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Dr Michael Kain, Orthopaedic Hip Surgeon, Hip Reconstruction, Hip Surgery, Boston, Massachusetts | Patient Info | Hip | Procedures | AMIC of the Hip

AMIC of the Hip

AMIC of the Hip

What is Hip Autologous Matrix-Induced Chondrogenesis (AMIC)?

Hip AMIC is a surgical procedure to repair chondral (cartilage) defects like lesions in your hip. Chondral defects, also called chondropathies, occur at the acetabulum (socket) and femoral (thigh bone) head of your hip joint. 

Indications for AMIC

The indications for hip AMIC can be:

  • Chondral lesions on the acetabulum or femoral head
  • Frequent pain in your hip and functional limitation

How do You Prepare for the Procedure?

Before the procedure, your surgeon is likely to tell you the following:

  • Avoid taking certain medications or dietary supplements
  • Quit or reduce smoking (if applicable) two weeks before your surgery
  • Stop eating solid foods eight hours before the procedure
  • Arrange for an escort home after the procedure 

How is AMIC Performed?

AMIC is performed in two stages.

Stage 1: Microfracture (marrow-stimulation from blood clot) 

  • You will be placed in the lateral decubitus position (on your side) for hip access.
  • A small incision is made into the hip joint and an arthroscopic probe is inserted. 
  • The chondral defect is visualized, and the location of the defect is verified.
  • The size of the chondral defect is measured to prepare the collagen matrix.
  • A dry matrix is then cut to fit the size and shape of the defect.
  • The defective cartilage is removed by using angled curettes or motorized shavers. 
  • Microfracture is performed on the subchondral bone (bone layer below the cartilage). 
  1. The subchondral bone is scored using a sharp-angled awl. 
  2. Tiny fracture holes are then created in the bone.

Microfracture allows blood and stem cells to form a clot and ultimately a cartilage layer within the defect area. 

Stage 2: Application of collagen matrix

  • Any residual fluid and tissues are carefully removed from the joint.
  • The matrix, with the porous layer facing the bone surface, is placed on the defect area.
  • A series of 4 to 6 extension and rotation movements is performed. 
  • The position of the matrix is verified to ensure it remains in place. 
  • Autologous (from your body) fibrin glue is applied to secure the matrix.
  • The incision is closed with sutures to complete the procedure.

Risks Associated with the Procedure

Though rare, AMIC may lead to risks such as: 

  • Infection or interruption of blood supply to the femoral head
  • Slow wound-healing and prolonged recovery time 
  • Mild but persistent pain in the hip especially during full weight-bearing

What Precautions should be Taken as You Recover from the Procedure?

As you recover from the procedure, you may be required to:

  • Walk with the aid of crutches for the first three weeks
  • Walk with the aid of one crutch at 4 weeks for 1 week then resume normal walking 
  • Wait for three months before resuming minor sports activities 

Benefits of AMIC

Currently, AMIC is considered as the first-line technique to treat chondral defects in the hip. Its benefits include:

  • Minimally invasive one-step procedure
  • Shorter hospitalization time and faster rehabilitation
  • Results in a pain-free hip joint with a high range of motion
  • Safe, with low risk of complications
  • A cost-effective treatment option 
  • Long-term success and favorable outcomes
  • Higher patient satisfaction