor digitorum profundus
- Neurovascular assessment also required
Flexor tendon injuries
- Early exploration and repair is required
- Ideally surgery should be performed within 24 hours
- Primary repair is the gold standard
- Primary repair may not be possible id delayed presentation or
tendons retracted
- Antibiotic prophylaxis required if delayed presentation or would
contamination
- The ideal tendon repair requires
- Sutures easily placed in the tendon
- Secure suture knots
- Smooth junction if the tendon ends
- Minimal gapping at repair site
- Minimal interference with tendon vascularity
- Sufficient repair strength
- Many techniques of tendon repair have been described
- They invariably involve
- Core suture
- Epitendinous suture
Picture supplied by Joy Treasure, Lyell McEwin Health
Service, Elizabeth Vale, South Australia
Zone 1 injuries
- Direct repair usually possible
- Periosteal flap raised and tendon anchored with a core suture
Zone 2 to 5 injuries
- Wounds should be excised and irrigated
- May need to be extended to retrieve and repair tendons
- Avoid incisions that cross skin creases
- Careful planning required to prevent skin necrosis or contracture
- Incision may be required in tendon sheaths between the main pulleys
- Neurovascular bundles should be identified and repaired is necessary
- Tendons should be repaired using a standard technique
Post-operative management
- After repair the hand should be placed in a back-slab with
- Wrist at 0 - 30 degrees
- MCP joints at 60 - 90 degrees
- PIP and DIP joints in full extension
- Hand should be elevated to reduce swelling
- Early mobilisation required to
- Reduce adhesion formation
- Improve tendon healing
- Improve final outcome
- Requires close supervision by hand physiotherapist
- Mobilisation can begin as early as first postoperative day
- Passive extension should be avoided
Extensor tendon injuries
- Open exploration and repair is required
- Can often be performed under local anaesthetic
- Management depends on the zone of the injury
- Proximal injuries require immobilisation with the wrist extended and
the MCP joint flexed
- Active movement can begin after 3 weeks
- Distal injuries require longer period of immobilisation
Bibliography
Bell Krotoski J A. Flexor tendon and peripheral nerve repair.
Hand Surg 2002; 7: 83-109
Chu M M. Splinting programmes for tendon injuries. Hand
Surg 2002; 7: 243-249.
Thien T B, Becker J H, Theis J C. Rehabilitation
after surgery for flexor tendon injuries in the hand. Cochrane
Database Syst Rev 2004; 4: CD003979 |