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Inter and intra-observer reliability in assessment of the position of the lateral sesamoid in determining the severity of hallux valgus
G Model
ARTICLE IN PRESS
YFOOT-1410; No. of Pages 3
The Foot xxx (2015) xxx–xxx
Contents lists available at ScienceDirect
The Foot journal homepage: www.elsevier.com/locate/foot
Inter and intra-observer reliability in assessment of the position of the lateral sesamoid in determining the severity of hallux valgus Sunil Panchani ∗ , Jonathan Reading, Jaysheel Mehta Rochdale Infirmary, Whitehall Street, Rochdale OL12 0NB, Lancashire, United Kingdom
h i g h l i g h t s • • • •
The position of the lateral sesamoid correlates well in previous studies with the severity of hallux valgus. We performed an intra and inter observer reliability study on this classification system. Kappa values were high amongst consultant and registrar observers. The lateral sesamoid classification system shows good intra and inter observer reliability.
a r t i c l e
i n f o
Article history: Received 12 February 2015 Received in revised form 14 September 2015 Accepted 5 October 2015 Keywords: Hallux valgus Sesamoid Foot surgery Classification
a b s t r a c t Background: The position of the lateral sesamoid on standard dorso-plantar weight bearing radiographs, with respect to the lateral cortex of the first metatarsal, has been shown to correlate well with the degree of the hallux valgus angle. This study aimed to assess the inter- and intra-observer error of this new classification system. Methods: Five orthopaedic consultants and five trainee orthopaedic surgeons were recruited to assess and document the degree of displacement of the lateral sesamoid on 144 weight-bearing dorso-plantar radiographs on two separate occasions. The severity of hallux valgus was defined as normal (0%), mild (≤50%), moderate (51–≤99%) or severe (≥100%) depending on the percentage displacement of the lateral sesamoid body from the lateral cortical border of the first metatarsal. Results: Consultant intra-observer variability showed good agreement between repeated assessment of the radiographs (mean Kappa = 0.75). Intra-observer variability for trainee orthopaedic surgeons also showed good agreement with a mean Kappa = 0.73. Intraclass correlations for consultants and trainee surgeons was also high. Conclusion: The new classification system of assessing the severity of hallux valgus shows high inter- and intra-observer variability with good agreement and reproducibility between surgeons of consultant and trainee grades. © 2015 Elsevier Ltd. All rights reserved.
1. Introduction The evaluation of the severity of a hallux valgus deformity is important in not only classifying the condition but also in guiding the management of the condition itself [1]. Various classification systems rely on the assessment of radiographic angles based upon dorso-plantar radiographs. These include the assessment of the hallux valgus angle, the hallux valgus interphalangeus angle, the
∗ Corresponding author. Tel.: +44 7979398891. E-mail addresses: [email protected] (S. Panchani), jonathan [email protected] (J. Reading), [email protected] (J. Mehta).
inter-metatarsal angle between the first and the second ray and the distal metatarsal articular angle [1]. The position of the lateral sesamoid in relation to the lateral border of the first metatarsal has been proposed as a useful indicator of the severity of the hallux valgus deformity and Agrawal et al. showed this position to significantly correlate with the severity of the intermetatarsal angle and the hallux valgus angle [2]. The authors of the study recommended its use in assessing the severity of the deformity and thus guiding management. The classification system by Agrawal et al. categorised the severity of the hallux valgus deformity into normal, mild, moderate and severe depending on the percentage displacement of the lateral sesamoid from the cortical margin of the first ray.
http://dx.doi.org/10.1016/j.foot.2015.10.001 0958-2592/© 2015 Elsevier Ltd. All rights reserved.
Please cite this article in press as: Panchani S, et al. Inter and intra-observer reliability in assessment of the position of the lateral sesamoid in determining the severity of hallux valgus. Foot (2015), http://dx.doi.org/10.1016/j.foot.2015.10.001
G Model YFOOT-1410; No. of Pages 3
ARTICLE IN PRESS S. Panchani et al. / The Foot xxx (2015) xxx–xxx
2
Fig. 1. Lateral sesamoid position classification [2].
