DEFINITION

Anterior cruciate ligament (ACL) injuries result in a disruption of the fibers of this ligament and an ACL-deficient knee.

Although most injuries are complete, partial injuries have been described. In our practice, partial injuries

—defined as an asymmetric Lachman test (or 3 to 4 mm of asymmetry on KT-1000 testing)1 with a negative pivot shift test during examination under anesthesia or a one-bundle ACL disruption seen arthroscopically—are rare.

The key point in determining how to treat partial injuries is to determine whether functional stability of the ACL has been maintained.

 

 

ANATOMY

 

The ACL is about 33 mm long and 11 mm in diameter.10

 

The tibial insertion has a broad, irregular diamond shape and is immediately anterior and adjacent to the medial tibial eminence.

 

The femoral attachment of the ligament is a semicircular area on the posteromedial aspect of the lateral femoral condyle.

 

It extends from the 9 o'clock position to the 11 o'clock position with the knee at 90 degrees flexion (right knee).

 

The ACL is composed of two “bundles”—the anteromedial (AM) portion, which is tight in flexion, and the posterolateral (PL) portion, which is tight in extension. The AM bundle functions more to control stability in the anteroposterior (AP) direction, whereas the PL bundle contributes significantly to rotational stability. It is composed of 90% type I collagen; the remaining collagen is predominantly type III.

 

The main blood supply for the ACL is the middle geniculate artery.

 

Mechanoreceptor nerve endings have been identified within the ACL and are thought to have a proprioceptive role.

 

PATHOGENESIS

 

ACL injuries occur frequently in sports that involve running, jumping, and cutting movements. They can occur without contact when the foot is anchored to the playing surface—usually by way of cleats or a rubber sole— and the body rotates beyond the tolerance of the ligament as the knee buckles. They also occur commonly when landing after a jump (untrained female athletes may land in valgus and extension).

 

Combined ACL, medial collateral ligament (MCL), and meniscal injuries have been referred to as the unhappy triad.17 Although the original triad included medial meniscal injuries, which are more common in chronic ACL

injuries, lateral meniscal injuries are actually more common in acute ACL injuries (especially in skiers).4

 

NATURAL HISTORY

 

Researchers from Kaiser Permanente in Southern California, including Donald Fithian8 and the late Dale

Daniel,7 have done much to contribute to our knowledge of the natural history of the ACL-injured knee. From their work, we recognize that patients with a high level of participation in jumping or cutting sports and significant side-to-side differences (>5 mm) on KT-1000 arthrometer measurements are at high risk for recurrent injury without ACL reconstruction.

 

Unfortunately, these same researchers have shown an increased incidence of arthritis in the surgically reconstructed ACL group.7,8

 

The difficulty with these and other studies is that multiple variables are involved, making comparisons difficult and possibly inaccurate.16

 

It is clear from the literature that the incidence of meniscal tears and chondral injury can be reduced with ACL reconstruction.

 

Advocates of double-bundle ACL reconstruction propose that the incidence of arthritis may be reduced with this technique but that theory has yet to be proven clinically.

 

PATIENT HISTORY AND PHYSICAL FINDINGS

 

Patient history may include the following:

 

 

Patients may describe a noncontact pivoting injury, typically involving a change of direction or deceleration maneuver.

 

Patients often recall hearing or feeling a “pop” and will develop an acute or subacute effusion (ie, “swells up like a balloon”).

 

In most cases, the athlete will not be able to return to play and may need assistance to leave the field or slope (we have termed the latter a positive ski patrol sign).

 

Physical examination methods include the following:

 

 

Effusion: About 70% of acute hemarthrosis cases represent ACL tears.7

 

Range of motion (ROM): Loss of extension may be a result of a displaced bucket-handle meniscal tear or arthrofibrosis (stiff knee). Loss of flexion may be related to a knee effusion.

 

The Lachman test20 is highly sensitive for ACL deficiency. The patient must relax for this examination, and effusion or a displaced meniscal tear may give a false end point.

 

The anterior drawer test is poorly sensitive and outdated but is helpful to rule out a posterior cruciate ligament (PCL) injury.

 

The pivot shift test3 is difficult to perform in the clinic setting but is an especially helpful and sensitive test during examination under anesthesia.

