Original article 291
Internal fixation after fracture or osteotomy of the femur in young children with polyostotic fibrous dysplasia Matteo Benedetti Valentini, Ernesto Ippolito, Francesco Catellani and Pasquale Farsetti Children from 4 to 7 years of age with polyostotic fibrous dysplasia (PFD) may need internal fixation of the femur for either fracture or osteotomy. At that age, the small size of the femur allows only the use of small intramedullary nails. However, titanium elastic nails and rigid intramedullary pediatric interlocking femoral nails – good for fracture or osteotomy fixation in the normal femur – are not indicated in PFD. From 2009 to 2011, we treated eight cases of PFD femoral fracture and deformity by internal fixation with a custom-modified adult humeral nail to which a spiral blade was connected. The 7-mm thick nail fit properly into the small femoral shaft and the spiral blade conferred ideal mechanical support to the femoral neck. Three cases had replacement of the humeral nail with a more appropriate
Introduction The femur is one of the first localizations of polyostotic fibrous dysplasia (PFD) in children. Limping, thigh pain, femoral fracture, and/or deformity are the clinical manifestations of the disease in young children 3–8 years of age. Surgical treatment by internal fixation is often required [1–8]. Peripheral plates are not recommended for surgical treatment owing to the high rate of complications, mostly represented by plate mobilization because of either screws loosening or fracture and deformity below the plate [1,6–9]. Intramedullary devices for children include titanium elastic nails (TENs) and rigid pediatric intramedullary nails. Both may be used in young children with small femurs, but several problems may arise during and after surgery in PFD [1–3,7–9]. The aim of our study is to present our medium-term experience with a custom-modified adult humeral nail that we used to stabilize either fractures or corrective osteotomies of the femur in young children with PFD.
Materials and methods From 2009 to 2011, we surgically treated five children with femoral deformity and/or fracture caused by PFD; their average age was 6 years (range: from 5 to 7 years). Four were boys and one was a girl. In three patients, both femurs were affected, whereas in two patients, femoral involvement was unilateral, for a total of eight operated cases. In all of them, the entire femur was affected by the disease, and in five femurs coxa vara ranging from 105° to 115° was associated with a shepherd’s crook deformity. Before surgery, all the patients were symptomatic, and
adult femoral nail 3 years after the index procedure when the femur had reached an adequate size. In the maximum follow-up period of 4 years, few complications were observed. J Pediatr Orthop B 24:291–295 Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved. Journal of Pediatric Orthopaedics B 2015, 24:291–295 Keywords: femoral osteotomy, internal fixation, intramedullary humeral nail, polyostotic fibrous dysplasia Department of Orthopaedic Surgery, University of Rome ‘Tor Vergata’, Rome, Italy Correspondence to Pasquale Farsetti, MD, Department of Orthopaedic Surgery, University of ‘Tor Vergata’ Rome, Viale Oxford, 81-00133 Rome, Italy Tel: + 39 335 5321530; fax: + 39 06 20903847; e-mail: [email protected]
had a painful limp. All the patients had already undergone previous surgery consisting of either intertrochanteric femoral osteotomy stabilized with a bladeplate or femoral elastic nailing or femoral shaft osteotomy stabilized with Kirschner wires and a plaster cast. Standing radiographs of the pelvis and lower limbs were taken before surgery as well as a computed tomographic (CT) scan of the femoral shaft at its narrowest point to verify the proper fit of the nail in the femoral shaft. At the time of surgery, the length of the eight femurs from the tip of the greater trochanter to the distal femoral growth plate ranged from 19 to 30 cm, with an average of 24.5 cm, whereas the body weight of the five patients ranged from a minimum of 14 kg to a maximum of 25 kg, with an average of 18 kg. For surgical stabilization of a fracture or corrective osteotomy, we used an intramedullary humeral nail (Expert-Synthes – Johnson and Johnson, Zuchwil, Switzerland) with a diameter of 7 mm and length ranging from 190 to 320 mm. The nail was custom-modified to provide 10° of proximal lateral bending to be introduced from the greater trochanter. A spiral blade 10 mm wide and ranging in length from 34 to 54 mm is connected to the proximal part of the nail to fit into the humeral head. In our cases, the spiral blade was used to properly stabilize the femoral neck, and it was positioned in all cases without crossing the proximal growth plate. One or two distal locking screws may also be applied to the nail in case of distal rotatory instability (Fig. 1). The ethical committee of our hospital provided written consent for the study.
