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Pediatric Anterior Cruciate Ligament Tear M23.50 717.83

normal acl scope picture

ACL mri picture

ACL blood supply picture

ICD-9 Classification / Treatment
Etiology / Natural History Associated Injuries / Differential Diagnosis
Anatomy Complications
Clinical Evaluation Follow-up Care
Xray / Diagnositc Tests Review References

synonyms: ACL



A- initial encounter

D- subsequent encounter

S- sequela

Pediatric ACL ICD-9

  • 717.83 = old disruption of anterior cruciate ligament.
  • 844.2 = sprain and strains of knee and leg; cruciate ligament of knee.

Pediatric ACL Etiology / Epidemiology / Natural History

ACL Anatomy

  • Origin: Lateral wall of the intercondylar notch at its posterior aspect (Arnoczky CORR 1983;172:19)
  • Insertion: Oval shaped area, anterior aspect of the tibial plateau between the tibial eminences. (Arnoczky CORR 1983;172:19)
  • Function: Primary restraint to anterior tibial translation (90%); Secondary restraint to tibial rotation; Minor secondary restraint to varus-valgus angulation at full extension.
  • Blood supply: Middle genicular artery which arises from popliteal A.  The inferior medial and lateral genicular A also vascularize the ACL via the fat pad. (Arnoczky SP, Orthop Clin North Am 1985;16:15)
  • Innervation: Posterior articular nerve (a branch of the tibial nerve) (Kennedy JC, JBJS 1974;56A:223). Normal ACL has proprioceptive senses that help protect the knee joint during use which are lost after reconstruction.
  • Length = 31-38mm, Width = 11mm (Girgis CORR 1975;106:216) (Odenstein JBJS AM 1985;67:257)
  • Anteromedial portion is tighter in flexion, posterolateral portion is tighter in extension
  • Intracapsular, but extrasynovial
  • Tensile strength = 2,150 N, stiffness = 242 N/mm. Tension forces in the ACL are highest with the knee in full extension (Markolf KL, JBJS 1996;78A:1728).
  • Composition: Type I collagen (90%), Type III collagen (10%)

ACL Clinical Evaluation

  • Noncontact injury occuring while changing direction or landing from a jump.  Often feel or hear "pop"
  • Hemarthrosis noted within a few hours. Moderate to severe effusion usually present
  • ROM may be limited by pain, hamstring spasm, ACL impingement, meniscal tear
  • Aspiration under sterile conditions may provide relief, allow examination for blood and may allow improved physical exam.
  • Lachman test- best test for ACL laxity.  Knee placed in 20-30 degress of flexion, the femur is stabilized, and an anteriorly directed force  applied to proximal calf.    Compare to uninjured side. Grade 1+ = 1-5mm increased translation; 2+= 6-10mm ; 3+=>10mm.
  • Pivot shift test-  Confirms complete ACL tear. Based on very early flexion causing anterior subluxation of the tibia that is reduced with further flexion (20-40 degrees) due to the posterior pull of the iliotibial tract.  Relocation event graded as 0(absent), 1+ (pivot glide), 2+(pivot shift), 3+(momentary locking) (Galway HR, JBJS 1972;54Br:763)
  • Anterior drawer test- anterior force applied at 90 degrees of  flexion.  Least reliable.
  • Always examine for Posterolateral Corner Injury
  • KT-1000 testing - difference of  <3mm compared to uninjured knee is normal.  Greater than or equal to 3mm is pathologic.
  • EUA provides more reliable exam.
  • The International Knee Documentation Committee (IKDC) activity levels: level I, jumping, cutting, and pivoting sports (football, basketball, soccer); level II, heavy manual labor, side-to-side sports (skiing, tennis); level III, light manual work, noncutting sports (jogging, running); and level IV, sedentary activity without sports.

