Medial Joint Opening in the Operated Knee After Unilateral High Tibial Osteotomy: Risk of Osteoarthritis and Future Surgery in the Operated and Nonoperated Knee

A large medial joint opening (a small postoperative JLCA) in the operated knee after unilateral HTO was associated with a higher risk of OA progression and surgery in the nonoperated knee. Conversely, a small medial joint opening (a large postoperative JLCA) was associated with a higher risk of OA progression and conversion to arthroplasty in the operated knee. For a balanced medial joint opening, if the postoperative JLCA was between 1.5° and 3.9° or the ΔJLCA was between -5.6° and -1.7°, a favorable prognosis in both knees could be anticipated.