Personalized alignment techniques better restore the native trochlear groove compared to systematic alignment...

Area of Science:

• Orthopaedic Surgery
• Biomechanical Engineering
• Medical Device Technology

Background:

• Restoring the native trochlear groove is crucial for optimal patellofemoral function after total knee arthroplasty (TKA).
• The influence of different constitutional coronal alignment and implant positioning strategies on trochlear groove restoration remains incompletely understood.
• Understanding these relationships is key to improving TKA outcomes and patient satisfaction.

Purpose of the Study:

• To investigate whether specific alignment philosophies significantly impact the restoration of the trochlear groove during TKA.
• To compare the effectiveness of various alignment techniques in recreating the native trochlear anatomy.
• To analyze the effect of preoperative coronal alignment on final implant positioning and trochlear restoration.

Main Methods:

• Retrospective review of 61 imageless robotic TKAs.
• Digitization of native trochlea to generate original femoral anatomy.
• Simulation of femoral component positions using mechanical alignment (MA), gap balancing (GB), kinematic alignment (KA), restricted kinematic alignment (rKA), and restricted inverse kinematic alignment (riKA) techniques.
• Comparison of trochlear angle, under/overstuffing, and mediolateral sulcus offset across techniques and with the native groove.

Main Results:

• All alignment techniques resulted in increased trochlear angle valgus compared to the native groove.
• Kinematic alignment (KA) and restricted kinematic alignment (rKA) demonstrated results closer to the native trochlear angle than GB, MA, and riKA.
• All techniques led to understuffing of the native trochlear groove, with KA and rKA showing less understuffing than other methods.
• Alignment techniques shifted the trochlear sulcus laterally in extension and medially in flexion, most notably with GB and MA.

Conclusions:

• Personalized alignment techniques, specifically KA and rKA, offer superior restoration of the native patellar groove compared to systematic alignment techniques.
• These patient-specific approaches better accommodate individual anatomical variations, leading to improved patellar groove restoration.
• The findings suggest that incorporating personalized alignment strategies is beneficial for optimizing TKA outcomes.