Wound Problems

TKR Wound ComplicationIncidence

 

10 -15%

 

Include

- marginal necrosis

- wound slough

- sinus tract formation

- dehiscence

- haematoma

- oozing knee wound

 

Blood supply

 

Anterior knee has no muscles to supply vessels directly 

- dermal plexus

- any subcutaneous dissection disrupts this & potentiates necrosis

- any skin flaps raised must be below subcutaneous fascia

 

Blood supply comes across medially

 

Prevention

 

1.  Avoid closely parallel scars

- 7 cm bridge is minimum

- use most lateral of 2 incisions

 

2.  Gentle tissue handling

 

3.  Avoidance of undermining & thin skin layers

 

4.  Careful closure of deep layer

- watertight, prevents oozing

 

TKR Watertight closure

 

5.  Closure with knee in flexion

 

6.  Avoid CPM

- >40° on first 3 days post-op associated with decreased oxygen tension

 

7.  Lateral Release 

- decreased skin O2 tension

- attempt to preserve SLGA

 

Concerns preoperatively

 

1.  Consult plastic surgeon

2.  Sham incision

3.  Tissue expanders

4.  Pre-op flap

- pedicled medial gastrocneumius flap + SSG

 

Patient Related Factors

 

1.  Steroids 

- decreased fibroblast proliferation necessary for wound healing

2.  RA

3.  DM

4.  Obesity 

- exposure, fat has poor and tenuous blood supply

5.  Malnutrition 

- Alb<3.5gm/L

- lymphcytes <1500 cells/L

6.  Smoking

7.  Chemo 

- MTX slight inc in wound healing problems? others none

8.  Hypovolaemia

 

Continuous Haemo-Serous drainage

 

Prolonged drainage

- 17-50% eventually become culture proven infection

 

Early management

- immobilise in splint

- local wound care

- cease anticoagulation / LMWH / Aspirin / NSAIDS

- trial vac dressing (drains haematoma / keeps sterile)

 

Drainage

- timing debatable

- rationale is that the wound in this situation is not a closed system 

- that bacteria are entering the wound while it is still draining 

- maybe better to reopen wound and debride it 

- commonly find subcutaneous or deep haematoma as cause

 

Non-Draining Haematoma

- no evidence to support drainage

- drain if causing excessive soft tissue tension or restriction of motion

 

Superficial Soft Tissue Necrosis

 

Management

- aggressive surgical debridement & closure

- < 3cm in diameter should heal

- > 3cm needs formal debridement and skin closure with SSG, flap etc

 

Full Thickness Soft Tissue Necrosis

 

Metal on view

- necessitates immediate, extensive debridement 

- medial gastrocnemius flap