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Graft-Healing-and-Return-to-Play

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					Graft Healing and
 Return to Play
   Joseph F. Scordino
   September 27, 2007
                             Case 1
   The patient was a 35-year-old forward player who sustained an
    isolated complete tear of the left anterior cruciate ligament
    (ACL) in the midst of the competitive 2001-2002 season. He was
    in contention for a position on the Italian World Cup Team that
    was to be played 135 days after his injury, only if he
    demonstrated that he could return to play at the highest level
    before the team was selected.
   What graft to use?
   What fixation to use?
   What is the basic science of graft repair and how does that effect
    the time to return to sport?
   What type of rehab?
   How early can he return?
                             Physiology
   Graft serves as scaffold which is rapidly incorporated by the host
   Similar to avascular necrosis: cell death to revascularization to cell
    repopulation to remodeling
   Cell Death: first phase in which fibroblasts dye but graft acts as scaffold for
    new ingrowth. This is an inflammatory stage.
   Revascularization: New cells grew into graft. This starts at 20 days and is
    completed at 6 months. Graft strength in some studies drops to as low as
    11%.
   Remodeling: Strength slowly returns but it never returns to its level at the very
    beginning. The fibers become more organized and take on a more
    longitudinal pattern.
   Jackson 1992 JBJS. Took a goat model and used DNA analysis to look for
    signs of replacement of graft cells with host cells. Showed that complete
    replacement of donor cells by host cells in the goat anterior cruciate ligament
    at 4 weeks after transplantation. Therefore cryopreservation in which cells
    remain alive may not be helpful.
Importance of Strong Early Fixation
   Graft fixation is crucial in ACL reconstruction
    and is the weakest link in the initial 6- to 12-
    week period, during which healing of the graft
    to the host bone occurs.
   The graft must be able to withstand early
    rehabilitation, which can consist of forces as
    high as 450 to 500 N.
   Early Fixation failure usually occurs on tibial
    side.
Fixation                                                 Ultimate Failure Load (N)     Stiffness (N/m)



Patellar Tendon
  Metal interference screw19                                                     558   —
  Bioabsorbable interference screw19                                             552   —



Soft Tissue (Femoral)
  Bone Mulch Screw (Arthrotek, Warsaw, IN)24                                   1,112               115
  EndoButton (Smith & Nephew Endoscopy, Andover, MA)24                         1,086                 79
  RigidFix (Ethicon, Somerville, NJ)24                                           868                 77
  SmartScrew ACL (Linvatec, Largo, FL)24                                         794                 96
  BioScrew (Linvatec)24                                                          589                 66
  RCI Screw (Smith & Nephew Endoscopy)24                                         546                 68



Soft Tissue (Tibial)
  Intrafix (Ethicon)25                                                         1,332               223
  WasherLoc (Arthrotek)25                                                        975                 87
  Tandem spiked washer25                                                         769                 69
  SmartScrew ACL25                                                               665               115
  BioScrew25                                                                     612                 91
  SoftSilk (Acufex Microsurgical, Mansfield, MS)25                               471                 61
   Tibial side hamstring fixation devices. A = WasherLoc,
    B = spiked washer, C = Intrafix, D = BioScrew, E =
    SoftSilk, F = Smart-Screw.
   Femoral side hamstring fixation devices. A =
    EndoButton, B = Bone Mulch Screw, C = RigidFix, D
    = Bioscrew, E = RCI Screw, F = SmartScrew.
Revascularization of Patellar Tendon
                Graft
   Anterior Cruciate Ligament Replacement using Patellar
    Tendon. An evaluation of graft revascularization in the
    dog. Arnoczky JBJS 1982. Investigated the revascularization pattern
    of patellar tendon grafts used to replace the anterior cruciate ligament in 36
    dogs by histological techniques
   Sacrificed 4 animals at 2, 4, 6, 8, 10, 16, 20, 26 and 52 weeks. Found that at 4
    weeks there was a rich synovial membrane that began to surround the graft.
    Infrapatellar fat pad and the posterior synovial tissues supplied the synovial
    sheath. Vessels progressed from a proximal and distal origin to the central
    intra articular portion of the graft
   6 weeks the graft was surrounded by a richly vascular synovial sheath. At this
    point the graft began to show evidence of avascular necrosis. Central core of
    the graft demonstrated areas of cell death, hypocellularity and collagen
    fragmentation. Zone of avascular necrosis was bound by an area of cells
    undergoing fibrocartilaginous metaplasia.
   At 8 and 10 weeks vessels began to migrate centrally. Vascular proliferation
    was accompanied by a proliferation of mesenchymal cells
       Graft Revascularization in Patellar Tendon

