Intercondylar Eminence Fracture : Wheeless' Textbook of Orthopaedics

- 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. A case report.

- 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 (most often) or lateral meniscus (rare);
         - 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;
- references:
- Entrapment of the medial meniscus in a fracture of the tibial eminence.
                - 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.
                - Tibial eminence fractures in children: prevalence of meniscal entrapment.

- 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;
- ref: Nonoperative treatment of tibial spine fractures in children-38 patients with a minimum follow-up of 1 year.

- 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;
    - need to tension the reduction (over reduction)
           - intersubstance stretching of ACL occurs in associationwith the tibial spine fracture and therefore, overreduction
                    may be considered;
           - excessive ACL tightening is not associated with poor outcomes;
         - well-reduced tibial eminence fractures showsubtle increases in anteroposterior knee laxity, albeit without functional deficit;
    - reference:
- The Role of Arthroscopic Surgery in the Treatment of Fractures of the Intercondylar Eminence of the Tibia.
           - Open Versus Arthroscopic Reduction for Tibial Eminence Fracture Fixation in Children

- 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.
                 - Clinical and radiological results of arthroscopically treated tibial spine fractures in childhood.
                 - Laxity and functional outcome after arthroscopic reduction and internal fixation of displaced tibial spine fractures in children.
    - Malunion:
- may cause flexion deformity of knee