Minimally invasive medial patellofemoral ligament reconstruction for patellar instability using an artificial ligament: A two year follow-up

Introduction: Recurrence of acute patellar dislocation affects approximately 30% of individuals, and up to 75% of those with grade IV instability. The medial patellofemoral ligament (MPFL) is considered to be critical for patella stabilisation. MPFL reconstruction with allografts has been proposed to reduce risk of recurrence, but there is limited evidence about the safety and effectiveness of techniques using synthetic allografts. Method: We present a retrospective case series of 29 individuals who underwent a MPFL reconstruction between 2009 and 2012, using an artificial ligament for patellar instability by a single surgeon. Clinical, radiological and functional outcomes were measured at a minimum of 24 months. Results: 31 knees (29 individuals) were followed up for a median of 43 (range: 24 – 68) months. Using the Crosby and Insall grading system, 21 (68%) were graded as excellent, 9 (29%) were good, 1 (3%) as fair and none as worse at 24 months. The mean improvement in Lysholm knee score for knee instability was 68 points (standard deviation 10). Ligamentous laxity was seen in 17 (55 %) of individuals. In this subset, 12 were graded as excellent, 4 as good and 1 as fair. The mean improvement in patellar height was 11 % at 3 months follow-up. All knees had a stable graft fixation with one re-dislocation following trauma. Conclusions: We propose a minimally invasive technique to reconstruct the MPFL using an artificial ligament allowing early mobilization without bracing. This study indicates the procedure is safe, with a low risk of re-dislocation in all grades of instability