1060-152X Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
DOI: 10.1097/BPB.0000000000000192
292 Journal of Pediatric Orthopaedics B 2015, Vol 24 No 4
Results
Fig. 1
Technical pitfalls
To fix femoral deformity, we performed three osteotomies in two cases, two osteotomies in three cases, and only one in three cases. In one case, fracture was associated with deformity. The diameter of the eight femurs, measured on CT scan sections taken at the narrowest point of the femoral shaft, ranged from 11.78 to 20.15 mm, with an average of 15.8 mm. We roughly calculated the ideal fit for the nail to be at least slightly less than one half of the entire femoral diameter at its narrowest point to avoid stress-shielding effects on the abnormal fibrodysplastic bone that fills up the entire femur, thereby causing severe thinning of the shaft cortex. We drilled a 9 mm wide canal in each fragment of the fibrodysplastic femur using a rigid guide to obtain a medullary canal 2 mm larger than the nail’s diameter, to facilitate sliding the humeral nail throughout the osteotomy fragments, and to decrease the risks of iatrogenic fracture of the osteotomy fragments. To confer sufficient support to the weak fibrodysplastic bone of the femoral neck, the spiral blade was inserted into the femoral neck through the slot present in the proximal part of the nail. The humeral nail was always positioned without intraoperative technical problems, and one distal locking screw conferred sufficient rotational stability to the implant (Figs 2 and 3). Follow-up
The length of follow-up ranged from 2 years and 3 months to 4 years and 2 months, with an average of 2 years and 11 months. All the patients were followed up every 5 months to assess both clinical and radiographic results. After the operation, all the children were kept in bed for 4 weeks until pain ceased, and then assisted weight-bearing was allowed with either crutches or a brace for a further 6 weeks. The osteotomies showed radiographic healing by the third month after the operation, when full weight-bearing was allowed. In all our patients, thigh pain disappeared and a progressive gait normalization was observed, with gradual improvement in or disappearance of the limp. At follow-up, a CT scan showed a complete radiographic remodeling of the fibrodysplastic bone around the nail without radiographic signs of bone resorption (Figs 2 and 3). In one case, there was painful mobilization of the distal locking screw that protruded against the fascia lata 6 months after surgery. The screw was removed without any further problem (Fig. 2).
The custom-modified Expert-Synthes – Johnson and Johnson humeral nail. The proximal part of the nail has been bent laterally 10° to be inserted from the greater trochanter into the femoral shaft.
In two other cases, there was a loss of the neck-shaft angle correction from 120° to 100° even though the spiral blade had been inserted into the lowest part of the femoral neck. In one of the two cases, the proximal part of the nail broke just below the spiral blade slot at the site
Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
Internal fixation in PFD Benedetti Valentini et al. 293
Fig. 2
(a)
(b)
(d)
(c)
15,68 mm
7,18 mm
(a) Five-year-old boy with McCune–Albright syndrome and extensive involvement of the right femur, with 70° coxa vara. (b) After correction of the coxa vara deformity and stabilization with a blade-plate, a custom-modified adult humeral nail was applied, with a cervical spiral blade and a distal locking screw that was removed later on. One osteotomy was performed 10 cm below the hip of the greater trochanter. (c) Three years later, a computed tomographic scan showed that the dysplastic bone had remodeled normally around the nail and the femur’s original diameter of 11.78 mm had increased up to 15.68 mm at its narrowest point. (d)The correction was maintained with evident distal femoral growth.
of a locking hole. Nail breakage was asymptomatic and it was discovered because the child developed a Trendelenburg limp because of a decrease of the neck-shaft angle. The broken humeral nail was replaced with a 9-mm thick adult femoral nail connected to a spiral blade (Fig. 3).
