|Year : 2016 | Volume
| Issue : 1 | Page : 23-28
Use of the Fassier-Duval telescopic rod for the management of congenital pseudarthrosis of the tibia
Mohammad Mesfer Alzahrani1, François Fassier2, Reggie C Hamdy2
1 Division of Orthopaedic Surgery, Shriners Hospital for Children, Montreal Children's Hospital, McGill University, Montreal, QC, Canada; Department of Orthopaedic Surgery, University of Dammam, Dammam, Saudi Arabia
2 Division of Orthopaedic Surgery, Shriners Hospital for Children, Montreal Children's Hospital, McGill University, Montreal, QC, Canada
|Date of Submission||29-Mar-2016|
|Date of Acceptance||28-Apr-2016|
|Date of Web Publication||17-May-2016|
Reggie C Hamdy
Shriners Hospital for Children, 1003 Decarie Blvd., Montreal, Quebec H4A0A9
Source of Support: None, Conflict of Interest: None
Introduction: Congenital pseudarthrosis of the tibia (CPT) is a rare condition that can pose a challenge in achieving union after surgical excision of the pseudarthrosis site. Multiple methods have been described for management of fractures complicating this abnormal bone, including intramedullary nails (IMNs) and external fixators. One of the IMN designs is the telescoping nail, which has many models including the Fassier-Duval (FD) rod. This system has been known for its use in the management of osteogenesis imperfecta and different types of dysplasia. In this series, we describe our experience with the use of this system in the management of CPT of the tibia in children.
Methods: We conducted a retrospective chart review of four patients with FD rod insertions for CPT management. The mean age at surgery was 7.6 years (range: 1.5-17) and the minimum follow-up was 20 months (average: 52.3 months, range: 20-93 months). Two out of the four patients had a concomitant diagnosis of neurofibromatosis Type 1.
Results: All four cases achieved union of the fracture at final follow-up. Complications encountered in these cases included a case of joint intrusion into the knee and a case of rod migration due to the failure of telescoping.
Conclusion: The FD rod showed promising results in our cohort, but before this treatment modality can be recommended for the management of CPT, additional studies are required.
Level of Evidence: IV
Keywords: Congenital pseudoarthrosis, Fassier-Duval rods, tibia
|How to cite this article:|
Alzahrani MM, Fassier F, Hamdy RC. Use of the Fassier-Duval telescopic rod for the management of congenital pseudarthrosis of the tibia. J Limb Lengthen Reconstr 2016;2:23-8
|How to cite this URL:|
Alzahrani MM, Fassier F, Hamdy RC. Use of the Fassier-Duval telescopic rod for the management of congenital pseudarthrosis of the tibia. J Limb Lengthen Reconstr [serial online] 2016 [cited 2019 Jan 20];2:23-8. Available from: http://www.jlimblengthrecon.org/text.asp?2016/2/1/23/182572
| Introduction|| |
Congenital pseudarthrosis of the tibia (CPT) and fibula is considered a rare pediatric orthopedic condition with an incidence ranging between 1/28,000 and 1/250,000. , This rare pathology poses a challenge to the orthopedic surgeon to achieve the desired union. This disorder, which was first described by Paget in 1891,  is defined as anterolateral bowing of the tibia due to an area of segmental dysplasia, thus leading to a nonunion when a fracture is sustained in that area.  Diagnosis is evident after the birth of the child, but antenatal ultrasound can detect tibial bowing in utero.  Plain radiographs confirm the diagnosis of CPT and magnetic resonance imaging can help evaluate soft tissues surrounding the pseudarthrosis site. 
Multiple classification systems have been described, based on the radiographic appearance, involvement of the fibula and presence of fracture at birth, but they provide only minimal prognostic value and should not be used to guide management planning. ,,, CPT is also associated with other diagnoses including neurofibromatosis (NF), fibrous dysplasia, and osteofibrous dysplasia. ,,,
Management goals can be divided into two-time points, before fracture and after fracture. When diagnosed before it fractures the main aim of management is protection of the affected tibia and potentially prevention of a fracture.  Bracing and casting have been recommended to prevent the bowed tibia from fracturing until skeletal maturity. Although this management option only prevented a fracture in a few reported cases, it still remains the main-stay of treatment at this stage. , Once a pseudarthrosis due to a fracture is established the goal of management becomes obtaining union, prevention of re-fracture and management of deformities and limb-length discrepancies. , To achieve these goals three components must be combined, these include: Pseudarthrosis excision, bone grafting, and adequate fixation. 