 

 

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A complete examination of the knee also should include evaluation of associated injuries and ruling out differential diagnoses, including (but not limited to) the following:

 

 

Meniscal tears: Joint line tenderness, pain or popping with provocative maneuvers (eg, McMurray, Apley

compression, duck walk), and loss of full extension may be present.

 

PCL injury: A “pseudo-Lachman” may be appreciated if the PCL is present, and the unwary examiner may falsely attribute this to an ACL injury. The key is the starting point on the drawer examination. The tibial step-off in PCL-injured knees will be absent, or the tibia may actually be displaced (or be displaceable) posteriorly, signifying a PCL injury.

 

Posterolateral corner (PLC) injury: Injury to the popliteus, popliteofibular ligament, biceps, iliotibial band, or posterior capsule will result in external rotation asymmetry (dial test), a positive PL drawer test, and external rotation recurvatum.

 

Collateral ligament injury: MCL injuries are recognized as opening with valgus force and lateral collateral ligament (LCL) injuries open with varus stress. These examinations are tested in both 0 and 30 degrees of knee flexion. Opening to valgus or varus stress in 0 degree (ie, full extension) signifies a more severe injury, usually involving one or both cruciate ligaments.

 

Patellar instability: Localized tenderness or instability with apprehension testing is essential to rule out a patellar dislocation that reduced spontaneously. This type of injury also can cause an acute knee effusion and can be easily confused with an acute ACL injury.

 

IMAGING AND OTHER DIAGNOSTIC STUDIES

 

Plain radiographs, including AP, lateral, and patellar views, should be obtained to rule out bony avulsion fractures or associated injuries.

 

A small avulsion fracture off the lateral tibial plateau (FIG 1A) represents a lateral capsular avulsion (Segond sign) and is highly associated with an ACL injury. It is very specific but not sensitive.

 

Flexion weight-bearing radiographs are important in older or posttraumatic patients to rule out associated osteoarthritis.

 

 

Long-leg, hip-to-ankle radiographs must be obtained in patients with varus or valgus malalignment. An osteotomy should be performed before ACL reconstruction in select cases.

 

Magnetic resonance imaging (MRI) is highly sensitive and specific in diagnosing ACL tears as well as associated injuries.

 

 

 

FIG 1 • A. Segond (lateral capsular) sign (white arrow). A small avulsion fracture in this area is highly associated with an ACL injury. B. MRI of ACL-injured knee with associated bone bruises (black arrows).

These impaction injuries are in the classic locations—the most lateral aspect of the middle third of the lateral femoral condyle and the posterior aspect of the tibia.

 

 

Bone contusions, or bruises, also may be detected in the midlateral potion of the lateral femoral condyle (near the sulcus terminalis) and the posterior tibial plateau (FIG 1B).

 

DIFFERENTIAL DIAGNOSIS

 

 

 

Meniscal tear Osteochondral injury Contusion

 

Patellar dislocation

 

Other ligament/capsular injury (eg, MCL, LCL, PLC, multiple ligament injury)

 

NONOPERATIVE MANAGEMENT

 

Although nonoperative management is controversial, patients with less laxity and those who are less involved with high-level pivoting sports may be treated nonoperatively.9

 

Nonoperative treatment is done in three phases over a period of about 3 months.

 

In the initial phase, emphasis is placed on regaining full motion, controlling effusion, and maintaining quadriceps tone. (This is appropriate for patients who are surgical candidates as well.)

 

 

In the second phase, quadriceps and hamstring strengthening is emphasized. In the third and final phase, sport-specific rehabilitation is accomplished.

 

Patients may attempt to return to sports after their effusion has completely resolved, they have full ROM, their quadriceps tone and strength have been restored (isokinetic testing is helpful), and they have no residual symptoms of instability (functional testing is helpful).

 

SURGICAL MANAGEMENT

Preoperative Planning

 

All imaging studies are reviewed.

 

Plain radiographs should be reviewed for fractures, loose bodies, patellar height and alignment, and the presence of any hardware (from previous procedures) or foreign bodies.

 

Associated fractures, meniscal tears, articular cartilage lesions, and multiple ligament injuries should be addressed concurrently.

 

Examination under anesthesia should be accomplished prior to positioning.

 

Lachman, pivot shift, varus/valgus, and dial testing should be included in the examination under anesthesia.