Discussion According to previous reports, there is general consensus on the use of intramedullary nails instead of peripheral plates for internal fixation of femoral fracture and/or corrective osteotomies in PFD [1–3,6–13]. It is well-known that the femur is one of the first PFD localizations, which usually becomes symptomatic within an age range of 3–12 years [7]. In older children with a large femoral shaft, 9-mm thick adult femoral intramedullary nails may be used, as we already reported
previously [12]. However, in younger children in the age range of 4–7 years, the femur is too small in size to host adult devices. TENs ranging in thickness from 2 to 4 mm could be used as an alternative [14,15], but in femurs diffusely affected by fibrous dysplasia, the absence of the medullary canal and the presence of a very thin cortex can make application of TENs very difficult owing to the likelihood of perforation. Moreover, TENs do not provide an internal stabilization strong enough to protect dysplastic bone against subsequent fractures and/or deformities [1]. Pediatric intramedullary interlocking nails ranging in diameter from 5.5 to 8.5 mm have been commercialized during the last few years [16–21]. However, these nails have been designed mainly for fractures, and they lack a
Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
294 Journal of Pediatric Orthopaedics B 2015, Vol 24 No 4
Fig. 3
(a) Seven-year-old boy with McCune–Albright syndrome. The right femur is diffusely affected by fibrous dysplasia and shepherd’s crook deformity is present, with a proximal shaft fracture. (b) Three osteotomies were performed to fix the deformity and a custom-modified humeral nail was used to stabilize the osteotomies. (c) One year and a half later, the osteotomies were healed and the neck-shaft angle measured 120°. (d) Two and a half years after the index operation, the boy had gained 15 kg of weight, the neck-shaft angle measured 100°, and the nail was broken at the site of a proximal locking hole. (e) Eight months after replacement of the broken humeral nail with an adult intramedullary interlocking nail.
valid cervical component to support the weak and large femoral neck that in many PFD cases misses the calcar. In those cases, the 4 to 5-mm thick cervical screws component available in some of the pediatric interlocking femoral nails cannot properly stabilize the femoral neck and cut-out of the cervical screws is likely to occur [22]. Examining the hardware armamentarium to be used in adult long bones smaller than the femur, we were positively impressed by the Expert humeral nail manufactured by Synthes – Johnson and Johnson that is specifically indicated in adults with a fragility fracture of the proximal humerus. In fact, the proximal part of the nail is connected to a spiral blade 10 mm wide, which ensures a very good purchase into the osteoporotic bone of the humeral head. We used this device in our cases by modifying the proximal part of the nail that was custombent laterally 10° to be properly inserted from the greater trochanter into the femoral shaft so as to avoid injury to the retinacular vessels of the fossa piriformis. Adult humeral nails have also been used in the past to fix children’s femoral fractures before specific pediatric femoral nails were manufactured [23]. Our preliminary results are very encouraging. The families of our young patients were very keen to provide their informed consent to implant the custom-modified
humeral nail in their children’s femur once they understood that the only alternatives were either TENs, with all their limitations, or standard pediatric femoral nails lacking a valid support for the weak femoral neck. Although the femoral neck had been stabilized with the spiral blade, the neck-shaft angle lost 20° of correction in two cases (37%), showing how difficult it can be to stabilize the neck-shaft angle in some PFD cases with severe involvement of the femoral neck. We believe that, to improve the femoral neck stabilization, new designs of cervicodiaphyseal nails are needed. In the present series, we never crossed the proximal growth plate of the femur with the cervical blade. However, crossing the growth plate to achieve better fixation may be considered in children older than 10 years. We are aware of all the limitations of our study. The first limitation is the custom modification of the original device. The custom modification was made by heating the proximal part of the nail at melting temperature to obtain 10° of lateral bending. No mechanical tests were performed, but we never observed nail break at the site of the bending, although theoretically, proximal lateral bending might have weakened the nail. However, in one case, the nail broke at the site of a proximal locking hole
Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
Internal fixation in PFD Benedetti Valentini et al. 295
rather than at the level of the custom-made angulation. We believe that in that case, the increase in his body weight might have been an important concurrent factor because that child was the heaviest in the entire series. The second limitation is the need to replace the humeral nail with an adult femoral interlocking nail as soon as the child grows up and the nail becomes insufficient for the increase in the size of the femur and the increase in body weight. This is a well-known problem in growing children with bone fragility, and one attempted solution has been the application of self-elongating telescopic intramedullary nails [24,25]. However, those nails may protect the femoral shaft from fractures, but the neck-shaft angle cannot be stabilized, as shown by O’Sullivan and Zacharin [26], who applied Sheffield elongating rods in five children with McCune–Albright syndrome.
