Normative data of frontal plane patellar alignment in athletes
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Accepted Manuscript
Normative data of frontal plane patellar alignment in athletes
Luciana De Michelis Mendonça, PT, MSc Juliana Melo Ocarino, PT, ScD NatáliaFranco Netto Bittencourt, PT, MSc Thiago Ribeiro Teles Santos, PT, MSc RafaelAlmeida Barreto, PT, BPT Sérgio Teixeira Fonseca, PT, ScD
PII: S1466-853X(14)00076-5
DOI: 10.1016/j.ptsp.2014.09.003
Reference: YPTSP 630
To appear in: Physical Therapy in Sport
Received Date: 11 December 2013
Revised Date: 15 April 2014
Accepted Date: 12 September 2014
Please cite this article as: De Michelis Mendonça, L., Ocarino, J.M., Netto Bittencourt, N.F., TelesSantos, T.R., Barreto, R.A., Fonseca, S.T., Normative data of frontal plane patellar alignment in athletes,Physical Therapy in Sport (2014), doi: 10.1016/j.ptsp.2014.09.003.
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NORMATIVE DATA OF FRONTAL PLANE PATELLAR ALIGNMENT 1
IN ATHLETES 2
Luciana De Michelis Mendonça, PT, MSca,b, Juliana Melo Ocarino, PT, 3
ScDa,c, Natália Franco Netto Bittencourt, PT, MSca,d, Thiago Ribeiro Teles 4
Santos, PT, MSca, Rafael Almeida Barreto, PT, BPTa, Sérgio Teixeira 5
Fonseca, PT, ScDa,c. 6
a Laboratory of Sports Injuries and Prevention (LAPREV) – Universidade 7
Federal de Minas Gerais, Belo Horizonte, Minas Gerais (MG), Brazil – CEP 8
31270-901 9
b Instituto Superior de Ciências da Saúde – Belo Horizonte, MG – Brazil – 10
CEP 30494-270 11
c Departamento de Fisioterapia – Escola de Educação Física, Fisioterapia e 12
Terapia Ocupacional – Universidade Federal de Minas Gerais – Belo 13
Horizonte, MG – Brazil – CEP 31270-901 14
d Minas Tenis Clube – Belo Horizonte, MG – Brazil – CEP 30112-011 15
Corresponding author (and requests for reprints): Sérgio Teixeira Fonseca – 16
Escola de Educação Física, Fisioterapia e Terapia Ocupacional - Av. Pres. 17
Antônio Carlos, 6627 Campus - Pampulha - Belo Horizonte - MG - CEP 18
31270-901 - Universidade Federal de Minas Gerais – Brazil 19
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NORMATIVE DATA OF FRONTAL PLANE PATELLAR ALIGNMENT 1
IN ATHLETES 2
ABSTRACT 3
Objective: the objective of this study was to provide normative data of frontal 4
plane patellar alignment according to McConnell and Arno angles, verify the 5
association between theses angles and identify the presence of patellar rotation 6
in different sports modalities. Design: cross-sectional. Participants: Nine 7
participants (18 knees) were assessed in a preliminary study to verify the intra 8
and inter-examiner reliabilities of the patellar alignment measures. In the main 9
study, 230 volleyball, basketball, gymnastics and soccer athletes (460 knees) 10
were evaluated in order to obtain normative data of patellar alignment. Main 11
outcome measures: frontal plane patellar alignment (McConnell and Arno 12
angles) measured in standing position by means of photogrammetry. Results: 13
The standardized method demonstrated intra e inter-examiner reliability 14
coefficients varying from (.85 to .98). The mean McConnell and Arno angles 15
were 2.05o (±5.9) and 2.89o (±7.57), respectively. It was observed a low 16
association (r=.189, p<.000) between these angles. There was difference in 17
distribution of medial and lateral rotations, according to McConnell angle, 18
between sports modalities (p<.014). Conclusions: The proposed procedure for 19
measuring patellar alignment according to McConnell and Arno angles proved 20
to be highly reliable. This made possible the establishment of normative data 21
in a large sample of healthy athletes. 22
Keywords: patella; alignment; reliability; assessment. 23
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INTRODUCTION 25
Alterations of frontal plane patellar alignment (i.e. patellar rotation) 26
may contribute to development of clinical conditions, such as patellofemoral 27
pain syndrome and patellar tendinopathy (Powers, 2003; Mendonça, Macedo, 28
Silva & Fonseca, 2005; Wilson, 2009; Barton, Bonanno, Levinger & Menz, 29
2010; Draper et al., 2010; Lin et al., 2010; Powers, 2010; Souza et al., 2010). 30
The proposed contribution of patellar rotation to development of these 31
conditions is associated to changes in dynamic patellar alignment on the 32
femoral trochlear groove during knee flexion and extension (Draper et al., 33
2010; Lin et al., 2010; Souza et al., 2010; Wilson, Mazahery, Koh & Zhang, 34
