ACL Surgery Graft Failure Symptoms

Anterior cruciate ligament (ACL) reconstruction surgery may need revision surgery due to graft failure. The ACL reconstruction is a highly successful surgery and only a few cases may need revision surgery.

The cause of revision surgery is mainly graft failure following ACL reconstruction surgery. The graft failure occurring in the first 12 months following surgery is generally a result of non-traumatic causes and the failure after 12 months is mostly due to re-injury.

During an ACL reconstruction surgery, the surgeon utilizes an arthroscope. An arthroscope has a minute camera with a light source which is inserted in the knee joint using a keyhole incision. Through another incision, miniature instruments are inserted. The surgeon uses the camera feed on an outside tv monitor to guide the instruments.

The ACL is reconstructed utilizing a graft that may be harvested from the patient’s own body known as autograft or may be harvested from a cadaver known as an allograft. A tunnel is created in the upper end of the shinbone and the lower end of the thigh bone.

The graft is passed through the tunnel and secured using screws, endo-buttons, etc. The ACL reconstruction surgery is followed by a rehabilitation protocol to help the patients get back to their activities of daily living and subsequent sports/athletic activities in the case of athletes.

Symptoms of ACL graft failure

• Patients may complain of a limp while walking and a feeling of looseness in the knee.
• There may be knee pain that may increase with activities.
• Patients may complain of knee stiffness, knee swelling, or instability while activities of daily living.
• Instability after an injury may point towards graft failure.

Causes

• Patients who receive ACL grafts in the form of allograft may develop graft rejection. Although rare, the cadaveric graft may cause the body’s immune system to react to it as an adverse substance. The subsequent inflammation may cause the subsidence of the allograft. Immunological allograft rejection is more common in younger patients.|||
• Overzealous or aggressive rehabilitation following the ACL reconstruction surgery may lead to loosening of the graft attachment in the shin bone or the thigh bone.
• Wrong ACL reconstruction techniques are the most common cause of ACL graft failure.
  • Mal-position of the tunnel for the ACL graft may place abnormal stress on the graft that may lead to loosening and subsequent failure. Anatomical placement of the graft in the natural position of the ACL is important to prevent graft failure.
  • Weak fixation of the graft to the bony attachment at the shin bone or the thigh bone may lead to loosening or rupture. The graft needs to be securely attached at either end of the tunnel to prevent prolapse.
  • The graft may also get impinged in the notch of the lower end of the thigh bone due to mal-position or due to the inherent shape of the notch.|
• Re-injury may cause graft failure, especially in athletes. The amount of force required for rupture of the reconstructed graft is significantly more as the graft is stronger than the natural ACL.
• Missing the diagnosis of additional injuries before and during the surgical reconstruction of the ACL may lead to instability. The instability of the joint despite the ACL reconstruction may lead to its failure. Usually, posterolateral corner injuries or meniscal tears may be missed during the ACL reconstruction and the subsequent instability may put additional stress on the ACL graft.
• Poor healing of the graft due to excessive scar tissue formation or due to systemic diseases may cause subsequent graft failure.

Diagnosis and Management of ACL graft failure

The diagnosis of the ACL graft is made after a thorough physical examination and radiological studies. The physician may perform physical examination tests to look for instability and alignment. Radiological studies in the form of plain and weight-bearing X-rays may be done. The surgeon may look for alignment of the hip joint and the ankle joint with the knee joint to assess the cause of instability.

A CT scan or an MRI may be done to evaluate the cause of failure. MRI and CT scans may provide information regarding the bony tunnel. Based on the diagnosis, the management may or may not involve surgery.

A revision ACL reconstruction surgery may be done in a single-stage or may require two stages in patients who may need bone grafting. The revision surgery may utilize an autograft or an allograft. The surgical technique involves the removal of the prior

ACL graft and any scar tissue using an arthroscope. Any additional injuries such as meniscal tears are treated arthroscopically as well. The new graft is placed in the correct anatomical position.

Rarely, patients may need additional surgical techniques such as osteotomies. Osteotomies involve cutting of the bone to alleviate any mal-alignment of the extremity. After the surgery, a rehabilitation protocol is again followed aimed towards a full range of motion and return to activities of daily living.