 

 

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FIG 2 • Positioning for ACL reconstruction. The knee is placed into a foot holder with a tray attached to the operative table to control the flexion angle of the knee. The knee should be able to be flexed beyond 90 degrees to allow for proper femoral tunnel drilling technique. If using a hamstring autograft for reconstruction, the surgeon may consider including the contralateral leg in the operative field for the potential of bilateral tendon harvest if needed.

 

Positioning

 

Although some surgeons prefer to perform ACL reconstruction with the patient's operative knee in a knee holder with the foot of the bed dropped, we prefer to keep the patient supine with the foot of the table up and a post on the lateral side (FIG 2).

 

In patients electing for a hamstring autograft reconstruction technique, we routinely prep both lower extremities for potential bilateral graft harvest.

 

 

Table 1 Anterior Cruciate Ligament Graft Choice Indications

 

Patellar tendon

 

Football players Gymnasts Sprinters

Ballet dancers

Martial arts participants Patients with systemic laxity

Revision of prior hamstring grafts

 

Hamstring

 

Jumping sport athletes Clergy, carpenters Older patients

Those with prior anterior knee pain Those with patellar chondrosis Those with narrow patellar tendons

Revision of prior patellar tendon grafts

 

 

Approach

 

The approach depends on graft choice.

 

There are two gold standards for ACL grafts—bone-patellar tendon-bone autograft and four-strand semitendinosus gracilis (hamstring) autograft. We use both patellar tendon and hamstring grafts and have found that certain parameters are helpful in determining graft choice (Table 1).

 

Other graft choices include quadriceps tendon autograft and a variety of allografts. Although these grafts may be useful in certain cases, they are not popular choices for most surgeons. Recent studies have suggested a

slightly higher failure rate with the use of allograft, particularly in younger and more active patients.12

 

After the graft is selected, the procedure involves arthroscopic diagnosis and repair of pathology, tibial and femoral tunnel placement, graft passage and fixation, and wound closure.

 

TECHNIQUES

• Patellar Tendon Graft Harvesting

Patellar tendon grafts (TECH FIG 1) are harvested through a 5- to 7-cm paramedian incision. Saphenous nerve branches are protected if identified.

The paratenon is incised vertically and reflected off the underlying tendon.

 

 

 

 

TECH FIG 1 • Patellar tendon graft harvesting. A. Exposure of the patellar tendon and paratenon. B. The middle third (˜10 mm) of the patellar tendon is measured. (continued)

 

 

The central third of the tendon (typically 10 mm) is harvested, with care taken not to cut across the longitudinal fibers of the tendon.

 

Bone blocks (approximately 25 mm long) are obtained using a micro-oscillating saw.

 

Care is taken to saw no deeper than 10 mm, particularly on the patellar side, to avoid an iatrogenic fracture.

 

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TECH FIG 1 • (continued) C. Vertical incisions are made, with care taken not to transect any of the longitudinal fibers of the tendon. D. After the tendon is excised, bone blocks are made on either end.

 

 

Some surgeons advocate drilling the corners of the graft before the graft is harvested with an osteotome (which should be used gently and only “levered” from the top and not the sides).

 

Patellar bone block harvest can be facilitated by placing the knee in an extended position to allow mobilization of the skin incision proximally.

 

The tibial bone block can be either more rectangular or more trapezoidal in cross-section.

 

The patellar bone block should be more triangular in crosssection to avoid injury to the patella.

 

The bone blocks are removed using a curved osteotome (again, being careful on the patellar side) and taken to the back table for preparation.

 

A rongeur or burr is used to fashion the bone blocks so that they will fit through an appropriately sized tunnel. Compression pliers can also be useful.

 

With retraction, the lower portion of the incision can be used to prepare the tibial tunnel.

 

If the tendon is harvested at the beginning of the procedure, arthroscopic portals can be made through the incision.

• Hamstring Tendon Graft Harvesting

   

  Hamstring grafts (TECH FIG 2) are harvested through a 2- to 3-cm paramedian incision centered at the level of the tibial tubercle, approximately 6 cm below the medial joint line.

   

  The sartorial fascia is exposed, and the tendons are palpated.

   

  The tendons insert in an oblique fashion and are more horizontal than vertical.

