Percutaneous Navigation-Assisted Screw In Situ Fixation Of A Posterior-Wall Fracture Of The Acetabulum After Posterior Hip Dislocation: Case Report

¹Nobuyuki Kumahashi, ¹Kohei Naitou,¹Michihaya Kohno, ¹Masatoshi Tobita, ¹Kazushi Nishimura, 
²Yuji Uchio.

¹Department of Orthopedics, Ohda Municipal Hospital , 1428-3 Yoishinaga, Ohda, Ohda-shi, Shimane 694-0063, Japan.
²Department of Orthopedics, Shimane University School of Medicine, 89-1 Enya-cho, Izumo-shi, Shimane 693-8501, Japan.

Address for Correspondence:
N. Kumahashi
Department of Orthopedics, Ohda Municipal Hospital ,1428-3 Yoishinaga, Ohda, Ohda-shi, Shimane 694-0063, Japan.
Phone:   +81-854-82-0330
Fax    :   +81-854-84-7749
E-mail: n-kuma@med.shimane-u.ac.jp 

Abstract:

We report successful use of navigation-assisted screw fixation for an acetabular fracture. Our patient was a 52-year-old man who was in a motor vehicle accident, sustaining an open patella vertical fracture and minimally displaced acetabular fracture following posterior hip dislocation. First, we arthroscopically repaired the patellar fracture with three cannulated cortical screws.  We fixed the acetabular fracture with percutaneous fluoroscopic navigation assistance employing a 30-mm long cannulated cancellous screw. Bone union of the acetabulum was achieved three months after surgery, and the screws were removed nine months after the operation. No intraoperative complications, including nerve injury or bleeding, occurred.  Ｎo radiographic evidence of secondary fragment displacement or degenerative changes has been observed for follow-up forty months.  This patient’s satisfactory clinical outcome showed that percutaneous screw in situ fixation using a navigation system was a safe and minimally invasive way to treat this stable type of acetabular fracture. 

J.Orthopaedics 2009;6(2)e5

Keywords:

acetabular fracture; minimally invasive fixation; navigation-assisted surgery

Introduction:

Posterior wall fracture, the most common form of acetabular fracture, is often caused by high-energy trauma. The most important treatment for acetabular fracture is exact reduction of the acetabular dome, rigid fixation, and early rehabilitation ¹. Acetabular fracture is traditionally approached with conservative treatment; however, it is well known that 1 to 2 mm of displacement in reduction can lead to secondary osteoarthritis ^{2, 3}. Recently, surgery has become the gold standard treatment in cases of fragment displacement greater than 2 mm or fractures involving the weight-bearing dome ^{2, 3}. Surgical treatment of pelvic and acetabular fractures is technically difficult, even with percutaneous pelvic fixation, because of the great care needed to minimize risk of injury to the intrapelvic organs and neurovascular bundles. Image intensification is mandatory during percutaneous pelvic surgery to insert screws accurately and reduce intraoperative complications. Consequently, radiation exposure is increasing for both patients and surgical staff ⁴. Safe and accurate insertion of percutaneous screws requires fluoroscopy or three-dimensional reconstruction computed tomography (CT) scans with a computerized navigation system ^5,6,7,8.
Several computer navigation systems have been developed to improve the accuracy of aligning the components in total hip and knee replacement.  Some studies indicate that navigational assistance improves alignment accuracy compared with conventional techniques ^9,10.   Navigation systems have also facilitated treatment of acetabular fractures ^{5, 7,8}.  
We present a successful case of fluoroscopic navigation-assisted percutaneous screw in situ stabilization of a posterior-wall acetabular fracture after posterior dislocation.

