|Year : 2021 | Volume
| Issue : 2 | Page : 139-141
Bifocal femoral lengthening with intramedullary magnetic lengthening nail following osteotomy propagation
Jordan Taylor Carter1, Madison Craft2, Sherif Dabash3, Ahmed M Thabet4, Amr Abdelgawad5
1 Department of Orthopedics Surgery, University of Texas Health Science Center San Antonio, San Antonio, USA
2 Department of Orthopedic Surgery, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
3 Advanced Orthopaedics and Sports Medicine, Houston, Texas; Department of Orthopedic Surgery, Ain Shams University Hospital, Cairo, Egypt
4 Department of Orthopedic Surgery and Rehabilitation, Texas Tech University Health Sciences Center El Paso, Paul L Foster School of Medicine, El Paso, Texas, USA
5 Department of Orthopedic Surgery, Maimonides Medical Center, Brooklyn, New York, USA
|Date of Submission||08-Mar-2021|
|Date of Decision||06-Jul-2021|
|Date of Acceptance||25-Aug-2021|
|Date of Web Publication||30-Dec-2021|
Dr. Ahmed M Thabet
5001 El Paso Dr, El Paso, Texas
Source of Support: None, Conflict of Interest: None
Techniques in limb lengthening have evolved since the early 1900s. The external fixation using an Ilizarov frame was the current gold standard. Recently, intramedullary devices have been utilized in limb lengthening procedures to avoid complications related to the bulky external fixators. Here, we present the case of a 41-year-old female with long-term limb length discrepancy (LLD) corrected with magnetically driven intramedullary nailing. An intraoperative fracture of the distal femur led to bifocal lengthening at both the osteotomy site and the fracture site. This case cautioned the orthopedic surgeons involved in limb lengthening surgery about potential complications that can happen during the procedure. It demonstrated the possible efficacy of bifocal lengthening procedures using a magnetically driven intramedullary nail in the setting of complex LLD.
Keywords: Bifocal limb lengthening, femoral lengthening, PRECICE, telescopic magnetic lengthening nail
|How to cite this article:|
Carter JT, Craft M, Dabash S, Thabet AM, Abdelgawad A. Bifocal femoral lengthening with intramedullary magnetic lengthening nail following osteotomy propagation. J Limb Lengthen Reconstr 2021;7:139-41
|How to cite this URL:|
Carter JT, Craft M, Dabash S, Thabet AM, Abdelgawad A. Bifocal femoral lengthening with intramedullary magnetic lengthening nail following osteotomy propagation. J Limb Lengthen Reconstr [serial online] 2021 [cited 2022 May 24];7:139-41. Available from: https://www.jlimblengthrecon.org/text.asp?2021/7/2/139/334383
| Introduction|| |
Techniques in limb lengthening have continued to evolve since their inception in the early 1900s. Traditionally, the Ilizarov method has been the gold standard for limb lengthening procedures and works through distraction osteogenesis to promote new bone growth with an external fixator., However, several complications have been reported directly related to the external device.,,
Recently, the concept of distraction osteogenesis has been applied to intramedullary devices, including the PRECICE nail (NuVasive, San Diego, CA, USA). This device uses a magnetically driven motor to expand the nail. With nail expansion, done distraction will occur at the level of the osteotomy which will result in distaction osteogenesis and new bone formation at the level of the bone osteotmy.,,
This case report describes a case of limb length discrepancy (LLD) correction with a PRECICE nail resulting in unplanned bifocal femoral lengthening.
| Case Report|| |
A 41-year-old Hispanic female presented to our clinic with limping and left LLD affecting her daily life for many years. Her past medical history was significant for osteomyelitis of the left femur when she was 8 years old requiring multiple surgeries and eventually left knee fusion. The patient was free of any signs of infection for the last 32 years. Physical examination of the left lower extremity was significant for downward pelvic tilt, and the knee was fused in extension. Imaging confirmed an 8-cm leg length discrepancy in the left femur as compared to the right [Figure 1]. After discussion of management options, she agreed to an elective left femur lengthening osteoplasty with a PRECICE magnetic intramedullary nail. The patient had no clinical signs of infection that can be considered as a contraindication for femoral lengthening with internal fixation.
