Valgus instability can occur after total knee arthroplasty (TKA) due to traumatic medial collateral ligament (MCL) injury, component malpositioning, or progressive ligamentous laxity. Although revision TKA with exchange of the polyethylene to a varus-valgus-constrained liner can reduce laxity due to MCL insufficiency, isolated liner exchange in the setting of collateral ligament insufficiency may lead to greater strain at the cement-bone or implant-cement interface and possibly a greater rate of aseptic loosening. Anatomic MCL reconstruction can be performed in conjunction with liner exchange to restore stability and reduce strain compared with liner exchange alone. The purpose of this Technical Note is to describe a technique for MCL reconstruction and liner exchange for treatment of valgus instability after TKA., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: A.C.K. reports Editorial Board member for Arthroscopy. A.F.V. reports a relationship with American Academy of Orthopaedic Surgeons that includes: board membership; a relationship with American Orthopaedic Society for Sports Medicine that includes: board membership; a relationship with Arthrex that includes: funding grants; and a relationship with 10.13039/100008894Stryker that includes: consulting or advisory. J.C.R. reports a relationship with American Academy of Orthopaedic Surgeons that includes: board membership; a relationship with Aerobiotix that includes: consulting or advisory; a relationship with DePuy Orthopaedics that includes: consulting or advisory; and a relationship with Zimmer that includes: consulting or advisory. M.T.P. reports a relationship with 10.13039/100009885American Academy of Orthopaedic Surgeons that includes: board membership; a relationship with 10.13039/100011549American Orthopaedic Society for Sports Medicine that includes: board membership; a relationship with 10.13039/100013615American Shoulder and Elbow Surgeons that includes: board membership; a relationship with 10.13039/100007307Arthrex that includes: consulting or advisory and funding grants; a relationship with 10.13039/100008542Arthroscopy Association of North America that includes: board membership; a relationship with Elsevier that includes: consulting or advisory and funding grants; a relationship with International Society of Arthroscopy Knee Surgery and Orthopaedic Sports Medicine that includes: board membership; a relationship with JRF Ortho that includes: consulting or advisory; a relationship with Knee that includes: board membership; a relationship with Orthopedics that includes: board membership; a relationship with San Diego Shoulder Institute that includes: board membership; a relationship with Slack Incorporated that includes: board membership, consulting or advisory, and funding grants; and a relationship with The Society of Military Orthopaedic Surgeons that includes: board membership. R.H.K. reports a relationship with DJO Global that includes: consulting or advisory; a relationship with Innomed that includes: consulting or advisory; and a relationship with International Orthopedic Education Network that includes: board membership. T.R.H. reports a relationship with Arthrex that includes: consulting or advisory and funding grants; and a relationship with NICE Recovery Solutions that includes: equity or stocks. All other authors (C.C.L., R.J.W.) declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)