Arthrodesis

Arthrodesis

Principles

  1. Denude joints
  2. Surfaces are apposed in optimal position and stabilise
  3. Bone grafts are added in larger joints
  4. Splintage until union is evident
  5. Main complication is pseudarthrosis

Hip

Pseudarthrosis rate 0-10%
Back pain in ~ 60% (long term usually ~ 25 yrs post op)
Pain in the knee 50-55% (usually after ~ 24 yrs)
Fusion in adduction is associated with less back and knee pain than those fused in abduction.
Hip fused in adduction also has lower incidence of degenerative changes in ipsilateral knee and better gait pattern.

Position

5o Adduction
35-40o Flexion
Neutral rotation
Later conversion to THR can result in limp due to abductor weakness and positive Trendelenburg test.
Conversion to THR will however improve sitting comfort, may improve level of function, reduce back pain and knee pain.

Operative Technique

  1. Anterior Ilio-femoral approach, expose and dislocate the hip
  2. Remove cartilage from the femoral head and acetabulum
  3. All avascular bone must be removed
  4. Reduce joint and position 30o flexion, neutral Abduction / Adduction to 5o adduction and neurtral external rotation. (using a fracture table have leg horizontal as 30o lumbar lordosis produced in patients with a mobile lumbar spine).
  5. Add extra-articular graft if required
  6. Internal fixation using either CHS, Cobra plate, DC Plate, Cannulate screws etc
  7. Hip spica 2-4/12 and encourage weight bearing

Knee

 

Compression arthrodesis provides best results and shortest time to union.

Accurate fitting of concellous surfaces in correct position is of extreme importance.

Use TKR Cutting blocks.

Charnley (1948) used compression clamps with pins placed 4cm from the cut surfaces.

Use of two pins at either end will give better control of angular movement about the osteotomy.
Optimal Angle: 15-20o flexion

Indications:

Failed TKR,

Traumatic OA

Historically TB & other sepsis of knee joint

 

Operative Technique

Intramedullary Nails

External Fixator

Plates Fixation

 

Full-length antegrade nails

This refers to nails inserted antegrade from the piriformis fossa down across the

knee and into the tibia;

Disadvantages:
-entry through the piriformis fossa and IM femoral reaming down to the knee joint causes significant bleeding which cannot be diminished by a tourniquet;

– implant removal is especially difficult if there is implant failure;

– reaming across localized infected tissue may cause extensive femoral and tibial osteomyelitis;
– tibial-femoral mismatch requires use of a smaller nail which decreases stability;

 

Short nails inserted thru the knee joint:

– have become more popular due to ease of insertion and high union rate (over 90%);
– nail is driven retrograde into the femoral canal, and then is backed out down into the tibial medullary canal;

Advantages:
– piriformis fossa remains intact and therefore blood loss can be minimised  with a tourniquet;
– femoral-tibial mismatch is not a problem;
– implant failure is unlikely due to the smaller nail length;

Bone Grafting:

– posterior bone graft is placed before IM nail is inserted;
– should be performed at time of arthrodesis for cases with extensive bone loss;
– in presence of bone loss, cancellous bone-grafting, by increasing surface available for bone apposition, can improve the chances of success;
– bone graft should be placed about periphery of the arthrodesis site to allow revascularization from surrounding soft tissues;
– intramedullary circulation of the bone is usually compromised by prior implant and cement

Complications:

– complications inherent in intramedullary nailing include nail breakage, nail migration, and bone fracture.
– complications associated with intramedullary nailing for arthrodesis have been reported in 40 to 55 per cent of cases

Ankle

 

Indications

  1. Traumatic arthritis
  2. Avascular necrosis of the body of the talus (post traumatic)
  3. Infectious arthritis
  4. Equinus deformity not treatable by bracing
  5. Osteoarthritis or Rheumatoid arthritis of the ankle
  6. Salvage of failed TAR

Results are usually satisfactory with relief of pain achieved in 60 – 75% of cases

Position

  1. Neutral Dorsiflexion
  2. 5-10 degrees of external rotation
  3. 5 degree of hind foot valgus

Operative Technique

Cannulated Screw

Plate Fixation

Intramedullary Nail ( in Triple Arthrodesis)

Comprssion Arhrodesis using Cannulated Screw

  1. Use an anterior midline incision beginning ~ 10cm proximal to the ankle joint, ~ 2.5cm medial to the fibula to the third cuneiform
  2. Expose the distal 1/3 of the tibia and the ankle joint
  3. Remove the articular surface of the ankle joint using a micro-sagittal saw (make allowance for correction of any equinus deformity in resecting the talar surface)
  4. May need to divide the tibio-talar ligaments in order to expose the dome of the talus adequately
  5. If necessary perfrom a posterior release and ETA through a separate incision
  6. Position the surfaces and pass cross guide wires through tibia to talus after checking position under II fix with large cannulated screws

Post operative management:

1- note that even rigid fixation, 8 deg of flexion-dorsiflexion and 7 deg of torsional motion may occur;
2- average immobilization time until all casts are removed is 7-8 months;
3- allow unprotected weight-bearing only after bone trabeculation is seen across osteotomy site;

Complications

Delayed union

Malunion

Non Union

Arthrits involving other joint of foot