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ACL Reconstruction - BTB Graft

Planning

B

Preoperative Plan

1

Radiographic and MRI assessment

  • diagnose ACL tear and any other pathology that will be addressed during the ACL reconstruction.
  • ensure that the patella is appropriate to harvest a graft.
  • asses for physeal closure on femur and tibia.

2

Discuss options with the patient

  • discuss graft options with the patient.
  • graft options other than BTB are usually recommended for patients with professions requiring prolonged kneeling such as clergy, roofing, and flooring workers.

3

Execute surgical walkthrough

  • describe key steps of the operation verbally to attending prior to beginning of case.
  • description of potential complications and steps to avoid them
C

Room Preparation

1

Surgical Instrumentation

  • arthroscopy tower and ACL tray

2

Room setup and Equipment

  • operative table, choice of using leg post, leg holder or neither.

3

Exam under anesthesia

  • once the patient is under anesthesia
  • examine the operative and non-operative leg.
  • assess range of motion, Lachman, Pivot Shift, LCL, MCL, and pulse exam.

4

Patient positioning

  • place patient supine on the table.
  • thigh tourniquet is often used at least during the graft harvest
  • if using a leg post, position the patient's heels at the edge of the bed and shift the patient closer to the side of the post. Ensure that the post is in the proper location to produce a valgus stress
  • if using a leg holder, the end of the bed is often lowered allowing the operative leg to flex to 90 degrees free. The non-operative leg is either placed in a well leg holder or on padding
  • the operative leg must be able to flex to at least 120 degrees. If using a leg holder, a non-sterile assistant will need to unlock the top of the holder when high flexion is needed

Technique

D

Graft Harvest

1

Mark the incision

  • mark the incision to be centered over the patella tendon or on the medial border of the patella tendon approximately 5-7 cm extending from the distal pole of the patella to the proximal portion of the tibial tubercle
  • the tibial tunnel can be created through a the same skin incision with retraction if the initial incision is on the medial border of the patella tendon
  • a separate skin incision can be created if the initial incision is midline
  • this skin marking can be created now prior to arthroscopy in case soft tissue swelling causes distortion of the tissue
  • the arthroscopy portals can be placed either within the same incision or through separate skin incisions

2

Make the skin incision

  • dissect down to the level of the patellar tendon paratenon, but not through it
  • create tissue flaps at the layer superficial to the paratenon to be able to visualize the medial and lateral border of the patella tendon as well as the proximal tibia and distal patella

3

Incise the paratenon at the midline

  • the paratenon is incised in the midline of the tendon, and reflected off the underlying tendon
  • care is taken to establish a viable layer for later closure

4

Choose tendon width and incise tendon

  • the knee is flexed to 90 degrees to put the tendon under tension
  • the central third of the patella tendon (typically 10 mm) is incised with either a double or single bladed scalpel

5

Harvest bone blocks

  • bone blocks are often approximately 20-25 mm in length and the same width as the chosen tendon width (typically 10 mm)
  • with the knee now in extension, the bone blocks are harvested with a micro oscillating saw and a small 5 mm curved osteotome
  • often the tibial side is harvested first, then gentle distal traction is applied to the graft to expose the more mobile patella for bony harvest
  • the oscillating saw is brought to a depth of approximately 10 mm, particularly on the patella side to avoid an iatrogenic fracture
  • the tibial bone block can be more rectangle or trapezoidal in cross section
  • the patella bone block should be more triangular in cross section to avoid injury to the patella
  • once the cuts are completed on the respected bone, the curved osteotome is used to carefully release the the bone from the harvest site
  • aggressive osteotome use is not recommended due to risk of fracture of the bone block or surrounding bone
E

Graft Preparation

1

Bone plug contouring

  • shape the bone plugs to fit into a 10 mm tunnel
  • reduce the excess bone to morsels to later be used for bone grafting of the patellar defect

2

Assess the harvested graft

  • measure the total length, bony lengths and widths, and tendon length

3

Fashion the bone to fit appropriately sized tunnels

  • rongeur, bone crimp, mico oscillating saw, or burr can all be used to fashion the graft to the appropriate size

