Distal femoral osteotomies improves recurrent patellar instability in patients with genu valgum: A systematic review

IMPORTANCE: Coronal plane malalignment can contribute to recurrent patellar instability, a common knee pathology, particularly in adolescents that can negatively impact knee function and stability. OBJECTIVE: To systematically review the literature in order to summarize the clinical and radiologic outcomes of the surgical treatment of recurrent lateral patellar instability in patients with genu valgum using varus-producing distal femoral osteotomies (DFOs). EVIDENCE REVIEW: A systematic review was conducted using PubMed, Cochrane Library, and OVID Medline databases from 1990 to present. Inclusion criteria were: outcomes of lateral opening- and medial closing-DFOs performed for treatment of recurrent patellar instability with associated genu valgum, minimum 90-day follow-up, English language articles, and human studies. Data extracted included demographic information, type of osteotomy and concomitant procedures, radiological outcomes, patient reported outcome scores, and incidence of complications. FINDINGS: Nine studies, with a total of 147 knees were available for review. All included studies were retrospective case series, with a weighted mean follow-up of 2.75 ​± ​0.75 years. 6 of 147 (4.08%) knees demonstrated recurrent patellar instability. All studies reported good to excellent patient-reported outcomes postoperatively, with improvement from pre-operative measures. All studies reported relative normalization of measurements of mechanical axis and/or lateral distal femoral angle (LDFA) postoperatively. 63 of 147 (42.86%) knees underwent re-operation, with hardware removal [53 of 147 (36.05%) knees] being the most commonly performed procedure. CONCLUSIONS: Varus-producing DFOs are an efficacious procedure to improve functionality and radiographic malalignment and address recurrent patellar instability in patients with associated valgus deformity. Additional higher-level of evidence studies utilizing matched control groups, such as patients undergoing conservative treatment, with standardized reporting of outcomes should be performed in order to better understand clinical and radiographic outcomes of varus-producing DFOs for this indication. STUDY DESIGN: Systematic review.