2010), and to asymmetrical force distribution on the medial and lateral 35
retinaculum and on the medial and lateral portions of patellar tendon (Elvin et 36
al., 2009; Lin et al., 2010; Wen, 2007; Zachazewski, Magee & Quillen, 1996). 37
These asymmetries may result in overload to specific regions of the patella 38
and its tendon. Therefore, the presence of patella rotation may be considered a 39
factor that may contribute to the development or worsening of musculoskeletal 40
dysfunctions (Barton et al., 2010; Diederichs et al., 2013; Draper et al., 2010; 41
Powers, 2010; Reiman, Bolgla & Lorenz, 2009). 42
The classification of biomechanical factors as relevant or not depends 43
on the comparison with normative data. Although the literature describes 44
frontal plane changes in patellar alignment (Arno, 1990; Mendonça et al., 45
2005; Wilson et al., 2009; Zachazewski et al., 1996), there is no reported 46
normative data of this alignment to identify which values could be expected as 47
normal and those that could characterize the presence of excessive patellar 48
rotation. The existence of normative values for patellar rotation would allow 49
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clinicians to characterize the patellar alignment in a specific population to help 50
determining what could be considered clinically relevant. 51
Some measurements have been proposed to evaluate the frontal plane 52
patellar alignment (Diederichs et al., 2013; Draper et al., 2010; MacIntyre et 53
al., 2008). Magnetic resonance imaging and computed tomography, for 54
example, are exams that could be used as measurements of patellar rotation 55
(Diederichs et al., 2013; Draper et al., 2010; MacIntyre et al., 2008). If on one 56
hand, these exams allow a tridimensional analysis of patellar alignment, on the 57
other hand, they have low applicability in clinical context due to high costs 58
(Draper et al., 2010; Wilson, 2007) and to the non-functional information they 59
provide as a result of the patient positioning during examination (Diederichs et 60
al., 2013). Thus, in clinical settings, some methods involving visual estimation 61
and palpation have been proposed to evaluate the patellar alignment (Diveta & 62
Volgelbach, 1992; Zachazewski et al., 1996; Ehrat, 1994). However, these 63
methods have low reliability (Diveta & Volgelbach, 1992; Tomsich, Nitz, 64
Threlkeld & Shapiro, 1996; Wilson, 2007), preventing the establishment of 65
normative values. 66
In order to allow the quantification of frontal plane patellar alignment, 67
two clinically feasible methods have been proposed: McConnell and Arno 68
angles (Arno, 1990; Diveta & Volgelbach, 1992; Ehrat, 1994; Mendonça et 69
al., 2005; Watson et al., 1999). The former considers the patellar alignment 70
relative to the femur and the latter relative to the tibia. The first point to be 71
raised is that, since each angle considers the patellar alignment relative to 72
different references (segments), do they measure exactly the same aspect of 73
patellar alignment? The second point is relative to the patient positioning 74
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during the test. Traditionally, the patient position during the evaluation of both 75
angles is in relaxed supine lying. However, as distal (e.g. shank and foot) and 76
proximal body segments (e.g. hip and thigh) may influence patellar alignment 77
through retinaculum tensioning (Barton et al., 2010; Mendonça et al., 2005; 78
Reiman et al., 2009), the angles of patellar rotation obtained with traditional 79
positioning (supine with knee extension) may not represent the real patellar 80
position in functional situations. Therefore, the measurement of patellar 81
alignment has to consider a more functional position in order to take into 82
account these biomechanical influences. A position that considers the 83
influence of the tensioning of the patellar retinaculum is standing with semi 84
flexed knees (in a position around 30°) (Wilson et al., 2009; Draper et al., 85
2010; Souza et al., 2010). 86
The use of normative data in clinical practice, especially in sports, is 87
facilitated when the method chosen is fast and easily applied, in order to allow 88
the evaluation of a large number of individuals in a short period (e.g. athletes 89
preseason screening). In addition, standardization and adequate reliability of 90
the method is a precondition to the test to be used. Thus, the main purposes of 91
