Alignment strategy for different types of varus knee with generic instruments: Mechanical alignment or kinematic...

Area of Science:

• Orthopedic Surgery
• Biomechanical Engineering

Background:

• Understanding variances in total knee arthroplasty (TKA) alignment strategies is crucial for optimizing patient outcomes.
• Mechanical alignment (MA) and kinematic alignment (KA) are two distinct approaches to TKA with differing biomechanical principles.
• Varus knee deformities present unique challenges in achieving optimal TKA alignment and functional recovery.

Purpose of the Study:

• To compare the functional outcomes of mechanical alignment (MA) versus kinematic alignment (KA) in total knee arthroplasty (TKA).
• To assess perioperative and postoperative functional recovery in patients with varus knee deformity undergoing TKA.
• To evaluate patient satisfaction and pain scores using generic instruments for both alignment techniques.

Main Methods:

• A cohort of 127 patients with unilateral TKA and varus knee deformity (mCPAK types I and IV) were analyzed.
• Patients were divided into MA and KA groups, with functional outcomes assessed using KOOS JR, AROM, VAS pain, and FJS-12 Knee scores.
• Data were collected preoperatively and at 6 weeks, 6 months, and 12 months post-surgery, with complication monitoring throughout.

Main Results:

• The kinematic alignment (KA) group showed significantly reduced VAS pain scores at 6 weeks post-surgery.
• KA demonstrated significantly higher KOOS JR scores at 6 weeks, 6 months, and 12 months post-surgery.
• KA also resulted in a significant increase in FJS-12 Knee scores at 1 year post-surgery, indicating improved patient satisfaction.

Conclusions:

• Kinematic alignment (KA) offers short-term benefits in pain relief and range of motion compared to mechanical alignment (MA) in TKA.
• KA leads to enhanced patient-reported outcomes, including higher satisfaction, particularly at the one-year follow-up.
• The KA approach is a viable option for patients with mCPAK type I and IV varus knees undergoing TKA.