ACL Injuries In the Skeletally Immature

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ACL Injuries In the Skeletally Immature

• Jason W. Folk, MD
• Steadman Hawkins Clinic of the Carolinas
• February 2012

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Disclosures

• Consultant Smith Nephew Endoscopy

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Objectives

• Describe the epidemiology, pathophysiology, and
  treatment principles of ACL injuries in
  skeletally immature patients

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ACL Injuries Introduction

• Epidemiology
• Intrasubstance tears once considered rare in
  pediatric population
• Tibial eminence fx considered pediatric ACL
  equivalent
• Typically under 12yo
• Increasing numbers over past decade
• Increased attention

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ACL Injuries Introduction

• Reasons for increased incidence
• Increased participation in sports
• Higher competitive levels early on
• Increased awareness of injury
• Decreased conditioning

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ACL Injuries Introduction

• ACL Injuries in Soccer Players 5-18 (Shea, et al.
  JPO 2004.)
• Based on insurance data from 6 million
  player-years
• 6.7 of total injury claims
• 30.8 of all knee injury claims
• True incidence unknown

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ACL Injuries Introduction

• Differences in pediatric population
• Often lack fully developed complex motor skills
• May have temporary decline in motor and balance
  during puberty
• Open physes
• Higher strength of ligaments vs. bone-ligament
  interface

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ACL InjuriesDiagnosis

• History
• Patient describes a characteristic Pop
• Effusion forms quickly after injury
• 47 of patients aged 7-12 with traumatic
  effusion had ACL disruption
• 65 in 13-18 year old group. (Stanitski et al.
  1993)
• Approximately 60 partial tears

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ACL Injuries Diagnosis

• Physical Exam
• Often more difficult in kids than adults
• Acute pain
• Frightened
• Unable to relax
• Examine uninjured leg for baseline laxity or
  congenital absence of ACL

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ACL Injuries Imaging

• Plain Radiographs (4 views)
• For anyone suspected of having an ACL injury
• Bony avulsions
• Osteochondral fractures
• Physeal fractures
• Patellar dislocation/subluxation
• Degree of physeal closure
• CT scan also used for evaluation of physeal
  closure.

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Tibial Eminence Fracture

• In skeletally immature, chondroepiphysis is
  weaker than the ligament.
• Mechanism of injury typically hyperflexion
• Most commonly 8-12yo
• Present w/ pain and limited ROM
• Dx on x-ray and CT

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Tibial Eminence Fracture

• Type I LLC x 3-6 weeks in 20degrees flexion
• Type II/III Attempted closed reduction,
  aspiration of hemarthrosis (may help reduction),
  LLC in extension x 4-6 weeks
• Irreducible Type II/III or IV arthrocopic vs
  open ORIF with suture, retrograde wire, or screw
  fixation
• Some argue all Types II-IV should be fixed
  anatomically with countersinking of fragment
  because of residual laxity
• Results of fixation usually excellent

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ACL Injuries Imaging

• MRI
• Should not be used as replacement for physical
  exam and routine radiographs
• Look for ACL tear, meniscal injury, chondral
  injury
• Indications
• Failing to improve ROM
• Persistent effusion
• Physical exam difficult to interpret.
• Help define anatomy of physis

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ACL Injuries Etiology

• Can occur with fractures
• Distal femoral physeal fractures (25-45)
• Salter-Harris III fxs at increased risk because
  frequently exits intra-articularly at notch
• Proximal tibial physeal fractures

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The Physis

• Concern about iatrogenic injury to physis is what
  drives the debate about treatment strategies

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The Physis

• Distal femoral and prox tibial physis
• Contribute more to limb length than hip and ankle
• DF 1.2 cm/yr
• PT 0.9 cm/yr
• Overall 65 of length contributed to knee
• Closure typically occurs
• M16
• F14

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Anatomy of Physis

• MRI closure of Physis
• 0 at 11 years
• 5 at 12 years
• 34 at 13 years
• 53 at 14 years
• 94 at 15 years
• 100 at 16 years
• Central tibial physis closes prior to peripheral
  physis
• ?More central tunnel
• ?Smaller tunnel
• Sasaki et al., J Knee Surg 2002

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ACL InjuriesTreatment

• Concern for possible growth abnormality fuels
  debate on treatment
• Non-operative
• Operative
• Direct Repair
• Extra-articular
• Intra-articular
• Intra/Extra articular reconstructions
• Physeal sparing
• Partial Transphyseal
• Complete transphyseal
• Trans epiphyseal

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ACL InjuriesNonoperative Management

• Avoids risk of physeal damage
• Sometimes used as a temporizing measure until
  skeletal maturity
• Very difficult to reasonably limit young
  patients activities