9
10
11
12
13
14
15
Conclusion
We believe that a proximal humeral nail connected to a spiral blade may represent a very useful device to fix femoral fracture and deformity in PFD within a circumscribed age range in which no other valid alternative is currently available.
16
Acknowledgements
18
17
Conflicts of interest
There are no conflicts of interest.
19
References 1 Ippolito E, Bray EW, Corsi A, de Maio F, Exner UG, Robey PG, et al. European Pediatric Orthopaedic Society. Natural history and treatment of fibrous dysplasia of bone: a multicenter clinicopathologic study promoted by the European Pediatric Orthopaedic Society. J Pediatr Orthop B 2003; 12:155–177. 2 DiCaprio MR, Enneking WF. Fibrous dysplasia. pathophysiology, evaluation, and treatment. J Bone Joint Surg Am 2005; 87:1848–1864. 3 Stanton RP. Surgery for fibrous dysplasia. J Bone Miner Res 2006; 21 (Suppl 2):105–109. 4 Leet AI, Wientroub S, Kushner H, Brillante B, Kelly MH, Robey PG, Collins MT. The correlation of specific orthopaedic features of polyostotic fibrous dysplasia with functional outcome scores in children. J Bone Joint Surg Am 2006; 88:818–823. 5 Hart ES, Kelly MH, Brillante B, Chen CC, Ziran N, Lee JS, et al. Onset, progression, and plateau of skeletal lesions in fibrous dysplasia and the relationship to functional outcome. J Bone Miner Res 2007; 22:1468–1474. 6 Leet AI, Collins MT. Current approach to fibrous dysplasia of bone and McCune–Albright syndrome. J Child Orthop 2007; 1:3–17. 7 Stanton RP, Ippolito E, Springfield D, Lindaman L, Wientroub S, Leet A. The surgical management of fibrous dysplasia of bone. Orphanet J Rare Dis 2012; 7 (Suppl 1):S1. 8 Stanton RP, Diamond L. Surgical management of fibrous dysplasia in McCun–Albright syndrome. Pediatr Endocrinol Rev 2007; 4 (Suppl 4): 446–452.
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Ippolito E, Farsetti P, Boyce AM, Corsi A, de Maio F, Collins MT. Radiographic classification of coronal plane femoral deformities in polyostotic fibrous dysplasia. Clin Orthop Relat Res 2014; 472:1558–1567. Keijser LC, van Tienen TG, Schreuder HW, Lemmens JA, Pruszczynski M, Veth RP. Fibrous dysplasia of bone: management and outcome of 20 cases. J Surg Oncol 2001; 76:157–166. discussion 167–168. Freeman BH, Bray EW 3rd, Meyer LC. Multiple osteotomies with Zickel nail fixation for polyostotic fibrous dysplasia involving the proximal part of the femur. J Bone Joint Surg Am 1987; 69:691–698. Ippolito E, Caterini R, Farsetti P, Potenza V. Surgical treatment of fibrous dysplasia of bone in McCune–Albright syndrome. J Pediatr Endocrinol Metab 2002; 15 (Suppl 3):939–944. Yang L, Jing Y, Hong D, Chong-qi T. Valgus osteotomy combined with intramedullary nail for Shepherd’s crook deformity in fibrous dysplasia: 14 femurs with a minimum of 4 years follow-up. Arch Orthop Trauma Surg 2010; 130:497–502. Lascombes P, Haumont T, Journeau P. Use and abuse of flexible intramedullary nailing in children and adolescents. J Pediatr Orthop 2006; 26:827–834. Lascombes P, Nespola A, Poircuitte JM, Popkov D, de Gheldere A, Haumont T, Journeau P. Early complications with flexible intramedullary nailing in childhood fracture: 100 cases managed with precurved tip and shaft nails. Orthop Traumatol Surg Res 2012; 98:369–375. Jencikova-Celerin L, Phillips JH, Werk LN, Wiltrout SA, Nathanson I. Flexible interlocked nailing of pediatric femoral fractures: experience with a new flexible interlocking intramedullary nail compared with other fixation procedures. J Pediatr Orthop 2008; 28:864–873. Keeler KA, Dart B, Luhmann SJ, Schoenecker PL, Ortman MR, Dobbs MB, Gordon JE. Antegrade intramedullary nailing of pediatric femoral fractures using an interlocking pediatric femoral nail and a lateral trachanteric entry point. J Pediatr Orthop 2009; 29:345–351. Garner MR, Bhat SB, Khujanazarov I, Flynn JM, Spiegel D. Fixation of lengthstable femoral shaft fractures in