Knee Ligament Revision

Knee Ligament Revision 2017-08-03T17:17:31+00:00

Although tremendous advances have been achieved in reconstructing the anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), and lateral collateral ligament (LCL), these operations may fail to restore normal knee stability for a variety of reasons. In fact, it is estimated that as many as 10,000 cruciate ligament reconstructions fail each year in the United States alone.

Dr. Frank Noyes and researchers at the Noyes Knee Institute have spent nearly 2 decades studying the causes of failure of knee ligament reconstructions, and the outcome of revision operations using a variety of graft materials. Few institutions in the country have the experience found at the NKI in handling this problem. Our research team has published numerous studies on ACL revision, and the only study on PCL revision to date in the medical literature. Patients benefit from not only the advanced revision operative techniques we offer, but the experience required to identify the factors which caused the original reconstruction to fail.

Why ACL Reconstructions Fail

ACL reconstruction is a popular operation which is performed on over 100,000 patients in the United States each year. Failure of this procedure that results in knee instability and giving-way occurs in 3% to 10% of patients. Therefore, thousands of individuals may require an ACL revision operation each year in the U.S. alone.

Although operative techniques, graft substitutes, and rehabilitation programs continue to improve, ACL reconstructions fail because of many reasons. It is imperative that the reasons for the failure be determined before revision is considered so that appropriate treatment of all of the knee problems can be performed. If the original problems are not corrected, the revision procedure may not be successful.

The reasons ACL procedures fail include (but are not limited to):

  • Use of a graft that is biomechanically inferior to the native ACL
  • Failure of the graft to complete the process of healing, also referred to as ligamentization or revascularization
  • Improper placement or orientation of the graft tunnels, usually in either a vertical or anterior position, which does not replicate normal ACL anatomy
  • Impingement of the graft in the femoral notch due to inadequate notchplasty or graft placement
  • Improper tensioning of the graft before fixation
  • Inadequate graft fixation because of either the fixation device itself or inadequate bone stock of the host bone (known as osteopenia)
  • Failure to correct associated knee ligament ruptures or deficiencies, commonly involving the posterolateral structures
  • Failure to correct a bowed leg condition (known as varus osseous lower limb malalignment)
  • Traumatic reinjury
  • A combination of any of the above factors

Shown below is an x-ray of a patient 1 year after an ACL reconstruction was done with a patellar tendon autograft. The operation failed because the graft tunnels were placed too far anteriorly

Fig1

 

 

Shown below is an x-ray of the same patient that was taken after an ACL revision reconstruction was performed with a quadriceps tendon autograft. The screw in the femur from the first procedure was placed so deeply and away from the new tunnel that id did not require removal.

 

Fig2

 

 

When Failed ACL Reconstructions Require Revision

 

The indications for ACL revision are:

  • Complete failure of a prior ACL procedure as determined by a fully positive pivot-shift test and > 6 mm of increased anterior tibial translation on Lachman or instrumented KT-2000 testing
  • Symptoms or functional limitations with daily or sports activities

 

The contraindications for ACL revision are:

 

  • Partial function of a prior ACL reconstruction
  • No symptoms (pain, swelling, giving-way) in a patient who does not participate in strenuous or high-risk activities
  • Prior joint infection
  • Obesity (body mass index > 30)
  • Bowed legs, where the patient refuses to undergo a high tibial osteotomy before or with the ACL revision reconstruction

 


Fig3

 

  • Severe muscle atrophy
  • Poor patient motivation or expectations
  • Knee arthrofibrosis
  • Deficiency of the posterolateral structures where the patient refuses to undergo an associated posterolateral reconstruction with the ACL revision

Patients who are considering revision reconstruction at the NKI must undergo a comprehensive evaluation by the surgeon that includes a meticulous physical examination; observation of gait during walking to identify problems that require correction before surgery; and analysis of x-ray and MRI films to determine the location and size of the prior graft tunnel, joint narrowing (indicating arthritis), and overall lower limb alignment.

 

Graft Choices for ACL Revision Reconstruction

 

Our first graft choice for ACL revision reconstruction is the patellar tendon autograft. Studies show that this graft appears to have acceptable results in terms of restored knee stability. If the patellar tendon was previously used, then the opposite knee provides an excellent source to obtain the portion of this tendon required for the operation. There does not appear to be a negative effect on patient recovery when the patellar tendon is harvested from the opposite knee. At the NKI, this graft is harvested with a very small (1 inch) incision, the patellar tendon is carefully sutured back together, and the defect created in the patella is filled in with bone obtained during other portions of the operation. These technical aspects of the operation, along with a carefully designed rehabilitation program, reduce graft site pain and enable patients to kneel after a few months.

In patients who will not consider harvest of the patellar tendon from the opposite knee, the quadriceps tendon is a reasonable graft source according to its size and structural properties. Our study showed similar results in restored stability between patients who had a patellar tendon autograft and those who had a quadriceps tendon autograft ACL revision reconstruction.

