Isolated medial patellofemoral ligament reconstruction for the treatment of acute or recurrent patellar instability: a systematic review and meta-analysis.

Background

A patellar dislocation is a common knee injury in the young, athletic patient population. Medial patellofemoral ligament (MPFL) reconstruction is now considered to be the preferred treatment for acute and recurrent patellofemoral instability. Several surgical techniques have been reported; however, without consensus regarding the optimal reconstruction.
This systematic review and meta-analysis covers the patellar re-dislocation rate, improvement in patient-reported outcomes and complication rates of different methods of MPFL reconstruction as reported in the literature.

Hypothesis

MPFL reconstruction for acute or recurrent patellar instability leads to improved Kujala scores and low re-dislocation rate independently of the chosen MPFL reconstruction technique.

Study design:
Meta-analysis.

Methods

A literature search was performed using Embase, Medline (Ovid) and Scopus following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We included studies evaluating isolated MPFL reconstruction for first-time and recurrent patellar instability with a minimum follow-up of 24 months if they reported patellar re-dislocation rate, complications and the validated Kujala patient-reported outcome score.
Studies were classified by surgical technique and systematically assessed for quality and level of evidence.

Results

Twenty-tree studies were included with a total of 919 patients with an average age of 24.9 years at time of surgery. The large majority of patients (n=802) received autograft tendons for reconstruction (87.27%) and femoral fixation was performed using an interference screw in 838 patients (91.19%).
The mean improvement in the Kujala score in suture anchor versus transosseous patellar fixation technique was respectively 31.74 (95% CI, [20.08-43.40]) and 33.43 (95% CI, [24.50-42.37]), p = >0,001.
Only one patellar fracture was noted following a transosseous patellar fixation technique.
Single and double-bundle MPFL reconstructions yielded similar outcomes regarding mean improvement in the Kujala score. The pooled postoperative re-dislocation rate from all series showed a mean of 1.70% (95% CI, [0.00%-9.53%]). In contrast, clearly higher re-dislocation rate is noted upon single-bundle reconstruction; 2.94% (95% CI, [0.00%-14.54%]).

Conclusions

This meta-analysis shows that isolated MPFL reconstruction for acute or recurrent patellar dislocation results in significant improvement in Kujala scores and very low re-dislocation rates. The various MPFL reconstruction techniques show no significant difference in clinical outcome or complication rate. Double-bundle autograft tendon reconstruction with femoral interference screw fixation and patellar fixation using hardware is most often used with good results and low re-dislocation rate. Randomized controlled trials would be needed to determine superiority of a particular MPFL reconstruction technique.

Level of evidence: Level IV, systematic review of Level I through IV studies