this study were (1) to generate normative data to characterize frontal plane 92
patellar alignment in athletes (2) verify the association between McConnell 93
and Arno angles, and (3) verify the distribution of the types of frontal plane 94
patellar alignments in different sports modalities. To achieve this aim, a 95
preliminary methodological study was carried out to evaluate the reliability of 96
the proposed standardized method to measure the McConnell and Arno angles. 97
98
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METHODS 100
Two studies were carried out in order to attain the objectives. First, a 101
methodological study was performed to develop a method to measure the 102
McConnell and Arno angles in standing position and to determine the inter 103
and intra examiners reliability. Second, the main study was carried out with a 104
larger number of athletes, in order to obtain normative data on frontal plane 105
patellar alignment. In both studies, the procedures to measure the patellar 106
alignment were the same. Participants with history of injuries or surgery in the 107
lower limbs extremity in the previous six months were not included in any of 108
the studies. Informed consent was obtained for all participants and the rights 109
of subjects were protected in both studies. 110
Reliability Study 111
Nine volunteers (18 knees) who practiced sports activities five times a 112
week took part in this study. The sample was comprised of 3 men and 6 113
women (mean age of 22.66 ± 2.54 years; mean height of 1.68 ± 0.79 m; and 114
mean body mass of 64.88 ± 8.32 kg). Two examiners assessed the 115
participants. In order to allow the intra-examiner reliability assessment, each 116
examiner measured the same participant twice with an interval of three days. 117
In the same evaluation session, the measures were done with 15-minute 118
intervals between examiners in order to avoid fatigue of the lower limb 119
muscles. The examiners could not access the results obtained by each other. A 120
third examiner removed all marks on the athlete’s skin (more details in 121
patellar alignment measurement description) during the interval between the 122
evaluations of each examiner to make sure that they could not see the marks 123
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made by each other. The second measurement of each examiner was used for 124
inter-examiner reliability analysis. 125
126
Normative Data Study 127
After the reliability investigation, the two examiners evaluated two 128
hundred and thirty athletes (460 knees) of different sports: volleyball (n= 68), 129
basketball (n= 50), gymnastics (n= 59) and soccer (n = 53). Demographic data 130
of each modality are presented in TABLE 1. 131
132
Insert TABLE 1 about here 133
134
Patellar alignment measurement 135
To evaluate the frontal plane patellar alignment, reflective markers 136
were attached bilaterally to the anterior superior iliac spine (ASIS), femoral 137
epicondyles, midpoint of the patellar base (determined with a measuring tape), 138
inferior pole (apex) of the patella and tibial tuberosity. The markers’ 139
placements and photographic records were determined with the subject in 140
bipedal standing with the knees flexed at 30o degrees (measured with universal 141
goniometer) (FIGURE 1). The knee was positioned in flexion to allow the 142
assessment of patellar alignment under the influence of patellar retinaculum 143
tensioning (Mendonça et al., 2005; Wilson et al., 2009; Draper et al., 2010; 144
Souza et al., 2010) and to avoid overestimation of Arno angle due to external 145
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rotation of the tibia due to knee extension. While maintaining this position, the 146
individual was asked to keep a wooden stick, placed over the shoulders, 147
aligned parallel to the wall and floor. This procedure was used to ensure 148
proper subject positioning without trunk rotation. Photographic records of the 149
subjects were performed with a digital camera (SC-D385, Samsung®) 150
positioned parallel to the ground and placed perpendicular to the frontal plane 151
of the athlete. The subjects were evaluated barefoot. 152
153
Insert FIGURE 1 about here 154
155
The McConnell and Arno angles were used to quantify frontal plane 156
patellar alignment. Initially, the midpoint between the femoral epicondyles, 157
the femoral bisection (line between the ASIS marker and midpoint between 158