heavier children: flexible nails vs rigid locked nails. J Pediatr Orthop 2011; 31:11–16. Miller DJ, Kelly DM, Spence DD, Beaty JH, Warner WC Jr, Sawyer JR. Locked intramedullary nailing in the treatment of femoral shaft fractures in children younger than 12 years of age: indications and preliminary report of outcomes. J Pediatr Orthop 2012; 32:777–780. Reynolds RA, Legakis JE, Thomas R, Slongo TF, Hunter JB, Clavert JM. Intramedullary nails for pediatric diaphyseal femur fractures in older, heavier children: early results. J Child Orthop 2012; 6:181–188. Crosby SN Jr. Twenty year experience with rigid intramedullary nailing of femoral shaft fractures in skeletally immature patients. J Bone Joint Surgery Am 2014; 96:1080–1089. Ippolito E, Farsetti P, Benedeti Valentini M, Potenza V. Two-stage surgical treatment of complex femoral deformities with severe coxa vara in polyostotic fibrous dysplasia. J Bone Joint Surg Am 2015; 97:119–125. Gordon JE, Khanna N, Luhmann SJ, Dobbs MB, Ortman MR, Schoenecker PL. Intramedullary nailing of femoral fractures in children through the lateral aspect of the greater trochanter using a modified rigid humeral intramedullary nail: preliminary results of a new technique in 15 children. J Orthop Trauma 2004; 18:416–422. discussion 423–424. Birke O, Davies N, Latimer M, Little DG, Bellemore M. Experience with the Fassier–Duval telescopic rod: first 24 consecutive cases with a minimum of 1-year follow-up. J Pediatr Orthop 2011; 31:458–464. Lee K, Park S, Yoo WJ, Chung CY, Choi H, Cho TJ. Proximal migration of femoral telescopic rod in children with osteogenesis imperfecta. J Pediatr Orthop 2015; 35:178–184. O’Sullivan M, Zacharin M. Intramedullary rodding and bisphosphonate treatment of polyostotic fibrous dysplasia associated with the McCune–Albright syndrome. J Pediatr Orthop 2002; 22:255–260.
Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
Internal fixation after fracture or osteotomy of the femur in young children with polyostotic fibrous dysplasia Matteo Benedetti Valentini, Ernesto Ippolito, Francesco Catellani and Pasquale Farsetti Children from 4 to 7 years of age with polyostotic fibrous dysplasia (PFD) may need internal fixation of the femur for either fracture or osteotomy. At that age, the small size of the femur allows only the use of small intramedullary nails. However, titanium elastic nails and rigid intramedullary pediatric interlocking femoral nails – good for fracture or osteotomy fixation in the normal femur – are not indicated in PFD. From 2009 to 2011, we treated eight cases of PFD femoral fracture and deformity by internal fixation with a custom-modified adult humeral nail to which a spiral blade was connected. The 7-mm thick nail fit properly into the small femoral shaft and the spiral blade conferred ideal mechanical support to the femoral neck. Three cases had replacement of the humeral nail with a more appropriate
Introduction The femur is one of the first localizations of polyostotic fibrous dysplasia (PFD) in children. Limping, thigh pain, femoral fracture, and/or deformity are the clinical manifestations of the disease in young children 3–8 years of age. Surgical treatment by internal fixation is often required [1–8]. Peripheral plates are not recommended for surgical treatment owing to the high rate of complications, mostly represented by plate mobilization because of either screws loosening or fracture and deformity below the plate [1,6–9]. Intramedullary devices for children include titanium elastic nails (TENs) and rigid pediatric intramedullary nails. Both may be used in young children with small femurs, but several problems may arise during and after surgery in PFD [1–3,7–9]. The aim of our study is to present our medium-term experience with a custom-modified adult humeral nail that we used to stabilize either fractures or corrective osteotomies of the femur in young children with PFD.
