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Treatment of shepherd ’ s crook deformity in patients with polyostotic fibrous dysplasia using a new type of custom made retrograde intramedullary nail: a technical note

View Article: PubMed Central - PubMed

ABSTRACT

Aims: The severe form of coxa vara, the ‘shepherd’s crook deformity’, is always a consequence of a locally extensive form of polyostotic fibrous dysplasia (or McCune-Albright syndrome). Treatment of this deformity is a challenge. The soft bone does not tolerate any implant that depends on the stability of the cortical bone (like plates or external fixators). Intramedullary nails are the most appropriate implants for stabilisation, but if they are inserted from the greater trochanter, they cannot correct the varus deformity enough.

Patients and methods: We have developed a special intramedullary nail that can be inserted from the osteotomy site and can be driven retrograde into the femoral neck in an appropriate valgus position. We have operated 15 legs in 13 patients. The average age at surgery was 14 years and 5 months (6 to 28.9). In all, 11 femora had been operated before (unsuccessfully) with various implants.

Results: The average follow-up was 54.2 months (7 to 132). The average correction of the neck/(distal) shaft angle was 57.5° (10° to 80°) ( = 72.8%). While pre-operatively none of the patients was able to walk without aid, at follow-up only one patient was unable to walk, three used the aid of crutches because of tibial lesions and one patient had an increased external rotation of the leg. At follow-up, most patients were free of pain. One implant broke and had to be replaced.

Conclusion: This new operative method offers the possibility of efficient correction and stabilisation of this severe and difficult deformation.

No MeSH data available.


Related in: MedlinePlus

(a) Three-dimensional reconstructions of CT scans (frontal view) of a 10.7-year-old boy (cases 12 and 13) with polyostotic fibrous dysplasia und shepherd’s crook deformation of the femur. (b) AP radiographs three months post-operatively after correction with multiple osteotomies and stabilisation with telescopic retrograde intramedullary nail and two femoral neck screws on both sides.
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Figure 6: (a) Three-dimensional reconstructions of CT scans (frontal view) of a 10.7-year-old boy (cases 12 and 13) with polyostotic fibrous dysplasia und shepherd’s crook deformation of the femur. (b) AP radiographs three months post-operatively after correction with multiple osteotomies and stabilisation with telescopic retrograde intramedullary nail and two femoral neck screws on both sides.

Mentions: Pre-operative planning was performed on orthogonal plain radiographs which produced a template that showed the degree of bony resection, correction required and likely position of the intramedullary nail. From this information, a custom-made nail was made for each case by Synthes Switzerland (Fig. 3). In surgery, the patient is placed in a supine position with slight elevation of the affected side. A direct lateral approach is made to the femur which is exposed carefully subperiosteally. A 2.5-mm Kirschner wire is introduced from the lateral cortex down the femoral neck in a central location to guide the alignment of the osteotomy. The osteotomy is made and enough bone resected to allow the deformity to be fully corrected. The distal canal is then opened with a straight reamer and if any lateral bowing is present this must be fully corrected with one or more additional osteotomies. In the growing child, a smaller male component is first placed into the medullary canal with a special T-handle. This is placed across the distal femoral physis and locked with a transverse small fragment screw (Figs 4 to 6). The female nail is then passed over the male and made flush with the cut end of the femur. For adolescents or adults, the central telescoping part is not needed. A window is made in the lateral cortex of the femur to give access to the mid part of the nail that has a series of ridges. With the deformity completely corrected, the nail can then be advanced in a retrograde fashion using a small punch inclined against the ridges. With this retrograde method, the proximal end of the nail can be inserted as medial as necessary; if it is appropriate it can even be brought to the metaphysis (Fig. 5) or even into the femoral head. Small holes in the nail at regular distances in the axis of the femoral neck screws help to maintain the orientation of the nail while hammering proximally. For the insertion of the femoral neck screws and the bolting screw in the distal epiphysis, a 3Dimage intensifier is very helpful, as the bone is very thin and axial views cannot be made before the insertion of the proximal screws, because with the leverage the nail would enlarge the hole within the soft bone. At the end of the operation, the correct rotation is secured with K-wires through the cortices of both fragments of the osteotomy.


