Original article
Patellofemoral instability in skeletally immature patients
Sara Alexandra Fernandes Machadoa,b,c,, , Rui Alexandre Peixoto Pintoa,c,1, Artur Jorge Afonso Martins Antunesa, Paulo Alexandre Ribeiro de Oliveiraa,c,2
a Orthopedic Department, Centro Hospitalar de São João, Alameda Prof. Hernâni Monteiro, Porto, Portugal
b Anatomy Department, Oporto Medical School, Al. Prof. Hernâni Monteiro, Porto, Portugal
c Orthopedic Department, Oporto Medical School, Al. Prof. Hernâni Monteiro, Porto, Portugal
Received 31 October 2016, Accepted 21 December 2016

Patellofemoral instability is a common cause of knee disability. Acute patellofemoral dislocation is the most common acute knee disorder in skeletally immature patients. In this group, the incidence of patellofemoral dislocation is approximately 43 per 100,000 individuals.

The precise objective addressed in the paper

Medial patellofemoral ligament (MPFL) reconstruction has a significant role in the treatment of patellofemoral instability in skeletally immature patients. We evaluated the medium and long-term results results of MPFL reconstruction as the sole method of patellofemoral instability treatment and their relationship with the presence of other potentially associated factors.


We conducted a prospective study with 35 young patients who underwent the same surgical technique between 2002 and 2009. Age, gender, patellar tilt, patella height, TT-TG, trochlear dysplasia, the Kujala score and the Tegner activity score were evaluated. Statistical analysis used SPSS® 20.


The mean age of the patients was 15.9 years. High patella was observed in 10% of patients. All patients had TT-TG within a normal range. Trochlear dysplasia was found in 80% of the patients: 40% had Dejour's type A; 34% type B; 20% type C and 6% type D. The medium-term Kujala score (84±9) significantly improved compared to the pre-operative score (54±11). However, a decline in the long-term (78±3) score was observed. The Tegner activity score showed a significant decrease. The long-term results were significantly lower when patients had trochlear dysplasia type B to D.


A decade after isolated MPFL reconstruction, results remained satisfactory. Patients with trochlear dysplasia types B to D may benefit from associated trochleoplasty in a second intervention.

Patellofemoral, Instability, Immature, Patients

Open Access

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Porto Biomedical Journal is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

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