Comparison of Radiological Parameters between Normal and Patellar Dislocation Groups in Korean Population: A Rotational Profile CT-Based Study

Abstract

PurposePatellofemoral instability is a common cause of anterior knee pain in adolescents and young adults. Most normal and pathological values for diagnosing patellofemoral instability are based on Western literature. We conducted this radiological study to determine normal values for different patellofemoral parameters in a Korean population and to evaluate their usefulness in diagnosis.Materials and MethodsWe retrospectively reviewed the rotational profile computerized tomography (CT) scans of the patellar dislocation and control groups. Trochlear, patellar, rotational profile, and trochleo-patellar alignment parameters were compared between the groups. Receiver operating characteristic curves were drawn for significant parameters, and sensitivity and specificity were calculated for the cut-off values.ResultsThere were 48 patients in the patellar dislocation group and 87 patients in the control group. In the control group and patellar dislocation group, the mean sulcus angle was 132.5° and 143.3°, respectively, trochlear depth was 6.04 mm and 3.6 mm, bisect offset was 56.4% and 99.9%, lateral patellar tilting was 9.8° and 19.2°, patellar facet asymmetry was 63.5% and 45.16%, and the tibial tuberosity-trochlear groove (TT-TG) distance was 10.91 mm and 27.16 mm, respectively.ConclusionsThe trochlear depth, bisect offset, patella tilting, and TT-TG distance were parameters that significantly contributed to patellar instability. Rotational profile CT can be considered a good diagnostic tool to assess all these parameters that help to identify anatomical aberration resulting in patellofemoral instability, thereby helping in formulating the most effective treatment plan.

The Difference between Cartilaginous and Bony Sulcus Angles for Patients with or without Patellofemoral Instability: A Systematic Review and Meta-Analysis

“…[9][10][11][12][13][14][15][16][17][18][19] These included six publications that compared between cartilaginous and bony sulcus angles, 9,11,13,15,17,18 and eight publications that compared between sulcus angles for patients with and without patellofemoral instability. 9,10,12-14, 16,18,19 Collectively, these included a total of Table 1 Details of the studies included in the review 1,204 patients, of which 693 had patellofemoral instability, while 511 did not have patellofemoral instability. The details of the study design and patient population of all the studies are reported in ►Table 1.…”

“…2 This has led to two commonly used sulcus angle measurements, which are the cartilaginous sulcus angle and the bony sulcus angle. [9][10][11][12][13][14][15][16][17][18][19] Multiple studies have been conducted to analyze whether the cartilaginous and bony sulcus angles are interchangeable or different. All six publications included in the review reported the cartilaginous sulcus angle to be greater than the bony sulcus angle.…”

“…A total of eight publications compared between patients with and without patellofemoral instability. 9,10,[12][13][14]16,18,19 These included six publications that compared cartilaginous sulcus angle 9,10,12,13,18,19 and five publications that compared bony sulcus angle. 9,13,14,16,18 All eight publications reported the sulcus angle to be greater in patients with patellofemoral instability as compared with those without patellofemoral instability (►Figs.…”

“…5). 9,10,[12][13][14]16,18,19 Both the cartilaginous and bony sulcus angles could therefore be used to differentiate between patients with and without trochlear dysplasia.…”

“…2 Two different methods of sulcus angle measurements have been widely used for CT and MRI. [9][10][11][12][13][14][15][16][17][18][19] These are commonly known as the cartilaginous sulcus angle and bony sulcus angle which use cartilaginous and bony landmarks, respectively. [9][10][11][12][13][14][15][16][17][18][19] However, there is a lack of conclusive data in the current literature as to whether these parameters, originally designed for radiographs, can be applied in their entirety to CT and MRI.…”