Hipoplasia/agenesia patelar bilateral, gonartrosis avanzada y deformidad en ráfaga de viento tratadas mediante artroplastía total de rodilla asistida con robot

Abstract

Introduction:
Windswept deformity of the knee is characterized by the simultaneous presence of varus deformity in one limb and valgus deformity in the contralateral limb. It is an uncommon presentation of advanced bilateral osteoarthritis and represents a technical challenge for total knee arthroplasty due to the coexistence of bone defects, soft-tissue contractures, ligamentous laxity, and different soft-tissue balancing requirements in each knee. Patellar hypoplasia or agenesis adds further complexity, as it alters the anatomy of the extensor mechanism, trochlear morphology, and patellofemoral kinematics.

Objective:
To describe the case of a 57-year-old male patient with bilateral patellar hypoplasia/agenesis, advanced bilateral knee osteoarthritis, and windswept deformity, treated with CORI robotic-assisted total knee arthroplasty, and to discuss the relevant clinical and surgical considerations for its presentation as a case report.

Case Presentation:
A 57-year-old male patient presented with progressive bilateral knee pain of approximately three years’ duration, predominantly on the right side, associated with altered limb alignment, a sensation of instability, and plantigrade gait assisted with a cane. Physical examination of the right knee showed 110° of flexion, a 5° extension deficit, and a positive lateral opening stress test. Subsequent evaluation of the contralateral knee documented 95° of flexion, a 5° extension deficit, a positive lateral opening stress test, and an 18° reducible valgus deformity. The comprehensive diagnosis was bilateral patellar hypoplasia/agenesis, advanced bilateral knee osteoarthritis, and windswept deformity.

Intervention:
A right robotic-assisted total knee arthroplasty using the CORI system was performed on December 8, 2025, without the use of a tourniquet and with an estimated blood loss of 100 mL. Subsequently, contralateral robotic-assisted total knee arthroplasty was performed on April 15, 2026, with an estimated blood loss of 100 mL. In the source material, the second surgery is recorded as “right”; however, based on the clinical sequence and the documented examination of the left knee, laterality should be verified before editorial submission.

Conclusion:
This case is relevant due to the rare association of bilateral patellar hypoplasia/agenesis with severe knee osteoarthritis and windswept deformity. Individualized planning, ligamentous balancing, and robotic assistance may be useful for reproducing bone cuts, controlling limb alignment, and adapting the surgical strategy to opposing deformities in each knee.