4

Make drill holes

  • drill holes in the bone blocks to accept sutures for passing and tensioning the graft

5

Mark the graft

  • mark the bone tendon junction with a sterile marker to allow for visualization during graft passage
F

Diagnostic Arthroscopy

1

Portals

  • anterolateral
  • an 11 blade is used to create the portal at a 45 degree angle into the joint just lateral to the patella tendon and just inferior to the distal pole of the patella
  • insert the blunt trocar at the same angle as incision
  • anteromedial
  • often created under direct visualization once the medial compartment is entered
  • place knee in approximately 30 degrees of flexion with valgus moment applied. Use a spinal needle to assess direction and appropriate superior/inferior direction visualizing the entrance from the lateral viewing portal
  • the medial portal should be located just superior to the medial meniscus and able to provide access to the anatomic ACL footprint on the femur as well and the medial meniscal root if needed

2

Diagnostic

  • visualize
  • Suprapatellar pouch
  • undersurface of the patella and trochlear groove
  • lateral and medial gutters
  • medial compartment
  • visualize the medial femoral condyle and follow it while bringing the knee into slight flexion and applying a valgus stress to the knee as you go into the medial compartment
  • the foot will be positioned on your opposite hip for control
  • medial meniscus, medial femoral condyle, and medial tibial plateau
  • once the anteriomedial portal is created, a probe is used to assess the medial meniscus and cartilage
  • intercondylar notch – ACL/PCL
  • use probe to assess the ACL and PCL
  • lateral compartment
  • the surgeon can bring the leg into a figure-4 position or place the operative limb on the surgeon's hip to create a varus stress and flexion to the knee to enter the lateral compartment
  • lateral meniscus, lateral femoral condyle, and lateral tibial plateau
  • a probe is used to assess the lateral meniscus and cartilage
G

Tunnel Placement and Site Preparation

1

Debride the ACL footprint

  • the ACL remnant is removed from the notch usually with a shaver and/or a radiofrequency ablation device while noting the anatomic footprint on the femoral and tibial side for later reconstruction
  • leave a small portion of the footprint intact to permit proper identification of the ACL origin and insertion
  • care is taken not to injure the PCL

2

Notchplasty

  • a notchplasty can be performed if needed using a large shaver or a burr

3

Mark the femoral footprint

  • mark the center of the femoral footprint with an awl or curette with the knee flexed to 90 degrees
  • the anatomic footprint is used as a guide.
  • this position is typically 6-7 mm anterior to the back wall to allow 1-2 mm of back wall after tunnel reaming
  • confirm the position of the mark by switching the 30 degree scope to the anteromedial portal, then switch the scope back to the anterolateral portal for viewing

4

Drilling the femoral tunnel

  • the surgeon can choose between an inside-out technique or an outside-in technique of femoral tunnel drilling
  • if performing an inside-out technique the knee is high flexed to at lease 120 degrees and a guide pin is placed through the medial portal into the medial aspect of the lateral femoral condyle at the previously determined position
  • guides are available to help monitor back the femoral condyle back wall distance which should be approximate 1-2 mm
  • the guide pin is driven out the lateral aspect of the leg through the skin
  • this is over reamed to a predetermined distance depending on the chosen graft fixation technique
  • if performing an outside-in technique the camera is placed in the anteriomedial portal for viewing, and the specific guide can be placed through the anteriolateral portal at the previously determined position
  • a separate lateral incision is made over the lateral leg, and a flip cutting drill-reamer can be used to drill the tunnel.
  • sutures are then passed through the femoral tunnel and clamped for later passing of the graft

