Is femoral trochlear dysplasia related to global joint hypermobility?

Background: Hypermobility is a known risk factor for patellar instability. In this study, we hypothesized that a significant relationship exists between global joint hypermobility and trochlear dysplasia.

Methods: Follow-up patients from the shoulder department of our institution with global joint hypermobility (Group 1, n = 42) and healthy volunteers (Group 2, n = 42) without known knee complaints were included in our study. All participants underwent knee magnetic resonance imaging (MRI) for the evaluation of possible trochlear dysplasia, and the measurements included lateral trochlear inclination; trochlear facet asymmetry; the depth of the trochlear groove; condylar asymmetry; lateralization of the patella; sulcus angle; and the lateral, medial and central trochlear height. The Dejour classification was also assessed.

Results: The age and gender distributions of the groups were similar (p > 0.05). The radiological evaluations revealed that the lateral trochlear inclination (p < 0.001), trochlear facet asymmetry (p < 0.001), depth of the trochlear groove (p < 0.001), lateralization of the patella (p < 0.001), sulcus angle (p < 0.001), and central trochlear height (p < 0.001) were significantly different between the two groups. The condylar asymmetry and lateral and femoral condylar height parameters were similar between the groups (p = 0.297, p = 0.890 and p = 0.521, respectively). According to the Dejour classification, 39 patients had dysplasia in Group 1, whereas dysplasia was detected in only 4 of the participants in Group 2.

Conclusions: Our study revealed that most of the trochlear dysplasia criteria were met in patients with global joint hypermobility. In addition to a clinical patellofemoral examination, the precise radiological evaluation of the joint is beneficial in patellofemoral instability patients with concomitant hypermobility. Patient cohort of this study was consist of patients underwent shoulder surgery.