Systematic Review of Medial Patellofemoral Ligament Reconstruction Techniques: Comparison of Patellar Bone Socket and Cortical Surface Fixation Techniques

Purpose: To compare patellar bone socket and cortical surface fixation techniques for isolated medial patellofemoral ligament (MPFL)reconstruction and determine whether there was a difference in (1)complication rates, including fracture of the patella; (2)redislocation rates; or (3)patient-reported outcomes. Methods: A literature search was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)guidelines. We included patients who underwent isolated MPFL reconstruction for recurrent patellar instability. Patients with confirmed concomitant or prior ipsilateral knee procedures, multiligament injury, or less than 3 months of follow-up were excluded. Risk-of-bias assessment was performed using the Methodological Index for Non-randomized Studies (MINORS)system. Studies were classified by surgical technique (patellar bone socket group [group S]vs cortical fixation group [group F]), and complications, redislocations, and patient-reported outcomes were collected. Results: A total of 29 studies yielded 981 patients with MPFL reconstruction for inclusion. Of the patients, 620 underwent a patellar bone socket technique and 361 underwent a cortical fixation technique. Patients ranged in age from 11 to 68 years. Patellar fracture rates ranged from 0% to 17% in group S and were 0% in all group F studies. Mean Kujala scores ranged from 83.5 to 93.6 in group S and from 84.4 to 94.5 in group F. Mean Lysholm scores ranged from 84.6 to 91.7 in group S and from 83.5 to 95 in group F. Redislocation rates ranged from 0% to 21% in group S and from 0% to 13% in group F. Although heterogeneous in nature, complication rates ranged from 0% to 28% in group S and from 0% to 4% in group F. Conclusions: MPFL reconstruction techniques with patellar bone sockets showed a larger range of complication rates than cortical fixation techniques, although overall, complications remained uncommon. Clinically, the bone socket group had comparable postoperative redislocation rates and patient outcomes to the group treated with cortical fixation techniques. Level of Evidence: Level IV, systematic review of Level I through IV studies.