femoral epicondyles), the patellar bisection (line between midpoint of the base 159
and inferior pole of the patella) and patellar tendon bisection (line between the 160
inferior pole of the patella and tibial tuberosity) were determined (FIGURES 2 161
and 3). The McConnell angle was defined as the angle between the femoral 162
bisection and patellar bisection (FIGURE 2). The Arno angle was defined as 163
the angle between the patellar bisection and patellar tendon bisection 164
(FIGURE 3) (Mendonça et al., 2005). The bisections and the calculation of the 165
angles (in degrees) were performed by an examiner who was not involved in 166
data collection using the software Simi Motion Twinner®. 167
168
Insert FIGURES 2 and 3 about here 169
170
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In addition to the mean angle calculated for both McConnell and Arno 171
measures, the patellar alignment was characterized relative the direction of 172
rotation. The anatomic reference used to this classification was the inferior 173
pole of the patella. Medial rotation of the patella was defined as present when 174
the inferior pole of the patella was pointed medially to the femoral bisection 175
(McConnell angle) or to the patellar tendon bisection (Arno angle) and 176
received negative values. When the inferior pole of the patella was pointed 177
laterally to the femoral or patellar tendon bisections, it was defined as lateral 178
rotation according to McConnell and Arno respectively. Lateral rotation 179
received positive values (Arno, 1990; Watson et al., 1999). Values between 180
+1o and -1o were classified as neutral patellar alignment in the frontal plane. 181
182
Statistical Analysis 183
In the reliability study, Intraclass correlation coefficients (ICC3,1) were 184
used to determine intra- and inter-examiners reliability. In addition, the 185
Standard Error of Measurement (SEM) of each measure was calculated. In the 186
Normative Data study, descriptive statistics were used to characterize the 187
patellar alignment in the frontal plane, considering both lower limbs (460 188
lower limbs). Pearson’s correlation was carried out to investigate the 189
association between McConnell and Arno angles. Chi-square tests (X2) were 190
used to verify the distribution of patellar rotation type, according each angle 191
measured, between the sports modality assessed in this study. The alpha level 192
for the analyses was set at 0.05. 193
194
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RESULTS 195
Reliability Study 196
The proposed method to measure the McConnell and Arno angles had 197
excellent intra and inter examiners reliabilities (ICC3,1 varied from 0.85 to 198
0.98). The SEM values varied from 0.08 to 0.33 degrees. The means, standard 199
deviations of the patellar alignment angles, reliability coefficients and SEM 200
are presented in TABLE 2. 201
202
Insert TABLE 2 about here 203
204
Normative Study 205
Descriptive data was obtained considering the magnitude of patellar 206
alignment and the classification of patellar alignment, with their respective 207
magnitude, according to McConnell and Arno angles measures. These values 208
are presented in TABLE 3. 209
Pearson’s correlation coefficient demonstrated low association 210
between McConnell and Arno angles (r = 0.189, p <0.0001), confirming that 211
they measure different dimensions of patellar alignment. However, differences 212
were found in type distribution between sports modalities for McConnell 213
angle (X2=15.99; p= .014). Post-hoc analysis showed that volleyball athletes 214
presented greater proportion of patellar medial rotation compared to gymnastic 215
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athletes (details on TABLE 3). Arno angle showed no difference in the type 216
distribution between sports modalities (X2=4.47; p= .613). 217
218
Insert TABLE 3 about here 219
220
221
222
223
224
225
226
227
228
229
230
231
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233
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DISCUSSION 235
The present study introduced the standardization of a method to 236
measure the McConnell and Arno angles in standing position with semi flexed 237
knee, using photogrammetry. The results demonstrated that this method had 238
excellent intra and inter reliability and low standard error of measurement. In 239
addition, this study allowed the characterization of the frontal plane patellar 240