Treatment of shepherd ’ s crook deformity in patients with polyostotic fibrous dysplasia using a new type of custom made retrograde intramedullary nail: a technical note
(a) Three-dimensional reconstructions of CT scans (frontal view) of a 10.7-year-old boy (cases 12 and 13) with polyostotic fibrous dysplasia und shepherd’s crook deformation of the femur. (b) AP radiographs three months post-operatively after correction with multiple osteotomies and stabilisation with telescopic retrograde intramedullary nail and two femoral neck screws on both sides.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5382339&req=5

Figure 6: (a) Three-dimensional reconstructions of CT scans (frontal view) of a 10.7-year-old boy (cases 12 and 13) with polyostotic fibrous dysplasia und shepherd’s crook deformation of the femur. (b) AP radiographs three months post-operatively after correction with multiple osteotomies and stabilisation with telescopic retrograde intramedullary nail and two femoral neck screws on both sides.
Mentions: Pre-operative planning was performed on orthogonal plain radiographs which produced a template that showed the degree of bony resection, correction required and likely position of the intramedullary nail. From this information, a custom-made nail was made for each case by Synthes Switzerland (Fig. 3). In surgery, the patient is placed in a supine position with slight elevation of the affected side. A direct lateral approach is made to the femur which is exposed carefully subperiosteally. A 2.5-mm Kirschner wire is introduced from the lateral cortex down the femoral neck in a central location to guide the alignment of the osteotomy. The osteotomy is made and enough bone resected to allow the deformity to be fully corrected. The distal canal is then opened with a straight reamer and if any lateral bowing is present this must be fully corrected with one or more additional osteotomies. In the growing child, a smaller male component is first placed into the medullary canal with a special T-handle. This is placed across the distal femoral physis and locked with a transverse small fragment screw (Figs 4 to 6). The female nail is then passed over the male and made flush with the cut end of the femur. For adolescents or adults, the central telescoping part is not needed. A window is made in the lateral cortex of the femur to give access to the mid part of the nail that has a series of ridges. With the deformity completely corrected, the nail can then be advanced in a retrograde fashion using a small punch inclined against the ridges. With this retrograde method, the proximal end of the nail can be inserted as medial as necessary; if it is appropriate it can even be brought to the metaphysis (Fig. 5) or even into the femoral head. Small holes in the nail at regular distances in the axis of the femoral neck screws help to maintain the orientation of the nail while hammering proximally. For the insertion of the femoral neck screws and the bolting screw in the distal epiphysis, a 3Dimage intensifier is very helpful, as the bone is very thin and axial views cannot be made before the insertion of the proximal screws, because with the leverage the nail would enlarge the hole within the soft bone. At the end of the operation, the correct rotation is secured with K-wires through the cortices of both fragments of the osteotomy.

View Article: PubMed Central - PubMed

ABSTRACT

Aims: The severe form of coxa vara, the ‘shepherd’s crook deformity’, is always a consequence of a locally extensive form of polyostotic fibrous dysplasia (or McCune-Albright syndrome). Treatment of this deformity is a challenge. The soft bone does not tolerate any implant that depends on the stability of the cortical bone (like plates or external fixators). Intramedullary nails are the most appropriate implants for stabilisation, but if they are inserted from the greater trochanter, they cannot correct the varus deformity enough.

Patients and methods: We have developed a special intramedullary nail that can be inserted from the osteotomy site and can be driven retrograde into the femoral neck in an appropriate valgus position. We have operated 15 legs in 13 patients. The average age at surgery was 14 years and 5 months (6 to 28.9). In all, 11 femora had been operated before (unsuccessfully) with various implants.

Results: The average follow-up was 54.2 months (7 to 132). The average correction of the neck/(distal) shaft angle was 57.5° (10° to 80°) ( = 72.8%). While pre-operatively none of the patients was able to walk without aid, at follow-up only one patient was unable to walk, three used the aid of crutches because of tibial lesions and one patient had an increased external rotation of the leg. At follow-up, most patients were free of pain. One implant broke and had to be replaced.

Conclusion: This new operative method offers the possibility of efficient correction and stabilisation of this severe and difficult deformation.

No MeSH data available.


Related in: MedlinePlus