Studies have previously shown excellent inter and intraobserver reliability in measuring the intermetatarsal angle and the hallux valgus angle [3,4]. The aim of this study was to assess the intra and inter-observer reliability of assessing the position of the lateral sesamoid on standard dorso-plantar radiographs.
standard departmental protocols with the centre of the beam aimed at the third metatarsal. All radiographs were viewed using the Centricity® Web v3.0 digital viewing system and data was analysed using the statistical package SPSS v19.0. Intra-class correlation coefficients were calculated to assess inter-observer reliability and Kappa values were calculated to assess intra-observer reliability.
2. Methods 3. Results Five Consultant Orthopaedic Surgeons, who had not specialised in Foot and Ankle surgery, and five trainee orthopaedic surgeons were recruited to participate in the study. Each subject was briefed on the study protocol and the lateral sesamoid classification system. The classification system is depicted in Fig. 1. Each subject was asked to classify the severity of the hallux valgus deformity on 144 dorso-plantar radiographs according to the position of the lateral sesamoid and the observations were repeated after a 4 week interval. The severity of hallux valgus was defined as normal (0%), mild (≤ 50%), moderate (51–≤99%) or severe (≥100%) depending on the percentage displacement of the lateral sesamoid body from the lateral cortical border of the first metatarsal. A total of 144 consecutive dorso-plantar weight bearing radiographs were included in the study. Radiographs were taken with
A complete data set was obtained for all subjects for all radiographs included in the study. Intraclass correlations (ICC) for consultants and trainee surgeons were high. This is the agreement between subjects in each of the two grades of surgeons who agreed that a particular radiograph was a certain classification i.e. normal, mild, moderate or severe. Consultant grade ICC values for the first and second observations were 0.82 (95% CI 0.75–0.87) and 0.86 (95% CI 0.80–0.90), respectively. Trainee grade ICC values for first and second observations were also high at 0.78 (95% CI 0.70–0.84) and 0.79 (95% CI 0.73–0.85), respectively (Table 1). Consultant mean Kappa value for intra-observer variability was 0.75 (range 0.53–0.84) and for trainee grade observer was 0.73
Please cite this article in press as: Panchani S, et al. Inter and intra-observer reliability in assessment of the position of the lateral sesamoid in determining the severity of hallux valgus. Foot (2015), http://dx.doi.org/10.1016/j.foot.2015.10.001
G Model YFOOT-1410; No. of Pages 3
ARTICLE IN PRESS S. Panchani et al. / The Foot xxx (2015) xxx–xxx
Table 1 Intraclass correlation co-efficient (ICC) value for consultant and trainee.
1st Reading 2nd Reading
Consultant
Trainee
0.82 (95% CI 0.75–0.87) 0.86 (95% CI 0.80–0.90)
0.78 (95% CI 0.70–0.84) 0.79 (95% CI 0.73–0.85)
(range 0.55–0.84) indicating good agreement between repeated assessments of radiographs. When reviewing the radiographs at observation 1 and 2, all five consultant subjects agreed that a particular radiograph was a particular severity of deformity 48% and 54% of the radiographs, respectively. When reviewing the radiographs at observation 1 and 2, all five trainee subjects agreed that a particular radiograph was a particular severity of deformity 45% and 48% of the radiographs, respectively. 4. Discussion Multiple radiographic assessment tools have been utilised in assessing the severity of hallux valgus deformity. These include the hallux valgus angle, inter-metatarsal angle and the distal metatarsal articular angles. Bryant et al. [5] reported ICC values of 0.96 and 0.91 when assessing the hallux valgus angle and intermetatarsal angle, respectively. Lee et al. [6] reported ICC values of 0.985 for measuring the hallux valgus angle, 0.896 for measuring the inter-metatarsal angle but a low ICC of 0.38 for the distal metatarsal articular angle. Saro et al. [7] reported ICC of 0.97 for assessment of hallux valgus angle. The lateral sesamoid position has been extensively studied in terms of its association with the severity of hallux valgus. As the severity of a hallux valgus deformity progresses, the first metatarsal drifts medially from its anchorage to the medial and lateral sesamoids [8]. The medial migration of the first metatarsal exposes the lateral sesamoid on a dorso-plantar radiograph whereas the projection of the medial sesamoid remains predominantly under the body of the first metatarsal. This is likely to hinder visualisation of the medial sesamoid. Various lateral sesamoid parameters have previously been advocated in assessment of hallux valgus severity. Sanhudo et al. [9] evaluated the linear distance between the lateral cortical margin of the first metatarsal to the lateral cortex of the lateral sesamoid and found high reproducibility and reliability when considering distances of 2 mm or more as significant. The sesamoid rotational angle (SRA) as measured by a tangential radiograph has also been proposed as a useful tool in assessing the sesamoid position [10] however the accuracy of this method has been shown to differ with varying ranges of metatarsophalangeal joint angles [11]. Lee et al. found the SRA to have an inter observer reliability ICC value of 0.925 [6].