To the best of our knowledge, there has been only one case series that described the use of the Fassier-Duval (FD) rod in CPT with only two patients. Furthermore, we are aware of 2 other cases that were described in the literature. , Therefore, in our case series, we describe the use of the FD rod in the management of CPT in four patients that were managed at our center. As compared to conventional intramedullary nails (IMNs), FD rods have the ability of telescoping and thus, increase in length as the child grows. The construct does not have to cross the ankle joint to increase its stability as in conventional IMNs. With growth the rod slides from either end and reduces the stability at pseudarthrosis site, increasing the risk of re-fracture. ,
| Methods|| |
After obtaining Institutional Review Board approval from our institution, we conducted a retrospective chart review of four patients of FD rod insertions for CPT management. We analyzed these cases for demographics, treatment before telescoping rodding, complications and additional interventions, functional status, use of ambulatory aids and orthotics after surgery. Furthermore, X-rays were analyzed for assessing bone healing and deformity characteristics throughout the treatment. The four cases of tibial FD rod implantation were performed between October 2004 and September 2008 at our institute, with an average follow-up of 52.3 months (range: 20-93 months). Of the four patients, two patients had a concomitant diagnosis of NF-1. The mean age at surgery was 7.6 years (range: 1.5-17). Indications for surgery were increased tibial bow and fracture through the pseudarthrosis site. One patient (Case 4) underwent pseudarthrosis excision and Taylor spatial frame (TSF) application, after which the patient required a second surgery for FD insertion. In this patient, the indication for the FD rod was an enhancement of stability and protection of the excised pseudarthrosis area.
The surgical technique for insertion of FD rod is performed as described by Pega Medical, Quebec, Canada.  Nail diameter of the female component is measured according to anterior-posterior radiographs preoperatively. An incision is made over the site of the pseudarthrosis with the guidance of fluoroscopy and resection is done. Then, a medial parapatellar approach is performed with the patellar tendon retracted laterally and dissection is performed down to expose the proximal tibia. After which a K-wire is inserted into the tibial canal through a midline starting point [Figure 1]a. The reaming guide wire is inserted and reaming performed to the desired diameter. The male component is inserted and screwed into the distal epiphysis [Figure 1]b and c], next the female component (which is cut to the desired length) is placed over the male component and screwed into the proximal tibia. Then, the male component is cut and left protruding by 5 mm from the female component in the proximal tibia (or as limited by the proximal tibia cartilage) [Figure 1]d. Postoperatively all patients are prescribed a Sarmiento brace or full contact ankle-foot orthosis and allowed to partially weight bear. The brace is continued until radiographic evidence of healing at which point it is discontinued, and patients allowed to walk bearing full weight.
|Figure 1: Surgical technique for insertion of the tibial nail. (a) Through a standard anteromedial approach, the patellar tendon is retracted laterally and the prespinal, extra-articular surface of the tibial plateau is exposed. A small diameter K-wire is inserted antegrade with special attention not to bend the wire. Special reamers are used. (b) After performing the osteotomies, the male rod is inserted. (c) The male rod is centered in the middle of the epiphysis. (d) The male rod is cut and its smoothness checked to allow for telescoping. Hamdy RC, Fassier F. Case 85: Eleven-year-old child with osteogenesis imperfecta type III and multiple severe deformities, treated with telescoping Fassier-Duval rods. In: Limb Lengthening and Reconstruction Surgery Case Atlas. Switzerland: © Springer International Publishing; 2015. p. 611-7. (With permission of Springer)|
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- Case 1: 8-year-old male with left CPT and NF-1, managed with double (proximal and distal) tibial osteotomy, pseudarthrosis excision, FD rod insertion and osteogenic protein-1 (OP-1) graft. His postoperative course was complicated by proximal migration of the female nail and managed with revision and advancement of the rod [Figure 2]. The patient went on to have full union without any more complications. (This case was previously described in the literature) 
- Case 2: An 18-month-old male with right CPT, managed with pseudarthrosis excision, FD rod insertion, and OP-1 graft. Postoperatively, migration of the male component off the distal tibial epiphysis due to the failure of rod telescoping was observed but did not require additional surgery. The pseudarthrosis site fully united with no further complications [Figure 3]
- Case 3: A 4-year-old male with right CPT, managed with pseudarthrosis excision, FD rod insertion, and OP-1 graft. The patient had an uncomplicated postoperative course with adequate union [Figure 4]
- Case 4: A 17-year-old female with left CPT and NF-1. The CPT was managed 3 years before FD rod insertion with excision, iliac crest (IC) bone graft, and TSF application, which required a revision with OP-1 graft for nonunion. However, unfortunately, the nonunion persisted, leading to revision, pseudarthrosis excision, FD rod insertion (for enhanced stability and not for its telescoping role), IC and OP-1 graft. The patient went on to have full union without any complications.
