Relation of the chondromalatia patellae to proximal tibial anatomical parameters, assessed with MRI

Tabary, Mohammadreza; Esfahani, Azadehsadat; Nouraie, Mehdi; Babaei, Mohammad Reza; Khoshdel, Ali Reza; Araghi, Farnaz; Shahrezaee, Mostafa

doi:10.2478/raon-2020-0021

Figures & Tables

(A, B, C) Axial PD fat sat MR images illustrating lateral trochlear inclination, trochlear depth, and lateral patellofemoral angle. (Lateral trochlear inclination, z: the angle formed between the lateral trochlear facet and a parallel line to the line connecting the posterior-most cortical surfaces of the femoral condyles; Trochlear depth, y: the distance between the deepest point of trochlear sulcus and the line connecting the anterior points of the medial and lateral condyles; Lateral patellar tilt angle, x: the angle between the line parallel to the patellar lateral facet and the line connecting the most posterior parts of femoral condyles)

(A, B) Sagittal T1-Weighted MR images illustrating medial tibial slope and Insall-Salvati index. (Medial tibial slope, z: the angle formed between the line running along the tibial slope of the medial tibial condyle and the perpendicular line to the tibial axis; Insall-Salvati index: the ratio of x to y; x, the length of patellar tendon and y, the greatest diagonal length of patella)

Measurements of nonsignificant MRI parameters in the final model. (A) Axial MRI plane of the knee showing Intercondylar notch angle (INA) and Intercondylar depth (ID): The posterior bicondylar line is drawn. ID is the distance between top of the notch to the bi-epicondylar line. Intercondylar notch angle is defined as the angle formed by the 2 lines going from the top of the notch to the most inferior aspect of the notch at the medial and lateral condyles; (B) Axial MRI plane of the knee showing Intercondylar Width (IW), Medial condyle width (MCW), and Lateral condyle width (LCW): IW is the distance between the medial and lateral femoral condyle walls at the anterior third of the intercondylar depth (the middle line), the other two distances in this axial cut represent LCW, and MCW; (C) Sagittal MRI plane of the knee showing anterior tibial slope (ATS): At first the tibial axis is drawn by joining to midpoints between the anterior and posterior cortex of the tibial diaphysis with at least 5cm distance from each other. The anterior tibial slope is then defined as the angle between a perpendicular line (inferior line) to the longitudinal axis and a line passing through the anterior cruciate ligament tibial footprint (superior line); (D) Sagittal MRI plane of the knee showing coronal tibial slope (CTS): The coronal tibial slope is defined as the angle between a line joining the highest points on the medial and lateral aspects of the tibial plateau (inferior horizontal line) and a perpendicular line (superior horizontal white line) to the longitudinal axis as mentioned above; (E) Sagittal MRI plane of the knee showing lateral tibial slope (LTS): the angle formed between the line running along the tibial slope of the medial tibial condyle and the perpendicular line to the tibial axis; (F) Sagittal MRI plane of the knee showing patellar tibial tendon shaft angle (PTTS angle): PTTS angle is measured as the angle between Proximal tibial anatomical axis described above and patellar tendon axis in the mid-sagittal section; (G) Coronal MRI plane of the knee showing notch width index (NWI): first Bicondylar width parallel to the joint line at the level of popliteal groove is measured (1). Then notch width is measured at the level of popliteal groove, using the line joining the innermost margins of the femoral condyles at the borders of the intercondylar notch (2). The NWI is ratio of 2/1; (H) Axial MRI plane of the knee showing sulcus angle (SA): The angle formed between the medial and lateral trochlear facets; (I) Axial MRI plane of the knee showing patellar facet angle (PFA): the angle between two line connecting the central ridge to the middle of patellar facets; (J) Axial MRI plane of the knee showing patellofemoral index (PFI): the ratio of medial to lateral interspaces; (K, L) Axial MRI plane of the knee showing tibial tuberosity trochlear groove distance (TTTG): posterior line was drawn at posterior border of femoral condyles. A vertical line is drawn at trochlear groove and the other parallel line is drawn along the tibial tuberosity that transferred to this level. Distance between the two lines is measured as TT-TG; (M) Sagittal MRI plane of the knee showing Patella-patellar tendon angle (P-PT angle): The P–PT angle was defined as the angle between the upper patellar pole and the lower patellar pole, and the tibial tuberosity; (N) Sagittal MRI plane of the knee showing Patellotrochlear index (PTI): it is defined as the length of patellar cartilage overlapping the trochlear cartilage divided by length of patellar cartilage; (O) Axial MRI plane of the knee showing medial trochlear inclination (MTI): the angle formed between the medial trochlear facet and a parallel line to the line connecting the posterior-most cortical surfaces of the femoral condyles.