Case Report:

A 52-year-old man who was injured in a car accident presented with right knee pain and right hip pain. There was an open patella fracture (GustiloⅠ) and an acetabular fracture (62 A1, AO classification, 3x2cm) secondary to posterior hip dislocation (Fig.1). On the day of injury, we repaired the right knee arthroscopically using three (length, 46, 48 and 50 mm) cannulated cortical screws; this was done under lumbar anesthesia. Four days after the first procedure, we osteosynthesized the posterior-wall acetabular fracture using navigation assisted surgery under lumbar anesthesia. Briefly, the patient was placed supine on a traction table.  The injured leg was positioned in neutral position. The other leg was positioned in 90° flexion and 30° abduction so we could easily use a C-arm.  In this case, since the minimal displacement (1 mm) of this fracture meant that we did not need to perform a reduction procedure, we used the navigation system for arthroplasty to assist percutaneous in situ fixation.  A single patient tracker pin (4 mm diameter) for the Stryker Imageless Navigation System (Stryker® LEIBINGER, Kalamazoo , MI ) was inserted into the right anterior superior iliac spine through a 1.5-cm skin incision.  Four preliminary fluoroscopic views (anteroposterior, lateral, and bilateral oblique views) were then obtained and calibrated into the system for placement of implants. The views were displayed simultaneously, and the ideal trajectory was chosen on all four views to verify safe screw placement (Fig.2). After satisfaction with an adequate direction for insertion of the drill pin, a 1.5-cm long skin incision was made and a drill guide pin (diameter, 1.6 mm) was passed according to the navigated line. The pointer was easy to put into the posterior hole of the drill reamer, and we could see the exact navigated blue line during drilling. Prior to insertion of the cannulated screw, the position of the guide wire was verified by fluoroscopy. A 4.0 mm cannulated cancellous screw (length, 30 mm) (ACE Japan Medical Dynamic Marketing, INC., Japan ) was passed over the drill guide after overdrilling.  A single screw fixation was the limitation of this case because of the small fragment (3x2cm).  Fixation was tightened, the guide pin was removed, and skin was sutured with Manipular after washing with saline (Fig.3). There was almost no bleeding. The fluoroscopic time was 1 minute and operative time was 57 minute.

Figure 1:  Preoperative X-ray films. White arrows indicate the fracture line.  (A) anteroposterior view. (B) oblique view.

Figure 2: Screen display as seen intraoperatively during screw insertion.  The position of the drill guide (in blue) is presented simultaneously on all four views to determine optimal trajectory for placement of the cannulated screw. The blue line indicates the virtual track of the guide wire. The fracture line is best seen in view (A). (A)R-oblique view. (B) anteroposterior view (C)lateral view (D)L-oblique view.

Figure 3: Postoperative X-ray films. White arrows indicate the cannulated cancellous screw.  (A) anteroposterior view. (B) oblique view.

Figure 4: Postoperative X-ray films (forty months after operation) following removal of the cannulated cancellous screw.  (A) anteroposterior view. (B) oblique view.

Continuous passive motion was started two weeks after hip repair.  Partial weight bearing was allowed at four weeks.  Full weight bearing was started at six weeks. Xp and CT imaging showed bone union three months postoperatively.  Subsequently, the screw head of the patella screw became painful, requiring its removal. Although we explained to the patient that the hip screw did not require removal, the patient elected to have both the knee and hip screws removed nine months after the operation.  During forty months of follow-up, no intraoperative or postoperative complications – including neurological defects, infection, osteonecrosis of the femoral head, fragment displacement, screw failure, or degenerative changes – have occurred (Fig 4). We rate the clinical outcome as satisfactory. 

Discussion :

Several reports of navigation-assisted fixation of acetabular fractures have been published. Crowl reported a series of nine patients with anterior column acetabular fractures who underwent percutaneous fixation using a virtual fluoroscopy surgical navigation system by Medtronic ¹¹. Clinical results were excellent, and there was a low degree of concern regarding anticipated late complications. Mosheiff reported on the percutaneous insertion of 45 cannulated screws in 29 patients (AO:61B1,2,3 C1,2 62A2,3 B1,2,3) with pelvic and acetabulum fractures, using a computerized fluoroscopic navigation system by Medtronic ⁷. Their accuracy of screw placement was 2 mm and 5°.  Since 2002, we have been using the Stryker Imageless Navigation System in total knee arthroplasties and in the treatment of greater trochanteric fractures, and the accuracy of its system have been proved ^9,10.  In the case report presented herein, because the fragment was small (3x2cm) and minimally displaced (62A1, AO classification), reduction was not needed.  Although this case might have been considered to fall outside of the range of indications for surgery, because the fracture involved the posterior wall and because the patient was middle-aged, we felt that surgical fixation was indicated in order to maintain the stability of the joint and prevent post-traumatic osteoarthritis ^2,3.  Use of the Navigation System not only facilitated accurate single screw fixation of the fracture fragment, but it also enabled us to treat the injury in a minimally-invasive manner by allowing us to forgo plating, which is the customary treatment for such injuries, helping us to achieve a good clinical result.  Had the displaced fragment required reduction, open reduction and rigid fixation of the fragment by plating would have been necessary.

