Magnetic lengthening devices are being used more frequently and have been replacing more traditional limb lengthening techniques in recent years.1 The PRECICE nail (Nuvasive Inc.) allows for gradual lengthening through a magnetic telescopic mechanism. This allows the patient the ability to achieve a controlled lengthening along the axis of the nail from home. Due to the unknown effects of leaving this implant in place in the pediatric population, it is recommended by the Food and Drug Administration that the device be removed after 1 year.2 A unique challenge that can be encountered with this device is the dissociation of the telescoping parts of the implant when attempting hardware removal.1 There is a paucity of literature describing techniques to address this problem. Johnson et a1l described a case report in which the use of a long pituitary rongeur was successful. However, this technique requires the intramedullary canal to be large enough to accommodate this device. Another described removal technique includes performing an osteotomy to retrieve the distal portion.3 An osteotomy can be a morbid procedure to perform if the bone has already healed, and would require additional stabilization afterwards. While nail extraction hooks can be successful for cannulated nails, they do not work in nails with solid components, such as the PRECICE nail. The purpose of this article is to describe a surgical technique using an elastic intramedullary nail (EIN) to assist removal of the dissociated distal portion of a PRECICE femoral nail, to add to the surgeon’s armamentarium when troubleshooting this issue.

TECHNIQUE

A 10-year-old girl with proximal femoral focal deficiency presented 16 months after implantation of a PRECISE 2 intramedullary growing rod. She had successful lengthening with the consolidation of regeneration. The patient and her family elected for hardware removal. The patient was brought to the operating room and fluoroscopy was used to mark the interlock screws at the proximal and distal femur. The proximal interlocks were removed first. The distal interlock screws were then exposed. The distalmost screw was removed and the second distal screw was left in place to provide rotational control of the nail while attaching the nail extraction device. The proximal portion of the nail was exposed and noted to have bony overgrowth. A Steinmann pin was advanced into the proximal portion of the nail and an 11 mm reamer was used to ream the troch directly above the nail, similar to the technique described by Iobst et al.4 The nail extraction device was then screwed into the top of the nail. The remaining distal interlock screw was removed. The nail was backslapped and upon removal, only the proximal portion of the nail was noted to have been removed, indicating dissociation between the proximal and distal telescoping ends of the nail. The femur was evaluated under fluoroscopy to confirm the distal portion of the PRECICE nail remained within the intramedullary canal (Fig. 1A). A laparoscopic grasper was used to attempt to grab the top of the retained portion of the nail, whereas Steinmann pins were placed in the distal screw holes to prevent distal migration and give counter pressure, similar to the technique described by Johnson et al (Fig. 1B).1 Unfortunately, the grasper was unable to adequately grasp the nail. Next, we attempted our novel technique using a stainless steel Synthes 3.5 mm EIN. This was inserted through the distal interlock screw hole and used to push the broken nail in a retrograde manner out of the femur (Fig. 1C–E). The EIN was stout enough to push the solid nail, but also flexible enough to accommodate the bend required to enter the femur through the drill hole present from the distal interlocking screw. This was advanced until the retained nail was pushed out of the intramedullary canal and grasped with a large pickup, and the EIN was removed (Figs. 1F, 2).

FIGURE 1:

A, Broken PRECICE intramedullary nail with retention of the distal segment. B, Attempted removal with laparoscopic grasper was unsuccessful. Steinmann pins in distal interlock holes were placed to provide counter pressure for the grasper and to prevent nail migration distally. C, A 3.5 mm elastic intramedullary nail (EIN) was introduced into the distal femur using a distal interlock screw hole. D, The EIN was used to push the retained nail in a retrograde manner. E, The nail was removed from the proximal insertion site. F, Anteroposterior view of the femur showing successful removal of the PRECICE nail and EIN.

FIGURE 2:

The broken PRECICE nail after successful removal of all components.

EXPECTED OUTCOMES

At 1 month follow-up, the patient presented previously had a positive outcome. A recent clinical exam demonstrated no pain, and the patient is ambulating without any assistive devices. While additional studies with larger sample sizes are needed to further support this technique and its use within the general population, this demonstrates another option for surgeons to add to their armamentarium when they encounter retained broken intramedullary femoral nails. This technique utilizes a distal interlock hole from screw removal and does not require any additional corticotomy or osteotomy. In addition, our technique does not violate the distal femoral physis and as such prevents iatrogenic growth disturbance. This technique is a simple and effective option for retained solid femoral nails in skeletally immature patients with intramedullary canals too small for graspers and open physes that should not be instrumented with retrograde reaming or drilling.

COMPLICATIONS

There were no complications seen while using this novel technique. A theoretical complication that could occur is perforation of the proximal femur. Due to this, care should be taken while pushing the nail under fluoroscopic guidance. In addition, this technique does add to the case cost due to the cost of the EIN. Costs vary depending on institutional implant agreements.

REFERENCES 1. Johnson MA, Karkenny AJ, Arkader A, et al. Dissociation of a femoral intramedullary magnetic lengthening nail during routine hardware removal: a case report. JBJS Case Connect. 2021;11:e20.00950. doi:10.2106/JBJS.CC.20.00950 2. Health C for D and R. UPDATE: NuVasive Specialized Orthopedics’ Precice Devices - Letter to Health Care Providers. FDA. Published online June 28, 2023. Accessed November 22, 2023: https://www.fda.gov/medical-devices/letters-health-care-providers/update-nuvasive-specialized-orthopedics-precice-devices-letter-health-care-providers 3. Tiefenböck TM, Wozasek GE. Unusual complication with an intramedullary lengthening device 15 months after implantation. Injury. 2015;46:2069–2072. 4. Iobst C, Kold S, Mikuzis M. Removal of femoral lengthening nails. J Pediatr Orthop Soc N Am. 2022;4:1–18.