3
Agrawal et al. found the position of the lateral sesamoid to correlate well with the hallux valgus (p < 0.0001) and the intermetatarsal angle (p < 0.0001) [2]. This study adds to the validity and reliability in assessing the position of the lateral sesamoid as a marker for the severity of a hallux valgus angle. Furthermore, the inter and intra-observer reliability was similar between the grades of subjects which shows this classification system is a reliable tool and its accuracy does not depend on surgical experience or grade of surgeon. Certainly, the classification as described by Agrawal et al. is a much simpler method of assessing the severity of a hallux valgus deformity as compared to measuring angles and it also allows a much more rapid assessment. Taking into account the ease of application of the classification system and ICC values of >0.70, the lateral sesamoid position is a useful and reliable tool in assessment of the severity of a hallux valgus deformity and the authors of this study recommend it’s use in clinical practice.
Acknowledgement We acknowledge Dr Julie Morris, Head of Medical Statistics, University Hospitals of South Manchester, for help with statistical analysis. References [1] Robinson AHN, Limbers JP. Modern concepts in the treatment of hallux valgus. J Bone Joint Surg 2005;87-B:1038–45. [2] Agrawal Y, Desai A, Mehta J. Lateral sesamoid position in hallux valgus: correlation with the conventional radiological assessment. Foot Ankle Surg 2011;17(Dec (4)):308–11. [3] Coughlin MJ, Freund E. The reliability of angular measurements in hallux valgus deformities. Foot Ankle Int 2001;22:369–79. [4] Saltzman C, Brandser E, Berbaum K, DeGnore L, Holmes J, Katcherian D, et al. Reliability of standard foot radiographic measurements. Foot Ankle Int 1994;15:661–5. [5] Bryant A, Tinley P, Singer K. A comparison of radiographic measurements in normal, hallux valgus, and hallux limitus feet. J Foot Ankle Surg 2000;39(Jan–Feb (1)):39–43. [6] Lee KM, Ahn S, Chung CY, Sung KH, Park MS. Reliability and Relationship of radiographic measurements in hallux valgus. Clin Orthop Relat Res 2012;470(9):2613–21. [7] Saro C, Johnson DN, Martinez De Aragón J, Lindgren U, Felländer-Tsai L. Reliability of radiological and cosmetic measurements in hallux valgus. Acta Radiol 2005;46(Dec (8)):843–51. [8] Mann RA, Coughlin MJ. Hallux valgus—etiology, anatomy, treatment and surgical considerations. Clin Orthop Relat Res 1981;157:31–41. [9] Sanhudo JV, Gomes JE, Rabello MC, Delucca G. Interobserver and intraobserver reproducibility of hallux valgus angular measurements and the study of a linear measurement. Foot Ankle Spec 2012;5(Dec (6)):374–7. [10] Kuwano T, Nagamine R, Sakaki K, Urabe K, Iwamoto Y. New radiographic analysis of sesamoid rotation in hallux valgus: comparison with conventional evaluation methods. Foot Ankle Int 2002;23(9):811–7. [11] Yildrim Y, Abukoglu C, Erol B, Esemenlli T. Effect of metatarsophalangeal position on the reliability of the tangential sesamoid view in determining sesamoid position. Foot Ankle Int 2005;26:247–50.
