- Discussion:
- one of most common knee injuries in children;
- most common in children between ages of 8-14 yrs;
- usually result from avulsions of anterior intercondylar eminence from pull of
ACL;
- fragment of tibial spine may be non displaced, or displaced;
- even w/ complete frx, partial ACL injury may occur w/ this injury;
- frx of posterior intercondylar eminence are rare and usually occur in skeletally mature patients.
- disruption of PCL can also be found in this injury;
-
mechanism:
- commonly caused by fall from bicycle or motorcycle;
- caused by forceful hyperextension of knee or by a direct blow on distal end of femur w/ the knee flexed;
- excessive tension on
ACL, which inserts into anterior tibial spine, results in an inter-articular fracture;
-
classification:
- anterior, posterior, or both tibial spines may be fractured;
- frx of intercondylar eminence are classified by deg of displacement;
-
type I:
- non-displaced & only anterior edge of eminence is sl elevated;
- has a posterior hinge with an elevated anterior portion;
-
type II
- partially displaced frx, w/ anterior elevation of the eminence;
-
type III A
- entire eminence lies above its bed, out of contact w/ tibia;
- this injury type usually occurs in children older than age 10-11 years;
-
type III B
- the eminence is rotated as well as out of contact;
- type III frx are most common, accounting for 83 (45 %) of frx;
- reference:
- Natural history of a Type III fracture of the intercondylar eminence of the tibia in an adult.
Sullivan D, Dines D, Hershon S: Am J Sports Med 1989;17:132-133.
- Physical Findings
- pts have pain &
hemarthrosis & are reluctant to bear wt on affected extremity;
- extremes of motion cause tenderness;
- look for associated w/ tear of medial or lateral collateral ligament;
-
PCL tear is dx'ed w/ posterior sag sign, posterior drawer, and quadriceps active test;
- Radiographic Evaluation
-
lateral radiograph:
- avulsed frag may be composed of non-ossified cartilage & may be difficult to recognize;
-
stress radiographs:
- should be made w/ pt sedated or under GEA.
- indicated w/ suspected tear of collateral ligament or physeal injury;
- look for abnormal widening of joint space;
- Reduction:
-
full extension of knee joint tends to reduce the fragment & hold it in position during healing;
-
block to full knee extension:
- block to full extension may be caused by interposition of the anterior horns of either the medial or lateral
mensici;
- attempt trial of closed reduction under anesthesia;
- if full extension is not obtained, reduction is probably not complete;
- w/ failed closed reduction in extension, consider arthroscopic assisted reduction or open reduction;
- fragment may be prevented from reduction by interposed lateral meniscus;
- type III b fractues should be treated by open reduction;
- reference:
- Entrapment of the medial meniscus in a fracture of the tibial eminence. DB Burstein et al. Arthroscopy Vol 4. 1988. p 47-50.
-
Incarceration of the meniscus in fractures of the intercondylar eminence of the tibia in children.
-
The Anatomy of Tibial Eminence Fractures: Arthroscopic Observations Following Failed Closed Reduction.
- Non Operative Treatment:
- nondisplaced or minimally displaced frx:
- some recommend immobilization of knee in full extension in long leg cast;
- some recommend immobilization w/ knee in 20 deg of flexion since ACL is most relaxed in this position;
- immobilize for four to six weeks;
- Operative Treatment:
- indicated for displaced fractures;
- procedure is carried out under
arthroscopic visualization;
- use the ACL tibial guide to effect the reduction of the intercondylar eminence fracture;
- a small incision is made just medial to the tibial tubercle;
- two guide pins are inserted on either side of the ACL thru the intercondylar fragment;
- sequentially pull the guidewires and in their place, insert a cannulated suture passer in their place;
- as each suture passer enters the joint, an arm of a No 5 ethibond suture (or
fiberwire) is placed into the mouth of the suture passer, and is then drawn out of the joint;
- tension on the sutures will firmly reduce the intercondylar eminence frx;
- the sutures are then tied over a bony bridge;
- alternatively consider arthroscopically guided screw placement that does not cross the
proximal tibial physis;
- reference:
- The Role of Arthroscopic Surgery in the Treatment of Fractures of the Intercondylar Eminence of the Tibia. JG McLennan, JBJS, 64B: 477, 1982.
- Complications
- Laxity:
- may be due to stretching of the ligament at the time of injury
- laxity is rarely severe enough to limit activities or requires treatment;
- children < ten years old are less likely to have symptomatic laxity;
- references:
- Knee instability after fracture of the intercondylar eminence of the tibia. J Pediatr Orthop 1984;4:462-464.
- Malunion:
- may cause flexion deformity of knee;
The Role of Arthroscopic Surgery in the Treatment of Fractures of the Intercondylar Eminence of the Tibia. JG McLennan, JBJS, 64B: 477, 1982.
Incarceration of the meniscus in fractures of the intercondylar eminence of the tibia in children.
Natural history of a Type III fracture of the intercondylar eminence of the tibia in an adult. Am J Sports Med 1989;17:132-133.
Fracture of the tibial spine in adults and children. A review of 31 cases.
Comminuted Tibial Eminence ACL Avulsion Fractures: Failure of Arthroscopic Treatment. EE Berg. Arthroscopy, 9: 446, 1993.
Arthroscopic Treatment of Fractures of the Tibial Spine. RG Medler and KA Jansson. Arthroscopy 10: 292, 1994.
Fractures of the Intercondylar Eminence of the Tibia. ML Molander, G Wallin, and J Wikstad. JBJS 63B: 89, 1981.
Fractures of the tibial spine in children. An evaluation of knee stability. Baxter, M.P., Wiley, J.J. J Bone Joint Surg 70-B:228-30, 1988.
Arthroscopic fixation of avulsion fractures of the tibial eminence: technique and outcome.
Biomechanical Comparison of Four Different Fixation Techniques for Pediatric Tibial Eminence Avulsion Fractures
Long-term follow-up of anterior eminence fractures. J Pediatr Orthop 1993;13:361-364.
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