Case Report
http://dx.doi.org/10.14517/aosm15022
pISSN 2289-005X·eISSN 2289-0068
Arthroscopic fixation with a cannulated screw for avulsion
fractures of the tibial spine in children: a report of two cases
Jin Wan Kim, Youn Soo Hwang, Kyu Pill Moon, Kyung Taek Kim, Joon Yeon Song
Department of Orthopedic Surgery, Dong-Eui Medical Center, Busan, Korea
An anterior cruciate ligament (ACL) avulsion fracture of the tibial spine is uncommon and occurs mostly in pediatric patients. Pediatric ACL avulsion fractures can be treated surgically through arthroscopic surgery or open surgery. Recently,
arthroscopic surgery has been performed more often than open surgery because the former has been associated with a
lower incidence of postoperative complications. Screws, K-wires, and suture anchors have been used as fixative devices
during an arthroscopic fixation. Cannulated screw fixation is a simple method for a solid fixation, but it has the risk of
causing damage to the growth plate. We report favorable results using a cannulated screw for two cases of pediatric ACL
avulsion fractures.
Keywords: Tibial spine; Avulsion fracture; Cannulated screw; Child
INTRODUCTION
The anterior cruciate ligament (ACL) avulsion fracture of
the tibial spine was first described in 1875 by Poncet [1].
ACL avulsion fractures at the tibial spine occur through
either severe torsion-induced injury or valgus or varus
injury but rarely through direct injury. Avulsion fractures
are caused because the ACL attachment at the proximal
tibial epiphyseal plate is anatomically weak rather than
because the ACL itself receives traction force due to hyperextension of the knee. In particular, it frequently occurs in children and adolescents aged between 8 and 12
years [2–4]. Twisting injuries and bicycle falls are known
to be the most common etiological causes of an ACL
tibial spine avulsion fracture [5,6], but it was recently reported to have occurred in adults as a result of traffic accidents and sports injuries [7].
The treatment of ACL avulsion fractures of the tibial
spine can be divided into conservative treatment and surgical treatment. The surgical treatment includes fixation
through arthroscopic surgery or open surgery. Various
methods of arthroscopic fixation have been studied such
Arthroscopy and
Orthopedic Sports Medicine
AOSM
as fixation through K-wires, pull-out suture, suture anchors, or cannulated screws with wires or alone [8]. The
advantages and disadvantages of each method have been
reported, yet the gold standard of surgical technique has
not been established. In this study, we report, along with
a review of the current literature, of satisfactory outcomes
after two patients with ACL avulsion fractures of the tibial
spine underwent an arthroscopic fixation using cannulated screws.
CASE REPORTS
Case 1
An eight-year-old girl was admitted to hospital because
of instability and pain in her right knee after she sustained a twisting injury while running. Through physical
examination, we found that the patient presented with
tenderness and swelling in the right knee. Also, the patient was positive for the anterior drawer test and for the
lachman test (++/++) and had a Lysholm knee score of
65. Through preoperative simple radiography (Fig. 1A)
and magnetic resonance imaging (Fig. 1B), we found a
Received November 3, 2015; Revised December 2, 2015; Accepted December 2, 2015
Correspondence to: Youn Soo Hwang, Department of Orthopedic Surgery, Dong-Eui Medical Center, 62 Yangjeong-ro, Busanjingu, Busan 47227, Korea. Tel: +82-51-850-8937, Fax: +82-51-850-8943 , E-mail: [email protected]
Copyright © 2016 Korean Arthroscopy Society and Korean Orthopedic Society for Sports Medicine. All rights reserved.
This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/
by-nc/4.0) which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
CC
Arthrosc Orthop Sports Med 2016;3(1):49-53
49
Jin Wan Kim, et al. Cannulated screw fixation of ACL avulsion fracture
A
A
B
B
Fig. 1. (A) A preoperative plain radiograph of an eight-year-old girl with type
III avulsion fracture of the tibial spine
(arrows). (B) A preoperative magnetic
resonance image of an avulsion fracture
of the anterior cruciate ligament (arrow).
C
Fig. 2. Arthroscopic findings of an avulsion fracture of the anterior cruciate ligament and a hematoma (A), an incomplete tear of the lateral meniscal
posterior horn (B), and an accurate fixation with a cannulated screw (C).