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ACL InjuriesNonoperative management

• So what if we dont treat these injuries?
• Angel et al. Arthroscopy 1989
• 27 children with arthroscopically documented ACL
  tears
• 22 patients at 51mo f/u
• None able to return to sports at preinjury level

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Non-op ACL Open Physis

• 40 pts under 14 y/o open physis
• 16 conservative
• 6 scope for meniscal tears
• Only 7 return to sports
• All recur giving way, swelling, pain
• McCarroll et al., AJSM 1988

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Non-op ACL Open Physis

• 18 pts ACL injury open physis
• Only one returned to preinjury level of sports
• Initial scope 13 meniscal tears
• Later secondary meniscal tears in 9
• Degen changes 11 of 18 pts by Xray
• Mizuta et al., JBJS Br 1995

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Non-op ACL Open Physis

• 60 children with ACL tear
• 23 nonop
• Nat Hx continued instability, further meniscal
  and chondral damage
• 25 secondary meniscal tears
• Few able to participate in sports
• Aichroth et al., JBJS BR, 2002

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Non-op ACL Open Physis

• ? Effect of delay in treatment
• 39 pt lt 14 y/o
• Sig increase in MMT with delay in treatment gt 6
  weeks
• 36 chronic vs 11 in acute Rx
• No diff in rate of LMT
• Millett et al., Arthroscopy 2002

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ACL InjuriesNonoperative Management

• Graf et al
• 12 skeletally immature patients with ACL tears
• 8 patients underwent non-op and no restriction
  management.
• 7 of the 8 had new meniscal tear at follow up

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ACL InjuryLong Term Results

• Kannus et al. JBJS-B. 1988
• 8 year F/U 4/7 Pediatric Patients that had
  Untreated ACL Tears showed Advancing OA
  radiographically

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Nonoperative Rx in Children

• Non-op treatment has not resulted in good
  outcomes

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ACL InjuriesPhyseal Concerns

• Fear disruption of open physes
• Risk of epiphysiodesis, LLD, angular deformity
• Caused by crossing physis with bone plug and/or
  fixation devices

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ACL InjuriesPhyseal Concerns

• History
• Campbell et al. (1959)
• Large holes drilled through the physis have
  maximal retardation of growth plate
• Insertion of cortical bone across physis causes
  arrest
• Makel et al (1988)
• Destruction of gt7 of physis causes growth arrest
• Destruction of 3 or lessno arrest
• Stadelmeir et al (1995)
• Soft tissue graft placed in drill hole did not
  cause physeal bar.

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Factors Influencing Physeal Arrest

• Diameter of drill hole
• Soft tissue graft within tunnel
• Tension of graft across physis
• Tunnel location? (Central and vertical)

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ACL Injuries Operative Managment

• Direct Repair
• A historic treatment modality
• Inflammatory changes and degeneration begins
  within 48 hours after injury
• Metalloproteases and cytokine inflammatory
  factors affect healing potential of direct repair
  
• Poor results
• Delee and Curtis, CORR 1983
• Engebretsen, et al. Acta Orthop Scand 1988

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ACL InjuriesOperative Management

• Extra-Articular repair
• Temporizing method
• Non-anatomic reconstruction
• Poor results
• Dahlstedt , et al. Acta Orthop Scand 1988
• McCarroll et al. AJSM 1998
• Graf, et al. Arthrsocopy 1992

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ACL Injuries Assessment of maturity

• Tanner et al.
• Adolescent growth spurt begins at 12.5 years in
  boys and 10.5 years in girls.
• Peak Growth velocity 1 year later
• Menarche is good indication of maturity in girls
• In athletic girls, menarche may be delayed.
• Axillary and pubic hair appear in boys after
  growth spurt
• Bone age Most accurate method to determine
  skeletal maturity

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General Guidelines

• Think about physis if
• Male
• Tanner stage 1 or 2
• Not shaving
• Not reached growth spurt
• 14 y/o or less
• Female
• Premenarchal
• Tanner stage 1 or 2
• Not reached growth spurt
• 12 y/o or less

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ACL Reconstruction Techniques
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ACL InjuryPhyseal Sparing Reconstruction

• Intra-articular, non-anatomic, extra-physeal

Stanitski. JAAOS 1985
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ACL InjuryKocher Technique
Physeal-Sparring Combined Intra- and
Extra-articular Reconstruction
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ACL InjuryPartial Transphyseal

• Hybrid of physeal sparing and adult-type
  reconstruction
• Femoral physis left intact
• Graft Hamstring or patella
• Passed through 6-8mm tunnel
• lt5 physeal X-sectional area
• Fixed in over the top position

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ACL InjuryTransepiphyseal
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ACL InjuryTransphyseal
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Thank You