Total Knee Arthroplasty for Fixed Valgus Deformity Correction Using a Modified Lateral Parapatellar Approach

Area of Science:

• Orthopedic Surgery
• Arthroplasty
• Biomechanics

Background:

• Total knee arthroplasty (TKA) for severe valgus deformity (>10 degrees) presents surgical challenges, often leading to variable outcomes.
• The lateral parapatellar approach (LPA) offers potential benefits over traditional medial approaches for valgus knees, including improved ligamentous release and patellar tracking.

Purpose of the Study:

• To evaluate the efficacy and reproducibility of a modified lateral parapatellar approach (LPA) with Z-capsuloplasty for total knee arthroplasty (TKA) in patients with severe valgus deformity.
• To assess radiographic alignment, clinical outcomes, range of motion, and complication rates associated with this surgical technique.

Main Methods:

• A case series of 35 primary TKAs in 30 patients with osteoarthritis and severe valgus deformity (Ranawat type-II) using a modified LPA with Z-capsuloplasty.
• Patients were evaluated pre- and postoperatively for coronal alignment (femorotibial angle), range of motion (ROM), Knee Society Score (KSS), and complications.

Main Results:

• Mean coronal alignment improved from 20.4 degrees valgus to 7.0 degrees valgus postoperatively.
• Knee Society Scores significantly improved, with objective and functional scores averaging 91.8 and 84.3, respectively.
• Mean ROM increased from 94.9 to 105.7 degrees, with a 8.6% complication rate (nerve palsy, hematoma, infection).

Conclusions:

• The modified lateral parapatellar approach (LPA) with Z-capsuloplasty is a reproducible and effective surgical technique for TKA in patients with severe valgus deformity.
• This approach facilitates deformity correction and improves functional outcomes while maintaining a manageable complication profile.