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Patella alta, preoperative positive J-sign may be risk factors for failure after MPFL reconstruction
Isolated, medial patellofemoral ligament reconstruction may be safe and efficient for the treatment of recurrent patellar instability, according to recently published results.
Researchers identified 211 patients who underwent medial patellofemoral ligament reconstruction. The mean follow-up was 5.8 years. The Kujala score assessment of patellar tracking and radiographic features, such as trochlear dysplasia according to Dejour classification, patellar height with the Caton-Deschamps index, tibial tubercle-trochlear groove distance and patellar tilt, were included in the preoperative assessment. Postoperatively, investigators assessed the Kujala score. A postoperative patellar dislocation or surgical revision for recurrent patellar instability was considered a failure.
Results showed a position J-sign in 27% of patients. There were 93% of patients with trochlear dysplasia. The mean Caton-Deschamps was 1.2. The mean tibial tubercle-trochlear groove distance was 15 mm, and the mean patellar tilt was 23°. The mean Kujala score improved from 56.1 preoperatively to 88.8 postoperatively.
There were 10 failures reported which needed surgical revision due to recurrent patellar instability. Univariate and multivariate analyses demonstrated patellar alta and a preoperative positive J-sign were preoperative risk factors for failure. – by Monica Jaramillo
Disclosures: Erickson reports he receives education payments from Smith & Nephew and education and hospitality payments from DePuy. Please see the full study for a list of all other authors’ relevant financial disclosures.
Perspective
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Medial patellofemoral ligament reconstruction is the gold standard for soft tissue stabilization following recurrent patella dislocation. Controversy remains regarding the threshold for adding concomitant procedures to MPFL reconstruction. Sappey-Marinier and colleagues performed a retrospective review of prospectively collected data on 239 isolated MPFL reconstructions (average follow-up 5.8 years). Kujala improved from 56.1 to 88.8 (P< .001), with 94% return to same level of sport. There was a 4.7% revision rate. Risk factors for failure included patella alta (Caton-Deschamps index [CDI] >1.3, odds ratio 4.9, P=.02) and a positive preoperative J-sign (odds ratio 3.9, P= .04). There was a correlation between preoperative J-sign and severe trochlear dysplasia (OR 16.9, P< .001)
Strengths include large numbers with medium follow-up and standardized surgical regimen performed by experienced surgeons. Weaknesses include inherent bias associated with nonrandomized or controlled design, retrospective review, lack of complete clinical and radiographic results and 11.7% loss to follow-up.
Overall, soft tissue stabilization appears safe and effective for the vast majority of patients with recurrent patella instability. Pre-surgical risk stratification may help to identify those at higher risk of failure (ie, CDI >1.3, preoperative J-sign with severe trochlear dysplasia) who warrant consideration for concomitant procedures. Prospective studies are ongoing to provide more definitive guidance.
References:
Erickson BJ, et al. Am J Sports Med. 2019;doi:10.1177/0363546519835800.
Liu JN, et al. Am J Sports Med. 2018;doi:10.1177/0363546517745625.
Kita K, et al. Am J Sports Med. 2015;doi:10.1177/0363546515606102.
Sappey-Marinier E, et al. Am J Sports Med. 2019;doi:10.1177/0363546519838405.
Co-division director of sports medicine
Columbia, Missouri