|Figure 2: (a) At the age of 8 years, anteroposterior and lateral views showing a fracture at the middle - distal tibia and frank pseudarthrosis of the distal fibula. (b) Anteroposterior and lateral views of the tibia following a double-level osteotomy and internal fixation with a Fassier-Duval rod. (c) Anteroposterior and lateral views 4 months after the surgery, showing incomplete healing at both levels and protrusion of the female rod in the knee. (d) Two years and 5 months after the initial surgery, showing complete healing of both osteotomy sites. Hamdy RC, Fassier F. Case 29: Eight-year-old child with congenital pseudarthrosis tibia and severe deformity. Correction of deformity with double osteotomy, insertion of Fassier-Duval rod and OP-1 application. In: Limb Lengthening and Reconstruction Surgery Case Atlas. Switzerland: © Springer International Publishing; 2015. p. 197-202 (With permission of Springer)|
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|Figure 3: (a) Tibial anteroposterior and lateral views of an 18-month-old male diagnosed with congenital pseudarthrosis of the tibia. (b) Early postoperative Fassier-Duva l rod insertion X-rays. (c) Migration and nontelescoping of the Fassier-Duva l rod that was used to manage the congenital pseudarthrosis of the tibia in the same patient. The patient did not require a revision surgery due to adequate union at the fracture site|
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|Figure 4: (a) Anteroposterior and lateral views of the tibia in a 4 year-old-male diagnosed with congenital pseudarthrosis of the tibia. (b) Postoperative X-rays of the patient managed with Fassier-Duva rod insertion|
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| Results|| |
In our cases series, all four cases went on to have union of the fracture at final follow-up. At final follow-up three patients had a leg length discrepancy >2 cm [Table 1]. A form of regenerate enhancement was used in all patients, these included IC bone graft and OP-1 graft. Overall 2 out of the 4 cases had a complication in the postoperative period after the FD rod insertion procedure, these included 1 case of proximal migration of the female component [Figure 2] and [Table 2] and 1 case of rod migration due to nontelescoping [Figure 3] and [Table 2]. None of the cases were complicated by infection. None of the patients in our series required an amputation and none of the patients complained of pain or limitation in daily activities at final follow-up.
| Discussion|| |
Multiple designs for the telescoping nail are commercially available including the FD, Bailey-Dubow and Sheffield rods. These rods differ in the surgical technique from the FD rod system, which has the advantage of a single insertion site compared to the other systems. Concerning rate of re-operation, Fassier et al. and Birke et al. , reported a 14% and 13% rate of reoperation respectively with the use of the FD rods in osteogenesis imperfecta (OI) patients, whereas this rate was 21-32% with the Bailey-Dubow rods and 20% with the Sheffield rods. , Although our study is a small case series, we had no cases that required re-operation to obtain bone union.
The FD rod system consists of a female component (attached to the proximal epiphysis) and a male component (attached to the distal epiphysis) thus allowing telescoping of the rod as the child grows. In addition to the general advantages of the telescoping rods, including decreasing number and duration of operations required and bi-epiphyseal fixation, the FD-rods have an additional advantage over other telescoping rod designs (Bailey-Dubow and Sheffield rods) of a single proximal entry and improved epiphyseal fixation.Furthermore, this design omits the need for an arthrotomy at the knee or the ankle, as the insertions points are the greater trochanter in the femur and the prespinal area in the proximal tibia.  This design has been used for management of patients with OI and skeletal dysplasias to aid in long diaphyseal fractures, osteotomies, and nonunions. 
