Tibial Deformity in a 70-Year-Old Patient | Dr. Arash Sharafat Vaziri

he patient was a 70-year-old woman with a 20-year history of bilateral mechanical knee pain and progressive instability. She had a neglected dislocation of the left knee and a history of left tibial surgery 25 years earlier, although detailed records were unavailable. Seven years before presentation, she underwent revision TKA on the right side for aseptic loosening but declined left-side surgery, leading to further deterioration. On examination, she exhibited severe anterior bowing of the left tibia, a 6-cm limb length discrepancy, and global knee instability with a range of motion from –40° to 120°. The knee relocated only in flexion, indicating severely damaged soft tissues. Radiological studies revealed bifocal tibial deformities in the sagittal plane, with CORAs at the proximal tibial head (45°) and proximal shaft (24°), totaling almost 70° of sagittal malalignment. CT-based 3D reconstruction confirmed the complexity of the deformities and the need for individualized correction. The patient consented to undergo surgery and for her clinical data to be published.

Physician profile

Dr. Arash Sherafat Vaziri

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

Clinical images captured before the surgery demonstrating the left knee’s recurvatum
deformity and the left tibia’s anterior bowing with unequal leg lengths. — Clinical images captured before the surgery demonstrating the left knee’s recurvatum deformity and the left tibia’s anterior bowing with unequal leg lengths.

Preoperative anterior-posterior full-leg view of a weight-bearing x-ray with mechanical angles and lateral view x-rays in flexion and extension of the knee. The knee is relocated when flexed.

Pre-operative Planning

Given the combination of severe osteoarthritis, global ligamentous insufficiency, and high-degree sagittal deformity, standard instrumentation was unsuitable. A CT scan of both lower limbs was obtained (0.5-mm slices), and advanced 3D modeling software was used to reconstruct the tibia and identify optimal correction strategies. Virtual simulation demonstrated that an anterior closed wedge osteotomy combined with a rotating hinge knee (RHK) prosthesis would best restore mechanical alignment. In collaboration with a local engineering team, two sets of patient-specific cutting guides one for the proximal tibial resection and one for the shaft osteotomy were designed and produced using selective laser sintering of polyamide powder. A full-size 3D model of the tibia allowed surgeons to rehearse the cuts before surgery, ensuring accuracy and minimizing intraoperative uncertainty.

Preoperative x-ray in manual limb traction
showing the relocated knee joint. — Preoperative x-ray in manual limb traction showing the relocated knee joint.

Preoperative 3D virtualization of the left tibia and its deformity measure

Surgical Treatment

Under general anesthesia, the procedure began with positioning the tibial shaft osteotomy guide, which featured a unique anterior “antenna” designed to align precisely with the anterior edge of the tibial plateau. After pinning the guide, the antenna was removed and replaced with the proximal tibial PSG to verify the accuracy of pin placement before transitioning to conventional Zimmer cutting blocks. Following preparation of the tibial plateau and femoral cuts, a transverse fibular osteotomy was performed through a lateral approach, and an anterior closing wedge osteotomy of the tibia was completed. Correction of the distal CORA realigned the medullary canal, allowing insertion of a cementless stem (75 × 10 mm) through the narrow tibial isthmus (10.5 mm). A hybrid fixation technique was employed, with cementation of the proximal tibial metaphysis and an uncemented cone and stem to bypass the osteotomy site. Plate fixation reinforced rotational stability. Conventional fluoroscopy was not required because the PSGs provided exact guidance for the osteotomy planes. Immediate postoperative radiographs showed neutral limb alignment and optimal component positioning.

Proximal tibial cutting guide. 3D planned virtualization and 3D-printed actual guide on the bone model

Tibial shaft osteotomy cutting guide and bone model. 3D planned virtualization and 3D-printed actual guide on the printed model of the left tibia

Intraoperative photograph demonstrating the application of the 3D-printed
osteotomy guide with its antenna resting at the anterior edge of the tibial
plateau and fixated by pins at the osteotomy site — Intraoperative photograph demonstrating the application of the 3D-printed osteotomy guide with its antenna resting at the anterior edge of the tibial plateau and fixated by pins at the osteotomy site

Intraoperative image after plate fixation of the tibial osteotomy site

Post-operative Follow-up

Serial radiographs at 3, 6, and 12 months demonstrated progressive bone healing, culminating in complete union of the osteotomy site at one year. Clinically, the patient achieved independent ambulation, correction of limb alignment, and resolution of instability. Follow-up images confirmed stable prosthesis fixation with appropriate sagittal and coronal alignment. No postoperative complications were encountered. The patient’s improved gait and functional capacity were documented in follow-up video recordings.

X-rays obtained 12 months after surgery in the anterior-posterior (left) and lateral (right) views show the knee prosthesis in position. The arrow on the right
image points to the bony union at the osteotomy site — X-rays obtained 12 months after surgery in the anterior-posterior (left) and lateral (right) views show the knee prosthesis in position. The arrow on the right image points to the bony union at the osteotomy site

Clinical images obtained 3 months after surgery revealing the correction of left lower limb malalignment.

Physician’s Conclusion

This case highlights the value of patient-specific instrumentation for the management of complex extra-articular tibial deformities requiring concurrent TKA. The combination of meticulous virtual planning, surgeon–engineer collaboration, and carefully designed PSGs enabled accurate deformity correction, minimized soft-tissue injury, and ensured ideal implant positioning. Although PSI has shown variable benefit in routine arthroplasty, this case demonstrates its powerful role in challenging anatomy where standard guides are unreliable. The successful outcome underscores the importance of individualized preoperative planning and the expertise of experienced knee surgeons when addressing severe deformities. Broader clinical studies are needed to further define the indications and long-term effectiveness of PSI in such demanding surgical scenarios.

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Tibial Deformity in a 70-Year-Old Patient | Dr. Arash Sharafat Vaziri