Surgical Treatment of Habitual Patella Dislocation with Genu Valgum

The clinical and radiological outcomes of the treatment were satisfactory. Case ReportA 23-year-old man visited our institution due to lateral dislocation of the left knee in flexion and instability that had persisted for 7 years (Fig. 1).Th e patient had a history of femoral growth plate fracture treated conservatively at 13 years of age.In the physical examination, the apprehension test was positive.In the radiographic examination, the congruence angle, sulcus angle, Q-angle, and Insall-salvati Ratio was 44.17 o , 152 o , 18 o , and 1.15, respectively.Th e tibiofemoral angle measured from the weightbearing radiograph was 16 o , indicating genu valgum deformity, and hypoplasia of the lateral femoral condyle of the left knee was observed.A skyline view of the knee showed lateral dislocation of the patella.Arthroscopic examination revealed the hypoplasia of the lateral femoral condyle, Outerbridge grade II cartilage damage on the lateral articular surface, and contracture of the lateral retinaculum and vastus lateralis.Patellar dislocation during flexion was confirmed with arthroscopy.A lateral retinacular release and an open-wedge distal fermoral varus osteotomy were followed by additional procedures including lateral release and medial reefing because dislocation was still present after the osteotomy.About 2 cm of the medial retinaculum was reefed because it was excessively elongated.When lateral dislocation of the patella in flexion was no longer observed, a bone graft was inserted into the osteotomy site.Gradual fl exion exercises were started postoperatively.Complete flexion was obtained at the Surgical Treatment of Habitual Patella Dislocation with Genu Valgum