Please cite this article in press as: Panchani S, et al. Inter and intra-observer reliability in assessment of the position of the lateral sesamoid in determining the severity of hallux valgus. Foot (2015), http://dx.doi.org/10.1016/j.foot.2015.10.001
ARTICLE IN PRESS
YFOOT-1410; No. of Pages 3
The Foot xxx (2015) xxx–xxx
Contents lists available at ScienceDirect
The Foot journal homepage: www.elsevier.com/locate/foot
Inter and intra-observer reliability in assessment of the position of the lateral sesamoid in determining the severity of hallux valgus Sunil Panchani ∗ , Jonathan Reading, Jaysheel Mehta Rochdale Infirmary, Whitehall Street, Rochdale OL12 0NB, Lancashire, United Kingdom
h i g h l i g h t s • • • •
The position of the lateral sesamoid correlates well in previous studies with the severity of hallux valgus. We performed an intra and inter observer reliability study on this classification system. Kappa values were high amongst consultant and registrar observers. The lateral sesamoid classification system shows good intra and inter observer reliability.
a r t i c l e
i n f o
Article history: Received 12 February 2015 Received in revised form 14 September 2015 Accepted 5 October 2015 Keywords: Hallux valgus Sesamoid Foot surgery Classification
a b s t r a c t Background: The position of the lateral sesamoid on standard dorso-plantar weight bearing radiographs, with respect to the lateral cortex of the first metatarsal, has been shown to correlate well with the degree of the hallux valgus angle. This study aimed to assess the inter- and intra-observer error of this new classification system. Methods: Five orthopaedic consultants and five trainee orthopaedic surgeons were recruited to assess and document the degree of displacement of the lateral sesamoid on 144 weight-bearing dorso-plantar radiographs on two separate occasions. The severity of hallux valgus was defined as normal (0%), mild (≤50%), moderate (51–≤99%) or severe (≥100%) depending on the percentage displacement of the lateral sesamoid body from the lateral cortical border of the first metatarsal. Results: Consultant intra-observer variability showed good agreement between repeated assessment of the radiographs (mean Kappa = 0.75). Intra-observer variability for trainee orthopaedic surgeons also showed good agreement with a mean Kappa = 0.73. Intraclass correlations for consultants and trainee surgeons was also high. Conclusion: The new classification system of assessing the severity of hallux valgus shows high inter- and intra-observer variability with good agreement and reproducibility between surgeons of consultant and trainee grades. © 2015 Elsevier Ltd. All rights reserved.
1. Introduction The evaluation of the severity of a hallux valgus deformity is important in not only classifying the condition but also in guiding the management of the condition itself [1]. Various classification systems rely on the assessment of radiographic angles based upon dorso-plantar radiographs. These include the assessment of the hallux valgus angle, the hallux valgus interphalangeus angle, the
∗ Corresponding author. Tel.: +44 7979398891. E-mail addresses: [email protected] (S. Panchani), jonathan [email protected] (J. Reading), [email protected] (J. Mehta).
inter-metatarsal angle between the first and the second ray and the distal metatarsal articular angle [1]. The position of the lateral sesamoid in relation to the lateral border of the first metatarsal has been proposed as a useful indicator of the severity of the hallux valgus deformity and Agrawal et al. showed this position to significantly correlate with the severity of the intermetatarsal angle and the hallux valgus angle [2]. The authors of the study recommended its use in assessing the severity of the deformity and thus guiding management. The classification system by Agrawal et al. categorised the severity of the hallux valgus deformity into normal, mild, moderate and severe depending on the percentage displacement of the lateral sesamoid from the cortical margin of the first ray.
http://dx.doi.org/10.1016/j.foot.2015.10.001 0958-2592/© 2015 Elsevier Ltd. All rights reserved.
Please cite this article in press as: Panchani S, et al. Inter and intra-observer reliability in assessment of the position of the lateral sesamoid in determining the severity of hallux valgus. Foot (2015), http://dx.doi.org/10.1016/j.foot.2015.10.001
G Model YFOOT-1410; No. of Pages 3
ARTICLE IN PRESS S. Panchani et al. / The Foot xxx (2015) xxx–xxx
2
Fig. 1. Lateral sesamoid position classification [2].