The patient was positioned supine on a flattop, prepped, and draped in sterile fashion. A 3-cm incision centered over the greater trochanter was made, and the entry point was identified using fluoroscopy and a ball-tipped guidewire. Sclerotic tissue in the proximal shaft of the femur prevented the advancement of the guidewire. A hand reamer was used to pass through this area. Multiple drill holes at the site of planned osteotomy were then performed. Additional venting holes were added in the distal femur to reduce the likelihood of fat embolism. Standard reaming was performed in 0.5-mm increments to reach 12.5 mm, 2 mm larger than the nail diameter. During passage of the nail, there was lateral propagation of a previously unnoticed fracture in the distal femur deemed to be a result of the venting hole that was placed in the distal femur. The fracture was fixed using a 4.5-mm dynamic compression plate with three unicortical locking screws proximally around the nail along with two bicortical screws and one unicortical screw distally. The PRECICE nail was then secured with two proximal locking screws and three distal locking screws. After burying the nail 2 cm into the proximal femur [Figure 2] and checking for alignment and fixation, intraoperative distraction of 1 mm as recommended by the manufacturer was applied to ensure the integrity of the lengthening mechanism of the nail.
The patient was instructed to be nonweight-bearing. Distraction was initiated on postoperative day 10 at a rate of 1 mm/day in 0.25-mm increments. One week after starting the distraction, plain radiographs showed distraction occurring at both the osteotomy site and the fracture site with displacement of the distal plate. After discussion with the patient, the decision was made to continue lengthening with close follow-up. The weight-bearing status now progressed to toe-touch weight-bearing. On postoperative week 13, the patient was progressed to weight-bearing as tolerated. By the end of the lengthening schedule, the patient had 5 cm lengthening: 2.5-cm distraction at the osteotomy site and 2.5-cm distraction at the fracture site. The LLD was not fully corrected as she would not be able to clear her knee due to her ipsilateral knee arthrodesis. At 9 months postoperatively, proper alignment of the distal femur was maintained during lengthening, and no backing out of the distal locking screws was found and the patient was allowed to fully weight bear [Figure 3].
|Figure 3: Nine-month postoperative X-rays demonstrating bifocal lengthening sites|
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At 15 months postoperatively, she had developed delayed union of the femoral osteotomy site and continual anterior thigh pain. She continued to have pain at the fracture site in subsequent visits. The patient denied any further surgeries, however, with continued pain, an operative intervention approximately 4 years after the initial limb lengthening procedure was performed to remove the plate and screws previously placed. A new plate was used to achieve femur consolidation along with cerclage wires at the level of the previously planned osteotomy. Autologous bone grafting was utilized to correct the 2-cm nonunion gap [Figure 4]. At the last follow-up, she noted significant functional improvement.
|Figure 4: Three-month postoperative X-rays after removal of previous distal femoral plate and fixation with a new plate and cerclage wires to correct nonunion|
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| Discussion|| |
Motorized, internal lengthening devices have eliminated many of the complications previously encountered in LLD correction related to external fixators such as pin-site infections, transfixation of soft tissues, pain, and immobility related to the weight of the device., These devices effectively maintain anatomic alignment during the lengthening and consolidation phase of LLD correction while improving the psychological well-being of the patients by eliminating the large external frame and pin-site scars.
Magnetic lengthening nails are solid, straight nails that may not match the anterior bow of the femur and require reaming to a diameter 2 mm larger than the nail. Venting of the medullary canal before reaming of the canal is essential to avoid fat embolisms. However, this increases the risk of fracture propagation, as seen in the case above. This unanticipated fracture was likely due to the patient's severe osteoporosis but does represent a potential danger in these patients.
However, this unanticipated event created a second lengthening site that ultimately decreased the time needed to achieve the distraction goal without sacrificing the functional integrity to the patient's osteoporotic femur. Previous studies have demonstrated the effectiveness of bifocal lengthening procedures, particularly in cases of severe LLD or highly complex deformities. Previous studies report an optimal lengthening rate of 1 mm/day, though this is highly patient specific. Our patient's LLD was corrected at a rate of 1 mm/day in 0.25-mm increments four times per day; the rate was later reduced to 0.5 mm to accommodate the poor regenerate at the planned osteotomy site. This rate was found to minimize patient discomfort and allowed for correction of LLD in 9 months.
Malunion and nonunion are well-known complications of limb lengthening procedures. Traditional management of these complications includes halting the lengthening, injection of bone marrow aspirate, open autologous bone grafting, exchange nailing, or use of a plate to attempt femoral consolidation. The above case was complicated by nonunion of the osteotomy site, successfully treated with plating, cerclage wires, and autologous bone grafting.
This case shows the possibility of bifocal lengthening using a motorized intramedullary nail lengthener. There were lessons learned from mistakes in this case. One mistake was performing a separate distal venting hole in the femur. The drill holes of the multiple drill holes osteotomy can function as venting holes which will allow using the reaming material as a bone graft for the future regenerate. This bone grafting could have resulted in better regenerate for outpatient and possible avoiding of the regenerate nonunion. Despite these mistakes, the case still shows that bifocal femoral lengthening can be done with magnetic intramedullary lengthening nail. This is the first description of bifocal lengthening using the magnetic intramedullary nail.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient (s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]