There are some advantages of fixation of acetabular fractures using a navigation system. First, conventional methods involve high-radiation dosages for both patient and surgical staff. Use of navigation systems can reduce intraoperative radiation exposure (1minute). Second, this technology can reduce operative time (57 minutes). Third, the procedure was minimally invasive and bleeding loss was almost nonexistent. In our patient, only two 1.5-cm skin incisions were required, and pain was reduced postoperatively.

In a study by Carmack et al. analyzing errors in detecting inappropriate screw insertion using intraoperative fluoroscopy versus computed tomography, the authors noted that intraoperative fluoroscopy has the advantage of enabling intraoperative diagnosis of intra-articular screw penetration ¹².  In our case, we used four preliminary fluoroscopic views simultaneously during our fixation of a small bone fragment. None of the postoperative CT slices showed penetration of the acetabular dome, thereby confirming adequate fixation.

Percutaneous screw in situ fixation under fluoroscopic guidance proved to be a safe technique for treating our patient’s stable acetabular fracture that did not require reduction of the small bone fragment.  Our success suggests that percutaneous fixation under a navigation system also might be useful for treating non-displaced fragments resulting from other kinds of fractures.

Reference :

1. Helfet DL, Borrelli J, Di Pasquale T, Sanders R. (1992) Stabilization of acetabular fractures in elderly patients. J Bone Joint Surg Am;74:753-765.

2. Letournel E, Judet R (1993) Fractures of the acetabulum 2nd ed. Springer Verlag, Berlin.

3. Matta JM, Anderson LM, Epstein HC (1986) Fractures of the acetabulum. A retrospective analysis. Clin Orthop 205:230-240

4. Sanders R, Koval KJ, DiPaquale T, Schmelling G, Stenzler S, Ross E. (1993) Exposure of the orthopaedic surgeon to radiation. J Bone Joint Surg Am 75:326-330

5. Grützner, PA Rose E, Vock B (2002) Computer-assisted screw osteosynthesis of the posterior pelvic ring.  Initial experiences with an image reconstruction based on navigation system UnfallchirurgMar;105(3):254-260

6. Mouhsine E, Garofalo R, Borens O, Wettstein M, Blanc CH, Fisher JF, Moretti B, Leyvraz.PF (2005) Percutaneous retrogradescrewing for stabilisation of acetabular fractures. Injury 36(11):1330-1336

7. Mosheiff R, Khoury A , Weil Y, Liebergall M (2004) First generation computerized fluoroscopic navigation in percutaneous pelvic surgery. J Orthop Trauma Feb;18(2):106-111

8. Stuckl U, Konig B, Dahne M, Raschke M, Hass N. (2002) Computer assisted pelvic and acetabular surgery. Clinical experiences and indications.Unfallchirurg  Oct;105(10):886-89

9. Sparmann M, Wolke B, Czupalla D Banzer D (2003) Positioning of total knee arthroplasty with and without navigation support. J Bone Joint Surg Br 85:6:830-835

10. Stuckl B, Nogler M, Rosiek R, Fisher M, Krismer M, Ksssler O. (2004).  Navigation improves accuracy of rotational alignment in total knee arthroplasty.  Clin Orthop 426:180-186

11. Crowl AC, Kahler DM (2002) Closed reduction and percutaneous fixation of anterior column acetabular fractures. Comput Aided Surg 7(3):169-178

12. Carmack DB, Moed DH, McCarroll K, Freccero D. (2001) Accuracy of detecting screw penetration of the acetabulum using intraoperative fluoroscopy and computed tomography.  J Bone Joint Surg Am 83:1370-1375.

This is a peer reviewed paper 

Please cite as: N. Kumahashi: Percutaneous Navigation-Assisted Screw In Situ Fixation Of A Posterior-Wall Fracture Of The Acetabulum After Posterior Hip Dislocation: Case Report 

J.Orthopaedics 2009;6(2)e5

URL: http://www.jortho.org/2009/6/2/e5

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