alignment in 230 subjects (460 lower limbs) from different sports modalities. 241
The high reliability and practical applicability of this method indicates that the 242
clinical evaluation of McConnell and Arno angles can be inserted in 243
preseasons assessments involving a large number of athletes. In addition, the 244
obtained values in these evaluations can be compared with the normative data 245
provided by the presented study. This will make it possible to evaluate the 246
contribution of the frontal plane patellar alignment to the occurrence of 247
patellofemoral joint disorders. 248
The two-dimensional measurement method of patellar alignment had 249
excellent intra and inter-rater reliability (ICC ranging from 0.85 to 0.98), 250
despite of small sample size assessed in the methodological study. Studies that 251
investigate psychometric properties of patellar alignment measurements did 252
not show adequate reliability, especially inter-examiner (Diveta & Vogelbach, 253
1992; Tomsich et al., 1996). Diveta & Vogelbach (1992) reported inter-rater 254
reliability coefficients of ICC= -0.01 for Arno angle, measured with a 255
goniometer with the subject in supine position (Diveta & Vogelbach, 1992). 256
Tomsich et al (1996) measured patellar rotation with goniometer and also 257
showed low intra and inter-examiner coefficients for McConnell (ICC 258
intra=0.52 and ICC inter=0.003) and Arno angles (ICC intra=0.61 and ICC 259
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inter=0.49) (Tomsich et al., 1996). As the authors argued, factors such as lack 260
of examiners experience, little time devoted to training the measures and 261
restricted time for the examiner to define the patellar alignment may explain 262
the low reliability observed in these studies (Diveta & Vogelbach, 1992; 263
Tomsich et al., 1996). On the other hand, the standardized method and the 264
image analysis proposed in the present study achieved high reliability. In 265
addition to the high reliability, the method used in the present study had low 266
measurement error. The SEM values varied from 0.06o to 0.33o and from 0.08o 267
to 0.29o, respectively for Arno and McConnell angles. The SEM values 268
obtained in the present study indicate an expected spread around a given result 269
of less than one degree, which reinforces the appropriateness of this 270
standardized measure. 271
The measurements used in the present study involved palpation of 272
anatomic landmarks for reflective markers placement as others methods 273
reported in literature (Diveta & Vogelbach, 1992; Tomsich et al., 1996; 274
Mendonça et al., 2005). Therefore, the high reliability depends on palpation 275
training of these landmarks in order to the evaluator to become more accurate 276
and reliable. Palpation performed with the individual in standing seems to 277
have the potential to reduce errors of placing anatomical marks by the 278
examiner. In this position, the patella is more stable by muscular action and 279
patellar retinaculum tensioning, due to the knee flexion, which also highlights 280
the patella contours. In addition, some procedures were established in the 281
present study to prevent anatomical variations to hamper patellar palpation 282
and the correct identification of markers’ location. For example, to identify the 283
inferior pole of the patella, it was defined that, for those individuals with 284
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enlarged fat pads, the examiner should produce a slight superior tilt of the 285
patella, aiming to define the inferior pole contours to facilitate the 286
identification of its location for marker placement. Similarly, for the anterior 287
tibial tuberosity, it was established that the highest tuberosity’s prominence 288
should be used as reference. However, for those individuals with a flat 289
superior tibial portion, the tuberosity midpoint was defined as reference for the 290
marker placement. This standardization for location of anatomic references, 291
certainly, contributed to the excellent reliability and low measurement error 292
observed in the present study and it could be used in future studies 293
implemented to assess patellar alignment. 294
The study performed in 230 healthy athletes allowed the 295
characterization of the frontal plane patellar alignment. This large number of 296
lower limb assessed (n = 460 knees) allows the obtained values of patellar 297