   

  The gracilis tendon insertion is superior to the semitendinosus tendon insertion, but both tendons converge at the pes anserine.

   

   

   

  TECH FIG 2 • Hamstring graft harvesting. A. The gracilis (top) and semitendinosus (bottom) tendons are isolated by dissecting under the sartorial fascia. B. Whipstitches are placed in the tendons prior to detaching them. C. The tendons are freed from any attachments using blunt dissection and scissors. D. A tendon stripper is used to harvest the tendons. The tendinous slip that was cut would have prevented the stripper from passing unless it was first released.

   

   

  It is necessary to reflect the overlying sartorial fascia that covers both tendons.

   

  Tendon identification may be facilitated by placing a right angle clamp deep to the sartorial fascia and spreading obliquely in line with the tendons.

   

  The tendons can alternatively be exposed from their deep side if their insertions are sharply reflected off the tibia.

   

   

   

  Once the tendons are identified, a whipstitch is placed in them near their insertions for mobilization. Blunt dissection and palpation are essential in mobilizing the tendons.

   

   

  Both tendons must be mobilized and all tendinous slips freed.

   

  The semitendinosus will have one or more large bands that attach to the medial head of the gastrocnemius. These must be incised before a tendon stripper is used, or the tendon will be inadvertently cut at this location.

   

  After harvesting, the tendons are prepared on the back table.

   

  P.460

   

  Muscle fibers are removed from the tendons using a curette or elevator, a whipstitch is placed in the free end, and the tendons are tensioned using a commercially available graft board.

   

   

  The grafts are folded in half and the diameter of the four-strand graft measured before tensioning. The harvest incision can easily be used for tibial tunnel placement.

   

  Standard arthroscopic portals are made through the skin at the level of the joint.

   

  Longer semitendinosus tendons can sometimes be tripled, creating a five-strand construct (when added to the double construct). This has been termed the Mach 5 graft by Dr. Charles Brown.11

   

  If a graft diameter less than 8 mm is obtained, a decision is made to augment the autograft with allograft tendon tissue or to perform a harvest procedure on the contralateral hamstrings for additional

  supplementation.13

• Arthroscopy

   

   

  Diagnostic arthroscopy is completed, and all pathology is identified. Meniscal tears are repaired if possible.

   

   

  Articular cartilage lesions are addressed. Loose bodies are identified and removed.

   

  The ACL is visualized and, if torn, is débrided with baskets and a shaver. We prefer to leave a small amount of the femoral footprint attached to assist in identifying proper tunnel location.

   

   

   

  TECH FIG 3 • A. Remnant ACL tissue is débrided with a combination of arthroscopic shaver, scissors, and electrocautery. A notchplasty is rarely needed to aid in visualization. B. The torn ACL. C. Débridement of footprint with the electrocautery device. D. Remnant ACL footprint after débridement of tissue.

   

   

  The tibial footprint of the ACL and the “over-the-top” position in the back of the notch are cleared of all soft tissue (TECH FIG 3).

   

  Although most surgeons no longer perform an aggressive notchplasty, it is important to clear enough soft tissue and bone to identify all landmarks and to ensure that the graft will not be impinged on.

   

  It also is important to ensure that the roof of the notch will not impinge on the graft. (This is more important in hamstring reconstructions because the anterior portion of the graft may be more easily impinged.)

   

  P.461

• Femoral Tunnel Placement

   

  Our preferred technique has evolved from a traditional transtibial femoral tunnel to a tunnel drilled through an accessory medial portal.

   

  Under direct visualization from the medial portal, an accessory medial portal is established in a position that allows a direct line to the anatomic midpoint in the femoral insertion.

   

  Our preferred tunnel position is located at the junction of the third and fourth quadrant of the femoral footprint, viewing anterior to posterior, with the knee in 90 degrees flexion, approximately 10 to 12 mm above the inferior margin of the lateral femoral condyle.

   

  A Beath pin is introduced through the accessory medial portal, and after the insertion point is confirmed, the knee is hyperflexed and the pin is driven through the bone and out the lateral thigh. Because it is difficult to understand proper orientation with the knee hyperflexed, we encourage surgeons to “trust” the location chosen when the knee was in 90 degrees of flexion.