A
Meyers-McKeever type III avulsion facture in which the
tibial intercondylar eminence was completely separated
from the tibial attachment site. The size of the bone fragment was nearly 1.6 cm in length and 1.1 cm in width.
The surgery was performed around a week of the injury.
Through arthroscopic examination, we found that the
50
B
Fig. 3. Arthroscopic findings at the 6th
postoperative week show the healed
avulsed bony fragment (A) and the completely healed lateral meniscus (B).
avulsion fracture fragment was completely separated
from the ACL attachment site (Fig. 2A) and that the posterior horn of the lateral meniscus was torn incompletely
and longitudinally (Fig. 2B). We obtained an anatomical
reduction using an arthroscopic probe or a microfracture
pick with the knee in 30o to 90o of flexion. Under C-arm
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Jin Wan Kim, et al. Cannulated screw fixation of ACL avulsion fracture
fluoroscopy, a guide pin was inserted through the superior medial portal, and the fracture fragment was fixed
by inserting a 4.0 mm cannulated screw following the
guide pin (Fig. 2C). When inserting the guide pin, we took
care not to penetrate the growth plate and to damage the
medial femoral condyle by the screw thread. The incomplete tear of the posterior horn of the lateral meniscus
was conservatively treated. As part of the postoperative
rehabilitation program, the patient was allowed partial
weight-bearing and was applied a cylinder splint for 3
weeks, after which range of motion exercises of 0o to 90o
and full weight-bearing were allowed. By the 5th postoperative week, we found that the patient was clear of
pain and discomfort in the knee. We found the following
postoperative findings: a successful bony union through
plain radiography; a full range of motions; normal lachman and anterior drawer test results; and a Lysholm knee
score of 82. A secondary arthroscopic examination was
A
performed six weeks after the surgery during which we
found that the avulsed bony fragment was completely
healed, so the cannulated screw was removed (Fig. 3A).
Despite the fact that we did not attempt any reparative
measures, we observed that the lateral meniscal tear was
spontaneously resolved (Fig. 3B). At a 1-year follow-up,
the patient was able to exercise a complete range of motions without gait disturbance and showed no symptoms
of instability.
Case 2
A nine-year-old boy was admitted to hospital for pain
and swelling in his left knee as a result of a direct injury
while running. Through physical examination of the patient, we found that he had tenderness and swelling in his
left knee, positive results for the anterior drawer test and
for the lachman test (++/++), and a Lysholm knee score
of 54. Through preoperative simple radiography (Fig. 4A)
B
C
Fig. 4. (A) Preoperative plain radiographs of a nine-year-old boy with type III avulsion fracture of the tibial spine (arrows). (B) A preoperative magnetic
resonance image of an avulsion fracture of the anterior cruciate ligament (arrow). (C) Arthroscopic findings of an avulsion fracture of the anterior cruciate ligament.
A
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B
Fig. 5. (A) A simple radiograph at the
five month follow-up shows accurate
reduction of the avulsion fracture and a
successful bony union. (B) Arthroscopic
finding at the 6th postoperative month
shows the healed avulsed bony fragment.
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Jin Wan Kim, et al. Cannulated screw fixation of ACL avulsion fracture
and magnetic resonance imaging (Fig. 4B), we observed a
Meyers-McKeever type III avulsion fracture. The dimension of the bone fragment was nearly 1.5 cm in length
and 1.2 cm in width. The surgery was performed 2 days
of the injury. Arthroscopically, we found that the avulsion
fracture fragment was completely separated from the ACL
attachment site (Fig. 4C). The fracture fragment was fixed
using a 4.0 mm cannulated screw, and care was taken to
avoid the physis of the proximal tibia. The postoperative
rehabilitation comprised a cylinder splint fixation and
partial weight-bearing for four weeks and a range of motion of 0o to 90o and full weight-bearing thereafter. At the
5-month follow-up, we found that the patient showed an
accurate reduction of the avulsion fracture and a successful bony union using simple radiography (Fig. 5A) and a
Lysholm knee score of 84. At the secondary arthroscopic
examination which we performed six months after
surgery, we found that the avulsed bony fragment was
completely healed (Fig. 5B), so the cannulated screw was
removed. No abnormal findings such as knee instability
or inhibition in motion were observed at the 8-month
follow-up.
