A case series of total knee arthroplasty with a non-constrained implant in 2nd and 3rd degree valgus deformity in knee osteoarthritis and medial collateral ligament insufficiency

INTRODUCTION: Osteoarthritis is one of the leading causes of disability and the most common degenerative disease of the knee that causes enormous pain. As many as 10–15 % of patients requiring total knee arthroplasty (TKA) present with valgus knee deformity. When fully constrained TKA is not possible, the surgeon must use a different method to achieve a good result. CASE DESCRIPTION: A 56-year-old female with 3rd degree (48-degree) and a 62-year-old male with 2nd degree valgus knee (13-degree) with painful osteoarthritis were examined. Both have valgus thrust gait and medial collateral ligament (MCL) laxity and underwent TKA using non-constrained implants. During surgical exposure, MCL insufficiency was found in both patients, and MCL augmentation was performed. Post-operative assessment and 4-month follow-up were done through clinical and radiological parameters using the knee scoring system. DISCUSSION: A good outcome could still be achieved with a primary TKA implant in severe and moderate valgus knees with MCL insufficiency using MCL augmentation. The primary TKA implant proved to improve clinical and radiological parameters after 4 months of follow-up. Clinically, both patients no longer felt pain in their knees and were able to walk with better stability. Radiologically, there was a much-reduced valgus degree. The results were the first case went from 48-degree to 2-degree and the second case went from 13-degree to 6-degree. CONCLUSION: Knee osteoarthritis with valgus deformity and MCL insufficiency present surgical challenges during TKA. It is still possible to use in severe or moderate valgus with MCL insufficiency, which was proven by satisfactory clinical and radiological findings. Although a non-constrained option is not ideal, it is still the first choice in certain cases.