Transcript Graft Healing and Return to Play

Graft Healing and
Return to Play
Joseph F. Scordino
September 27, 2007
Case 1
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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
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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
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Graft fixation is crucial in ACL reconstruction
and is the weakest link in the initial 6- to 12week 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
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Bioabsorbable interference screw19
552
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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
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
Soft Tissue (Tibial)
Intrafix (Ethicon)25
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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 oneleg-hop for distance test between four months and two years.
Evidence for Early Patellar Tendon
Graft Return to Play
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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
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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
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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
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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
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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
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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