Arthroscopic fixation of chronic bicruciate tibial avulsion fractures: A case report

Abstract

A cruciate ligament avulsion is a much less common form of injury than a cruciate ligament tear. Simultaneous tibial avulsion fractures of both cruciate ligaments occur even more rarely. Over the last decades, many studies have described arthroscopic fixation of acute cruciate tibial avulsion fractures, but arthroscopic treatment in a late presenting patient has not been reported in the literature. This case report presents a 32-year-old female with a chronic tibial avulsion fracture of both anterior cruciate ligament and posterior cruciate ligament. Simultaneous fixation of both fractures was performed arthroscopically at week four post-injury. At one year of follow-up, the patient had demonstrated full knee range of motion and stable knee with no complaints, and achieved excellent clinical outcomes. Radiographs showed union of both fractures, and the patient had resumed high-impact exercises.

Introduction

Cruciate ligament injuries are mostly intrasubstance. Bony avulsion of either the anterior cruciate ligament (ACL) or posterior cruciate ligament (PCL) from its insertion is a significantly less common injury pattern.^1,2 Even rarer is the occurrence of concurrent tibial avulsion fractures of both cruciate ligaments.^3,4 Without proper treatment, these injuries cause instability of the knee joint and eventually degeneration of the knee joint.^2,5,6

The optimal surgical management of cruciate avulsion fractures remains controversial. Various open and arthroscopic techniques have been proposed for such injuries.^1,5,7 Arthroscopic treatment offers limited skin incisions, less soft tissue trauma, and faster recovery.⁸ Due to recent advances in the arthroscopic field, there have been many studies proposing different techniques to pursue simpler and more effective methods for the fixation of cruciate ligament avulsion fractures.⁸

The arthroscopic management of late presenting avulsion fracture of both ACL and PCL has not been described in the literature. Compared to acute treatment, chronic cases management presents additional technical challenges.9, 10, 11 This study aimed to describe a unique case of chronic bicruciate tibial avulsion fractures treated with arthroscopic fixation and report the outcome of our technique in an effort to discover the appropriate management for this infrequent scenario.

Case report

A 32-year-old female had a 3-week history of left knee pain and limping, after falling from the left side of her motorcycle and hitting the ground with her left knee bent. Physical examination demonstrated moderate swelling of the left knee. The patient could walk with a limp gait and tolerate a gentle knee range of motion (ROM) of 10° – 90°. She had no opening in the varus or valgus stress test. Further examination revealed a positive anterior-posterior drawer test, a positive Lachman test, and a negative dial test. The rest physical examinations were unremarkable.

Radiographic examination showed a displaced tibial eminence fracture and focal discontinuity of the PCL facet at the posterior tibia (Fig. 1). MRI of the knee revealed tibial avulsion fractures of both ACL and PCL with intact ligaments (Fig. 2). Both avulsions were classified as Meyers-McKeever type III. Arthroscopic fixation of both fractures was performed under regional anesthesia four weeks after injury.

Fig. 1.

Preoperative radiograph showing displaced avulsion fracture of both cruciate ligaments.

Fig. 2.

Preoperative MRI showing displaced avulsion fracture of ACL and PCL with intact ligaments.

Surgical technique

The patient was positioned supine with a tourniquet under the C-arm machine used to check for fracture reduction during the procedure. The arthroscopic diagnostic was performed through standard anterolateral and anteromedial portals. The examination of the joint revealed mild inflammation of synovium, intact meniscus, no cartilage defect, and intact but loose ACL (Fig. 3A). Debridement of the fracture bed was performed to allow complete reduction of fractures (Fig. 3B). The posteromedial and posterolateral trans-septal portals were established to work on the PCL facet.

Fig. 3.

Intraoperative arthroscopic views: (A) anterolateral portal view showing intact but loose ACL due to avulsed tibial eminence fracture; (B) debridement of the fracture bed using a spherical bur; (C) reduction of avulsed ACL fracture using the tip of tibial aimer device; (D) tight ACL after fixation of avulsed ACL fracture; (E) posteromedial portal view showing cortical button (arrow) maintaining the reduction of avulsed PCL fragment and (F) tight PCL after fixation of avulsed PCL fracture.