Pediatric Peds ACL Xray

  • A/P and Later knee
  • MRI has a 64% sensitivity and 94% specificity for ACL tears in children and adolescents.  For meniscal tears it is 83% sensitive, 95% specific. (Zobel MS, Radioliogy 1994;190(2):397-401)
  • often associated with bone bruises represented by increased (bright) signal intensity on T2-weighted images and decreased (dark) signal on T1-weighted images in the subchondral marrow, secondary to hemorrhage and edema. Bone contusions frequently occur on both tibial and femoral sides of the joint and are most frequently seen on the lateral side. (Spindler KP, Am J Sports Med 1993;21:551-557) ( Graf BK, Am J Sports Med 1993;21:220-223)

Pediatric ACL Treatment

Pediatric ACL Associated Injuries / Differential Diagnosis

  • Meniscus tear occurrs in 50%-71% of adolescents with ACL tears initially treated nonsurgically. (McCarroll JR,  Am J Sports Med 1994;22:478-484) (Graf BK, Arthroscopy 1992:8:229-233)
  • Tibial Eminence Fracture
  • LCL, Posterolateral corner combined injury
  • MCL: need for concurrent repair is dependent on amount of valgus laxity.  2-3mm increased laxity is probably not detrimental.  Absolute indication for MCL repair has not been established.
  • Chondral injury.
  • PCL tear
  • ACL Deficiency with varus angluation: Correction of varus alignment with high tibial osteotomy and delayed ACL  reconstructive procedures are recommended (Noyes FR, Am J Sports Med. 2000;28(3):282-9). Concomitant ACL reconstuction and HTO is an alternative.
  • Patellar Dislocation
  • Popliteus avulsion
  • Knee Dislocation

ACL Complications

  • Growth disturbance, leg length inequality
  • Loss of stability / Graft failure: @10%
  • Anterior knee pain / kneeling pain: 17.4%/100% BTB, 11.5% Hamstring
  • Stiffness: 6.3%
  • Painful hardware: 6.3%
  • Infection: <2%
  • Patellar fracture / patellar tendon rupture: <1% (BTB grafts)
  • Arthritis: incidence after reconstruction is unkown
  • Arthrofibrosis: rare
  • Cyclops lesion: rare
  • NVI (saphenous neuralgia): rare
  • Complex Regional Pain Syndrome: rare
  • Hemarthrosis

ACL Reconstruction Follow-up  care

  • Hinged knee brace locked at 15 degrees for 6 days
  • WBAT with crutches, discontinue crutches when comfortable, usually @ 2 weeks
  • 1wk post-op: brace opened to 15 degrees to unlimited flexion.  Knee brace may be removed when non-weight bearing
  • Physical therapy 2-3x/wk for 12 weeks.   After 1wk may begin low-resistance stationalry bike out of brace, quad sets, straight leg raises, early hamstring resistance exercises, closed-chain exercises with elastic cord.
  • Bracing discontinued when patients have excellent muscle control about knee, generally 6weeks.
  • 6wks=stair-climbing
  • 12wks=cleared for all activities except: running on hard surfaces, terminal knee extensions with resistance, and jumping/pivoting sports. 
  • 6months=may do running and terminal knee extensions
  • 8months=if 90% of hamstring and quadriceps strength have been regained and patient has full unrestricted ROM they may return to full, unrestricted sport with functional knee brace.
  • Persistent effusion and failure to regain full extension indicates graft impingement. (Howell JBJS Am 1993;75:1044-1055.)
  • Consider Home-based rehab (Howell, SM):
    -Begin towel extension exercises immediately.
    -Weeks 2-4: walk, swim, bike with high seat, no resistance. Should be able to extend and flex knee fully be 4 weeks, will have mild thigh atrophy and mild swelling.
    -Weeks 4-8: May use all weight machines with low weight and 20 reps. By 8weeks should have full ROM with little/no swelling.
    -Weeks 8-16: Begin running. If running straight without difficulty at 12 weeks begin agility exercises and jumping. By 16 weeks if knee is stable and pt can run and jump without difficult gradual return to full activities is allowed.
  • Driving: may drive after 6 weeks for right leg; 2 weeks for left leg. (Nguyen T, Knee Surg Traumatol Arthrosc. 2000;8:226).
  • see also Grant JA, JAAOS 2005 33:1288.
  • ACL Reconstruction Rehab Protocol.

Pediatric ACL References

  • Pressmen AE, Anterior cruciate ligament tears in children: an analysis of operative versus nonoperative treatment.  J Pediatr Orthop 1997;17(4):505-11
  • Angel KR, Anterior cruciate ligament injury in children and adolescents. Arthroscopy 1989; 5(3): 197-200
  • Janarv PM, Anterior cruciate ligament injuries in skeletally immature patients. J Pediatr Orthop, 1996;16(5): 673-7
  • Kannus P, Jarvinen M. Knee ligament injuries in adolescents. Eight-year follow-up of conservative treatment. J Bone Joint Surg 1988;70-B:772-6