   

  Other options for femoral tunnel placement include the use of an offset guide, with care taken to retain a

  2 to 3 mm posterior wall following drilling. (A 10-mm tunnel should be made with a 7- to 8-mm offset guide because the guide is used to place a guidewire for the center of the tunnel and the radius of a 10-mm drill is 5 mm.)

   

   

   

  TECH FIG 4 • A. Femoral tunnel position is marked at the junction of the third and fourth quadrant of the femoral footprint, viewing anterior to posterior through the medial portal, with the knee in 90 degrees flexion, approximately 10 to 12 mm above the inferior margin of the lateral femoral condyle. B. Alternative option with femoral over-the-top guide in correct position. C,D. Partially threaded acorn drill bit introduced through accessory medial portal with protective skid prior to drilling femoral tunnel. E. The femoral tunnel is drilled to a depth of approximately 30 mm for a patellar tendon graft. F. View after drilling of tunnel, showing intact posterior wall.

   

   

  The femoral tunnel is drilled to a depth of approximately 30 mm for a patellar tendon graft and to within 5 to 8 mm of the far cortex for a hamstring graft (depending on fixation used).

   

  It is essential to protect the medial femoral condyle during tunnel preparation. We use a skid that is placed between the drill and the cartilage surface. For drilling, we use a partially threaded drill bit (TECH FIG 4).

   

  Depending on the surgeon's choice for femoral graft fixation, additional tunnel preparation may be necessary.

   

  For EndoButton (Smith & Nephew, Andover, MA) fixation, a 4.5-mm tunnel is drilled through the far cortex.

   

  For TransFix (Arthrex, Naples, FL), Bone Mulch (Arthrotek, Warsaw, IN), Rigid Fix (DePuy Mitek, Norwood, MA), and other similar fixation systems, transverse pilot holes are created from lateral to medial.

   

  For InterFix (DePuy Mitek), the tunnel is drilled approximately 30 mm deep and the device is inserted in the center of the bundles. We have found that a 0-Vicryl stitch can be wrapped around the graft to avoid graft impingement.

   

  P.462

• Tibial Tunnel Placement

   

   

  A commercially available guide is used to place a guidewire for the tibial tunnel. The intra-articular landmarks for the tibial tunnel are as follows (TECH FIG 5):

   

  Center of the ACL footprint

   

  Just anterior to the medial eminence

   

  Along a line extended from the posterior border of the anterior horn of the lateral meniscus

   

  The extra-articular portion of the guide should be positioned midway between the tibial tubercle and the

  posteromedial aspect of the tibia.6 However, for independent femoral drilling, it can also be placed closer to the tibial tubercle.

   

  For patellar tendon reconstructions, we have previously used the “N + 7 rule”15 to select the angle of the

  guide and checked based on the “N + 2 rule.”18 That is, the guide is provisionally set at an angle that is 7 degrees more than the tendon length (in millimeter) between the bone blocks, and the distance is checked on the plunger for the guide—it should be 2 mm longer than the tendon length. With our current technique and landmarks, we now use the “N + 10” rule (unpublished data).

   

   

   

  TECH FIG 5 • A. Tibial targeting guide. B. Arthroscopic view of ACL tibial tunnel guide pin placement. C. Fluted reamer showing collected bone graft following tibial tunnel drilling. D. Tibial pin placement usually is performed at an angle 10 degrees greater than the graft-soft tissue construct.

   

  The guide is set between 45 and 50 degrees for hamstring grafts.

   

  Once the guidewire is placed and checked, a cannulated drill is used to complete the tibial tunnel.

   

  We use a fully threaded drill bit and save the bone graft that collects in the flutes of the drill to fill the patellar defect (it usually is discarded for hamstring graft reconstructions).

   

  The PCL is protected with a curette during final tunnel drilling.

   

   

  The back edge of the tibial tunnel is rasped to keep the graft from being abraded.

   

• Final Tunnel Placement

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  Prior to drilling, femoral and tibial guide pin placement can be checked (TECH FIG 6). We have found that the tibial tunnel should be just under 40% of the AP distance (and not 44% as has been referenced) and that the femoral tunnel should be at the junction of the third and fourth quadrants and below Blumensaat line on the lateral radiograph.

   

   

   

  TECH FIG 6 • Fluoroscopic lateral view, confirming guide pin placement on both femur and tibia prior to tunnel drilling.