A semitendinosus-gracilis four-strand (hamstring) autograft may be considered if the tibial and femoral tunnels are not enlarged and if there is no loss of bone stock at the prior tibial or femoral graft sites. In our experience, this is a rare graft option for ACL revision, especially in female athletes who usually have weak hamstring muscles and in whom the harvest of this graft would result in a permanent deficit in hamstring strength.

Allografts have been used in revision ACL cases, but because they have a higher failure rate (compared to autografts), they are considered our last graft option in the majority of ACL revision knees.

Rehabilitation After ACL Revision Reconstruction

For patients who undergo ACL revision without an associated posterolateral reconstruction or high tibial osteotomy at the NKI, the postoperative rehabilitation protocol may be found by clicking here. ACL-Delayed

For patients who undergo ACL revision with an associated posterolateral reconstruction at the NKI, the postoperative rehabilitation protocol may be found by clicking here. Posterolateral Protocol

For patients who undergo ACL revision with a high tibial osteotomy at the NKI, the postoperative rehabilitation protocol may be found by clicking hereHTO Protocol

Results of ACL Revision Reconstruction

The results expected from ACL revision are based on other operative procedures that are required and the condition of the menisci and articular cartilage. Because the results of ACL revision are generally reported to be less favorable compared to those of primary (first-time) procedures, the decision to proceed must be carefully discussed by the surgeon and patient.

The outcome of ACL revision reconstruction is often inferior to primary reconstruction because the majority of patients have other knee problems such as arthritis (deterioration of the articular cartilage), loss of a meniscus, slack or deficient other ligaments, or bowed legs. In our experience, approximately 90% of ACL revision cases have these problems. The goal of the operation in these patients is to alleviate pain and swelling with daily activities and return to low-impact activities in order to maintain an active lifestyle.

ACL reconstruction has favorable results in patients who have pre-existing arthritis; however, we counsel the avoidance of strenuous athletics after surgery to preserve the knee joint for as long as possible.

Patients who do not have arthritis, meniscus damage, bowed legs, or other ligament problems may have results similar to those reported after primary ACL reconstruction. Therefore, we recommend that ACL revision reconstruction be done early in athletically-active individuals or patients involved in strenuous occupations after failure of a prior procedure is detected. We do not recommend a trial of strenuous activity after a failed ACL reconstruction in these cases. This is because reinjuries and knee joint deterioration may occur in a manner similar to that observed in chronic ACL-deficient knees.

Scientifically-Based Evidence For Our Recommendations

Dr. Frank Noyes and researchers at the NKI have published 3 studies on the outcome of ACL revision reconstruction. In these studies, 140 patients who received either a patellar tendon allograft, patellar tendon autograft, or quadriceps tendon autograft were followed between 2 and 7 years after the revision procedure. Approximately 90% had associated problems such as knee arthritis, prior meniscectomy, bowed legs, or other ligament ruptures. The studies were published in the Journal of Bone and Joint Surgery and in the American Journal of Sports Medicine.

The data from these prospective investigations revealed:

  • Similar results existed between patellar tendon autografts and quadriceps tendon autografts for knee stability (80% normal or nearly normal knee stability achieved).
  • Poorer results were found for allografts for knee stability (67% normal or nearly normal knee stability achieved).
  • ACL revision surgery should be performed early after graft failure is detected to avoid further joint damage.
  • All attempts should be made to repair meniscus tears, as loss of this tissue further compounds problems after ACL reconstructions fail.
  • Bowed legs must be treated first with a high tibial osteotomy to correct the malalignment, as failure to do so carries a high likelihood of failure of ACL reconstructions.
  • Associated knee ligament ruptures or deficiencies must be surgically corrected with ACL reconstruction to restore normal kinematics to the knee joint.

Why PCL Reconstructions Fail

While many clinical studies have been published on causes of failure of ACL reconstructions, few have investigated this problem after PCL reconstruction. We conducted the first study at the NKI to determine the most common factors which appeared to produce failure in a series of patients referred to us for revision PCL reconstruction.

We found that PCL reconstructions fail because of many reasons. It is imperative that the reasons for the failure be determined before revision is considered so that appropriate treatment of all of the knee problems may be performed. Failure to address these factors may cause a revision procedure to also fail.

The reasons PCL procedures fail include (but are not limited to):

    • Use of primary suture repair instead of a high strength graft substitute
  • Failure to correct associated knee ligament ruptures or deficiencies, usually involving the posterolateral structures
  • Failure to correct a bowed leg condition (varus osseous lower limb malalignment)
  • Improper placement or orientation of the graft tunnels
  • Traumatic reinjury
  • A combination of any of the above factors

Shown below is an x-ray taken 1 year after a failed PCL and LCL/posterolateral reconstruction. The patient had a bowed leg and severe deficiency of the posterolateral structures. The bowed leg condition was not corrected and this caused both ligament reconstructions to fail.