Predictive model for chondromalacia including MRI measurements

MRI measurements	Odds ratio	95% CI	P-value	Intra-rater reliability	Contribution of any increase in this parameter to chondromalacia
LTI	1.15	1.03–1.30	0.014	0.992	Increases disease probability
LPTA	1.13	1.02–1.26	0.018	0.996	Increases disease probability
MTS	0.85	0.73–0.98	0.026	0.997	Decreases disease probability
TD	0.06	0.02–0.17	0.000	0.995	Decreases disease probability
Age	1.10	1.02–1.20	0.015	-	Increases disease probability

MRI measurements of the control patients versus chondromalacia cases

MRI Measurements	Median (IQR)		Odds ratio	95% CI^{IQR represents 25^th–75^th interquartile range, 95% CI represents 95% confidence interval for odds ratio}	P-value
MRI Measurements	Control	Case	Odds ratio		P-value
INA (degree)	52.0 (48.0–57.0)	53.0 (48.0–56.0)	1.00	0.96–1.05	0.863
IW (mm)	21.5 (20.1–23.4)	20.3 (19.0–21.7)	0.77	0.67–0.88	< 0.001
ID (mm)	28.2 (26.7–29.8)	25.9 (26.7–29.8)	0.76	0.68–0.85	< 0.001
MCW (mm)	26.5 (24.9–28.5)	24.8 (23.2–26.7)	0.79	0.70–0.88	< 0.001
LCW (mm)	27.2 (25.5–28.8)	24.4 (23.3–26.1)	0.77	0.69–0.86	< 0.001
ATS (degree)	8.0 (5.5–11.5)	8.0 (6.0–10.5)	1.01	0.94–1.09	0.727
CTS (degree)	3.5 (2.0–5.0)	4.0 (2.5–5.2)	1.13	0.96–1.32	0.144
MTS (degree)	7.5 (5.2–9.5)	7.0 (4.5–9.5)	0.95	0.87–1.04	0.252
LTS (degree)	5.5 (3.5–7.5)	5.5 (3.5–7.5)	0.96	0.88–1.05	0.448
PTTS angle (degree)	27.0 (23.0–30.0)	27.0 (24.0–30.0)	1.01	0.95–1.08	0.46
NWI	0.29 (0.27–0.31)	0.29 (0.27–0.31)	0.18	0.00–6399.00	0.749
TD (mm)	5.30 (4.82–5.87)	4.04 (3.51–4.60)	0.14	0.08–0.24	< 0.001
SA (degree)	140.0 (134.0–145.0)	142.0 (137.0–150.0)	1.04	1.01–1.08	0.009
LTI (degree)	20.0 (18.0–23.0)	20.0 (17.5–24.0)	0.99	0.93–1.05	0.683
MTI (degree)	18.0 (15.0–21.0)	16.0 (13.5–20)	0.93	0.89–0.99	0.020
LPTA (degree)	13.0 (10.0–16.0)	14.0 (10.5–17.0)	1.03	0.97–1.08	0.294
PFA (degree)	138.0 (133.0–142.0)	136.0 (132.5–141.0)	0.97	0.93–1.01	0.160
PFI	1.14 (1.01–1.35)	1.32 (1.07–1.59)	3.02	1.37–6.65	0.006
TTTG (mm)	12.5 (10.2–15.2)	12.3 (10.5–16.1)	1.01	0.95–1.09	0.603
SCF (mm)	20.5 (17.3–25.3)	26.7 (21.7–34.8)	1.14	1.09–1.19	< 0.001
CWI	0.52 (0.50–0.54)	0.52 (0.50–0.54)	0.76	0.00–3481.00	0.949
SWI	0.57 (0.54–0.59)	0.56 (0.54–0.58)	0.01	0.00–34.80	0.270
P-PT angle (degree)	140.5 (137.0–144.0)	140.0 (137.5–143.5)	0.99	0.93–1.05	0.802
ISI	0.98 (0.89–1.07)	1.00 (0.89–1.14)	4.62	0.60–35.20	0.139
PTI	0.31 (0.26–0.36)	0.30 (0.25–0.35)	0.04	0.00–2.21	0.115

Predictive model for chondromalacia severity including MRI measurements

MRI measurements	Odds ratio	95%CI	P-value	Intra-rater reliability	Contribution of any increase in this parameter to chondromalacia severity
ISI	75.89	2.17–2652.69	0.017	0.997	Increases disease grade
Age	1.14	1.07–1.21	0.000	-	Increase disease grade

Relation of the chondromalatia patellae to proximal tibial anatomical parameters, assessed with MRI

Figures & Tables

Figure 1

Figure 2

Figure 3

Predictive model for chondromalacia including MRI measurements

MRI measurements of the control patients versus chondromalacia cases

Predictive model for chondromalacia severity including MRI measurements

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