alignment to be used as normative data. The mean values of patellar alignment 298
for the total sample of the study were 2.05o for McConnell and 2.98o for Arno 299
angle. Although there are no reports of normative values for these angles, it is 300
possible to compare our results with mean values reported by some reliability 301
studies. Diveta & Vogelbach (1992) found 12.3o (± 3.4o) for Arno angle in 15 302
healthy subjects. Mendonça et al. (2005) reported a mean of 7.06o (± 6.4o) for 303
McConnell and 9.1o (± 7.1o) for Arno angle in 14 healthy individuals. The 304
discrepancy of the values obtained in the present study and the values obtained 305
by Diveta & Vogelbach (1992) and Mendonça et al. (2005) can be due to 306
differences in the participant’s positioning during the test. This test positioning 307
applies more specifically to the Arno angle. Since the Arno angle considers 308
the patellar alignment relative to the tibial tuberosity, the tibial position can 309
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influence the magnitude of this angle. In supine position with knee extension, 310
the tibia is externally rotated relative the femur (knee locking mechanism), 311
which could cause an increase of the Arno angle (Zachazewski et al., 1996). In 312
the present study, as the participant was standing with the knee semi flexed 313
(30o), the tibia was not externally rotated, which could explain the smaller 314
values of the patellar alignment according to Arno angle. Another important 315
point to be stressed is that the values obtained in the studies of Diveta & 316
Vogelbach (1992) and Mendonça et al. (2005) were obtained in a small 317
sample. In addition, it should be taken into account the low reliability 318
observed by the former (ICC= -0.01) and high standard error of measurement 319
observed by the latter (SEM = 6,4º and 7,0º). 320
The present study showed significant but low association (r = 0.189) 321
between McConnell and Arno angles obtained from the 460 lower limbs 322
assessed. This result indicates that although both angles have been proposed to 323
measure patellar alignment in the frontal plane, they are, probably, measuring 324
different aspects of this alignment. In one hand, the McConnell angle may 325
inform about the influence of the patellar retinaculum on the patellar 326
positioning in relation to the femur. In this case, the patella alignment reflects 327
the stiffness distribution between medial and lateral portions of retinaculum 328
and the distribution of the resultant forces on the trochlea and patellar facets. 329
On the other hand, the Arno angle may inform about the distribution of forces 330
acting on the medial and lateral tissues related to the patellar tendon 331
(Diederichs et al., 2013). In this case, it may also inform about the overload on 332
the patellar tendon. Since each angle informs about different dimensions of the 333
patellar alignment, which might lead to different consequences of possible 334
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misalignments, both angles should be incorporated in the investigation of the 335
frontal plane patellar alignment. 336
The data showed that lateral patellar rotation was more frequent than 337
medial rotation in both angles measured. However, there was a difference in 338
the distribution of patellar rotation type across sports modalities only for the 339
McConnell angle (p= .014). Post-hoc analysis identified that volleyball players 340
had proportionally more patellar medial rotation than gymnasts (51 and 23, 341
respectively). These results suggest that the pattern of motion adopted by 342
volleyball athletes may contribute to the medially rotated patellar posture. 343
Probably, landings in volleyball involve more latero-medial forces and the 344
iliotibial band in these athletes could be more tensioned compared to 345
gymnastics athletes. Medial rotation of the patella is associated to tension on 346
iliotibial band (Merican & Amis, 2009). Therefore, retinacular tension 347
distribution may differ between these sports modalities, producing distinct 348
distribution of patellar medial rotation. 349
A limitation of the proposed method in clinical settings is the necessity 350
of data processing after athlete’s assessment to quantify the angles. 351
Specifically, it is necessary to construct a midpoint between the reflective 352