Studies have previously shown excellent inter and intraobserver reliability in measuring the intermetatarsal angle and the hallux valgus angle [3,4]. The aim of this study was to assess the intra and inter-observer reliability of assessing the position of the lateral sesamoid on standard dorso-plantar radiographs.
standard departmental protocols with the centre of the beam aimed at the third metatarsal. All radiographs were viewed using the Centricity® Web v3.0 digital viewing system and data was analysed using the statistical package SPSS v19.0. Intra-class correlation coefficients were calculated to assess inter-observer reliability and Kappa values were calculated to assess intra-observer reliability.
2. Methods 3. Results Five Consultant Orthopaedic Surgeons, who had not specialised in Foot and Ankle surgery, and five trainee orthopaedic surgeons were recruited to participate in the study. Each subject was briefed on the study protocol and the lateral sesamoid classification system. The classification system is depicted in Fig. 1. Each subject was asked to classify the severity of the hallux valgus deformity on 144 dorso-plantar radiographs according to the position of the lateral sesamoid and the observations were repeated after a 4 week interval. The severity of hallux valgus was defined as normal (0%), mild (≤ 50%), moderate (51–≤99%) or severe (≥100%) depending on the percentage displacement of the lateral sesamoid body from the lateral cortical border of the first metatarsal. A total of 144 consecutive dorso-plantar weight bearing radiographs were included in the study. Radiographs were taken with
A complete data set was obtained for all subjects for all radiographs included in the study. Intraclass correlations (ICC) for consultants and trainee surgeons were high. This is the agreement between subjects in each of the two grades of surgeons who agreed that a particular radiograph was a certain classification i.e. normal, mild, moderate or severe. Consultant grade ICC values for the first and second observations were 0.82 (95% CI 0.75–0.87) and 0.86 (95% CI 0.80–0.90), respectively. Trainee grade ICC values for first and second observations were also high at 0.78 (95% CI 0.70–0.84) and 0.79 (95% CI 0.73–0.85), respectively (Table 1). Consultant mean Kappa value for intra-observer variability was 0.75 (range 0.53–0.84) and for trainee grade observer was 0.73
Please cite this article in press as: Panchani S, et al. Inter and intra-observer reliability in assessment of the position of the lateral sesamoid in determining the severity of hallux valgus. Foot (2015), http://dx.doi.org/10.1016/j.foot.2015.10.001
G Model YFOOT-1410; No. of Pages 3
ARTICLE IN PRESS S. Panchani et al. / The Foot xxx (2015) xxx–xxx
Table 1 Intraclass correlation co-efficient (ICC) value for consultant and trainee.
1st Reading 2nd Reading
Consultant
Trainee
0.82 (95% CI 0.75–0.87) 0.86 (95% CI 0.80–0.90)
0.78 (95% CI 0.70–0.84) 0.79 (95% CI 0.73–0.85)
(range 0.55–0.84) indicating good agreement between repeated assessments of radiographs. When reviewing the radiographs at observation 1 and 2, all five consultant subjects agreed that a particular radiograph was a particular severity of deformity 48% and 54% of the radiographs, respectively. When reviewing the radiographs at observation 1 and 2, all five trainee subjects agreed that a particular radiograph was a particular severity of deformity 45% and 48% of the radiographs, respectively. 4. Discussion Multiple radiographic assessment tools have been utilised in assessing the severity of hallux valgus deformity. These include the hallux valgus angle, inter-metatarsal angle and the distal metatarsal articular angles. Bryant et al. [5] reported ICC values of 0.96 and 0.91 when assessing the hallux valgus angle and intermetatarsal angle, respectively. Lee et al. [6] reported ICC values of 0.985 for measuring the hallux valgus angle, 0.896 for measuring the inter-metatarsal angle but a low ICC of 0.38 for the distal metatarsal articular angle. Saro et al. [7] reported ICC of 0.97 for assessment of hallux valgus angle. The lateral sesamoid position has been extensively studied in terms of its association with the severity of hallux valgus. As the severity of a hallux valgus deformity progresses, the first metatarsal drifts medially from its anchorage to the medial and lateral sesamoids [8]. The medial migration of the first metatarsal exposes the lateral sesamoid on a dorso-plantar radiograph whereas the projection of the medial sesamoid remains predominantly under the body of the first metatarsal. This is likely to hinder visualisation of the medial sesamoid. Various lateral sesamoid parameters have previously been advocated in assessment of hallux valgus severity. Sanhudo et al. [9] evaluated the linear distance between the lateral cortical margin of the first metatarsal to the lateral cortex of the lateral sesamoid and found high reproducibility and reliability when considering distances of 2 mm or more as significant. The sesamoid rotational angle (SRA) as measured by a tangential radiograph has also been proposed as a useful tool in assessing the sesamoid position [10] however the accuracy of this method has been shown to differ with varying ranges of metatarsophalangeal joint angles [11]. Lee et al. found the SRA to have an inter observer reliability ICC value of 0.925 [6].