   Anterior Cruciate Ligament Replacement using Patellar
    Tendon. An evaluation of graft revascularization in the
    dog. Arnoczky JBJS 1982. 16 weeks showed near-completion
    of revascularization of the graft. Only a small mid portion
    remained avascular
   20 weeks the entire graft showed the presence of intrinsic
    vessels. The graft appeared hypertrophied and robust and 3x its
    original diameter. Bone wedges were complete resorbed at this
    time.
   26 weeks cellular response as well as vascularity appeared less
    proliferative
   52 weeks the specimens demonstrated a vascular pattern that was
    the same as ACL. Had normal appearing ligament with dense,
    longitudinally oriented collagen bundles.
        Histological Basic Science of
                  Allograft
   Cordrey JBJS 1963. Took 83 rabbits and harvested Achilles
    tendon 4 cm in length and then turned it 180 and resutured it
    back together and compared it to group of allografts which were
    preserved.
   Autograft at 2 days graft was covered by fine capillaries and
    became thickened and edematous this wasn’t evident until 7 days
    with the allograft. At 1 week the autograft was covered with
    intensely vascular layer of granulation tissue which was loosely
    organized and without pattern this did not became apparent with
    allograft until 2 weeks. Marked fibroblastic proliferation which
    began to become orientated longitudinally with decreased
    amounts of revascularization started at 3 weeks with autograft
    and 5 weeks with allograft.
   Allografts histologically take 1.5 to 2x as long as autograft
Background of Graft sterilization
   Heat and high doses of gamma radiation are effective
    but weaken the collagen structure.
   Use of chemical oxide while effective in removing
    unwanted microorganisms leaves behind a chemical
    residue which can cause chronic synovitis
   Recommend use sterile techniques to harvest graft, low
    dose radiation may help, repeated soaks in antibiotic
    solution and multiple cultures during processing
                 Strength of Allograft
   A comparison of patellar tendon autograft and allograft used for
    anterior cruciate ligament reconstruction in the goat model. Jackson et
    al. American Journal of Sports Medicine 1993. Goat model of 40
    specimens. Compared strength and histological model at 6 weeks and 6
    months. Found at 6 months that the autograft reconstructions
    demonstrated smaller increase in anterior-posterior displacement, values of
    maximum force to failure 2x greater, significant increase in cross-sectional
    area, smaller fiber size (which shows faster remodeling). Found that at time
    zero graft strength is the same at 6 months there is a difference and allograft
    is ½ as strong.
   Allografts demonstrate a greater decrease in their implantation structural
    properties, a slower rate of biological incorporation, and the prolonged
    presence of an inflammatory response.
       Strength of BTB with time
   Anterior and posterior Cruciate Ligament
    Reconstruction in Rhesus Monkeys. Clancy
    et al. JBJS 1981. Took 29 rhesus monkeys and
    performed BTB autograft and then measured
    grafts to failure. At 3 months there was 53% of
    strength compared to opposite side, 52% at 6
    months, 81% at 9 months and 81% at 1 year.
                   Remodeling Phase
   Shino et al demonstrated that by 52 weeks after surgery, bone-patellar
    tendon-bone allografts implanted in dogs had regained a fibrous framework
    histologically similar to normal ligament.
   Falconiero et al. Arthroscopy 1998. Took 43 patients and took biopsy
    samples of their ACL from 3 months to 120 months after ACL
    reconstruction. Placed patients into 4 groups. 3 to 6 months, 7 to 12
    months, more than 12 months and a control group. Biopsy specimens were
    evaluated for vascularity, cellularity, fiber pattern, and metaplasia. Found that
    fiber pattern, cellularity, vascularity, and degree of metaplasia obtained gross
    histological similarity with a normal ACL by 12 months after autogenous
    reconstruction. Found that vascularity and fiber pattern were the same with
    normal ACL after only 6 months which he felt was the strongest evidence to
    early return to play.
        Healing at attachment site
   In the early stages the most likely place of failure will be
    at the fixation site in the bone tunnels.
   Tendon-healing in a bone tunnel: a Biomechanical and
    histological study in the dog. Rodeo et al. JBJS 1993.
    Took 20 adult mongrel dogs and looked for pullout
    strength of tendon fixed into a tibial tunnel drill hole
    similar to BTB. Found that up to 8 weeks tendon
    pulled from bone but after 12 weeks the graft torn
    midsubstance.
   Compared to bone patellar bone healing which takes on
    fracture healing type characteristics with healing which
    typically occurs at 6 weeks.
    Effect of Early Rehab on Laxity
   Rehabilitation after hamstring anterior
    cruciate ligament reconstruction. Majima
    CORR 2002.
    Compared early more aggressive rehab to
    standard treatment. Found no increase in graft
    laxity or difference at 1 to 2 years. In early
    stages showed increased muscle strength with
    faster return to full muscle strength at the cost
    of more effusions and increased synovitis.
            Hamstring Early Rehab
