Three phases of tendon healing

Inflammation​ (first week) - cell proliferation and clean up

Proliferation (week 2-4) - fibroblasts and capillary buds migrate in and produce random collagen

Remodelling (months 2-6) - longitudinal organisation of collagen fibres in line with stress

Tendons with paratenon​

Fibroblasts and capillary buds migrate into the injured area​

Tendons with synovial sheath (controversial)

Extrinsic - fibroblasts migrate from the sheath into the injured site (also form adhesions)​

Intrinsic - tenocytes migrate across closely approximated ends and heal with nutrients from synovial fluid

Disclaimer: The following are the editor's preferred repair methods (please use with guidance from your own unit)

Zone 1:

• Closed non-bony - Splint DIPJ in full extension 8-10 weeks​

• Closed with fracture <50% articular surface - Splint as above

• Closed with fracture ≥50% articular surface - Percutaneous K-wire fixation (Ishiguru technique), ORIF screw fixation

• Open injury - continuous running 4-0/5-0 Ethilon and splint for 6 weeks in extension

• Local flap reconstruction may be necessary inadequate soft tissue coverage for tendon repair

Zone 2:​

• Partial laceration <50% - repair not required​, active motion after wound healed

• Partial laceration ≥50% - continuous running 4-0/5-0 Ethilon suture, splint DIPJ for 6 weeks

• Thumb - core 4-0 Ethilon modified Kessler, continuous running epitendinous 5-0 Ethilon, splint IPJ for 6 weeks

Zone 3:​

• Closed avulsion (boutonniere injury) - splint PIPJ in full extension for 6 weeks with MPJ and DIPJ​ free

• Open injury - Core 4-0 Ethilon modified Kessler, continuous running epitendinous 5-0 Ethilon, splint PIPJ in full extension for 6 weeks with MPJ and DIPJ​ free

• Use anchor suture if stump of central slip too short for suture repair

Zone 4:​

• Usually open: Core 4-0 Ethilon modified Kessler, continuous running epitendinous 5-0 Ethilon, splint with wrist 20-30° extension, MPJ 70-90° flexion and IPJs full extension

Zone 5:​

• Beware of fight bite injury​, which may not be suitable to primary tendon repair and may require urgent washout of MCPJ

• Look for superficial radial nerve injury in thumb extensor injuries

• Repair as for zone 4 injury

• Open sagittal band laceration - 4-0/5-0 Ethilon epitendinous suture, splint MPJ in full extension for 3-5 days, then gentle flexion and extension exercises

• Thumb - repair as for zone 3 injury

Zone 6-9:​

• Tendon bodies repaired with core and epitendinous suture as per zone 3​

• Muscle bellies opposed with figure-of-8 3-0 PDS

• Splint according to tendon repaired (including elbow if tendon originating from above elbow)

• Beware of nerve injuries

For general considerations on splinting, see Flexor tendons​

Rupture

Adhesions

Extensor imbalance - swan neck deformity, boutonniere deformity, extrinsic/intrinsic tightness

Usually requires staged reconstruction after degloving injuries to the hand

1st stage - obtain adequate skin coverage with or without placement of silicone implants

2nd stage (wait about 3 months) - tendon graft