markers placed in femoral condyles in order to define femur bisection needed 353
to determine McConnell angle. Possibly, commercial photographic analysis 354
software could be not financially and logistically accessible to all examiners. 355
Future studies could investigate the correlation of the procedure used to define 356
femur bisection and those with free software or manual identification of 357
condyles midpoint by metric tape. 358
The present study established unprecedented normative values relative 359
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to fontal plane patellar alignment and the presence of patellar rotation in 360
young asymptomatic athletes. The next step would be the assessment of the 361
patellar alignment in individuals with clinical conditions as patelofemoral pain 362
and patellar tendinopathy using the same method proposed in this study. This 363
investigation would allow verifying whether patellar misalignment is present 364
or associated to these clinical conditions and, more specifically, what 365
magnitude of patellar rotation can be considered clinically relevant to 366
development of these conditions. 367
368
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CONCLUSION 385
The present study proposed a standardized method for measuring the 386
patellar alignment in the frontal plane using photogrammetry. This method 387
that allow the quantification of the McConnell and Arno angles had excellent 388
reliability and low standard error of measurement. This study provided 389
reference data of patellar alignment and identified presence of patellar rotation 390
in healthy athletes of different sports modalities. In addition, it was observed a 391
weak association between the McConnell and Arno angles, which suggest that 392
these angles capture different aspects of frontal plane patellar alignment. 393
394
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Ethical Approval: The protocol for this study was approved by The Ethics in 410
Research Committee of the Universidade Federal de Minas Gerais (Approval 411
Report number 0493.0.203.000-09). 412
Funding: This study was partially funded by the Brazilian agencies Conselho 413
Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and Fundação 414
de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG). 415
Conflict of Interest: All authors have no conflict of interest to declare. 416
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REFERENCES 432
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ankle characteristics in patellofemoral pain syndrome: a case control and 436
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& Scheffler, S. (2013). Magnetic resonance imaging analysis of rotational 440
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Ehrat, M. (1994). Reliability of assessing patellar alignment: the A angle. 450
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Lin, F., Wilson, N. A., Makhsous, M., Press, J. M., Koh, J. L., Nuber, G. W., 455
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quadriceps components in individuals with patellofemoral pain. Journal of 457
biomechanics. 43 (2), 235-241. 458
MacIntyre, N. J., McKnight, E. K. B., Day, A., & Wilson, D. R. (2008). 459
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Merican, A. M., & Amis, A. A. (2009). Iliotibial band tension affects 467
patellofemoral and tibiofemoral kinematics. Journal of Biomechanics, 42, 468
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resonance imaging analysis. Journal of orthopaedic and sports physical 481
therapy, 40 (5), 277-285. 482
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physical therapy, 23 (3), 200-208. 485
Watson, C., Propps, M., Galt, W., Redding, A., & Dobbs, D. (1999). 486
Reliability of McConnell's classification of patellar orientation in 487
symptomatic and asymptomatic subjects. Journal of orthopaedic and sports 488
physical therapy, 29 (7), 378-393. 489
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bracing on dynamic patellofemoral contact mechanics. Journal of 493
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In Vivo noninvasive evaluation of abnormal patellar tracking during squatting 496
in patients with patellofemoral pain. Journal of bone and joint surgery, 91, 497
558-566. 498
Wilson, T. (2007). The measurement of patellar alignment in patellofemoral 499
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504
505
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TABLES 506