5

Drilling the tibial tunnel

  • the tibial tunnel can be drilled either through the initial graft harvest incision if long enough, or a separate skin incision can be created
  • the tibial drill guide is placed through the anteromedial portal while the scope is viewing from the anterolateral portal
  • the guide is placed at the ACL tibial footprint in line with the medial tibial spine roughly at the posterior aspect of the anterior horn of the lateral meniscus
  • the external portion of the guide should be seated flush tot he anteromedial tibia usually midway between the anterior tibial tuberosity and the medial tibial joint line
  • attention should be paid to the degree setting on the tibial guide handle which is usually set at 7 plus the tendinous portion length of the graft
  • for instance if the tendinous portion of the graft is 40 mm, the tibial drill guide would be set at 47 degrees to provide an adequate tibial tunnel length
  • once the tunnel is drilled, the suture in the femoral tunnel can be unclamped and the looped end can be retrieved through the tibial tunnel with the aid of a probe for graft passage
H

Graft Placement

1

Pass the graft

  • the femoral sided graft sutures are placed through the looped end of the passing suture which has been brought out through the tibial tunnel
  • tension is applied as the sutures are brought through the joint and out the lateral skin.

2

Seat and secure the graft on the femoral side

  • the femoral sided graft is pulled into the femoral tunnel
  • care is taken not to pull the sutures through the bone block
  • a probe or clamp can aid in obtaining the desired orientation of the graft
  • final fixation is performed as desired

3

Seat and secure the graft on the tibial side

  • proper tensioning is applied to the graft as the tibial bone block is also fixed into place
I

Interference Screw Placement

1

Femoral interference screw

  • flex to the same degree as when drilling which should be over 120 degrees

2

Place guidewire

  • the bone tunnel can be notched to allow screw insertion
  • introduce a guide wire through the anteromedial portal while visualizing through the anterolateral portal

3

Position graft

  • position the graft within the femoral tunnel so that the screw will engage both the graft and the tunnel when placed
  • ensure that the graft is positioned so that the cancellous bone is facing the screw

4

Place interference screw

  • a cannulated tap can be used if needed
  • advance the screw over the guide wire while positioning of the graft is maintained to keep from advancing the graft into the tunnel
  • avoid damaging the tendon with the threads of the screw

5

Tibial interference screw

  • the tibial tunnel can be notched if needed
  • introduce a guide wire into the tunnel
  • apply appropriate tension on the graft through the tibial tunnel while placing the tibial screw
J

Bone grafting and Wound Closure

1

Bone grafting

  • bone grafting to the patella and tibial defect can be performed with the bone taken from the grafts as well as tibial bone if a coring reamer is used for tibial tunnel creation

2

Closure

  • the paratenon layer is first closed, then the subcutaneous tissue and skin
  • appropriate dressings are applied

Patient Care

K

Preoperative H & P

1

Perform focused orthopedic exam

  • check for effusion
  • quadricep avoidance gait (does not actively extend knee)
  • Lachman's test
  • most sensitive exam test
  • grading A= firm endpoint, B= no endpoint
  • Grade 1: < 5 mm translation
  • Grade 2 A/B: 5-10mm translation
  • Grade 3 A/B: > 10mm translation
  • PCL tear may give "false" Lachman due to posterior subluxation
  • Pivot shift
  • extension to flexion: reduces at 20-30° of flexion
  • patient must be completely relaxed (easier to elicit under anesthesia)
  • mimics the actual giving way event
  • KT-1000
  • useful to quantify anterior laxity
  • measured with knee in slight flexion and externally rotated 10-30°

2

Perform preoperative medical history and physical exam

3

Ensure biplanar images and MRI of the knee are present

4

Perform operative consent

  • describe complications of surgery including
  • surgical technical error
  • inadequate fixation
  • overaggressive rehab
  • cyclops lesion
  • infection
  • loss of motion & arthrofibrosis
  • infrapatellar contracture syndrome
  • patella Tendon Rupture
  • RSD (complex regional pain syndrome)
  • patella fracture
  • hardware failure
  • tunnel osteolysis
  • late arthritis
  • local nerve irritation
L

Perioperative Inpatient Management

1

Write comprehensive postoperative orders

2

Initiate PT POD1

  • aggressive cryotherapy (ice)
  • immediate weight bearing (shown to reduce patellofemoral pain)
  • emphasize early full passive extension (especicially if associated with MCL injury or patella dislocation)

3

Place in bledsoe brace and cryocuff

4

Discharges patient appropriately

M

Outpatient Evaluation and Management

1

Obtains focused history and performs focused exam (e.g., mechanism of injury, past knee history, past treatments, Lachman, anterior drawer, pivot shift, meniscal pain).

