Preoperative Planning

Once a diagnosis of failed reconstruction has been made, a plan should be formulated to address the identified mode of failure. Not all scenarios mandate ACL graft revision. For example, presence of an isolated cyclops lesion generating loss of motion in an otherwise stable knee without tunnel malposition can be treated effectively with arthroscopic debridement. The majority of clinical failures, however, do involve index graft revision. Although a trial of functional bracing may be considered for those patients willing to make significant lifestyle modifications and accept the possibility of meniscal injury with its incumbent risk of accelerated arthrosis, most cases necessitate operative treatment. The patient should be counseled that the results of revision reconstruction are not equivalent to those of index procedures.13 Nevertheless, proper planning and execution should result in a stable construct, and if patient expectations are appropriate, the chance of overall success remains high.

Following careful clinical evaluation as previously outlined, a preoperative checklist (Table 52-2) of key variables can be formulated to help with planning. Graft selection for revision reconstruction remains a controversial issue, and success has been reported with a variety of different allograft and autograft constructs. Consensus does exist, however, that synthetic graft materials are not recommended for either primary or revision ACL reconstruction. The most commonly reported grafts selected for revision reconstruction are bone-patellar tendon-bone (BPTB) autograft, and fresh-frozen BPTB allograft.4 Auto-graft offers more rapid graft tunnel incorporation and avoids risk of disease transmission but may not be available in a revision setting and carries with it the risk of donor site morbidity. Use of allograft, on the other hand, eliminates donor site morbidity. An additional advantage of allograft use is that accompanying bone blocks are often large, a useful feature when attempting to achieve rigid fixation in the context of tunnel dilatation (Fig. 525). Some patients, however, may be unwilling to accept the small, but finite risk of disease transmission with the use of allo-grafts. Commercial tissue banks often use doses of gamma irradiation between 1.5 and 2.5 mrad to treat harvested tissue. While doses in this range are considered to be bactericidal, Smith et al14 showed that active viral replication of human immunodeficiency virus type 1 persisted in culture after doses as high as 5.0 mrad. Such high doses of gamma irradiation, however, may render allograft tissue mechanically unfit for implantation. Fideler et al15 clearly demonstrated a dose-dependent decrease in the biomechanical properties of BPTB allograft following gamma irradiation. With use of 2.0 mrad of gamma irradiation, they observed a 15% reduction in initial bio-mechanical strength when compared to nonirradiated fresh-frozen controls. This reduction increased to as high as 46% when

Table 52-2 Anterior Cruciate Ligament Revision Preoperative Checklist

Preoperative Checklist

Comments

Mode of failure of index procedure

Type of hardware used in index procedure

A selection of screwdrivers and other extraction devices when indicated should be available for hardware removal

Presence of tunnel enlargement

Marked enlargement (>15mm) may require a staged procedure

Presence of concomitant intra-articular pathology

Meniscal tears or focal chondral defects should be addressed at the time of the revision procedure

Presence of angular malalignment

Significant angular malalignment can contribute to index graft failure and should be addressed at the time of the revision procedure

Integrity of secondary stabilizers

Posterolateral corner reconstruction may be required at the time of revision

Revision graft selection

Allograft vs. autograft; irradiated vs. nonirradiated; availability must be confirmed

Revision graft fixation

At least two means (primary and back up) of secure fixation should be available and the surgeon should be facile with each (e.g., interference screw, EndoButton)

Revision tunnel placement

The means of establishing anatomic tunnel position should be decided (e.g., overlapping tunnels, diverging tunnels, two-incision technique)

grafts were exposed to a 4-mrad dose. Use of irradiated versus nonirradiated allograft remains controversial, as does the optimal dose of gamma irradiation in the case of irradiated tissue. Current molecular screening tests, such as reverse-transcriptase polymerase chain reaction and other techniques are highly sensitive, and the surgeon and patient must make a joint, informed decision when it comes to autograft versus allograft and irradiated versus nonirradiated.

Another consideration when using allografts for revision work is the amount of tissue that will be necessary given the size of the patient. When ordering a BPTB allograft, inclusion of the patient's height may help avoid mismatch between the size of graft received and the amount of tissue needed for reconstruction. Finally, quadruple hamstring and quadriceps tendon grafts (allo- and auto-) are also possibilities for revision reconstruction, but experience with these graft selections in the setting of revision surgery is less extensive than that with BPTB grafts.

Figure 52-5 Intraoperative image of a standard bone-patellar tendon-bone allograft after the portion to be used for the reconstruction has been harvested. Ample bone stock remains in the allograft, permitting femoral and tibial bone blocks to be fashioned larger as needed and providing substrate for grafting of bony defects.

Figure 52-5 Intraoperative image of a standard bone-patellar tendon-bone allograft after the portion to be used for the reconstruction has been harvested. Ample bone stock remains in the allograft, permitting femoral and tibial bone blocks to be fashioned larger as needed and providing substrate for grafting of bony defects.

Was this article helpful?

0 0
Cure Tennis Elbow Without Surgery

Cure Tennis Elbow Without Surgery

Everything you wanted to know about. How To Cure Tennis Elbow. Are you an athlete who suffers from tennis elbow? Contrary to popular opinion, most people who suffer from tennis elbow do not even play tennis. They get this condition, which is a torn tendon in the elbow, from the strain of using the same motions with the arm, repeatedly. If you have tennis elbow, you understand how the pain can disrupt your day.

Get My Free Ebook


Post a comment