• Graft Passage and Fixation

   

  The Beath needle placed during femoral tunnel preparation is used to pull a passing suture through the tunnel, quadriceps muscle, and skin. An arthroscopic grasper is then used to pull the passing suture

  down through the tibial tunnel.

   

  Sutures from the graft or fixation device are pulled through the tunnels and outside the thigh.

   

   

   

  TECH FIG 7 • A. Schematic shows passing stitch coming through accessory medial portal and femoral tunnel. This is then retrieved through the tibial tunnel. B. Schematic shows graft fixation with interference screw for bone-tendon-bone graft option. (continued)

   

   

  The graft is pulled into both tunnels and fixed with an interference screw or a fixation device of the surgeon's choice.

   

  Once the femoral side is fixed, the knee is cycled through the complete ROM, and the graft is tensioned.

   

  The tibial side is then fixed in extension with an interference screw or secured to the tibia with a screw and washer or staple (TECH FIG 7).

   

  The graft is probed and inspected before wound closure is performed.

   

   

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  TECH FIG 7 • (continued) C. Arthroscopic image shows preferred bone plug orientation within femoral tunnel. D. Arthroscopic image shows final graft fixation on femoral tunnel.

• Wound Closure

   

  The wounds are closed in layers.

   

  Bone graft from the drill bit or bone block preparation is packed into the patellar defect, and the paratenon is closed for patellar tendon graft cases.

   

   

  The sartorial fascia is closed for hamstring graft cases. Subcutaneous tissue and skin are closed in standard fashion.

• Special Considerations

 

Revision ACL

 

In the setting of a previously reconstructed ACL, the surgeon must consider additional factors affecting the reconstruction technique (TECH FIG 8 A-E).

 

If a previous tunnel is in the correct anatomic position, it may be reused, or if tunnel expansion has occurred, bone grafting with a dowel of allograft bone should be completed, with a second stage

procedure in 3 to 6 months for definitive reconstruction.19

 

If a previous tunnel is out of the anatomic location for the planned revision tunnel, the surgeon may again use bone grafting but may proceed with a single-staged reconstruction procedure.

 

Single-bundle augmentation of partial ACL rupture

 

In rare cases, a careful examination under anesthesia and diagnostic arthroscopy may reveal a partially torn ACL. This may present with either an intact PL bundle with a torn AM bundle or an intact AM bundle and a torn PL bundle.

 

Although technically challenging, it may be reasonable to preserve the intact bundle and proceed with a singlebundle augmentation of the damaged portion alone.

 

Surgeons must exercise caution when taking this approach that the remaining bundle does not display any internal hemorrhaging or signs of functional elongation.

 

Pediatric ACL

 

ACL reconstruction in the skeletally immature patient must respect the remaining physeal growth on both the distal femur and proximal tibia (TECH FIG 8 F,G).

 

Our preferred approach for reconstruction is an all epiphyseal technique for the femoral tunnel and a physealcrossing technique on the tibial tunnel. Attention should be given to place a more vertically and

centrally oriented tibial tunnel to minimize the physeal cross-section.14

 

It is imperative to avoid the use of bone-based graft choices if crossing the physis in a skeletally immature patient to minimize the risk of physeal bar formation.

 

Tibial fixation should be kept in the distal portion of the tunnel, with care taken to avoid crossing the physis.

 

 

 

TECH FIG 8 • A. If the previous tunnel is in a nonanatomic position, the new tunnel can be placed using normal technique, and a bone dowel can be positioned in the prior tunnel after hardware removal. (continued)

 

 

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TECH FIG 8 • (continued) B-D. If the previous tunnel is adjacent to the anatomic position, existing hardware is removed, a bone dowel is inserted and the patient is reconstructed in two stages after bony healing. E. If the previous tunnel is in the anatomic position, the hardware is removed and a single-stage revision is completed provided that there is no excessive tunnel widening present. (continued)

 

 

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TECH FIG 8 • (continued) F. Pediatric ACL: femoral tunnel position below the physis on femoral side and vertical and centrally oriented transphyseal tunnel on tibia. Tibial fixation is placed distal to the physis. G. Lateral tunnel landmarks. Femoral tunnel is posterior to LCL insertion.