While the arthroscope was inserted through the posteromedial portal, a PCL tibial aiming device was used to reduce the avulsed PCL bone fragment through the anteromedial portal. A longitudinal incision was made anteromedially. A 2.4 mm drill-tip guide pin was drilled through the drill guide aimer to penetrate the avulsed bone fragment and some PCL fibers, followed by a 4.5 mm cannulated drill bit. Once the bone fragment was perforated, the guide wire was removed while the drill bit was retained to maintain the reduction of the fracture. A No. 0 monofilament suture was passed through the cannulated drill bit as a shuttle relay and was retrieved out of the posteromedial portal. A No. 5 high-strength suture was passed and tied to the rope of the suspensory cortical button. The device was passed into the posteromedial portal using the shuttle suture. Under arthroscopic visualization, the drill bit was removed and the suture was pulled out of the tibial tunnel so that the button maintained the reduction of the avulsed PCL bone fragment.

The arthroscope was then inserted back through the anterolateral portal. Using an 18-gauge needle, the ACL was punctured just above the bony fragment. A No. 0 monofilament suture was introduced through the needle into the joint as a shuttle relay, and its tip was grasped through the anteromedial portal. A No. 5 high-strength suture was tied to the end of the No. 0 suture, and the other end was pulled out so that the high-strength suture replaced the position of the needle. The avulsed tibial eminence fracture fragment was reduced using an ACL tibial angled drill guide (Fig. 3C). A 2.4 mm drill-tip guide pin was drilled from the anteromedial of the tibia to penetrate the avulsed bone fragment at a distance of 1 cm from the other tunnel, followed by a 4.5 mm cannulated drill bit. A No. 2 suture loop was inserted into the joint using the eyelet of the passing pin to retrieve the high-strength suture that has penetrated the ACL.

A 4.5 cortical screw with a washer is placed on the anteromedial side of the tibia, inferior to the tibial tunnel openings. The two high-strength sutures respectively from the tunnel originating from the ACL and PCL are pulled, tightened, and tied under the washer followed by tightening of the screw with the knee at 90° of flexion. Under arthroscopic evaluation, fracture reduction was shown to be stable over the ROM of the knee (Figs. 3D–F). The schematic drawing of the final fixation can be seen in Fig. 4.

Fig. 4.

Schematic drawing showing the fixation of the both avulsed fragments.

Postoperative management

The knee was braced in extension. The mobilization of isometric quadriceps and patella were performed immediately. The patient was allowed to fully support body weight with a brace locked in extension and axillary crutches to support balance in the first month. ROM exercises were initiated at week three, limited to 0° to 90°, then gradually increased over several weeks to achieve full flexion. Closed chained strengthening exercises were started at week six, when the patient was able to achieve full ROM of the knee and gradually increased to return to physical activities six months after surgery.

Follow-up

During 12 months of follow-up, no complications were found. The patient obtained full ROM at month three postoperatively (Fig. 5). The anterior-posterior drawer tests and Lachman tests were negative. Radiographic analysis showed that the fracture healed without displacement within three months after surgery (Fig. 6).

Fig. 5.

At month three of follow-up, the patient was able to squat.

Fig. 6.

Postoperative radiograph at month three of follow-up shows fracture union.

The patient had returned to preinjury physical activities within six months and was satisfied with the surgical outcome. She returned to playing badminton nine months after surgery. Both full scores of the Tegner-Lysholm score and the International Knee Documentation Committee score was achieved at the last follow-up, which had a significant improvement from the preoperative scores of 24 and 25.3, respectively.

Discussion

The cruciate ligaments have an important function in knee biomechanics. The interplay between ACL and PCL provides dynamic stability to the knee joint.¹² Avulsion fractures of cruciate ligaments will lead to knee instability, increased joint cartilage stress, and eventual caused articular degeneration.⁶ Based on the modified Meyers-McKeever classification, avulsion fractures of either ACL or PCL can be classified into four types: non-displaced avulsion fracture (type I), hinged avulsion fracture (type II), completely displaced avulsion fracture (type III), and comminuted avulsion fracture (type IV).¹³ Most experts believe that open or arthroscopic reduction and fixation are generally necessary for displaced fracture.²

Concurrent bicruciate avulsion fractures are an extremely rare condition. Such injuries have been reported in the literature as a result of motor vehicle accidents.^3,4,14 As with previous studies, the patient in our case was also a young adult who had a motorcycle accident. Calpur et al.⁴ reported an ipsilateral fracture of the femoral shaft and treated the patient with open surgery using cerclage wires to fix both avulsed fragments. Open reduction and screw fixation were procedures performed by de Souza Leão et al.³ to treat their patients, while arthroscopic fixation using an adjustable suspension device was reported in a recent study by Lombardo-Torre et al.¹⁴