3
Agrawal et al. found the position of the lateral sesamoid to correlate well with the hallux valgus (p < 0.0001) and the intermetatarsal angle (p < 0.0001) [2]. This study adds to the validity and reliability in assessing the position of the lateral sesamoid as a marker for the severity of a hallux valgus angle. Furthermore, the inter and intra-observer reliability was similar between the grades of subjects which shows this classification system is a reliable tool and its accuracy does not depend on surgical experience or grade of surgeon. Certainly, the classification as described by Agrawal et al. is a much simpler method of assessing the severity of a hallux valgus deformity as compared to measuring angles and it also allows a much more rapid assessment. Taking into account the ease of application of the classification system and ICC values of >0.70, the lateral sesamoid position is a useful and reliable tool in assessment of the severity of a hallux valgus deformity and the authors of this study recommend it’s use in clinical practice.
Acknowledgement We acknowledge Dr Julie Morris, Head of Medical Statistics, University Hospitals of South Manchester, for help with statistical analysis. References [1] Robinson AHN, Limbers JP. Modern concepts in the treatment of hallux valgus. J Bone Joint Surg 2005;87-B:1038–45. [2] Agrawal Y, Desai A, Mehta J. Lateral sesamoid position in hallux valgus: correlation with the conventional radiological assessment. Foot Ankle Surg 2011;17(Dec (4)):308–11. [3] Coughlin MJ, Freund E. The reliability of angular measurements in hallux valgus deformities. Foot Ankle Int 2001;22:369–79. [4] Saltzman C, Brandser E, Berbaum K, DeGnore L, Holmes J, Katcherian D, et al. Reliability of standard foot radiographic measurements. Foot Ankle Int 1994;15:661–5. [5] Bryant A, Tinley P, Singer K. A comparison of radiographic measurements in normal, hallux valgus, and hallux limitus feet. J Foot Ankle Surg 2000;39(Jan–Feb (1)):39–43. [6] Lee KM, Ahn S, Chung CY, Sung KH, Park MS. Reliability and Relationship of radiographic measurements in hallux valgus. Clin Orthop Relat Res 2012;470(9):2613–21. [7] Saro C, Johnson DN, Martinez De Aragón J, Lindgren U, Felländer-Tsai L. Reliability of radiological and cosmetic measurements in hallux valgus. Acta Radiol 2005;46(Dec (8)):843–51. [8] Mann RA, Coughlin MJ. Hallux valgus—etiology, anatomy, treatment and surgical considerations. Clin Orthop Relat Res 1981;157:31–41. [9] Sanhudo JV, Gomes JE, Rabello MC, Delucca G. Interobserver and intraobserver reproducibility of hallux valgus angular measurements and the study of a linear measurement. Foot Ankle Spec 2012;5(Dec (6)):374–7. [10] Kuwano T, Nagamine R, Sakaki K, Urabe K, Iwamoto Y. New radiographic analysis of sesamoid rotation in hallux valgus: comparison with conventional evaluation methods. Foot Ankle Int 2002;23(9):811–7. [11] Yildrim Y, Abukoglu C, Erol B, Esemenlli T. Effect of metatarsophalangeal position on the reliability of the tangential sesamoid view in determining sesamoid position. Foot Ankle Int 2005;26:247–50.
Please cite this article in press as: Panchani S, et al. Inter and intra-observer reliability in assessment of the position of the lateral sesamoid in determining the severity of hallux valgus. Foot (2015), http://dx.doi.org/10.1016/j.foot.2015.10.001