Femoral and Tibial Fractures in a 62-Year-Old Patient | Dr. Arash Sharafat Vaziri

A 62-year-old woman was referred to the emergency department after being injured in an accident in Jan 2021. Radiographic imaging revealed a femoral neck and proximal Tibial fractures of the right leg. In Feb 2021, during one session, she underwent hip hemiarthroplasty, and the proximal tibial fracture was fixed by a double plating technique where BMP-loaded allograft was used for bone grafting. After three months postoperatively, full weight bearing was permitted to accelerate fracture union.

Physician profile

Dr. Arash Sherafat Vaziri

Orthopedic Trauma Surgeon
Assistant Professor of Orthopedic and Trauma Surgery
Tehran University of Medical Sciences (TUMS)

Anteroposterior and lateral radiographs after fixing the proximal tibial fracture by
a double-plating technique — Anteroposterior and lateral radiographs after fixing the proximal tibial fracture by a double-plating technique

The patient was reassessed 6, 9, and 12 months after surgery. In the ninth-month follow-up evaluation, the chief complaint was debilitating right knee pain and difficulty walking. Full standing X-Ray revealed a tibial fracture nonunion and stage four osteoarthritis according to Kellgren and Lawrence classification.

Pre-operative Planning

A patient-specific porous titanium implant was used to solve the nonunion and instability challenges of TKA, which would result in fixation, augmentation, and promote osseointegration simultaneously. The porous structures promote osseointegration and biological fixation by allowing extensive body fluid diffusion through the implant pores and increasing the bone-implant contact surface. Also, the implant was designed based on the patient’s anatomy to bypass the nonunion fracture site and eliminate the mechanical instability of the fracture. The 3D model of the patient’s bone was reconstructed from the CT scan and the implant was designed based on the simulation of the TKA and the nonunion site to allow for the tibial stem to pass through it. The pore size of the porous structure was chosen to be 500 micrometers with 70% porosity to maximize osseointegration. The implant was manufactured using medical-grade titanium (Ti6Al4V) utilizing the SLM (Selective Laser Melting) technique and then sterilized.

(a) Preoperative cone design and surgical planning simulation (b) Printed customized porous titanium cone (c) Intraoperative placement of customized cone

Surgical Treatment

The treatment was performed in two stages to ensure that the nonunion is aseptic. First, levels of erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were preoperatively assessed and were found to be in the normal range, and although there were no signs of infection, device removal was done in the first stage in Jun 2022. Removal of the two screws that were embedded deep in the bone was decided to be left for the main surgery.

Postoperative AP and lateral view of first-stage device removal, showing the proximal
tibial nonunion and medial compartment osteoarthritis — Postoperative AP and lateral view of first-stage device removal, showing the proximal tibial nonunion and medial compartment osteoarthritis

Intraoperative cultures were negative after 14 days, and inflammation factors returned to the normal range after 3 weeks, therefore, the patient was a candidate for TKA with a long tibial stem to bypass the nonunion site.
In the second stage, on Sep 2022, with no sign of infection, the patient underwent primary TKA using LCCK prosthesis (NexGen, Zimmer, Warsaw, IN, USA) for arthritis by hybrid fixation (cemented metaphysis and non-cemented diaphysis). The femoral component with a 13×60 (mm) straight stem was fixed fully cemented, and the tibial component was fixed hybrid with the cementless 12×100 (mm) straight stem and customized implant to bypass the fracture site and nonunion region.

Post-operative Follow-up

The post-operative radiography showed satisfactory alignment and position of the customized implant was in agreement with the preoperative simulation. After 6 weeks, follow-up radiographic evaluations confirmed the solid union and osseointegration in progress. After 6 months, full union was observed, and the patient returned to full activity with a full knee range of motion, and no pain, instability, or stiffness existed.

AP and lateral view radiographs at 6 months, in which full bone union is observed

Physician’s Conclusion

In the presented case, due to the small distance between the nonunion site and the joint line, it was not possible to exclude the nonunion treatment due to mechanical instability for the prosthesis placement. Also, conventional techniques such as plating were inappropriate because of insufficient space.
To address the challenges, simultaneous management to the treatment of knee osteoarthritis and nonunion, using a customized 3D-printed porous titanium cone was chosen which promotes creeping substitution by providing suitable rigid fixation while bypassing the nonunion site and supporting the fixation.
One of the advantages of designing patient-specific cones using CT scan is the possibility of designing based on the exact geometry of the medullary canal, the length of the lesion, and the length required to achieve proper fixation and stability.
According to our experience in treating arthritis and aseptic nonunion by total knee arthroplasty and personalized titanium porous implant, this method may be reliable in treating cases with similar conditions.

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Femoral and Tibial Fractures in a 62-Year-Old Patient | Dr. Arash Sharafat Vaziri