Background: Increased posterior tibial slope (PTS) is considered a risk factor for anterior cruciate ligament (ACL) injury. Previous studies revealed that medial opening wedge high tibial osteotomy (OWHTO) tends to increase PTS. However, knee instability from increased PTS is not a reported complication after OWHTO, and the treatment strategy is unclear.
Methods: A 55-year-old woman who complained of left knee pain underwent OWHTO for early-stage medial compartment osteoarthritis by another doctor. After the first surgery, her left knee pain decreased; however, 1 year after OWHTO, she began to feel left knee instability, and the primary doctor consulted our clinic. Physical examination revealed a positive Lachman's test, and radiographs showed that PTS had increased from 8 degrees to 15 degrees. According to these findings, we diagnosed an aggravated symptomatic knee instability secondary to increased PTS after OWHTO. We then performed ACL reconstruction using the quadriceps tendon and tibial anterior closing wedge osteotomy (ACWO), which is a newly-developed technique to correct PTS for revision ACL reconstruction.
Results: Postoperatively, PTS was corrected from 15 degrees to 7 degrees, and the patient's Lysholm score improved from 39 to 95, 1 year postoperatively.
Conclusions: ACL reconstruction with ACWO is a possible treatment option for the PTS-increased knee after OWHTO.
Keywords: Anterior closing wedge osteotomy; Anterior cruciate ligament; Opening wedge high tibial osteotomy; Posterior tibial slope.
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