507
TABLE 1: Demographic data for volleyball, basketball, gymnastics and soccer 508
athletes 509
Female/Male* Age (years) † Body mass (kg) † Height (cm) †
Volleyball 27/41 18.27 (6.73) 71.13 (17.04) 179.15 (14.35)
Basketball 0/50 14.46 (2.38) 66.94 (18.68) 176.85 (16.91)
Gymnastics 17/42 13.91 (3.53) 55.67 (18.34) 165.94 (23.03)
Soccer 24/29 17.09 (3.36) 59.94 (10.23) 168.59 (7.46)
kg = kilograms, cm = centimeters. 510
*. values indicate the frequency of each patellar alignment classification 511
†. values indicate mean (standard deviation) 512
513
514
515
516
517
518
519
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TABLE 2: Means (standard deviations – SD) of the patellar alignment 520
magnitude (in degrees), according to McConnell and Arno, reliability 521
coefficients (Intraclass Correlation Coefficient – ICC) and standard error of 522
measurement in degrees (SEM) from both measures of patellar alignment 523
obtained by the Examiners E1 ad E2 in the moments of measures 1 and 2. 524
Examiners: E1 and
E2; moment of
measure (1) and (2)
McConnell Angle Arno Angle
Mean (SD)
Intra
E1 (1)
E1(2)
E2 (1)
E2 (2)
1.53 (5.37)
1.27 (4.93)
1.15 (3.75)
.01 (3.64)
2.96 (9.76)
5.90 (8.52)
6.25 (7.39)
7.10 (3.45)
Inter
E1 (2)
E2 (2)
3.33 (2.60)
.50 (4.09)
12.94 (7.19)
10.09 (4.25)
ICC (SEM)
Intra
E1(1) x E1(2)
E2(1) x E2(2)
Inter
.97 (.08)
.92 (.17)
.95 (.26)
.98 (.06)
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E1 x E2 .85 (0,29) .90 (0,33)
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
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TABLE 3: Normative data for McConnell and Arno angles obtained from 460 542
lower limbs. The magnitude (in means and standard deviation) and the type of 543
patellar rotation are presented for each sports modality and for the total 544
sample. 545
Total Sample Volleyball Basketball Gymnastics Soccer
McConnell Angle
Mean (SD) 2.05 (5.09) 1.55 (5.68) 2.00 (4.90) 3.19 (5.06) 1.46 (4.32)
Minimum -13.80 -10.38 -10.90 -13.80 -12.28
Maximum 19.68 19.68 16.98 13.38 15.11
Medial Rotation*
125
-4.05(2.66)
51a
-4.10(2.43)
26a,b
-3.73(2.41)
23b
-4.14(3.49)
25a,b
-4.21(2.62)
Lateral Rotation*
273
5.34 (3.38)
73a
5.83 (3.82)
56a
5.42(3.35)
81a
5.85(3.07)
63a
4.04(2.95)
Neutral Rotation*
62
-.13 (.63)
12a
-.40 (.50)
18a
-.36(.59)
14a
-.18(.52)
18a
.30(.62)
Arno Angle
Mean (SD) 2.89 (7.57) 2.90 (8.86) 1.94 (6.68) 4.25 (7.61) 2.24 (6.32)
Minimum -19.94 -19.94 -14.34 -12.16 -13.13
Maximum 24.34 24.34 17.68 22.17 17.43
Medial Rotation*
121
-6.47 (4.09)
38
-8.47(4.73)
27
-5.73(4.15)
27
-5.37(2.79)
29
-5.57(3.20)
Lateral Rotation*
284
7.40 (5.19)
87
8.17(5.26)
57
6.09(4.89)
76
8.53(5.63)
64
6.14(4.23)
Neutral Rotation*
55
.28 (.43)
11
.49(.34)
16
.09(.45)
14
.11(.42)
13
.52(.29)
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* The values indicate the frequency of individuals in each category of patellar 546
alignment followed by the mean (standard deviation), in degrees. 547
Each subscript letter denotes a subset of modalities categories whose column 548
proportions do not differ significantly from each other at the .05 level for the 549
post-hoc of X2 test. 550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
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FIGURES 565
566
FIGURE 1: Subject’s position for photographic record 567
568
FIGURE 2: Building of femur (solid line) and patella (dotted line) bisections 569
to determine McConnell angle. 570
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571
FIGURE 3: Building of patellar tendon (solid line) and patella (dotted line) 572
bisections to determine Arno angle. 573
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Acknowledgements
We thank the physiotherapist of SADA-Cruzeiro volleyball team (Betim -
Brazil), Alysson Zuin, for the partnership with our research group and to help in this
study. We appreciate Minas Tênis Clube’s Health Manager, Deborah Rocha da Costa
Reis, support for this study and the Núcleo de Integração de Ciências do Esporte
(Minas Tênis Clube, Brazil) for help with logistics during data collection.
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Highlights:
• We develop a clinical method of assessing frontal plane patellar alignment.
• This method presented an excellent intra and inter-examiner reliability
• Normative data are presented and could guide assessment and rehabilitation.
• This method and can be incorporated to athletes' pre-season assessment.