allograft

Definition

Defect of cartilage +/bone

Typically on talus

Options

Distal Tibial Allograft

Indication

Bony defects > 30 %

Options

- Latarjet - may be insufficient for lesions in the region of 50%

- Iliac crest - associated with high incidence of OA
- distal tibial allograft - radius of curvature matches glenoid highly

Bone Healing

Bone healing requires 3 things

- osteoconduction - scaffold / matrix

- osteoinduction - growth factors

- osteogenesis - cells  to produce osteoid

Osteoconduction

Definition

- property of a matrix that supports the attachment of bone forming cells for subsequent bone formation

Substances

Scenarios

1.  Isolated LCL injury

2.  Isolated Posterolateral Corner

3.  PCL + posterolateral corner

4.  ACL / posterolateral corner

5.  ACL / PLC / posterolateral corner

Repair versus Reconstruction

Levy et al. Am J Sports Med 2010

- failure in 4/10 knees treated with acute primary repair

Epidemiology

Usually occurs in patients over 60

- due to decreased vascularity & collagen weakness

Younger patient on steroids / growth hormone

Occasionally occurs in young athlete with excessive contracture

Aetiology

Often preceded by quadriceps tendinosis

Timing of Surgery

Issue

- reported higher incidence with immediate reconstruction in acute phase

- reduced by settling inflammation / effusion and obtaining FROM

- always best to delay if not professional athlete

- problematic if patient has locked bucket handle mensical tear

Results

Bottoni et al Am J Sports Med 2008

- RCT of early (average 9 days) v late reconstruction (average 85 days)

Graft Preparation

Defrost

- in 2 litres normal saline

- can add vancomycin powder

Choose which part of graft to use

- usually central third

- can take either side

- try to leave sufficient graft in case of disasters

- i.e. dropping or rupturing graft

Graft selection

A.  Synthetic Grafts

Good initial results but unacceptably high failure rate with longer follow-up

Problems

1.   Too stiff (low ultimate strain) 

- poor resistance to abrasion

- ligament failure by attrition most common

2.  Recurrent synovitis, infection, loosening and osteolysis

B.  Autograft

Issues

Rule out infection

Assess rotator cuff / bone stock preoperatively

Approach

- difficult / scarring +++

- very difficult to restore any loss of ROM

Removal of prosthesis

Glenoid

- may not be able to revise

Humeral component

- long stem

Investigations

Rule out infection

- CRP / ESR

- ultrasound or xray guided aspiration