Purpose
To systematically review the incidence of complications following primary MPFL reconstruction for recurrent patellar instability.
Study Design: Systematic Review; Level of Evidence IV.
Methods
A literature search was conducted by querying PubMed and Scopus databases from database inception through August 2022 according to the 2020 PRISMA guidelines using the terms ‘Medial Patellofemoral Ligament’, ‘MPFL’, ‘reconstruction’, ‘patellar’, and ‘instability’. Inclusion criteria included studies reporting complications following primary MPFL reconstruction for recurrent patellar instability. Exclusion criteria consisted of studies reporting on patients undergoing concurrent osteotomy procedures, revision reconstruction, and biomechanical or anatomic studies. The overall incidence of specific complications was estimated from the pooled sample of the included studies.
Results
Twenty-eight studies, consisting of 1478 patients (n=1521 knees), with a mean age of 23.3 years (mean range, 19 – 34.3 years) were identified. The overall incidence of complications was 12.3% (n=187/1521). Failure was estimated in 2% (range, 0% - 10.7%) of knees, while patellar fractures occurred in 1.1% (range, 0% - 8.3%) of knees, primarily in patients treated with a full-length transverse tunnel or two-tunnel techniques. All patellar fractures occurred in patients with patellar tunnels ranging from 4.5 mm to 6.0 mm in diameter. The development of patellofemoral degenerative changes was reported in a single study, with a calculated incidence of 23.9%. The incidence of postoperative knee stiffness/range of motion deficit was 3% (range, 0% - 20%). Total pain instances, including persistent anterior knee pain, were reported in 8.0% (range, 0% - 40.6%) of knees.
Conclusion
Complications following primary MPFL reconstruction were recorded in 12.3% of knees, primarily consisting of the development of patellofemoral degenerative changes. Failure was reported in 2% of knees, while patellar fractures were reported in 1.1% of knees. Fractures primarily occurred with a full-length transverse tunnel or two-tunnel techniques, while all fractures occurred with patellar tunnels ranging from 4.5 mm to 6.0 mm in diameter.