A combination of osteotomy and ligament reconstruction is recommended for posterolateral rotatory instability (PLRI) with large cubitus varus deformities. There is a lack of reports regarding ligament donor selection for ligament reconstruction of PLRI with cubitus varus. Two cases of PLRI with cubitus varus have been described. In case one, a 40-year-old woman presented with left elbow pain. She had a cubitus varus deformity, resulting from a childhood elbow fracture. Radiographs showed an 18-degree cubitus varus deformity. A lateral closing wedge osteotomy and double plate osteosynthesis were performed. The lateral collateral ligament (LCL) was reconstructed with autologous triceps fascia. Postoperative radiographs confirmed correction with 10 degrees of the carrying angle (CA). Bone union at the osteotomy site occurred six months later with excellent results. In case two, a 45-year-old man presented an arm with persistent right elbow instability with cubitus varus deformity. This was due to a childhood supracondylar fracture of the right humerus. Radiographs showed a cubitus varus deformity of 25 degrees on the right. The surgical procedure included a lateral wedge osteotomy, double plate fixation, and LCL reconstruction with autologous triceps fascia. Postoperative radiographs confirmed a corrected CA of 5 degrees. Bone union was achieved at the six-month follow-up with satisfactory results. The use of triceps fascia for LCL reconstruction for PLRI due to cubitus varus would provide a minimally invasive and reasonable treatment option.