   Brace-Free Rehabilitation, with Early Return to Activity, for Knees
    Reconstructed with a Double-Looped Semitendinosus and Gracilis
    Graft. Howell et al. JBJS 1996. 41 patients with doubled loop gracillis and
    semitendinous graft studied if 1) brace had effect on rehab 2) early return to
    sport changed stability of knee from 4 months to 2 years 3) did knee
    maximally improve at 4 months. At 4 months allowed to return to
    unrestricted activities and then patients returned at 2 years. Found no pivot
    shift and normal lachmans in 82% and KT 1000 < 3 mm in 88%.
   Stability remained unchanged at two years, justifying the early return to
    vigorous activities at four months. The girth of the thigh, the extension of the
    knee, and the Lysholm and Gillquist score were the same at four months as at
    two years, verifying the success of the brace-free intensive rehabilitation
    program in the restoration of early function to the treated knee. However,
    some continued improvement was observed in the performance of the one-
    leg-hop for distance test between four months and two years.
    Evidence for Early Patellar Tendon
          Graft Return to Play
   Effect of early versus late return to vigorous
    activities on the outcome of anterior cruciate
    ligament reconstruction. Glasgow et al.
    American journal of Sports Medicine. 1993.
    Effect (mean 5 months) versus late (mean 9
    months) return to vigorous cutting activity on
    long-term outcome of anterior cruciate
    reconstruction was studied in 64 patients. By
    clinical examination, subjective evaluation, KT
    1000 there was no difference in either group.
             Typical Rehab Program
   Phase I (duration, 2-3 wk)Early range-of-motion exercises with emphasis on gaining
    full knee extension; weight-bearing as tolerated after bone-patellar tendon-bone
    procedure and touch-down weight-bearing after semitendinosus-gracilis procedure;
    straight-leg strengthening, functional exercise, and gait training. Goals for progression
    to phase II: minimal pain and effusion, 0°-100° range of motion of knee, good
    quadriceps contraction
   Phase II* (duration, 2-3 mo)Endurance training (bicycling, stair-stepper, etc.);
    progressive resistance training (leg presses, calf presses, mini-squats, hamstring curls,
    etc.), with emphasis placed initially on low resistance and multiple repetitions and then
    gradually replaced with sets of increasing resistance and fewer repetitions; battery of
    balance exercises and beginning-level plyometric exercises. Goals for progression to
    phase III: full range of motion, hopping on one leg without pain
   Phase III (duration, 3-6 mo)
    Continued progressive resistance and endurance training; jogging/running progression
    and advanced plyometric exercises; advanced strengthening and functional exercise
    training to prepare individual for full return to activity/sports. Goals for returning to
    full activity: 90% strength and performance ability compared with uninvolved lower
    extremity
           Return to Play Criteria
   Return to play based on full range of motion with
    “good” muscle strength and muscle balance.
   Can compare side to side hamstring and quad strength.
    85% compared to contralateral of quad and 100% of
    hamstring).
   Can use serial KT 1000 < 3mm to ensure continued
    stability and no increase in laxity.
   Functional testing can provide a global assessment of
    the ability of the knee to perform sports-related
    activities. Can use single leg hop, timed single leg hop
    for 20 feet, and the vertical jump for functional testing
    (85% compared to opposite side).
          Data of Graft Rupture
   Incidence and risk factors for graft rupture
    and contralateral rupture after anterior
    cruciate ligament reconstruction. Salmon et
    al Arthroscopy 2005. 675 reviews with BTB
    and hamstring were reviewed after 2 years. Had
    an incidence of 6% of rupture rate the same as
    contralateral side after 12 months. However
    before 12 months increased incidence of graft
    rupture on operative side.
      Italian Soccer Player Returns
   The patient underwent an arthroscopically assisted ACL reconstruction with a
    double-loop semitendinosus-gracilis autograft 4 days after the injury. Eight
    days after surgery he began rehabilitation at a rate of 2 sessions a day, 5 days a
    week, plus 1 session every Saturday morning. These sessions were performed
    in a pool for aquatic exercises, in a gymnasium for flexibility, coordination,
    and strength exercises, and on a soccer field for recovery of technical and
    tactical skills, with continuous monitoring of training intensity.
   The surgical technique and the progressive rehabilitation program allowed the
    patient to play for 20 minutes in an official First Division soccer game 77 days
    after surgery and to play a full game 90 days after surgery. Eighteen months
    postsurgery, the player had participated in 62 First Division matches, scoring
    26 times, and had received no further treatment for his knee.
                    Summary
   Importance of early fixation strength
   Allograft histologically may take 2x as long to
    incorporate
   Lack of data or sufficient numbers to report on
    early return to play

				
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