Materials and methods From 2009 to 2011, we surgically treated five children with femoral deformity and/or fracture caused by PFD; their average age was 6 years (range: from 5 to 7 years). Four were boys and one was a girl. In three patients, both femurs were affected, whereas in two patients, femoral involvement was unilateral, for a total of eight operated cases. In all of them, the entire femur was affected by the disease, and in five femurs coxa vara ranging from 105° to 115° was associated with a shepherd’s crook deformity. Before surgery, all the patients were symptomatic, and
adult femoral nail 3 years after the index procedure when the femur had reached an adequate size. In the maximum follow-up period of 4 years, few complications were observed. J Pediatr Orthop B 24:291–295 Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved. Journal of Pediatric Orthopaedics B 2015, 24:291–295 Keywords: femoral osteotomy, internal fixation, intramedullary humeral nail, polyostotic fibrous dysplasia Department of Orthopaedic Surgery, University of Rome ‘Tor Vergata’, Rome, Italy Correspondence to Pasquale Farsetti, MD, Department of Orthopaedic Surgery, University of ‘Tor Vergata’ Rome, Viale Oxford, 81-00133 Rome, Italy Tel: + 39 335 5321530; fax: + 39 06 20903847; e-mail: [email protected]
had a painful limp. All the patients had already undergone previous surgery consisting of either intertrochanteric femoral osteotomy stabilized with a bladeplate or femoral elastic nailing or femoral shaft osteotomy stabilized with Kirschner wires and a plaster cast. Standing radiographs of the pelvis and lower limbs were taken before surgery as well as a computed tomographic (CT) scan of the femoral shaft at its narrowest point to verify the proper fit of the nail in the femoral shaft. At the time of surgery, the length of the eight femurs from the tip of the greater trochanter to the distal femoral growth plate ranged from 19 to 30 cm, with an average of 24.5 cm, whereas the body weight of the five patients ranged from a minimum of 14 kg to a maximum of 25 kg, with an average of 18 kg. For surgical stabilization of a fracture or corrective osteotomy, we used an intramedullary humeral nail (Expert-Synthes – Johnson and Johnson, Zuchwil, Switzerland) with a diameter of 7 mm and length ranging from 190 to 320 mm. The nail was custom-modified to provide 10° of proximal lateral bending to be introduced from the greater trochanter. A spiral blade 10 mm wide and ranging in length from 34 to 54 mm is connected to the proximal part of the nail to fit into the humeral head. In our cases, the spiral blade was used to properly stabilize the femoral neck, and it was positioned in all cases without crossing the proximal growth plate. One or two distal locking screws may also be applied to the nail in case of distal rotatory instability (Fig. 1). The ethical committee of our hospital provided written consent for the study.