DISCUSSION
Pediatric ACL avulsion fracture has been reported to frequently occur in individuals aged between 8 and 12 years.
Isolated ACL avulsion fractures accompanied by medial
collateral ligament and meniscal injuries usually occur as
a result of a hyperextension injury. Of the accompanying
meniscal injuries, lateral meniscal injuries in the marginal area have been often reported [4,9]. Kendall et al. [5]
reported that tibial spine fractures are accompanied by
a concomitant injury in 68% of cases, in both adults and
children. Clanton et al. [10] reported that the accompanying injury occurs more often in the meniscus, especially
in the lateral meniscus, than in other areas. Likewise, in
the case described in our study, we found a concomitant,
incomplete longitudinal tear in the posterior horn of the
lateral meniscus, which resolved with conservative treatment.
It is known that for the treatment of types I and II avul­
sion fractures, which are classified according to the
Meyers and Mckeever’s classification, a conservative
treatment is sufficient; whereas, for types III and IV, a
surgical treatment is required. But when a type II fracture with increased displacement switches to a type III
fracture, it has been found that reduction of the fragment
52
becomes difficult even with surgical treatment. Further,
in some cases where a bony union is achieved through
conservative treatment, chronic instability of the knee
may still persist. For these reasons, sometimes an early
surgical treatment is critical for a functional recovery of
the knee [7,9]. In the past, open surgery was the method
frequently performed for ACL avulsion fractures, but arthroscopic surgery has now replaced it because of its association with a swift recovery. Not only this, arthroscopy
is an invaluable tool in identifying and treating accompanying intra-articular lesions. Recently, various fixation
devices have been utilized during arthroscopic surgery
such as K-wires, pull-out suture, suture anchors, and cannulated screws. K-wires can be used to fix a fracture with
relative ease, but its disadvantages are that the strength
of fixation is relatively weak even when the fragment is
large enough and that they are difficult to use for a comminuted fracture. On the other hand, pull-out suture
or a suture anchor can be used to tightly fix small bone
fragments or a comminuted fracture, but it requires a
relatively complex surgical procedure. Cannulated screw
fixation has the advantages of expediting motion during
rehabilitation, having an easy surgical technique, and
providing a tight fixation. Delcogliano et al. [11] reported
that when the size of an avulsion is large enough, a screw
fixation is recommended because it provides the most
stable form of fixation. A large enough fragment for screw
insertion is deemed as a fragment of > 15 mm [12], which
can be a threshold used to judge whether an individual
with an ACL avulsion fracture should be indicated for
screw fixation or not. However, when a fracture fragment
is small or a comminuted, cannulated screw fixation cannot be used because the articular cartilage can be damaged by the screw thread during its insertion. In any case,
care must be taken to prevent articular damage resulting
from the procedure. Another disadvantage of screw fixation may be the need for a second surgical procedure to
remove the hardware, but this can be used for the benefit
of the patient by taking it as an opportunity to evaluate
bone healing and accompanying injuries.
Postoperative complications such as anterior instability of the knee and restricted extension after surgical
reduction have often been reported. Baxter and Wiley
[1] reported from their study on 45 cases of ACL avulsion fractures of more than three years of follow-up that,
though no patient complained of subjective instability of
the knee, anterior laxity was shown in 51% of the patients
after an anterior drawer test. They mentioned that ante-
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Jin Wan Kim, et al. Cannulated screw fixation of ACL avulsion fracture
rior laxity or a certain degree of restriction in extension
was inevitable because the thickening of the tibial spine
which disturbs the normal function of the ACL and is
accompanied by intraparenchymal damage of the ACL.
Grönkvist et al. [2] reported that loosening of the ACL
after union occurred in 33% of patients under 10 years
old and in 75% of patients over 10 years old. Also, they
reported that some compensation can be expected in
children regarding the compromised ACL, but as the age
increases, the degree of compensation declines. So they
recommended that the older the patient, the greater the
extent the ACL tension that should be recovered during
the surgery. In the two reported cases in our study, anterior laxity and restriction in extension were not observed.
In this study, we found favorable results at short-term
follow-up using cannulated screws for the arthroscopic
fixation of ACL avulsion fractures of the tibial spine.
CONFLICT OF INTEREST
No potential conflict of interest relevant to this article was
reported.
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