Factors Associated With an Increased Risk of Recurrence After a First-Time Patellar Dislocation: A Systematic Review and Meta-analysis

Abstract

Background: Recurrent dislocations after a first-time lateral patellar dislocation may occur in more than 50% of patients and can cause long-term disability. Many factors have been suggested to influence the risk of recurrence. Purpose: To systematically review and quantitatively synthesize the literature for factors associated with an increased risk of recurrence after a first-time patellar dislocation. Study Design: Systematic review and meta-analysis of observational studies. Methods: A total of 4 electronic databases were searched to identify relevant studies published before February 7, 2019. A quality assessment was performed with the National Heart, Lung, and Bone Institute quality assessment score. Factors assessed for their effect on the recurrence rate were documented, and the rates of recurrence were compared. Pooled dichotomous data were analyzed using random-effects meta-analysis with odds ratios (ORs). Results: A total of 17 studies met the criteria for inclusion. The overall rate of recurrent dislocations after a first-time lateral patellar dislocation was 33.6%. An increased risk of recurrence was reported in patients with a younger age (OR, 2.61; P < .00001), open physes (OR, 2.72; P < .00001), trochlear dysplasia (OR, 4.15; P = .009), an elevated tibial tuberosity–trochlear groove (TT-TG) distance (OR, 2.87; P < .00001), and patella alta (OR, 2.38; P = .004). Sex, patterns of medial patellofemoral ligament injury, and history of contralateral dislocations were not found to be associated with an increased recurrence rate ( P≥ .05). In studies that reported on the presence of multiple risk factors, recurrence rates were 7.7% to 13.8% when no risk factors were present but increased to 29.6% to 60.2% when 2 risk factors were present and to 70.4% to 78.5% when 3 risk factors were present. Conclusion: Younger age, open physes, trochlear dysplasia, elevated TT-TG distance, and patella alta were key risk factors for the recurrence of lateral patellar dislocations. Despite being not infrequently cited as risk factors, patient sex and a history of contralateral dislocations were not found to be significant risk factors. The presence of multiple risk factors increased the risk, and the development of predictive instability scores in large patient cohorts using all established risk factors should be a focus of future studies.

Evaluation of risk correlation between recurrence of patellar dislocation and damage to the medial patellofemoral ligament in different sites caused by primary patellar dislocation by MRI: a meta-analysis

“…A meta-analysis compared the difference of redislocation between mild and severe trochlear abnormity, based on Dejour's classification of trochlear dysplasia, and found that the probability of recurrent patellar dislocation in severe trochlear dysplasia was 1.41 times higher than that in mild cases, and the probability of recurrent patellar dislocation in patients with femoral trochlear dysplasia is 4.15 times higher than that in people with normal trochlear development. These results further confirmed the value of femoral trochlear dysplasia in predicting recurrent patellar dislocation [1]. However, the relationship between sulcus angle and recurrent patellar dislocation was not shown in this meta-analysis.…”

“…Patellar dislocation is a common traumatic disease, with the incidence of primary patellar dislocation in the population being 23-42 per 100,000 per year. The probability of recurrent dislocation in these patients after conservative treatment is 17-66%, and the younger the patient, the higher the probability of recurrence [1][2][3][4][5]. It is believed that patellar dislocation is a multifactorial disease with the combined effects of bone anatomical abnormality and abnormality in the soft tissue structure that maintains the stability of the patellofemoral joint.…”

Normalisation of Patella Alta with MPFL Reconstruction Reduces the Prevalence of Risk Factors Associated With Recurrent Patella Dislocations - A Prospective Cross Sectional Study

“…The included studies had variations in the de nitions of risk factors; patella alta de ned with CD ratios ranging from >1.2 to 1.45, and IS ratio >1.2 to 1.3; and elevated TT-TG distance ranging from >14 to 20 mm. Based on the above risk factors, they reported a recurrence risk of 7.7-13.8% with no abnormal risk factors, 29.6-60.2% with 2 abnormal risk factors, and 70.4-78.5% with 3 abnormal risk factors present[15]. A majority of our patient had 2 or more abnormal risk factors (69.7%), and 11 patients (33.3%) had at least 3 risk factors.…”

“…The risk factors we chose for our cohort were the predictive factors for recurrence identi ed in the metaanalysis by Huntington et al [15]. This represents the latest meta-analysis to study factors associated with the risk of recurrence for patella dislocations.…”

“…Utilising these proposed risk factors, several studies have developed clinical prediction models [12][13][14]. In a meta-analysis of risk factors associated with recurrence for dislocation, Huntington et al reported an overall recurrent dislocation rate of 33.6% [15]. The meta-analysis of 12 studies found younger age, open physes, trochlear dysplasia, elevated TT-TG distance, and patella alta to be signi cant risk factors, with a magni ed risk of recurrence as the number of abnormal risk factors increased.…”