Tibial eminence fractures

Usually follow hyperextension injuries, or direct blow to distal femur with the knee flexed.

Fractures of the posterior intercondylar eminence are rare and usually occur in skeletally mature patients.

Classification

Meyers and McKeever (1959)

I. Minimal displacement and high degree of bony apposition
II. Displaced with some bony apposition, hinges posteriorly
III. Displaced, NO bony apposition

Modification added by Zaricznyj (1977).

IV. Displaced and comminuted

Treatment

Type I - Conservative

Controversy about position of knee, Latest article 2002 patients tolerate knee in full extension

Suggest full extension or 10 degrees of flexion cylinder cast for 6 weeks. then remove and mobilise.

Type II and III displaced fractures treatment is controversial see references below.

Seems to be agreement that conservative management placing patients in extension does not ensure reduction. Reduction stopped by transverse meniscal ligament in British series, and held up by attachment of anterior horn of lateral meniscus and anterior cruciate in American series.

Suggested treatment algorithm based mostly on British article.

Place in full extension if reduces place in cylinder cast for 6 weeks. If not reduced proceed to arthroscopic assessment and reduction, if remains reduced in extension place knee in cylinder cast in full extension, non weight bearing six weeks with serial radiographs at week 1 and 2 to ensure non displacement. Cast off after six weeks followed by physio and mobilisation

If able to arthroscopically reduce fracture, but unable to hold reduced in extension or displaces suggest fix either arthroscopic assisted or open.

Flynn 2002 described an arthroscopic assisted way of holding the fracture reduced with absorbable sutures.

Complications

Despite anatomical closed or open reduction, some residual ligamentous laxity seems inevitable after fractures of the tibial eminence in children, but this laxity seldom is severe enough to limit activities or to necessitate treatment. In a long-term follow-up study, Willis et al found objective evidence of ligamentous laxity in thirty-seven (74%) of fifty children, although none complained of instability at the time of the follow-up. Wiley and Baxter found, after three to ten years of follow-up of forty-five patients, that none had subjective feelings of instability although clinical testing indicated instability in twenty-three (5%1). Wiley and Baxter suggested that the absence of a pivot shift in these patients was related to the enlargement of the tibial eminence due to the increased blood supply during the healing stage. Smith reported evidence of mild-to-moderate laxity of the anterior cruciate ligament in all fifteen children who had a fracture of the tibial eminence in his series; all of the patients reported feeling some instability in the affected knee. Gronkvist et al found that children who were less than ten years old at the time of the injury were less likely to have instability, probably because additional skeletal growth compensated for the elongated ligament and the displacement of the fracture. Twelve (38%) of their thirty-two patients had residual symptoms in the knee, mainly giving-way and transient locking of the knee joint, and in eight patients, the symptoms were severe enough to limit activities. All but one of these twelve patients were more than ten years old (mean age, fourteen years) at the time of the injury. Rarely, malunion of a fracture of the tibial eminence may cause a flexion deformity of the knee that may necessitate excision of the fibrous non-union and reattachment of the anterior cruciate ligament to its normal anatomical insertion.

References

JBJS -A: 52:1677-84 (1970) - Fracture of the intercondylar eminence of the tibia.

JBJS - B: 84: 579-582 (2002) - An alternative to fixation of displaced fractures of the anterior intercondylar eminence in children

JBJS - A 84:1933-1938 (2002) - The Anatomy of Tibial Eminence Fractures: Arthroscopic Observations Following Failed Closed Reduction