Fig4

 

 

When Failed PCL Reconstructions Require Revision

 

The indications for PCL revision are:

  • Complete failure of a prior PCL procedure as determined by > 10 mm of increased posterior tibial translation on manual testing or > 8 mm of increased posterior tibial translation on posterior stress x-rays
  • Symptoms or functional limitations with daily or sports activities

 

Fig5

 

The contraindications for PCL revision are:

 

    • Partial function remaining of a prior PCL reconstruction
    • Advanced knee arthritis (significant loss of joint space on x-rays)
    • Prior joint infection
    • Obesity (body mass index > 30)
    • Bowed legs, where the patient refuses to undergo a high tibial osteotomy before or with the PCL revision reconstruction
    • Severe muscle atrophy
    • Poor patient motivation or expectations
  • Knee arthrofibrosis
  • Deficiency of the posterolateral structures where the patient refuses to undergo an associated posterolateral reconstruction with the PCL revision

Graft Choices for PCL Revision Reconstruction

The selection of the appropriate graft for PCL revision reconstruction remains controversial and there are incomplete clinical data to support definitive conclusions. Due to the inconsistent results reported from single-strand grafts, we prefer 2-strand graft constructs. Biomechanical and early clinical studies demonstrate that 2-strand grafts more closely replicate normal PCL behavior during knee motion and functional activities.

There are many different graft options for a 2-strand PCL revision reconstruction. One that we have used at the Noyes Knee Institute is the quadriceps tendon autograft which may be harvested from either from the injured knee or the contralateral knee (if previously harvested). This tendon is quite large and can be split to produce a 2-strand graft that is large enough to be placed through separate tunnels as shown below.

 

Fig6

 

Another valid 2-strand graft option is the use of 2 patellar tendons (either 2 patellar tendon allografts or one allograft and one patellar tendon autograft). This treatment plan is advantageous when a 2-tunnel PCL reconstructive technique will be used, or when other ligament deficiencies exist which require reconstruction.

Rehabilitation After PCL Revision Reconstruction

For patients who undergo PCL revision without an associated posterolateral reconstruction, the postoperative rehabilitation protocol may be found by clicking herePCL

For patients who undergo PCL revision with an associated posterolateral reconstruction, the postoperative rehabilitation protocol may be found by clicking herePosterolateral Protocol

Results of PCL Revision Reconstruction

The results expected from PCL revision are based on other operative procedures that are required, and the condition of the menisci and articular cartilage.

The outcome of PCL revision reconstruction is usually expected to be inferior to primary reconstruction because the majority of patients have other knee problems such as arthritis, loss of a meniscus, slack or deficient other ligaments, or bowed legs. In our experience, 83% of PCL revision cases have these problems. The goal of the operation in these patients is to alleviate pain and swelling with daily activities and return to low-impact activities in order to maintain an active lifestyle.

Patients who do not have arthritis, meniscus damage, bowed legs, or other ligament problems may have results similar to those reported after primary PCL reconstruction. However, further studies are required to determine the outcome of PCL revision based on the presence or absence of other knee-related problems.

Scientifically-Based Evidence For Our Recommendations

Dr. Frank Noyes and researchers at the NKI published the first investigation in the medical literature on the causes of PCL reconstruction failure and the first study on the outcome of PCL revision reconstruction.

In our first investigation, the causes of failure of 52 PCL operations (which had been done in 41 knees) were studied. These patients had been referred to our us for a possible PCL revision operation. A total of 155 prior operative procedures had been done in these 41 knees. The most common causes of failure of the PCL procedures were failure to correct associated deficiency to the posterolateral structures, failure to corrected associated varus malalignment (bowed legs), and use of a suture repair technique instead of a graft substitute. We found that 83% had compounding problems of joint arthritis, prior meniscectomy, other ligament deficiencies, or varus malalignment. Only 54% were candidates for PCL reconstruction, as others had either severe joint damage or declined further operations.

Due to the salvage nature of many of these knees, we concluded that a greater emphasis is warranted on primary PCL reconstructions in terms of correction of associated ligament ruptures and varus malalignment, and in achieving proper placement of the graft tunnels. Another finding was a high failure rate of prior posterolateral procedures, leading to the recommendation for an anatomic graft replacement of the fibular collateral ligament and popliteus-tendon-muscle unit when required.

In our second investigation, the outcome of 2-strand PCL quadriceps tendon revision reconstruction was studied in a small series of knees followed from 2 to 7 years postoperatively. Other knee ligament reconstructions were required in 40% of the knees and in 20%, a high tibial osteotomy was done first to correct bowed legs.

Improvement was noted in 80% for pain and in 87% for the patient perception of the overall knee condition. However, only 53% returned to light sports without problems. Adequate posterior knee stability was restored in 87%. The results were believed to be reasonable in the complex group of patients.

For further information on these issues, see our eBooks:

ACL Injury: Everything You Need to Know to Make the Right Treatment Decision

PCL and Posterolateral Knee Ligament Injuries: Everything You Need to Know to Make the Right Treatment Decision