1060-152X Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
DOI: 10.1097/BPB.0000000000000192
292 Journal of Pediatric Orthopaedics B 2015, Vol 24 No 4
Results
Fig. 1
Technical pitfalls
To fix femoral deformity, we performed three osteotomies in two cases, two osteotomies in three cases, and only one in three cases. In one case, fracture was associated with deformity. The diameter of the eight femurs, measured on CT scan sections taken at the narrowest point of the femoral shaft, ranged from 11.78 to 20.15 mm, with an average of 15.8 mm. We roughly calculated the ideal fit for the nail to be at least slightly less than one half of the entire femoral diameter at its narrowest point to avoid stress-shielding effects on the abnormal fibrodysplastic bone that fills up the entire femur, thereby causing severe thinning of the shaft cortex. We drilled a 9 mm wide canal in each fragment of the fibrodysplastic femur using a rigid guide to obtain a medullary canal 2 mm larger than the nail’s diameter, to facilitate sliding the humeral nail throughout the osteotomy fragments, and to decrease the risks of iatrogenic fracture of the osteotomy fragments. To confer sufficient support to the weak fibrodysplastic bone of the femoral neck, the spiral blade was inserted into the femoral neck through the slot present in the proximal part of the nail. The humeral nail was always positioned without intraoperative technical problems, and one distal locking screw conferred sufficient rotational stability to the implant (Figs 2 and 3). Follow-up
The length of follow-up ranged from 2 years and 3 months to 4 years and 2 months, with an average of 2 years and 11 months. All the patients were followed up every 5 months to assess both clinical and radiographic results. After the operation, all the children were kept in bed for 4 weeks until pain ceased, and then assisted weight-bearing was allowed with either crutches or a brace for a further 6 weeks. The osteotomies showed radiographic healing by the third month after the operation, when full weight-bearing was allowed. In all our patients, thigh pain disappeared and a progressive gait normalization was observed, with gradual improvement in or disappearance of the limp. At follow-up, a CT scan showed a complete radiographic remodeling of the fibrodysplastic bone around the nail without radiographic signs of bone resorption (Figs 2 and 3). In one case, there was painful mobilization of the distal locking screw that protruded against the fascia lata 6 months after surgery. The screw was removed without any further problem (Fig. 2).
The custom-modified Expert-Synthes – Johnson and Johnson humeral nail. The proximal part of the nail has been bent laterally 10° to be inserted from the greater trochanter into the femoral shaft.
In two other cases, there was a loss of the neck-shaft angle correction from 120° to 100° even though the spiral blade had been inserted into the lowest part of the femoral neck. In one of the two cases, the proximal part of the nail broke just below the spiral blade slot at the site
Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
Internal fixation in PFD Benedetti Valentini et al. 293
Fig. 2
(a)
(b)
(d)
(c)
15,68 mm
7,18 mm
(a) Five-year-old boy with McCune–Albright syndrome and extensive involvement of the right femur, with 70° coxa vara. (b) After correction of the coxa vara deformity and stabilization with a blade-plate, a custom-modified adult humeral nail was applied, with a cervical spiral blade and a distal locking screw that was removed later on. One osteotomy was performed 10 cm below the hip of the greater trochanter. (c) Three years later, a computed tomographic scan showed that the dysplastic bone had remodeled normally around the nail and the femur’s original diameter of 11.78 mm had increased up to 15.68 mm at its narrowest point. (d)The correction was maintained with evident distal femoral growth.
of a locking hole. Nail breakage was asymptomatic and it was discovered because the child developed a Trendelenburg limp because of a decrease of the neck-shaft angle. The broken humeral nail was replaced with a 9-mm thick adult femoral nail connected to a spiral blade (Fig. 3).