  • lachman's test
  • most sensitive exam test
  • grading A= firm endpoint, B= no endpoint
  • grade 1: < 5 mm translation
  • grade 2 A/B: 5-10mm translation
  • grade 3 A/B: > 10mm translation
  • PCL tear may give "false" Lachman due to posterior subluxation
  • Pivot shift
  • extension to flexion: reduces at 20-30° of flexion
  • patient must be completely relaxed(easier to elicit under anesthesia)
  • mimics the actual giving way event
  • KT-1000
  • useful to quantify anterior laxity
  • measured with knee in slight flexion and externally rotated 10-30°

2

Appropriately interprets basic imaging studies : alignment, joint space, patella alignment.

  • Radiographs
  • ensure biplanar radiographs of the knee and MRI of the knee are present
  • usually normal
  • Segond fracture (avulsion fracture of the proximal lateral tibia) is pathognomonic for an ACL tear
  • MRI
  • ACL tear best seen on sagittal view
  • bone bruising occurs in more than half of acute ACL tears
  • middle 1/3 of LFC (sulcus terminalis)
  • posterior 1/3 of lateral tibial plateau
  • subchondral changes on MRI can persist years after injury

3

Prescribes and manages non-operative treatment : Closed Chain Quad strengthening

  • physical therapy & lifestyle modifications
  • low demand patients with decreased laxity
  • increased meniscal/cartilage damage linked to
  • loss of meniscal integrity
  • frequency of buckling episodes
  • level I and II activity (e.g. jumping, cutting, side-to-side sports, heavy manual labor)

4

Preop: Makes informed decision to proceed with operative treatment

  • documents failure of nonoperative management
  • describes accepted indications and contraindications for surgical intervention

5

Provides post-operative management and rehabilitation; WB status, brace, ROM, Quad strength.

  • Postop: 2-3 Week Postoperative Visit
  • wound check
  • diagnose and management of early complications
  • Postop: 4-6 Week Postoperative Visit
  • early rehab
  • focus rehab on exercises that do not place excess stress on graft
  • appropriate rehab
  • isometric hamstring contractions at any angle
  • isometric quadriceps, or simultaneous quadriceps and hamstrings contraction
  • active knee motion between 35 degrees and 90 degrees of flexion
  • emphasize closed chain (foot planted) exercises
  • avoid
  • isokinetic quadricep strengthening (15-30°) during early rehab
  • open chain quadriceps strengthening
N

Advanced Evaluation and Management

1

Recognizes concomitant associated injuries (LCL, multiligament, OCD): PCL, Collateral ligaments, PL Corner instability, reverse pivot shift

  • Dial Test
  • Reverse Pivot Test

2

Appropriately orders and interprets advanced imaging studies: Standing views, MRI, Segond fx, bone bruising

  • Radiographs
  • Identifies Segond Fracture
  • MRI
  • ACL tear best seen on sagittal view
  • bone bruising occurs in more than half of acute ACL tears
  • middle 1/3 of LFC (sulcus terminalis)
  • posterior 1/3 of lateral tibial plateau
  • subchondral changes on MRI can persist years after injury

3

Provides complex non-operative treatment: WB status, Bracing as appropriate, vascular studies

4

Modifies and adjusts post-operative treatment plan as needed: Loss of knee motion treatment, sport specific drills, return to sport

  • Postop: 4-6 Week Postoperative Visit
  • identifies loss of knee motion
O

Complex Patient Care

1

Performs revision/transphyseal ACL reconstruction : Hardware removal, outside in drilling techniques

2

Develops unique, complex post-operative management plans

3

Surgically treats complex complications

 

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