Several factors led to lower quality of life outcomes after MPFL reconstruction
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Published results showed bilateral symptoms, femoral tunnel position and age at first dislocation were statistically significant predictors of lower postoperative quality of life scores among patients who underwent isolated medial patellofemoral ligament reconstruction. However, researchers found no anatomic risk factors predicted quality of life outcomes.
To identify predictors of disease-specific quality of life (QoL) outcomes in 224 patients who underwent isolated medial patellofemoral ligament (MPFL) reconstruction for treatment of symptomatic lateral patellofemoral instability, Laurie A. Hiemstra, MD, PhD, FRCSC, and colleagues collected demographic data and measured pathoanatomic risk factors, including the presence of high-grade trochlear dysplasia, tibial tubercle-trochlear groove (TT-TG) distance, patella alta ratio, Beighton score and patellar tilt. Researchers also measured femoral tunnel position accuracy.
Results showed the mean age of first patellar dislocation was 15.7 years. Overall, 41.4% of patients had bilateral instability, according to results. Researchers found 41% and 46% of patients had high- and low-grade dysplasia, respectively. A TT-TG distance of 18 mm or more was found in 17% of patients, and 22% of patients had a Caton-Deschamps ratio of 1.2 or greater, according to results. Researchers noted 38% of patients had a positive Beighton score, 46% of patients had knee hyperextension, 25% of patients had femoral internal rotation and 85% of patients had a patellar chondral lesion.
A 2 years postoperatively, results showed patients had a mean Banff Patellofemoral Instability Instrument score of 67.1. In an assessment of individual variables, researchers found statistically significant predictors of lower QoL scores included bilateral symptoms, older age at first dislocation and femoral tunnel position 0.10 mm from Schöttle’s point.
“This well powered regression analysis found that the presence of bilateral symptoms, femoral tunnel position and age at first dislocation were predictors of lower quality of life scores following isolated MPFL reconstruction. The inability of this study to identify pathoanatomic features, such as patella alta and trochlear dysplasia, is disappointing,” Hiemstra told Healio.com/Orthopedics. “It may be that the lack of precise and reliable classification systems for these risky pathoanatomic features reduced the opportunity to statistically identify if these influence quality of life outcomes. In addition, the range of combinations of demographic and pathoanatomic characteristics that patellofemoral instability patients present with may require a substantially larger population in order to flesh out these relationships given how many factors influence disease-specific quality of life scores.” – by Casey Tingle
Disclosures: Hiemstra reports she has completed educational consultancy work for ConMed Corporation, Sanofi-Aventis Canada, Pendopharm Canada and Concession Medical Canada. Please see the study for a list of all other authors’ relevant financial disclosures.
Perspective
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Seth L. Sherman, MD
Isolated medial patellofemoral ligament reconstruction (MPFL-R) has becomes a workhorse in the treatment of symptomatic patella instability. The influence of risky pathoanatomy and patient factors on clinical outcome following this procedure remains controversial. Hiemstra and colleagues evaluated 224 patients following isolated MPFL-R. In multivariate analysis, the authors found that bilateral symptoms (P = .004), higher age at first dislocation (P = .024), and femoral tunnel position of greater than 10 mm from the Schottle point (P = .042) were statistically significant predictors of lower BPII quality of life scores.
Strengths include large numbers with medium follow-up and an experienced team performing standardized techniques. Two non-modifiable risk factors (bilateral symptoms, higher age at first dislocation) influenced quality of life. This is helpful for patient counseling and presurgical planning. Further investigation could identify other targets for intervention (ie, presence of chondrosis) in these challenging subgroups. Aberrant femoral MPFL tunnel position was also found to be a predictor of reduced quality of life following isolated MPFL-R. This is a modifiable risk factor under surgeon control and highlights the importance of meticulous technique for patient outcome.
Weaknesses include non-controlled design and no analysis of other outcome tools (ie, other subjective scores, objective exam, activity scores, imaging). The study also excluded many patients with extremes of “risky anatomy” who underwent combined bony and soft tissue procedures. This tempers the strength of the conclusion that no anatomic risk factors were predictive of quality of life.
Overall, the authors demonstrate that isolated MPFL-R is a successful surgery that improves quality of life. Awareness of high-risk groups (bilateral, older age) and meticulous surgical technique can optimize outcome.
References:
Erickson BJ, et. al. Am J Sports Med.2019; doi:10.1177/0363546519835800.
Liu JN, et. al. Am J Sports Med. 2018; doi:10.1177/0363546517732045.
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.
Department of orthopedic surgery
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