Currently, arthroscopic fixation of cruciate avulsion fractures has become popular because of minimal skin incision and soft tissue injury.⁸ In addition, arthroscopy offers the ability to address additional intraarticular injuries during index procedures.^1,15 Techniques can differ, both in terms of the implants used to repair the fracture, such as a screw, Kirschner wire and sutures, and in the number of tunnels used, such as single tibial tunnel, Y-shaped tibial tunnel and double tibial tunnel.^5,16 Although various fixation and reduction techniques have been reported, the optimal methods remain controversial.^1,7

Suspensory button fixation has been shown to have good biomechanical properties and adequately restore posterior knee laxity in PCL avulsion fractures.^15,17 The first report of this technique demonstrated that the authors did not require multiple sutures and bony tunnels.¹⁸ Moreover, even if the fragments were too small, uniform compression can be achieved indirectly through extensive PCL tibial insertion. Recently, Zheng et al.⁵ also described the arthroscopic fixation of PCL tibial avulsion fractures using a cortical button. They used a longer suture loop to accommodate the tibial tunnel to prevent the risk of the suture being cut in the tunnel. We used a technique similar to that proposed by Wajsfisz et al.¹⁸ but utilized a cortical screw with a washer as a post-fixation method. In contrast to the technique described by Zheng et al.,⁵ we delivered the device into the joint through the posteromedial portal to avoid the ACL and PCL in the intercondylar notch which could block the passage of the button.

Compared with other devices, high-strength sutures and suture anchors can be used in fixation methods for ACL avulsion fractures regardless of fragment size. Their stiffness is comparable to or even greater to screw fixation. However, the usefulness in all types of fractures and the lower cost of sutures make it more suitable for use in developing countries.^8,19 Suture fixation techniques involve passing the suture through the ACL above its insertion. Depending on the techniques described, the number of fixation points on the ACL ranges from one to four.^8,16 To date, there is still no agreement on the optimal number of fixation points.^7,8,16 Concerning the number of tibial tunnels, Elsaid et al.⁷ only utilized one tibial tunnel to pull the sutures fixed to the ACL. This technique has been proven to be effective and faster. We applied a modified single-tunnel pullout suture technique with a high-strength suture punctured just above the avulsed fragment. Since another tunnel had been created for fixation of the avulsed PCL, a single tunnel to fix another avulsed cruciate fragment makes this technique less invasive and easier to perform.

Arthrofibrosis, decreased knee ROM, residual instability, and fracture nonunion are the most common complications following arthroscopic fixation of cruciate avulsion fractures. To reduce the risks, complete debridement of the fracture site and early rehabilitation are essential.^1,2,8,20 Bi et al.⁹ performed an autograft augmentation reconstruction in addition to suture fixation for delayed PCL avulsion fractures. According to them, the ability to achieve an anatomic reduction in chronic cases was relatively difficult. Despite the good clinical outcome and postoperative knee stability achieved, we believe that this technique is more invasive, complex, and time-consuming, especially in concurrent ACL and PCL avulsion fractures. In addition, we were able to obtain an anatomic reduction with optimal ligament tension after the removal of the fibrous tissue at the fracture site. Hence, we offer a simpler and less invasive method to treat this injury.

The advantages of our technique include its simplicity, less invasiveness, and cost-effectiveness. Moreover, it can be applied to simple or comminuted fractures regardless of the fragment size. However, it should be emphasized that the ultimate goal of the treatment of these injuries is the ability to achieve anatomic reduction and optimal ligament tension. Therefore, in cases of chronic cruciate avulsion fractures, the decision on whether this technique can be used should be made according to the intraoperative findings, in which the surgeon must be able to debride the fracture site properly to obtain a good reduction and proper ligament tension. In our experience, this technique provides excellent knee stability and clinical outcome for our patient.

Arthroscopic simultaneous fixation of late presenting bicruciate tibial avulsion fractures allows anatomic reduction and stable fixation with excellent clinical and functional outcomes. This technique may be used as a fixation method for chronic ACL and PCL tibial avulsion fractures.

Funding

Nil.

Ethical statement

The patient gave her consent to display information about herself related to the case report above to be displayed in a journal article.

Declaration of competing interest

None.

Author contributions

Glen Purnomo: conceptualization, investigation, writing – original draft, writing – review & editing, vizualisation. Aditya Fuad Robby Triangga: validation, writing – review & editing. Satrio Nugroho Magetsari: validation, writing – review & editing. Jansen Lee: validation, writing – review & editing. Jeffry Andrianus: resources, supervision, project administration.