A 90-year-old woman presented to the ED after sustaining a ground-level fall onto her right knee earlier in the day.
Her medical history is significant for atrial fibrillation on apixaban, peripheral arterial disease, aortic valve stenosis and chronic kidney disease. On presentation, she was found to have a displaced right interprosthetic femur fracture for which orthopedics was consulted for management.
Her initial evaluation involved orthogonal radiographs of the affected limb demonstrating a displaced and shortened spiral femur fracture without obvious involvement of the total hip or knee arthroplasties (Figure 1). Clinically, there was significant swelling and ecchymosis but no open wounds around the knee or thigh. The patient remained neurovascularly intact without compromise. A CT scan was obtained to ensure there was no proximal or distal propagation of the fracture. Per the patient, she had her THA and TKA procedures performed about 15 years ago and had been functioning well. Given her multiple medical comorbidities, the medicine team was consulted for medical optimization and risk stratification, finding her to be high risk for perioperative morbidity and mortality, but overall optimized.
The potential for significant osteoporosis and poor bone quality, length of fracture propagation and the need to provide a stable construct that would allow immediate weight-bearing needed to be considered.
We elected to proceed with a proximal femur hook plate with a distal extension and the percutaneous photodynamic bone stabilization system (IlluminOss) intramedullary (IM) device.
The patient was brought to the OR for surgery the next day after her presentation. She was positioned supine with a foam ramp under the surgical leg to assist with imaging and reduction. A direct lateral incision centered over the fracture and extended distally to the supracondylar femur region was made with an iliotibial band split and subvastus approach to directly reduce the spiral fracture with a clamp. Once length, alignment and rotation were confirmed, we proceeded with placing the photodynamic bone stabilization system device in a retrograde fashion from the lateral femoral condyle. A starting awl was placed in the center of the distal femur on lateral radiographs and as distal as possible on the anteroposterior (AP) radiographs in relation to the TKA to capture as much distal bone as possible (Figure 2). The awl was inserted with an oblique trajectory aimed proximally. Once inserted, a guidewire was introduced through the awl, past the fracture, to the level of the distal THA stem to secure the position and facilitate reaming. We reamed the IM canal up to the appropriate size. The desired implant length was determined and the implant was inserted over the cannula with a Seldinger-like technique. The device was placed under fluoroscopy, confirmed to be in good position both proximally and distally and filled with polymer until we could visually detect the device filling as much of the canal as possible (Figure 3). We proceeded with ultraviolet light-curing of the polymer. Once the polymer cured, we proceeded with application of the proximal femur hook plate via a direct lateral incision over the greater trochanter. Once the proximal aspect of the plate was secured, we turned to the distal femur extension component. Via the previous lateral incision, the proximal femur hook plate and the distal femur extension plate were connected. Once this was secure distally and the overall plate construct position was confirmed on orthogonal imaging, the remainder of the screws were placed through the plate intending to penetrate the IM bone stabilization implant to increase screw purchase and fixation (Figure 4).
The incisions were irrigated, closed and the patient was awakened without any issues. She was made weight-bearing as tolerated to the operative extremity with unrestricted range of motion with follow-up at 3 weeks, 6 weeks and 3 months. She was seen at 3-month follow-up and was without pain. She has returned to ambulation with therapy. Radiographs demonstrate good healing without loss of reduction or hardware failure.
Periprosthetic femur fractures are common injury patterns seen in the older population and are attributed to progressive osteoporosis and increasing incidence of arthroplasty. In the setting of well-fixed implants and enough bone stock for open reduction and internal fixation (ORIF), these fractures are amenable to operative fixation. The challenge remains in providing adequate fixation around the fracture while spanning the femur for protection and securing the fixation around the arthroplasty components. Ideally, immediate weight-bearing and mobilization in this population is preferrable to help prevent medical complications. While there are well recognized implants for proximal or distal periprosthetic femur fractures, interprosthetic injury patterns are less commonly encountered despite the increase in incidence.
Implant innovation has provided orthopedic surgeons with proximal femur and distal femur locking plates to secure length-stable fixation particularly in osteoporotic bone. Newer proximal femur prosthetic plates have the added addition of a greater trochanter hook that can help with compression and stabilization, as well as variable-angle locking screws for peri-implant fixation flexibility. Distally, the distal femur locking plates have also improved in a similar manner allowing for optimal distal fixation and long plate lengths to span the femur. Unfortunately, many of these options either cover the proximal or distal aspect of the bone while leaving the opposite end without optimal fixation options, particularly in patients who have ipsilateral THA and TKA. With this issue in mind, implant companies have designed extension augmentation plates that may be added to the locking plates to span the entire femur and improve distal or proximal fixation. Therefore, in this case, the decision was made to use a proximal femur locking hook plate with distal femur spanning attachment to span the entire femur about the well-fixed arthroplasty implants.
One limitation of lateral femur plates used in isolation is the concern to progress weight-bearing without threatening hardware failure. In recent years, dual implant implementation has become popularized, particularly in the older population, to facilitate early mobilization. Particularly in distal femur fractures, dual-plate or plate-nail constructs have shown the ability to support early weight-bearing without risk of hardware failure. The advent of IM photodynamic bone stabilization implants has created another potential implant option for expedient implementation via a minimally invasive approach, which provides relative stability to metaphyseal and diaphyseal injuries like an IM nail provides. Unlike a nail, the IM photodynamic bone stabilization implant has the added benefit of allowing the surgeon to drill into the implant and potentially increase the strength of the screws and bone purchase in osteoporotic bone, as well as combine the different implants. In combination with other well-known implants, like lateral femur locking plates, these constructs may provide another option for fixation in these difficult fractures through the benefit of an IM device, which supplements bone stock for plate fixation, particularly in this older population. In addition, the device can be placed percutaneously and the presence or absence of an open-box TKA does not factor into decision-making. With the additional support of the photodynamic implant with the plate, early weight-bearing can be allowed, to help support patient recovery.
The photodynamic implant was initially used mostly in the oncology setting for impending pathologic fractures of the humerus, distal radius and pelvis. It is a polymer-filled IM balloon that, when cured with ultraviolet light, creates a hard, stabilizing construct with bony interdigitation that facilitates bony healing and pain control. With the advent of longer and wider implants, the application has broadened to other situations in which IM implementation may be helpful. The main benefit of these devices is these can be placed percutaneously under fluoroscopy with interdigitation into the medullary canal decreasing the surgical burden previously created by ORIF. Concerns for using the photodynamic bone system is the amount of heat generated when curing with UV light and removal of the implant, if needed. While no issues have been reported with bone healing, the brief high temperatures remain a concern. Further, if device removal is necessary for infection, future surgery or periprosthetic fracture or hardware failure, the interdigitation and lack of removal equipment are potentially problematic. While there have not been reports of implant removal that we are aware of within the literature, this is certainly an area of concern that requires more investigation.
Interprosthetic femur fractures in the older, osteoporotic patient represent a unique challenge, particularly when there is significant risk for perioperative morbidity. While proximal or distal femur lateral locking plates have improved fixation in osteoporotic complex fractures, alone these may not have enough fixation to prevent nonunion/malunion or implant failure with the goal of early weight-bearing and mobilization. Combining these plates with proximal or distal extensions and a second implant can facilitate protecting the entire length of the femur while allowing for early range of motion and mobilization. In this case, combining new lateral locking plate technology with the expedient and minimally invasive nature of an IM photodynamic bone stabilization device provided another option in the care of a medically and technically complex patient.
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