Discussion According to previous reports, there is general consensus on the use of intramedullary nails instead of peripheral plates for internal fixation of femoral fracture and/or corrective osteotomies in PFD [1–3,6–13]. It is well-known that the femur is one of the first PFD localizations, which usually becomes symptomatic within an age range of 3–12 years [7]. In older children with a large femoral shaft, 9-mm thick adult femoral intramedullary nails may be used, as we already reported
previously [12]. However, in younger children in the age range of 4–7 years, the femur is too small in size to host adult devices. TENs ranging in thickness from 2 to 4 mm could be used as an alternative [14,15], but in femurs diffusely affected by fibrous dysplasia, the absence of the medullary canal and the presence of a very thin cortex can make application of TENs very difficult owing to the likelihood of perforation. Moreover, TENs do not provide an internal stabilization strong enough to protect dysplastic bone against subsequent fractures and/or deformities [1]. Pediatric intramedullary interlocking nails ranging in diameter from 5.5 to 8.5 mm have been commercialized during the last few years [16–21]. However, these nails have been designed mainly for fractures, and they lack a
Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
294 Journal of Pediatric Orthopaedics B 2015, Vol 24 No 4
Fig. 3
(a) Seven-year-old boy with McCune–Albright syndrome. The right femur is diffusely affected by fibrous dysplasia and shepherd’s crook deformity is present, with a proximal shaft fracture. (b) Three osteotomies were performed to fix the deformity and a custom-modified humeral nail was used to stabilize the osteotomies. (c) One year and a half later, the osteotomies were healed and the neck-shaft angle measured 120°. (d) Two and a half years after the index operation, the boy had gained 15 kg of weight, the neck-shaft angle measured 100°, and the nail was broken at the site of a proximal locking hole. (e) Eight months after replacement of the broken humeral nail with an adult intramedullary interlocking nail.
valid cervical component to support the weak and large femoral neck that in many PFD cases misses the calcar. In those cases, the 4 to 5-mm thick cervical screws component available in some of the pediatric interlocking femoral nails cannot properly stabilize the femoral neck and cut-out of the cervical screws is likely to occur [22]. Examining the hardware armamentarium to be used in adult long bones smaller than the femur, we were positively impressed by the Expert humeral nail manufactured by Synthes – Johnson and Johnson that is specifically indicated in adults with a fragility fracture of the proximal humerus. In fact, the proximal part of the nail is connected to a spiral blade 10 mm wide, which ensures a very good purchase into the osteoporotic bone of the humeral head. We used this device in our cases by modifying the proximal part of the nail that was custombent laterally 10° to be properly inserted from the greater trochanter into the femoral shaft so as to avoid injury to the retinacular vessels of the fossa piriformis. Adult humeral nails have also been used in the past to fix children’s femoral fractures before specific pediatric femoral nails were manufactured [23]. Our preliminary results are very encouraging. The families of our young patients were very keen to provide their informed consent to implant the custom-modified
humeral nail in their children’s femur once they understood that the only alternatives were either TENs, with all their limitations, or standard pediatric femoral nails lacking a valid support for the weak femoral neck. Although the femoral neck had been stabilized with the spiral blade, the neck-shaft angle lost 20° of correction in two cases (37%), showing how difficult it can be to stabilize the neck-shaft angle in some PFD cases with severe involvement of the femoral neck. We believe that, to improve the femoral neck stabilization, new designs of cervicodiaphyseal nails are needed. In the present series, we never crossed the proximal growth plate of the femur with the cervical blade. However, crossing the growth plate to achieve better fixation may be considered in children older than 10 years. We are aware of all the limitations of our study. The first limitation is the custom modification of the original device. The custom modification was made by heating the proximal part of the nail at melting temperature to obtain 10° of lateral bending. No mechanical tests were performed, but we never observed nail break at the site of the bending, although theoretically, proximal lateral bending might have weakened the nail. However, in one case, the nail broke at the site of a proximal locking hole
Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
Internal fixation in PFD Benedetti Valentini et al. 295
rather than at the level of the custom-made angulation. We believe that in that case, the increase in his body weight might have been an important concurrent factor because that child was the heaviest in the entire series. The second limitation is the need to replace the humeral nail with an adult femoral interlocking nail as soon as the child grows up and the nail becomes insufficient for the increase in the size of the femur and the increase in body weight. This is a well-known problem in growing children with bone fragility, and one attempted solution has been the application of self-elongating telescopic intramedullary nails [24,25]. However, those nails may protect the femoral shaft from fractures, but the neck-shaft angle cannot be stabilized, as shown by O’Sullivan and Zacharin [26], who applied Sheffield elongating rods in five children with McCune–Albright syndrome.
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Conclusion
We believe that a proximal humeral nail connected to a spiral blade may represent a very useful device to fix femoral fracture and deformity in PFD within a circumscribed age range in which no other valid alternative is currently available.
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Acknowledgements
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Conflicts of interest
There are no conflicts of interest.
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