 

 

 

PEARLS AND PITFALLS
	Indications ▪ A complete history and physical examination should be performed. A diagnostic arthroscopy can be used to confirm the diagnosis, if any question remains, prior to graft harvest. Care must be taken to address associated pathology.     Graft ▪ Extreme care should be taken when harvesting and preparing grafts. management ▪ Patellar bone blocks should be carefully harvested to avoid fracture. The hamstring must be completely freed prior to harvesting. The graft should be secured at all times and handled carefully.     Tunnel ▪ Anterior tunnel placement is responsible for most ACL reconstruction failures. placement ▪ Careful tunnel placement should be routine. Intraoperative radiographs can be obtained to check tunnel locations before drilling.

 

 

 

	Guide pin ▪ Knee flexion must not change, following guide pin placement. breakage ▪ A few degrees of flexion may result in the guidewire bending and shearing by the drill.     Fixation ▪ Interference screws must be inserted along the path of the tunnel to avoid problems divergence. The flexible guidewire should be place on the bony side of the graft and should be parallel to the graft. Commercially available devices can be used to assist in guidewire placement. For the femoral tunnel, the surgeon should hyperflex the knee and drop his or her hand toward the tibia while inserting the interference screw. For the tibial tunnel, the screw is started more parallel to the tibial plateau and then more vertically, after the threads gain purchase. Intraoperative radiographs should be taken so that problems may be recognized and fixed before leaving the operating room.

 

 

 

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POSTOPERATIVE CARE

 

Radiographs are evaluated to ensure that graft placement and fixation are appropriate (FIG 3).

 

 

Some surgeons place the patient in a knee immobilizer or a hinged brace, but we have found that this may restrict their motion and does not provide any benefit.

 

Early ROM (especially extension) is emphasized.

 

It is important that a pillow be placed under the heel (not under the knee, which is more comfortable), beginning in the recovery room.

 

Closed-chain rehabilitation (beginning with a stationary cycle) is emphasized in the early postoperative course.

 

Running typically is delayed until 3 or 4 months postoperatively, and most athletes can return to their sport by 6 months.

 

OUTCOMES

With appropriate indications and surgical technique, success rates for ACL reconstruction are on the order of 90% to 95%.

In one study, 96% of patients had KT-1000 side-to-side differences2 of less than 5 mm. Comparisons between patellar tendon and hamstring reconstruction have yielded equivalent results.

Some studies suggest that hamstring grafts may have slightly increased laxity (1 to 2 mm) compared with patellar grafts.

Other studies have cited an increased incidence of anterior knee pain following ACL reconstruction with patellar tendon grafts.

 

 

 

 

FIG 3 • Postoperative posteroanterior (PA) (A) and lateral (B) radiographs of ACL reconstruction with bone-patellar tendon-bone autograft.

 

COMPLICATIONS

Intraoperative graft mishandling5 Graft failure or rupture

Patellar fracture

Deep venous thrombosis Infection

Loss of motion

Tunnel enlargement (a later complication)21

 

 

 

REFERENCES

1. Bach BR Jr, Nho SJ. Anterior cruciate ligament: diagnosis and decision making. In: Miller MD, Cole BJ, eds. Textbook of Arthroscopy. Philadelphia: Elsevier, 2004:633-643.

    

    

2. Bach BR Jr, Tradonsky S, Bojchuk J, et al. Arthroscopically assisted anterior cruciate ligament reconstruction using patellar tendon autograft. Five to nine year follow-up evaluation. Am J Sports Med 1998;26:20-29.

    

    

3. Bach BR Jr, Warren RF, Wickiewicz TL. The pivot shift phenomenon: results and a description of a modified clinical test for anterior cruciate ligament insufficiency. Am J Sports Med 1988;16:571-576.

    

    

4. Barber FA. What is the terrible triad? Arthroscopy 1992;8(1):19-22.

    

    

5. Cain EL Jr, Gillogly SD, Andrews JR. Management of intraoperative complications associated with autogenous patellar tendon graft anterior cruciate ligament reconstruction. Instr Course Lect 2003;52:359-367.

    

    

6. Chhabra A, Diduch DR, Blessey PB, et al. Recreating an acceptable angle of the tibial tunnel in the coronal plane in ACL reconstruction using external landmarks. Arthroscopy 2004;20:328-330.

    

    

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