A double-level osteotomy involves a high tibial osteotomy and a distal femoral osteotomy in the same procedure in patients who have marked alignment problems.
Double-level osteotomy for large or complex corrections
Adequate digital planning on long leg weight-bearing X-rays will usually guide the surgeon as to the amount of correction that can be safely provided by correction in one bone. If safety is likely to be compromised, then planning can point to corrections in both upper and lower limb simultaneously to provide adequate safe realignment.
Double level osteotomy of the knee: a method to retain joint-line obliquity. Clinical results. Babis GC, An KN, Chao EY, Rand JA, Sim FH. J Bone Joint Surg Am. 2002 Aug;84-A(8):1380-8.