The rate of union following CPT treatment in the literature differs according to the type of fixation used. When using the IMN (including rush rods) the rate of union was 35-80% ,, and 96-98% using the Ilizarov technique or vascularized free fibular transfer. ,,,, In our very small case series, we achieved a 100% (4 out of 4) union rate with no persistent nonunion, but this union was achieved by also using other modalities, including biological enhancements (OP-1) and not by using the telescoping rod alone. Although the rate of the union is fairly similar to the Ilizarov frame (98% vs. 100%), it is crucial to keep in mind that compared to other management options the FD rods have the advantage of decreased operative time, decreased intra-operative blood loss and low complication in the postoperative course. ,
In our series, OP-1 (Stryker Biotech, Hopkinton, MA), which is also known as bone morphogenetic protein-7 (BMP-7), was used to enhance the healing process. This protein has been shown to improve healing rates when used in the context of nonunion, with healing rates ranging from 75% to 89%, but no long-term follow-up studies are available. , The use of BMP-7 has also been described in the context of CPT but only case series and reports are present in the literature. The largest case series was by Lee et al., which showed a healing rate of 20% (1/5 patients) when BMP-7 was used.  On the other hand, three case reports showed a 100% healing rate (3 patients) of the CPT when BMP was applied. ,, Dohin et al. also studied the effect of OP-1 on nonunion healing in children. They showed that healing occurred both clinically and radiographically in 17 out of 23 nonunions with two of the cases complicated by fractures.  In our present case series, no adverse reactions were encountered due the BMP application.
Although the FD rod design has multiple advantages when used in the appropriate setting, it also has its complications. The most common encountered complications are migration and failure of telescoping. Tapping and then insertion of the male component into distal epiphysis gives it a good purchase. This allows the sliding and telescoping mechanism to act, and also prevents migtration.  Furthermore, joint intrusion of the male component due to over reaming into the metaphysis and epiphysis is a fairly common complication, which can be prevented by reaming only past the isthmus.  In our cases, all patients had a full contact Sarmiento brace applied through the postoperative period or until the union of the fracture site was achieved.
A limitation of the FD rod is its inherent rotational instability. Casting of the operated limb until union is recommended for rotational control, but this technique may prevent early weight bearing and may be troublesome for the patient.  Another possible alternative is the use of an external fixation in addition to the telescoping rod, which can be removed when adequate bone healing has been identified, but this would also increase the rate of complications associated with the use of the external fixator.  In our cases, all patients had a full contact Sarmiento brace applied through the postoperative period or until the union of the fracture site was achieved.
In the literature, only one study by Birke et al.  reported on the outcome of two cases of CPT managed using the FD rod, both cases were associated with NF-1. The two patients required re-operation due to nonunion, also both cases were complicated by nontelescoping rod and joint intrusion. In their series, these patients only reached union when an Ilizarov frame was added for stabilization or exchange nail with plating was performed. Unfortunately, the surgical technique used in these cases was not explained in the manuscript as their main focus was on the use of the FD rod in the management of OI patients. Furthermore, other case reports were reported in the literature on the use of FD rods in CPT. ,
Limitations of our study include the retrospective nature of the series. Furthermore, the use of FD rods in the management of children with CPT is only one of several aspects of the surgical management of this condition. ,,, These aspects include excision of the pseudarthrosis site and surrounding hamartomatous tissue, limb re-alignment, stabilization of the long bone fragments (with internal fixation, external fixation or a combination of both internal and external fixation), biological enhancement of the pseudarthrosis site (with bone graft, BMPs, periosteal grafting, or possibly systemic bisphosphonates), cross union of the distal tibia with the fibula and IMN of the fibula. Therefore, it is very difficult to analyze accurately the effect of the FD rod alone.
| Conclusion|| |
We believe that the FD rod could be a viable adjunct in the management of cases with CPT. However, before this treatment modality can be recommended for the management of all cases of CPT, additional studies are required with a larger number of patients and long-term follow-up to adequately assess the safety and efficacy of this technique in this patient population.
Financial support and sponsorship
Conflicts of interest
Francois Fassier: Personal fees (royalties) from Pega Medical, during the conduct of the study.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2]